Possibility of Environment-Friendly Hydrometallurgical Treatment of Copper-Zinc Concentrate Containing Arsenic

Abstract

Pyrometallurgical treatment of copper concentrates containing arsenic poses a problem due to the emission of toxic gaseous arsenic oxides. Therefore, the development of effective environment-friendly hydrometallurgical approaches allowing extracting metals from these concentrates without gas emission is a relevant issue. The goal of the present work was to study the effect of chloride on the bioleaching of Cu-Zn concentrate containing tennantite and solid residue of its alkaline sulfide leaching (ASL) in order to evaluate the possibility to improve bioleaching of Cu-Zn concentrates containing tennantite using ASL pretreatment and NaCl addition. In NaCl absence, bioleaching of the concentrate made it possible to extract 52 and 62% of Cu and Zn for 30 days. The addition of 100 mM NaCl allowed extracting 66 and 93% of Cu and Zn. In the same time, bioleaching of ASL residue made it possible to extract 74 and 66% of Cu and Zn, while NaCl addition to the medium inhibited Cu and Zn extraction during ASL bioleaching and 35 and 62% of Cu and Zn were leached. Thus, it was shown, that both ASL pretreatment and NaCl addition increased the rate of copper and zinc bioleaching from the concentrate, while NaCl addition to the medium led to inhibition of ASL residue bioleaching. Therefore, both methods can be considered as promising approaches to increase metal extraction from Cu-Zn concentrates containing tennantite but the effect of each factor should be studied in detail to develop effective technologies.