Critical Raw Materials Substitution Profiles September 2013 Revised May 2015

Critical Raw Materials Substitution Profiles September 2013 Revised May 2015

Authors Luis TERCERO ESPINOZA and Torsten HUMMEN (Fraunhofer Institute for Systems and Innovation Research ISI) Aymeric BRUNOT (CEA - Commissariat à l’Energie Atomique et aux Energies Alternatives) Arjan HOVESTAD (TNO Netherlands Organisation for Applied Scientific Research) Iratxe PEÑA GARAY and Daniela VELTE (Tecnalia) Lena SMUK and Jelena TODOROVIC (SP Sveriges Tekniska Forskningsinstitut AB) Casper VAN DER EIJK (SINTEF) Catherine JOCE (Chemistry Innovation)

Contact Dr. Luis A. TERCERO ESPINOZA Coordinator of Business Unit Systemic Risks Competence Center Sustainability and Infrastructure Systems Fraunhofer Institute for Systems and Innovation Research ISI Breslauer Str. 48, D-76139 Karlsruhe [email protected], Tel. +49 721 6809-401 Reproduction is authorised provided the source is acknowledged. This document is available on the internet at: http://cdn.awsripple.com/www.criticalrawmaterials.eu/ uploads/D3.3-Raw-Materials-Profiles1.pdf

This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement No 319024.

What is CRM_InnoNet? The Innovation Network for Substitution of Critical Raw Materials (CRM_InnoNet) is a collaborative project facilitating networking and delivering European roadmaps on the topic of substitution of critical raw materials.

What is substitution? Substitution is one strategy that can reduce the reliance of a company, sector or economy on imported critical raw materials. Other strategies include increased recycling or primary extraction. CRM_InnoNet is exploring where the strategy of substitution has the best economic and technological potential for European industry. There are four main substitution strategies:

The Critical Raw Materials Substitution Profiles In order to understand the opportunities and challenges presented by critical raw materials, and the areas where substitution could offer a solution, it was important to look at each individually. This report, the Critical Raw Materials Substitution Profiles, is a compilation of detailed profiles on each of the 14 materials identified as critical by the European Commission in 2010. Each raw material profile provides a detailed analysis of the end uses of the material and goes on to examine where there are already substitution options or where alternatives might be easily developed. Development of the Critical Raw Materials Substitution Report was led by the Fraunhofer Institute for Systems and Innovation Research, in collaboration with CRM_InnoNet project partners.

Further reading CRM_InnoNet has also completed detailed supply chain analysis of applications in the ICT and electronics, energy and transport sectors. These reports can be downloaded from the website: http://www.criticalrawmaterials.eu/documents/ To join the Network or to find out more, please get in touch; www.criticalrawmaterials.eu Twitter @CRM_InnoNet [email protected]

Document description This document includes substitution profiles for each of the 14 raw materials identified as critical for the EU in 2010. These are:              

Antimony Beryllium Cobalt Fluorspar Gallium Germanium Graphite Indium Magnesium Niobium Platinum Group Metals Rare Earth Elements Tantalum Tungsten

Each profile includes a description of supply, main uses and an assessment of current substitution possibilities for each of the CRM in a way that is compatible with the work of the Ad-hoc Working Group on defining Critical Raw Materials. Compared to the original version (September 2013), this document includes (limited) changes to the technical parts of the profiles for fluorspar, magnesium, rare earths, tungsten, and beryllium as well as to the market part of the indium profile. These changes arise from feedback from the public delivered between September 2013 and February 2015.

1. Antimony Antimony is a semimetal, which can usually be found in its most stable metallic form. In its metallic form it is physically bright, silvery, with a metallic lustre and average hardness and brittleness. Antimony is a poor conductor of heat and electricity. Antimony and many of its compounds are toxic.1 Antimony is mined both as a main metal and as a by-product: The main antimony ore is antimony sulfide (stibnite), but lead and copper ores often contain antimony, which is concentrated as a by-product and obtained during the recovery of the main metal. Antimony is recovered in its metallic form from ore primarily through pyrometallurgical techniques.2,3 The production of antimony is currently concentrated mainly in China and the average price of antimony metal was about 3US$/kg in 2011* (see also Figure 2).4 After a peak in 2011, the price has been generally decreasing over recent years.5

Figure 1: Distribution of antimony production6 and corresponding scores of the producing countries in the Human Development Index (HDI),7 Environmental Performance Index (EPI),8 and World Governance Indicators (WGI).9 Both the EPI and WGI are used to assess supply risks with the EU methodology for determining critical raw materials.10 CHN = China.

*

New York dealer price for 99.5% to 99.6% metal, c.i.f. U.S. ports.

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Unit value (1000 USD/t)

14 12 10 8

6 4 2 0 1980

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Year Figure 2: Antimony price development during 1980 – 2011. The unit value of antimony reports the value of 1 metric ton (t) of antimony apparent consumption (estimated).11

Uses and Substitutability Flame retardants With a share of 71% of antimony consumption, antimony as antimony trioxide is mainly used for flame retardants. The main applications within this sector include polyvinylchloride (PVC) for conveyor belts for example in mines, cable coatings; coated fabrics for wall coverings and cushion covers, among others. Moreover, it is used as high impact polystyrenes for television backs and domestic electrical appliances, as well as housings for electrical equipment (including PCs). Polyethylene and propylene is primarily used for wire sheathing and electrical conduits in buildings. Polyamides and engineering plastics such as nylons for automotive uses, industrial equipment, and electric moulded parts as well as unsaturated polyesters for applications such as building panels, automotive parts, and lifeboat hulls are further typical uses of antimony.2 When antimony trioxide is combined with a halogen, flame retardant properties are imparted to several materials through the formation of halides. Antimony halides promote reactions that cause the formation of carbonaceous char rather than volatile gases. This char then acts as a heat shield that retards the breakdown of the plastics, thus preventing the release of flammable gases.2 Antimony trioxide can be substituted with selected organic compounds, hydrated aluminum oxide or mixtures of zinc oxide and boric oxide.4,12 However, while substitutes are available, in general, antimony is seen to offer superior performance.

Lead alloys2 The second largest application for antimony is in lead alloys, making up a market share of 9%. Due to its weak mechanical properties, it is mainly used in numerous alloys with lead and tin. The final use of the

alloy is determined by both the percentage of antimony in the alloy as well as the other compounds present. For antimonial, or hard, lead alloys containing antimony between 1-15%, the presence of antimony results in an increase of tensile strength, rendering the material more robust to stresses enforced by charging and discharging reactions. Antimonial lead alloys that contain 1-9% of antimony are used for cable sheathing and lead pipes, whereas the same alloys with 7-12% antimony are used for storage batteries and with an antimony content of 12-15% they are used for small-arms ammunition. Antimonial lead alloys with an antimony content between 1.5-3% are mainly applied for grid plates, straps, and terminals of lead-acid batteries. Here, the addition of antimony improves fluidity, making the casting of battery grids easier. Tensile strength is also increased, as is the electrochemical stability of lead. Babitt metals include both ternary tin-antimony-copper alloys and quaternary tin-antimony-copper-lead alloys, in both cases with a share of antimony ranging between 4.5-14%. Babitt metals are applied in low load bearings. The addition of antimony to the alloy results in good anti-seizure properties and corrosion resistance on the one side but low fatigue strength on the other side. Heavy load bearings, which require a higher fatigue resistance for applications such as railways, use quaternary tin-antimony-copper-lead alloys with an antimony share between 8 and 15%. Type metals are antimony-lead alloys containing 2.5 – 25 % antimony. These alloys are used in the printing industry and the antimony is added in order to lower the casting temperature, increase the hardness and minimize shrinkage during freezing. Brittania Metal and Pewter contain 7 - 20% antimony which increases the hardness of the metal and allows a highly polished surface to be obtained. These metals are used for the manufacture of vases, lamps, candlesticks, tea and coffee services, and other decorative applications. Tin-lead alloys with an antimony share of less than 1% are used for soldering, whereby the antimony increases the hardness of the alloy. Antimionide contains, in addition to antimony, indium, aluminum and gallium. Antimony is added due to its electrochemical properties as the applications include dopants in semiconductors for infrared detectors, Hall-effect devices and diodes. In general, combinations of cadmium, calcium, copper, selenium, strontium, sulfur and tin can substitute antimony in most lead alloys.4

Rubber For the vulcanization of red rubber compounds, a 7% share of antimony is utilized. Antimony pentasulfide, Sb2S5, adds the required flexibility.2 It is difficult to substitute.13

Glass The glass industry represents a 5% share of antimony use in the form of sodium hexahydroxyantimonate. This compound is prepared by melting antimony or antimony oxides with excess sodium nitrate and is used as an opacifier for glass and enamels.2 Glass containing antimony trioxide or sodium antimonate is used for television tubes, as the oxide removes color and gas bubbles. Substitutes include compounds of chromium, tin, titanium, zinc and zirconium.4 Therefore, it is comparatively easy to substitute.13

Catalysts Catalysts make up 4% of antimony use, mostly for the polymerization catalyst in the manufacture of polyester fibres, which requires antimony trioxide.2 A potential substitute is titanium catalysts, which can be inactivated when a dulling agent is applied. There are some concerns around heavy metals in plastics leaching e.g. into drinking water. However, titanium catalysts are not expected to replace antimony in PET production to a significant extent with 2020 as a time horizon (even though alternatives exist at the R&D stage) as there is no regulatory pressure from the FDA or the EC. Therefore antimony is assumed to be currently difficult to replace.14

Pigments & Others2 Pigments and other applications for antimony result in a 4% antimony use. Chromate pigments apply antimony trioxide for its unique pigmentation properties. However, compounds of chromium, tin, titanium, zinc and zirconium could be used as substitutes.4 Another use for antimony is as an opacifier for ceramic glazes and as a frit. Antimony trioxide is used in these applications as well. Antimony is comparatively easy to substitute in its use for pigments.13

Summary The demand for antimony is dominated by its use in flame retardants (as antimony trioxide). Because the applications—and requirements—vary widely, there are options for substituting antimony trioxide partially or, in some cases, completely. Also, substitutes are available for its use in lead alloys, glass & pigments, apparently with limited loss of performance or additional costs. This is not the case for rubber and catalysts, where the use of antimony brings substantial advantages in either performance or costs.

