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ball mills

In all ore dressing and milling Operations, including flotation, cyanidation, gravity concentration, and amalgamation, the Working Principle is to crush and grind, often with rob mill & ball mills, the ore in order to liberate the minerals. In the chemical and process industries, grinding is an important step in preparing raw materials for subsequent treatment.In present day practice, ore is reduced to a size many times finer than can be obtained with crushers. Over a period of many years various fine grinding machines have been developed and used, but the ball mill has become standard due to its simplicity and low operating cost.

A ball millefficiently operated performs a wide variety of services. In small milling plants, where simplicity is most essential, it is not economical to use more than single stage crushing, because the Steel-Head Ball or Rod Mill will take up to 2 feed and grind it to the desired fineness. In larger plants where several stages of coarse and fine crushing are used, it is customary to crush from 1/2 to as fine as 8 mesh.

Many grinding circuits necessitate regrinding of concentrates or middling products to extremely fine sizes to liberate the closely associated minerals from each other. In these cases, the feed to the ball mill may be from 10 to 100 mesh or even finer.

Where the finished product does not have to be uniform, a ball mill may be operated in open circuit, but where the finished product must be uniform it is essential that the grinding mill be used in closed circuit with a screen, if a coarse product is desired, and with a classifier if a fine product is required. In most cases it is desirable to operate the grinding mill in closed circuit with a screen or classifier as higher efficiency and capacity are obtained. Often a mill using steel rods as the grinding medium is recommended, where the product must have the minimum amount of fines (rods give a more nearly uniform product).

Often a problem requires some study to determine the economic fineness to which a product can or should be ground. In this case the 911Equipment Company offers its complete testing service so that accurate grinding mill size may be determined.

Until recently many operators have believed that one particular type of grinding mill had greater efficiency and resulting capacity than some other type. However, it is now commonly agreed and accepted that the work done by any ballmill depends directly upon the power input; the maximum power input into any ball or rod mill depends upon weight of grinding charge, mill speed, and liner design.

The apparent difference in capacities between grinding mills (listed as being the same size) is due to the fact that there is no uniform method of designating the size of a mill, for example: a 5 x 5 Ball Mill has a working diameter of 5 inside the liners and has 20 per cent more capacity than all other ball mills designated as 5 x 5 where the shell is 5 inside diameter and the working diameter is only 48 with the liners in place.

Ball-Rod Mills, based on 4 liners and capacity varying as 2.6 power of mill diameter, on the 5 size give 20 per cent increased capacity; on the 4 size, 25 per cent; and on the 3 size, 28 per cent. This fact should be carefully kept in mind when determining the capacity of a Steel- Head Ball-Rod Mill, as this unit can carry a greater ball or rod charge and has potentially higher capacity in a given size when the full ball or rod charge is carried.

A mill shorter in length may be used if the grinding problem indicates a definite power input. This allows the alternative of greater capacity at a later date or a considerable saving in first cost with a shorter mill, if reserve capacity is not desired. The capacities of Ball-Rod Mills are considerably higher than many other types because the diameters are measured inside the liners.

The correct grinding mill depends so much upon the particular ore being treated and the product desired, that a mill must have maximum flexibility in length, type of grinding medium, type of discharge, and speed.With the Ball-Rod Mill it is possible to build this unit in exact accordance with your requirements, as illustrated.

To best serve your needs, the Trunnion can be furnished with small (standard), medium, or large diameter opening for each type of discharge. The sketch shows diagrammatic arrangements of the four different types of discharge for each size of trunnion opening, and peripheral discharge is described later.

Ball-Rod Mills of the grate discharge type are made by adding the improved type of grates to a standard Ball-Rod Mill. These grates are bolted to the discharge head in much the same manner as the standard headliners.

The grates are of alloy steel and are cast integral with the lifter bars which are essential to the efficient operation of this type of ball or rod mill. These lifter bars have a similar action to a pump:i. e., in lifting the product so as to discharge quickly through the mill trunnion.

These Discharge Grates also incorporate as an integral part, a liner between the lifters and steel head of the ball mill to prevent wear of the mill head. By combining these parts into a single casting, repairs and maintenance are greatly simplified. The center of the grate discharge end of this mill is open to permit adding of balls or for adding water to the mill through the discharge end.

Instead of being constructed of bars cast into a frame, Grates are cast entire and have cored holes which widen toward the outside of the mill similar to the taper in grizzly bars. The grate type discharge is illustrated.

The peripheral discharge type of Ball-Rod Mill is a modification of the grate type, and is recommended where a free gravity discharge is desired. It is particularly applicable when production of too many fine particles is detrimental and a quick pass through the mill is desired, and for dry grinding.

The drawings show the arrangement of the peripheral discharge. The discharge consists of openings in the shell into which bushings with holes of the desired size are inserted. On the outside of the mill, flanges are used to attach a stationary discharge hopper to prevent pulp splash or too much dust.

The mill may be operated either as a peripheral discharge or a combination or peripheral and trunnion discharge unit, depending on the desired operating conditions. If at any time the peripheral discharge is undesirable, plugs inserted into the bushings will convert the mill to a trunnion discharge type mill.

Unless otherwise specified, a hard iron liner is furnished. This liner is made of the best grade white iron and is most serviceable for the smaller size mills where large balls are not used. Hard iron liners have a much lower first cost.

Electric steel, although more expensive than hard iron, has advantage of minimum breakage and allows final wear to thinner section. Steel liners are recommended when the mills are for export or where the source of liner replacement is at a considerable distance.

Molychrome steel has longer wearing qualities and greater strength than hard iron. Breakage is not so apt to occur during shipment, and any size ball can be charged into a mill equipped with molychrome liners.

Manganese liners for Ball-Rod Mills are the world famous AMSCO Brand, and are the best obtainable. The first cost is the highest, but in most cases the cost per ton of ore ground is the lowest. These liners contain 12 to 14% manganese.

The feed and discharge trunnions are provided with cast iron or white iron throat liners. As these parts are not subjected to impact and must only withstand abrasion, alloys are not commonly used but can be supplied.

Gears for Ball-Rod Mills drives are furnished as standard on the discharge end of the mill where they are out of the way of the classifier return, scoop feeder, or original feed. Due to convertible type construction the mills can be furnished with gears on the feed end. Gear drives are available in two alternative combinations, which are:

All pinions are properly bored, key-seated, and pressed onto the steel countershaft, which is oversize and properly keyseated for the pinion and drive pulleys or sheaves. The countershaft operates on high grade, heavy duty, nickel babbitt bearings.

Any type of drive can be furnished for Ball-Rod Mills in accordance with your requirements. Belt drives are available with pulleys either plain or equipped with friction clutch. Various V- Rope combinations can also be supplied.

The most economical drive to use up to 50 H. P., is a high starting torque motor connected to the pinion shaft by means of a flat or V-Rope drive. For larger size motors the wound rotor (slip ring) is recommended due to its low current requirement in starting up the ball mill.

Should you be operating your own power plant or have D. C. current, please specify so that there will be no confusion as to motor characteristics. If switches are to be supplied, exact voltage to be used should be given.

Even though many ores require fine grinding for maximum recovery, most ores liberate a large percentage of the minerals during the first pass through the grinding unit. Thus, if the free minerals can be immediately removed from the ball mill classifier circuit, there is little chance for overgrinding.

This is actually what has happened wherever Mineral Jigs or Unit Flotation Cells have been installed in the ball mill classifier circuit. With the installation of one or both of these machines between the ball mill and classifier, as high as 70 per cent of the free gold and sulphide minerals can be immediately removed, thus reducing grinding costs and improving over-all recovery. The advantage of this method lies in the fact that heavy and usually valuable minerals, which otherwise would be ground finer because of their faster settling in the classifier and consequent return to the grinding mill, are removed from the circuit as soon as freed. This applies particularly to gold and lead ores.

Ball-Rod Mills have heavy rolled steel plate shells which are arc welded inside and outside to the steel heads or to rolled steel flanges, depending upon the type of mill. The double welding not only gives increased structural strength, but eliminates any possibility of leakage.

Where a single or double flanged shell is used, the faces are accurately machined and drilled to template to insure perfect fit and alignment with the holes in the head. These flanges are machined with male and female joints which take the shearing stresses off the bolts.

The Ball-Rod Mill Heads are oversize in section, heavily ribbed and are cast from electric furnace steel which has a strength of approximately four times that of cast iron. The head and trunnion bearings are designed to support a mill with length double its diameter. This extra strength, besides eliminating the possibility of head breakage or other structural failure (either while in transit or while in service), imparts to Ball-Rod Mills a flexibility heretofore lacking in grinding mills. Also, for instance, if you have a 5 x 5 mill, you can add another 5 shell length and thus get double the original capacity; or any length required up to a maximum of 12 total length.

On Type A mills the steel heads are double welded to the rolled steel shell. On type B and other flanged type mills the heads are machined with male and female joints to match the shell flanges, thus taking the shearing stresses from the heavy machine bolts which connect the shell flanges to the heads.

The manhole cover is protected from wear by heavy liners. An extended lip is provided for loosening the door with a crow-bar, and lifting handles are also provided. The manhole door is furnished with suitable gaskets to prevent leakage.

The mill trunnions are carried on heavy babbitt bearings which provide ample surface to insure low bearing pressure. If at any time the normal length is doubled to obtain increased capacity, these large trunnion bearings will easily support the additional load. Trunnion bearings are of the rigid type, as the perfect alignment of the trunnion surface on Ball-Rod Mills eliminates any need for the more expensive self-aligning type of bearing.

The cap on the upper half of the trunnion bearing is provided with a shroud which extends over the drip flange of the trunnion and effectively prevents the entrance of dirt or grit. The bearing has a large space for wool waste and lubricant and this is easily accessible through a large opening which is covered to prevent dirt from getting into the bearing.Ball and socket bearings can be furnished.

Scoop Feeders for Ball-Rod Mills are made in various radius sizes. Standard scoops are made of cast iron and for the 3 size a 13 or 19 feeder is supplied, for the 4 size a 30 or 36, for the 5 a 36 or 42, and for the 6 a 42 or 48 feeder. Welded steel scoop feeders can, however, be supplied in any radius.

The correct size of feeder depends upon the size of the classifier, and the smallest feeder should be used which will permit gravity flow for closed circuit grinding between classifier and the ball or rod mill. All feeders are built with a removable wearing lip which can be easily replaced and are designed to give minimum scoop wear.

A combination drum and scoop feeder can be supplied if necessary. This feeder is made of heavy steel plate and strongly welded. These drum-scoop feeders are available in the same sizes as the cast iron feeders but can be built in any radius. Scoop liners can be furnished.

The trunnions on Ball-Rod Mills are flanged and carefully machined so that scoops are held in place by large machine bolts and not cap screws or stud bolts. The feed trunnion flange is machined with a shoulder for insuring a proper fit for the feed scoop, and the weight of the scoop is carried on this shoulder so that all strain is removed from the bolts which hold the scoop.

High carbon steel rods are recommended, hot rolled, hot sawed or sheared, to a length of 2 less than actual length of mill taken inside the liners. The initial rod charge is generally a mixture ranging from 1.5 to 3 in diameter. During operation, rod make-up is generally the maximum size. The weights per lineal foot of rods of various diameters are approximately: 1.5 to 6 lbs.; 2-10.7 lbs.; 2.5-16.7 lbs.; and 3-24 lbs.

Forged from the best high carbon manganese steel, they are of the finest quality which can be produced and give long, satisfactory service. Data on ball charges for Ball-Rod Mills are listed in Table 5. Further information regarding grinding balls is included in Table 6.

Rod Mills has a very define and narrow discharge product size range. Feeding a Rod Mill finer rocks will greatly impact its tonnage while not significantly affect its discharge product sizes. The 3.5 diameter rod of a mill, can only grind so fine.

Crushers are well understood by most. Rod and Ball Mills not so much however as their size reduction actions are hidden in the tube (mill). As for Rod Mills, the image above best expresses what is going on inside. As rocks is feed into the mill, they are crushed (pinched) by the weight of its 3.5 x 16 rods at one end while the smaller particles migrate towards the discharge end and get slightly abraded (as in a Ball Mill) on the way there.

We haveSmall Ball Mills for sale coming in at very good prices. These ball mills are relatively small, bearing mounted on a steel frame. All ball mills are sold with motor, gears, steel liners and optional grinding media charge/load.

Ball Mills or Rod Mills in a complete range of sizes up to 10 diameter x20 long, offer features of operation and convertibility to meet your exactneeds. They may be used for pulverizing and either wet or dry grindingsystems. Mills are available in both light-duty and heavy-duty constructionto meet your specific requirements.

All Mills feature electric cast steel heads and heavy rolled steelplate shells. Self-aligning main trunnion bearings on large mills are sealedand internally flood-lubricated. Replaceable mill trunnions. Pinion shaftbearings are self-aligning, roller bearing type, enclosed in dust-tightcarrier. Adjustable, single-unit soleplate under trunnion and drive pinionsfor perfect, permanent gear alignment.

Ball Mills can be supplied with either ceramic or rubber linings for wet or dry grinding, for continuous or batch type operation, in sizes from 15 x 21 to 8 x 12. High density ceramic linings of uniform hardness male possible thinner linings and greater and more effective grinding volume. Mills are shipped with liners installed.

Complete laboratory testing service, mill and air classifier engineering and proven equipment make possible a single source for your complete dry-grinding mill installation. Units available with air swept design and centrifugal classifiers or with elevators and mechanical type air classifiers. All sizes and capacities of units. Laboratory-size air classifier also available.

