Effect of Sulfuric Acid Concentration on Marmatite Dissolution in the Presence of Cupric Ions

Abstract

Marmatite often associates with copper sulfide ore with the role of Cu2+ in marmatite dissolution being important in hydrometallurgy. In this work, we found that cupric ions (Cu2) can accelerate marmatite dissolution significantly at high temperature, regardless of sulfuric acid concentration (pH 0.5–2.5). Marmatite dissolved faster at lower acid concentrations and compared with cupric-free conditions, and the concentration of zinc dissolved in the presence of Cu2+ ions increased by 5500 mg/L. When the acid concentration was high (pH above 2.5), the acceleration effect of high Cu2+ concentration was more obvious. In addition, the consumption of Cu2+ was low at high acid concentration (pH below 1.5), but Cu2+ consumption increased significantly at low acid concentration (pH above 2.5). X-ray diffraction (XRD) of the leaching residues proved that no copper-containing mineralogical phase was produced at high acid concentration, but copper-containing products were formed at low acid concentration. Kinetic analysis showed that marmatite dissolution was mainly controlled by surface reaction. The reaction between Cu2+ and marmatite should be different at different concentrations of sulfuric acid.