powder grinding mill mining

cgs fluidized bed jet mill - netzsch grinding & dispersing

The new e-Jet System (efficiency, economy, ecology) Where air jet mills not economical for your product and application in the past? Not anymore! We have closely examined the energy efficiency of this technology. The result is a completely new grinding method. Until now air jet milling, due to its energy consumption, was only cost efficient when applied to high value products. Now many other materials can be economically processed in our fluidized bed jet mills. Economy is only one of the distinguishing features of our new e-Jet System (patent pending). Process optimization through the adaptation of grinding conditions provides energy savings of up to 30 % compared to the conventional operation of air jet mills. Products that in the past could only be economically processed in mechanical mills, can now be micronized even more economically in our CGS Fluidized Bed Jet Mill using the e-Jet System. Convince yourself! This energy efficient milling system is now available for direct comparison in our laboratory in Hanau!

Size Reduction of Talc: In most cases industrial mineral manufacturers do not consider jet mills to be an economical alternative for material processing. However, talc is one exception, with high added value and a growing market. The specifications are also getting more strict leading to the advantage of a higher technology process.

Typical toner products have a D50 in the range of 5 m 7 m. NETZSCH Trockenmahltechnik GmbH entered the field of toner processing with the development of the CGS Jet Mill in the 1990s followed by the CFS/HD-S High Dispersion Air Classifier a few years later.

NETZSCH Trockenmahltechnik GmbH, one of the global leading companies in the area of dry product processing, is part of the Business Unit Grinding & Dispersing of the NETZSCH Group. Customers profit from our comprehensive experience potential and our diverse machine program, ranging from laboratory- and production machines to complete production lines. Fine impact mills, classifying- and jet mills as well as fine-cutting mills and high-efficiency fine classifiers made by NETZSCH are mainly used in the application areas chemistry, inorganic materials/minerals, ceramics and life science for pharma- and food applications.

In the ceramic industry the mechanical treatment of raw materials, processed or finished powders is an important part of many production processes. At the same time the grinding- and classifying processes are also of primordial importance, in order to ensure a range of particle sizes which is usually exactly defined for the particular process. The grinding principle of jet milling has proved itself to be particularly effective for the grinding of ceramic and abrasive materials. They can be ground to high finenesses, with an exact upper particle size limit, in one working step.

Sofraced, the only company in France to manufacture ceramic powders for use in dental prostheses, has decided to diversify its grinding processes. At first glance, this seems simple, but the new process requires a ceramic powder devoid of all traces of other materials, in order to prevent alterations in its color and bio-compatibility. Ceramic is highly abrasive. NETZSCH Trockenmahltechnik GmbH, builder of grinding machines and equipment was asked to assist in finding some good solutions. This was not always easy!

In addition to its well-known blackening ability, the other notable characteristics of graphite are its high temperature and oxidation stability, its resistance to chemical acids, its excellent lubricity as well as its electrical conductibility. Aside from"natural graphite", a particularly typical kind mined from deposits, which is processed after extraction, graphite can also be produced synthetically. The "natural process" is carried out within several days or weeks in resistance furnaces using carbon carriers, such as petroleum coal.

Mechanical treatment of raw, consumable or prefabricated materials is an important part of many methods of production in the chemical industry. Numerous steps of a wide variety of production methods are necessary to obtain the desired finished material. The fluidized-bed jet mill enables organic pigments to be processed to a high fineness with a maximum particle size.

Air classifiers are used for the classifying of dry bulk products. They are either used on their own, independently, or as an integral part of a mill. Up until now a large amount of complicated equipment was required in order to obtain finest cut points even at high capacities. This is why up to 8 classifier wheels were used. However, there are alternatives.

The interest in finer, dry products has led to the development of more efficient jet milling processes. The first part of the paper describes the thermodynamic basic principles for generation and application of steam, and compressed gases. Practical experience has shown that in the aspired fineness range stabilization during grinding provides an enormous potential for improvement. Some selected examples demonstrate that the energy requirement can be reduced by a factor of more than two by suitable choice of stabilizers.

