CHARACTERISTICS OF THE ROASTING PROCESS OF COPPER-ZINC-LEAD SULFIDE CONCENTRATE

Abstract

The features of the roasting process for a unified copper-zinc-lead sulfide concentrate are presented. In the produced unified copper-zinc-lead sulfide concentrates, copper exists in the form of chalcopyrite (CuFeS2), zinc in the form of sphalerite (ZnS), and lead in the form of galena (PbS). These concentrates are characterized by a high iron content, where iron is present in the form of pyrite (FeS2) and occasionally pyrrhotite (FeS). The concentrates also contain certain amounts of precious metals, primarily gold and silver. In addition to the main components-copper, zinc, and lead-the concentrate contains a significant amount of iron and is notable for its specific gold and silver content.

The goal of the roasting process is to ensure the transition of the main metals in the unified sulfide concentrate into the roasted material and to create favorable conditions for the subsequent dissolution of the roasted product, enabling the extraction of copper, lead, zinc, iron, and the subsequent convenient separation of gold and silver. Thermodynamic analysis has substantiated the probability of the main reactions occurring during the roasting of the unified sulfide concentrate.

It has been shown that for the efficient extraction of these metals, low-temperature sulfate roasting of the unified sulfide concentrate is preferred. During this process, the primary metallic components in the sulfide form are converted into their sulfate compounds, which allows the sulfate-containing roasted product to undergo dissolution and further processing stages to extract the specified components.

The optimal temperature for the sulfate roasting of the unified copper-zinc-lead sulfide concentrate has been determined to be 570°C. At this temperature, the resulting sulfate-containing roasted material, with its main components (CuSO4, FeSO4, Fe2(SO4)3, ZnSO4, PbSO4), is largely soluble in weak aqueous solutions of sulfuric acid, facilitating the extraction of the mentioned metals without significant challenges.