What is a ball mill and what is its use? Please help me solve it ~

Selection and design of ball mills (including rod mills and tube mills) Section 1 Classification and working principle of mills Section 1 Classification of materials of mills Section 1 The particle size of materials crushed by crushing machines (coarse, medium and fine crushing) is 8-20 mm. In order to meet the fineness requirements of production technology, the crushed materials must be finely crushed by crushing machines. Grinding is an important process in modern industrial production. Grinding operations are needed in mineral processing, building materials, cement, coal, chemical industry, electric power, light industry, metallurgy and other industrial sectors. Ball mill, vibration mill, jet mill and other mills are one of the important equipments in these industrial sectors. Ball mill is the most widely used. The main part of this pulverizer is a slowly rotating cylinder filled with grinding media. The ball mill has the advantages of simple and firm structure, reliable operation, simple maintenance and management, long-term continuous operation, strong adaptability to materials, large crushing ratio (up to more than 300) and large production capacity, which can meet the needs of modern large-scale industrial production. However, the shortcomings of ball mill are also obvious, such as low working efficiency, large volume, large consumption of grinding body and liner, and loud noise during operation. Therefore, when selecting grinding machinery, we should consider the physical properties of materials, grinding requirements of materials, operating conditions, production environment, mechanical energy consumption, work efficiency, capital investment and other factors before making a decision. Because each grinder has its limitations, advantages and disadvantages, it is necessary to make a comprehensive comparison and choose the most reasonable grinder according to the above requirements when selecting equipment. 1. Classification according to the length-diameter ratio of cylinders (1) Short grinding is short grinding or ball mill when the length-diameter ratio is below 2. Generally, it is a single bin, which is used for rough grinding or primary grinding, or 2-3 ball mills can be used in series. (2) The medium-long mill is a medium-long mill when its length-diameter ratio is about 3. (3) When the length-diameter ratio of the long mill is above 4, it is a long mill or a tube mill. Medium-long mill and long mill are generally divided into 2-4 silos. It is widely used in cement plants. 2. According to the shape of the grinding medium loaded in the mill (1), the grinding medium loaded in the ball mill is mainly steel balls or steel segments. This kind of mill is the most commonly used. (2) Put a steel bar with a diameter of 50-100 mm into a bar mill as a grinding medium. The length-diameter ratio of the barrel of a rod mill is generally 1.5-2. (3) Rod ball mill This mill usually has 2-4 silos. The first silo is filled with cylindrical steel bars as grinding media, and then each silo is filled with steel balls or sections. The length-diameter ratio of the bar ball mill should be about 5, the ratio of the length of the bar bin to the effective diameter of the mill should be between 1.2- 1.5, and the length of the bar is about 100mm shorter than that of the bar bin, so as to facilitate the parallel arrangement of steel bars and prevent cross and disorderly bars. (4) The grinding media filled in the gravel mill include gravel, pebbles, porcelain balls, etc. Granite and porcelain are used as linings. Used to produce white or colored cement and ceramics. 3. According to the unloading mode (1), the materials to be ground in the tailings mill are fed from one end of the mill and discharged from the other end, which is called tailings mill. (2) The materials to be ground in the middle unloading mill are fed from both ends of the mill and discharged from the middle of the mill barrel, which is called the middle unloading mill. This mill is equivalent to using two ball mills in parallel, with compact equipment and simplified technology. There are many types of discharging methods for the tail mill, such as grid discharging, overflow discharging, peripheral discharging and wind discharging (see figure 1- 1, figure 1-2, table 1- 1). Figure 1- 1 Classification of ball mills (1) Short cylindrical shape (grid discharge); (b) Long cylindrical shape (overflow discharge); (c) Long cylindrical shape (peripheral discharge); Cone (wind or overflow discharge); (e) Tubular (grid discharge) drawing 1-2 rod mill (I) Overflow type; (b) peripheral discharge type; (c) Intermediate peripheral layout table 1- 1 mill classification table?

Arrangement mode of barrel length-diameter relationship of medium-sized mill in grinding mill

Ball mill steel ball (section steel) short tube L < 2d 1. Overflow drain 2. Grid discharge

L=-3D 1。 Overflow drain 2. Grid discharge.

Long tube L≥4D 1. Overflow drain 2. Gate discharge 3. Discharge in the middle of the bucket.