A special purpose batch mill designed especially for grinding and mixing involving acids and corrosive materials. No corners mean easy cleaning and choice of rubber or ceramic linings make it corrosion resistant. Shape of mill and ball segregation gives preferential grinding action for grinding and mixing of pigments and catalysts. Made in 2, 3 and 4 diameter grinding drums.

Nowadays grinding mills are almost extensively used for comminution of materials ranging from 5 mm to 40 mm (3/161 5/8) down to varying product sizes. They have vast applications within different branches of industry such as for example the ore dressing, cement, lime, porcelain and chemical industries and can be designed for continuous as well as batch grinding.

Ball mills can be used for coarse grinding as described for the rod mill. They will, however, in that application produce more fines and tramp oversize and will in any case necessitate installation of effective classification.If finer grinding is wanted two or three stage grinding is advisable as for instant primary rod mill with 75100 mm (34) rods, secondary ball mill with 2540 mm(11) balls and possibly tertiary ball mill with 20 mm () balls or cylpebs.To obtain a close size distribution in the fine range the specific surface of the grinding media should be as high as possible. Thus as small balls as possible should be used in each stage.

The principal field of rod mill usage is the preparation of products in the 5 mm0.4 mm (4 mesh to 35 mesh) range. It may sometimes be recommended also for finer grinding. Within these limits a rod mill is usually superior to and more efficient than a ball mill. The basic principle for rod grinding is reduction by line contact between rods extending the full length of the mill, resulting in selective grinding carried out on the largest particle sizes. This results in a minimum production of extreme fines or slimes and more effective grinding work as compared with a ball mill. One stage rod mill grinding is therefore suitable for preparation of feed to gravimetric ore dressing methods, certain flotation processes with slime problems and magnetic cobbing. Rod mills are frequently used as primary mills to produce suitable feed to the second grinding stage. Rod mills have usually a length/diameter ratio of at least 1.4.

Tube mills are in principle to be considered as ball mills, the basic difference being that the length/diameter ratio is greater (35). They are commonly used for surface cleaning or scrubbing action and fine grinding in open circuit.

In some cases it is suitable to use screened fractions of the material as grinding media. Such mills are usually called pebble mills, but the working principle is the same as for ball mills. As the power input is approximately directly proportional to the volume weight of the grinding media, the power input for pebble mills is correspondingly smaller than for a ball mill.

A dry process requires usually dry grinding. If the feed is wet and sticky, it is often necessary to lower the moisture content below 1 %. Grinding in front of wet processes can be done wet or dry. In dry grinding the energy consumption is higher, but the wear of linings and charge is less than for wet grinding, especially when treating highly abrasive and corrosive material. When comparing the economy of wet and dry grinding, the different costs for the entire process must be considered.

An increase in the mill speed will give a directly proportional increase in mill power but there seems to be a square proportional increase in the wear. Rod mills generally operate within the range of 6075 % of critical speed in order to avoid excessive wear and tangled rods. Ball and pebble mills are usually operated at 7085 % of critical speed. For dry grinding the speed is usually somewhat lower.

The mill lining can be made of rubber or different types of steel (manganese or Ni-hard) with liner types according to the customers requirements. For special applications we can also supply porcelain, basalt and other linings.

The mill power is approximately directly proportional to the charge volume within the normal range. When calculating a mill 40 % charge volume is generally used. In pebble and ball mills quite often charge volumes close to 50 % are used. In a pebble mill the pebble consumption ranges from 315 % and the charge has to be controlled automatically to maintain uniform power consumption.

In all cases the net energy consumption per ton (kWh/ton) must be known either from previous experience or laboratory tests before mill size can be determined. The required mill net power P kW ( = ton/hX kWh/ton) is obtained from

Trunnions of S.G. iron or steel castings with machined flange and bearing seat incl. device for dismantling the bearings. For smaller mills the heads and trunnions are sometimes made in grey cast iron.

The mills can be used either for dry or wet, rod or ball grinding. By using a separate attachment the discharge end can be changed so that the mills can be used for peripheral instead of overflow discharge.

ball mills - an overview | sciencedirect topics

A ball mill is a type of grinder used to grind and blend bulk material into QDs/nanosize using different sized balls. The working principle is simple; impact and attrition size reduction take place as the ball drops from near the top of a rotating hollow cylindrical shell. The nanostructure size can be varied by varying the number and size of balls, the material used for the balls, the material used for the surface of the cylinder, the rotation speed, and the choice of material to be milled. Ball mills are commonly used for crushing and grinding the materials into an extremely fine form. The ball mill contains a hollow cylindrical shell that rotates about its axis. This cylinder is filled with balls that are made of stainless steel or rubber to the material contained in it. Ball mills are classified as attritor, horizontal, planetary, high energy, or shaker.

Grinding elements in ball mills travel at different velocities. Therefore, collision force, direction and kinetic energy between two or more elements vary greatly within the ball charge. Frictional wear or rubbing forces act on the particles, as well as collision energy. These forces are derived from the rotational motion of the balls and movement of particles within the mill and contact zones of colliding balls.

By rotation of the mill body, due to friction between mill wall and balls, the latter rise in the direction of rotation till a helix angle does not exceed the angle of repose, whereupon, the balls roll down. Increasing of rotation rate leads to growth of the centrifugal force and the helix angle increases, correspondingly, till the component of weight strength of balls become larger than the centrifugal force. From this moment the balls are beginning to fall down, describing during falling certain parabolic curves (Figure 2.7). With the further increase of rotation rate, the centrifugal force may become so large that balls will turn together with the mill body without falling down. The critical speed n (rpm) when the balls are attached to the wall due to centrifugation:

where Dm is the mill diameter in meters. The optimum rotational speed is usually set at 6580% of the critical speed. These data are approximate and may not be valid for metal particles that tend to agglomerate by welding.

The degree of filling the mill with balls also influences productivity of the mill and milling efficiency. With excessive filling, the rising balls collide with falling ones. Generally, filling the mill by balls must not exceed 3035% of its volume.

The mill productivity also depends on many other factors: physical-chemical properties of feed material, filling of the mill by balls and their sizes, armor surface shape, speed of rotation, milling fineness and timely moving off of ground product.

where b.ap is the apparent density of the balls; l is the degree of filling of the mill by balls; n is revolutions per minute; 1, and 2 are coefficients of efficiency of electric engine and drive, respectively.

A feature of ball mills is their high specific energy consumption; a mill filled with balls, working idle, consumes approximately as much energy as at full-scale capacity, i.e. during grinding of material. Therefore, it is most disadvantageous to use a ball mill at less than full capacity.

Grinding elements in ball mills travel at different velocities. Therefore, collision force, direction, and kinetic energy between two or more elements vary greatly within the ball charge. Frictional wear or rubbing forces act on the particles as well as collision energy. These forces are derived from the rotational motion of the balls and the movement of particles within the mill and contact zones of colliding balls.

By the rotation of the mill body, due to friction between the mill wall and balls, the latter rise in the direction of rotation until a helix angle does not exceed the angle of repose, whereupon the balls roll down. Increasing the rotation rate leads to the growth of the centrifugal force and the helix angle increases, correspondingly, until the component of the weight strength of balls becomes larger than the centrifugal force. From this moment, the balls are beginning to fall down, describing certain parabolic curves during the fall (Fig. 2.10).

With the further increase of rotation rate, the centrifugal force may become so large that balls will turn together with the mill body without falling down. The critical speed n (rpm) when the balls remain attached to the wall with the aid of centrifugal force is:

where Dm is the mill diameter in meters. The optimum rotational speed is usually set at 65%80% of the critical speed. These data are approximate and may not be valid for metal particles that tend to agglomerate by welding.

where db.max is the maximum size of the feed (mm), is the compression strength (MPa), E is the modulus of elasticity (MPa), b is the density of material of balls (kg/m3), and D is the inner diameter of the mill body (m).

The degree of filling the mill with balls also influences the productivity of the mill and milling efficiency. With excessive filling, the rising balls collide with falling ones. Generally, filling the mill by balls must not exceed 30%35% of its volume.

The productivity of ball mills depends on the drum diameter and the relation of drum diameter and length. The optimum ratio between length L and diameter D, L:D, is usually accepted in the range 1.561.64. The mill productivity also depends on many other factors, including the physical-chemical properties of the feed material, the filling of the mill by balls and their sizes, the armor surface shape, the speed of rotation, the milling fineness, and the timely moving off of the ground product.

where D is the drum diameter, L is the drum length, b.ap is the apparent density of the balls, is the degree of filling of the mill by balls, n is the revolutions per minute, and 1, and 2 are coefficients of efficiency of electric engine and drive, respectively.

A feature of ball mills is their high specific energy consumption. A mill filled with balls, working idle, consumes approximately as much energy as at full-scale capacity, that is, during the grinding of material. Therefore, it is most disadvantageous to use a ball mill at less than full capacity.

Milling time in tumbler mills is longer to accomplish the same level of blending achieved in the attrition or vibratory mill, but the overall productivity is substantially greater. Tumbler mills usually are used to pulverize or flake metals, using a grinding aid or lubricant to prevent cold welding agglomeration and to minimize oxidation [23].

Cylindrical Ball Mills differ usually in steel drum design (Fig. 2.11), which is lined inside by armor slabs that have dissimilar sizes and form a rough inside surface. Due to such juts, the impact force of falling balls is strengthened. The initial material is fed into the mill by a screw feeder located in a hollow trunnion; the ground product is discharged through the opposite hollow trunnion.

Cylindrical screen ball mills have a drum with spiral curved plates with longitudinal slits between them. The ground product passes into these slits and then through a cylindrical sieve and is discharged via the unloading funnel of the mill body.

Conical Ball Mills differ in mill body construction, which is composed of two cones and a short cylindrical part located between them (Fig. 2.12). Such a ball mill body is expedient because efficiency is appreciably increased. Peripheral velocity along the conical drum scales down in the direction from the cylindrical part to the discharge outlet; the helix angle of balls is decreased and, consequently, so is their kinetic energy. The size of the disintegrated particles also decreases as the discharge outlet is approached and the energy used decreases. In a conical mill, most big balls take up a position in the deeper, cylindrical part of the body; thus, the size of the balls scales down in the direction of the discharge outlet.

For emptying, the conical mill is installed with a slope from bearing to one. In wet grinding, emptying is realized by the decantation principle, that is, by means of unloading through one of two trunnions.

With dry grinding, these mills often work in a closed cycle. A scheme of the conical ball mill supplied with an air separator is shown in Fig. 2.13. Air is fed to the mill by means of a fan. Carried off by air currents, the product arrives at the air separator, from which the coarse particles are returned by gravity via a tube into the mill. The finished product is trapped in a cyclone while the air is returned in the fan.

The ball mill is a tumbling mill that uses steel balls as the grinding media. The length of the cylindrical shell is usually 11.5 times the shell diameter (Figure 8.11). The feed can be dry, with less than 3% moisture to minimize ball coating, or slurry containing 2040% water by weight. Ball mills are employed in either primary or secondary grinding applications. In primary applications, they receive their feed from crushers, and in secondary applications, they receive their feed from rod mills, AG mills, or SAG mills.

Ball mills are filled up to 40% with steel balls (with 3080mm diameter), which effectively grind the ore. The material that is to be ground fills the voids between the balls. The tumbling balls capture the particles in ball/ball or ball/liner events and load them to the point of fracture.

When hard pebbles rather than steel balls are used for the grinding media, the mills are known as pebble mills. As mentioned earlier, pebble mills are widely used in the North American taconite iron ore operations. Since the weight of pebbles per unit volume is 3555% of that of steel balls, and as the power input is directly proportional to the volume weight of the grinding medium, the power input and capacity of pebble mills are correspondingly lower. Thus, in a given grinding circuit, for a certain feed rate, a pebble mill would be much larger than a ball mill, with correspondingly a higher capital cost. However, the increase in capital cost is justified economically by a reduction in operating cost attributed to the elimination of steel grinding media.

In general, ball mills can be operated either wet or dry and are capable of producing products in the order of 100m. This represents reduction ratios of as great as 100. Very large tonnages can be ground with these ball mills because they are very effective material handling devices. Ball mills are rated by power rather than capacity. Today, the largest ball mill in operation is 8.53m diameter and 13.41m long with a corresponding motor power of 22MW (Toromocho, private communications).

Modern ball mills consist of two chambers separated by a diaphragm. In the first chamber the steel-alloy balls (also described as charge balls or media) are about 90mm diameter. The mill liners are designed to lift the media as the mill rotates, so the comminution process in the first chamber is dominated by crushing. In the second chamber the ball diameters are of smaller diameter, between 60 and 15mm. In this chamber the lining is typically a classifying lining which sorts the media so that ball size reduces towards the discharge end of the mill. Here, comminution takes place in the rolling point-contact zone between each charge ball. An example of a two chamber ball mill is illustrated in Fig. 2.22.15

Much of the energy consumed by a ball mill generates heat. Water is injected into the second chamber of the mill to provide evaporative cooling. Air flow through the mill is one medium for cement transport but also removes water vapour and makes some contribution to cooling.

Grinding is an energy intensive process and grinding more finely than necessary wastes energy. Cement consists of clinker, gypsum and other components mostly more easily ground than clinker. To minimise over-grinding modern ball mills are fitted with dynamic separators (otherwise described as classifiers or more simply as separators). The working principle is that cement is removed from the mill before over-grinding has taken place. The cement is then separated into a fine fraction, which meets finished product requirements, and a coarse fraction which is returned to mill inlet. Recirculation factor, that is, the ratio of mill throughput to fresh feed is up to three. Beyond this, efficiency gains are minimal.

