China Nonferrous Metallurgy

As the main material for electrolytic refining of nickel, the nickel sulfide concentrate contains massive impurities, e.g., iron, copper, cobalt, lead, zinc. Among these, iron is one of the major impurities during the electrolytic refining of nickel. Currently, the electrolytic refining of nickel sulfide mainly involves two systems, soluble-anode electrolysis and insoluble-anode electrodeposition, which produce electrolytic nickel and electrodeposited nickel respectively. To prevent impurity precipitation at the cathode, which will affect the quality of electrolytic nickel, it is necessary to reduce the iron content in the solution. In this paper, the thermodynamics of iron removal precipitation of electrolytic refining of nickel is discussed, also discussed are four major iron removal technologies used in the hydrometallurgy production of nickel, namely, neutralization hydrolysis process, sodium jarosite process, hematite process and goethite process. In addition, the existing problems in the industrial application of iron removal technologies in the purification process of the electrolytic refining of nickel system and in the leaching process of the nickel electrodeposition system, together with the advantages and disadvantages of the four iron removal methods were analyzed. A prospect about the iron removal technology based on the magnetofluid-assisted chemical precipitation method was also provided.