Conical overflow L=(0.25- 1)D

Barrel shape of steel bar of rod mill L≤2D 1. Overflow drain 2. Peripheral discharge 3. Peripheral discharge 4. According to the classification of transmission modes (1), the central drive motor drives the hollow shaft at the discharge end of the mill through the reducer to drive the grinding body to rotate. The output shaft of the reducer is in a straight line with the center line of the mill. (2) The electromechanical motor of the edge drive mill drives the big gear fixed on the barrel of the discharge end through the reducer to drive the barrel of the mill to rotate. 3. Other classifications can be divided into dry grinding, wet grinding, intermittent grinding and continuous grinding according to process operation. Compared with the gap mill, the continuous mill has high output, low power consumption per unit weight of products, high degree of mechanization and few operators. However, the capital construction investment cost is high and the operation and maintenance are complicated. At present, intermittent mills are rarely used, and they are often used as laboratory test mills. Second, the working principle of the mill The ball mill is mainly composed of a cylindrical barrel 1, an end cover 2, a bearing 3 and a transmission gear ring 4. The cylinder 1 is filled with steel balls or steel bars with a diameter of 25- 150mm, which is called grinding medium, and its loading is 25%-50% of the whole cylinder volume. There are end covers 2 at both ends of the cylinder, which are connected with the flange at the end of the cylinder by screws. There is a hole in the middle of the end cover, which is called hollow journal. The hollow journal is supported on the bearing 3, and the cylinder can rotate. The big gear ring 4 is also fixed on the cylinder. In the drive system, the motor drives the big gear ring and the cylinder to rotate slowly through the coupling, reducer and pinion. When the cylinder rotates, the grinding medium rises to a certain height with the cylinder wall, and then falls parabolically or pours down, as shown in the right figure of Figure 1-3. Due to the hollow journal on the end cover, the material enters the cylinder from the left hollow journal and gradually moves to the right. When the material moves from left to right, the rotating cylinder brings the steel ball to a certain height and falls down to crush the material, while part of the steel ball grinds the material when it falls down from the cylinder, and the whole movement process is also the crushing process of the material. In the working principle of the ball mill shown in Figure 1-3, due to the rotation of the cylinder and the movement of the grinding medium, the material gradually diffuses to the right and finally overflows from the hollow journal on the right. This type of ball mill is called overflow ball mill. Another ball mill is equipped with a grate plate at the right end (discharge end) (see figure 1-4). The grate plate consists of several fan-shaped grate holes. The width of the grate holes on the fan-shaped plate is 7-20mm, usually 7-8 mm. Materials can enter the space between the grate plate and the end cover through the grate holes and then be lifted by the lifting plate. Fig. 1-3 schematic diagram of ball mill 1- cylinder; 2- end cover: 3- bearing; 4-Large gear ring diagram 1-4 grid ball mill1-grid plate; 2— The third method of lifting plates is air unloading, as shown in figure 1-5, which is an air unloading ball mill. Materials enter the ball mill from the feed inlet 1. With the rotation of the mill, the grinding medium (steel ball) in the mill impacts and grinds the materials, and the materials move from the left end (inlet) of the mill to the right end one by one, that is, the process of material crushing and grinding. The outlet end of the ball mill is connected with an air duct, and the inlet of a classifier, a cyclone separator, a dust collector and a fan are connected in series in the pipeline system. When the wind power generation system is started, the ball mill body is also in a low negative pressure operation state. When the ground material becomes loose with the rotation of the mill and enters the pipeline system from the outlet with the wind, the coarse particles are separated by the powder separator and sent to the inlet of the ball mill, the fine powder is separated and recovered by the powder separator, and the gas is discharged into the atmosphere by the fan. When the filling rate of steel balls (the volume of all steel balls accounts for 40%-50% of the internal volume of the cylinder) and the ball mill rotates at different speeds, the grinding medium in the cylinder may have three basic motion states. In the first case, as shown in figure 1-6(a), if the rotating speed is too high, the steel ball will rotate with the cylinder by centrifugal force, and the whole steel ball will form a ring close to the inner wall of the cylinder, which is called "overturning state", so the grinding medium cannot impact and grind the material. In the second case, as shown in figure 1-6(b), when the rotating speed is too slow, the rotation of materials and grinding media along the mill will only rise to 40-50 (there is also