Recovery of nickel and cobalt from acid leach pulp by ion exchange using chelating resin

Sorption processes, especially sorption from pulps, are of considerable interest in nickel hydrometallurgy. The use of polymeric resins in pulp process allows elimination of expensive and extensive operations of filtration or countercurrent decantation from the flowsheet. The preliminary comparison of capital and operating costs indicates that resin in pulp process can compete successfully with liquid-liquid extraction and precipitation processes and may be considered as a feasible alternative when designing nickel hydrometallurgical plants. Based on this approach, resin in pulp batch tests were carried out to evaluate the nickel adsorption characteristics. An iminodiacetic acid polymeric resin was selected for nickel adsorption from sulfate acidic solutions. The results showed that the resin was able to provide nickel and cobalt extractions from solution greater than 99% after five counter-current stages. It was also observed that nickel and cobalt could be extracted from solids in the pulp due to “sorption leach” phenomena. The resin process continuously removed nickel and cobalt from the solution allowing the potential for further solids leaching. A maximum load resin capacity of 100 g Ni/kg was obtained in these tests.