The basic types of commonly used ball mill in the production are grate mill, overflow ball mill. Jiangsu Zhongbo ball mill is widely used as the fine grinding machine, and the utility model is characterized by : adaptability, large production capacity, to meet the needs of industrial production; big crushing ratio, fineness of pulverized materials can be adjusted according to need; not only can dry but also wet work, drying and milling operation can be carried out at the same time, to the mixture grinding and homogenizing effects; closed system can achieve the aseptic requirements; and has the advantages of simple structure, reliable operation, easy to repair. Grate Mill Grate type ball mill belongs to low level forced discharge type grinding equipment. Mill cylinder body store little pulp, finely ground particles can be discharged in time, therefore less likely to happen over-mill. At the same time because of the lattice board stopped, mill can be loaded with more balls, also easy to put the ball, thereby which increases the grinding area and unit time of impact crushing frequency during grinding process. So the mill has strong grinding capability, and in the mill cylinder body pulp liquid level is low, that has weak buffer action on the ball falling.Thus the productivity of grate type ball mill is 10% - 15% higher than overflow type ball mill with the same specifications , and the grinding efficiency is higher than the latter,too. However, as the grate type ball mill discharging speed is fast, the material in the mill stay a short time, the grain size of the products is relatively thick, therefore grate type ball mill is widely apply to coarse grinding , or used in grinding operations that ground materials is prone to mud. Overflow Type Ball Mill Overflow ball mill structure and the structure of the lattice-type ball mill is basically the same, the difference between the two is mainly the discharge end structure. Compared with grate type ball mill, due to that the overflow type ball mill 's fine product are discharged from the hollow shaft neck by overflowing out, the grinding particle size is relatively small, with same equipment specifications production rate is small, grinding process have serious crushed phenomenon , the grinding efficiency is distinctly lower; but because the overflow type ball mill has the advantages of simple structure, low cost and suitable for fine grinding equipment, so at the same ,the overflow type ball mill in the production practice has been widely adopted ,too.