Abstract: For many years,Huangshaping leadzinc concentrator has adopted the preferential flotation process of leadzinc under the condition of high alkalinity to recover leadzinc.The addition of a large amount of lime has restrained some of the lead and silver metallic minerals,which leads to the difficulty in breaking 45% of the recovery of associated silver with lead concentrate.There are some environmental problems such as high alkalinity and COD of tailings water in concentrator.In order to improve the recovery rate of associated silver and improve the environmental protection level of Huangshaping,the company organized and carried out the research on the new mineral processing technology of leadzinc limefree production.The results show that under the condition of natural pH,the recovery of lead and zinc is increased by 0.3 percentage points and the recovery of zinc is increased by 1.5 percentage points compared with the highalkali process The recovery of associated silver in lead concentrate was increased by 9.82 percentage points,and the economic and environmental benefits were significant.

Key words: Alkalifree beneficiation,Clean production,Flotation,Associated silver,Recovery,Environmental protection,COD