Figure 3: Distribution of end-uses and corresponding substitutability assessment for antimony. The manner and scaling of the assessment is compatible with the work of the Ad-hoc Working Group on Defining Critical Raw Materials (2010).

References 1 2

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Haynes WM (ed.) (2012) CRC Handbook of Chemistry and Physics, 93rd edn.: Taylor & Francis Grund, S. C., Hanusch, K., Breunig, H. J., Wolf, H. U. (2006) Antimony and Antimony Compounds, in: Ullmann's Encyclopedia of Industrial Chemistry, pp. 11–42. Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA Butterman W.C., Carlin JF, JR. (2004) Antimony. Open-File Report 03-019 Carlin, J. F., JR. (2013) Antimony, in: U.S. Geological Survey (ed.) Mineral commodity summaries 2013, pp. 19–20 Metal Bulletin Antimony MB free market in warehouse $ per tonne monthly average: Latest Metal Prices Tracking and Comparison Tool. http://www.metalbulletin.com/My-price-book.html?price=34138. Accessed 3 September 2013 Reichl C, Schatz M, Zsak G (2013) World Mining Data: Production of Mineral Raw Materials of individual Countries, by Minerals. in 2011 in metric tonnes United Nations Development Programme (UNDP) (2013) The 2013 Human Development Report – "The Rise of the South: Human Progress in a Diverse World" Yale Center for Environmental Law and Policy (YCELP) (2013) Downloads | Environmental Performance Index. http://epi.yale.edu/downloads. Accessed 26 July 2013 World Bank Group (2013) Worldwide Governance Indicators. http://info.worldbank.org/governance/wgi/sc_country.asp. Accessed 26 July 2013 Ad-hoc Working Group on defining critical raw materials (2010) Critical raw materials for the EU: European Commission Buckingham, D., Carlin, J., JR. (2012) Antimony: Supply-Demand Statistics, in: U.S. Geological Survey Minerals Information Borax Firebrake ZB: An unique zinc borate combining the optimum effects of zinc and boron oxides and water release for developing fire retardant formulations processable up to 290 °C. http://www.borax.com/product/firebrake-zb.aspx. Accessed 28 August 2013 Eurometaux (2013) Antimony Substitutability. personal notification Joce C (2013) Antimony Substitutability. personal notification

2. Beryllium Beryllium has been commercially available since the 1920’s, when it was used to improve the mechanical properties of copper alloys. This is the main use still today, leading to some of the strongest copper-based alloys which, at the same time, retain a high electrical conductivity. Pure beryllium exhibits a low density coupled to a high modulus of elasticity (resulting in a remarkably high specific strength), one of the highest melting points of the light metals and a high conductivity for electricity and heat. It also reflects IR, transmits X-rays well, absorbs neutrons, and resists attacks by concentrated nitric acid. Furthermore, it resists oxidation in air at temperatures up to 600 °C. However, a high price, its toxic effects on the lungs if inhaled (requiring strict preventive measures in manufacturing), and the room-temperature susceptibility to brittle fracture of the metal are drawbacks of beryllium.1–3 Beryllium is mainly (≈ 95%) produced from ores containing 0.3% – 1.5% beryllium. In addition, it can be obtained in small quantities as a by-product (beryl) of emerald extraction.4 The largest producer of beryllium worldwide is the USA.5

Figure 1: Distribution of beryllium production5 and corresponding scores of the producing countries in the Human Development Index (HDI) 6, Environmental Performance Index (EPI) 7, and World Governance Indicators (WGI).8 Both the EPI and WGI are used to assess supply risks with the EU methodology for determining critical raw materials.9 USA = United States of America; CHN = China. Beryllium is one of the most expensive raw materials. Its price increased over the last few years up to approximately 93 US$/kg in 2011 and is recovering from a peak (104 US$/kg) in 2010. *5

*

Unit value, annual average, beryllium-copper master alloy, dollars per kg contained beryllium: Calculat ed from gross weight and customs value of imports; beryllium content estimated to be 4%.

Unit value (1000 USD/t)

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Figure 2: Beryllium price development during 1980 – 2011. The unit value is defined as the value of 1 metric ton (t) of beryllium apparent consumption (estimated).10

Uses and substitutability Mechanical Equipment With a share of 25%, the manufacture of mechanical equipment represents a key use of beryllium. Beryllium is mainly used alloyed in small amounts with copper and nickel to improve their ability to conduct electricity and heat, coupled with high strength and machinability and formability. 11 The combination of strength and ductility is controlled by both cold work and age hardening of the alloys. The main applications of these alloys are conductive spring terminals of high reliability electrical and electronic connectors (see below), drilling and mineral mining equipment, undersea housings of fiber optic cables, metal and plastic casting moulds, springs as well as electrode holders and components of welding robots .12,13 Since beryllium is only utilized in applications in which its properties are crucial, it is hard to substitute in general.3 Nevertheless, if it is used exclusively due to its mechanical properties, beryllium can be substituted with titanium, magnesium, aluminium and their alloys or with carbon fiber composites. If only a thermal improvement is required, beryllium can be substituted with aluminium metal matrix composites with added silicon carbide / boron nitride.1 3 However, there are no currently available materials that exhitbit these properties in combination.14

Electronics & ICT The electronics & ICT sector accounts for 20% of European beryllium end-use, virtually all of which is used in the form of copper-beryllium alloys for durable and reliable conductive spring terminals of electrical and electronic connectors in computers, mobile phone handsets and infrastructure equipment, power amplifiers and civil aviation radar systems. Additionally, copper beryllium alloys are used for electrical spring contacts in switches and relays of electronic and telecommunications equipment. 3,11,13,15

If used solely for its mechanical properties, copper alloys containing beryllium can be substituted by other alloys such as phosphor bronze or copper silicon, but at the—for electronics and ICT unacceptable—cost of electrical conductivity.14 Reducing or eliminating beryllium from the copper alloys leads to decreased reliability and longevity of the components. The ceramic form, BeO, beryllium oxide or beryllia, has an unusual combination of properties, the most important of which are its high electrical insulation, coupled with a hardness only slightly lower than that of diamond, and thermal conductivity an order of magnitude greater than that of alumina. Its low dielectric constant and low loss index promote its use as an electronics circuit substrate with extremely good performance at high frequencies. Only a small quantity of beryllium is used in beryllium oxide ceramic components used in applications such as high power RF amplifiers, IC and other electronic chip substrates for high power radar systems.3,14 For some of the less demanding electronic packaging thermal management applications, beryllium oxide ceramic has been substituted for with silicon carbide / boron nitride aluminium metal matrix composites but with reduced efficiency and loss of electrical insulation. 5,16 No adequate substitute has been found for more demanding applications such as medical excimer laser bore tubes and high power RF travelling wave tube amplifiers and RF amplifiers.14,16

Electrical equipment & domestic appliances The electrical equipment & domestic appliances sector has a share of 20% and uses copper beryllium and nickel beryllium because of the properties outlined above. Typical applications include: Switches, thermostat controls and relays, electrical and electronic connectors used in appliances, fire sprinkler water control springs, pressure gauges and many other conductive spring applications. In household applianace temperature and other function controls as well as in relays, beryllium may be substituted (with loss of performance) by the use of nickel and silicon, tin, titanium, or other alloying elements or phosphor bronze alloys. It is reported that in numerous cases, earlier replacements of beryllium with lesser performing alloys has lead to (unacceptably) shorter product lifetimes such that copper beryllium alloys have been reintroduced to restore performance.2,16

Road transport The road transport sector, which has a share of 15% in European beryllium end-use, mainly uses beryllium copper alloys in electrical and electronic connectors for high reliability automobile applications such as airbag crash sensors, anti-lock brake systems, traction control and all engine sensors, navigation and entertainment systems and in the form of aluminium beryllium master alloys containing 1-5% beryllium, as a metallurgical structure modifier and magnesium addition conditioner for aluminium and magnesium alloys and castings.3,16 Purpose and substitutability of beryllium is as outlined above. However, the loss of performance upon substitution is generally unacceptable in safety-related applications.

