Production of high purity magnetic nickel powder from spent DRI catalyst via cementation method

•A two step method was developed to produce high purity Ni from spent DRI catalyst.•Complete Ni extraction with negligible Al dissolution could be achieved by HCl leaching.•Quadratic models were generated to predict Ni recovery and undesired Al dissolution.•Ni cementation by Al powder was investigated thoroughly using optimal leached liquor.•The optimal cementation condition for higher Ni efficiency and purity were introduced.