Electrorefining Electrolyte from Copper Plant Dust

Abstract

An attempt was made to develop a suitable process for the recovery of copper from the dust sample of copper plant by sulphuric acid leaching with the idea that the resulting leached copper sulphate solution could be used directly as electrolyte in the copper electrorefining plant. XRD analysis of dust sample showed that copper was mainly present as sulphide and sulphate forms. Sulphuric acid leaching of the sample was carried out varying different parameters. The maximum copper recovery of 75% was achieved with the leaching parameters 353 K temperature, 4 h duration, 1:10 solid:liquid ratio and 10% H₂SO₄ concentration. Roasting followed by leaching experiments were also carried out. It was found that leaching of the roasted (873 K) sample in sulphuric acid medium yielded maximum copper recovery of 95%. Leaching kinetics of roasted product indicated that mixed control i.e. ash diffusion and chemical control reaction was prevalent. XRD analysis of the roasted sample showed that copper sulphide was converted to oxide which probably increased the recovery of copper. It was also found that composition of the leach liquor obtained in optimised condition was comparable with the composition of electrolyte of operating electrorefining plant.