7.3.6 Materials efficiency and recycling
Materials efficiency refers to the reduction of energy use by the appropriate choice of materials and recycling. Many of these options are applicable to the transport and building sectors and are discussed in Chapter 5, section 5.3.1 and Chapter 6, section 6.4. Recycling is the best-documented material efficiency option for the industrial sector. Recycling of steel in electric arc furnaces accounts about a third of world production and typically uses 60–70% less energy (De Beer et al., 1998). This technology, and options for further energy savings, are discussed in Section 7.4.1. Recycling aluminium requires only 5% of the energy of primary aluminium production. Recycled aluminium from used products and sources outside the aluminium industry now constitutes 33% of world supply and is forecast to rise to 40% by 2025 (IAI, 2006b, Martcheck, 2006). Recycling is also an important energy saving factor in other non-ferrous metal industries, as well as the glass and plastics industries (GOI, various issues). Recycling occurs both internally within plants and externally in the waste management sector (See Section 10.4.5).
Materials substitution, for example the addition of wastes (blast furnace slag, fly ash) and geo-polymers to clinker to reduce CO2 emissions from cement manufacture (See Section 18.104.22.168), is also applicable to the industrial sector. Some materials substitution options, for example the production of lightweight materials for vehicles, can increase GHG emissions from the industrial sector, which will be more than offset by the reduction of emissions from other sectors (See Section 7.4.9). Use of bio-materials is a special case of materials substitution. No projections of the GHG mitigation potential of this option were found in the literature.