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ceramic ball mill types

ceramic ball mill for grinding materials - ftm machinery

ceramic ball mill for grinding materials - ftm machinery

What kind of materials that the ceramic ball mills can process are always the focus of the miners. Can they show the safety and high efficiency? Does it really meet the demands or special demands of customers?

The ceramic ball mill is a small ball mill mainly used for mixing and grinding material. In ball mill ceramic industry, it has two kinds of grinding ceramic ball mill, one is dry grinding ceramic ball mill, and another is wet grinding ceramic ball mill.

Ceramic ball mill is mainly used in material mixing, grinding. Henan Fote Heavy Machinery Co., Ltd has two kinds of grinding ceramic ball mill, one is dry grinding ceramic ball mill, and another is wet grinding ceramic ball mill. The machine can use different liner types according to different production needs. The fineness of the grinding is controlled by grinding time.

The ceramic ball mill machinery has the advantages of less investment, lower energy consumption, novel structure, easy operation, stable and reliable performance and so on, which is suitable for grinding common and special materials. Customers can choose suitable types of ceramic ball mill jars according to the specific gravity, hardness, and capacity of materials.

It also named the ceramics ball mill, is a small ball mill mainly used for material mixing and grinding considering its products having features of regular granularity and power saving. China Fotes ceramic ball mill can do both dry and wet grinding and can choose different lining boards to meet various demands according to different production requirements.

The grinding ceramic ball mill uses different ball mill ceramic liner types according to production needs to meet different needs. The finess of ceramic ball mills depend on the grinding time. The electro-hydraulic machine is auto-coupled and decompressed to reduce the starting current. Its structure is divided into integral and independent.

The grinding fineness depends on the milling time. The motor of the ceramic ball mill is started by the coupling reduce voltage which lowers the starting electricity and the ball mills structure is divided into integral type and freestanding type; advantages of the ceramic ball mill are lower investment, energy saving, structure novelty, simply operated, used safely, ability even, etc.The ceramic ball mill is suitable for mixing and milling of the general and special material. Users could choose the proper type and line, media material depending on material ratio, rigidity, and output size, etc.

Ceramic ball mill is the typical grinding equipment which us ball mill ceramics, greatly improves the grinding fineness. Compared with the traditional ball mill, such kind of ball mill has a great advantage in function, structure, and operation. This machine also has great capacity, high technology, and no noise, which plays an important role in the field of Metallurgy, building materials, chemicals, industry.

The small tonnage glaze ball mill is the main machine used to make glaze ceramic grinding balls by the industries of producing household porcelain, electrical porcelain and building porcelain. It is applied to grind different glaze materials with different colors and has features of good grinding quality, compact structure, little noise, and simple maintenance.

The ceramic ball mill is a wet type grinding machine for the ceramic materials which can realize high efficiency for fine grinding of the medium crushed materials. Then, how to ball mill ceramic powder? Once users add raw materials, water, and ceramic grinding media in a proper proportion into the cylinder of the ball mill, they will get the ideal product particles by adjusting the required grinding period.

The fine material slurry is especially suitable to be applied in the industries of large-sized household porcelain, electrical porcelain, building porcelain and chemical engineering. And thats the main reason why the producers love ceramic glaze ball mill so much.According to the different demands, the ceramic grinding ball millcan produce different range of the partical ship.

This is a 3-foot by 6-foot continuous ball mill, and this machine will process one ton an hour at 65 mesh. You can actually process finer than that, down to about 200 mesh, but the throughput goes down. To the feed side, you can put three quarter to one inch minus here. then, ore enters into the scoop of ball mill, with a two-ton charge of balls. The material works its way through the ball mill, which turns about 35 RPM, with the water addition. To the discharge, they will go on to the shaker tables for concentration.

Here are three different size balls we use. And you add equal amounts of each size ball when you charge the mill. And then as the balls wear, you keep putting in larger balls. Again, it is about a two ton charge of balls. The machine empty weighs about 8,500 pounds, with the charge of balls, it weights about 12,500 pounds.

lets look inside the ball mill now, you can see it has cast armor lining the inside of mill. This is the feed side, and across the mill, here is the discharge side, and it has a grate to keep the balls in. There is an augur in there that screws the material back in, so only the finest material can exit the mill.

