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 .
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 . 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 .
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 . 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. 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. and El-Eskandarany etal. 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. 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, using for example cold-rolling approach, 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.
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).
Cotton today is the most used textile fiber in the world. Its current market share is 56 percent for all fibers used for apparel and home furnishings and sold in the U.S. Another contribution is attributed to nonwoven textiles and personal care items. The earliest evidence of using cotton is from India and the date assigned to this fabric is 3000 B.C. There were also excavations of cotton fabrics of comparable age in Southern America. Cotton cultivation first spread from India to Egypt, China, and the South Pacific.
Cotton is a soft, staple fiber that grows in a form known as a boll around the seeds of the cotton plant, a shrub native to tropical and subtropical regions around the world, including the Americas, India, and Africa. The fiber most often is spun into yarn or thread and used to make a soft, breathable textile, which is the most widely used natural-fiber cloth in clothing today. The English name derives from the Arabic (al) qutn , which began to be used circa 1400.
Cotton is a soft fiber that grows around the seeds of the cotton plant. Cotton fiber grows in the seed pod or boll of the cotton plant. Each fiber is a single elongated cell that is flat twisted and ribbon-like with a wide inner hollow (lumen).
Cotton is a natural fiber that is grown in countries around the world. It is a crop that requires adequate moisture and heat to mature and produce quality fibers. Cotton growing tends to be in warmer climates. Cotton is a true commodity in the world markets and supply and demand truly affect prices of raw cotton.
Cotton fibers are mainly made up of cellulose. Cellulose does not form unless temperatures are over 70 F (21 C). The cotton fibers are attached to the seeds inside the boll of the plant. There are usually six or seven seeds in a boll and up to 20,000 fibers attached to each seed. The length of these fibers (also called staples) is the main determining factor in the quality of the cotton. In general, the longer the staple grows the higher the quality of the cotton. Staple lengths are divided into short, medium, and long (and extra long, in some cases):
Long staple cotton is considered to be finer quality because they can be spun into finer yarns and those finer yarns can be woven into softer, smoother, stronger, and more lustrous fabrics. Long staple cotton makes stronger yarns, especially in fine yarns, as there are fewer fibers in a given length of yarn and the longer fibers provide more points of contact between the fibers when they are twisted together in the spinning process.
Common areas that grow long staple cotton in the world would be Egypt, Sudan, the United States (Pima cotton grown in the west and southwest are long staple cotton), and Western China. The two most widely known long-staple cottons are Egyptian cotton and Pima cotton. Pima cotton is grown mainly in the United States, but also in Peru, Israel, and Australia.
The fibers are sent to a textile mill where carding machines turn the fibers into cotton yarn. The yarns are woven into cloth that is comfortable and easy to wash but does wrinkle easily. Cotton fabric will shrink about 3% when washed unless pre-treated to resist shrinking.
Harvesting machines called strippers and pickers efficiently remove the cotton while leaving the plants undisturbed. Spindle harvester, also called a picker, has drums with spindles that pull the cotton from the boll in one or two rows at a time. Even a one-row mechanical picker can do the work formerly done by 40 hand pickers.
Cotton buyers judge cotton on the basis of samples cut from the bales. Skilled cotton classers grade or class the cotton according to standards established by the US Department of Agriculture such as cleanliness, the degree of whiteness, length of the fiber, and fiber strength.
The classes pull a sample. They discard most of the cotton until just a pinch of well-aligned fibers remains. They measure the length of the fibers, referred to as staple fibers. Longer staple fibers are higher-grade cotton and are sold at higher prices. Long staples range from 1.1 inches to 1.4 inches long.
From the field, seed cotton moves to nearby gins for separation of lint and seed. The cotton first goes through dryers to reduce moisture content and then through cleaning equipment to remove foreign matter. These operations facilitate processing and improve fiber quality. The cotton is then air conveyed to gin stands where revolving circular saws pull the lint through closely spaced ribs that prevent the seed from passing through. The lint is removed from the saw teeth by air blasts or rotating brushes and then compressed into bales weighing approximately 500 pounds. Cotton is then moved to a warehouse for storage until it is shipped to a textile mill for use.
Cotton is a natural fabric that is very versatile and comfortable. It is generally soft to touch, making it ideal for people with sensitive skin or skin allergies. It is also very breathable, which means it makes sweat wick off your skin. This keeps you cool and comfortable even during summer. Stephen Cardino, who has been the home fashion director at Macys for 7 years and is a 25-year veteran of the bedding industry, weighs in on what you need to know to be certain when youre picking only the best cotton bed sheets.
hey I have a question and i was hoping you could help. I work with patients in wound care and lymphedema. I use Comprilan and Rosidal k a lot for my patients. These bandages advertise 100% cotton but seem to have incredible elastomeric properties What material allows this elasticity? How can this be 100% cotton.??????