The s-Jet System (patent pending) is a new innovation in a line of consistent developments being made in the area of air jet milling. Final finenesses in the submicron range (example: d50 0.2 m) can now be achieved with fluidized bed jet mills. As opposed to conventional dry grinding processes with fluidized bed jet mills, the s-Jet System uses superheated steam as its milling gas.

The ConJet high-density bed jet mill is a spiral jet mill combined with a patented dynamic air classifier. This classifier enables the ConJet to achieve highest finenesses independent of the product load, and therefore also highest throughput rates. Applicable for finenesses from 2.5 to 70 m (d97).

This newest fine classifier was conceived to combine with an upstream mill. The direct integration of the InlineStar classifier behind a mill creates a continuous grinding/classifying plant that reduces the number of required plant components.

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chemical industry - netzsch grinding & dispersing

NETZSCH continually responds to the demands of the chemicals industry and makes a significant contribution to the cutting-edge production of high-quality paints, coatings, printing inks, high-performance ceramics, adhesives, sealants, pesticides and batteries.

Decisive factors for global success include the extensive product range, the pilot-plant and production-scale machines and the complete production facilities. NETZSCH stands for efficient processes, maximum production capacity and reproducible product quality, as well as modern, user-friendly and innovative machine design.

From our various technology centers in Europe, Asia and North and South America, we support our customers in all phases of investment and production with our know-how and numerous services The Business Field Chemicals unites the most advanced production plants and technology leadership and guarantees outstanding performance for customer-oriented process solutions

We use cookies in order to design our websites optimally for you. Some of them are technically necessary, while others help us to improve this website and your experience. You are free to decide which categories you would like to permit. Please note that depending on the settings you choose, the full functionality of the website may no longer be available. Further information can be found under Cookie Details.

These cookies are essential in order to enable you to move around the website and use its features, such as setting your privacy preferences, logging in or filling in forms. Without these cookies, services requested through usage of our website cannot be properly provided.

In order to continuously improve our website, we anonymously track data for statistical and analytical purposes. These cookies collect information about how visitors use a website, for instance which pages visitors go to most often, and how visitors move around the site. They help us to improve the user friendliness of a website and therefore enhance the users experience.

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Shanghai Clirik Machinery Co., Ltd located in PUDONG New district of Shanghai china as a professional enterprise, which is specializing in research, manufacture and sales of all kinds of mining equipment.

Our company has already formed a full set of modern production line, equipped with intelligent, standardized testing and controlling laboratories, owned a professional team for R&D, production, sales and service.

So far, we have established a whole production chain, the products covermicro powder grinding mill, high pressure grinding mill, Europe an version coarsegrinding mill, hammer crusher, jaw crusher, screw conveyor, bucket elevator and so on. They are widely used in the industry of mining, construction materials, chemicals, metallurgy, transportation, hydraulic engineering and so on.

Specially we independently developed HGM micro powder grinding mill, which are not only renowned in domestic market, but also have been sold widely in Eastern Europe, Middle East, Africa, South Asia, Southeast Asia, Oceania, and America, etc.

Shanghai Clirik Machinery Co., Ltd is a large professional manufacturer with import & export rights specializing in research, manufacture and sales of crushing machinery, mining equipment, and grinding machines, such as micro powder grinding mills, ultrafine mills, vertical roller mills etc.

types of underground mining method comparison

In any discussion of Methods ofUndergroundMining Comparison, one is repeatedly confronted with the difficulty of dealing with so many variable conditions. It is not an exact science and in the choice of a method each varying factor has a certain weight, which, in many cases, experience alone can determine. In mathematical terms, it is a function of many variables.

A discussion of Underground Mining also loses much of its value unless costs are considered, because the expectation of profit is the only excuse for carrying on mining at all. As conditions vary they cause fluctuations in cost and there are few operations to which a definite cost can be assigned. The character of the ore may make it difficult to drill, yet because of the ease with which it breaks the total cost of drilling and blasting may be low.

