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40 Substance flow analysis of the recycling of small WEEE Scheidt et al. (2008) distinguished the following methods of reuse: (1) sell the product to another user, (2) donate the product to another user, (3) if the product is damaged, restore the product prior to moving it to another user and (4) harvest components from it. Regarding re-use of WEEE in practice, three kinds of re-use activities can be differentiated: Re-use of working equipment, Re-use of equipment after repair and/or refurbishment, and Re-use of parts or components. Re-use processes fall under the scope of some guidelines on WEEE management (Appendix 4 summarizes the scope and other information on these guidelines). Li et al. (2008) wrote that before entering the waste stream, there is “huge” potential for re-use of EEE, but only 1.27% of products in the WEEE collection system in Germany are economically reusable. According to Rose & Stevels (2001), discarded consumer EEE in Europe is regarded as economically or technically so old that higher levels of reuse options are usually not attractive. In the USA, managers of end-of-life facilities indicated that only about 10 to 15% of residential WEEE, which is typically much older and more heterogeneous than commercial WEEE, has resale value. About 90% of the commercially generated IT waste equipment had resale value, but less than 50% is refurbished and resold due to customer requirements that equipment should be destroyed (Rifer et al. 2009). 2.4.4. Treatment The chain of pre-processing, recovery and disposal processes used to recover the materials and substances contained in sWEEE (Figure 3) is called in this thesis the ‘treatment process chain’. According to the WEEE Directive, ‘treatment’ means any activity after the WEEE has been handed over to a facility for depollution, disassembly, shredding, recovery or preparation for disposal and any other operation carried out for the recovery and/or the disposal of the WEEE. Recommendations for treating WEEE in the form of standards, manuals and guidelines have been issued by different groups (Appendix 4). The actual amount of precious metals recovered, and hence the amount of precious metals leaving the cycle, depends on the overall efficiency of the chain of material recovery processes during the end-of-life phase. In turn, this efficiency is affected by both the design of the product and the combination of preprocessing and recovery processes in the end-of-life phase (Castro et al. 2005). 2.4.4.1. Pre-processing As first step of the treatment process chain, pre-processing determines to which recovery or disposal processes the materials are fed (Paper 2). Pre-processing is divided into three major stages: (1) sorting, (2) selective disassembly, targeting on singling out (liberating)
2. Background and definitions 41 hazardous or valuable components and (3) upgrading, using mechanical/physical processing and/or metallurgical processing to prepare the materials for the final refining process (Cui & Forssberg 2003). In the European Union, the pre-processing must fulfil the requirements on selective treatment of certain assemblies of materials defined in the WEEE Directive. Preprocessing must also ensure that hazardous materials are prepared for disposal in an environmentally-sound way. Ferrous metals, non-ferrous metals, cables, printed circuit boards, plastics, capacitors, batteries and others (for example glass, wood and hazardous materials containing mercury) are typical output fractions of sWEEE pre-processing (Hischier et al. 2005). Pre-processing can be carried out: manually, mechanically (automatic size reduction and sorting of materials through successive sorting process units) or with a semi-automatic process combining manual and mechanical techniques. A high variety of technologies for automatic size reduction are available on the market (for example hammer mills, chain shredders or rotary shears). Cui & Forssberg (2003) present automatic sorting technologies that can be found in pre-processing facilities. Gmünder (2007), Willems et al. (2006) and Zhang & Forssberg (1998) discuss the advantages and limitations of applying and combining the different technologies. By pre-processing WEEE, like by processing mineral ores, the so-called 'concentration dilemma' or ‘grade-recovery function’ applies (Hagelüken 2006a, Hodouin et al. 2001). Figure 5 illustrates the concentration dilemma. The recovery of a specific material (for example metal) from an input stream decreases with increasing purity requirements on that material separated into an output fraction. The optimum operating conditions for preprocessing are, therefore, a compromise between grade (quality) and recovery (quantity), in order to minimize the losses and at the same time to produce output materials with an acceptable quality.
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Page 4 and 5: Bibliografische Information Der Deu
Page 7 and 8: Acknowledgements Here I would like
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7. Recommendations 109 7. Recommend
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7. Recommendations 111 WEEE contai
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7. Recommendations 113 After collec
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7. Recommendations 115 in the case
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7. Recommendations 117 In many case
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7. Recommendations 119 manufacturer
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7. Recommendations 121 the manufact
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7. Recommendations 123 Reuter et al
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8. Conclusion 125 All the equipment
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References 127 Binder 2007 BITKOM 2
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References 129 CIWMB 2004b Clift &
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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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