The mill weighs a little more than 3 tons, and you can easily turn the mill with one hand. So, its a really smooth mill, not a lot of friction. It runs with a 25 horse, 3-phase motor. And here in a couple weeks, well be getting this mill up and running and put a lot of balls in and run some material.

First. Installing the main bearing. In order to avoid the aggravating the wear of shoulder and bearing lining of the hollow journal, the gap between the base plate of two main ceramic ball mill bearings is no more than 0.25mm.

Second. Install the barrel of ceramic ball mill. According to the specific conditions, the pre-assembled whole simplified parts can be directly installed or installed in several parts. Check and adjust the center line of the journal and ceramic ball mill.

Third. Install transmission parts such as pinion gears, couplings, reducers, motors, etc. In the process of installation, measurements and adjustments should be made according to product technical standards. Check the radial slip off the ring gear and the meshing performance of the pinion, concentricity of reducer and pinion, and the concentricity of motor and reducer. Until all installations are ready, the foundation bolts and the main bearing bottom plate can be watered.

3 types of grinding media for ball mills - ftm machinery

3 types of grinding media for ball mills - ftm machinery

Grinding media, used to extract the concentrate for the production of metals, are the main components in the ball mill grinding process. There are different types of milling media used in grinding such as steel balls, ceramic balls and cylpebs.

Steel grinding media are ideal for extracting precious metals in ore beneficiation. Spherical ball mill media have an advantage of better crushing effect when impacting large particles because point contact between balls and raw materials makes the materials easy to be smashed.

As the name implies, this grinding media are made of ceramic which is energy-saving and environmentally friendly. The ceramic ball has a Mohs hardness of 9.0, which is second only to diamond, far exceeding the wear resistance of steel and stainless steel. It has the best behavior of wear and its consumption is generally 50% of the steel ball. Under the same conditions, it can extend the service life of the equipment more than 10 times by using ceramic balls.

When the cylpeb is used as the media for grinding, the products of each grain level are relatively uniform. It has certain selectivity for grinding intermediate products and has certain protective effect for minerals, but the crushing strength is not as good as balls. Cylindrical ball mill media is more suitable for fine material grinding because the contact area is larger with the line contacting each other.

(1) If it is too much, the grinding media will be overlapped with each other, thus the crushing capacity of each steel ball cannot be fully utilized and the kinetic energy consumption will be increased.

(2) If it is too little, although the crushing capacity of each steel ball is fully exerted, the total crushing capacity is still limited. Therefore, it is necessary to choose the appropriate amount of ball.

When the speed of the ball mill is fixed and the ball loading is 30% of the total capacity of the cylinder, the balls movement is mainly sliding, but it has begun to pour. When the ball load exceeds 40%, the ball is pouring; When it reaches 50%, the surface of the ball is just on the diameter line of the cylinder, so it is easy to pour which is exactly needed for ball mill production.

According to the actual results, when the charging is 40%, the output is the highest. While it is usually about 35% in real production, that is, the volume of the ball is kept lower than the horizontal centerline.

The ball size in a mill has a significant influence on the mill throughput and power consumption. Here the ball size refers to two aspects, one is the maximum ball size, and the other is the correct ball size ratio.

The size of the grinding media directly affects the grinding efficiency and product fineness. The larger the diameter, the larger the product particle size and the higher the yield. This empirical formula is currently widely used in European and American countries and regions:

However, this problem is difficult to solve because there are too many parameters that affect the size of the grinding ball. At the current cognitive level of human, it is impossible to deduce the theoretical calculation formula of the milling ball diameter. This is because it is impossible to include more than a dozen factors that affect the ball diameter, let alone some influencing factors cannot be described by quantity.

After determining the proper amount of grinding balls, it is also needed to choose the right ball ratio. The most common in production are the two-stage ratio and the multi-stage ratio. Generally, the multi-stage ratio follows the principle of less at both ends, more in the middle which means that large and small balls are less and middle balls are more.

