Modelling of nickel laterite smelting to ferronickel

Most nickel is produced as the metal, but about a third of the world's new nickel is ferronickel. World annual production of ferronickel is around 250,000 tonnes, with the two largest producers being BHP Billiton and Societe Le Nickel (Cartman, 2010). Most of the world's accessible nickel reserves are oxidic ores called “laterite” (Sudol, 2005), and are the result of chemical weathering and supergene enrichment of mafic/ultramafic rocks. They vary greatly in depth, nickel grade and mineralogy (Dalvi et al., 2004). The lower layers are called “saprolite” and have nickel contents from 1.8 to 3 wt-%, relatively low iron contents but high magnesia and silica contents and are suited to pyrometallurgical processing (Cartman, 2010).