Aerospace13 A 13% share of total beryllium consumption goes to use in alloys for aircrafts, mainly because of its mechanical properties, particularly the specific strength and stiffness of the metallic beryllium form for structural applications (especially at extremely low temperatures), and the unique combination of strength, conductivity, low friction and machinability of the copper beryllium alloy form. Copper-beryllium is used for low friction applications such as in aircraft landing gear bearings, for rod-end bushings and no-fail emergency door fasteners, and for its thermal conductivity in pitot tube castings. Possible substitutes are copper alloys containing nickel and silicon, tin, titanium, or other alloying elements or phosphor bronze alloys (copper-tin-phosphorus), steel or titanium. However, there are no substitute alloys that provide the

same combination of properties or long term reliability, which is generally unacceptable in safety-related aerospace components.5,13,14,16 Another major application for copper beryllium alloys in aerospace is as the female connector terminals in electronic and electrical connectors (thousands of connectors per aircraft), which are subject to intense vibration and stresses, yet must perform reliably over the 30 – 40 year lifespan of an aircraft. Theoretically, copper alloys containing nickel and silicon, tin, or titanium, or phosphor bronze alloys are alternatives. In practice, however, there is a loss of performance that is inadmissible in safetyrelated applications.16 Beryllium metal is used for example in gyroscope gimbals and yokes for use in guidance, navigational and targeting systems for helicopters and aircraft, as well as in satellite mounted directional control systems. For individual mechanical properties, the metallic beryllium used in aerospace applications could be substituted for by certain metal matrix or organic composites, high-strength alloys of aluminium, magnesium, steel, or titanium. However, no other material offers the specific stiffness and strength combination that beryllium does, making it irreplaceable in practice.2,16,17

Others Other final consumer goods make up 7% beryllium consumption due to the fact that it is relatively transparent to X-rays. Copper beryllium is used in medical isotope production nuclear reactors; fire sprinkler water control valve springs and X-ray lithography for the reproduction of micro-miniature integrated circuits. Furthermore it is used in X-Ray transparent windows, and mirrors for terrestrial and space mounted astronomical telescopes. Beryllium oxide is necessary in ceramic applications, medical excimer laser beam focusing and its control components.13

Summary Beryllium, being a very expensive metal, tends to be used only where its properties are needed and no reasonable substitute can deliver the desired result. In particular in safety related applications (e.g. anti-lock brake systems in cars, some aerospace), reduced performance/durability is unacceptable.

Figure 3: Distribution of end-uses 18 and corresponding substitutability assessment for beryllium. The manner and scaling of the assessment is compatible with the work of the Ad-hoc Working Group on Defining Critical Raw Materials (2010).

References 1 2

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5 6 7 8 9 10 11 12 13 14 15

16 17

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BesT - Beryllium Science & Technology Association (2015) Safety Model. http://beryllium.eu/workingsafely-with-beryllium/protecting-workers/safety-model/. Accessed 29 May 2015 BesT - Beryllium Science & Technology Association (2013) Critical Applications of Beryllium. http://beryllium.eu/about-beryllium-and-beryllium-alloys/critical-applications-of-beryllium/. Accessed 29 May 2015 Svilar, M., Schuster, G., Civic, T., Sabey, P., Vidal, E., Freeman, S., Petzow, G., Aldinger, F., Jönsson, S., Welge, P., Kampen, V., Mensing, T., Brüning, T. (2013) Beryllium and Beryllium Compounds, in: Ullmann's Encyclopedia of Industrial Chemistry, pp. 1–35. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA BesT - Beryllium Science & Technology Association (2013) Beryllium Extraction. http://beryllium.eu/about-beryllium-and-beryllium-alloys/facts-and-figures/beryllium-extraction/. Accessed 15 May 2013 Jaskula, B. W. (2013) Beryllium, in: U.S. Geological Survey (ed.) Mineral Commodity Summaries 2013, pp. 28–29 United Nations Development Programme (UNDP) (2013) The 2013 Human Development Report – "The Rise of the South: Human Progress in a Diverse World" Yale Center for Environmental Law and Policy (YCELP) (2013) Downloads | Environmental Performance Index. http://epi.yale.edu/downloads. Accessed 26 July 2013 World Bank Group (2013) Worldwide Governance Indicators. http://info.worldbank.org/governance/wgi/sc_country.asp. Accessed 26 July 2013 Ad-hoc Working Group on defining critical raw materials (2010) Critical raw materials for the EU: European Commission Buckingham, D., Cunningham, L., Shedd, K., Jaskula, B. (2012) Beryllium: Supply-Demand Statistics, in: U.S. Geological Survey (ed.) Minerals Information Royal Society of Chemistry (2013) Beryllium. http://www.rsc.org/periodic-table/element/4/beryllium. Accessed 15 May 2013 Chemicool.com (2013) Beryllium. http://www.chemicool.com/elements/beryllium.html. Accessed 15 May 2013 BesT - Beryllium Science & Technology Association (2013) Substitutes for beryllium and alloys containing beryllium. Email BesT - Beryllium Science & Technology Association (2015) Alternate Materials. http://beryllium.eu/about-beryllium-and-beryllium-alloys/alternate-materials/. Accessed 29 May 2015 BesT - Beryllium Science & Technology Association (2013) Uses & Applications of Beryllium. http://beryllium.eu/about-beryllium-and-beryllium-alloys/uses-and-applications-of-beryllium/. Accessed 15 May 2013 BesT - Beryllium Science & Technology Association (2015) Substitution of beryllium. E-Mail BesT - Beryllium Science & Technology Association (2015) Uses of Beryllium. http://beryllium.eu/about-beryllium-and-beryllium-alloys/uses-and-applications-of-beryllium/. Accessed 29 May 2015 Materion (2013) Investor Presentation. http://files.shareholder.com/downloads/BW/2469474044x0x659351/73c733fd%E2%80%90043d%E2% 80%904959%E2%80%90972de68ddb89fcd4/Investor_Presentation_May_2013.pdf. Accessed 15 May 2015

3. Cobalt Cobalt is shiny, grey, brittle metal with a close packed hexagonal (CPH) crystal structure at room temperature but which changes at 421 °C to a face centred cubic form. It has a high melting point (1493 °C) and boiling point (3100 ºC) and it maintains its strength and integrity at extremely high temperatures. In addition, cobalt, as well as nickel and iron, is ferromagnetic and retains this property up to 1100 °C, a higher temperature (Curie point) than any other material. Hence, one of its key uses is in magnets for hightemperature applications. Cobalt is rarely used as a structural material in its pure form but rather is employed as an alloying element. The first use of cobalt was as a pigment in conjunction with silica to produce intense blue colours. This remained as the main use of cobalt until the 20th century. However, cobalt is a very versatile metal and over the 20th century it started to be employed for a wide array of applications such as metallurgical uses (e.g. superalloys), magnets, batteries, pigments, catalysts, etc. In addition to its industrial uses and relevance, cobalt is one of the around 20 elements which are essential to humans. Cobalt is contained in vitamin B12, which is important in protein formation and DNA regulation. Cobalt is recovered both as a main metal from dedicated cobalt mines (minor source) and as a by-product (major source), especially of nickel and copper mining.1,2 It is only extracted alone from Moroccan and Canadian arsenide ores. The main producer of cobalt worldwide is the Democratic Republic of Congo. Historical price data are shown in Figure 2. The average price in 2011 was 8.18 US$/kg*.3 When looking at the price of cobalt in more detail, the large scale fluctuation seen in Figure 2 continues. The price decreased in the beginning of 2013, rose up in the middle of the year and felt down after this peak recently.4

Figure 1: Distribution of cobalt production5 and corresponding scores of the producing countries in the Human Development Index (HDI)6, Environmental Performance Index (EPI)7, and World Governance *

Spot, cathode: As reported by Platts Metals Week

Indicators (WGI)8. Both the EPI and WGI are used to assess supply risks with the EU methodology for determining critical raw materials 9. COD = D. R. Congo; CAN = Canada; CHN = China. 80

Unit value (1000 USD/t)

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Year Figure 2: Cobalt price development during 1980 – 2011. The unit value is defined as the value of 1 t of cobalt apparent consumption (estimated).10.

Uses and substitutability Batteries The increase in demand for portable electronic devices since the 1980s boosted the demand for high capacity rechargeable batteries. In this context, rechargeable batteries containing cobalt display a high energy density, along with the capability of quick charging and low stand-by energy losses. For this reason, one of the preferred uses of cobalt is in batteries of portable devices, such as cell phones, laptops, smartphones, tablets, etc. Lithium-ion (Li-ion) batteries containing cobalt-based cathodes contain the most cobalt with a market share of 30%, but nickel metal hydride (Ni-MH) and nickel cadmium (NiCd) batteries also use cobalt. Overall, close to 30% of cobalt demand is attributed to its use in batteries. A continued increase in demand for Li-ion is expected in the electronics sectors correlating to the surge in demand for portable devices (especially telephones) in emerging economies. Moreover, emerging use of cobalt in some rechargeable batteries for electric vehicle applications is expected to increase cobalt demand over the next ten years. Substitution of cobalt in Li-Ion batteries is potentially possible. Although LiCoO2 is the preferred material for portable battery applications11, both LiNiO2 and LiMn2O4 can also be used for the same purpose. In addition, latest industry predictions indicate that many of the disadvantages of alternative materials have been overcome and although rechargeable battery demand is expected to increase rapidly in the next few years, cobalt demand in this application could remain stable or even decrease slightly.

In addition, the recycling and recovery rates of cobalt from end-of-life batteries are promising. Recent research 12,13 shows that new recycling strategies are being implemented to increase the recovery valuable materials, especially cobalt, from batteries. In this regard, it should be noted that high recycling rates of end-of-life cobalt are reported14. Finally, it is worth mentioning the industrial scale end of life rechargeable batteries recycling facility set up by Umicore in Belgium in 201115.

