ABSTRACT

Nickel (Ni) is a metallic element with an atomic weight of 58.71. The average concentration in the earth's crust is estimated to be 60-90 mg/kg but it is relatively depleted in acidic rocks and enriched in basic and ultrabasic rocks. The ore serpentine has a high content of nickel; the island of New Caledonia is largely built of serpentine rock — its soils are high in nickel, and nickel as well as cobalt and chromium is accumulated by the terrestrial plants and animals there (Hopkin, 1989). Nickel has a similar ionic radius and electronegativity to iron, cobalt and magnesium, and can therefore substitute for these elements in various minerals. The sulphide ores are particularly important commercially, with principal European producers being Norway, Finland, the German Democratic Republic (GDR), Albania and Greece. Reviews of the geochemistry and chemistry of nickel are published by Nriagu (1980) and the National Research Council, Canada (NRCC, 1981).