For more than 50years vertical mills have been the mill of choice for grinding raw materials into raw meal. More recently they have become widely used for cement production. They have lower specific energy consumption than ball mills and the separator, as in raw mills, is integral with the mill body.

In the Loesche mill, Fig. 2.23,16 two pairs of rollers are used. In each pair the first, smaller diameter, roller stabilises the bed prior to grinding which takes place under the larger roller. Manufacturers use different technologies for bed stabilisation.

Comminution in ball mills and vertical mills differs fundamentally. In a ball mill, size reduction takes place by impact and attrition. In a vertical mill the bed of material is subject to such a high pressure that individual particles within the bed are fractured, even though the particles are very much smaller than the bed thickness.

Early issues with vertical mills, such as narrower PSD and modified cement hydration characteristics compared with ball mills, have been resolved. One modification has been to install a hot gas generator so the gas temperature is high enough to partially dehydrate the gypsum.

For many decades the two-compartment ball mill in closed circuit with a high-efficiency separator has been the mill of choice. In the last decade vertical mills have taken an increasing share of the cement milling market, not least because the specific power consumption of vertical mills is about 30% less than that of ball mills and for finely ground cement less still. The vertical mill has a proven track record in grinding blastfurnace slag, where it has the additional advantage of being a much more effective drier of wet feedstock than a ball mill.

The vertical mill is more complex but its installation is more compact. The relative installed capital costs tend to be site specific. Historically the installed cost has tended to be slightly higher for the vertical mill.

Special graph paper is used with lglg(1/R(x)) on the abscissa and lg(x) on the ordinate axes. The higher the value of n, the narrower the particle size distribution. The position parameter is the particle size with the highest mass density distribution, the peak of the mass density distribution curve.

Vertical mills tend to produce cement with a higher value of n. Values of n normally lie between 0.8 and 1.2, dependent particularly on cement fineness. The position parameter is, of course, lower for more finely ground cements.

Separator efficiency is defined as specific power consumption reduction of the mill open-to-closed-circuit with the actual separator, compared with specific power consumption reduction of the mill open-to-closed-circuit with an ideal separator.

As shown in Fig. 2.24, circulating factor is defined as mill mass flow, that is, fresh feed plus separator returns. The maximum power reduction arising from use of an ideal separator increases non-linearly with circulation factor and is dependent on Rf, normally based on residues in the interval 3245m. The value of the comminution index, W, is also a function of Rf. The finer the cement, the lower Rf and the greater the maximum power reduction. At C = 2 most of maximum power reduction is achieved, but beyond C = 3 there is very little further reduction.

Separator particle separation performance is assessed using the Tromp curve, a graph of percentage separator feed to rejects against particle size range. An example is shown in Fig. 2.25. Data required is the PSD of separator feed material and of rejects and finished product streams. The bypass and slope provide a measure of separator performance.

The particle size is plotted on a logarithmic scale on the ordinate axis. The percentage is plotted on the abscissa either on a linear (as shown here) or on a Gaussian scale. The advantage of using the Gaussian scale is that the two parts of the graph can be approximated by two straight lines.

The measurement of PSD of a sample of cement is carried out using laser-based methodologies. It requires a skilled operator to achieve consistent results. Agglomeration will vary dependent on whether grinding aid is used. Different laser analysis methods may not give the same results, so for comparative purposes the same method must be used.

The ball mill is a cylindrical drum (or cylindrical conical) turning around its horizontal axis. It is partially filled with grinding bodies: cast iron or steel balls, or even flint (silica) or porcelain bearings. Spaces between balls or bearings are occupied by the load to be milled.

Following drum rotation, balls or bearings rise by rolling along the cylindrical wall and descending again in a cascade or cataract from a certain height. The output is then milled between two grinding bodies.

Ball mills could operate dry or even process a water suspension (almost always for ores). Dry, it is fed through a chute or a screw through the units opening. In a wet path, a system of scoops that turn with the mill is used and it plunges into a stationary tank.

Mechanochemical synthesis involves high-energy milling techniques and is generally carried out under controlled atmospheres. Nanocomposite powders of oxide, nonoxide, and mixed oxide/nonoxide materials can be prepared using this method. The major drawbacks of this synthesis method are: (1) discrete nanoparticles in the finest size range cannot be prepared; and (2) contamination of the product by the milling media.

More or less any ceramic composite powder can be synthesized by mechanical mixing of the constituent phases. The main factors that determine the properties of the resultant nanocomposite products are the type of raw materials, purity, the particle size, size distribution, and degree of agglomeration. Maintaining purity of the powders is essential for avoiding the formation of a secondary phase during sintering. Wet ball or attrition milling techniques can be used for the synthesis of homogeneous powder mixture. Al2O3/SiC composites are widely prepared by this conventional powder mixing route by using ball milling [70]. However, the disadvantage in the milling step is that it may induce certain pollution derived from the milling media.

In this mechanical method of production of nanomaterials, which works on the principle of impact, the size reduction is achieved through the impact caused when the balls drop from the top of the chamber containing the source material.

A ball mill consists of a hollow cylindrical chamber (Fig. 6.2) which rotates about a horizontal axis, and the chamber is partially filled with small balls made of steel, tungsten carbide, zirconia, agate, alumina, or silicon nitride having diameter generally 10mm. The inner surface area of the chamber is lined with an abrasion-resistant material like manganese, steel, or rubber. The magnet, placed outside the chamber, provides the pulling force to the grinding material, and by changing the magnetic force, the milling energy can be varied as desired. The ball milling process is carried out for approximately 100150h to obtain uniform-sized fine powder. In high-energy ball milling, vacuum or a specific gaseous atmosphere is maintained inside the chamber. High-energy mills are classified into attrition ball mills, planetary ball mills, vibrating ball mills, and low-energy tumbling mills. In high-energy ball milling, formation of ceramic nano-reinforcement by in situ reaction is possible.

It is an inexpensive and easy process which enables industrial scale productivity. As grinding is done in a closed chamber, dust, or contamination from the surroundings is avoided. This technique can be used to prepare dry as well as wet nanopowders. Composition of the grinding material can be varied as desired. Even though this method has several advantages, there are some disadvantages. The major disadvantage is that the shape of the produced nanoparticles is not regular. Moreover, energy consumption is relatively high, which reduces the production efficiency. This technique is suitable for the fabrication of several nanocomposites, which include Co- and Cu-based nanomaterials, Ni-NiO nanocomposites, and nanocomposites of Ti,C [71].

Planetary ball mill was used to synthesize iron nanoparticles. The synthesized nanoparticles were subjected to the characterization studies by X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques using a SIEMENS-D5000 diffractometer and Hitachi S-4800. For the synthesis of iron nanoparticles, commercial iron powder having particles size of 10m was used. The iron powder was subjected to planetary ball milling for various period of time. The optimum time period for the synthesis of nanoparticles was observed to be 10h because after that time period, chances of contamination inclined and the particles size became almost constant so the powder was ball milled for 10h to synthesize nanoparticles [11]. Fig. 12 shows the SEM image of the iron nanoparticles.

The vibratory ball mill is another kind of high-energy ball mill that is used mainly for preparing amorphous alloys. The vials capacities in the vibratory mills are smaller (about 10 ml in volume) compared to the previous types of mills. In this mill, the charge of the powder and milling tools are agitated in three perpendicular directions (Fig. 1.6) at very high speed, as high as 1200 rpm.

Another type of the vibratory ball mill, which is used at the van der Waals-Zeeman Laboratory, consists of a stainless steel vial with a hardened steel bottom, and a single hardened steel ball of 6 cm in diameter (Fig. 1.7).

The mill is evacuated during milling to a pressure of 106 Torr, in order to avoid reactions with a gas atmosphere.[44] Subsequently, this mill is suitable for mechanical alloying of some special systems that are highly reactive with the surrounding atmosphere, such as rare earth elements.

In spite of the traditional approaches used for gas-solid reaction at relatively high temperature, Calka etal.[58] and El-Eskandarany etal.[59] proposed a solid-state approach, the so-called reactive ball milling (RBM), used for preparations different families of meal nitrides and hydrides at ambient temperature. This mechanically induced gas-solid reaction can be successfully achieved, using either high- or low-energy ball-milling methods, as shown in Fig.9.5. However, high-energy ball mill is an efficient process for synthesizing nanocrystalline MgH2 powders using RBM technique, it may be difficult to scale up for matching the mass production required by industrial sector. Therefore, from a practical point of view, high-capacity low-energy milling, which can be easily scaled-up to produce large amount of MgH2 fine powders, may be more suitable for industrial mass production.

In both approaches but with different scale of time and milling efficiency, the starting Mg metal powders milled under hydrogen gas atmosphere are practicing to dramatic lattice imperfections such as twinning and dislocations. These defects are caused by plastics deformation coupled with shear and impact forces generated by the ball-milling media.[60] The powders are, therefore, disintegrated into smaller particles with large surface area, where very clean or fresh oxygen-free active surfaces of the powders are created. Moreover, these defects, which are intensively located at the grain boundaries, lead to separate micro-scaled Mg grains into finer grains capable to getter hydrogen by the first atomically clean surfaces to form MgH2 nanopowders.

Fig.9.5 illustrates common lab scale procedure for preparing MgH2 powders, starting from pure Mg powders, using RBM via (1) high-energy and (2) low-energy ball milling. The starting material can be Mg-rods, in which they are processed via sever plastic deformation,[61] using for example cold-rolling approach,[62] as illustrated in Fig.9.5. The heavily deformed Mg-rods obtained after certain cold rolling passes can be snipped into small chips and then ball-milled under hydrogen gas to produce MgH2 powders.[8]

Planetary ball mills are the most popular mills used in scientific research for synthesizing MgH2 nanopowders. In this type of mill, the ball-milling media have considerably high energy, because milling stock and balls come off the inner wall of the vial and the effective centrifugal force reaches up to 20 times gravitational acceleration. The centrifugal forces caused by the rotation of the supporting disc and autonomous turning of the vial act on the milling charge (balls and powders). Since the turning directions of the supporting disc and the vial are opposite, the centrifugal forces alternately are synchronized and opposite. Therefore, the milling media and the charged powders alternatively roll on the inner wall of the vial, and are lifted and thrown off across the bowl at high speed.

In the typical experimental procedure, a certain amount of the Mg (usually in the range between 3 and 10g based on the vials volume) is balanced inside an inert gas atmosphere (argon or helium) in a glove box and sealed together with certain number of balls (e.g., 2050 hardened steel balls) into a hardened steel vial (Fig.9.5A and B), using, for example, a gas-temperature-monitoring system (GST). With the GST system, it becomes possible to monitor the progress of the gas-solid reaction taking place during the RBM process, as shown in Fig.9.5C and D. The temperature and pressure changes in the system during milling can be also used to realize the completion of the reaction and the expected end product during the different stages of milling (Fig.9.5D). The ball-to-powder weight ratio is usually selected to be in the range between 10:1 and 50:1. The vial is then evacuated to the level of 103bar before introducing H2 gas to fill the vial with a pressure of 550bar (Fig.9.5B). The milling process is started by mounting the vial on a high-energy ball mill operated at ambient temperature (Fig.9.5C).

Tumbling mill is cylindrical shell (Fig.9.6AC) that rotates about a horizontal axis (Fig.9.6D). Hydrogen gas is pressurized into the vial (Fig.9.6C) together with Mg powders and ball-milling media, using ball-to-powder weight ratio in the range between 30:1 and 100:1. Mg powder particles meet the abrasive and impacting force (Fig.9.6E), which reduce the particle size and create fresh-powder surfaces (Fig.9.6F) ready to react with hydrogen milling atmosphere.

Figure 9.6. Photographs taken from KISR-EBRC/NAM Lab, Kuwait, show (A) the vial and milling media (balls) and (B) the setup performed to charge the vial with 50bar of hydrogen gas. The photograph in (C) presents the complete setup of GST (supplied by Evico-magnetic, Germany) system prior to start the RBM experiment for preparing of MgH2 powders, using Planetary Ball Mill P400 (provided by Retsch, Germany). GST system allows us to monitor the progress of RBM process, as indexed by temperature and pressure versus milling time (D).

The useful kinetic energy in tumbling mill can be applied to the Mg powder particles (Fig.9.7E) by the following means: (1) collision between the balls and the powders; (2) pressure loading of powders pinned between milling media or between the milling media and the liner; (3) impact of the falling milling media; (4) shear and abrasion caused by dragging of particles between moving milling media; and (5) shock-wave transmitted through crop load by falling milling media. One advantage of this type of mill is that large amount of the powders (100500g or more based on the mill capacity) can be fabricated for each milling run. Thus, it is suitable for pilot and/or industrial scale of MgH2 production. In addition, low-energy ball mill produces homogeneous and uniform powders when compared with the high-energy ball mill. Furthermore, such tumbling mills are cheaper than high-energy mills and operated simply with low-maintenance requirements. However, this kind of low-energy mill requires long-term milling time (more than 300h) to complete the gas-solid reaction and to obtain nanocrystalline MgH2 powders.