The so-called two-stage ratio is to use two different sizes of steel grinding balls with a large difference in diameter to carry out the grading. The multi-stage is suitable for the materials with small particle size and good abrasive property, while the two-stage ratio is suitable for the materials with large particle size and poor abrasive property.

Steel consumption constitutes a significant proportion of grinding costs in industrial ball mills. Approximately 0.23 billion kg of steel (1986) in the US and over 0.45 billion kg in the world were consumed each year in wet grinding alone. This steel consumption is mainly attributed to the wear of grinding media and liners.

Attrition plays a large part in all fine grinding and has been known and acknowledged. The rate of ball wear during the abrasive process is proportional to the surface area of the ball or the square of the ball diameter.

Electrochemical interactions between the grinding media and minerals, occur especially in wet grinding; resulting in media corrosion. In the same ball mill, the corrosion rate on the surface of each medium will be the same regardless of the size of the mill. Increasing mill size will increase energy consumption, which in turn increases metal loss due to abrasive and impact wear.

The ball to powder ratio is determined by the golden ratio, that is, the ball: material: (water + air) =1.618:1:0.618. The range of ball-to-water ratio mentioned in textbooks is (1.4 ~ 2.2): 1: (0.45 ~ 0.58), without mention of air and the golden section. But in fact, if there is not enough air to scour the water and raw materials, there is no ball grinding efficiency. Its a kind of optimal allocation principle, but the specific will be determined according to the material, the grinding media and the ball mill.

ball mills

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.

grinding mills - common types

grinding mills - common types

In many industries the final product, or the raw material at somestage of the manufacturing process, is in powdered form and in consequence the rapid and cheap preparation of powdered materials is a matter of considerable economic importance.

In some cases the powdered material may be prepared directly; for example by precipitation from solution, a process which is used in the preparation of certain types of pigments and drugs, or by the vacuum drying of a fine spray of the material, a process which is widely adopted for the preparation of milk powder, soluble coffee extracts and similar products. Such processes are, however, of limited applicability and in by far the greatest number of industrial applications the powdered materials are prepared by the reduction, in some form of mill, of the grain size of the material having an initial size larger than that required in the final product. These processes for the reduction of the particle size of a granular material are known as milling or grinding and it appears that these names are used interchangeably, there being no accepted technical differentiation between the two.

Examples of the first two classes occur in mineral dressing, in which size reduction is used to liberate the desired ore from the gangue and also to reduce the ore to a form in which it presents a large surface to the leaching reagents.

Under the third heading may be classed many medicinal and pharmaceutical products, foodstuffs, fertilizers, insecticides, etc., and under the fourth heading falls the size reduction of mineral ores, etc.; these materials often being reduced to particles of moderate size for ease in handling, storing and loading into trucks and into the holds of ships.

The quantity of powder to be subjected to such processes of size reduction varies widely according to the industries involved, for example in the pharmaceutical industries the quantities involved per annum, can be measured in terms of a few tons, or in the case of certain drugs, possibly a few pounds; whereas in the cement industry the quantities involved run into tens of millions of tons; the British cement industry alone having produced, in round figures, 12 million tons of Portland Cement.

For the preparation of small quantities of powder many types of mill are available but, even so, the ball mill is frequently used. For the grinding of the largest quantities of material however, the ball, tube or rod mill is used almost exclusively, since these are the only types of mill which possess throughput capacity of the required magnitude.

The great range of sizes covered by industrial ball mills is well exemplified by Fig. 1.1 and Fig. 1.2. In the first illustration is shown a laboratory batch mill of about 1-litre capacity, whilst in Fig. 1.2 is shown a tube mill used in the cement industry the tube having a diameter of about 8 ft and length of about 45 ft.

In Fig. 1.3 is shown a large ball mill, designed for the dry grinding of limestone, dolomite, quartz, refractory and similar materials; this type of mill being made in a series of sizes having diameters ranging from about 26 in. to 108 in., with the corresponding lengths of drum ranging from about 15 in. to 55 in.

