Platinum metallurgy — Ores and processes

Although known for over two millennia, platinum has only been used industrially for around 150 years. Its physical and chemical properties, in particular its very high melting point, resistance to chemical attack, catalytic activity, malleability and mechanical strength, have made it indispensable for use in catalysis, electronics, dentistry, jewelry, chemistry and petrochemistry, the glass industry and many other applications. Platinum is combined with other elements to form the platinoids: platinum (Pt), palladium (Pd), rhodium (Rh), osmium (Os), iridium (Ir) and ruthenium (Ru).

The largest reserves are in South Africa and Russia. The deposits are largely associated with ultrabasic dunitic and gabbroic rocks, where PGMs are associated with copper, nickel and iron sulfides.

Production is concentrated in three countries: South Africa, Russia and Canada. Consumer countries are mainly in North America, Western Europe and Japan.

Industrial processes depend on the main types of deposit. For placer deposits, enrichment methods are based on gravity, while for sulfide deposits, the general method is to float platinum-bearing sulfides.

Pyrometallurgy, reserved for sulfide concentrates, is based on smelting for matting and conversion. Residues from copper and nickel metallurgy are therefore enriched in PGMs and also contain gold and silver. They are processed by mixed methods combining pyrometallurgy and hydrometallurgy.

Chloride hydrometallurgy is used to separate PGMs from each other.

A second article by the same authors presents aspects linked to the industrial exploitation of platinoids: several case studies, recycling, environment, health and safety.