As such cotton does have high elasticity not more than 10%. If the fabric is getting stretched more than that but around 20% it can with modified fabric and yarn construction like higher twist in yarn. If suppose elasticity is further more, then it can be other fibre like Nylon (one man made fibre). In case of cotton fabric elasticity is enhanced around 30 to 200% with the addition of Lycra filament (ranging 4-10% by weight) during fabric or yarn manufacturing. This you can see in socks, elastic knitted fabric and cotton stretchable elastic jeans. In that case it is specificaly mentioned Lycra % on fabric garment. In such fabric if you open yarn from fabric you will find very tinny white filament i.e Lycra filament (like synthetic rubber- 3-4 time elasticity).
Textile School incorporates knowledge associated to textiles right from fibers to its end usage including textile processes, trade-offs, know-how and textile standards. The site is intended for all spectrum of users to learn and share the textile knowledge from a single platform.
Cement Plant Features: 1) Model: B300,B400,B600,B1000,B2000,B3000,B3350,B5000,B10000 2) Production capacity: 300~10,000MT/day 3) Limestone crusher 4) Raw materials mill 5) Preheater tower 6) Burn...
Cement Plant Features: 1) Model: B300,B400,B600,B1000,B2000,B3000,B3350,B5000,B10000 2) Production capacity: 300~10,000MT/day 3) Limestone crusher 4) Raw materials mill 5) Preheater tower 6) Burn...
A line (semi-automatic plant) consists of automatic batching,mixing and press system,manual transferring and stacking system with natural curing(or elevator/lowerator/stacker) B line (fully automatic ...
Block making flow chart: 1. Brick raw materials should be prepared. Such as clay, fly ash, coal gangue, shale and so on. 2. Brick factory should be built. The yard of brick plant should be i...
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A line (semi-automatic plant) consists of automatic batching,mixing and press system,manual transferring and stacking system with natural curing(or elevator/lowerator/stacker) B line (fully automatic ...
The batches for mixing the Raw Materials are weighed electronically so that precise quantities are supplied for mixing. Our company uses Dispersion Kneader and Mixing Mills to ensure, the required quality of the rubber compound, to be used in the manufacturing process.
1t/h-2t/h small animal feed manufacturing process is specially designed for meeting the demand from our clients, which can process the animal feed pellets with the size varying from 1.5 mm to 18 mm based on the requirement of the customers. It is mainly used for making animal feed pellets on cattle or poultry farms, in small animal feed factories, and for invetors to start animal feed business.
As one professional animal feed manufacturing equipment manufacturer and supplier, ABC Machinery can not only offer the small scale animal feed process, but also provides turkey feed milling project plan for making animal feed pellets, mash feed and crumble feed with multiple sizes.(Read more: small cattle feed manfuacturing plant >>)
The 1-2 ton per hour animal feed production plant is specially designed and manufactured for one of our clients, which is suitable for producing both poultry feed and livestock feed, including cattle, sheep, cow, pig, birds etc., while some equipment choices may vary. Before running your own animal feed production plant, view the factory layout of this small feed processing plant for reference. Here is the main necessary equipment for the small animal feed processing plant. (Read more: chicken feed production process>>)
If you are a farmer and want to buy a small chicken feed making machine for your own use. Welcome to contact us to get a complete and customized animal feed manufacturing business plan with detailed cost information!
The manufacturing process of animal feed can be divided into several stages, and there is one specialized feed processing equipment for each stage of the production process. According to the raw materials conditions, the making process can be added or reduced, we customize the production line for our clients! (Related article:5ton/h animal feed plant layout and design>>)
The crushed fodder materials are then passed through a feed mixing machine, where different ingredients are added to the feed raw material to ensure that the finished pellet contains all the required nutrients.
The pelletization stage is the most important stage in the animal feed mill, since the feed powder is converted into pellets of the desired size and shape. Compared to the flat die feed pellet machine, the ring die feed pellet machine has a larger capacity. See more information about our animal feed mill equipment for sale >>
The feed pellets are produced at a temperature of 88 degree centigrade and have a moisture level of 17-18%. For cooling, drying and storage, the moisture level should be reduced to 10-12% . Hence the feed pellets are passed through the pellet cooler, where they are cooled to a temperature which is close to room temperature, dried to reduce the moisture levels.
After the animal feed pellets are produced, a semi automatic packing machine is used to put the pellet feed in bags so that they can be stored or transported to the end customer. A computerized machine will measure the feed of a specific amount for each bag, and it will be pneumatically discharged to the bag for packing. The bag with the pellets will move on a conveyor to the area where machines will automatically stitch the open tops of the bag, so that they can be transported.
