Cement grinding method

Abstract

The invention relates to a cement grinding method. The cement grinding method comprises the following steps that (1), an external circulation vertical mill preliminarily crushes cement raw materials and then feeds the crushed cement powder into a vibration screening device; (2), the vibration screening device divides the materials into large-particle materials, medium-particle materials, small-particle materials and fine-powder materials according to the particle size; (3), the large-particle material return to the external circulating vertical mill and circulating grinding is carried out; (4), the small-particle materials and the fine-powder materials are sequentially subjected to two times of powder selection through a coarse powder selection machine and the fine powder selection machine; (5) the medium-particle materials are extruded in a roller press, then the medium-particle materials, small-particle materials and the fine-powder materials are sequentially subjected to two times of powder selection through the coarse powder selection machine and a fine powder selection machine; (6) fine powder screened by the coarse powder selection machine enters the fine powder selection machine, coarse powder rejected by the coarse powder selection machine and coarse powder rejected by the fine powder selection machine are converged and then return to the roller press and circularly extruding is carried out; and (7), the fine powder which meets the cement particle size are selected as a cement finished product through a fine powder selection machine. According to the cement grindingmethod, the particle size range of materials entering the roller press is reduced, large particles and fine powder do not exist so that roller gap fluctuation of the roller press can be reduced, thestability and the acting efficiency of the roller press are improved, the machine-hour yield is increased, the grinding power consumption is reduced, and meanwhile the cement performance is improved and optimized.

Description

technical field [0001] The invention relates to a cement grinding method. Background technique [0002] At present, there are two main methods of cement grinding, one is the combined grinding or semi-final grinding method composed of roller press and ball mill, and the other is the final grinding method of vertical mill with internal and external circulation (built-in powder separator); the first In the first method, because the shape of the powder after extrusion by the roller press is mainly needle-like and flake-like, the cement needs more water and the performance of the cement is not good; in addition, the cycle load is relatively large, generally around 700%, and the cycle The amount of fine powder in the extruded material is relatively large, and the particle size range of the material is large (particle size ranges from tens of microns to tens of millimeters), which leads to large fluctuations in the roll gap of the roller press, which in turn leads to greater vibrat...

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Problems solved by technology

[0002] At present, there are two main methods of cement grinding, one is the combined grinding or semi-final grinding method composed of roller press and ball mill, and the other is the final grinding method of vertical mill with internal and external circulation (built-in powder separator); the first In the first method, because the shape of the powder after extrusion by the roller press is mainly needle-like and flake-like, the cement needs more water and the performance of the cement is not good; in addition, the cycle load is relatively large, generally around 700%, and the cycle The amount of fine powder in the extruded material is relatively large, and the particle size range of the material is large (particle size ranges from tens of microns to tens of millimeters), which leads to large fluctuations in the roll gap of the roller press, which in turn leads to greater vibration and vibration of the roller press. The extrusion effect is not good, and in severe cases, water spraying is required to stabilize the material bed, but cement is different from cement raw meal powder, the performance of cement will be negatively affected after water spraying, and the strength of cement will decrease; the second method can adapt to the range of feed particle size For large materials, its adaptability to materials with large particle size is better than the first method, but compared with the first method, its energy consumption is relatively high, which needs further improvement

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