Lateritic nickel ore deposits are surficial, weathered rinds formed on ultramafic rocks.
[1] Lateritic nickel ores formed by intensive tropical weathering of olivine-rich ultramafic rocks such as dunite, peridotite and komatiite and their serpentinized derivatives, serpentinite which consist largely of the magnesium silicate serpentine and contains approx.
Nickel is turned into usable quality ore grade by being merged into the newly formed stable minerals.
In pockets and fissures of the serpentinite rock green garnierite can be present in minor quantities, but with high nickel contents – mostly 20–40%.
[citation needed] Ore deposits of this type are restricted to the weathering mantle developed above ultramafic rocks.
Another hydrometallurgical routes is the Caron process, which consists of roasting followed by ammonia leaching and precipitation as nickel carbonate.
Ore is ground, agglomerated, and perhaps mixed with clay-poor rock, to prevent compaction of the clay-like materials and so maintain permeability.
The ore is stacked on impermeable plastic membranes and acid is percolated over the heap, generally for 3 to 4 months, at which stage 60% to 70% of the nickel-cobalt content is liberated into acid solution, which is then neutralised with limestone and a nickel-cobalt hydroxide intermediate product is generated, generally then sent to a smelter for refining.
Another new method of extracting nickel from laterite ores is currently being demonstrated at a pilot scale test plant at the CSIRO facility in Perth Australia.