Superalloys and magnets Cobalt-based super-alloys are one of the largest markets for cobalt 16. They have their origins in the Stellite alloys patented in the early 1990’s by Elwood Haynes. Cobalt-based super-alloys have higher melting points than nickel-based ones and retain their strength at higher temperatures. They also show superior weldability, hot corrosion and thermal fatigue resistance than nickel-based alloys.17 These properties make them suitable for use in turbine blades for gas turbines and jet aircraft engines.18 Fiber-reinforced metal matrix composites (MMC), ceramic-ceramic and carbon-carbon composites, titanium aluminides, nickel-based single crystal alloys or iron-based super-alloys may substitute cobalt-based ones in these applications to some extent. Loss of performance at high temperatures (due to the unique physical properties of Co) can, however, be expected in some cases.19 Therefore, substitution for cobalt in jet engine castings will probably not occur and cannot be considered as a meaningful solution to the cobalt supply problem. Cobalt is also used in samarium-cobalt and aluminium-nickel-cobalt permanent magnets. These are widely used in electric motors, electric guitar pickups, microphones, sensors, loudspeakers, traveling-wave tubes, and cow magnets.20 They have comparable strength but much higher temperature ratings and higher coercivity than neodymium magnets.21 There is some potential for substitution of cobalt-alloyed magnets by nickel-iron or neodymium-iron-boron ones. The substitution seems to be difficult though in high temperature applications since cobalt-alloyed magnets have significantly higher Curie temperatures and are the only magnets that have useful magnetism even when heated red-hot.22

Hard metal and surface treatment Around 12% of the final cobalt consumed is destined to hard metal and surface treatment. Cobalt is used in cemented carbides as a binder phase. The carbides are usually Tungsten-Carbides although sometimes also Titanium-Carbo-Nitrides or Tantalum-Carbides are used. The binder phase is typically between 5 and 30 vol% of the component. The more hard carbide particles are within the material, the harder it is but the less tough it behaves during loading; and, vice versa, significant increases in toughness are achieved by a higher amount of metallic binder at the expense of hardness. The high solubility of tungsten carbide (WC) in the solid and liquid cobalt binder at high temperatures provides a very good wetting of WC and results in an excellent densification during liquid phase sintering and in a pore-free structure.23 There is potential for substitution of cobalt-iron-copper or iron-copper in diamond tools. Research and development in this field is very active and most of the competing matrix materials have a lower cost.24–26 However, there is a certain loss of performance.

Pigments Pigments account for 9% of cobalt use. The unique colouring properties of cobalt produce light blue to black pigmentation for ceramics, glass, porcelain, enamel, paint and inks 2, whereby the amount of cobalt

oxide added to the final product depends on the required colour. As cobalt(II) acetate it is used in the production of drying agents for inks and pigments. Cerium, iron, lead, manganese, and vanadium can all be used as substitutes for cobalt for this application, unfortunately not necessarily with the same results.3

Catalysts Cobalt is widely used in the oil and gas sector. It is used in hydrodesulfurization (a catalytic chemical process widely used to remove sulfur from natural gas and from refined petroleum products such as gasoline or petrol), where the catalyst must be sulfur resistant. 27 Catalysts account for 6% of cobalt use. Cobalt catalysts also play an important role bulk chemical production of PTA (a monomeric precursor to polyester) and a process called hydroformylation which generates aldehydes and alcohols used in the plastics and detergent markets.27 In addition, it is also used in the catalysis of gas to liquid processes. expected to result in a major new demand for cobalt. 29

28

The application of this technology is

Finally, a potential emerging use (and subsequent increase in demand) of cobalt is as catalyst in hydrogen fuel cells.30 With regard to its application for hydrodesulfurization, ruthenium, molybdenum, nickel and tungsten can be used depending on nature of the feed, instead of cobalt.3,31–33 Also alternative ultrasonic process can dispense with the use of cobalt, and rhodium can serve as a substitute for hydroformylation catalysts.3

Others There is still a remaining 8% of cobalt that is used for various other applications. Cobalt powders are used for their high melting point, high-temperature strength and for the fact that they can be produced as a very fine powder in binders for the diamond tool industry. For this application, cobalt can be substituted by cobalt-iron-copper or iron-copper.1 Cobalt salts are used in agriculture as a supplement to animal feeds, as cobalt is an essential element in the human and animal metabolism.2 The cobalt isotope Co60 is a strong gamma-ray emitter, which is used in the medical field for radiation therapy. Other medical applications for cobalt include the use of cobalt-chromium alloys for cast denture bases, complex partial dentures, and some types of bridgework for dental applications due to cobalt’s high strength and tension properties. The good castability, resistance to tarnish, compatibility with mouth tissues, high strength and stiffness, and low density makes cobalt suitable for these applications. Similar cobalt-chromium alloys are also used for surgical implants and bone replacement (e.g. hip joint replacement) and repair because of cobalt’s resistance to corrosion and high fatigue strength of the cobaltchromium-alloy.1 Other applications include the manufacture of Elgiloy, a spring alloy containing 40% cobalt, 20% chromium, 15% nickel, 7% molybdenum, and 2% manganese, alloys composed of cobalt-nickel or cobalt-ironmagnesium-carbon used as magnetic recording materials and cobalt silicate, which is applied for electrical connectors and integrated circuits. A material with a very low coefficient of thermal expansion results from alloying cobalt in low-expansion iron–nickel alloys of the Invar type.1

Summary Substitution of cobalt in Li-Ion batteries—the single largest application—is possible, although this is not the preferred option. Moreover, in this field, recycling and recovery hold some promising potential. Similarly, substitution comes at the expense of performance due to the unique properties of cobalt in superalloys, magnets, hard metals and surface treatment. Cobalt substitution in pigments by acetate, cerium, iron, etc. is possible but also leads to a decrease in performance. Finally, cobalt as a catalyst may be substituted to some extent for hydrodesulfurization and hydroformylation proceses.

Figure 3: Distribution of end-uses and corresponding substitutability assessment for cobalt. The manner and scaling of the assessment is compatible with the work of the Ad-hoc Working Group on Defining Critical Raw Materials (2010).

References 1 2 3 4 5 6 7 8 9 10 11 12

13

14 15 16 17 18 19

20 21 22

23

Donaldson, J. D., Beyersmann, D. (2010) Cobalt and Cobalt Compounds, in: Ullmann's Encyclopedia of Industrial Chemistry, pp. 429–465. Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA Hannis, S., Bide, T. (2009) Cobalt, in: British Geological Survey (ed.) Commodity Profiles Shedd, K. B. (2013) Cobalt, in: U.S. Geological Survey (ed.) Mineral commodity summaries 2013, pp. 46–47 Metal-Pages Cobalt metal prices, news and information. http://www.metalpages.com/metals/cobalt/metal-prices-news-information/. Accessed 3 September 2013 Reichl C, Schatz M, Zsak G (2013) World Mining Data: Production of Mineral Raw Materials of individual Countries, by Minerals. in 2011 in metric tonnes United Nations Development Programme (UNDP) (2013) The 2013 Human Development Report – "The Rise of the South: Human Progress in a Diverse World" Yale Center for Environmental Law and Policy (YCELP) (2013) Downloads | Environmental Performance Index. http://epi.yale.edu/downloads. Accessed 26 July 2013 World Bank Group (2013) Worldwide Governance Indicators. http://info.worldbank.org/governance/wgi/sc_country.asp. Accessed 26 July 2013 Ad-hoc Working Group on defining critical raw materials (2010) Critical raw materials for the EU: European Commission Buckingham, D., Shedd, K. (2012) Cobalt: Supply-Demand Statistics, in: U.S. Geological Survey Minerals Information Cobalt Development Institute (2013) Cobalt Development Institute. http://www.thecdi.com/. Accessed 8 August 2013 Jha, A. K., Jha, M. K., Kumari, A., Sahu, S. K., Kumar, V., Pandey, B. D. (2013) Selective separation and recovery of cobalt from leach liquor of discarded Li-ion batteries using thiophosphinic extractant. Separation and Purification Technology 104, 160–166. 10.1016/j.seppur.2012.11.024 Iizuka, A., Yamashita, Y., Nagasawa, H., Yamasaki, A., Yanagisawa, Y. (2013) Separation of lithium and cobalt from waste lithium-ion batteries via bipolar membrane electrodialysis coupled with chelation. Separation and Purification Technology 113, 33–41. 10.1016/j.seppur.2013.04.014 United Nations Environment Programme (UNEP) (2012) Metal stocks and recycling rates. http://www.unep.org/resourcepanel/Portals/24102/PDFs/Metals_Recycling_Rates_Summary.pdf Umicore (2013) Battery Recycling. http://www.batteryrecycling.umicore.com/UBR/. Accessed 7 August 2013 Cobalt Development Institute (2011) Cobalt News. http://www.thecdi.com/cdi/images/news_pdf/cobalt_news_jan2011.pdf. Accessed 8 August 2013 Materialrulz (2010) Superalloys. http://materialrulz.weebly.com/uploads/7/9/5/1/795167/superalloys.pdf. Accessed 8 August 2013 Office of Technology Assessment (1985) Strategic Materials: Technologies to Reduce U.S. Import Vulnerability. Washington,DC: U.S. Congress Cobalt Development Institute (2006) Cobalt Facts: Metallurgical uses. http://www.thecdi.com/cdi/images/documents/facts/COBALT_FACTS-Metallurgical_%20uses.pdf. Accessed 8 August 2013 Chemicool.com (2013) Cobalt. http://www.chemicool.com/elements/cobalt.html. Accessed 8 August 2013 Cobalt Development Institute (2013) Magnetic Alloys. http://www.thecdi.com/general.php?r=U6ENJWAVAL. Accessed 9 August 2013 Cobalt Development Institute (2006) Cobalt facts: Magnetic Alloys. http://www.thecdi.com/cdi/images/documents/facts/COBALT_FACTS-Magnetic_Alloys.pdf. Accessed 9 August 2013 Davis JR (1993) Properties and selection: Nonferrous alloys and special-purpose materials, 10th edn. Metals Park, Ohio: American Society for Metals

