15. Recycling of Precious and Special Metals

The term technology metals is used in this chapter as a synonym for the precious metals (Au, Ag, and the PGMs Pt, Pd, Rh, Ru, Ir) plus the special/specialty metals (among others In, Ga, Ge, rare earth elements, Sb, Se, Si, Te).

For example, indium recycling gets increasingly more difficult for target manufacturing  →  spent ITO target  →  scrapings from the sputtering chamber  →  broken or out-of-spec LCD glass  →  entire out-of-spec or obsolete LCD monitor.

One example is PGM loss from car catalysts: In contrast to earlier conditions, today’s autocatalysts under European or American driving conditions emit hardly any PGMs during the use phase. However, under typical ‘developing country’ driving conditions (e.g. bad roads, low car maintenance, misfires, bad petrol quality), a catalyst is likely to be mechanically destroyed, and with broken ceramic catalyst, PGMs are blown out from the exhaust and dissipated along the roadside.

Examples are tantalum or rare earth elements used in electronic applications. Present only in very low concentrations (e.g. in circuit boards), they dilute even more into the slag. Due to their dispersion/dilution, the additional energy needed to recover and recycle the metal can exceed the energy requirement for virgin extraction.

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Net value  =  recovered metals’ value minus smelting and refining charges (not considering costs of collection, preprocessing, and shipment in the preceding recycling chain). Value can vary significantly depending on specific quality/type (especially for autocatalysts).

Areas of investigation include all relevant application segments for PGMs: automotive catalysts, chemical and oil refining catalysts, glass manufacturing, dental applications, electronics, jewellery, electroplating, fuel cells, etc.

It is estimated that about 50% of used IT electronics leave Europe one way or another. For mobile phones, less than 5% of the theoretical recycling potential is currently being realised globally in a compliant way. For 2006, monitoring results for ELV in Germany showed that out of 3.2 million deregistered passenger cars, only 504,000 were recycled in Germany, while 2.06 million were exported as ‘used cars’. A gap of 640,000 cars addresses mainly unregistered exports. A recycling rate of 86.2% was reported (Umweltbundesamt 2008), but this refers only to the 504,000 cars scrapped in Germany. Calculated on the 3.2 million deregistrations, Germany’s recycling rate would fall to 13.5%. Although 1.8 million of the exported cars go primarily into other (mainly Eastern) EU states, it can be assumed that a big portion will ultimately leave Europe. The export of about 2.5 million cars represents a secondary materials potential of 1.3 million tonnes of steel, 180,000 t aluminium, about 110,000 t of other nonferrous metals, and about 6 t of PGM. Significant quantities of ELVs are also exported from other European countries (Buchert et al. 2007).