Patent ID: 7559972

Claim:
A process for the recovery of nickel and cobalt from a nickeliferous laterite ore including the steps of: a) providing a low magnesium limonite fraction and high magnesium saprolite fraction of a nickeliferous laterite ore; b) treating the limonite fraction with acid 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 at least one of goethite 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 or acid solutions has an ionic composition that contains sufficiently low levels of alkali metallic ions, sodium, potassium, and ammonia, to substantially avoid jarosite formation.