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

84 Substance flow analysis of the recycling of small WEEE
Data on the concentration of precious metals in some equipment types are directly available
in the literature (see Appendix 2). Hagelüken & Buchert (2008) measured in 105 tonnes of
end-of-life mobile phones (without battery) an average gold concentration of 347 grams per
tonne and an average palladium concentration of 151 grams per tonne. For personal
computers, Gmünder (2007) reports a gold concentration of 26.7 grams per tonne of PCs,
and a palladium concentration of 12.3 g/t. Shirahase et al. (2007) reported that one tonne of
PCs contains 13 grams of gold and 17 grams of palladium. The Microelectronics and
Computer Technology Corporation (MCC 1996) mentioned an average gold concentration of
16 g/t and a palladium concentration of 3 g/t in computers including central units and CRT
monitors. Because of the conflicting values in the literature, calculations were conducted
(Table 32), showing that PCs contain around 31 g/t of gold and 13 g/t of palladium.
Table 32
Precious metals concentration in personal computers
Component Reference Mass
fraction of
part in PC
PM concentration
(g/t in part)
PM concentration
(g/t in PC)
Gold Palladium Gold Palladium
PCB from central unit Hagelüken 2007 8.9% 250 110 22.3 9.8
Processor Analysis at Umicore 0.2% 2737 27 5.2 0.1
PCB from CD drive Gmünder, 2007 0.6% 87.5 52 0.6 0.3
PCB from floppy drive Gmünder, 2007 0.4% 112 203 0.4 0.8
PCB from hard drive Gmünder, 2007 0.5% 415 286 2.2 1.5
PCB from power supply Gmünder, 2007 2.1% 10 17 0.2 0.4
Total 30.8 12.8
The concentration of precious metals in the other equipment groups was determined by
using the formula presented in chapter 3.3.1, assuming that only printed circuit boards
contain precious metals. Appendix 3 compiles literature data on the concentrations of silver,
gold, palladium and platinum in printed circuit boards from different equipment types
published by several authors. Sampling issues, time and place of the investigation and
applied analysis method may explain the discrepancies of the results. Table 33 presents the
estimated average concentrations of gold and palladium in the different equipment groups in
Germany and in the USA. Details on the calculations, which results for Germany differ
slightly from the results for the USA, can be found in Appendix 6. The variation coefficient is
assumed to vary according to the equipment groups and to amount to:
5% for mobile phones,
10% for desktop personal computers,
20% for the remaining four equipment groups.