As and Sb leaching from polymetallic sulfide concentrates

The leachability of antimony and arsenic from Peruvian complex sulfide conc entrates (Casapalca, Huaron) were studied by alkaline Na2S leaching. The ex periments have shown that by a proper mechanical activation of the difficul t to treat concentrates 99% Sb and 99% As from Casapalca and 63% Sb and 80% As from Huaron can be eliminated. The chemical composition of CuPbZnAg con centrates after Sb and As elimination may improve the further pyrometallurg ical treatment from the technological as well as environmental aspects.