24 Subramanian, R., Schneibel, J. H. (1998) FeAl–TiC and FeAl–WC composites—melt infiltration processing, microstructure and mechanical properties. Materials Science and Engineering: A 244(1), 103–112. 10.1016/S0921-5093(97)00833-2 25 Mosbah, A. Y., Wexler, D., Calka, A. (2005) Abrasive wear of WC–FeAl composites. Wear 258(9), 1337–1341. 10.1016/j.wear.2004.09.061 26 Yusoff, M., Othman, R., Hussain, Z. (2011) Mechanical alloying and sintering of nanostructured tungsten carbide-reinforced copper composite and its characterization. Materials & Design 32(6), 3293–3298. 10.1016/j.matdes.2011.02.025 27 Cobalt Development Institute (2013) Catalysts. http://www.thecdi.com/general.php?r=12ENJWIVAD. Accessed 19 July 2013 28 Umicore (2013) Catalysts Production & Recycling. http://csm.umicore.com/applications/catalysts/. Accessed 19 July 2013 29 Idaho Cobalt (2013) Cobalt Uses. http://www.idahocobalt.com/s/CobaltUses.asp. Accessed 19 July 2013 30 Guo, S., Zhang, S., Wu, L., Sun, S. (2012) Co/CoO Nanoparticles Assembled on Graphene for Electrochemical Reduction of Oxygen. Angewandte Chemie International Edition 47(51), 11770–11773 31 Hielscher Ultrasonics - Ultrasound Technology (2012) Ultrasonic Alternative to Hydrodesulfurization. http://www.hielscher.com/ultrasonics/oil_desulfurization_01.htm. Accessed 19 July 2013 32 The Encyclopedia of Earth (2013) Hydrodesulfurization. http://www.eoearth.org/view/article/171121/#gen2. Accessed 19 July 2013 33 Chen X, Liang C (2012) Nickel silicides: an alternative and high sulfur resistant catalyst for hydrodesulfurization. http://events.dechema.de/Tagungen/Materials+for+Energy+_+EnMat+II/Congress+Planer/Datei_Handl er-tagung-564-file-1082-p-127866.html. Accessed 19 July 2013

4. Fluorspar The mineral fluorspar consists of 51.1% calcium and 48.9% fluorine in its pure form (CaF2). In this case, it is colorless and transparent but different colors can be induced by impurities in the crystal structure. Most fluorspar is extracted either in pure veins or in association with lead, silver, or zinc ores. Commercial fluorspar is graded according to its quality and its specification into acid-grade, metallurgical grade and ceramic grade.1 The largest current producer of fluorspar is China, followed by Mexico.

Figure 1: Distribution of fluorspar production2 and corresponding scores of the producing countries in the Human Development Index (HDI)3, Environmental Performance Index (EPI)4 and World Governance Indicators (WGI)5. Both the EPI and WGI are used to assess supply risks with the EU methodology for determining critical raw materials6. CHN = China; MEX = Mexico. After dropping to a price of 0.101 US$/kg in 2006, the average price of metallurgical grade fluorspar rose to approximately 0.11 US$/kg* in 2009. It is estimated that the price felt back to an amount of 0.101 US$/kg in 2010.7 The price of acid grade fluorspar is approximately double that value.

*

Price: c.i.f. U.S. port

Unit value (1000 USD/t)

0.25

0.20

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0.00 1975

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Year Figure 2: Fluorspar price development during 1975 – 2006. The unit value is defined as the value of 1 t of fluorspar apparent consumption (estimated).8

Uses and Substitutability Hydrofluoric acid Fluorspar is widely used in the manufacturing of hydrofluoric acid or HF (52% of its end use) which serves as feedstock for many different chemical processes. Hydrofluoric acid from fluorite (acid grade) is used in the synthesis of fluorocarbons (CFCs, HCFCs, HFCs) or fluorine-bearing chemicals such as pharmaceuticals, agrochemicals, non-stick coatings as well as in uranium processing. Another application of hydrofluoric acid is as a catalyst for the petroleum industry.9 Fluorosilicic acid from the production of phosphoric acid from apatite and fluorapatite has the potential to serve as a substitute for fluorspar as a source of fluorine in HF production.10 Other possible substitutes are sodium fluoride, and sodium fluorosilicate.1 Nevertheless, these substitutes are just principle alternatives, since none of them are put into practice yet.

Steel The steel sector consumes about 25% of total fluorspar. Metallurgical grade fluorspar is added as flux in the manufacture of steel in open hearth oxygen and electric arc furnaces. Fluorspar lowers the melting point and reduces slag viscosity. It can be substituted with aluminium smelting dross11, borax, calcium chloride, iron oxides, manganese ore, silica sand and titanium oxide.10

Aluminium With a market share of 18%, the aluminum sector is the third largest consumer of fluorspar. The reason for this is that aluminum cannot be produced by an aqueous electrolytic process because hydrogen is electrochemically much nobler than aluminum. Thus, liquid aluminum is produced by the electrolytic

reduction of alumina (Al2O3) dissolved in an electrolyte (bath) containing approximately 65% cryolite (NaF3∙3NaF). Synthetic cryolite is made from fluorspar (CaF2) by treating it with sulfuric acid to produce hydrofluoric acid which is then reacted with sodium oxide (Na2O) and alumina to produce cryolite. Besides serving as a solvent, cryolite lowers the melting point of the aluminium electrolysis bath to below 1000°C.1,9 Recent advances in the aluminium industry have decreased the consumption of fluorspar. In order to minimize emissions of hydrogen fluoride (HF), fume treatment plants are used to capture the HF from the cells and recycle it as aluminium fluoride for use in the smelting process.12 In addition, aluminium fluoride (AlF3), also produced using HF, is used in the production of aluminium. In principle, fluorosilic acid, obtained from phosphate rock, can be used to produce HF (and thus synthetic cryolite and AlF3), but this process has not been implemented on a large scale yet.9 Therefore, fluorspar cannot be substituted in electrolysis-based aluminium production. A corbothermic reduction process, which does not require fluorspar, is currently being developed by Alcoa (pilot stage).†

Others In the residual market share (5%) ceramic grade fluorspar is used in milky or coloured glass or glass fibers, which may contain 10 – 20% fluorite. Further applications are enamels for metallic or ceramic substrates containing between 3 – 10% fluorite. Regarding these applications fluorspar is inserted as opacifier. Finally, the addition of ceramic grade fluorspar to raw materials for cement enhances the clinkering temperature to 50 – 150 ºC.9

†

SINTEF

Summary Fluorspar is used as the main source of fluorine. As such, either the fluorine may be substitutable in a process (e.g. in the steel industry) or alternative sources of fluorine may be used (such as fluorosilicic acid). It is unclear at this time to what extent (by-product) fluorisilicic acid may supplant fluorspar as the principle source of fluorine. In any case, this process would be a slow one.

Figure 3: Distribution of end-uses and corresponding substitutability assessment for fluorspar. The manner and scaling of the assessment is compatible with the work of the Ad-hoc Working Group on Defining Critical Raw Materials (2010).

References 1 2 3

British Geological Survey (2011) Fluorspar Reichl C, Schatz M, Zsak G (2013) World Mining Data: Minerals Production United Nations Development Programme (UNDP) (2013) The 2013 Human Development Report – "The Rise of the South: Human Progress in a Diverse World" 4 Yale Center for Environmental Law and Policy (YCELP) (2013) Downloads | Environmental Performance Index. http://epi.yale.edu/downloads. Accessed 26 July 2013 5 World Bank Group (2013) Worldwide Governance Indicators. http://info.worldbank.org/governance/wgi/sc_country.asp. Accessed 26 July 2013 6 Ad-hoc Working Group on defining critical raw materials (2010) Critical raw materials for the EU: European Commission 7 Miller, M. M. (2011) Fluorspar, in: U.S. Geological Survey (ed.) Mineral Commodity Summaries 2011, pp. 56–57 8 Kelly, T., Miller, M. (2012) Fluorspar: Supply-Demand Statistics, in: U.S. Geological Survey (ed.) Minerals Information 9 Aigueperse, J., Mollard, P., Devillers, D., Chemla, M., Faron, R., Romano, R., Cuer, J. P. (2000) Fluorine Compounds, Inorganic, in: Ullmann's Encyclopedia of Industrial Chemistry, pp. 397–441. Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA 10 Miller, M. M. (2013) Fluorspar, in: U.S. Geological Survey (ed.) Mineral commodity summaries 2013, pp. 56–57 11 SP Sveriges Tekniska Forskningsinstitut AB (2013) Fluorspar Substitutability. personal notification 12 Alstom (2013) Air quality control solutions for the aluminium industry. http://www.alstom.com/Global/Power/Resources/Documents/Brochures/air-quality-control-for-thealuminium-industry-general-brochure.pdf

5. Gallium Like aluminium, gallium is a soft, silvery metal.1 A particular concern for gallium criticality is its main use in growing and emerging markets. Gallium is almost exclusively used as III-V semiconductor material in electronics applications2 that grew fast in recent years and are forecast to continue growing rapidly in the coming decades3,4. Traces of gallium can be found in the minerals diaspore, sphalerite, germanite, bauxite and coal.1 As it is primarily obtained from the circulation liquor in the Bayer process for aluminium oxide manufacture, gallium is a by-product of aluminium production and is not extracted in its own right.5 After a period in which the price of gallium increased up to a peak of 688 US$/kg*† in 2011, the price has declined. In 2013 the price of gallium decreased continuously. Metal Bulletin #937} The leading producer is China, which has increased its production capacity by a factor of five6. Its competitors are Kazakhstan and Ukraine.

