Recovery of nickel from the ammoniacal solution of chromite ore overburden by solvent extraction-electrowinning

By the reduction roast-ammonia leach process, an unexploited oxidic resource viz., overburden of chromite ore mines of Orissa, India, was treated to solubilise nickel and cobalt metals. For the separation and recovery of nickel and cobalt from this solution, application of LIX84-an oxime based solvent has been explored with the aim of producing electrolytic nickel metal. The bench scale experiments were initially carried out in a kinetic vessel metal. The bench scale experiments were initially carried out in a kinetic vessel for the extraction and stripping etc. were optimised. Based on these actual leach solutions containing 5.0g/L Ni and 0.077 g/L Co. These experiments showed the feasibility of extracting nickel with 30% LIX84 in kerosene in three stages and stripping of the loaded nickel with electrolyte solution at pH in four stages. The nickel pregnant electrolyte obtained from the solvent extraction at pH 1.1 in four stages. The nickel pregnant electrolyte obtained from the solvent extraction (SX) stage was found suitable for producing metal by electrowinning (EW) in the closed-loop SX-EW operation. At 50 C the average energy consumption and current efficiency were found to be 4.54kWh/kg and 69.0% respectively. Results show the possibility of producing electrolytic nickel metal from the overburden material by roast-leach-SX-EW route.