relative sliding between layers during the rising period, which is called slipping). When the friction between the grinding medium and material and the cylinder is equal to the dynamic friction angle, the friction medium and material will slide down, which is called "sliding state". It has grinding effect on materials, but has no effect on materials, thus making grinding efficiency poor. In the third case, as shown in figure 1-6(c), the mill speed is moderate. After the grinding medium is lifted to a certain height by the air cylinder, it leaves the circular track and falls freely along the parabolic trajectory, which is called "falling state". The steel ball falling along the parabolic trajectory impacts and grinds the steel ball located at the lower part of the cylinder or cylinder liner, so that the material is crushed. Fig. 1-5 air outlet ball mill 1- inlet; 2- sealing device; 3 cylinders; 4- asbestos pad; 5- felt; 6- end cover; 7— Drawing of discharge port 1-6 What is the relationship between cylinder speed and grinding body movement? Structure of ball mill

Ball mills are divided into many types due to different specifications, discharging and transmission modes, but the main structures are basically the same. Figure 1-7 shows the structure of lattice ball mill, figure 1-8 shows the structure of overflow rod mill, and figure 1-9 shows the structure of tube mill. The ball mill is mainly composed of cylindrical cylinder, liner, compartment plate (only in multi-compartment mill), main bearing, feeding and discharging device and transmission system. First, the body part 1. Cylinder (including main bearing, see Figure 1- 10) The cylinder of ball mill is one of the main working parts of ball mill. When the cylinder works, it not only bears the static load of the grinding body, but also bears the impact of the grinding body. The cylinder is rotating, so alternating stress is generated on the cylinder. Therefore, it must have sufficient strength and rigidity. This requires that the metal materials used to manufacture the barrel should have high strength, good plasticity and good mechanical properties to ensure the safe operation of the barrel. Figure 1-7 lattice ball mill 1- feeder; 2- feed pipe; 3— Main bearing; 4— Sector gasket; 5- end cover; 6-cylinder; 7— Cylinder liner; 8— Manhole; 9— Wedge weld bead; 10- center liner; 1 1- discharge grid plate; 12- big gear ring; 13- end cover; 14-cone; 15-wedge iron; 16- elastic coupling; 17- motor; 18- transmission shaft drawing 1-8 overflow rod mill 1- cylinder; 2— End cover of feed end; 3- big gear ring; 4- bearing; 5-gasket; 6- Feeder; 8— Feed pipe; 9— Discharge pipe; 10-flange; 1 1- manhole diagram 1-9 tube mill structure 1- discharge end cover; 2- transmission connecting pipe; 3- Chessboard; 4- lifting plate; 5-discharge spiral blade; 6-cylinder screen; 7— Exhaust hood; I, II and III— The materials used to manufacture the first, second and third silos are generally ordinary structural steel, and the strength, plasticity and weldability of this material meet the requirements. With the development of industry, the capacity (output) of the mill is also developing towards large scale. The barrel of the recently designed large mill is made of 16Mn steel. Its elastic strength limit σ is about 50% higher than Q235, its corrosion resistance is 50% higher than Q235, and its impact toughness (especially at low temperature) is much higher than Q235. In addition, 16Mn has good machinability, weldability, wear resistance and fatigue resistance. Therefore 16Mn is a suitable steel. When the mill is running and stopped for a long time, the length of the cylinder is different. This is due to the thermal expansion and cold contraction caused by different cylinder temperatures. Therefore, in the design, installation and maintenance, the characteristics of thermal expansion and cold contraction of the cylinder must be considered. In general, the discharge end of the mill is close to the transmission device. In order to ensure the normal meshing of gears, there is no axial movement at the discharge end, so there is a structure at the feed end to adapt to axial thermal deformation. There are two ways to consider the axial thermal deformation of the cylinder in the mill structure: one is to consider the reserved gap (a, b) between the hollow journal shoulder and the bearing, as shown in figure 1- 1 1. The other is to install several steel bars horizontally between the bearing seat and the bottom plate, as shown in figure 1- 12. When the cylinder expands with heat and contracts with cold, the main bearing seat at the feed end can move along the cylinder. Figure 1- 10 wet ball mill main bearing 1- bearing chassis; 2- spherical tile seat; 3- locating pin; 4- spherical tiles; 5— Bearing cover; 6- Screw Diagram1-1/reserved clearance diagram of axial thermal deformation of ball mill cylinder 1- 12 Each silo on the cylinder shall be provided with a grinding door (also called manhole). The function of the grinding door is to insert and replace the lining plate and compartment plate, fill or pour out the grinding body, stop grinding and check the situation in the grinding room. Sliding bearing is the most commonly used main bearing