Recovery of cobalt from ammoniacal raffinate solution generated in processing of polymetallic sea nodules of Indian Ocean

Abstract

Batch and continuous scale adsorption studies of cobalt from the raffinate generated in reduction roast-ammonia leach-solvent extraction process of sea nodules have been investiagted where over 99% of cobalt has been adsorbed on lignite using sorbent/sorbate ratio 120 in 30 minutes. Desorption tests of cobalt from loaded lignite have also been carried out where over 99.5% of cobalt has been eluted in 0.5 molar sulphuric acid solution. The stripped lignite has been tested and found suitable for reuse. Cobalt of 99.9% purity has been achieved by electrolysis of the elute at current density 0.039 amp/cm2 having 75% current efficiency.