At this point it is perhaps of value to study the nomenclature used in connection with the mills under consideration, but it must be emphasized that the lines of demarcation between the types to which the names are applied are not very definite.

The term ball mill is usually applied to a mill in which the grinding media are bodies of spherical form (balls) and in which the length of the mill is of the same order as the diameter of the mill body; in rough figures the length is, say, one to three times the diameter of the mill.

The tube mill is a mill in which the grinding bodies are spherical but in which the length of the mill body is greater in proportion to the diameter than is the case of the ball mill; in fact the length to diameter ratio is often of the order of ten to one.

The rod mill is a mill in which the grinding bodies are circular rods instead of balls, and, in order to avoid tangling of the rods, the length to diameter ratio of such mills is usually within the range of about 15 to 1 and 5 to 1.

It will be noticed that the differentiation between ball mill and the tube mill arises only from the different length to diameter ratios involved, and not from any difference in fundamental principles. The rod mill, however, differs in principle in that the grinding bodies are rods instead of spheres whilst a pebble mill is a ball mill in which the grinding bodies are of natural stone or of ceramic material.

As the name implies, in the batch mills, Fig. 1.4a, the charge of powder to be ground is loaded into the mill in a batch and, after the grinding process is completed, is removed in a batch. Clearly such a mode of operation can only be applied to mills of small or moderate sizes; say to mills of up to about 7 ft diameter by about 7 ft long.

In the grate discharge mill, Fig. 1.4b, a diaphragm in the form of a grating confines the ball charge to one end of the mill and the space between the diaphragm and the other end of the mill houses a scoop for the removal of the ground material. The raw material is fed in through a hollow trunnion at the entrance end of the mill and during grinding traverses the ball charge; after which it passes through the grating and is picked up and removed by the discharge scoop or is discharged through peripheral ports. In this connection, it is relevant to mention that scoops are sometimes referred to as lifters in the literature. In the present work, the use of the term lifter will be confined to the description of a certain form of mill liner construction, fitted with lifter bars in order to promote the tumbling of the charge, which will be described in a later section.

In the trunnion overflow mill, Fig. 1.4c the raw material is fed in through a hollow trunnion at one end of the milland the ground product overflows at the other end. In this case, therefore, the grating and discharge scoop are eliminated.

A variant of the grate discharge mill is shown in Fig. 1.4d, in which the discharge scoop is eliminated by the provision of peripheral discharge ports, with a suitable dust hood, at the exit end of the mill.

Within the classes of mills enumerated above there are a number of variations; for example there occur in practice mills in which the shell is divided into a number of chambers by means of perforated diaphragms and it is arranged that the mean diameter of the balls in the various chambers shall decrease towards the discharge end of the mill; such an arrangement being shown in Fig. 1.6. The reason for this distribution of ball size is that, for optimum grinding conditions, the ratio of ball diameter to particle diameter should be approximately constant. In consequence smaller balls should be used for the later stages of the grinding process, where the powder is finer, and by the adoption of a number of chambers in each of which the mean ball diameter is suitably chosen an approximation is made towards the desired constancy in the ratio of the ball size to the particle size.

The problem of the optimum distribution of ball size within a mill will be dealt with more fully in a later chapter, but at this point it is relevant to mention a mill in which the segregation of the balls is brought about by an ingenious method; especially as the mill carries a distinctive name, even though no principles which place it outside the classification given previously are involved.

The Hardinge mill, Fig. 1.7, uses spheres as a grinding agent but the body is of cylindro-conical form and usually has a length to diameter ratio intermediate between those associated with the ball mill and the tube mill. The reason for this form of construction is that it is found that, during, the operation of the mill, the largest balls accumulate at the large end of the cone and the smallest balls at the small end; there being a continuous gradation of size along the cone. If then the raw material is fed in at the large end of the mill and the ground product removed at the smaller end, the powder in its progression through the mill is ground by progressively small balls and in consequence the theoretical ideal of a constant ratio between ball size and particle size during grinding is, to some extent, attained.