of ball mill, with large diameter but short length, as shown in figure 1- 10. The bearing bush is cast with babbit alloy. The difference between it and ordinary sliding bearing is that only the lower half has bearing bush. The whole bearing is made of cast iron except that the bearing bush is made of babbitt alloy. Because of the large span and heavy load of the ball mill, it will bend to a certain extent, and because of the manufacturing and assembly errors, it is difficult to ensure accurate coaxiality. Therefore, the bearing is made into automatic positioning type, and the spherical tile seat 2 and the spherical tile 4 can move relatively with the spherical center as the rotation center, so that the load acting on the bearing bush is evenly distributed. A locating pin 3 is also arranged between the ball shoe seat 2 and the ball shoe 4 to limit the moving range of the ball shoe. During installation, the screw 6 can be used to adjust the position of the ball bearing 2. It can also be adjusted with a wedge. Main bearing is the key component of ball mill, and its lubrication must be paid full attention to. Generally, thin oil centralized circulation lubrication is adopted, and some minicomputers adopt oil ring lubrication, oil ring dripping lubrication or wool lubrication. 2. Cylinder liner (1) The material and function of cylinder liner are used to protect the cylinder from direct impact and friction of grinding body and material; At the same time, different types of liners can be used to adjust the motion state of the grinding body, so as to enhance the crushing effect of the grinding body on materials, help improve the grinding efficiency of the mill, increase the output and reduce the metal consumption. Most of the lining plates of ball mills are metal materials, and a few are non-metal materials. The cylinder liner not only protects the cylinder block, but also affects the movement law of the grinding body. In order to meet the requirements of different working conditions (crushing or fine grinding), the shape and material of the liner are also different. When crushing is the main method, the liner is required to have strong compaction ability and good impact resistance to the grinding body. High manganese steel 2GMn 13 has enough impact toughness, and its surface can be cold-worked and hardened to become hard and wear-resistant when subjected to certain impact. Therefore, high manganese steel is mostly used as the lining plate of mill barrel, which is mainly grinding. When fine grinding is the main method, the protrusion of the liner is relatively small, which has a weak pushing effect on the grinding body, a small impact and a strong grinding effect. The lining is required to have good wear resistance. In China, the lining materials of the mill barrel, which mainly focus on fine grinding, are generally wear-resistant white iron, chilled cast iron, medium manganese rare earth nodular cast iron and so on. In recent years, rubber gasket has been widely used. The shape of rubber liner generally consists of two parts: rubber batten and flat liner. According to the different working conditions of the mill (crushing or fine grinding), the pressing strips of the rubber liner are also made into different shapes to change the motion law of the grinding body in the mill (impact or grinding). (2) Advantages and disadvantages of rubber gasket A. Wear resistance. Because rubber has good elasticity and can be deformed when it is hit by steel balls, the stress is small. For soft materials, the life of rubber liner is 2-3 times that of manganese steel liner, and the higher the hardness of the material, the more obvious the advantages of rubber liner. B. corrosion resistance. Steel liner can be corroded by acidic slurry, while rubber liner is insensitive to acidic or alkaline medium, water and steam at a certain temperature, and only oil and ozone (produced by high-power motor) can corrode it. C. easy disassembly and assembly. Due to the light weight of rubber liner, the quality of rubber liner with the same specification is only 1/5- 1/6 of manganese steel liner. Therefore, it is convenient to disassemble and assemble, and the time for installing the rubber liner is only 1/3- 1/4 of that of the steel liner. When replacing the steel lining, it is often necessary to remove all the steel balls, but it is not necessary to replace the rubber lining. D. easy to maintain. When using steel liner, it is often necessary to check the screws, while rubber liner rarely leaks the screws. E. The rubber liner becomes thinner and the effective volume of the cylinder increases. The thickness of the lining is usually only 50 mm. The blocking phenomenon of rubber discharge grid plate is less than that of steel grid plate. G. the rubber liner has low noise when working. The disadvantage of rubber liner is that it is not resistant to high temperature and is not suitable for dry grinding. (3) Type of Liner The most common wear phenomenon of the liner of a mill is the formation of grooves. In order to avoid this situation, various improvements have been made to the surface shape of the mill lining, so that the grinding body falls from one of the distributed chutes. In