Recovery of nickel and cobalt from leach solutions of nickel laterites using a synergistic system consisting of Versatic 10 and Acorga CLX 50

• A synergistic system consisting of Versatic 10 and CLX 50 was studied for nickel and cobalt recovery.
• Semi-continuous tests were employed to evaluate the efficiency of the synergistic system.
• The synergistic system is effective to recover nickel and cobalt and separate from manganese, calcium and magnesium.

A direct solvent extraction (DSX) process to recover nickel and cobalt from laterite leach solutions is potentially more cost effective compared to the traditional precipitation and re-leaching method. A synergistic solvent extraction (SSX) system consisting of Versatic 10 and Acorga CLX 50 in ShellSol 2046 was studied for DSX nickel and cobalt recovery from a synthetic solution using semi-continuous tests. The effect of pH on the metal distribution profile and metal separation were investigated. It was found that the SSX system can effectively recover nickel and cobalt and separate them from manganese, calcium and magnesium. Over 99% of Ni and Co was extracted using four stages of semi-continuous extraction from the synthetic laterite solution at pH 6.3 and an A/O flowrate ratio of 1:1. More than 80% of the manganese was rejected to the raffinate. The co-extraction of calcium was less than 5% and the co-extraction of magnesium was negligible under these conditions. The co-extracted manganese and calcium were readily scrubbed in three stages semi-continuous scrubbing. The loaded strip liquor with a high concentration of nickel (71.3 g/L Ni) was obtained after two-stage continuous stripping. The final strip solution pH of 3 would be suitable for nickel electrowinning. A conceptual DSX process flowsheet using the SSX system to recover nickel and cobalt from laterite leach solutions after iron removal has been proposed.