Figure 9.7. Photos taken from KISR-EBRC/NAM Lab, Kuwait, display setup of a lab-scale roller mill (1000m in volume) showing (A) the milling tools including the balls (milling media and vial), (B) charging Mg powders in the vial inside inert gas atmosphere glove box, (C) evacuation setup and pressurizing hydrogen gas in the vial, and (D) ball milling processed, using a roller mill. Schematic presentations show the ball positions and movement inside the vial of a tumbler mall mill at a dynamic mode is shown in (E), where a typical ball-powder-ball collusion for a low energy tumbling ball mill is presented in (F).

industrial rigging & machinery movers

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Trivett Contracting has extensive experience providing safe, quality rigging jobs in all types of industries. Our team will work with you to study, plan and execute with the highest level of safety and coordination your next specialized project with complete professionalism to meet your expectations.

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Trivett Contracting is a highly motivated millwright company with a very strong emphasis on maintaining safe work environments and providing high quality work performance.Kevin Gay, KN Platech America Corporation

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We have found Trivett Contracting to be highly motivated on our installations and flexible on their schedules in order to accommodate our corporate deadlines. Additionally, we have seen Trivett demonstrate a good teamwork environment, strong professional leadership and great work ethic while providing superior, fully trained manpower.Kevin Gay, KN Platech America Corporation

I have worked with Trivett Contracting for over 15 years. During this time they have been involved in over $10 million worth of installations surrounding work we have performed together. They are easy to work with, conscientious, safe, and typically reasonably priced. Their people are willing to explain or suggest the best way to make things happen and go out of their way to keep you informed.Mark Llewellyn, Grede LLC New Castle

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ball mill repairs

Trivett Contracting has been servicing Ball mills since its inception from day one. Power generation is an industry we know well, we take pride in keeping your Mills rolling without issues. We have assembled the best quality team in the industry to inspect, maintain and repair Ball mills. Utilizing exceptional labor and the best equipment on the market we can provide the top service and quality for your Mill.

I would fully recommend Trivett Contractings services to anyone. We see their business as a staple and example of a well run company in the Indianapolis area. They are fully capable of handling any job in and out of state. Gregory T. Taylor, Maplehurst Bakeries LLC

Trivett Contracting is a highly motivated millwright company with a very strong emphasis on maintaining safe work environments and providing high quality work performance.Kevin Gay, KN Platech America Corporation

The return on investment has always been immediate when Trivett Contracting is utilized to perform not only repairs and maintenance; but also, project work, and shutdown activities.Mark E. Brady, Pure Power Technologies

We have found Trivett Contracting to be highly motivated on our installations and flexible on their schedules in order to accommodate our corporate deadlines. Additionally, we have seen Trivett demonstrate a good teamwork environment, strong professional leadership and great work ethic while providing superior, fully trained manpower.Kevin Gay, KN Platech America Corporation

I have worked with Trivett Contracting for over 15 years. During this time they have been involved in over $10 million worth of installations surrounding work we have performed together. They are easy to work with, conscientious, safe, and typically reasonably priced. Their people are willing to explain or suggest the best way to make things happen and go out of their way to keep you informed.Mark Llewellyn, Grede LLC New Castle

I predominately have used Trivett for rigging, machine maintenance and fabrication. They have been a Go To company for me when others wouldnt or couldnt provide what I needed.Gregory T. Taylor - Maplehurst Bakeries LLC

Trivett Contracting is considerate and always puts the customer first. The value adds not only show in their cost competitive quoting; but also, when they complete the deliverables on-time and under budget.Mark E. Brady - Pure Power Technologies

"I have called them on numerous occasions with emergency problems and have always gotten a straight answer. Trivett is one of the contractors I consider to be in my go-to group."Mark Llewellyn, Grede LLC New Castle

the most valuable things you need to know about gypsum | fote machinery

The general term gypsum refers to two minerals, raw gypsum and anhydrite. Raw gypsum is calcium dihydrate (Ca [SO4] 2H2O), also known as dihydrate gypsum or plaster. Anhydrite is anhydrous calcium sulfate.

It is a very important industrial raw material that is widely used in construction, building materials, industrial and artistic models, chemical industry (sulfuric acid production, paper filler, paint filler), agriculture, food processing, pharmaceutical, and many other industries and applications.

The plaster of Paris (also known as hemihydrate gypsum), divided into -type gypsum powder and -type gypsum powder, is formed from gypsum raw materials by heating at a high temperature of 105-200 .

The -type gypsum powder has good crystallinity and solidity, so it can be used in ceramic molds, sculptures, gypsum lines and high-end buildings. The -type gypsum powder is mainly used for mortar levelling, gypsum board production, painting, etc.

Gypsum powder can be used as Portland cement retarder in the concrete industry. In agriculture, because gypsum powder is alkaline, it is possible to sprinkle it into the acidic soil to integrate the ph value of the soil so as to make use of a lot of lands.

In the pharmaceutical industry, gypsum is the main medicine in the famous Chinese medicine " Baihu Tang ", which has a good effect in treating acute high fever and thirsty irritable. In addition, dentists use plaster to make models of gums, and surgeons also use plaster to repair the fractures.

Is gypsum harmful to humans? Is gypsum powder safe to eat? Will gypsum kill plants? Here is a video about how gypsum is used, including its uses in toiletries, food additive, fertilizer, chalks, etc. It also shows the process of gypsum.

In recent years, the gypsum industry has developed rapidly. Gypsum building materials are increasingly welcomed by the market and recognized by society with their applications becoming more and more widespread.

According to the US mining forecast, the world's gypsum demand will increase at a rate of 2.5% in the next few years. It is estimated that the world's gypsum demand will reach 300 million tons in 2030. The total annual consumption of the gypsum board will reach 2.04 billion square meters.

With the increase in the market demand for gypsum powder, the requirements for its production technology are getting higher and higher, so the price has risen accordingly. The price of gypsum powder is generally calculated in tons.

Its price varies with its accuracy and use. The price of gypsum powder is between $ 28.8-$ 403.6 per ton according to its whiteness and fineness. The cooked gypsum powder is about $ 28.8-$ 158.6 per ton, the cooking gypsum is about $ 72.1-$ 317.2 per ton, and the refined gypsum powder is about $ 201.8-$ 720.8 per ton.

1. The ex-factory price of Australian recycled gypsum is $ 35.00 per ton, plus $ 25 per ton freight, which is $ 60.00 per ton at the farm gate, and $ 10.00 per ton to spread. Its purity is measured at 17% S wet weight. Total cost of gypsum supply and application per ton of pure CaSO4.2H20 = (35+25+10) 18.6 17 = $ 76.59 per ton.

2. The ex-factory price of gypsum mined in New South Wales is $ 15 per ton, plus $ 40.00 per ton freight, which is $ 60.00 per ton at the farm gate, and $ 11.00 per ton to spread. Its purity is measured at 15% S wet weight. Total cost of gypsum supply and application per ton of pure CaSO4.2H20 = (15+40+11) 18.6 15 = $ 81.84 per ton.

The world's major gypsum producing countries are the United States, Iran, China, Brazil, Canada, Mexico, Spain, Thailand, etc. The United States, Brazil, China, and Canada are rich in gypsum resources.

The largest consumption area of gypsum is the building decoration material industry, which is mainly used to manufacture gypsum boards for construction and decoration. In many countries, the manufacture of slabs accounts for more than 80% of gypsum consumption.

The mining technology of gypsum ore is divided into two categories: the mining of fibrous gypsum ore and the mining of alabaster, ordinary gypsum and anhydrite mines. Due to the difference in physical and mechanical properties of the ore and surrounding rock, the mining technology of these two kinds of gypsum mines is very different.

Fibrous gypsum has low hardness and its rock consolidating coefficient is 1.2 for parallel fibrous gypsum and 1.5 for vertical fibrous gypsum. Because it is brittle, it will easily become fine ore to be lost. Due to the high price of the ore, most fibrous gypsum mines adopt the longwall method, selective mining and filling method.

The mining techniques of alabaster mine, ordinary gypsum mine and anhydrite mine are similar. The room and pillar mining method (generally 8-12 m in width) and breasting method are adopted. The drilling of gypsum ore is easy, but the explosive consumption is large, generally 0.34 kg/t.

The roller drilling rig is modern new drilling equipment. It is suitable for drilling operations of various hardness of minerals and rocks with the characteristics of high perforation efficiency, low operating cost, high mechanization and automation. At present, it has become a widely used perforation equipment in open-pit mines all over the world.

The excavator is composed of the power plant, working device, swing mechanism, control mechanism, transmission system, moving mechanism, auxiliary equipment, etc. The excavator can also perform pouring, lifting, installation, piling, ramming, and pile pulling operations after changing its working device.

After sieving with the vibrating screen equipment, the finished material conforming to the size is sent to the finished product area, while the large material is returned to the crusher for being crushed again until it meets the required size.

The common gypsum crushing equipment is the jaw crusher with a crushing ratio of 4-6. The jaw crusher, which is often used as the primary gypsum crushing equipment, can crush large pieces of gypsum into 150 mm particle size.

If the gypsum crushed by the jaw crusher cannot meet the particle size requirements, secondary gypsum crushing equipment such as cone crushers, hammer crushers, and impact crushers can be equipped to carry out further medium and fine crushing of gypsum. Specific equipment should be configured depends on the actual needs of the customer.

The crushed gypsum is sent to a ball mill for grinding until 90% of it is less than 149 m (100 mesh). The ground gypsum powder leaves the mill in the form of airflow and is collected in the cyclone separator.

The ball mill is mainly a machine for dry or wet grinding of the crushed gypsum. The machine is mainly used for repeated grinding of the raw materials in the barrel through the steel ball medium in the ball mill to complete the ball grinding operation.

The cyclone separator is suitable for purifying non-viscous, non-fibrous dry dust larger than 1-3 microns. It is purification equipment with simple structure, convenient operation, high-temperature resistance and low equipment cost.

Under the design pressure and air volume conditions, solid particles 10 m can be removed. At the operating point, the separation efficiency is 99%, and within 15% of the operating point, the separation efficiency is 97%. Under normal working conditions, the pressure drop of a single cyclone separator at the operating point is not greater than 0.05 MPa.

The gypsum material is lifted by an elevator and transported into the top silo of the rotary kiln preheater. Then, the gypsum material is evenly distributed into rooms of the preheater through the feeding pipe.

In the preheater, gypsum is heated to about 900 C by the flue gas of the roasting kiln at 1150 C, and about 30% of it is decomposed. Then, it is pushed into the rotary kiln by a hydraulic push rod, and -type hemihydrate gypsum (180240 ), anhydrous gypsum (350 ) and overfired gypsum (450700 ) can be produced.

The gypsum produced after calcining and decomposing in the rotary kiln is sent to the cooler to be cooled to below 100 C by the cold air blown in the cooler and discharged. The gypsum from the cooler is sent to the product warehouse via a vibrating feeder, bucket elevator, and belt conveyor.

Gypsum rotary kiln is a kind of thermal equipment for calcining gypsum. Its appearance and shape are similar to lime rotary kiln and cement rotary kiln. Its main structure includes kiln head, kiln tail sealing device, rotary cylinder, supporting device, back-up roll device, etc.

The finished gypsum clinker calcined in the gypsum rotary kiln produced by Fote has the characteristics of high taste, high purity, easy to control during the production process, high mixing degree of raw materials, uniform raw meal composition, high strength grade of the clinker, with less dust in the grinding process, less fly ash in the calcining process and reasonable price.

The large demand and wide application of gypsum powder have stimulated the prosperity of many industries and fields, so the production of high-quality gypsum powder is the general trend of the gypsum powder industry in the future.

Fote Heavy Machinery, as one of the three major mining machinery manufacturers in China, has 38 years of experience. We are always ready to provide you with high-quality milling equipment and the best service.

As a leading mining machinery manufacturer and exporter in China, we are always here to provide you with high quality products and better services. Welcome to contact us through one of the following ways or visit our company and factories.

Based on the high quality and complete after-sales service, our products have been exported to more than 120 countries and regions. Fote Machinery has been the choice of more than 200,000 customers.

ball mill - an overview | sciencedirect topics

The ball mill accepts the SAG or AG mill product. Ball mills give a controlled final grind and produce flotation feed of a uniform size. Ball mills tumble iron or steel balls with the ore. The balls are initially 510 cm diameter but gradually wear away as grinding of the ore proceeds. The feed to ball mills (dry basis) is typically 75 vol.-% ore and 25% steel.

The ball mill is operated in closed circuit with a particle-size measurement device and size-control cyclones. The cyclones send correct-size material on to flotation and direct oversize material back to the ball mill for further grinding.

Grinding elements in ball mills travel at different velocities. Therefore, collision force, direction and kinetic energy between two or more elements vary greatly within the ball charge. Frictional wear or rubbing forces act on the particles, as well as collision energy. These forces are derived from the rotational motion of the balls and movement of particles within the mill and contact zones of colliding balls.

By rotation of the mill body, due to friction between mill wall and balls, the latter rise in the direction of rotation till a helix angle does not exceed the angle of repose, whereupon, the balls roll down. Increasing of rotation rate leads to growth of the centrifugal force and the helix angle increases, correspondingly, till the component of weight strength of balls become larger than the centrifugal force. From this moment the balls are beginning to fall down, describing during falling certain parabolic curves (Figure 2.7). With the further increase of rotation rate, the centrifugal force may become so large that balls will turn together with the mill body without falling down. The critical speed n (rpm) when the balls are attached to the wall due to centrifugation:

where Dm is the mill diameter in meters. The optimum rotational speed is usually set at 6580% of the critical speed. These data are approximate and may not be valid for metal particles that tend to agglomerate by welding.

The degree of filling the mill with balls also influences productivity of the mill and milling efficiency. With excessive filling, the rising balls collide with falling ones. Generally, filling the mill by balls must not exceed 3035% of its volume.