Many farmers are keeping poultry, like duck, chicken, broiler, hen, goose, pigeon, etc. for their meat, eggs, and other products, and they have to feed them regularly with pellet feed, since it is available throughout the year. Hence there is a lot of demand for feed manufacturing machines which can be used for converting raw material into mash feed or pelleted animal feed. Some of the raw materials which are used for the feed mill are maize, grain, MBM, straw, grass, alfafa, molasses, it depends on the availability of the material. The capacity of the feed mill should be selected based on the demand for the material. (You maybe also interested in: how to make chicken feed? )
What's The Cost To Start an Animal Feed Production Business Plan? If you are about to start poultry or cattle feed business in India or other countries. Most farmers or businessmen would like to know how much money is needed to invest in the first place. In fact, the cost of setting up livestock feed mills is closed related to various factors including feed formulation, production output, feed production process design, feed milling machine selection and factory layout. Here we can give some references list for you: (Read more about setting up animal feed manufacturing company in Inda>>)
Note: When it comes to project investment cost, you need to consider raw materials, workshop rent, equipment cost, project installation and commissioning charges, production cost, labor cost and so on.
Easy Operation: The animal feed manufacturing company only requires a couple of workers to operate it. Adult people who have the basic feed processing knowledge can operate it very well after training. So, it also helps to reduce the running cost of your company.
Low Investment Cost: Its compact size takes up less space and the installation and commissioning is relatively easy. Therefore, except the investment for the equipment itself. The extra cost for the pellet production line is really small. (Related article: pig feed making machine price>>)
The animal feed manufacturing process design and equipment provided by ABC Machinery has many advantages that attract customers from Mexico, America, Italy, India, Nigeria, Ghana, South Africa and more countries. Any questions about the animal feed manufacturing process, please contact us freely!
Textile fibres have certainly provided an essential element in contemporary society and physical formation pointing out human comfort. Human is a companion of fashion. Textile Manufacturing process is beginning towards the production of any garment or Textile Products. The aspirations for quality garment and apparel gave rise to development of textile fibres and textile production units. The textile companies meet the requirements of human in terms of attire and this attire is brought into the market after a specific procedure. Textile manufacturing is an extensive and immense industry having a complex procedure. It undergoes range of stages as converting fibre into yarn, yarn into fabric and so on ending up with clothing as a concluding product.
Currently, textile production units include significant quality of textile process for manufacturing that adds value in fiber. The cloth production is not an output of few stages but it do undergoes from various steps. The process describing the stages of manufacturing procedure is listed below:
Spinning is a procedure of producing/converting fiber materials in yarns. On an initial stage it goes through the blowroom where the size of cotton becomes smaller by the help of machinery followed by carding. After carding, the process is continued by drawing which includes attenuating in spinning mills. The silver produced by drawing is then processed for combining where consistent size of cloth is attained. It is then stepped further for roving for purpose to prepare input package. This roving is attenuated by rollers and thenspun around the rotatingspindle.
Weaving is second level after spinning. Here, the yarn from spinning section is sent further for doubling and twisting. It is than processed for shifting of yarn in convenient form of package containing sufficient yarn length. At the stage of creeling the exhausted packages are replaced with the new ones which is followed by wraping. The wrap yarn is provided a protective coating to lessen the breakage of yarn which is called as sizing. It is considered as an important segment. This yarn is then processed for winding on weavers beam supported by the final step of weaving.
Dyeing as well as printing of fabrics are usually carried before the application of other finishes to the product in dyeing mills. It provides colour to fabric and also improves the appearance of it. The product is then converted from woven to knitted cloth known as finishing. Finishing is specifically carried after dyeing or printing to give a specific look.
Garment manufacturing is the end procedure converting semi-finished cloth into finished cloth. There are various steps completed by garment manufacturing companies for the production of cloth. These processes include- Designing, Sampling, Costing, Maker Making Cutting,Sewing Washing, Finishing, Packing, Final Inspection, Dispatch and much more.
The above description could provide you a brief idea about the textile process in industries. Apparel/cloth is not an outcome generated in simple steps instead it includes lengthy mechanical procedures. Decades ago, the traditional method of producing cloth was used which is now been replaced by automated textile machinery in specific mills like spinning mills, Ginning Mills, Dyeing Mills, Processing Units and more.
I have in earlier posts covered rubber machinery like Bale Cutter, Mixer, Mixing Mill, Batch-Off, Extruder, Tire Buffer, etc. However, its intriguing to see where all these equipment (alongwith the other machinery)goes into tire production.
