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.
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