The mill productivity also depends on many other factors: physical-chemical properties of feed material, filling of the mill by balls and their sizes, armor surface shape, speed of rotation, milling fineness and timely moving off of ground product.

where b.ap is the apparent density of the balls; l is the degree of filling of the mill by balls; n is revolutions per minute; 1, and 2 are coefficients of efficiency of electric engine and drive, respectively.

A feature of ball mills is their high specific energy consumption; a mill filled with balls, working idle, consumes approximately as much energy as at full-scale capacity, i.e. during grinding of material. Therefore, it is most disadvantageous to use a ball mill at less than full capacity.

The ball mill is a tumbling mill that uses steel balls as the grinding media. The length of the cylindrical shell is usually 11.5 times the shell diameter (Figure 8.11). The feed can be dry, with less than 3% moisture to minimize ball coating, or slurry containing 2040% water by weight. Ball mills are employed in either primary or secondary grinding applications. In primary applications, they receive their feed from crushers, and in secondary applications, they receive their feed from rod mills, AG mills, or SAG mills.

Ball mills are filled up to 40% with steel balls (with 3080mm diameter), which effectively grind the ore. The material that is to be ground fills the voids between the balls. The tumbling balls capture the particles in ball/ball or ball/liner events and load them to the point of fracture.

When hard pebbles rather than steel balls are used for the grinding media, the mills are known as pebble mills. As mentioned earlier, pebble mills are widely used in the North American taconite iron ore operations. Since the weight of pebbles per unit volume is 3555% of that of steel balls, and as the power input is directly proportional to the volume weight of the grinding medium, the power input and capacity of pebble mills are correspondingly lower. Thus, in a given grinding circuit, for a certain feed rate, a pebble mill would be much larger than a ball mill, with correspondingly a higher capital cost. However, the increase in capital cost is justified economically by a reduction in operating cost attributed to the elimination of steel grinding media.

In general, ball mills can be operated either wet or dry and are capable of producing products in the order of 100m. This represents reduction ratios of as great as 100. Very large tonnages can be ground with these ball mills because they are very effective material handling devices. Ball mills are rated by power rather than capacity. Today, the largest ball mill in operation is 8.53m diameter and 13.41m long with a corresponding motor power of 22MW (Toromocho, private communications).

Planetary ball mills. A planetary ball mill consists of at least one grinding jar, which is arranged eccentrically on a so-called sun wheel. The direction of movement of the sun wheel is opposite to that of the grinding jars according to a fixed ratio. The grinding balls in the grinding jars are subjected to superimposed rotational movements. The jars are moved around their own axis and, in the opposite direction, around the axis of the sun wheel at uniform speed and uniform rotation ratios. The result is that the superimposition of the centrifugal forces changes constantly (Coriolis motion). The grinding balls describe a semicircular movement, separate from the inside wall, and collide with the opposite surface at high impact energy. The difference in speeds produces an interaction between frictional and impact forces, which releases high dynamic energies. The interplay between these forces produces the high and very effective degree of size reduction of the planetary ball mill. Planetary ball mills are smaller than common ball mills, and are mainly used in laboratories for grinding sample material down to very small sizes.

Vibration mill. Twin- and three-tube vibrating mills are driven by an unbalanced drive. The entire filling of the grinding cylinders, which comprises the grinding media and the feed material, constantly receives impulses from the circular vibrations in the body of the mill. The grinding action itself is produced by the rotation of the grinding media in the opposite direction to the driving rotation and by continuous head-on collisions of the grinding media. The residence time of the material contained in the grinding cylinders is determined by the quantity of the flowing material. The residence time can also be influenced by using damming devices. The sample passes through the grinding cylinders in a helical curve and slides down from the inflow to the outflow. The high degree of fineness achieved is the result of this long grinding procedure. Continuous feeding is carried out by vibrating feeders, rotary valves, or conveyor screws. The product is subsequently conveyed either pneumatically or mechanically. They are basically used to homogenize food and feed.

CryoGrinder. As small samples (100 mg or <20 ml) are difficult to recover from a standard mortar and pestle, the CryoGrinder serves as an alternative. The CryoGrinder is a miniature mortar shaped as a small well and a tightly fitting pestle. The CryoGrinder is prechilled, then samples are added to the well and ground by a handheld cordless screwdriver. The homogenization and collection of the sample is highly efficient. In environmental analysis, this system is used when very small samples are available, such as small organisms or organs (brains, hepatopancreas, etc.).

The vibratory ball mill is another kind of high-energy ball mill that is used mainly for preparing amorphous alloys. The vials capacities in the vibratory mills are smaller (about 10 ml in volume) compared to the previous types of mills. In this mill, the charge of the powder and milling tools are agitated in three perpendicular directions (Fig. 1.6) at very high speed, as high as 1200 rpm.

Another type of the vibratory ball mill, which is used at the van der Waals-Zeeman Laboratory, consists of a stainless steel vial with a hardened steel bottom, and a single hardened steel ball of 6 cm in diameter (Fig. 1.7).

The mill is evacuated during milling to a pressure of 106 Torr, in order to avoid reactions with a gas atmosphere.[44] Subsequently, this mill is suitable for mechanical alloying of some special systems that are highly reactive with the surrounding atmosphere, such as rare earth elements.

A ball mill is a relatively simple apparatus in which the motion of the reactor, or of a part of it, induces a series of collisions of balls with each other and with the reactor walls (Suryanarayana, 2001). At each collision, a fraction of the powder inside the reactor is trapped between the colliding surfaces of the milling tools and submitted to a mechanical load at relatively high strain rates (Suryanarayana, 2001). This load generates a local nonhydrostatic mechanical stress at every point of contact between any pair of powder particles. The specific features of the deformation processes induced by these stresses depend on the intensity of the mechanical stresses themselves, on the details of the powder particle arrangement, that is on the topology of the contact network, and on the physical and chemical properties of powders (Martin et al., 2003; Delogu, 2008a). At the end of any given collision event, the powder that has been trapped is remixed with the powder that has not undergone this process. Correspondingly, at any instant in the mechanical processing, the whole powder charge includes fractions of powder that have undergone a different number of collisions.

The individual reactive processes at the perturbed interface between metallic elements are expected to occur on timescales that are, at most, comparable with the collision duration (Hammerberg et al., 1998; Urakaev and Boldyrev, 2000; Lund and Schuh, 2003; Delogu and Cocco, 2005a,b). Therefore, unless the ball mill is characterized by unusually high rates of powder mixing and frequency of collisions, reactive events initiated by local deformation processes at a given collision are not affected by a successive collision. Indeed, the time interval between successive collisions is significantly longer than the time period required by local structural perturbations for full relaxation (Hammerberg et al., 1998; Urakaev and Boldyrev, 2000; Lund and Schuh, 2003; Delogu and Cocco, 2005a,b).

These few considerations suffice to point out the two fundamental features of powder processing by ball milling, which in turn govern the MA processes in ball mills. First, mechanical processing by ball milling is a discrete processing method. Second, it has statistical character. All of this has important consequences for the study of the kinetics of MA processes. The fact that local deformation events are connected to individual collisions suggests that absolute time is not an appropriate reference quantity to describe mechanically induced phase transformations. Such a description should rather be made as a function of the number of collisions (Delogu et al., 2004). A satisfactory description of the MA kinetics must also account for the intrinsic statistical character of powder processing by ball milling. The amount of powder trapped in any given collision, at the end of collision is indeed substantially remixed with the other powder in the reactor. It follows that the same amount, or a fraction of it, could at least in principle be trapped again in the successive collision.

This is undoubtedly a difficult aspect to take into account in a mathematical description of MA kinetics. There are at least two extreme cases to consider. On the one hand, it could be assumed that the powder trapped in a given collision cannot be trapped in the successive one. On the other, it could be assumed that powder mixing is ideal and that the amount of powder trapped at a given collision has the same probability of being processed in the successive collision. Both these cases allow the development of a mathematical model able to describe the relationship between apparent kinetics and individual collision events. However, the latter assumption seems to be more reliable than the former one, at least for commercial mills characterized by relatively complex displacement in the reactor (Manai et al., 2001, 2004).

A further obvious condition for the successful development of a mathematical description of MA processes is the one related to the uniformity of collision regimes. More specifically, it is highly desirable that the powders trapped at impact always experience the same conditions. This requires the control of the ball dynamics inside the reactor, which can be approximately obtained by using a single milling ball and an amount of powder large enough to assure inelastic impact conditions (Manai et al., 2001, 2004; Delogu et al., 2004). In fact, the use of a single milling ball avoids impacts between balls, which have a remarkable disordering effect on the ball dynamics, whereas inelastic impact conditions permit the establishment of regular and periodic ball dynamics (Manai et al., 2001, 2004; Delogu et al., 2004).

All of the above assumptions and observations represent the basis and guidelines for the development of the mathematical model briefly outlined in the following. It has been successfully applied to the case of a Spex Mixer/ Mill mod. 8000, but the same approach can, in principle, be used for other ball mills.

The Planetary ball mills are the most popular mills used in MM, MA, and MD scientific researches for synthesizing almost all of the materials presented in Figure 1.1. In this type of mill, the milling media have considerably high energy, because milling stock and balls come off the inner wall of the vial (milling bowl or vial) and the effective centrifugal force reaches up to 20 times gravitational acceleration.

The centrifugal forces caused by the rotation of the supporting disc and autonomous turning of the vial act on the milling charge (balls and powders). Since the turning directions of the supporting disc and the vial are opposite, the centrifugal forces alternately are synchronized and opposite. Therefore, the milling media and the charged powders alternatively roll on the inner wall of the vial, and are lifted and thrown off across the bowl at high speed, as schematically presented in Figure 2.17.

However, there are some companies in the world who manufacture and sell number of planetary-type ball mills; Fritsch GmbH (www.fritsch-milling.com) and Retsch (http://www.retsch.com) are considered to be the oldest and principal companies in this area.

Fritsch produces different types of planetary ball mills with different capacities and rotation speeds. Perhaps, Fritsch Pulverisette P5 (Figure 2.18(a)) and Fritsch Pulverisette P6 (Figure 2.18(b)) are the most popular models of Fritsch planetary ball mills. A variety of vials and balls made of different materials with different capacities, starting from 80ml up to 500ml, are available for the Fritsch Pulverisette planetary ball mills; these include tempered steel, stainless steel, tungsten carbide, agate, sintered corundum, silicon nitride, and zirconium oxide. Figure 2.19 presents 80ml-tempered steel vial (a) and 500ml-agate vials (b) together with their milling media that are made of the same materials.

Figure 2.18. Photographs of Fritsch planetary-type high-energy ball mill of (a) Pulverisette P5 and (b) Pulverisette P6. The equipment is housed in the Nanotechnology Laboratory, Energy and Building Research Center (EBRC), Kuwait Institute for Scientific Research (KISR).

Figure 2.19. Photographs of the vials used for Fritsch planetary ball mills with capacity of (a) 80ml and (b) 500ml. The vials and the balls shown in (a) and (b) are made of tempered steel agate materials, respectively (Nanotechnology Laboratory, Energy and Building Research Center (EBRC), Kuwait Institute for Scientific Research (KISR)).

More recently and in year 2011, Fritsch GmbH (http://www.fritsch-milling.com) introduced a new high-speed and versatile planetary ball mill called Planetary Micro Mill PULVERISETTE 7 (Figure 2.20). The company claims this new ball mill will be helpful to enable extreme high-energy ball milling at rotational speed reaching to 1,100rpm. This allows the new mill to achieve sensational centrifugal accelerations up to 95 times Earth gravity. They also mentioned that the energy application resulted from this new machine is about 150% greater than the classic planetary mills. Accordingly, it is expected that this new milling machine will enable the researchers to get their milled powders in short ball-milling time with fine powder particle sizes that can reach to be less than 1m in diameter. The vials available for this new type of mill have sizes of 20, 45, and 80ml. Both the vials and balls can be made of the same materials, which are used in the manufacture of large vials used for the classic Fritsch planetary ball mills, as shown in the previous text.

Retsch has also produced a number of capable high-energy planetary ball mills with different capacities (http://www.retsch.com/products/milling/planetary-ball-mills/); namely Planetary Ball Mill PM 100 (Figure 2.21(a)), Planetary Ball Mill PM 100 CM, Planetary Ball Mill PM 200, and Planetary Ball Mill PM 400 (Figure 2.21(b)). Like Fritsch, Retsch offers high-quality ball-milling vials with different capacities (12, 25, 50, 50, 125, 250, and 500ml) and balls of different diameters (540mm), as exemplified in Figure 2.22. These milling tools can be made of hardened steel as well as other different materials such as carbides, nitrides, and oxides.

Figure 2.21. Photographs of Retsch planetary-type high-energy ball mill of (a) PM 100 and (b) PM 400. The equipment is housed in the Nanotechnology Laboratory, Energy and Building Research Center (EBRC), Kuwait Institute for Scientific Research (KISR).

Figure 2.22. Photographs of the vials used for Retsch planetary ball mills with capacity of (a) 80ml, (b) 250ml, and (c) 500ml. The vials and the balls shown are made of tempered steel (Nanotechnology Laboratory, Energy and Building Research Center (EBRC), Kuwait Institute for Scientific Research (KISR)).

