Abstract: Baixiangshan concentrator reforms the second-stage grinding，and changes the ball mill of the second-stage grinding equipment into a tower mill to improve the grinding index and stabilize the quality of iron concentrate.In order to analyze and compare the effect of the transformation，the beneficia⁃ tion process of the roller mill + grinding and beneficiation system in Baixiangshan Concentrator is investi⁃ gated before and after the transformation，and the operating conditions of each operation and each process are comprehensively analyzed and evaluated.The results show that it is reasonable to replace the ball mill with the tower mill in the second stage grinding. After the transformation，the processing capacity of the plant is 327.57 t/h，the iron concentrate grade of the production index is 64.82%，and the iron recovery rate is 80.35%，which achieves the expected effect of technical transformation.

Key words: process investigation, grinding and classification, magnetic separation, high frequency fine sieve, tower mill