Figure 1: Distribution of gallium production7 and corresponding scores of the producing countries in the Human Development Index (HDI),8 Environmental Performance Index (EPI)9 and World Governance Indicators (WGI).10 Both the EPI and WGI are used to assess supply risks with the EU methodology for determining critical raw materials.11 CHN = China; KAZ = Kazakhstan; URK = Ukraine.

* †

Price, yearend, dollars per kilogram: Estimated based on the average values of U.S. imports for 99.9999% -and 99.99999% -pure gallium

800

Unit value (1000 USD/t)

700 600

500 400 300 200 100 0 1980

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Year Figure 2: Gallium price development during 1980 – 2011. The unit value is defined as the value of 1 ton (t) of gallium apparent consumption (estimated).12

Uses and substitutability Gallium is almost exclusively used in III-V semiconductor compounds, in particular GaAs and GaN, for two main applications fields:  

Integrated circuits Optoelectronic devices (LEDs, laser diodes and photo detectors, solar cells)

Integrated circuits Semiconductor compounds used in integrated circuits (ICs) are currently the major application of gallium constituting about 70% of overall gallium use.2 Integrated circuits with gallium compound semiconductors specifically GaAs and GaN, are used in high-power and high-frequency electronics, due to higher electron mobility, breakdown voltages and saturation velocity than silicon-based ICs. This faster and cleaner electron transfer enables stable high power (wireless) communication devices, such as smart phones, amplifiers, digital switches and microwave applications.4,13 These applications are all rapidly growing.3 Due to their high radiation and temperature resistance the gallium-based ICs are ideal for space applications, such as satellite dishes, and military use. The Ga compounds are either melt-grown wafers or thin films prepared by metal organic chemical vapour deposition (MOCVD) from trimethyl gallium precursors. Options for substitution of gallium in integrated systems are limited because, as a minor and relative costly metal, Ga-based IC were specially develop for applications where established Si-based semiconductor and integrated circuit technology do not fulfil the applications’ requirements. SiGe is a commercially available alternative to GaAs exhibiting similar properties required for high-power and high-frequency electronics.14 SiGe is able to replace GaAs wafers in some integrated circuits (high performance radio frequency applications), but it uses another critical raw material, germanium. Note that SiGe was developed as costeffective alternative to GaAs and not because of the gallium criticality as such. Integrated circuits are core

components applied in a broad range of electronic product making component substitution instead of material substitution also not possible without function or performance loss. In conclusion, currently substitution of gallium in integrated circuits is possible for a limited number of applications but only by materials containing another critical raw material.

Optoelectronic devices Optoelectronics devices, such as laser diodes, photodiodes, LEDs and solar cells, constitute the other main use of gallium. LEDs are used in lighting and displays and the demand for LEDs in solid state lighting applications is growing fast due to governmental bans on the use of incandescent light bulbs. Photodiodes are used in e.g. remote controls and laser diodes are used in telecommunication optical media (CD, DVD) players. Gallium-based solar cells are exclusively used for space and military applications and concentrated solar power. Thin film copper-indium-gallium-selenide (CIGS) solar cells are an emerging technology for low-cost and high efficiency solar power generation. As for the integrated circuits, gallium is combined with arsenic (GaAs), sulphur (GaN) or phosphor (GaP), often including indium (InGaAs) or aluminium (AlGaAs), to produce III-V semiconductor compounds. Due to their high electron velocity, compared to silicon, and their direct bandgap, Ga based semiconductors are well suited to either convert electricity to light (LEDs, laser diodes) or vice versa (solar cells, photodiodes). In multilayer stacks of these compounds a diode, created by a so-called p-n junction, functions as the active component in the optoelectronic devices. The gallium compounds are typically prepared as thin films by metal organic chemical vapour deposition (MOCVD). Hence, gallium enters the device market in the form of trimethyl gallium MOCVD precursors. Zinc oxide (ZnO), an II-VI compound semiconductor, is being investigated as an alternative to GaN in LEDs and laser diodes. To obtain the p-n junction for the optoelectronically active diode both n-type and p-type doped ZnO is needed. However, p-type ZnO has limited stability and thus it is not (yet) a feasible substitute. Similar difficulties obtaining stable p-type compounds restrict the use of other II-VI compounds such as MgSe and ZnSe. From a component point of view, incandescent light bulbs and fluorescent light are obvious substitutes for gallium-containing solid state lighting. However, incandescent light bulbs are being phased out in the EU and other countries, because of their low energy efficiency. Fluorescent lighting relies on phosphors containing rare earth elements, which are also critical raw materials. Organic LEDs (OLEDs) are an emerging alternative technology to solid state lighting. OLED displays and light concepts have been introduced on the market by the major electronics companies. However, for now there are only a limited number of applications, because current OLEDs are not competitive with solid state LEDs on price and long-term durability. It is expected that for at least the coming 5-10 years OLEDs will remain a relative niche compared to solid state lighting. Stacks of GaAs, (Al)InGaP/As films make so-called multijunction solar cells, which are the only solar cell types with conversion efficiency of more than 30%. Combined with a high temperature and radiation resistance they are very high performance solar cells. However gallium-based solar cells are considerably more expensive than other solar cell types, restricting their use to special applications, such as satellites and concentrated solar power.15 As a consequence the possibilities for substitution by other solar cell types, such as established silicon based solar cells, are limited without a significant loss in performance. Of the emerging second and third generation solar cell technologies copper-indium-gallium-diselenide (CIGS) thin film solar cells are potential substitutes, because of their radiation resistance and tolerance toward defects. However, the conversion efficiency is lower and they also contain critical metals gallium and indium.

Material substitution by other III-V or II-VI semiconductor compounds suffers from the same limitations as described for LEDs. CIGS thin film solar cells are a growing application that is forecasted to attain a significant share (20%) of the fast growing photovoltaic market in the coming decades. As a thin film solar technology it holds the potential of lower manufacturing costs and better product integration compared to the state-of-the-art silicon wafer based solar modules. CIGS solar modules are manufactured on an industrial scale by around five companies world-wide. The industrial and academic CIGS community is aware of the criticality of gallium, but opinions on the need for substitution vary. A one-to-one material substitution by copper-zinc-tinselenide/sulphide (CZTS) has become a significant R&D theme in the recent years. 16 However, with record conversion efficiency (2013 figures) of only 11.1% compared to 20.4% for CIGS solar cells, commercial production of CZTS modules is not likely within the coming 10 years. Also due to the strong cost reduction in the last 3 years established silicon based solar technology is an obvious substitute for CIGS. In conclusion currently substitution of gallium in optoelectronic devices (LEDs, laser diodes, photodetectors and solar cells) is limitedly possible and only at a loss of performance.

Summary Prime examples for the utility of gallium are the use of gallium arsenide (GaAs) integrated circuits for wireless communication (e.g. smart phones) and of gallium nitride (GaN) in solid state lighting (LED). Substitution of gallium is limited because, as a minor and relative costly material, gallium is primarily used in applications where there are no comparable alternatives.

Figure 3: Distribution of end-uses and corresponding substitutability assessment for gallium. The manner and scaling of the assessment is compatible with the work of the Ad-hoc Working Group on Defining Critical Raw Materials (2010).

References 1 2 3 4 5 6

7 8 9 10 11 12 13 14 15 16

Royal Society of Chemistry (2013) Gallium - Element information, properties and uses. http://www.rsc.org/periodic-table/element/31/gallium. Accessed 7 August 2013 Jaskula, B. (2013) Gallium, in: U.S. Geological Survey (ed.) Mineral commodity summaries 2013, pp. 58–59 Mikolajczak C, Murphy MD (2011) Sustainability of Indium and Gallium In the Face of Emerging Markets Phipps, G., Mikolajczak, C., Guckes, T. (2008) Indium and Gallium: long-term supply. Renewable energy focus 9(4), 58–59 Greber, J. F. (2000) Gallium and Gallium Compounds, in: Ullmann's Encyclopedia of Industrial Chemistry, pp. 335–340. Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA Strategic Metal Investments Ltd. (2013) By-Product Metals: The Aluminum-Gallium Relationship Pt. II Strategic Metal Report. http://strategic-metal.typepad.com/strategic-metal-report/2013/01/by-productmetals-the-aluminum-gallium-relationship-pt-ii.html. Accessed 7 August 2013 Reichl C, Schatz M, Zsak G (2013) World Mining Data: Production of Mineral Raw Materials of individual Countries, by Minerals. in 2011 in metric tonnes United Nations Development Programme (UNDP) (2013) The 2013 Human Development Report – "The Rise of the South: Human Progress in a Diverse World" Yale Center for Environmental Law and Policy (YCELP) (2013) Downloads | Environmental Performance Index. http://epi.yale.edu/downloads. Accessed 26 July 2013 World Bank Group (2013) Worldwide Governance Indicators. http://info.worldbank.org/governance/wgi/sc_country.asp. Accessed 26 July 2013 Ad-hoc Working Group on defining critical raw materials (2010) Critical raw materials for the EU: European Commission DiFrancesco, C., Kramer, D., Jaskula, B. (2012) Gallium: Supply-Demand Statistics, in: U.S. Geological Survey Minerals Information Gold Canyon Resources Inc. Cordero Gallium project. http://www.goldcanyon.ca/s/Cordero_Gallium.asp?ReportID=363062. Accessed 7 August 2013 Gielen, A. J. Green Sustainability and Recycling: ISA world, strategic research agenda, Bleiwas, D. (2010) Byproduct mineral commodities used for the production of photovoltaic cells. U.S. Geological Survey Circular 1365 Delbos, S. (2012) Kesterite thin films for photovoltaics: a review. EPJ Photovoltaics 3. 10.1051/epjpv/2012008