Both Fritsch and Retsch companies have offered special types of vials that allow monitoring and measure the gas pressure and temperature inside the vial during the high-energy planetary ball-milling process. Moreover, these vials allow milling the powders under inert (e.g., argon or helium) or reactive gas (e.g., hydrogen or nitrogen) with a maximum gas pressure of 500kPa (5bar). It is worth mentioning here that such a development made on the vials design allows the users and researchers to monitor the progress tackled during the MA and MD processes by following up the phase transformations and heat realizing upon RBM, where the interaction of the gas used with the freshly created surfaces of the powders during milling (adsorption, absorption, desorption, and decomposition) can be monitored. Furthermore, the data of the temperature and pressure driven upon using this system is very helpful when the ball mills are used for the formation of stable (e.g., intermetallic compounds) and metastable (e.g., amorphous and nanocrystalline materials) phases. In addition, measuring the vial temperature during blank (without samples) high-energy ball mill can be used as an indication to realize the effects of friction, impact, and conversion processes.

More recently, Evico-magnetics (www.evico-magnetics.de) has manufactured an extraordinary high-pressure milling vial with gas-temperature-monitoring (GTM) system. Likewise both system produced by Fritsch and Retsch, the developed system produced by Evico-magnetics, allowing RBM but at very high gas pressure that can reach to 15,000kPa (150bar). In addition, it allows in situ monitoring of temperature and of pressure by incorporating GTM. The vials, which can be used with any planetary mills, are made of hardened steel with capacity up to 220ml. The manufacturer offers also two-channel system for simultaneous use of two milling vials.

Using different ball mills as examples, it has been shown that, on the basis of the theory of glancing collision of rigid bodies, the theoretical calculation of tPT conditions and the kinetics of mechanochemical processes are possible for the reactors that are intended to perform different physicochemical processes during mechanical treatment of solids. According to the calculations, the physicochemical effect of mechanochemical reactors is due to short-time impulses of pressure (P = ~ 10101011 dyn cm2) with shift, and temperature T(x, t). The highest temperature impulse T ~ 103 K are caused by the dry friction phenomenon.

Typical spatial and time parameters of the impactfriction interaction of the particles with a size R ~ 104 cm are as follows: localization region, x ~ 106 cm; time, t ~ 108 s. On the basis of the obtained theoretical results, the effect of short-time contact fusion of particles treated in various comminuting devices can play a key role in the mechanism of activation and chemical reactions for wide range of mechanochemical processes. This role involves several aspects, that is, the very fact of contact fusion transforms the solid phase process onto another qualitative level, judging from the mass transfer coefficients. The spatial and time characteristics of the fused zone are such that quenching of non-equilibrium defects and intermediate products of chemical reactions occurs; solidification of the fused zone near the contact point results in the formation of a nanocrystal or nanoamor- phous state. The calculation models considered above and the kinetic equations obtained using them allow quantitative ab initio estimates of rate constants to be performed for any specific processes of mechanical activation and chemical transformation of the substances in ball mills.

There are two classes of ball mills: planetary and mixer (also called swing) mill. The terms high-speed vibration milling (HSVM), high-speed ball milling (HSBM), and planetary ball mill (PBM) are often used. The commercial apparatus are PBMs Fritsch P-5 and Fritsch Pulverisettes 6 and 7 classic line, the Retsch shaker (or mixer) mills ZM1, MM200, MM400, AS200, the Spex 8000, 6750 freezer/mill SPEX CertiPrep, and the SWH-0.4 vibrational ball mill. In some instances temperature controlled apparatus were used (58MI1); freezer/mills were used in some rare cases (13MOP1824).

The balls are made of stainless steel, agate (SiO2), zirconium oxide (ZrO2), or silicon nitride (Si3N). The use of stainless steel will contaminate the samples with steel particles and this is a problem both for solid-state NMR and for drug purity.

However, there are many types of ball mills (see Chapter 2 for more details), such as drum ball mills, jet ball mills, bead-mills, roller ball mills, vibration ball mills, and planetary ball mills, they can be grouped or classified into two types according to their rotation speed, as follows: (i) high-energy ball mills and (ii) low-energy ball mills. Table 3.1 presents characteristics and comparison between three types of ball mills (attritors, vibratory mills, planetary ball mills and roller mills) that are intensively used on MA, MD, and MM techniques.

In fact, choosing the right ball mill depends on the objectives of the process and the sort of materials (hard, brittle, ductile, etc.) that will be subjecting to the ball-milling process. For example, the characteristics and properties of those ball mills used for reduction in the particle size of the starting materials via top-down approach, or so-called mechanical milling (MM process), or for mechanically induced solid-state mixing for fabrications of composite and nanocomposite powders may differ widely from those mills used for achieving mechanically induced solid-state reaction (MISSR) between the starting reactant materials of elemental powders (MA process), or for tackling dramatic phase transformation changes on the structure of the starting materials (MD). Most of the ball mills in the market can be employed for different purposes and for preparing of wide range of new materials.

Martinez-Sanchez et al. [4] have pointed out that employing of high-energy ball mills not only contaminates the milled amorphous powders with significant volume fractions of impurities that come from milling media that move at high velocity, but it also affects the stability and crystallization properties of the formed amorphous phase. They have proved that the properties of the formed amorphous phase (Mo53Ni47) powder depends on the type of the ball-mill equipment (SPEX 8000D Mixer/Mill and Zoz Simoloter mill) used in their important investigations. This was indicated by the high contamination content of oxygen on the amorphous powders prepared by SPEX 8000D Mixer/Mill, when compared with the corresponding amorphous powders prepared by Zoz Simoloter mill. Accordingly, they have attributed the poor stabilities, indexed by the crystallization temperature of the amorphous phase formed by SPEX 8000D Mixer/Mill to the presence of foreign matter (impurities).

mill trunnion liner

This worm acts like an auger or a screw. As the mill turns the spiral will pull the feed into the mill. Part of the feed chute will be a seal between itself and the mill. This seal is required to prevent spillage.

It is in the form of a plate with a circular hole cut in the centre of it. The seal is bolted over the end of the trunnion liner. This is to allow the feed chute to come down through this hole into the mill. The material that forms the seal will be attached around the hole. It may be made from rubber Teflon or maybe just plywood. The other half of the seal is connected to the feed chute. When the chute is in place the two halves of the seal come together holding the solids in the mill. This seal requires a fair amount of attention and up keep. With one half of the seal moving and the other half stationary, any grit and small rocks that get into the seal will cause a great deal of friction. This will wear the seal out rather quickly.

In most cases the trunnion liners are already mounted in the trunnions of the mills. If not, they should be assembled with attention being given to match marks or in some cases to dowel pins which are used to locate the trunnion liners in their proper relation to other parts.

Assemble the oil seal with the spring in place, and with the split at the top. Encircle the oil seal with the band, keeping the blocks on the side of the bearing at or near the horizontal center line so that when in place they will fit between the two dowel pins on the bearing, which are used to prevent rotation of the seal.

Moderately tighten up the cap screws at the blocks, pulling them together to thus hold the seal with its spring in place. If the blocks cannot be pulled snuggly together, then the oil seal may be cut accordingly. Oil the trunnion surface and slide the entire seal assembly back into place against the shoulder of the bearing and finish tightening. Install the retainer ring and splash ring as shown.

If a scoop feeder, combination drum scoop feeder or drum feeder is supplied with the mill, it should be mounted on the extended flange of the feed trunnion liner, matching the dowel pin with its respective hole. The dowel pin arrangement is provided only where there is a spiral in the feed trunnion liner. This matching is important as it fixes the relationship between the discharge from the scoop and the internal spiral of the trunnion liner. Tighten the bolts attaching the feeder to the trunnion liner evenly, all around the circle, seating the feeder tightly and squarely on its beveled seat. Check the belts holding the tips and other bolts that may reduce tightening. The beveled seat design is used primarily where a feeder is provided for the trunnion to trunnion liner connection, and the trunnion liner to feeder connection. When a feeder is not used these connecting joints are usually provided by a simple cylindrical or male and female joints. If a spout feeder is to be used, it is generally supplied by the user, and should be mounted independently of the mill. The spout should protect inside the feed trunnion liner, but must not touch the liner or spiral.

Ordinarily the feed box for a scoop feeder is designed and supplied by the user. The feed box should be so constructed that it has at least 6 clearance on both sides and at the bottom of the scoop. The clearance is measured from the outside of the feed scope. The feed box may be constructed of 2 wood, but more often is made of 3/16 or plate steel reinforced with angles. In the larger size mills, the lower portion is sometimes made of concrete. Necessary openings should be provided for the original feed and the sand returns from the classifiers when in closed circuit. Horizontal and vertical joints should be provided for maintenance of the feeder. These joints should be designed with consideration for head room and accessibility.

A plate steel gear guard is furnished with the mill for safety in operation and to protect the gear and pinion from dirt or grit. As soon as the gear and pinion have been cleaned and coated with the proper lubricant, the gear guard should be assembled and set on its foundation.

Wedoes not attempt to build a cheap grinding mill. Engineering based on long experience with mill manufacture enters into the production of BallMills, with the result that in field operation this equipment yields the lowest possible operating costs, maximum operating time, and years of useful service. As such then it is not an expensive mill.

Every Mill is engineered and designed to meet the specific grinding conditions under which it will be used. The speed of the mill, type of liners, grate openings for ball mills, size and type of feeder, size and type of bearings, trunnion openings, mill diameter and length, as well as many other smaller factors are all given careful consideration in designing the BallMill.

Each mill is of proper design, constructed in a workmanlike manner, and guaranteed to be free from defects in material or workmanship. All Ball Mills are built to jigs and templates so any part may be duplicated whenever required. All parts are accurately machined for fits with close tolerances. Before shipment each mill is assembled in our shops, carefully checked and match marked to facilitate field erection. The mill is given a heavy coat of paint especially prepared for this type of machinery and all machined surfaces are thoroughly coated with protecting grease.

A complete set of detailed drawings is made for each mill and kept in a fireproof vault. This assures the future supply of perfectly fitting replacement parts for the life of the mill. Wearing parts embodying the latest developments are supplied on all orders.

In these descriptions you will find the word MEEHANITE. This is a trade name for metal castings poured under a licensed agreement with The Meehanite Metal Corporation. A complete description of its characteristics and inherent nature is found on page 19.

Ball Mill shells are fabricated from rolled plate steel. Under special conditions they can be cast of Meehanite, steel, or special alloys. The plate steel shells are rolled accurately to diameter and are welded according to ASME specifications, using a Union Melt Automatic Welding Machine. This equipment provides an even flow, uniform strength weld with full penetration.

On each end of the shell are steel flange rings bored to fit the shell, set in place and welded to the shell inside and out by the Union Melt machine. Large diameter shells are stress relieved under temperature and atmosphere control after welding is completed. Such heat treatment relieves any stresses or strains set up during rolling and welding operations.

The method of attaching the flange rings leaves the inside surface of the shell free from any pockets or depressions which would cause pulp racing and wear. The flanges are then machined true with the shell axis and with each other and counterbored to gauge for male and female fit with the separate mill heads. This construction eliminates any possibility of bolt shearing.

Ball Mill shells are generally 5 to 7 greater in diameter than the nominal mill diameter figure. In other words the diameter of a ball Mill is the measurement inside the average thickness of new linersnot inside the shell as designated by some manufacturers.

Ball mill feed and discharge heads are detachable, cast of Meehanite metal of ample thickness, either of GA or GC, depending on the size of mill and with consideration to bending stresses. These heads are generally ribbed for extra strength and stiffness. Such ribs terminate near the center of the head in a trunnion seat. A male and female fit to the shell flange ring is provided and the back of the connecting flange is faced or spot faced to furnish a true seat for the joint connecting bolts.

The head to which the gear will be attached has a seat or flange with a shoulder turned accurately to size providing a seat for the gear. All turning and boring is done in one setting to assure perfect concentricity.

Smaller Ball Mills are constructed with separate trunnions; larger diameter mills have trunnions cast integral with the heads. Separate trunnions are attached to the heads with bolted flanges for male and female fit. Flanges are faced and counter bored. All trunnions are cast of Meehanite metal, turned and carefully polished. All trunnions have a large bearing surface capable of carrying the heavy mill load and to avoid heating during operation. The outer ends of the trunnions are faced and drilled to receive the trunnion liners, protecting the inside surface from wear. Liner bolt holes are drilled to template and spot faced on the outside of the head.

This head is of considerable depth providing a pulp lifting chamber, and is designed to contain the discharge grates, clamp bars, and the lifters which elevate the mill product through the trunnion. See pages 20 and 21.

For rod mill work the discharge head is conical in shape causing the rods to travel by rotation laterally and away from the exceptionally large discharge opening. The discharge opening is larger than the inlet opening, thus providing the ball millLow Pulp Line principle of grinding.

The feed end trunnion liner is also constructed of Meehanite and can be furnished of several designs to meet each specific application. For normal closed circuit grinding work a spiral liner is furnished to screw new feed and return sands into the mill. For spout fed mills a plain tapered liner is generally furnished.

The mill trunnions are machined with a taper bored seat to receive the trunnion liner. Such arrangement permits the trunnion liner weight to be carried by the seat rather than by the connecting studs. This is of particular importance on the feed end since the shearing effect of the added feeder would cause breakage of the feeder connecting bolts.

ball mill from mainly recycled parts : 11 steps - instructables

This is my first instructable and I will be showing you how to make a ball mill for grinding chemicals from some recycled washers/dryers and a few parts from your local hardware store.Please read all the way through the instructions before building to be sure you are capable of finishing it.This instructable was based on pictures from United Nuclear check it out http://www.unitednuclear.com/ballmill.htmThe finished product should look similar to this

Materials you will need --1. A motor -- I got one from a old dryer that is rated for around 1600 rpm which is good for this application.2. 2"x4" -- Amount will vary with the size of the mill.3. Pulleys(4) and Belts(2) -- Size will also vary. I was able to salvage mine from a old washer.4. Ball Bearings(4) -- You may be able to get some from old junk or buy the cheaply.5. Switch(1) -- Get a standard light switch.6. Wire nuts and electrical tape -- Hardware store.7. A rotatable wheel (optional but recommended) -- Like on the bottom of filing cabinets.8. A container -- Size will vary. 9. Two poles -- For shafts make sure to get them to fit inside of your ball bearings.It may seem like a daunting list of items but they are fairly inexpensive and you can salvage most of them or you may even have them laying around your house.

