Abstract: In order to improve the grinding and classification efficiency of a refractory molybdenite ore in Henan Province, and solve the problem that the content of -0.075 mm particle size in the old series grinding system is often lower than 60% and the coarse particle loss in tailings due to high oxidation, high viscosity and easy mudding of the ore, the secondary classification transformation is carried out.After the overflow of the old series of grinding classification, a cyclone is added for secondary classification to ensure that the fineness of the feed reaches the standard, and the cyclone grit is sent to the new system mill for re‐ grinding. The concentration of the old series of ore slurry is adjusted synchronously, and the concentration of the original ore slurry is increased from 28.37% to 40%～45%, so that the fineness of the system is sta‐ bilized at 48%～50%.The industrial test results after the transformation show that the overall fineness of the grinding classification system meets the production requirements, and the actual total processing capac‐ ity of the system is increased by 2.15%. The grinding classification effect is effectively optimized, and the problem of coarse particle loss in tailings is solved.Increasing the concentration of the old series of pulp is helpful to stabilize the grinding fineness, optimize the grinding classification process, provide an effective path for the process transformation, and provide a reference for the optimization of the grinding classifica‐ tion system of similar refractory molybdenum ore. It has certain engineering application value and can im‐ prove the production efficiency and economic benefits of the concentrator to a certain extent.

Key words: refractory molybdenite, grinding classification, process transformation