The treatment of nickel ores and concentrates and the subsequent
processing to recover separate products of nickel and cobalt is one of the
major interests at present in the mining industry. The increasing demand
for nickel, and more recently also cobalt, has led to increased exploration
for ore sources. Major discoveries have resulted in Canada and Australia.
These deposits, as well as others already known, are presently being
developed and the process technology tested and evaluated for
applicability to the different mineralogical types - mainly sulphide,
arsenide and oxide laterites. Concentrates may be treated by either hydro- or pyrometallurgical
processes, while the nickel laterites are best suited to hydrometallurgical
processing. However, if hydrometallurgy is used, once the ore or
concentrate is leached the resultant solutions are then amenable to similar
separation technologies for purification and recovery of high purity nickel
and cobalt products. Solvent extraction, together with other separation processes such as
precipitation, can produce high purity solutions of nickel and cobalt. The
final products of these solutions may be nickel and cobalt cathodes, metal
powders precipitates or salts, depending on the final process of
electrowinning, hydrogen reduction, precipitation, or crystallisation
Respectively.