Find a old dryer, I happened to have one in the barn so I i ripped it apart. Sorry for no step by step images of the first parts but I was not planning on making this instructable at the time i removed it. The dryer you will want to get is a small one capable of plugging into a standard 3 prong 120v house outlet. If you cannot find one then you will just need to plug it into a 220v plug.You should be able to find how to get it out by yourself but i will do my best to talk you through it.1.) Turn the machine over and locate the screws on the bottom. (may be on side or back for different models.)2.) Take the screws out and unbolt the motor from the bottom panel and remove the panel.3.) When the motor is loose follow all the wires to the motor and pull any plugs on the motor to be able to remove the motor4.) With the motor removed find the power cord going to the machine and cut it off (you will need this later.)

Now its time to size up your machine. consider the following in the decision of the size 1.) Use (will you be using it for small batches of chemicals or large batches.) 2.) Area available (where will you be storing and using it)3.) Cost (Cost will vary with the size..generally the bigger the machine, the more it costs.)For this application I will be making the dimensions 2 ft wide by 1.5 ft long.1.) cut two pieces 2 ft long and two pieces 1' 2" long.2.) cut a piece 5 in long and another 7 inches long3.) screw them together using the guide shown

If possible mount it using preexisting mounting plate (how it was mounted in the machine) if it is not possible for example, the plate is on the bottom you can find another method.. I will cover a few in this step.For my motor I need another way of mounting because my mounting plate is not accessible. I will use metal straps to tension the motor down. Mount it in the shaded area shown in the picture.Depending on your motor, the pulley system will vary so use what is already there if possible.

Next, you need to mount your bearings for this application I am using metal straps and a couple screws to hold them in place. There are many ways these can be mounted so be creative. mount them in the shaded area in the first picture. The space between the sets of bearings and the motor will depend on the length of belts you have so be sure to compare it before you mount it.After the bearings are mounted, insert your shafts through the bearings so they extend out as shown in the second picture. be sure that when you pully is mounted on the shaft closest to the motor that it will line up or the belt other wise may slip.

Take the pullies and mount them on the ends of the shafts as shown in the picture (are you seeing a pattern?) then put the belts on between the pullies and make sure they are straight and make adjustments before moving on.

ok now on the motor there is a clip with three wires on mine one was black one was green and the third was blue (black=neg blue=hot green=ground) now cut the plug off and strip the three wires. Next strip the plug wire i told you to keep, revealing three wires mine were black white and green, strip them too and attach the black to the neg the green to the ground and the white to one of the switch terminals, then connect a wire from the other terminal to the hot wire on the motor being sure to wire nut and electrical tape all connections possible. you can mount the switch wherever you want.

For the shaft to properly spin the container it needs to be able to grip it metal on metal or plastic on metal just wont do. You can add grip by gluing any rubbery material around both shafts and container.

For the mill to work properly the chemicals and grinding media must collect in one area so the entire setup needs to be on a 30 degree angle so here we will add two legs to the base.this doesnt need much explanation just hold the front up (front being the way the motor is pointing) and measure 30 degrees and screw a leg on both sides.the angle is shown in the picture courtesy of united nuclear

This is optional but is highly recommended as it alows the container to rotate much smoother. cut another piece of wood that is 3/4 the diameter of your container and mount it as shown in the picture (the green box is where to mount it) pointing up forming a 90 degree angle with the base on each side. get a rotatable wheel like from a file cabinet and add it to the top of the new board to the container will hit against it.

Just set your container on the shafts add the chemical and right amount of grinding media and fire it up. If you find it is going to fast then gear it down by replacing the pulley on the end of the shaft that connects to the motor with a bigger one and if it goes to slow then use a smaller one to gear it up.Note: do not use more weight than the motor can handle and be safe using this following all guide lines and percautions found here http://www.skylighter.com/fireworks/how-to/use-a-ball-mill.aspThank you for reading this tutorial and leave comments plz

im 15 and want to make some pyrotechnic grade black powder for model rocketry purposes. is their a high saftey concern? what i mean is could it easily autoignite if i dropped a bottle of it or bumped it?

I'll start with this, please do not try to make black powder without the assistance of an adult with some working knowledge of chemistry. While making black powder is not the most dangerous thing to make, it is not hard to mess up and make it dangerous. That being said, I do have a moderate safety concern, however, if you get assistance it can be a great learning opportunity. And to answer your latter question, no black powder is not volatile enough to ignite from impact, however, it lights at a relatively low temperature; meaning that the smallest spark or flame has the ability to set it off. Please be safe and as always I take no responsibility for loss of life, limb, or money.

All of the above as jf78 said, plus BP is usually milled damp or wet which helps with the above issues, and is usually milled with leaden balls so that there is no chance of sparking. after milling, and while still a damp "paste" is the time to form it to the correct grain size for your purpose. The grains are then dried. Dry powder is (obviously) the most reactive/dangerous state.

In theory it would work but I see two problems. First, you would need to gear down the drill quiet a bit because a ball mill works better at a slower RPM. Second, I would be afraid a drill would start to overheat. A ball mill usually runs for hours and sometimes days on end, and drill motors aren't designed for that prolonged of use. But then again that is all my opinion. Let me know how it works if you try it.

Im sure it would work. You would get more power transfer than a belt and less chance of slipping. but on the downside it would probably be significantly more noisy and if you do go with this i would advise a guard over the chains so you dont lose fingers.

Use heater hose on the rods. It is durable, available at hardware and auto parts stores, and cheap. Spread some good Contact Cement or "Goop" on the rail before slipping it on. I also use sealed ball bearings on mine and needle thrust washers. They are a bit Expensive (try eBay or tear down burnt-out motors); but worth the less hassle. I rebuilt a regular tumbler that had plastic sleeve bearings that constantly wore out out or got a ring cut in them.

When ball milling, always use about 2/3 balls by volume. Make sure the drum isn't going too fast--say 2 revolutions per second, max. It helps to glue a couple of wooden "paddles" inside the drum to aid mixing. If the drum goes too fast, it will no longer tumble and drop the balls, but just throw things outward due to centrifugal force. Remember also to stop it , take out the drum and place it base-down, then open the lid a crack every couple days or so to vent it--don't let pressure build up.

On step 7 - ALWAYS switch the BLACK wire - in AC terms it is the 'hot' wire that goes from -110 to +110 volts. The white wire is neutral (zero volts)...meaning if you switch the hot wire, the circuit past the switch is 'dead' while off, but if you switch the white wire, the circuit will be live, just not connected - and you can get a nasty shock! This is why there is a polarized plug (with a fat prong and a narrow prong)

Motor might have a Red wire, or even yellow or orange, especially if you use a 220v/110v motor. Check the motor's label, if it has one. If not, google it. I have a nice dishwasher 1/2 HP motor, but it needs the starter hooked up to work, as in the appliance. The wiring diagram was available online. Try to use continuous-duty (Big) 1/-1/3 or so hP induction motors(ones without brushes). Drill motors are intermittent use only, and will burn out in a month of constant use.

Well written... but you really need to use your own pictures. From a construction standpoint... put all three pulleys on the same side. Then, construct a guard for the pulleys and belts. no more pinched fingers :-) you could even simplify and use a 2-step pulley for the first shaft.

ball mill, ball grinding mill - all industrial manufacturers - videos

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... LN2 feeding systems, jar and ball sizes, adapter racks, materials low LN2-consumption clearly structured user interface, memory for 9 SOPs programmable cooling and grinding cycles (10 ...

The XRD-Mill McCrone was specially developed for the preparation of samples for subsequent X-ray diffraction (XRD). The mill is used for applications in geology, chemistry, mineralogy and materials science, ...

The Planetary Ball Mill PM 200, engineered by Retsch, is a milling device best suited for mixing and size reduction processes and is also capable of meeting the necessary requirements for colloidal grinding ...

... Micro Mill PULVERISETTE 0 is the ideal laboratory mill for fine comminution of medium-hard, brittle, moist or temperature-sensitive samples dry or in suspension as well as for homogenising of emulsions ...

... , fast, effective. WORKING PRINCIPLE Impact and friction The FRITSCH Mini-Mill PULVERISETTE 23 grinds the sample through impact and friction between grinding balls and the inside wall of the grinding ...

... grinding mills includes being safe throughout. When the mills are quoted we make sure to include any and all safety components needed. Long life and minimum maintenance To help you get the most of your ...

Annular gap and agitator bead mills are used for processing suspensions and highly viscous products in chemicals and cosmetics as well as in the food sector. Studies have shown that annular gap bead ...

... Pneumatic extraction from the surface of the agitated media bed Wet grinding: Separation of suspension from the agitated media by ball retaining device Flexibility Through careful selection of the size and quantity ...

... details; Agitating power: 0,37 kW Total Power Consumption : 1.44 kW Total Weight : 100 kg Metal Ball Size : 6.35 mm Metal Ball Amount : 7 kg Cold water consumption : 10 liters / hour ...

Cement Ball Mill Processing ability: - 200 t/h Max feeding size: - 25 mm Product Fineness: - 0.074-0.89mm Range of application: - limestone, calcium carbonate, clay, dolomite and other minerals ...

... grinds and classifies a product. Vilitek MBL-NK-80 mill is specially designed for grinding valuable materials, which, when grinding, the re-milled fractions are not a commodity product. In particular, this mill ...

Dimensions: Height: 1530 mm Width: 650 mm Length : 1025 mm Description: Ball mills are capable of rapidly producing chocolate, nut pastes (for gianduia), and spreadable creams. It has been ...

the common failures of hammer crushers - jxsc machine

As important mining equipment for the underground coal mine coal transportation system, hammer crusher is usually installed in the middle section of the coal transportation system. Raw coal in the middle of the transportation is crushed into small pieces by a hammer crusher and then transported to the ground coal yard. The coal mine hammer crusher consists of the bottom trough, the crushing frame body, the breaker shaft, the transmission device, the adjusting device and the lubrication system. It has no transfer function and needs to be connected with the crushing bottom trough. The hammer crushing frame body is located at the upper part of the bottom groove, and a crusher shaft is installed in the middle of the frame body. Buy hammer crusher

The mechanism of action is that the broken hammer shaft is lifted to a certain height through the transmission device, thereby increasing the gravitational potential energy. After the falling, the hammer head impacts and squeezes the raw coal at the bottom groove, and is crushed to a smaller particle size, which is convenient for continuous transfer of the transfer machine. The coal mine hammer crusher can adopt two different transmission forms of pulley and reducer according to the power of the equipment. Normally, the pulley drive is only used for hammer crushers up to 250 kW, and hammer crushers larger than 250 kW are driven by reducers.

(1) Design processing defects. The design should ensure that the structure of the equipment is stable and the dynamic characteristics are good. Unreasonable mechanical construction will lead to local stress concentration in the hammer crushers, affecting the dynamic characteristics, and thus may cause undesirable phenomena such as forced vibration or self-excited vibration. (2) Installation, commissioning, and maintenance procedures. In the installation, commissioning and maintenance stages of the hammer crusher, the installation of each spare part may be misplaced. The coordination and installation positions of the shaft system in the transmission system are not suitable, the adjustment of the geometric parameters of the whole equipment is not in place, the installation position of the moving cone is unreasonable, etc., and then It may cause problems such as large equipment load and poor stability of the running state. (3) Human error. In the process of human operation, the equipment is abnormally opened, closed and the speed is not properly adjusted. The hammer crusher runs beyond the design working condition for a long time, the equipment lacks maintenance, and the lubrication between the various components is insufficient. It is also a factor causing the hammer crusher to malfunction. (4) Wear and deformation of the components. The hammer crusher runs for a long time, and various components are prone to different degrees of wear and deformation. Individual parts may be detached, cracked or even damaged by vibration, and the deflection of components such as moving cones may change. Parts may also be pitting or corroded by the external environment, or may wear out with other parts or be affected by vibration. Uneven settlement of the location; at the same time, the gap between the individual parts increases, the looseness of the fit, the friction of the mating surface decreases, etc., which will affect the normal operation of the hammer crushers.

The vibration and moving cone action of the hammer crusher will cause the moving cone to wear, which will cause the center of gravity of the moving cone to shift to form an eccentricity, resulting in an unbalanced moving cone. The problems caused by the imbalance of the hammer crushing motor cone are: (1) The moving cone produces an eccentricity, which changes the force state of the rotor to make it unevenly stressed. During the rotating motion, the moving cone repeatedly bends. When the fatigue limit is reached, damage or even breakage may occur. (2) The moving cone is unbalanced, the equipment is out of the design working condition, and the vibration is caused by severe vibration, which interferes with the external environment. (3) During the working process of the rotor, deflection due to uneven force, friction with bearings or other adjacent components not only causes wear of various components in the equipment, but also affects the working efficiency of the equipment. It is a serious safety hazard and should be strengthened. Inspection and timely disposal.

