The development of a hydrometallurgical hydrochloric acid-based leaching process for the treatment of nickeliferous laterites of various types is described. A key step is the separation and concentration of the nickel in the leach liquor (1-5 g/L) from magnesium and/or iron to a tenor compatible with electrowinning or hydrogen pressure reduction. This can be achieved using solvent extraction with Cyanex 301, Cyanex 302 or with Versatic 10, which displayed the best extraction characteristics. Cyanex 301 showed excellent selectivity for Ni but was very difficult to strip, except with high concentrations of acid. Cyanex 302 seemed suitable but co-extraction of magnesium was appreciable.
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