Abstract: With high lead,zinc and silver content reaching 58.31%, 22.79% and 352.90 g/t,respectively,the oxidized lead zinc ore in Yunnan is mainly constituted by hemimorphite and cerussite.In order to resolve problems brought by mixed lead and zinc during metallurgical process of this ore,froth floatation experiments have been performed to separate hemimorphite and cerussite in it and a new chelating-agent collector named C6403 has been employed in the experiments to improve floatation index.As the results show,a lead concentrate with lead grade of 42.04%, zinc grade of 9.63%,silver grade of 668.15 g/t,lead recovery of 83.22% and silver recovery of 66.23%, and a zinc concentrate with zinc grade of 43.51%, lead grade of 4.56%, silver grade of 183.30 g/t,zinc recovery of 89.36% and silver recovery of 33.77% were obtained by adopting the closed circuit process of three roughing,two cleaning,and middles back to the flow-sheet.Ultimately,both lead concentrate and zinc concentrate can meet requirements of smelting plants.

Key words: Oxidized lead-zinc ore, Hemimorphite, Cerussite, Separation of lead and zinc, Sulfurization, Chelating-agent collector C6403