Electrowinning of cobalt from sulphate solutions

This paper reports an account of study conducted on optimization of the process parameters for electro-winning of cobalt from cobalt sulphate solution. Effect of parameters such as bath composition, temperature, current density, agitation etc. on the voltage requirement, current efficiency and power efficiency of cobalt electro-deposition was explored. A maximum current efficiency of 97% was attained with an electrolyte composition of 60 g/L Co, 15 g/L Na2SO4, at a temperature of 60 °C, a pH of 4.0 and a cathode current density of 400 A/m2. The energy consumption was 3.0 kWh/kg of Co deposited. The optimum conditions so established were test examined for recovery of cobalt values from leach liquors generated on processing of Alnico magnet scrap, cemented carbide tool scrap and spent hydrogenation catalyst. The cathode current efficiency ranged from 86% to 94% due to lower concentration (25 to 40 g/L) of cobalt concentration in the processed leach liquor.