6. Germanium Germanium is a hard and brittle semi-conducting metal discovered in 1886. Its position (IV A) in the periodic table (C-Si-Ge-Sn-Pb) indicates that it has properties similar to silicon. Germanium was initially used industrially in transistors due to its semi-conductor properties. It was later on replaced by silicon, which has better behaviour with respect to temperature. Its semi-conductor properties, however, remain of strong interest in some high-performance applications such as photovoltaics. It is now mostly used in fibre optics to increase their refractive index (reduce transmission losses) and in infrared detection/vision due to its transparency to infrared radiation. Furthermore it is used as a catalyst in organic chemistry.1 Recycled germanium is estimated by USGS to represent about 30% of the worldwide consumption. This consists of a notable (60%) fraction of germanium being discarded as scrap during the processing of most optical devices, which can then be recycled.2 Recycling rates for fibre optic scrap are reported as high as 80%.3 As a consequence, about 50% of the germanium metal used for electronic and optic are recycled in short cycle. Germanium is not mined as a principal metal but is obtained as a by-product of zinc refining and from flyash of coal-fired power plants.4 Currently, the production of germanium is dominated by China, followed by the Ukraine and Russia (see Figure 1). The price of germanium reached a very high level in 2011 (1450 US$/kg in 2011; zone refined germanium producer yearend price; see also Figure 2).2. After decreasing until the middle of 2012, the price of germanium rose back to an even higher level than before recently within one year (2013).5

Figure 1: Distribution of germanium production6 and corresponding scores of the producing countries in the Human Development Index (HDI),7 Environmental Performance Index (EPI),8 and World Governance Indicators (WGI).9 Both the EPI and WGI are used to assess supply risks with the EU methodology for determining critical raw materials.10 CHN = China; UKR = Ukraine; RUS = Russia.

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Year Figure 2: Germanium price development during 1980 – 2011. The unit value is the value of 1 metric ton (t) of germanium metal apparent consumption (estimated).11

Uses and substitutability Germanium is used mainly in three forms12: 

Germanium metal: in the area of infrared optics, photovoltaics and other electronic applications (totalling about 45% of world demand);



Germanium oxides (GeO2): as catalyst for PET production (particularly in Japan), which accounts for 25% of world use;



Germanium chlorite (GeCl4): for fibre optic production (particularly in the USA), accounting for about 30% of global use.

Fibre Optics This is considered the major use of germanium worldwide, accounting for 30-50% of use12. Germanium is used as a doping element in optical fibres, which contain approximately 4% germanium, the rest being silicon oxide. The function of germanium in optical fibre is to increase its refractive index, helping to contain the light within the fibre and enabling the transmission of the digital signal. This technology is a strong enabler of today’s connectivity, forming the backbone of telecommunications and internet systems. Uptake will continue to increase in line with the current trend to digitally connect final consumers through fibre optics (Fibre to the Home – FTTH ; Fibre to the Building – FTTB). As may be expected for such an important application, there is existing research to develop and improve fibre optic-based data transport which has spawned new fibre technologies: photonic hollow fibre (from Corning, the main fibre optics producer), fibres with tellurium layers, “OM2” fibres and erbium-doped fibres that enable optical signal amplification12, some of which (e.g. hollow-fibre) are based on germanium-free technology.13 Although germanium has been preferred for fibre optic doping, phosphorous-based doping

(P2O5) can also be used to raise the refractive index of silica, and other doping elements can be used to decrease this refractive index.14,15

Polymerization catalyst Germanium dioxide (GeO2) is a catalyst for the polymerisation of polyesters. Production of polyethylene terephthalate (PET), used for example in plastic bottles, is a major use.2 Polymerization of resins to produce PET can also be achieved using alternative catalysts. Sb2O3 is a possible alternative and has been historically used for PET production, in particular in the US. Its potential health effects (“limited evidence of carcinogenic effects”) is, however, a cause of concern although different organisations have reported that its use for PET production is safe under normal circumstances. 16 Further potential substitutes are antimony triacetate, an aluminium-based catalyst (identified by Toyobo) and a titanium-based catalyst (but which has the disadvantage of giving a yellowish colour to PET).1,12

Infrared optics Germanium, being transparent to infrared radiation, is used to make lenses and window panes for infrared detectors and cameras, both in the military and the civilian sector. Both the lens and the detection sensor in which the infrared radiation is converted to electricity typically use germanium. It is thus used in numerous applications such as surveillance, night vision and satellite systems.1 Zinc selenide can substitute for germanium metal in selected infrared applications, but with lower performance.2 Tellurium-based glass has also been announced as a potential substitute for infrared-based applications.

Parts for electrical and solar equipement In the domain of photovoltaics (PV), germanium is used mostly in high-performance multi-junction cells (typically III-V cells). Due to high costs, these cells have been historically used in premium applications where high performance per surface and weight ratio was important, namely the PV panels used in satellite systems. With the development of Concentrated Solar PV (CPV) on-ground systems, it becomes possible to use less PV cells by concentrating the solar rays on a smaller surface through and optical device (e.g. Fresnel lens), which reduces the pressure on cost. Multi-junction cells used in conjunction with on-ground CPV systems thus have a potential for future development. Germanium is typically used in the bottom-cell part of triplejunction PV, for the substrate, base and emitter layers, thanks to its lattice constant, robustness, low cost, abundance and ease of production. Germanium is very useful in capturing longer wavelengths. Current triple-junction cells having now reached efficiency levels close to their theoretical maximum (>43%). Research has developed towards even higher performance through the study of quadruple-layer multijunction cells. In terms of substitution, it can be noted that triple-junction and quadruple-junction cells can also be based on non-germanium materials (e.g. containing InGaP, AlGaInP, InGaAsP, InGaAs materials).17 This technology is, however, still at the research level. On the electronic side, the specific SiGe transistors benefit from the low-cost of silicon processing and of the high-speed switching characteristics of germanium. Reduced energy consumption of SiGe transistors with respect to silicon-based transistor creates a strong potential for the third generation of mobile phones with high-speed wireless applications.12 Germanium is also used in high-brightness LEDs.

Silicon can be a less-expensive substitute to germanium in some electronic applications.2 The fact that such substitution is not yet in place relates to the higher performance achieved when using germanium. Some metallic compounds can be used for high-frequency electronics and some light-emitting diode applications.

Others Other diverse uses of germanium exist, for example: use as an alloying element (0.35%) for tin, or Al-Mg alloys, to increase their hardness; soldering material (12% Ge / 88% Au) for gold-based dental prosthesis; luminescent material (red-coloured); photographic and wide-angle lenses; ceramics, with (Na2O/TiO2 or K2O/Ta2O5; gamma-ray detector Bi2(GeO3)3; bismuth germanate oxide crystals (BGO – Bi4Ge3O12) for various detection technology (scintillation, tomography, gamma spectroscopy); fluorescent paint (MgGeO3); superconductors (Nb3Ge); thermocouple and thermoelectricity; medication (diverse uses currently under investigation); germanium-containing products are sold in the US as antioxidants.

Summary Germanium material has demonstrated to be well suited for several major applications with comparable importance (~25-30% of Ge usage): fiber optics, infrared optics and polymer catalysts. Due to a history of using a germanium-free catalyst for PET production in the USA, the substitution by Sb2O3 is judged reasonable but suffers from persisting concerns about possible health effects. Both for fiber-optics and infrared optics, no evidence has been identified of cheap and off-the-shelf substitution solutions for the breadth of these applications. Possibilities exist, but are overall either characterized by a likely loss of performance, a lack of industrial maturity (e.g. still at the research level), or an uncertainties about their ability to fulfil all the requirements of the product/solution or industrialization capabilities. In the case of fiber-optics, which has nowadays almost a status of a commodity-product, the production volume puts a specific pressure on the substitution potential. For infrared-optics, although the use is less wide-spread, the market has been evolving towards wider use (e.g. security, maybe tomorrow consumer equipment). For solar applications (photovoltaic, e.g. satellite PV panels) and high-profile electronic applications, it is judged that the level of requirements justifies the consideration as “premium” applications, where performance largely dominates cost issues.

Figure 3: Distribution of end-uses10 and corresponding substitutability assessment for germanium. The manner and scaling of the assessment is compatible with the work of the Ad-hoc Working Group on Defining Critical Raw Materials (2010).