The type of ball mill illustrated in Fig. 1.3, incorporates a peripheral discharge through line screens lining the cylindrical part of the mill. Heavy perforated plates protect the screens from injury and act as a lining for the tumbling charge; sometimes also the fine screen is further protected by coarse screens mounted directly inside it. This type of mill, which is often known as the Krupp mill, is of interest since it represents a very early type of mill which, with modifications, has retained its popularity. The Krupp mill is particularly suited to the grinding of soft materials since the rate of wear of the perforated liners is then not excessive. At this point it will perhaps be useful to discussthe factors upon which the choice between a ball a tube or a rod mill depends.

When a mill is used as a batch mill, the capacity of the mill is clearly limited to the quantity which can be handled manually; furthermore the mill is, as far as useful work is concerned, idle during the time required for loading and unloading the machine: the load factor thus being adversely affected. Clearly then, there will be a considerable gain in throughput, a saving in handling costs and improved load factor, if the mill operation is made continuous by feeding the material into the mill through one trunnion and withdrawing it either through the other trunnion or through discharge ports at the exit end of the mill body.

Since, however, the flow of powder through the mill is now continuous, it is necessary that the mill body is of such a length that the powder is in the mill for a time sufficiently long for the grinding to be carried to the required degree of fineness. This, in general, demands a mill body of considerable length, or continuous circulation with a classifier, and it is increased length which gives rise to the tube mill.

In the metallurgical industries very large tonnages have to be handled and, furthermore, an excess of fine material is undesirable since it often complicates subsequent treatment processes. In such applications a single-stage tube mill in circuit with a product classifier, by means of which the material which has reached optimum fineness is removed for transport to the subsequent processing and the oversize is returned to the mill for further grinding, is an obvious solution. Once continuous feed and a long mill body have been accepted, however, the overall grinding efficiency of the mill may be improved by fairly simple modifications.

As has already been mentioned; for optimum grinding conditions there is a fairly definite ratio of ball size to particle size and so the most efficient grinding process cannot be attained when a product with a large size range is present in the mill. If, however, a tube mill is divided into a number of compartments and the mean ball size of the grinding media decreases in each succeeding compartment; then the optimum ratio between ball size and particle size is more nearly maintained, and a better overall performance of the mill is achieved; this giving rise to the compartment mill shown in Fig. 1.6. The tube mill has the further advantage that, to some extent, the grinding characteristics of the mill are under control; for example, an increase in the size of the balls in the final chamber will reduce the rate of grinding of the finer fractions but will leave the rate of grinding of the coarser fractions sensibly unchanged and so the amount of coarse material in the final product will be reduced without any excessive overall increase in fineness.

The principal field of application of the rod mill is probably as an intermediate stage between the crushing plant and the ball mills, in the metallurgical industries. Thus, material between about 1-in. and 2-in. size may be reduced to about 6 mesh for feeding to the ball mills. Rod mills are, however, being used in closed circuit with a classifier to produce a product of less than about 48-mesh size, but such applications are unusual.

