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114 Substance <strong>flow</strong> <strong>analysis</strong> <strong>of</strong> <strong>the</strong> <strong>recycling</strong> <strong>of</strong> <strong>small</strong> WEEE<br />

technological innovations enable <strong>the</strong> achievement <strong>of</strong> higher recovery rates for precious<br />

metals, obviously <strong>the</strong>y should be used.<br />

Table 39<br />

Recommendations for pre-processing <strong>the</strong> WEEE depending on <strong>the</strong> equipment groups, in<br />

order to limit <strong>the</strong> losses <strong>of</strong> precious-metals during treatment<br />

Group<br />

Mobile telephone<br />

Desktop personal<br />

computer<br />

O<strong>the</strong>r substance <strong>of</strong><br />

concern<br />

Plastics, non-ferrous<br />

metals<br />

Ferrous metals<br />

Recommendation for pre-processing to limit <strong>the</strong><br />

discard <strong>of</strong> precious metals<br />

Direct feed into a state-<strong>of</strong>-<strong>the</strong>-art recovery process for<br />

precious metals after removal <strong>of</strong> <strong>the</strong> battery<br />

Manual removal <strong>of</strong> <strong>the</strong> entire printed circuit boards<br />

CRT monitor Lead, plastics Removal <strong>of</strong> <strong>the</strong> printed circuit boards<br />

Large high-grade<br />

equipment<br />

Small high-grade<br />

equipment<br />

Low-grade<br />

equipment<br />

Plastics, ferrous and nonferrous<br />

metals<br />

Plastics, o<strong>the</strong>r non-ferrous<br />

metals<br />

Plastics, o<strong>the</strong>r ferrous and<br />

non-ferrous metals<br />

Manual dismantling or “gentle” mechanical treatment<br />

to sort out <strong>the</strong> printed circuit boards<br />

Direct feed into a state-<strong>of</strong>-<strong>the</strong>-art recovery process for<br />

precious metals after removal <strong>of</strong> <strong>the</strong> battery<br />

Advanced mechanical treatment with sorting <strong>of</strong> <strong>the</strong><br />

printed-circuit boards<br />

Even though <strong>the</strong> recovery <strong>of</strong> precious metals is <strong>the</strong> main focus <strong>of</strong> <strong>the</strong> recommendations,<br />

o<strong>the</strong>r relevant materials contained in <strong>the</strong> <strong>waste</strong> and some cost-benefits considerations were<br />

qualitatively taken into account. Despite <strong>the</strong> lack <strong>of</strong> quantitative data, it was necessary to<br />

keep in mind <strong>the</strong> trade-<strong>of</strong>f between increase <strong>of</strong> <strong>the</strong> recovery <strong>of</strong> precious metals and decrease<br />

<strong>of</strong> <strong>the</strong> recovery <strong>of</strong> o<strong>the</strong>r materials, due to <strong>the</strong> grade-recovery function (Figure 5). To measure<br />

<strong>the</strong> relevance <strong>of</strong> <strong>the</strong> materials and define <strong>recycling</strong> priorities, some indicators measuring<br />

<strong>the</strong> environmental impacts <strong>of</strong> materials like <strong>the</strong> ’material intensity’ (MIT) developed by <strong>the</strong><br />

Wuppertal Institute (Ritth<strong>of</strong>f et al. 2002), <strong>the</strong> ‘Eco-Indicator ’99’ (Goedkoop & Spriensma<br />

2000), <strong>the</strong> ‘environmental value’ (Huisman 2003) and <strong>the</strong> ‘Fraunh<strong>of</strong>er IZM Toxic Potential<br />

Indicator’ (Middendorf et al. 2000) can be applied. Shirahase et al. (2007) provided a<br />

comparison <strong>of</strong> different weighting methods to quantify <strong>the</strong> recovery priority <strong>of</strong> metals<br />

contained in printed circuit boards, considering <strong>the</strong> amount <strong>of</strong> reserves, <strong>the</strong> amount <strong>of</strong><br />

production, <strong>the</strong> prices and o<strong>the</strong>r parameters relating to <strong>the</strong> different metals. A possible option<br />

to set <strong>recycling</strong> priorities is to promote <strong>the</strong> recovery <strong>of</strong> <strong>the</strong> most mass-relevant materials, as<br />

required by <strong>the</strong> WEEE Directive. This approach was criticised in Paper 2, as well as by<br />

Huisman et al. (2007) and Reuter et al. (2005). The relevance <strong>of</strong> <strong>the</strong> materials can also be<br />

measured with an economic approach, by aiming at recovering <strong>the</strong> materials that bring <strong>the</strong><br />

highest economic revenues.<br />

For appliances that are very rich in precious metals, like personal computers, a manual<br />

removal <strong>of</strong> <strong>the</strong> printed circuit boards is recommended. If this is not economically feasible, like

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