Processing of copper dust for tolerable iron containing electrolyte

Abstract

Copper dust from the Indian Copper Complex, Ghatsila is water leached and the residue is subjected to leaching by sulphuric acid solution. Effects of various parameters on H₂SO₄ leachings of water leached residue (WLR) and as received copper dust have been investigated to obtain optimum conditions for leaching. Under optimum conditions, bulk leachings of WLR and as received copper dust by H₂SO₄ solutions have been carried out. Leaching of 150 g WLR by 1 dm³ of 15% (v/v) H₂SO₄ at 353 K for 4 h under reflux yields 1 dm³ leached solution containing 43·12, 16·20, 22·14, 0·40, 0·02, 0·04 and 0·12 g dm⁻³ Cu²⁺, Fe²⁺, Fe³⁺, Zn²⁺, Co²⁺, Ni²⁺ and Al³⁺ respectively, together with 0·90M unreacted H₂SO₄. Also, leaching of 160 g as received copper dust by 1 dm³ of 10% (v/v) H₂SO₄ at 353 K for 4 h under reflux yields a leach solution containing 44·30, 9·00, 15·70, 0·40, 0·15, 0·03 and 0·11 g dm⁻³ Cu²⁺, Fe²⁺, Fe³⁺, Zn²⁺, Co²⁺, Ni²⁺ and Al³⁺ respectively, together with 0·90M free H₂SO₄. The iron contents of these solutions have been reduced to the levels of <0·5 g dm⁻³ by applying D2EHPA extraction–oxalic acid stripping technique so that the solutions can be used as electrolytes in electrorefining, electrowinning or hydrogen reduction of copper.