ball milling

ball milling

A method of grinding particles in ceramic powders and slurries. A porcelain vessel filled with porcelain pebbles tumbles and particles are ground between colliding pebbles. Details A device used to reduce the particle size of materials, bodies or glazes. A ball mill is simply a container that is filled with pebbles (either of porcelain or stones e.g. Flint) into which a charge (powder or slurry) is put and that is then mechanically rotated to cause the tumbling pebbles to crush particles that happen between them. Ball mills can be continuous or periodic, they can be small or gigantic, low speed or high speed, rotated or vibrated or both. For maximum efficiency a ball mill should be made of, or lined with, a porcelain or other very hard surface (so grinding also occurs between the wall and the balls), the balls should be of a range of sizes (to maximize points of contact), the mill should have the correct quantity of balls, the slurry should be the right viscosity and the charge should be an optimal amount (over charging reduces efficiency). Various compromises are often made (for example rubber lined mills to reduce wear and noise). Large manufacturers hire ball mix supervisors, operators and mechanics. Technicians occupy themselves with getting a consistent and predictable product (surface area and particle size distribution), they employ mathematical formulas to determine the amount of balls needed, distribution of ball sizes and other operating parameters like duration and speed. They are wary of grinding products as mixes, it is often better to mill hard and soft powders separately and combine them later. Engineers typically use surface area measurement instrumentation to evaluate mill efficiency. Ball mills can reduce particles to the nano sizes, the process is very important in creating powders used in hi-tech industries (e.g. alumina). Ball mills are slow compared to other methods of grinding, it could take hours, for example, to grind all the particles in a clay to minus 200 mesh. Industrial mills seeking nano-sizes might run 24 hours or more! Ball milling is normally done in consort with wet screening and/or roller-milling/air floating, for example, so that large particles have already been removed by the time the material reaches the ball mill. Air floating can also be done in consort with dust ball milling. The milling process can also reduce particle sizes by too much for an application, so a means of measuring the distribution of ultimate particles is important to be able to set the parameters for the process. A clay body that has been ball milled will be more plastic, potentially much more plastic. Ball milling of the body or selected body materials will reduce or eliminate many types of fired glaze imperfections (especially specking, blistering and pin-holing). That being said and as already noted, iron particulates are best removed before milling). Milling a glaze will produce a cleaner fired result with less imperfections. Materials deliver their chemistry to the glaze melt only if their particles dissolve in the melt. But some glaze materials are refractory and resistant to dissolving (e.g. silica, alumina). When silica does not completely dissolve in a transparent glaze it will fire cloudy and its actual thermal expansion will be higher than it would otherwise be. By ball milling silica to very small particle sizes all the particles dissolve, producing a much better fired product. Milling of slurries presents less technical challenges than dust milling. We have found that thicker creamy slurries mill better than watery ones. A simple ball mill can be constructed by almost anyone, but obtaining the hard pebbles with the correct range of sizes for inside the mill can be challenge (they are expensive). Related Information How long do you need to ball mill a glaze? You can measure to see. How? Wash a measured amount through a 200 mesh screen and note the amount of residue. These two show the oversize on a 200 mesh screen of 100 grams of glaze slurry. On the left: Unmilled. On the right: Milled 1 hour. Clearly it needs more than 1 hour in this mill. A factor here is the high percentage of silica in this recipe. And the fact that US Silica #95 rather than #45 was used. DIY wheel mount ball mill rack Courtesy of Lawrence Weathers Ball mill jar and rack made by @andygravesstructures Make your own ball mill rack - Front side Possible to grind your own ceramic grade rutile? Yes, the granular and powdered grades are the same material. But grinding it is very difficult. Commercial ceramic grade powder is minus 325 mesh, the companies doing this obviously have very good grinding equipment. They also have patience because even in this efficient porcelain ball mill, 90 minutes was only enough to get 50% to minus 325 mesh! The color of the powder is a good indication of its quality, the finer the grind the lighter will be the tan coloration. Particle size drastically affects drying performance These DFAC testers compare the drying performance of Plainsman A2 ball clay at 10 mesh (left) and ball milled (right). This test dries a flat disk that has the center section covered to delay its progress in comparison to the outer section (thus setting up stresses). Finer particle sizes greatly increase shrinkage and this increases the number of cracks and the cracking pattern of this specimen. Notice it has also increased the amount of soluble salts that have concentrated between the two zones, more is dissolving because of the increased particle surface area. Can we ball mill a clay and make it more colloidal? Yes. This 1000 ml 24 hour sedimentation test compares Plainsman A2 ball clay ground to 10 mesh (left) with that same material ball milled for an hour (right). The 10 mesh designation is a little misleading, those are agglomerates. When it is put into water many of those particles break down releasing the ultimates and it does suspend fairly well. But after 24 hours, not only has it settled completely from the upper section but there is a heavy sediment on the bottom. But with the milled material it has only settled slightly and there is no sediment on the bottom. Clearly, using an industrial attrition ball mill this material could be made completely colloidal. Links URLs http://www.thecementgrindingoffice.com/typesofballmills.html Types of Ball Mills Articles Make Your Own Ball Mill Stand Pictures of a ball mill rack that you can make yourself Articles Ball Milling Glazes, Bodies, Engobes Industries ball mill their glazes, engobes and even bodies as standard practice. Yet few potters even have a ball mill or know what one is. By Tony Hansen Tell Us How to Improve This Page Or ask a question and we will alter this page to better answer it. Email Address Name Subject Message Content of message Prove you are not a robot: Enter this text (CAPITAL letters only) or Refresh https://digitalfire.com, All Rights Reserved Privacy Policy

