Pressure oxidative leaching of copper concentrate Scientific paper

Abstract

This study investigated the oxidative leaching of copper concentrate using a mixture of ferric ions and sulfuric acid solutions. We examined the effects of various parameters, including temperature, initial sulfuric acid con­centration and slurry filtration conditions. At lower temperatures (150 °C), the leaching process resulted in the elemental sulfur and jarosite minerals formed in the solid residue. In contrast, at higher temperatures (190 °C), the solid resi­due contained jarosite and hematite, the most elemental sulfur-oxidizing to sul­furic acid. Under optimal conditions, a leaching temperature of 190 °C, a con­centrate-to-leaching solvent (Fe³⁺ 5 g L^-1 and H₂SO₄ 50 g L^-1) ratio of 1:8, an oxygen pressure of 1.0 MPa, and a solid phase particle size of less than 20 μm the dissolution rate of copper reached 98 % after 3 h. When the sulfuric acid concentration increased from 30 to 100 g L-1, the amount of copper increased from 40 to 48 g L^-1. Furthermore, rapid filtering of the leaching solution with­out cooling helped retain most of the iron in the solid phase, resulting in a relatively pure solution. The solid residue was analyzed using X-ray diffraction and scanning electron microscopy.