Abstract: In order to solve the problems of low recovery efficiency of valuable metals and high risk of separation pollution in a high-sulfur low-grade copper-lead-zinc polymetallic sulfide ore in southwest China，a systematic process mineralogy test is carried out for its low grade of valuable metals，high pyrite content，fine mineral dissemination，serious flotation interference and difficult separation. The mineral composition，dissemination symbiosis characteristics and monomer dissociation law of the ore are identi⁃ fied，and the internal mechanism of the ore is revealed.Through the condition optimization test，a clean separation process of cyanide-free copper lead mixed flotation-copper lead separation-zinc flotation-sulfur comprehensive recovery is constructed. The green collector and cyanide-free composite inhibitor are used to realize the efficient separation of multi-metals and the comprehensive recovery of associated gold，silver and cadmium.The results show that the lead concentrate with lead grade of 56.24% and lead recovery of 89.58%，the copper concentrate with copper grade of 18.62% and copper recovery of 90.14%，the zinc concentrate with zinc grade of 48.26% and zinc recovery of 89.09%，and the sulfur concentrate with sulfur grade of 44.22% and sulfur recovery of 66.71% are obtained by the whole process closed-circuit test. The associated precious metals and scattered metals are enriched and recovered simultaneously.The cyanide�free green separation process has excellent separation index，which can provide theoretical basis and engi⁃ neering technical reference for the green and scaled development of similar complex polymetallic ores in Southwest China.

Key words: high-sulfur-low grade ore, copper-lead-zinc polymetallic sulfide ore, process mineralo? gy, cyanide free flotation, separation mechanism