Process for enhanced acid leaching of laterite ores

摘要

A process is described for the recovery of nickel and cobalt from a nickeliferous laterite ore including the steps of: a) providing a nickeliferous laterite ore and separating that ore into its low magnesium limonite fraction and high magnesium saprolite fraction; b) treating the limonite fraction in acid solution in a primary high pressure leach step to produce a primary leach slurry; c) adding the saprolite fraction to the primary leach slurry to initiate precipitation of iron as goethite and/or hematite, while simultaneously releasing further acid from the iron precipitation, to effect a secondary atmospheric leach step, producing a secondary leach slurry; wherein all water used to prepare the ore slurries and/or acid solutions has an ionic composition that substantially avoids jarosite formation.