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(a) Authors' estimates based on various statistics (rounded).

(b) Throughout this chapter, in keeping with industry standards, quantities are expressed metric tonnes (t) per year.

(c) Ecoinvent 2.0, EMPA/ETH Zurich.

(a) Authors' estimates based on various statistics (rounded).

(b) Throughout this chapter, in keeping with industry standards, quantities are expressed metric tonnes (t) per year.

(c) Ecoinvent 2.0, EMPA/ETH Zurich.

are geologically closely connected to certain major metal deposits, and thus their mine production depends heavily on the host metal. Such by-products or coupled products (for distinction, see discussion below) lead to highly complex demand/supply and price patterns. There are a few examples where minor metals are extracted on their own (e.g., lithium, tantalum), but due to their specific properties and relatively low production volumes, they still are included. Thus, to summarize, the term "minor metals" or "technology metals" is used in this chapter as a synonym for special and precious metals. In no way does the word minor imply a valuation of importance; to the contrary, these metals play a significant role in sustainable technology solutions.

The Significance of Special and Precious Metals for Sustainability

Special and precious metals play a key role in modern industrial technologies as they are of specific importance for clean technologies and other high-tech equipment. Important areas of application are information technology (IT), consumer electronics, as well as materials used in sustainable energy production such as solar cells, wind turbines, fuel cells, and batteries for hybrid cars (see also Rayner, this volume; Loeschl et al., this volume). They are crucial for more efficient energy production (in steam turbines), for lower environmental impact of transport (jet engines, car catalysts, particulate filters, sensors, control electronics), for improved process efficiency (catalysts, heat exchangers), and in medical and pharmaceutical applications. Table 10.2 provides an overview of the main application areas for each metal and illustrates their significance for modern life.

Driving forces for their booming use are their extraordinary and sometimes exclusive properties which make many of these metals essential components in a broad range of applications. For example, the platinum group metals (PGMs: Pt, Pd, Rh, Ru, Ir) have unique catalytic properties and are widely used in car catalysts (Pt, Pd, Rh) as well as in process catalysts (PGMs in various combinations, also with special metals). Moreover, Pt and Ru are essential for fuel cells (PEM, DMFC and PAFC type), in high-density data storage (computer hard disk drives), and in super alloys. Pt and Rh are applied in sensors, thermocouples, manufacturing of LCD glass, technical glass, and glass fibers. Pd is used in dentistry and Pt is used in medical (stents, pacemakers) and pharmaceutical applications. A further use of Pd is in electronics (Multi-Layer Ceramic Capacitors, MLCC), whereas Ru is also used for resistors or plasma displays and may become important for new technologies (e.g., super capacitors, super conductors, dye-sensitized solar cells and OLEDs).

The same applies for special metals (Table 10.2). Indium tin oxide (ITO) forms a conductive transparent layer, which is needed for LCDs as well as for thin film photovoltaics (PV), causing a soaring demand for indium. Its other applications include lead-free solders and low melting point alloys. Tellurium

Table 10.2 Applications in which minor/technology metals are used.
Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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