A process for the recovery of nickel and cobalt from nickel and cobalt
containing ores, including the steps of first leaching a laterite ore
and/or a partially oxidised sulfide ore with an acid solution to produce
a pregnant leach solution containing at least dissolved nickel, cobalt
and ferric ions, and subsequently leaching a sulfide ore or concentrate
with the pregnant leach solution to produce a product liquor.
Alternatively, the laterite ore and/or partially oxidised sulfide ore can
be leached in a combined leach with the sulfide ore or concentrate. The
ferric ion content in the pregnant leach solution or in the combined
leach is sufficient to maintain the oxidation and reduction potential in
the sulfide leach high enough to assist in leaching nickel from the
sulfide ore or concentrate.