Cobalt-nickel pertraction refinery to process pregnant leach solution from recycled spent catalysts. Part 1: Cobalt extraction from a binary system

Abstract

Owing to the recent increase in the global demand for Co, new cobalt-nickel refinery capacity is required. While solvent extraction is one of the most important separation and purification techniques in hydrometallurgy, pertraction, also called membrane-based solvent extraction, offers various advantages over conventional solvent extraction. In this study, pertraction was used to purify a pregnant leach solution obtained from spent hydrotreatment catalysts that had been produced by Minemet. A block flow diagram and mass balance for the cobalt-nickel refinery were developed and used in the experimental design. Extraction isotherms were determined as well as mass transfers optimised using a circulating batch pertraction setup for both synthetic and industrial cobalt-nickel mixed metal solutions. A comprehensive set of models was applied to translate the experimental data into a conceptual design of the industrial cobalt-nickel pertraction refinery to process pregnant leach solution from the Minemet plant