针对大坪选厂细磨工段磨矿产品粒度均匀性差，磨矿细度-0.074 mm含量不达标，过粉碎含量偏高等问题，制定了磨矿介质制度优化方案，通过实验室磨矿试验得出细磨工段磨矿介质采用钢段效果更佳，其磨矿介质制度：Φ45×50∶Φ35×40∶Φ30×35∶Φ25×30=30∶20∶20∶30。试验结果表明：全面钢段方案与钢球方案及现厂方案相比，各项指标均得到一定的提高，过粗级别+0.10 mm产率分别减少了0.73个百分点和5.42个百分点，过粉碎级别-0.010 mm产率分别减少了2.51个百分点和0.77个百分点，磨矿细度-0.074 mm含量分别提高了1.75个百分点和5.33个百分点，中间易选级别0.100~0.038 mm产率分别提高了1.96个百分点和5.57个百分点，磨矿技术效率分别提高了3.54个百分点和8.14个百分点，磨机-0.074 mm利用系数分别提高了3.15%和10.24%。因此，根据试验前后各项指标对比，全面钢段更加适用于细磨工艺，能够有效改善“两端多、中间少”的现象，提高磨矿效率和合格产品质量占比。

The particle size of the grinding products in the fine grinding section of a domestic mineral processing plant is uneven，and there are more coarse-grained and over-fine-grained grades.At the same time，the content of the grinding fineness -0.074 mm does not meet the standard.According to the current mill grinding process，combined with the nature of the ore itself in the concentrator，the grinding quality is improved through the grinding process.This paper uses the international standard sieve for particle size screening of the ore sampled uniformly，combined with the spherical diameter semi-theoretical formula to formulate the grinding plan，compare the grinding results，evaluate and select the best grinding plan.Laboratory test results and data analysis show that the grinding media system is Φ45×50∶Φ35×40∶Φ30×35∶Φ25×30=30∶20∶20∶30. Compared with the steel ball plan and the current plant plan，the overall steel section plan has an over-coarse level of 0.10 mm and a yield reduction of 0.73 percentage points and 5.42 percentage points，respectively，and an over-pulverization level of 0.010 mm and a yield reduction of 2.51 percentage points and 0.77 percentage points，respectively.The grinding fineness -0.074 mm content has increased by 1.75 percentage points and 5.33 percentage points respectively.The intermediate easy-selection grade 0.100~0.038 mm yield has increased by 1.96 percentage points and 5.57 percentage points，respectively，and the grinding technology efficiency has been improved by 3.54 percentage points and 8.14 percentage points，mill q_-200 increased by 3.15% and 10.24%.According to the comparison of various grinding indexes，it can be concluded that the grinding method of the steel section in the grinding process is mainly based on the grinding and peeling effect，supplemented by the impact effect，which can effectively reduce the content of coarse-grained and super-fine-grained grades，and improve the qualified grain.The level of content reduces the difficulty of flotation.The increase of the efficiency of grinding technology shows the improvement of the quality of grinding products，and the increase of the mill q_-200 shows the improvement of the production capacity of the mill’s unit effective volume.The above conclusions indicate that the steel segment is more suitable for fine grinding process，it improve the quality of grinding products，the production capacity of the mill and the efficiency of the enterprise.