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Categories: Allied Machinery, Calendering Machinery, Compounding Machinery, Curing Machinery, Cutting Machinery, Extrusion Machinery, Lab Equipment, Mixing Machinery, Moulding Machinery, Tire Industry, Tyre Building Machinery, Vulcanizing Machinery | Tags: Rubber Machinery, Tire Production, Tube Production | Permalink.
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Rubber ball wash is nothing but a garment and softener wash. In this process, garments will be softer and at the same time abrasion will come. When we need more hand feel of garments at that time we will use this process. Rubber will be added in the same bath of softener or in the dryer with the garments. Process Flow Chart of Rubber Ball Wash is as follows:
We are living in the fashionable era. Everyone wants to wear fashionable clothing. As a result, people can make a difference with others. A basic knitted T-Shirt and a washed knitted T-Shirt are totally different in to look. At present, the knitted washed item is a hot-cake for the young generation.
In that case, Rubberball wash is such a solution for garment and softener wash. In this process, garments will be softer and at the same time seam abrasion will come. We use this wash to get more hand feel of garments. Rubber balls are added in the same bath of softener or in the dryer with the garments.
Rubber, elastic substance obtained from the exudations of certain tropical plants (natural rubber) or derived from petroleum and natural gas (synthetic rubber). Because of its elasticity, resilience, and toughness, rubber is the basic constituent of the tires used in automotive vehicles, aircraft, and bicycles. More than half of all rubber produced goes into automobile tires; the rest goes into mechanical parts such as mountings, gaskets, belts, and hoses, as well as consumer products such as shoes, clothing, furniture, and toys.
The main chemical constituents of rubber are elastomers, or elastic polymers, large chainlike molecules that can be stretched to great lengths and yet recover their original shape. The first common elastomer was polyisoprene, from which natural rubber is made. Formed in a living organism, natural rubber consists of solids suspended in a milky fluid, called latex, that circulates in the inner portions of the bark of many tropical and subtropical trees and shrubs, but predominantly Hevea brasiliensis, a tall softwood tree originating in Brazil. Natural rubber was first scientifically described by Charles-Marie de La Condamine and Franois Fresneau of France following an expedition to South America in 1735. The English chemist Joseph Priestley gave it the name rubber in 1770 when he found it could be used to rub out pencil marks. Its major commercial success came only after the vulcanization process was invented by Charles Goodyear in 1839.
Natural rubber continues to hold an important place in the market today; its resistance to heat buildup makes it valuable for tires used on racing cars, trucks, buses, and airplanes. Nevertheless, it constitutes less than half of the rubber produced commercially; the rest is rubber produced synthetically by means of chemical processes that were partly known in the 19th century but were not applied commercially until the second half of the 20th century, after World War II. Among the most important synthetic rubbers are butadiene rubber, styrene-butadiene rubber, neoprene, the polysulfide rubbers (thiokols), butyl rubber, and the silicones. Synthetic rubbers, like natural rubbers, can be toughened by vulcanization and improved and modified for special purposes by reinforcement with other materials.
Commercially, natural rubber is obtained almost exclusively from Hevea brasiliensis, a tree indigenous to South America, where it grows wild to a height of 34 metres (120 feet). Cultivated in plantations, however, the tree grows only to about 24 metres (80 feet) because carbon, necessary for growth, is also an essential constituent of rubber. Since only atmospheric carbon dioxide can supply carbon to the plant, the element has to be rationed between the two needs when the tree is in active production. Also, with foliage limited to the top of the tree (to facilitate tapping), the intake of carbon dioxide is less than in a wild tree. Other trees, shrubs, and herbaceous plants produce rubber, but, because none of them compares for efficiency with Hevea brasiliensis, industry botanists have concentrated their efforts exclusively on this species.
In the cultivation of Hevea, the natural contours of the land are followed, and the trees are protected from wind. Cover crops planted adjacent to the rubber trees hold rainwater on sloping ground and help to fertilize the soil by fixing atmospheric nitrogen. Standard horticultural techniques, such as nursery growing of hardy rootstocks and grafting on top of them, hand pollination, and vegetative propagation (cloning) to produce a genetically uniform product, are also employed.
Hevea grows only within a well-defined area of the tropics and subtropics where frost is never encountered. Heavy annual rainfall of about 2,500 mm (100 inches) is essential, with emphasis on a wet spring. As a consequence of these requirements, growing areas are limited. Southeast Asia is particularly well situated for rubber culture; so too are parts of South Asia and West Africa. Cultivation of Hevea in Brazil, its native habitat, was virtually destroyed by blight early in the 20th century.