In preparing this article the attempt has been, not to cover the whole field of mining, but to describe the different methods of stoping and mining which have distinct principles. In addition to this an effort has been made to show the advantage of dissecting the methods into their detailed operations and applying to these a mathematical study as an aid to the judgment in determining which is the best method to adopt, or in attempting to reduce the cost of a method already in use.

Methods of mining include stoping, caving, and various methods of working large deposits which, in addition to the method of actually breaking the ore, require elaborate and definite plans of, development of the orebody. The ordinary methods of stoping are too familiar to all for any elaborate discussion, but it has seemed advisable to review the subject and give the principal advantages and disadvantages of the different methods.

The size and shape of the deposit: Character of the ore, whether high or low in grade. Whether the values are regularly or irregularly distributed. Physical character, whether hard or soft, tough or brittle. Character of the country rock. Immediate and future demands for ore. Amount of development work done or that may be necessary. Amount of water to be handled. Cost of power, timber, and supplies. Ventilation. Whether drilling is to be done by hand or with machine drills.

The method of underhand stoping in which the ore is drawn to the level above (B, Fig. .1), is called Cornish stoping. It finds application only when it is necessary to mine a lens of good ore below a level and it is not practicable or financially possible to do the necessary development to come up from underneath. Its disadvantages are the excessive cost of raising both ore and water.

Underhand stoping where the ore is drawn from the bottom (A, Fig. 1), has more merit than is usually accorded it, especially in the Western States. On the Rand it has been used almost exclusively. Its advantages and disadvantages as compared chiefly to overhand stoping are as follows:

uppers in a shift. South Africa had its native labor which could not be taught to drill them. It might seem on first thought that the disadvantages are so numerous that they preclude any chance of the method being adopted under ordinary labor conditions, but I have examined mines where the combination of conditions in narrow veins indicates very strongly that the method would be more economical than overhand stoping and quite as safe.

Starting an Overhand Slope.In Fig. 2 are shown various methods of working the back in overhand stoping. To start the stope, if the ore is low grade and timber is scarce, a pillar or pillars are left above the level as shown in A, and if the ore is high grade it is all removed above the level and stulls are placed as shown at B. To start a stope as shown at B, a cutting out or lead stope is broken immediately above the level as shown at D, Fig. 2. C, Fig. 2, is a wide raise or raise stope, which is one method of opening an overhand stope, and E is a drift stope, which is a term used in the Lake Superior copper mines and means a wide and high drift as a start for the overhand stoping.

After starting an overhand stope the shape in which the back is carried is often of prime importance. In A, Fig. 2, is illustrated the method of carrying a flat or longitudinal back (the term long-wall is used sometimes when the vein lies nearly flat). In this method the benches or breasts are frequently made of a height sufficient to allow of a square set being placed. This is done at Butte and it is often referred to as breast stoping. In general, a flat-back stope as illustrated has the following advantages and disadvantages:

Shrinkage stoping refers to any overhand method in which the stope is kept full of broken ore until it is completed. The miners stand on top of the broken ore and work at the back. As broken ore takes up more space than ore in a solid mass, about 35 to 40 per cent, of it must be drawn to leave room for working.

Although shrinkage stoping is rather generally used, it would be used more if it were not for the fact that many mines are hot in a condition to keep an ore reserve, but must draw the ore for the mill as fast as it is broken. The added efficiency to be obtained from the miners when working on a firm floor of ore, and not on loose lagging laid on stulls, is a very important advantage of the method.

In a discussion of stoping methods, steeply pitching veins are usually referred to, because the majority of veins in nature are steeper than 45, and also because to refer each method of stoping to veins of all dips causes confusion. Before considering combination stoping, however, a brief resume of the methods of handling ore in veins of different dips is necessary. In veins dipping from 35 or 40 up to 90 the ore runs down by gravity. From 20 to 35 it must be assisted by shoveling, or by using chutes with smooth bottoms or placed at an angle steeper than, that of the vein. From 10 to 25 the ore may be taken down to the level by shoveling, shaking chutes, mono-rail trams, gig-back railways, or conveyors. From veins that are horizontal up to those having dips of 10 to 15 tracks are usually laid on the foot wall and cars are pulled up to the face by men or animals. An animal can pull an empty car up a 6 slope and a loaded car up a 3 slope. So in dips greater than 6 the track must be laid at an angle with the line of the dip.

