Precious metals recycling

The recovery and recycling of production waste and end-of-life products make raw materials renewable. The recovery of precious metals (platinum Pt, palladium Pd, rhodium Rh, gold Au and silver Ag) makes a significant economic contribution to sustainable development. While recycling accounts for around a third of French industry's overall metal requirements, the situation is paradoxically no better for precious metals, where recycling accounts for just a few dozen percent of consumption. This situation can be explained by the fact that precious metals are only systematically regenerated if they are used in an industrial process (refractory or Pt catalyst). When they are used in the composition of products, the quantities used are infinitesimal and the "deposits" are poor and scattered. What's more, their natural inalterability means that the jewelry sector makes only a small contribution.

The use of Pt-Pd-Rh in automotive catalysis (purification of combustion gases by catalytic converters), which is by far the most important sector for the use of platinoids in France (90% of uses), is recent (EURO I standard came into force on 01/01/93): the first generation of vehicles fitted with catalytic converters is just reaching the end of its life. The French automotive industry uses around 4.5 t of Pt and 9 t of Pd, compared with around 42 t of Pt and 67 t of Pd in the global automotive industry. Catalytic converter processing therefore has an extraordinary national and global impact.

Electronic scrap is considered to be one of the main materials to be recycled, as it contains both precious metals (Pt, Pd, Rh, Au, Ag) and base metals, which can be hazardous as heavy metals for the environment. The development of computer technology, automation and, more generally, the industries that feed the audiovisual sector, means that we can expect an abundance of this type of waste to be recycled, although the decreasing quantities of precious metals used, the miniaturization of components and the decline in activity in the armaments sector work in the opposite direction. At present, only 10% of electronic waste is recycled in Europe, as the cost of recovery is often higher than that of the value contained in the waste.

The position of gold recycling is harder to pin down. In France, 75% of gold is consumed in the jewelry sector, and 85% worldwide. Recycling accounts for perhaps 10-20% of the total in France, mainly from remelted jewelry gold and to a very limited extent from electronic scrap. For example, in the photographic sector, which is the biggest consumer of silver in France, recycling, which involves the electrolysis of developing baths and the incineration of used radios and films, covers a third of the photographic industry's needs. But the average...