Recovery of nickel from spent NiO/Al2O3 catalyst through sulfuric acid leaching, precipitation and solvent extraction

Effective recovery of nickel (Ni) from spent NiO/Al2O3 catalyst in a simple hydrometallurgical route is suggested. Nickel recovery of 99.5% was achieved with sulfuric acid leaching. The leach liquor was partly neutralized and nickel ammonium sulfate was precipitated by adding ammonia. The nickel in the supernatant was concentrated by solvent extraction using D2EHPA and subsequently stripped back into sulfuric acid and returned to the precipitation stage. Necessary counter current extraction and stripping stages were determined in McCabe–Thiele diagrams. The suggested method appears simple and very effective in recovering nickel from spent catalysts from the petrochemical industry