Environmental Engineering Reference
In-Depth Information
Generally, the base metals used in high volume are not “consumed” in the
sense that they are at the end of use converted into an irrecoverable state.
Thus, metals such as iron or aluminum used in construction or packaging
can be recovered and recycled extending the lifetime of the resource. While
thereareinevitablelossesinreuseorrecyclingoperations,itcansaveenergy
and reduce the pollution load on the environment (Gordon et al., 2006).
Energy savings in recycling of steel, aluminum, copper, and lead are
estimated to be 74, 95, 85, and 65%, respectively (Steinbach and Wellmer,
2010).
1.2.3 Critical Materials
A class of materials increasingly used in a variety of high-technology and
emergingenergyapplicationsistherareearthandplatinumgroupmetals.
20
However, future technologies such as electric vehicles, displays,
next-generation solar panels, and advances in wind power rely on the
availability of these metals. For instance, the world demand for neodymium
used in magnets and laser applications will be 40,000 tons/year by 2030;
this compares with the demand of only 7000 tons in 2006 (European
Environment Agency, 2010). The US DOE has identified several critical
materials in this category that will be in short supply in the United States
within the next couple of decades. A strong growth in short-term demand is
expected at the very least for Te, In, and Ge. The periodic table in
Figure 1.9
highlights these and also indicates those regarded as being critical materials
in the European Union.
Applicationsofcriticalmetalsaredissipative,andpost-userecoveryiseither
impractical or impossible. In theory, the low-volume, high-value critical
metals can also be recycled effectively. Often, these are used in complex
constructssuchasthinlayersusedinsolarpanels.Theprocessestoseparate
out the components in recycling are complicated and costly. A recent UNEP
report (UNEP, 2011b) suggests global rates of post-use recycling of these to
be less than 1% (1.35% for tantalum).
Table 1.3
summarizes some typical
exemplary uses of critical metals.
