Abstract: A process is provided for the leaching of both the “limonite” (Fe approx. ≧25% and Mg approx. ≧6%) and “saprolite” (Fe approx. ≦20% and Mg approx. ≧10%) fractions of typical nickel and cobalt bearing laterite ore. The low magnesium fraction of the laterite ore is leached with sulfuric acid at high pressure and temperature to solubilize the metal values while precipitating most of the solubilized iron as hematite or other iron compounds and a portion of the dissolved aluminum as alunite or other aluminum compounds. After reducing the pressure of the leach slurry to approximately atmospheric pressure, the pregnant leach slurry or solution is contacted with the high magnesium fraction of the ore to solubilize most of the nickel contained in the high-magnesium ore fraction while dissolving only a small portion of the iron content of the high magnesium ore fraction.

Abstract: A process is provided for the direct recovery of nickel and cobalt from a nickeliferous oxide ore leach slurry by ion exchange. A nickeliferous ore is leached with mineral acid to solubilize the metals. The resulting leach slurry is contacted with ion exchange resin, which selectively loads the nickel and cobalt from the pulp. The resin is separated from the leach slurry by screening and then stripped with an acidic solution. After stripping, the resin is returned to the loading cycle. Nickel and/or cobalt can be recovered in substantially pure form from the eluate by known processes. The metal-depleted slurry proceeds to waste treatment and disposal. This process eliminates the difficult solid/liquid separation, which would otherwise be required to recover metals values from the pregnant leach slurry.

Abstract: A process is provided for the leaching of both the “limonite” (Fe approx. ≧25% and Mg approx. ≦6%) and “saprolite” (Fe approx. <20% and Mg approx. ≧10%) fractions of typical nickel and cobalt bearing laterite ore. The low magnesium fraction of the laterite ore is leached with sulfuric acid at high pressure and temperature to solubilize the metal values while precipitating most of the solubilized iron as hematite or other iron compounds and a portion of the dissolved aluminum as alunite or other aluminum compounds. After reducing the pressure of the leach slurry to approximately atmospheric pressure, the pregnant leach slurry or solution is contacted with the high magnesium fraction of the ore to solubilize most of the nickel contained in the high-magnesium ore fraction while dissolving only a small portion of the iron content of the high magnesium ore fraction.

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.