Mining & Production
The six platinum group metals (PGMs) occur together in nature alongside nickel and copper.
South Africa is the world's leading platinum producer and the second largest palladium producer after Russia, where production is concentrated in the Norilsk region.
All of South Africa's production is sourced from the Bushveld Igneous Complex, which hosts the world's largest resource of PGMs. In addition to platinum and palladium, these mines also produce rhodium, ruthenium, iridium, gold, silver, nickel, copper, cobalt, ammonium sulphate and sulphuric acid as by-products.
Platinum and palladium have the greatest economic importance and are found in the largest quantities. The other four - iridium, rhodium, ruthenium and osmium - are produced only as co-products of platinum and palladium and are never likely to be mined for their own sake.
It is a capital and labour intensive industry, taking up to six months, and requiring 7 to 12 tonnes of ore to produce one troy ounce (31.135 grammes) of platinum. Companies are investing heavily in exploration and production facilities to ensure the future supply of these vital metals.
Extraction & Refining
PGM ore is mined underground and less usually in open-cast pits. It is blasted out of the ground before being crushed and milled into smaller rock particles which are mixed with water and reagents and pumped through with air to form a "froth flotation".
PGM-rich particles adhere to the bubbles created by this process. They are then removed at the surface and the remaining material is put through the process a second time.
When dried, the flotation concentrate is smelted at temperatures that may be over 1500 °C and a mixture of the metals is separated from unwanted minerals such as iron and sulphur by air being blown through.
Nickel, copper and cobalt are separated and refined using electrolytic techniques leaving rich residues which require the separation and purification of the remaining PGMs, gold and silver. This part of the process is an intricate combination of solvent extraction, distillation and ion-exchange techniques.
Finally, the soluble metals, which dissolve in hydrochloric acid and chlorine gas, are obtained: first gold and then palladium and platinum. The insoluble PGMs (rhodium, iridium, ruthenium and osmium) are the last to be extracted.