Separation and recovery of cobalt and nickel from end of life products via solvent extraction technique: A review

The significant development in advanced technologies such as lithium-ion batteries has increased the demand of cobalt and nickel. As a result, continuous supply from primary resources leads cobalt to the critical stage and also affects nickel resources extensively. The presence of limited resources can lead to break in the chain of supply of these metals on demand. Therefore, it is necessary to recycle cobalt and nickel from secondary resources in order to continue the chain of demand and supply. This review provides a detail on solvent extraction processes developed for the separation and recovery of cobalt and nickel from secondary resources in the last decade. The study illustrates applicability of different type of extractants to provide better separation and recovery of said metals from potential wastes originated from different sources. The fundamentals of solvent extraction along with mechanisms of different class of extractants involved in the recycling of metals have been discussed in detail. •SX processes for Co and Ni recovery from spent matrices are reviewed.•The applicability and potential of ionic liquids in SX is reported.•Research gap between academic research and larger scale operations is identified.•Need of a greener and cost-effective process is recommended.