A device used to reduce the particle size of materials, bodies or glazes. A ball mill is simply a container that is filled with pebbles (either of porcelain or stones e.g. Flint) into which a charge (powder or slurry) is put and that is then mechanically rotated to cause the tumbling pebbles to crush particles that happen between them. Ball mills can be continuous or periodic, they can be small or gigantic, low speed or high speed, rotated or vibrated or both. For maximum efficiency a ball mill should be made of, or lined with, a porcelain or other very hard surface (so grinding also occurs between the wall and the balls), the balls should be of a range of sizes (to maximize points of contact), the mill should have the correct quantity of balls, the slurry should be the right viscosity and the charge should be an optimal amount (over charging reduces efficiency). Various compromises are often made (for example rubber lined mills to reduce wear and noise). Large manufacturers hire ball mix supervisors, operators and mechanics. Technicians occupy themselves with getting a consistent and predictable product (surface area and particle size distribution), they employ mathematical formulas to determine the amount of balls needed, distribution of ball sizes and other operating parameters like duration and speed. They are wary of grinding products as mixes, it is often better to mill hard and soft powders separately and combine them later. Engineers typically use surface area measurement instrumentation to evaluate mill efficiency. Ball mills can reduce particles to the nano sizes, the process is very important in creating powders used in hi-tech industries (e.g. alumina). Ball mills are slow compared to other methods of grinding, it could take hours, for example, to grind all the particles in a clay to minus 200 mesh. Industrial mills seeking nano-sizes might run 24 hours or more! Ball milling is normally done in consort with wet screening and/or roller-milling/air floating, for example, so that large particles have already been removed by the time the material reaches the ball mill. Air floating can also be done in consort with dust ball milling. The milling process can also reduce particle sizes by too much for an application, so a means of measuring the distribution of ultimate particles is important to be able to set the parameters for the process. A clay body that has been ball milled will be more plastic, potentially much more plastic. Ball milling of the body or selected body materials will reduce or eliminate many types of fired glaze imperfections (especially specking, blistering and pin-holing). That being said and as already noted, iron particulates are best removed before milling). Milling a glaze will produce a cleaner fired result with less imperfections. Materials deliver their chemistry to the glaze melt only if their particles dissolve in the melt. But some glaze materials are refractory and resistant to dissolving (e.g. silica, alumina). When silica does not completely dissolve in a transparent glaze it will fire cloudy and its actual thermal expansion will be higher than it would otherwise be. By ball milling silica to very small particle sizes all the particles dissolve, producing a much better fired product. Milling of slurries presents less technical challenges than dust milling. We have found that thicker creamy slurries mill better than watery ones. A simple ball mill can be constructed by almost anyone, but obtaining the hard pebbles with the correct range of sizes for inside the mill can be challenge (they are expensive).

You can measure to see. How? Wash a measured amount through a 200 mesh screen and note the amount of residue. These two show the oversize on a 200 mesh screen of 100 grams of glaze slurry. On the left: Unmilled. On the right: Milled 1 hour. Clearly it needs more than 1 hour in this mill. A factor here is the high percentage of silica in this recipe. And the fact that US Silica #95 rather than #45 was used.

Yes, the granular and powdered grades are the same material. But grinding it is very difficult. Commercial ceramic grade powder is minus 325 mesh, the companies doing this obviously have very good grinding equipment. They also have patience because even in this efficient porcelain ball mill, 90 minutes was only enough to get 50% to minus 325 mesh! The color of the powder is a good indication of its quality, the finer the grind the lighter will be the tan coloration.

These DFAC testers compare the drying performance of Plainsman A2 ball clay at 10 mesh (left) and ball milled (right). This test dries a flat disk that has the center section covered to delay its progress in comparison to the outer section (thus setting up stresses). Finer particle sizes greatly increase shrinkage and this increases the number of cracks and the cracking pattern of this specimen. Notice it has also increased the amount of soluble salts that have concentrated between the two zones, more is dissolving because of the increased particle surface area.

