Flotation of Oxidized and Complex Lead-Zinc Ores: Research and Practice

摘要

Large deposits of mixed and oxidized lead-zinc ores occur in southwest and northwest China. The mineralogical composition of these ores is complex, owing to deep weathering, the presence of slimes and ferruginous material, fine intergrowths and the high degree of oxidation. The new flotation method that has been applied successfully at the Chaihe lead and zinc concentrator includes careful multistage grinding to minimize the generation of secondary slime while securing optimal liberation of the valuable constituents; the application of two-stage selective flotation (differential flotation of lead and zinc sulphides followed by differential flotation of the lead and zinc oxides); the use of an effective collector for lead oxides, such as cyclohexane-ammonium dithiophosphate, in the sulphidization flotation process of the lead oxides; and a new method of zinc oxide flotation without desliming with an amine-type collector emulsified in sodium sulphide solution combined with effective depressants, such as sodium hexametaphosphate and sodium silicate. By this new flotation method overall recovery is increased by more than 20% and that of zinc oxides by 20-25% in comparison with the conventional method.