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Abstract

A process is provided for the selective recovery from an impure solution of pure nickel and cobalt solutions, suitable for electrolysis of the respective metals. The impure solution may be that obtained from acid leaching of nickel/cobalt bearing laterite or oxide ore. The impure solution is contacted with a solid ion exchange resin to selectively extract nickel and cobalt, while rejecting at least one element of the group manganese, magnesium, calcium, iron(II), and chromium(III). The ion exchange resin contains bis-picolyl amine as the primary chelating group. The impure solution has sufficiently low levels of chromium(VI) and copper to allow repeated use of the ion exchange resin. The metal-bearing resin is washed and then stripped with an acid solution. This solution is then contacted with a water-immiscible organic phase for the selective extraction of cobalt, leaving nickel in the raffinate as a substantially pure nickel solution. The loaded organic phase is stripped with another acid solution to produce a substantially pure cobalt solution. The extractant contains an organic phosphinic acid as the active group for extraction. Nickel and cobalt can be recovered in essentially pure form from the respective pure nickel and cobalt solutions by a variety of conventional techniques, for example by electrowinning.

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