In combination stoping, which is illustrated in Fig. 3, and which is a combination of underhand and overhand stoping, it is possible to keep the working face more nearly in a line parallel to the raises and perpendicular to the level. This is a distinct advantage if a stationary or shaking chute is being used to carry the ore to the level, because a large part of the face of the stope is accessible to the chute. This becomes a double advantage if a large output is required. In combination stoping development work is also reduced because levels may be driven far apart, and fewer raises are required than in simple underhand stoping.

Breast stoping refers to the working of a flat orebody, or a flat section of an orebody, just as coal is mined from a flat coal seam. That is, a slice is worked in a horizontal direction. The assumption is that there is no open stope either above or below the slice, or else the method

becomes either underhand or overhand stoping. In some cases the benches in underhand or overhand stoping are called breasts, and the method breast stoping, but I believe that is not the usually accepted definition. Breast stoping, in the strict sense, is the only name applicable to the mining of a horizontal slice, such as the sill floor of a large overhand stope, or the slices in the top-slicing method.

This method, described by F. W. Sperr in the Engineering and Minting Journal of June 5, 1912, and by P. B. McDonald in the Mining and Scientific Press of July 5, 1913, is really a combination of several different methods of stoping. Fig. 4 is an illustration of the method, and shows half of the vein cut away where the stoping is being done. The miners go from the haulage level up the raise into the sublevels. On the first sublevel they will blast into the shape of funnels the raises that come up from the haulage level, and after working back, the slice, s, by breast stoping will drill holes at a and shoot part of this bench down into the raises. On the second sublevel the miners work back the slice, s, and then with down holes at b will blast the remainder of the first bench down into the raises, and with uppers at c shoot off part of the second bench. Both sets of holes will be fired at the same time. In this way

each sublevel is drawn back; the broken ore is drawn off through the funnel-shaped raises, which leaves a large open stope. The sublevels are driven about 25 ft. apart vertically, and 8 to 10 ft. are shot off from each bench from the sublevel below. Obviously where there is a capping above the ore, as shown in the cut, part of it will fall when the upper bench is blasted and part or all of this ore may be lost. When the ore is from 50 to 100 ft. wide, a narrow stope of about one-third of the width of the ore is drawn back through the middle, leaving a pillar of ore standing on each side. These pillars or slabs left against the walls are then drawn back in the same manner. The method is applicable to veins from 12 to 100 ft. wide, or wider, if pillars are left between stopes, and evidently comes into competition with shrinkage stoping, square-set stoping, and top slicing. It requires expensive development but permits a large tonnage to be broken in a relatively small stope. The working back of the slices on the sublevel is expensive mining, but after that is done the rest of the ore blasted from the benches requires a comparatively small amount of powder.

Square-set stoping may refer to any method of stoping in which square-set timbers are used. Unless otherwise specified, however, the term is limited to overhand flat-back stopes in which square sets are used, either with or without waste filling. Square-set mining is advantageous when the vein is wide and the walls will not stand without timbering and shrinkage stoping cannot be used; when, on account of surface conditions, caving cannot be allowed, or where caving might cause the loss of other orebodies; when the ore changes rapidly in grade and requires frequent sampling; when the orebody is irregular in outline; and when old stopes may have to be approached or passed through at some later time.

Mine workings are filled with waste as an aid to timbers in supporting weak walls or back, or to avoid fully or in part the use of timbers. Workings that must be prevented from caving for a length of time in the future are best protected by waste filling. The filling may be waste rock from development, rock blasted from the walls or surface for the express purpose of filling, or, if available, sands, from concentration mills make excellent filling and are cheaply placed in the stopes.

