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Gold in Industrial Applications

Gold plays an increasingly important role in industrial applications,particularly in electronics, despite its larger use in jewellery and investment products. As the annual statistics show (Gold Survey 2010, GFMS Ltd, London), some 300t or more of gold are used annually in electronic components such as ICs, contacts and circuitry, the latter notably as gold bonding wire.

Sales growth of electronic devices continues to boom and their in-built features continue to become ‘smarter and quicker’ each year, which has led to a substantial net increase in gold demand over recent years, even though specific gold content is being driven down due to thrifting and miniaturisation.

At the end of their use, electronic and other electrical product scrap offer an important recycling potential for the secondary supply of gold into the market. With gold concentrations reaching 300-350 g/t for mobile phone handsets and 200-250 g/t for computer circuit boards, this scrap is an ‘urban mine’ that is significantly richer in gold than the sources of the primary ores today.

However, as a forthcoming paper points out (C. Hagel√ľken and C.W. Corti, Gold Bulletin, vol 43 (3,) 2010), the ‘mineralology’ of such scrap products is very different to those of primary ores. Such scrap contains up to 60 different chemical elements that are intimately interlinked in complex assemblies and sub-assemblies. They are usually associated with organic materials that often incorporate halogenated flame retardants. Thus, specialised metallurgical processes with extensive offgas treatments are required to recover the gold and a wide range of other valuable metals in a cost-effective and environmentally sound way.

Equally importantly, the collection of such scrap from millions of households and businesses requires organised logistics to collect and bring the scrap to the recovery and refining facilities; this is undoubtedly a bigger challenge than the primary ore supply chain.