Compared to gold production of 2 500 tonnes per annum and the vast volumes of iron, copper and nickel that are mined every year, PGMs are a relatively rare commodity – only around 500 tonnes are mined annually, of which less than 200 tonnes are platinum. This is in contrast with the progressively more important role that they play in everyday life. These metals are increasingly found either in goods used every day, or are used in the production of such goods.

With rising global environmental awareness, the unique physical and chemical characteristics of PGMs, and their catalytic properties in particular, make them significant contributors to a cleaner and healthier environment through the reduction of air pollution.

PGMs and platinum in particular are referred to as “the green metals”.

• As a vital component in autocatalytic convertors, PGMs play a significant role in reducing air pollution by substantially limiting the discharge of carbon monoxide, hydrocarbons and nitrous oxides as well as particulates in diesel engines. According to the International Platinum Association (IPA). A car fitted with an autocatalytic convertor reduces noxious emissions by up to 5 tonnes over the vehicle’s 10-year life.
• PGMs are recyclable thus reducing waste whilst ensuring the sustainability of their supply. The most efficient recycling of PGMs occurs in the automotive sector, where a whole new industry has been developed to recycle autocatalytic convertors from scrapped vehicles. Autocatalysts were first used 35 years ago in the United States. The metal recovered from autocatalyst recycling is currently equivalent to 25% of the platinum used in new autocatalytic convertors. Much progress has been made with recycling and waste reduction initiatives. Platinum jewellery recycling in Japan increased markedly last year due to the high price.
• Fuel cells are being developed both as portable and auxiliary energy units and as a source of power for vehicles. This technology generates electricity via an electro-chemical reaction in which oxygen and hydrogen combine over a platinum catalyst. As this process is carbon-free, fuel cells have the potential to reduce air pollution considerably while significantly increasing the efficiency of cars and power generators and at the same time reducing the demand for fossil fuels. According to the US State Department, if just 10% of vehicles use fuel cells, regulated air pollutants would be reduced by 1 million tonnes and greenhouse gases (GHGs) by 60 million tonnes annually.

Platinum, one of the most common and widely used of the PGMs, is (given its chemical and physical characteristics, and its excellent catalytic properties), ideally suited to advanced technological applications. Silvery white in colour and extremely durable in nature, platinum is one of the densest and heaviest metals. It is extremely malleable and ductile, and is exceptionally stable at high temperatures with a melting point in excess of 1 700^oC. Platinum is primarily used in catalytic convertors in the automotive industry and in jewellery.

Palladium is the most abundant of the PGMs. Given its catalytic properties, it is also a vital component in catalytic convertors and air purification equipment. Palladium is frequently used as an alloy and as a substitute for platinum in catalysts, electrical contacts, dental alloys and jewellery.

 

Rhodium is also a vital component in industrial catalytic systems, particularly in the automotive industry where it is used in the reduction of NOx to nitrogen. Rhodium, alloyed with other PGMs, is used in furnace windings, thermocouple elements, fibre glass production, laboratory crucibles and electrodes for spark plugs.