Nickel resources are typically classified as sulphides or laterites. Approximately 73% of the world’s nickel resources are estimated to be contained in laterites while 27% are as classified as sulphide. Currently, some 37% of the world’s nickel supply is derived from sulphide resources and almost all of the sulphides utilized now are massive sulphide ores, as opposed to disseminated sulphides.

In conventional pyrometallurgical processing, the ore is dried, calcined (and sometimes reduced) in a rotary kiln and smelted in an electric furnace in the presence of carbon. If matte is the desired product, then sulfur is added to the kiln. The crude metal/matte is further processed/refined to produce the final product.