This 1000 ml 24 hour sedimentation test compares Plainsman A2 ball clay ground to 10 mesh (left) with that same material ball milled for an hour (right). The 10 mesh designation is a little misleading, those are agglomerates. When it is put into water many of those particles break down releasing the ultimates and it does suspend fairly well. But after 24 hours, not only has it settled completely from the upper section but there is a heavy sediment on the bottom. But with the milled material it has only settled slightly and there is no sediment on the bottom. Clearly, using an industrial attrition ball mill this material could be made completely colloidal.

choosing ball milling media for firework chemical milling skylighter, inc

choosing ball milling media for firework chemical milling skylighter, inc

In his book Ball Milling Theory and Practice for the Amateur Pyrotechnician, Lloyd includes a section on casting your own lead media. Some folks melt used lead automobile wheel weights or hardened linotype as the raw material for casting media. Lloyd does begin this chapter with the warning, though: "Casting metals is dangerous. If you don't have experience, make up the molds, then seek a plumber or firearms reloader for assistance." There are other types of media as well. Here's a shot of some stainless steel media and ceramic media. The stainless steel must be spark-resistant, non-magnetic steel in the 300-series. Alloys 304 and 316 are the most common stainless steels of this type. High-density alumina ceramic media is the type I've heard of most often being used in ball mills.

ball mills - the ceramic shop

ball mills - the ceramic shop

In ceramics, ball mills are used to grind down materials into very fine particles. Materials such as clay and glaze components can be broken down in a ball mill by getting placed into rotating or rolling jars with porcelain balls inside them. During milling, the porcelain balls pulverized the materials into an incredibly fine powder. Ball mills can be used to further break down or refine a single material, or you can place multiple materials into a ball mill jar to mix as you pulverize -- this is a very common industrial solution for mixing glazes that require the smallest of mesh sizes. Ball mills basically function like a mortar and pestle, but on a much larger scale.

Here at The Ceramic Shop, we carry ball mills and accessories produced by strong and reliable Shimpo. Shimpo's line of heavy duty ball mills allow for very precise grinding and mixing of both dry and wet materials. The porcelain jars are available in a variety of sizes, ranging from one liter to ten liters in capacity, so you can really customize your ball mill outfit to suit your needs. If you are a potter working out of your home or a shared studio, and dont have the space or budget for a full-scale ball mill setup, consider Shimpos ball mill wheel attachment -- this ingenious setup allows you to turn any standard potters wheel into a makeshift ball mill!

grinding cylpebs

grinding cylpebs

Our automatic production line for the grinding cylpebs is the unique. With stable quality, high production efficiency, high hardness, wear-resistant, the volumetric hardness of the grinding cylpebs is between 60-63HRC,the breakage is less than 0.5%. The organization of the grinding cylpebs is compact, the hardness is constant from the inner to the surface. Now has extensively used in the cement industry, the wear rate is about 30g-60g per Ton cement.

Grinding Cylpebs are made from low-alloy chilled cast iron. The molten metal leaves the furnace at approximately 1500 C and is transferred to a continuous casting machine where the selected size Cylpebs are created; by changing the moulds the full range of cylindrical media can be manufactured via one simple process. The Cylpebs are demoulded while still red hot and placed in a cooling section for several hours to relieve internal stress. Solidification takes place in seconds and is formed from the external surface inward to the centre of the media. It has been claimed that this manufacturing process contributes to the cost effectiveness of the media, by being more efficient and requiring less energy than the conventional forging method.

Because of their cylindrical geometry, Cylpebs have greater surface area and higher bulk density compared with balls of similar mass and size. Cylpebs of equal diameter and length have 14.5% greater surface area than balls of the same mass, and 9% higher bulk density than steel balls, or 12% higher than cast balls. As a result, for a given charge volume, about 25% more grinding media surface area is available for size reduction when charged with Cylpebs, but the mill would also draw more power.

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