Solvent Extraction Separation of Co(II) from Synthetic Leaching Sulfate Solution of Nickel Laterite Ore with High Magnesium Content

Leaching of nickel garnierite ore with sulfuric acid resulted in a mixed sulfate solution of Co(II) and Ni(II) with high magnesium content. In order to find an optimum condition to separate cobalt, solvent extraction experiments have been performed from the synthetic leaching sulfate solution with the following composition: Co(II) = 0.08 g/L, Ni(II) = 4.4 g/L, Mg(II) = 32.2 g/L. The effects of extraction variables on the separation of Co(II) from nickel and magnesium were investigated by using D2EHPA, PC88A, Cyanex272, and Alamine336. Saponifiaction degree of cationic extractants, extractant concentration, and volume ratio were changed. In our experimental range, extraction of nickel was negligible. Among the cationic extractants tested in this study, the highest separation factor between Co(II) and Mg(II) was obtained with saponified Cyanex272. Alamine336 in the presence of MgCl2 extracted only Co(II), while the extraction percentage of Mg(II) was nearly zero. [doi:10.2320/matertrans.M2011027]