fact, it is impossible to solve this problem by changing the speed of the mill to keep the grinding body in the correct trajectory, and properly selecting the surface shape of the mill liner is the only way to solve the trajectory of the grinding body. According to the shape of the working face, it can be divided into flat lining, layered lining, convex lining, corrugated lining, stepped lining, hemispherical lining, small corrugated lining (without bolts) and end cover lining. A. Flat lining plate (Figure 1- 13(a)) All lining plates with flat surface or cast patterns are flat lining plates, and their effect on the grinding body basically depends on the static friction between the lining plate and the grinding body, which has a certain lifting effect on the grinding body. The friction coefficient between them is 0.35 in wet grinding and 0.4 in dry grinding. However, the friction coefficient required for the flat lining to lift the grinding body is much larger than the above data. Therefore, when the cylinder rotates, the grinding body will inevitably slide, reducing the rising speed and lifting height of the grinding body. It is precisely because of the sliding phenomenon that the grinding effect of the grinding body is increased. Therefore, the flat liner is suitable for the barrel of the mill, which is mainly fine grinding. B the batten lining board (figure 1- 13(b)) consists of a flat lining board and battens with bolts, and the lining board is fixed by battens (bolts). The battens of this liner are higher than the liner, and the thrust of the battens on the grinding body and the friction of the liner on the grinding body make the grinding body rise higher and have greater impact energy. Therefore, the layered liner is suitable for the barrel of the mill, which is mainly broken (rough grinding). Especially suitable for materials with large particle size and high hardness. The disadvantage of the batten liner is that the height of the ball is uneven, and the grinding body on the front of the batten is very high, while the grinding body far away from the batten slides locally like a flat liner. When the speed of the mill is high, the grinding body on the front side of the pressing strip is taken too high and thrown onto the opposite lining plate, which not only has little crushing effect, but also accelerates the wear of the lining plate and grinding body. It is not suitable to install layered liner in high-speed mill. The main parameters of layered liner are layered height and density. The height of the battens should not exceed the radius of the largest steel ball of the mill (or warehouse). The inclination angle of the battens should be 40-50. The distance between two slats is preferably equal to 3 times the maximum ball diameter of the mill (bin). C. The convex edge liner (Figure 1- 13(c)) is a semicircular or trapezoidal convex edge cast on the flat liner. The function of ribs is the same as that of layering. Good rigidity, not easy to deform, but once the ribs are worn, the whole liner must be replaced, which is not as economical as layered liner. D corrugated liner (fig. 1- 13(d)) flattens the convex edge of the convex liner to form the corrugated liner. The ball carrying capacity of this liner is worse than that of rib liner. In a node, the ascending part is very effective for lifting the grinding body, while the descending part has some adverse effects. The liner is suitable for the rod bin of rod mill or ball mill. E. the surface of the step lining (fig. 1- 13(e)) presents an inclined angle, which is combined with the original friction angle. After installation, it becomes many steps, which can increase the thrust of the liner to the grinding body. The lifting height of the stepped liner for the same layer of steel balls is uniform, and the shape of the liner has no obvious change after the surface is worn, which can prevent the sliding and wear between grinding bodies. The stepped liner is suitable for crushing bins of coarse mills and multi-bin mills. Figure 1- 13 Liner Type (a) Flat Liner; (b) batten lining; (c) ribbed gaskets; Corrugated lining; (e) stepped lining; (f) hemispherical liner; (g) small corrugated gasket; (h) end cap gasket; (i) K-type rubber gasket; (j) Type B rubber liner F. Hemispherical liner (Figure 1- 13(f)) The application of hemispherical liner can completely avoid the circumferential wear groove on the liner, greatly reduce the metal consumption of the grinding body and liner, and increase the production by about 10% compared with the liner with smooth surface. The diameter of the hemisphere should be 2/3 of the maximum steel ball diameter of the mill (silo), the center distance of the hemisphere should not be more than 2 times of the average steel ball diameter of the mill (silo), and the hemisphere should be arranged in a triangle to prevent the steel ball from sliding along the cylinder. G. small corrugated liner (fig. 1- 13(g)) this is a bolt-free liner suitable for fine grinding machine (silo). Its peaks and valleys are very small. The main feature of the graded gasket is that it has an inclined plane along the axial direction. The installation direction in the mill is that the big end faces the grinding