SYNTHESIS OF COPPER METAL/SALTS FROM COPPER BLEED SOLUTION OF A COPPER PLANT

Copper bleed solution (CBS) generated during the electrorefining of anode copper contains 40 g/L Cu, 10–20 g/L Ni, and 170–200 g/L H₂SO₄, along with other impurities in different quantities. In order to get the valuable metals from this CBS, studies have been carried out to crystallize and recover metal salts on bench scale with/without partial decopperization from the point of view of reuse and the recycling of the sulphate salts and the acid recovered back to the system. Studies showed the possibility of recovering copper sulphate salt without affecting its purity with respect to nickel by controlling the extent of evaporation. In an alternative approach, a part of copper metal of purity 99.85% produced during partial decopperization of copper from 39.8 to 9.64 g/L Cu without affecting the current efficiency at a current density of 100 A/m². Subsequently, mixed salt containing 9.80% Cu and 13.19% Ni has also been produced from the partially decopperized solution. The mixed salt could be processed for metal recovery by solvent extraction. The mother and wash liquor could be recycled in the electrorefining plant for acid and copper make-up.

Keywords:

• copper bleed solution (CBS)
• copper sulphate
• crystallization
• mixed sulphate

ACKNOWLEDGMENT

The authors are thankful to the Director, National Metallurgical Laboratory, Jamshedpur, India, for his kind permission to publish this work.

Notes

∗A: Crystal wt.g, ∗B: mother liquor (ML) + wash liquor (WL) mL.

Copper bleed solution (CBS): 600 ml, chemical analysis Cu: 23.05, Ni: 11.62, H₂SO₄: 102.9, Fe: 0.452, Bi : 0.12, Sb: .033.

Conditions of crystallization: V = 0.6 L, temp. = 100 ± 5°C, % Evaporation: 33.

∗A: Crystal wt.g, ∗B: mother liquor (ML) + wash liquor (WL) mL.

Copper bleed solution (CBS): 600 ml, Cu: 23.92, Ni: 5.75, H₂SO₄: 116.42, Fe: 0.153, Bi: 0.065, Sb: .033.

Synthetic CBS (g/L): 38.42 Cu, 19.37 Ni, 0.755 Fe, 0.20 Bi, 171.5 H₂SO₄.

CBS from ICC Ghatsila (g/L): 39.86 Cu, 9.58 Ni, 0.255 Fe, 0.108 Bi, 0.0007 As, 0.055.

Sb, 194.0 H₂SO₄.

Volume of the CBS: 1L.

Cathode: Titanium, Anode: Lead-6% Antimony.

Current density: 100 A/m².

Conditions of crystallization: V = 0.99 L, temp = 100 ± 5°C, % Evaporation: 80