Substance flow analysis of the recycling of small waste electrical and electronic equipment An assessment of the recovery of gold and palladium Perrine
The demand for precious metals by manufacturers of electrical and electronic equipment has increased significantly over the past few years. Although precious metal concentrations in appliances are very low, these metals have a high economic and environmental relevance compared to other substances present at much higher levels (for example iron, copper, plastics).
This thesis aims at describing and quantifying the flows of small waste electrical and electronic equipment (sWEEE) in Germany and in the USA for the year 2007, as well as the flows of gold and palladium associated with the sWEEE. Although collection systems have been set up, in many cases sWEEE is not collected separately for recycling but instead is disposed of. Regarding treatment of sWEEE, the model differentiates between reuse and treatments carried out by the formal and informal sector (including illegal export of sWEEE).
The material flows were quantified based on a combination of expansive experimental investigations and a review of the relevant literature. The results revealed that, in 2007, 370 000 to 430 000 tonnes of sWEEE were generated in Germany, containing 1.9 to 2.4 tonnes of gold and 580 to 720 kg of palladium. In the USA, 26 to 36 tonnes of gold and 9 to 12 tonnes of palladium were contained in the 3.1 to 4.3 million tonnes of sWEEE generated in 2007. In Germany, the collection rates are much higher (77% of the generated sWEEE is collected) than in the USA (30%). In the USA, 6% of the generated sWEEE is reused, whereas in Germany the reuse rate amounts to 3%. 72% of the gold contained in the sWEEE was discarded in Germany and therefore lost for the recycling economy. The discarding rate is around 75% for the USA. The economic value of the discarded gold and palladium in 2007 amounted to 34 to 44 million US-dollars in Germany and 466 to 714 million US-dollars in the USA.
In conclusion, the recycling infrastructures in Germany and in the USA do not allow an efficient recovery of the precious metals. The losses are caused by the non-separated collection of sWEEE and by inappropriate treatment, for instance during pre-processing. The characteristics of the different types of sWEEE considerably influence the recovery of precious metals. This has to be considered by developing strategies to improve it. Besides the recommendations how to improve the system, some suggestions to improve the data collection for the conduction of further substance flow analyses were formulated. The applied methodology can be used to assess waste management systems and develop improvement strategies. The method is not only useful for assessing the recovery of valuable substances as presented in this thesis, but in a more general way allows a quantitative analysis of the destination of substances fed into a waste management system.