HYDROMETALLURGICAL PROCESSING OF CHALCOPYRITE CONCENTRATES FOR COPPER, GOLD, AND SILVER RECOVERY

Abstract

The present work describes the specific features of hydrometallurgical processing of copper concentrates. The characteristics of heap leaching, in-situ (vat) leaching, and bioleaching processes are presented. In industrial copper concentrates, copper is predominantly present in the form of chalcopyrite (CuFeS₂) and chalcocite (Cu₂S), while iron occurs mainly as pyrite (FeS₂). The optimal technological conditions for concentrate leaching have been outlined with the aim of achieving maximum recovery of valuable metals. It is demonstrated that the selection of an appropriate processing scheme must be based on the mineralogical composition of the feed, the distribution of the associated metal phases, and the concentration of recoverable components.

            For sulfur-rich copper concentrates, direct chloride leaching is identified as the most efficient method, characterized by high copper dissolution rates, strong selectivity, and favorable operating conditions. Under optimized parameters, copper fully transitions into solution in the form of monovalent copper chloride, which is subsequently processed to obtain high-purity metallic copper.

            Iron recovery from the insoluble oxide residues is carried out through a controlled two-stage hydrogen reduction process, resulting in metallic iron powder suitable for industrial applications. The final oxide tailings, enriched with gold and silver, undergo cyanide leaching followed by precipitation and electrochemical treatment to produce a high-quality doré alloy.

            The proposed integrated technological scheme ensures comprehensive utilization of the feedstock and high recovery efficiencies for both base and precious metals. Moreover, the closed-cycle nature of chloride leaching and the reduction of secondary waste enhance the environmental safety and overall sustainability of the process.