Secondary Production & Recycling
The secondary production of PGMs includes the recycling of these metals from industrial applications and end-of-life products, as well as the recovery of metals from by-products and residues created in primary production. Secondary production plays an important role in lowering the environmental footprint of global PGM production and contributes a significant part of the PGM supply; e.g. for autocatalysts, recovery of PGMs from end-of-life vehicles was equivalent to 30% of gross demand in 2010.
"Secondary production in the PGM life cycle"
It is achieved through a complex, global web of companies, processes and material flows arranged to maximize the efficiency of PGM recovery from a variety of sources. Typically, PGM-containing materials from industrial applications and by-products & residues are received directly by secondary producers, while consumer products must be first collected from consumers and pre-processed to separate the PGM-containing components from other materials (e.g. removal of autocatalyst from a vehicle).
Smelting or Dissolving
Secondary production is composed of two processes. First, PGM-containing materials are either smelted to form a molten metal matte, or dissolved to bring the PGMs into a solution. Second, the PGM-enriched output from step one is then refined to recover the individual metals separately in a pure form identical to that from primary production.
Using state-of-the art recycling technologies, over 95% of the PGM content of spent automotive catalysts (and other PGM-containing materials) can be repeatedly recovered.
PGM materials that are collected at a very high rate or enter secondary production directly from industrial processes, such as industrial catalysts, are recycled at a rate near the 95% maximum potential. For PGMs in consumer products, however, end-of-life recycling rates are lower, as high recovery requires an efficient recycling chain from collection to refining. Unfortunately, a well-functioning chain that targets PGM recovery is not always in place when these products reach their ultimate end-of-life and are ready for recycling. Thus, the end-of-life recycling rate for these PGMs is largely determined by the weakest link in the chain for the specific product.
Targeting the weakest link in the chain provides the best opportunity for improving the recycling rate of PGMs, which in turn can help reduce the overall environmental impact of the PGM supply.