Classification and working principle of fireball m

2022-08-14
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Classification and working principle of ball mill

1. Classification according to the ratio of cylinder length to diameter

(1) when the length diameter ratio of short mill is less than 2, it is a short mill, or a ball mill. Generally, it is a single bin, which is used for rough grinding or primary grinding, and billiard mills can also be used in series

(2) medium length mill is medium length mill when the length diameter ratio is about 3

(3) when the length bar of the long mill is more than 4, it is a long mill or tube mill. Medium and long mills are generally divided into warehouses. It is widely used in cement production

2. Classification 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 sections. This kind of mill is the most commonly used

(2) the rod mill is loaded with automatic and manual modes with a diameter of mm to obtain the experimental results, and the steel rod is used as the grinding medium. The ratio of cylinder length to diameter of rod mill is generally 1

(3) baseball mill this kind of mill usually has a bin. Cylindrical steel rods are loaded into the first bin as the grinding medium, and then steel balls or steel sections are loaded into each bin. The length diameter ratio of the baseball mill should be about 5, and the ratio of the rod bin length to the effective diameter of the mill should be 1 5, the rod length is about 100mm shorter than the rod bin, so as to facilitate the parallel arrangement of steel rods and prevent cross and disordered rods

(4) the grinding medium loaded in the gravel mill is gravel, pebble, porcelain ball, etc. Granite and porcelain are used as lining plates. It is used in the production of white or colored cement and ceramics

3. Classification according to the unloading method

(1) the materials to be milled by the tail discharge mill are fed from one end of the mill and unloaded from the other end, which is called the tail discharge mill

(2) the materials to be milled by the intermediate discharge mill are fed from both ends of the mill and unloaded from the middle of the mill barrel, which is called the intermediate discharge mill. This kind of mill is equivalent to two ball mills used in parallel, so the equipment is compact and the process is simplified. According to the discharge mode of the tail discharge mill, there are many types of grid discharge, overflow discharge, peripheral discharge and wind discharge

4. According to the transmission mode, the hydraulic oil will oxidize and coking in long-term work (1) the central drive mill motor drives the hollow shaft at the discharge end of the mill through the reducer to drive the mill body to rotate. The output shaft of the reducer is in line with the centerline of the mill

(2) the edge drive mill motor drives the big gear fixed on the discharge end cylinder through the reducer to drive the mill cylinder to rotate

5. Other classifications

according to the process operation, it can be divided into dry mill, wet mill, intermittent mill and continuous mill. Compared with the clearance mill, the continuous mill has high output, low power consumption per unit weight, high degree of mechanization and less operators, except for a series of problems caused by components. However, the capital construction investment cost is large and the operation and maintenance are complex. At present, intermittent mills are rarely used and are often used as laboratory mills

(II) working principle of the mill:

the ball mill is mainly composed of cylindrical cylinder, end cover, bearing and transmission big gear ring and other components. The cylinder is filled with steel balls or steel rods with a diameter of mm, which is called grinding medium, and its loading amount is 25% - 50% of the volume of the whole cylinder. There are end caps at both ends of the cylinder. The end caps are connected with the end flanges of the cylinder by screws. There is a hole in the middle of the end cap, which is called a hollow journal. The hollow journal is supported on the bearing, and the cylinder can rotate. The cylinder is also fixed with a big gear ring. In the drive system, the motor drives the big gear ring and 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 or leaks down in a parabola Due to the hollow Journal on the end cover, the material is fed into the cylinder from the hollow Journal on the left of the upper and lower yield points corresponding to the stress respectively, and gradually diffuses and 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 smash the material, while some steel balls grind the material in the leaking state of the cylinder, and the whole moving process is also the crushing process of the material

a ball mill is equipped with a grid plate at the right end (discharge end). The grid plate consists of several fan-shaped grate holes with a width of mm, which is generally mm. Materials can enter the space between the grid plate and the end cover through the grate holes, and then the materials are lifted up by the lifting plate 2. The materials slide down along the lifting plate through the conical block to the right to the hollow journal, and then discharged out of the machine by the hollow journal

the other way is to discharge the materials in the pneumatic discharge ball mill. The materials enter the ball mill from the feeding port. With the rotation of the mill, the grinding medium (steel ball) in the mill impacts and grinds the materials, and the materials gradually move from the left end (inlet) of the mill to the right end. In the moving process, that is, the crushing and grinding process of materials. The outlet end of the ball mill is connected with the air pipe, and the inlet of the powder concentrator, air separator, dust collector and fan are connected in series in the pipeline system. When the wind system is started, the ball mill body is also in low negative pressure operation. When the ground materials become loose with the rotation of the mill and enter the pipeline system from the discharge port with the wind force, the coarse particles are separated by the powder concentrator and then sent to the inlet of the ball mill. The fine powder is separated and recycled by the separator, and the gas is discharged into the atmosphere by the fan

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