tail, that is, the diameter near the feeding end is large and the diameter at the discharging end is small. The shape of the liner will cause the grinding bodies to be automatically classified along the internal channel of the grinder according to their size, so that the grinding bodies with large diameter will remain in the feed end area of the grinder, while the grinding bodies with small diameter will gather on one side near the discharge end of the grinder. In this way, the steel balls are automatically arranged along the axial direction of the mill from large to small, that is, they can be automatically classified, which meets the requirements of the material grinding process. Therefore, it can reduce the number of silos of the mill, increase the effective volume of the mill, reduce ventilation resistance, improve grinding efficiency and output, and reduce power consumption. In order to avoid excessive accumulation of large steel balls or coarse materials at the feed end, a 1-2 liner can be installed near the feed end. In order to prevent small steel balls or materials from being concentrated at the discharge end of the mill, 1-2 rows of liners can be installed near the outlet as flat liners. Grading liner is only applicable to ball silos of ball mills and mills. 1. end cover bushing (fig. 1- 13(h)) the end cover bushing has a flat surface and is bolted to the end cover of the mill to protect the end cover from abrasion by grinding bodies and materials. (4) Specification of the liner The size of the liner should consider the convenience of handling, loading and unloading and entering and leaving the grinding door. In recent years, the size of the mill liner is uniform, with a width of 3 14mm, a full liner length of 500mm, a half liner length of 250mm, a thickness of 40-50mm and a mass of about 45-55. There are two ways to fix the liner: bolt connection and inlay. When fixing the cylinder liner with bolts, make the cylinder liner close to the inner wall of the cylinder, and there shall be no gap. In order to prevent mud or powder from entering the washing cylinder, a washer should be installed between the gasket and the cylinder. In order to prevent the cement slurry from flowing out along the bolt hole, the bolt fixing the lining plate is equipped with a washer with a conical surface (Figure 1- 14). When the nut is tightened, the hemp ring is tightly pressed in the conical washer, so that the gap between the bolt and the cylinder bolt hole is eliminated. To prevent bolts from loosening, double nuts or check washer are needed. Fig. 1- 14 bolt connection of lining plate 1- lining plate; 2- washer; 3 cylinders; 4-bolts and nuts; 5— Spring washer; 6- sealing washer; The advantages of 7-cone full-circle bolt connection and fixation are impact resistance, vibration resistance and reliability. Its disadvantage is that it needs to drill holes in the cylinder, which consumes manpower and material resources, weakens the strength of the cylinder and may also leak materials. Small corrugated liners are usually alternately embedded in the cylinder and squeezed together to form an "arch" structure, which is generally very firm, coupled with the solidification of cement mortar. In order to squeeze tightly, the lining board is wedged with iron plates in the circumferential direction. The structure and installation method of another bolt-free bushing are shown in figure 1- 15. Semi-circular pin holes are arranged on both sides of the inner container. When the bushings are pressed against each other, the wedge pin is driven into the pin hole. When the head and tail linings are connected at each turn, a special wedge pin is driven into the pin hole. Gaskets are added between the liners. Figure 1- 15 Boltless Bushing and Its Installation Method (I) Boltless Bushing Structure; (II) Installation drawing of bolt-less liner The installation of cast stone liner should be staggered and should not be fixed by bolts. Generally, it is embedded in a layer of rubber material, with a thickness of about10 mm. The installation of rubber liner in the mill is shown in figure 1- 16. The rubber batten is placed in the groove of the rubber gasket and firmly connected with the cylinder with splint bolts. Fig. 1- 16 rubber lining installation drawing 1- rubber lining; 2 cylinders; 3— Rubber gasket; 4— Nut; 5— Washer; 6— Rubber washer; 7— Splint bolt; 8— Rubber strip 3. The partition (1) divides the mill into several bins and roughly separates the grinding bodies of various sizes. It is required that the grinding body start with impact action and gradually transition to grinding action in the direction of grinding tail, so as to give full play to the grinding ability of the grinding body. The grate hole of the partition determines the filling degree of the material in the mill and also controls the flow rate of the material in the mill. The separator has the function of screening and analyzing materials, which can prevent too large particles from entering the area with weak impact, otherwise the materials that cannot be crushed will pile up, which will seriously affect the crushing effect, or the materials that have not been crushed will lead to unqualified product fineness.