Investigation of the effect of some polar organic solvents on the leaching and dissolution kinetics of chalcopyrite in hydrogen peroxide and sulfuric acid solution

Abstract

ABSTRACT. The effect of acetic acid and ethanol as polar aqueous solvents on sulfuric acid with hydrogen peroxide as an oxidant was studied. A small amount of these polar aqueous solvents significantly improved the copper leaching recovery. The leaching parameters such as temperature, stirring speed, H₂O₂ concentration, solid/liquid ratio, H₂SO₄ concentration and particle size were examined. About 76.33% as highest Cu extraction was gained with 2 M H₂O₂, 600 rpm stirring speed, 50 °C temperature, 1 M H₂SO₄, 240 min of the reaction and 75 x 53 µm particle size fraction. Further experimental tests were carried out when the stirring speed, solid-to-liquid ratio (S/L), particle size, H₂O₂ concentration, temperature and H₂SO₄ concentration were kept constant to investigate the effect of ethanol and acetic acid concentration in the range of 0–2 M. The experimental results proved that the copper extraction recovery reached to 99.03% in 180 min of the reaction with 2 M acetic acid. While 2 M of ethanol increased copper extraction recovery up to 100% in 90 min of the leaching time. The dissolution reaction found to be described by mixed kinetic model and activation energy of 54.37 kJ/mol. Addition of acetic acid and ethanol suggested reaction controlled by diffusion across product layer.

KEY WORDS: Hydrogen peroxide, Sulfuric acid, Activation energy, Leaching, Chalcopyrite

Bull. Chem. Soc. Ethiop. 2023, 37(3), 779-788.                                                            

DOI: https://dx.doi.org/10.4314/bcse.v37i3.19