Low-grade nickelliferous laterites are important sources of nickel and cobalt, since80% of the world’s known reserves of nickel are associated with such types of deposits.Nickel can be produced by pyrometallurgical and hydrometallurgical routes. However, forthe lower-grade lateritic ores, hydrometallurgical treatment seems to be favourable for the simultaneous recovery of nickel and cobalt, as far as plant economics and environmental aspects are concerned [1,2].Sulphuric acid heap leaching, at ambient temperature, of a low-grade limonitic lateriteGreek ore has been reported [3,4]. Despite the efficient extraction of nickel and cobalt,contamination of the pregnant leach solution with impurities is unavoidable. A typicalchemical composition of leach liquors is given (table I). This shows that a significant amountof dissolved Fe, as well as other impurities such as Al, Cr, Mg, Na and K, are present insolution along with Ni and Co. Thus, before the electro-extraction of these metals, a priorsolution purification step is required.
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