Recovery of Co(II) and Ni(II) from chloride leach solution of nickel laterite ore by solvent extraction with a mixture of Cyanex 301 and TBP

Cyanex 301 can extract both Ni(II) and Co(II) from the leach solution of nickel laterite ore. About 10 mol/L HCl solution is needed to strip Ni(II) from the loaded Cyanex 301. To overcome this difficulty, a mixture of Cyanex 301 with TBP was employed to develop a process for the recovery of Co(II) and Ni(II) from the laterite leach liquor. It was found that this mixture showed synergism on the extraction of Ni(II) and significant improvement in Ni(II) stripping was obtained. A developed process was proposed, in which Co(II) and Ni(II) were selectively extracted by this mixture over other elements, and then stripped with 3 and 7 mol/L HCl solutions, respectively. A comparison of single Cyanex 301 and Cyanex 301 + TBP process was made and discussed in detail. The essential advantages of single Cyanex 301 process were retained in this mixture process, while the main drawback in Ni(II) stripping was improved. Batch-type experiments were conducted to simulate multi-stage counter-current extraction and stripping, indicating that Ni(II) of 99.96% purity was obtained with a recovery percentage of 92.7%.