In a rotor system connected by a coupling, misalignment between the two rotors causes the coupling to deflect, and the bearing that is connected is affected by the rotor misalignment, which shortens the service life, affects the oil film stability of the sliding bearing, and the overall operation of the bearing. Poor, resulting in more serious irregular vibrations. The monitoring of rotor misalignment should be increased, and the vibration amplitude and phase stability should be detected.

The rotor system of the hammer crushers is affected by factors such as rotor misalignment, bending of the shaft, looseness of the foundation, wear of the bearing, improper assembly, etc., and friction or even rubbing phenomenon with the bearing. Although the torque that the rotor is subjected to during operation of the equipment can be balanced, the rotational speed is greatly affected, the rotor system is also unstable, and the overall stability of the equipment is degraded. Main performance: First, the rotor system vibrates, and second, the rubbing has an impact on the rotor itself. The two overlap each other, resulting in more complex adverse reactions, such as phase reverse displacement and axial trajectory diffusion or disorder. In the design stage, in order to ensure the stability of the equipment, the gap between the rotating parts and the adjacent parts is relatively small, and it is easier to increase the probability of occurrence of rubbing.

Hammer crusher is rotating vibration equipment. During operation, the ground bolts used for foundation and fixation vibrate, which can easily cause the foundation sinking and the loosening of the anchor bolt connection. At the same time, the bearing seat will also be loosened by the vibration. The vibration amplitude is larger, mainly in the vertical direction. In order to determine the loosening condition of the foundation and bearing seat, the vibration signals in the vertical direction are detected and compared with the vibration signals of crusher and ground bolt. If the foundation and bearing housing are looser, there will be a great difference between the two kinds of vibration signals, so it should be dealt with in time to avoid accidents.

Hammer crusher is the key equipment for crushing large blocks of raw coal in coal mine, and is an important part of the raw coal transportation system. Design and machining defects, installation, debugging, maintenance process problems and man-made operation errors and structural wear and tear, deformation is the main source of hammer crusher fault, moving cone imbalance, rotating shaft misalignment, rotor rubbing.

welcome to ghosh machinery allied products : products

This MACHINE has been specially designed for Voltage Testing of High Tension Porcelain Insulators. It is a continuous rotating mechanical device having 16/25 nos self-rotating sticks made of M.S.Pipe, mounted on a rotary table, 2400 mm dia and is driven by Motor and Compound Gear Box. Construction: The base frame of the machine is octagonal in shape and is made of sectional mild steel channel. The rotary Table is mounted on the base frame with a robust flange type boss fitted with two nos. heavy duty tapered roller bearings to enable the table to rotate freely. The upper end part of the stick is covered with the Backelite pipe and M.S. cap with copper chain, which is fitted at the top of the pipe.

This machine is suitable for Tensile Strength Testing of 8 nos. Disc insulators, with metal fittings at a time, complete with power operated Hydraulic unit, Max. 10 tones capacity. The chassis of the machine is fabricated from suitable channel and M.S.Plate. On the end side of the chassis fixed type tailstock is fitted with suitable clamp holding arrangement to hold Ball Pin, of the Disc Insulator. And with this disc one after another Disc will be connected on Wooden Table of the machine, and the last disc will be connected with the holder fitted with piston fitted on the headstock of the machine with Hydraulic Cylinder. On the side of the head stock power pack is situated complete with 1 HP Motor, Starter and Hydraulic equipment including pump for the hydraulic unit.

The body of the machine is fabricated from mild steel plate. Maximum 10 ton pressure can be given from Hydraulic Spring loaded Ram fitted with water circulation arrangement. Machine is complete with 3 HP motor, starter and power pack for the hydraulic arrangement.

This is a special type of Ball Mill with Auxillary Drive. This mill is water jacketed with hood suitable for dry grinding. Main drive with 75 H. P. motor, Fluid pulley to input shaft of helical gearbox, then with output shaft of the same gear coupling fitted with driving shaft. Auxillary Drive geared motor Fitted with extended input shaft of the helical gearbox coupled with one way clutch coupling.

In this drive arrangements, two starters are interlocked in such a way that by the help of a timer, after one or two revolution of the mill at slow speed (about 1 R.P.M.), the main motor starts automatically with simultaneous stoppage of auxillary drive. There is provision of starting auxillary drive individually for inching and positioning the mill shell. Generally this drive is used for production capacity of materials of 4 tones and above per charge.

This ball mill with belt reduction and V-Flat drive. Here at the time of final speed reduction belt is working as V-Flat drive. We also make drive with motor, fluid pulley to input shaft of helical gear box, then V pulley, fitted with the another shaft which is coupled with the outer shaft of the gear box fitted with bearings and plummer blocks. Then the same procedure is followed to the shell diameter.

We make blunger suitable for 200 liters to 20,000 liters capacity tank. Blungers are made with SS tank as per the picture. We are also making blunger's fabricated chassis housing fitted with shaft and impeller complete with driving arrangements suitable for concrete tank.

Our Diaphragm pumps are double acting type. We make two types of double acting pump, one is suitable for working in 12 Kg / Centimeter square pressure and capacity of free displacement is 3800 litres per hour and the other type is suitable for working in 15 / Kg Centimeter square and capacity of free displacement is 7600 litres per hour.

Filter press is designed with best technical know-how for processing of ceramic slip. Our capacity of machnice is from 500 Kg to 5000 Kg of cakes with 20/22% moisture content. We manufacture both hand operated closing device, controlled by man power and power operating closing device by hydraulic power. We supply machine complete with rubber cord, aluminium perfoarated sheet and filter cloth. Chamber plates of our machine are made from graded cast iron. We make complete chassis of the filter press, motorized hydraulic closing device when party wants to supply chamber plates. Technical Specification

This Pug Mill can Produce 3 ton clay blank dia of 300 mm with a vacumm reading of 720 mm hg and above. Of course it depends on the height of the place from sea-level, where the pugmill will work. On the top barrel of our machine two sets of augurs are there and one set in the lower barrel, augurs are made from Steel Casting/ Stainless Steel material. This pugmill is suitable for high tension insulator plants and table ware industries.

The production of PM 2 is 2500/3000 kg per hour of pugged blank. The maximun dia of pugged blank is 200 mm. A suitable vacumm pump is with the machine to get desired quality of clay blank. Steel casting / stainless steel casting augurs are used as per customers's specification. We are also making De-airing Pug mill Model PM 3. The production capcity of which is 250 Kg per hour. The Maximum diameter of pugged blank is 100 mm.

This machine is suitable for giving final inner shape of disk insulator type by the help of a rotating dye fitted with the spindle of the machine, which rotates giving up and down motion by the help of a cam fitted inside the body of the machine. The driving mechanism of the machine consisting of two geared motor and one gear box. Stroke/min-3, length of stroke-200 mm, max dia of mould that can rest on table-450 mm.

The process followed by this machine:- Shaped clay blank Kept in the plaster mould are loaded on the machine. Now the table starts moving (our table is 4 station type). There are two spindles rotating fitted with die. As soon as the mould with clay blank reaches just below the pre-shaping die table stops and pre-shaping die comes dowm and shapes the blank as per the pre-shaping die. Again the table starts rotating and stops just below the finishing die, then rotating die will come down and will give the inner shape of the insulator. Then the table rotates and stops. The operator will unload the mould with finished insulator and on the other side other operator will load the plaster mould with shaped clay blank. This process continues. The production of this machine is 3 nos. per minute.

GMAP is making two types of presses suitable for pressing shaped clay blank for keeping into plaster mould. This machine is used before giving preshaping or final shaping of disc type insulator. We are making two types of these machine model MP-1 and MP-2, stroke length 203-406 mm, stroke/min-19/20-19/20, Ram adjustment 100-100. Distance between column face and vertical axis of bumping mask 305-508 mm.

This copying model III is suitable for giving outer shape of clay blank of 1 meter long and 400 mm diameter. Inside the casting body of the machine, drive arrangement is their fitted with motor and gear box.

This machine is used for making hole in bushing type insulator. The machine is of two models. One for making hole directly in clay lump without any rotation of the hole making tool and other is made with arrangement for counter boring by means of rotation in the tool either in wet clay or leather hard or bone dry stage. The main spindle moves vertically along with the controlled distance as and when required by means of push button switch. Max dia of clay blank-400 mm, Max length of clay blank-800 mm.

Model V copying machine is suitable for clay blank with admit between centre 2000 mm long and 500 mm diameter. For holding clay blank hydralic device is there fitted with the tail stock of the machine. The upward and downward movement of tail stock can be controlled by the help of geared motor fitted with the machine which can be locked at any desired postion. Dynaspeed motor is driving the main chuck to achieve infinite variable motion of the chuck with clay blank. Manually operated smooth tool carriage is there which is capable of giving both vertical and horizontal motion of the knife which gives outer shape of the insulator as per template.

Copying-Boring Machine is suitable for 2000 mm long and 600 mm dia clay blank. Minimum 130 mm and maximum 280 mm bore can be done. Tapper and radius bore can also be done by the help of template fitted at the top of the machine. The boring arrangement of this machine is from the top. We also make Copying-Boring Machine suitable for 1 meter long X 400 mm dia and 1.5 meter long x 500 mm dia clay blank.

Standard copying machine is suitable for giving outer shape of 11 KV pin, Post, Bushing similar type of insulators.By the help of this machine we can give the outer shape of other small insulator by using suitable tools and profiles.

Structure of the machine will be fabricated from Steel Plate. Heavy type 2 nos. EN-24, chromium plated, grinding finished ram is fitted with 4 nos. linear Bearing (SKF MAKE) for movement of carriage including holding arrangement for mould complete with 10 H.P. Geared motor (Power Build Make). RPM of the die is 10-100 (Infinite variable arragement with A.C. Drive Voltage Frequency System, YASKAWA/L&T MAKE). The machine will be complete with Hydralic arrangement, power pack (with 10 H.P. 1440 RPM Motor) & Electric Control Panel Board with necessary timer, gadgets etc.

This machine is designed for cementing caps on disc insulator at a faster rate, in which centrality of cap with disc is always maintained which is not possible by manual process. Applying moist cement inside metal caps mechanical device holds the cap and then by pneumatic upward movement disc comes in just pressing contact with cap and gets connected in a preset duration, which is controlled by a electrically operated timer. There are two Pneumatic cylinders in the machine (air pressure required - Max 10 K.G per centimeter square)with neccessary valves and electricals.

This machine is suitable for cementing ball pin in the Disc Insulator. Arrangements are there for cementing Ball Pin with 6 nos. Disc type insulator at a time. The spring fitted Table give vibration by the help of a 1 H.P. 2880 R.P.M motor with eccentric load.

The Mangle Drier is suitable for drying disc Insulators placed on moulds upto a maximum temperature from 45 degree centigrade minimum to to maximum of 70 degree centigrade. Description : The Mangle Drier consists of the following:-

Description : Trollies are used in ceramic factories for handling as well as natural drying the ceramic articles. GMAP designed sophicated trolley which is called Steering Drying Car has a better,easy operated directional steering which can bear heavy load and pull as well. By testing it has been proved that it is strong enough to bear even 800 kg. load. The rail cum floor type wheels are provided so that it can move on thr floor and narrow jauge rail. Hence those who are having tunnel type dryer they can simply push the car in the tunnel drier with loaded decks. The wheels have been rubberised in such a way that the car, when operated on floor, can withstand temperature upto 140 degree centigrade and when put on rail the rubberised portion remains free while the metal portion comes in contact with rail. The additional advantage of car is to minimise the accommodation problem as the car is having provision for 5 Nos. to 6 Nos. deck to be easily fitted with planks or other substance upon which the articles are placed for the purpose of drying which resembles to a mobile room in the factory. Construction: The car is made with mild steel (IS 226) angle and channel of broad section. The axles are made of steel fitted with 8 Nos. ball bearing which help to move the car freely. The wheels are made of well proportioned cast iron and it is properly rubberised under the catching of dovetail groves which ensures and strengthen hold of rubber on the wheel. A good steering with handle is provided to turn the car on 180 degree angle very smoothly.

We make blunger suitable for 200 liters to 20,000 liters capacity tank. Blungers are made with SS tank as per the picture. We are also making blunger's fabricated chassis housing fitted with shaft and impeller complete with driving arrangements suitable for concrete tank.

Description: GMW Screw Blunger used for dissolving clay in water, also for mixing and stirring all types of ceramic slip and glazes, as well as mixing and stirring all other materials in paper, paints and chemical industries etc. Method of Operation: The High Speed BLUNGER having three blades (ship propeller type) immersed in the slip and continuosly circulates the contents of the octagonal vat in vertical direction. The V-shaped bottom of the octagonal vat assists the circulation whereby the materials in lump form are dissolved or mixed with the other constituents at high speed. Construction: GMW Screw Blunger main driving shaft is made out of EM8 steel and fitted with C. I. bearing housing and mounted on well ribbed fabricated M. S. frame constituting the blunger unit. The whole of the blunger unit can be mounted on the rim of the Vat. Normally, Vats are made from M. S. plastic coated or concrete construction. BLUNGER SHAFT is connected by means of flanged coupling to main driving shaft. Specifications of our standard products are given below. Large size or special screw blunger can be manufactured as per customer's requirement. Drive: GMW Blunger is driven by means of V-belt drive arrangement or Worm speed reducer with chain sprocket.

This machine is designed to dip insulator in the Glaze bath automatically. The machine consists of 16 to 25 nos dipping arms rotating with the rotation of the housing shaft. The driving arrangement of the machine are one hp motor and one compound gear box suitable for getting 6 rpm to the housing shaft. Production of this machine is 500 to 700 nos of insulators per hour.