There are three distinctive methods of working large deposits that involve, in some way, the factor of caving. Slightly different names are in use, but those that are simple as well as descriptive are top slicing, sublevel caving, and block caving. In a discussion of these methods, three things must be borne in mind: that the methods are usually applied to massive deposits; that the deposits are usually divided into blocks or panels, and the description of mining one panel is practically a complete description of the method; and that, in most cases, the orebodies do not come to the surface but are covered with a capping. This capping may be glacial drift, as in some instances in the iron regions around Lake Superior, or it may be rock from which the ore values have been leached, as is the case at some of the large copper deposits.

Top slicing, illustrated in its ideal form in Fig. 5, consists in the working of an orebody in horizontal slices, beginning at the top. Levels, for haulage, are established at proper intervals and, from these, raises are put up to the top of the orebody about every 50 ft. Starting at the tops of these raises drifts are run out and then, retreating toward the raise, the slice is worked back by breast stoping. The overburden or

capping lying above the ore is supported on square sets or posts until a slice, or part of a slice, has been worked. The floor of the slice is then covered with slabs or plank and the supporting timbers are shot out and the capping is allowed to cave on to the timber floor. This floor and the broken posts form what is called a mat, which keeps ore and capping separated. The miners then start in the raise and work out another slice of the ore just under the previous one and catch up the timber mat with posts or square sets. When this slice is completed another floor is laid and the supports again blasted. In this manner the ore-body is worked in successive slices from the top downward. The broken ore from each slice is run to the raise in wheelbarrows or cars and dropped to the haulage level. The capping caves and follows down on top of the mat.

In this method the ore is not caved at all, but the ground above the ore does cave, and the surrounding country will cave more or less according to the amount of ore removed. If there are any other orebodies in the region affected by the cave, they will be lost or their recovery made more difficult. This is one of the reasons which may prohibit the use of caving methods. Also, unless the deposit is small compared to the distance to the surface, surface subsidence will take place and the surface must be free from buildings or roads. Top slicing is adaptable to heavy ores that can be mined easily, and require heavy timbering and filling if worked by overhand stoping. Deposits of large extent, over which the overburden will cave readily, are customary conditions. In some cases, top slicing may require as much or even more timber than an overhand stope with square sets, but for very heavy ore, which if worked overhand necessitates strong sets, reinforced and braced, it takes less timber, and in any case poorer timber may be used.

It is possible to work only on the top of the ore, and although several slices may be worked at the same time, it is not possible to establish work at different levels. This may make it difficult to obtain a required tonnage from a deposit of small horizontal section. Capping should cave readily, and not arch, or the method may become very dangerous.

This method, otherwise referred to as sublevel drifts and back, caving, or sublevel slicing, resembles top slicing in that the orebody is worked from the top down, and the ore is taken out in horizontal slices. A block

of ore is left above the slice, however, and when a small portion of the slice has been mined out, this back is allowed to cave. Fig. 6 shows a block or panel of ore worked by sublevel caving. Raises are put up from the haulage level, and from these sublevel drifts are driven 14 to 20 ft. apart vertically. When these drifts reach the boundary of the property, or of the panel to be worked, cross drifts as a, b, and c are driven across the block and timbered. The back of ore is thus undercut but is supported by the drift timbers. The timbers of cross drift a are next blasted and the weight of the capping caves the back of ore down on to the floor of the slice, where the miners shovel it into cars and push it to the raise. A timber mat may be used as in top slicing. Sublevel caving is adaptable to massive deposits or wide veins in which the ore is not difficult to break, yet is firm enough to hold the capping while supported by the drift timbers. An overburden that will readily cave is necessary.

