Abstract:A low-grade lead-zinc sulfur ore in Yunnan uses a section of abrasive process process of "priority flotal leading lead -lead tail mine flotation zinc". It has a long -term problem of zinc concentrate containing SIO2 higher than 10%, which seriously affects the economic benefits of the concentrating mill.In order to solve this problem, based on the process mineralogy of ore, the process mineralogy of high-silicon zinc concentrate produced in the field process was studied, and the process optimization test was carried out.The MLA analysis results show that the main reason for the high SiO2 content of zinc concentrate is that +0.074mm quartz and sphalerite associated biota enters zinc concentrate, and fine grinding is required to further improve the monomer dissociation of quartz and sphalerite.In this study, the "stage grinding and stage sorting" process of re-grinding and re-sorting of coarse zinc concentrate was proposed to optimize the process.The optimized flotation closed-circuit test obtained lead concentrate with Pb grade of 55.23% and Pb recovery of 80.79%, zinc concentrate with Zn grade of 54.11% and Zn recovery of 83.48%, SiO2 grade of 4.36% and SiO2 recovery of 0.43%.Compared with the flotation indexes of the on-site process before optimization, the Pb grade and recovery of lead concentrate changed very little, but the Zn grade of zinc concentrate increased by 3.20 percentage points, and the SiO2 of zinc concentrate decreased by 6.20 percentage points, which had a significant effect of improving quality and reducing silicon.The results of this study provide an important technical support to improve the economic efficiency of the dressing plant.