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82 Substance flow analysis of the recycling of small WEEE The recovery rates for precious metals achieved by the processes for recovery of precious metals of the formal sector was estimated by several authors to exceed 90% (Table 30). A differentiation between recovery of precious metals from the sWEEE generated in Germany and in the USA was not necessary, because the materials are commodities traded on a global scale. It is very common that precious metals from printed circuit boards from a preprocessing facility in the USA are recovered in Europe. Table 30 Recovery rates for gold and palladium achieved by the recovery processes of the formal sector Reference Recovery rate for gold Recovery rate for palladium Huisman (2004) > 99% > 99% Deubzer (2007) 98% 99% Hagelüken & Meskers (2008) >95% 1 5% are lost in the copper smelter, and 1% during palladium refining The recovery rates in the recovery processes were assumed to be 98% for gold and palladium. The overall recovery rates achieved by the whole process chain of the formal treatment are presented in Table 31. In both regions, the highest recovery rates are achieved for mobile telephones and personal computers, and the lowest for low-grade equipment. For Germany, the quantification of the uncertainties of the recovery rates is based on the statistical analysis of the experimental results presented in Paper 2. The variation coefficient was assumed to amount to 10%. For the USA, where no quantitative data are available, the variation coefficient was assumed to amount to 20%. Table 31 Recovery rates for gold and palladium achieved by formal treatment of sWEEE in Germany and in the USA in 2007 Country Germany USA Mobile telephone 60% 74% Desktop personal computer 58% 74% CRT monitor 59% 59% Large high-grade equipment Small high-grade equipment 39% 49% 39% 49% Low-grade equipment 28% 29% Keller (2006) investigated the processes applied in the informal sector to recover gold from printed circuit boards in Bangalore in India. Two different processes were compared, both beginning with the dismantling of printed circuit boards to remove the parts containing
4. Data inventory 83 apparent gold. Afterwards, the gold was recovered by cyanide leaching (process 1) or gold stripping (process 2). Figure 13 presents the results of the substance flow analysis. Between 40% and 84% of the gold contained in the printed circuit boards (basic raw material) was lost during pre-processing, mainly because of the visual checking for apparent gold. The recovery of gold through chemical processes causes further losses, so that in total, only 8% to 18% of the gold is recovered (Figure 13). Figure 13 Gold yields of two recycling processes for printed circuit boards in Bangalore; BRM= Basic raw material (printed circuit boards), IM= Input material (apparent gold parts) (Keller 2006) In this thesis, it was assumed that the chain of treatment processes applied by the informal sector allows the recovery of 13% of the gold. The variation coefficient was assumed to amount to 10%, which means that 10% to 16% of the gold is assumed to be recovered during treatment in the informal sector. Palladium is usually not recovered by the informal sector (assumed recovery rate of 0%). 4.2. Concentration of precious metals in sWEEE The quantification of the metal flows requires knowledge of the average concentration of gold and palladium in the equipment groups. As presented in chapter 3.3.1, the concentration of precious metals in the different equipment groups was assumed to be constant in the entire system.
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ITU-Schriftenreihe, 2010 Institut f
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Bibliografische Information Der Deu
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Acknowledgements Here I would like
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Kurzfassung Die Nachfrage nach Edel
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Composition of the doctoral thesis
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4.1.1. Generation .................
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Figure 25 Flows of gold and palladi
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Table 26 Quantity of sWEEE (includi
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List of abbreviations Ag Au BAT CE
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1. Introduction and objectives of t
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2. Background and definitions 23 Du
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2. Background and definitions 27 2.
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2. Background and definitions 29 pu
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Page 125 and 126: 8. Conclusion 125 All the equipment
Page 127 and 128: References 127 Binder 2007 BITKOM 2
Page 129 and 130: References 129 CIWMB 2004b Clift &
Page 131 and 132: References 131 Greenpeace 2005 Gree
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References 133 Janz & Bilitewski 20
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References 135 Melissen 2006 Mesker
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References 137 Rhein et al. 2008 Rh
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References 139 StEP 2009 Stevels 20
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References 141 Veldhuizen & Sippel
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References 143 Legislative texts Ba
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Appendices 145 Appendix 1 Equipment
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Appendices 147 Appendix 2 Average c
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Appendices 149 Appendix 4 Past and
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Appendices 151 Eq. group Equipment
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Appendices 153 2 Assumptions based
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Appendices 159 Appendix 8 Flows of
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Appendices 161 Appendix 10 Flows of
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