Block caving is an extreme case of sublevel caving in which instead of a back of ore 5 to 10 ft. thick, one 50 ft. thick is undermined and allowed to cave. The method is illustrated in Fig. 7. After the bottom of the block, or panel, is cut up into pillars by drifts and cross drifts, the pillars are robbed, and then the remaining stumps are blasted out with one large blast. This allows the entire block above to cave. In settling it disintegrates so that it can be shoveled with very little additional blasting. For a block to cave it is usually necessary for it to be freed on one or more sides. This is done, as shown in the cut, by narrow stopes, called isolating stopes. After the ore has settled for from two to six months timbered drifts are driven through it. The broken ore is allowed to run into these drifts, starting farthest from the shaft, is shoveled into cars and trammed out. As soon as capping shows at any point shoveling is stopped.

There is another principle that should be mentioned under mining methods. It is called back caving into chutes or chute caving and in some ways resembles block caving. (The description of a mine employing this principle is given in Mining Without Timber, by Brinsmade, p. 181.) Large overhand stopes are worked, not by drilling and blasting the entire back, but by blasting out narrow isolating stopes around the edges of the

main stopes and allowing the rest of the ore in the center to fall of its own weight. That is, a large percentage of the ore is mined by caving. The broken ore is drawn off through chute raises in the bottom of the stope.

As far as I am aware, the preceding pages cover every method of mining that has a distinctive feature and can be readily classified. There are innumerable different systems of mining but they all involve only these principles, or modifications and combinations of them.

university of illinois opens feed technology center

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The University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES) recently held a digital event to mark the grand opening of the Feed Technology Center at its campus in Urbana, IL following two years of construction, the university announced this week.The $20 million, 12,000-sq-ft facility contains an array of new equipment, automation technologies, and safety and sanitation features.

The Feed Technology Center is a game-changing asset that elevates our ability to live into our land-grant mission, said Kim Kidwell, den of the College of ACES, in a release. This facility not only expands our ability to conduct innovative research and train the next generation of leaders in animal nutrition, it gives us a new avenue to reach out to industry stakeholders and provide continuing education opportunities.

U of Is Urbana site features 195,000 bu whole dry grain storage with three 65,000 bu bins, a 10,000 bu wet grain bin, 12 concrete truck loadout bins, a dryer with a capacity of 750-1000 bu/hr, and an automated control system for food production. The facilitys mill production rate is about 20 tn/hr of mash feed and 5 tn/hr of pelleted feed.

The Feed Technology Center also contains a number of assets for ingredient processing, including grinding, pre-mixing, mixing, pelleting, crumbling, bagging, a standalone extrusion line, and delivery of research animal diets. To assess quality of feed, the site will use a multi-channel, inline near infrared (NIR) system to monitor the composition of ingredients in real time.

The companies, organizations, and individuals supporting the project partnered with us to continue the universitys preeminence in animal nutrition and feed manufacturing. This facility an ongoing partnerships will move the entire industry forward, Kimberly Meenen, assistant dean for advancement in the College of ACES, said in a statement.

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In recently year, because of the energy-saving advantage in cement industry by vertical roller mill, the comprehensive benefit become more and more obvious, widely application and popularize in power, metallurgy, chemical industry and nonmetal etc.

Vertical roller mill is mainly used for grinding raw meal, clinker, Ground Granulated Blast Furnace Slag, iron ore, limestone, coal powder, coke powder, coal gangue, fly ash, volcanic ash, gypsum, calcite, pyrophyllite, quartz, clay, sandstone, bauxite and other processing industry related to metal and non-metal mine.

1Powerconsumptionslag25kWh/tcement18kWh/trawmeal9kWh/t 2Moisturecontentslag15%cement3%rawmeal7% 3Ffinishedproductfinenessspecificsurfaceareaofslag4200~112500px/gspecificsurfaceareaofcement3300~380cm/grawmealfineness-80mR12~15% 4Moisturecontentofrefinedpowderslag0.5~1.0%cement0.5~1.0%rawmeal0.5~1.0% 5Thespecificinstalledcapacityandparameterscanbeadjustedproperlyaccordingtoactualmaterialnature. 6Theaboveparametersareapplicableforgranularblastfurnaceslag,cementandrawmealandthemodelselectionisdeterminedbymaterialproperty.