SUbstance flow analysis of the recycling of small waste electrical ...

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30 Substance flow analysis of the recycling of small WEEE The extraction of precious metals through mining is associated with significant environmental impacts like emissions of greenhouse gases, and consumption of energy, water and land (Ayres 1997). According to the Wuppertal Institute (2003), gold has a material intensity (MIT) of 540 000, which means that 540 tonnes of material have to be used to produce one gram of gold (Ritthoff et al. 2002). The MIT of silver is 7 500 (Wuppertal Institute 2003). Palladium has a MIT of 99 891 (primary production) or 2 394 (secondary production) (Saurat & Bringezu 2008). For comparison, primary copper has a MIT of 348.47 and secondary copper of 2.38 (Wuppertal Institute 2003). The environmental impacts of the secondary production of precious metals in state-of-the-art operations are much lower than primary production (Hagelüken & Meskers 2008). According to Saurat & Bringezu (2008), carbon dioxide equivalent emissions associated with secondary production of platinum-group metals in Europe are lower by a factor 13 than primary production outside of Europe, and sulphur dioxide equivalent emissions are lower by a factor 107. 2.3.2. Use of precious metals for manufacturing EEE Around 12% of the primary production of gold, 30% of the primary production of silver and 15% of the the primary production of palladium were used in 2006 for manufacturing EEE (Hagelüken & Meskers 2008). Precious metals are used in printed circuit boards (PCB) as a component of complex material mixtures, as they are mixed with or connected to other metals in contacts, connectors, cables, solders, hard disk drives, etc., with ceramics in multi layer capacitors, integrated circuits, hybrid ceramics, etc. or with plastics in PCB-tracks, interboard layers, integrated circuits, etc. (Hagelüken 2006a). The great advantage of gold is its high resistance to oxidation and corrosion and its high conductivity (Renner et al. 2000). Gold and gold alloys are used for conductor material and low-voltage contacts for communication and information transfer equipment, where even very thin oxide layers would cause interruptions or failures in signal transfer (Renner et al. 2000). Silver, due to its high electrical and thermal conductivity, is used as conductor and electrode material (Brumby et al. 2008). Palladium, pure or in combination with silver, is the most important component in pastes used for the production of inner electrodes of multilayer capacitors. Palladium is also used as a component in silver-based conductor pastes and for resistor elements in thick-film circuitry. Platinum finds application for data storage in harddisk drives, as barrier layers and as contact pads on semiconductor chips (Hagelüken & Meskers 2008, Renner et al. 2001). Table 3 gives a survey of the main application fields of gold, silver, palladium, platinum and their alloys.
2. Background and definitions 31 Table 3 Application of gold, gold alloys, silver and silver alloys, palladium and platinum in electronics (Schlamp 1996, Hagelüken & Meskers 2008) Gold Silver Bulk Bimetal Surface Coat electroplated sputtered or evaporated pastes, lacquers bonding wires for integrated circuits, transistors, diodes pressurecontact plates for power semiconduc tor devices Palladium bonding wires for transistors, diodes Platinum test resistors plug-in contacts plug-in contacts, pressurecontact and soldered base plates plug-in contacts PCBs, plug-in contacts, solderable and bond surfaces, switches, corrosion protection of semiconductor device packages PCB for high frequencies, system carrier, Mo and W base-plates, lead frames plug-in contacts thin film hybrid circuits, conductor contact, bond surfaces contact surfaces on Si diodes lead frames multilayer capacitors test resistors, diffusion barriers, magnetic data storage in harddisk drives thick film hybrid circuits, solderable areas for contacts, die-attach, IC technology Conductor pastes for thick film circuits, potentiometer capacitors, contact foils, screening, glass solders Conductor and electrode paste for thick-film circuits, multilayer capacitors solder connection special solders for die-attach, package soldering, and connections in semiconductor power devices tubes, package joining components, soft solders in semiconductor devices, dieattach Ag–Cu–Pd solders for electron tubes package joining 2.3.3. Relevance of precious metals in WEEE Although the concentrations of precious metals in the appliances are very low, in some equipment types these metals have a high economic and environmental relevance compared to other substances present in much higher quantity (e.g. iron, copper, plastics) (Herrmann 2004; Huisman 2004). The economic relevance of precious metals in WEEE was emphasized by Hagelüken (2006a), Koehnlechner (2008), Malhotra (1985) and Streicher- Porte et al. (2005). Precious metals make up more than 80% of the economic value of printed circuit boards in personal computers, mobile phones and calculators. For printed
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Page 4 and 5: Bibliografische Information Der Deu
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4. Data inventory 81 Due to the lim
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4. Data inventory 83 apparent gold.
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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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