Solid state reduction and magnetic separation of nickeliferous laterite ores: Review and analysis

Abstract

As the global demand for nickel transitions from ferronickel to nickel sulfate for batteries, the nickel sulfide ore reserves are becoming increasingly more difficult to mine. Although, the mining of the nickeliferous laterite ores is much simpler, the extraction of the metal is more challenging, with limited process options. Furthermore, the current processing techniques are costly and have environmental issues, resulting in the need to develop alternative technologies through laboratory research and pilot plant testing. In this paper, firstly, an overview is provided of the composition plus mineralogy of both the limonitic and the saprolitic nickeliferous laterite ores and of the current commercial techniques that are employed to process these ores. Secondly, the pyrometallurgical research work reported in the literature on the production of a nickel concentrate by selective reduction followed by magnetic separation is reviewed. The main objectives are to achieve a high nickel recovery and to produce a concentrate with a high nickel grade. Thirdly, the role of additives, in particular the sulfur-containing species, is evaluated. Fourthly, the main issues involved in the processing of these ores and of particular importance, the areas that require further research and development are discussed. Finally, the potential of these new developing processes to replace the current commercial operations is assessed.