References 1 2 3

4 5 6 7 8 9 10 11 12

13 14 15 16

17

Butterman W.C., Jorgenson JD (2005) Germanium. Open-File Report 2004-1218 Guberman, D. E. (2013) Germanium, in: U.S. Geological Survey (ed.) Mineral commodity summaries 2013 Bell Labs - Lucent Technology Bell Labs Innovative Germanium-Recovery Process is Economically, Environmentally Friendly. Science Daily. http://www.sciencedaily.com/releases/1997/10/971023172421.htm. Accessed 23 August 2013 Willis P, Chapman A, Fryer A (2012) Study on by-products of copper, lead, zinc and nickel Metal Bulletin Germanium Metal Rotterdam $/kg: Latest Metal Prices Tracking and Comparison Tool. http://www.metalbulletin.com/My-price-book.html?price=42087. Accessed 3 September 2013 Reichl C, Schatz M, Zsak G (2013) World Mining Data: Production of Mineral Raw Materials of individual Countries, by Minerals. in 2011 in metric tonnes United Nations Development Programme (UNDP) (2013) The 2013 Human Development Report – "The Rise of the South: Human Progress in a Diverse World" Yale Center for Environmental Law and Policy (YCELP) (2013) Downloads | Environmental Performance Index. http://epi.yale.edu/downloads. Accessed 26 July 2013 World Bank Group (2013) Worldwide Governance Indicators. http://info.worldbank.org/governance/wgi/sc_country.asp. Accessed 26 July 2013 Ad-hoc Working Group on defining critical raw materials (2010) Critical raw materials for the EU: European Commission Kelly, T., George, M., Jasinski, S., Gabby, P., Guberman, D. (2012) Germanium: Supply-Demand Statistics, in: U.S. Geological Survey Minerals Information Christmann P, Angel JBL, Barthelemy F, Benhamou G, Billa M, Gentilhomme P, Hocquard C, Maldan F, Martel-Jantin B, Monthel J (2011) Panorama du marche 2011 de germanium Rapport Final. BRGM/RP-60584-FR Amezcua Correa R (2009) Development of hollow-core photonic bandgap fibre free of surface modes. Ph.D. thesis. Southampton Brown, T. G. (1995) Optical Fibers and Fiber-Optic Communications, in: Bass M (ed.) Handbook of optics, 2nd edn., pp. 10.1-10.50. New York: McGraw-Hill CEA internal. Personal communications International Antimony Association (2012) Antimony trioxide. http://www.antimony.com/files/cms1/publications/i2a-factsheet-trioxyde-v3.pdf. Accessed 30 August 2013 Luque A, Hegedus S (2011) Handbook of photovoltaic science and engineering, 2nd edn. Chichester: Wiley

7. Natural graphite Natural graphite is a form of carbon where atoms are arranged in layers that have weak bonds between each other. The particular layered structure of graphite makes it one of the most stable and unreactive materials. Graphite also retains its strength and physical properties at temperatures in excess of 2200 ºC. The weak bond between layers causes graphite to be soft and slippery, resulting in a high natural lubricity. This layered structure can be modified by techniques such as intercalation where atoms of another element are incorporated between the layers to achieve certain properties such as superconductivity, or impregnation, where graphite is infused with other materials to achieve similar results as intercalation. 1 Natural graphite is mined in three qualities: vein, flake and microcrystalline (often referred to as amorphous graphite), with different uses.2 Mines can be either open pit or underground.3 Current supply of natural graphite is dominated by Chinese producers. Synthetic graphite is concentrated in countries/regions such as USA, Europe and Japan. Because of higher production cost and process knowledge, the graphite market is still dominated by natural graphite.

Figure 1: Distribution of natural graphite production4 and corresponding scores of the producing countries in the Human Development Index (HDI)5, Environmental Performance Index (EPI)6, and World Governance Indicators (WGI)7. Both the EPI and WGI are used to assess supply risks with the EU methodology for determining critical raw materials.8 CHN = China; IND = India; BRA = Brazil. After a short decreasing period down to a price of natural graphite of 0.69 US$/kg in 2009, the price of natural graphite increased up to a value of 1.18 US$/kg in 2011.9 These prices do represent the monetary values of the quality flake. Amorphous was five times cheaper (on average) than flake natural graphite during 2008 to 2011.

Unit value (1000 USD/t)

1.20 1.00 0.80 0.60 0.40

0.20 0.00 1980

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Year Figure 2: Natural graphite price development during 1980 – 2011. The unit value is defined as the value of 1 ton (t) of natural graphite in current dollars (estimated).10

Uses and Substitutability Steel Industry The steel industry represents a 24% share of natural graphite consumption. In this industry, graphite (both natural and synthetic) is used for its high temperature stability, thermal shock resistance, chemical inertness and ability to withstand corrosion. Natural graphite is used as a refractory liner for furnaces, ladles and crucibles in the continuous casting of steel and as an agent to increase the carbon content of steel.11 Natural graphite can be substituted in the steel industry (increasing the carbon content of steel) by use of manufactured graphite powder, scrap from discarded machine shapes, and calcined petroleum coke.3,9.

Foundries Foundries (factories that produce metal castings) account for a further 24% of the share of natural graphite use. Graphite is used in blocks that form the lining of the blast furnace due to its high temperature stability (refractory). Graphite is ideal because it is highly unreactive and resistant to acids, alkalis and other chemical substances.11 In principle, natural graphite can be substituted for manufactured graphite powder and calcined petroleum coke.3,9

Crucible production Graphite is the main component in the manufacture of crucibles, and 15% of natural graphite is consumed in this industry alone. Natural graphite is the preferred material due to its corrosion resistance, thermal shock resistance and oxidation resistance capacity. Graphite can be substituted by silicon carbide1, however, it does have better properties than alternatives.

Electrical applications A share of 12% of the consumption of natural graphite is attributed to electrical applications. Most important are the manufacture of carbon brushes in electric motors, where graphite is preferred due to its high stability.1 In many cases natural graphite can be substituted by synthetic graphite.3

Refractories The refractory industry consumes 8% of natural graphite. Due to graphite’s high temperature stability, thermal shock resistance and chemical inertness, graphite is ideal for use as a component in bricks that line furnaces such as oxygen furnace, electric arc furnace and blast furnaces.1 Silicon carbide can be used as a substitute for graphite in refractory applications. 12 Moreover, zirconia and SiAlON are potential alternatives. Synthetic graphite does not compete with natural graphite in refractories.13

Lubricants Graphite possesses exceptional lubricating properties, which make it highly suitable for use in lubricants. This application accounts for 5% of total natural graphite use, in the form of graphite powder. Its applications include the use in heavy machinery to reduce friction between parts where high temperatures prevail, such as in sliding bearings, piston rings, guide bearings and steam joint rings, sliding and sealing rings for mechanical seals, vacuum pumps, compressor and pumps.1. Natural graphite can be substituted by synthetic graphite or by molybdenum disulfide (but the latter is prone to oxidation).3,12

Pencils Pencils, although traditionally known as “lead” pencils, contain nontoxic microcrystalline (“amorphous”) natural graphite mixed with clay. Graphite is suitable for this application because the weakly held layers of carbon atoms slide easily over each other and allow for a black streak to be left on paper.14 Substitutes for pencils include the use of pens and ink as well as coloured pigments or charcoal.

Batteries Batteries account for 4% of natural graphite consumption. Here graphite (both natural and synthetic) is used for anodes due to its electrical conductivity.1,3 An alternative to graphite anodes for lithium-ion batteries has been developed (with improved properties); the production technology is currently at the pilot stage.15

Summary In principle, it is possible to substitute natural graphite by either its synthetic alternative (e.g. in batteries or for increasing the carbon content of steel), by replacing the product as in the case of pencils, by other compounds as in high temperature applications (e.g. refractories). In the latter case, it is difficult to fully substitute graphite while retaining the same level of performance.

Figure 3: Distribution of end-uses and corresponding substitutability assessment for graphite. The manner and scaling of the assessment is compatible with the work of the Ad-hoc Working Group on Defining Critical Raw Materials (2010).

References 1 2 3

4 5 6 7 8 9 10 11 12 13

14

15

Graphite Stocks (2013) How Graphite is Used. http://www.graphitestocks.com/how-graphite-isused.php/. Accessed 26 June 2013 Frohs, W., Sturm, F. von, Wege, E., Nutsch, G., Handl, W. (2010) Carbon, 3. Graphite, in: Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA Jäger, H., Frohs, W., Banek, M., Christ, M., Daimer, J., Fendt, F., Friedrich, C., Gojny, F., Hiltmann, F., Meyer zu Reckendorf, R., Montminy, J., Ostermann, H., Müller, N., Wimmer, K., Sturm, F. von, Wege, E., Roussel, K., Handl, W. (2010) Carbon, 4. Industrial Carbons, in: Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA Reichl C, Schatz M, Zsak G (2013) World Mining Data: Production of Mineral Raw Materials of individual Countries, by Minerals. in 2011 in metric tonnes United Nations Development Programme (UNDP) (2013) The 2013 Human Development Report – "The Rise of the South: Human Progress in a Diverse World" Yale Center for Environmental Law and Policy (YCELP) (2013) Downloads | Environmental Performance Index. http://epi.yale.edu/downloads. Accessed 26 July 2013 World Bank Group (2013) Worldwide Governance Indicators. http://info.worldbank.org/governance/wgi/sc_country.asp. Accessed 26 July 2013 Ad-hoc Working Group on defining critical raw materials (2010) Critical raw materials for the EU: European Commission Olson, D. W. (2013) Graphite, in: U.S. Geological Survey (ed.) Mineral Commodity Summaries 2013, pp. 68–69 Sznopek, J., Olson, D. (2012) Graphite: Supply-Demand Statistics, in: U.S. Geological Survey Minerals Information The A to Z of Materials (2013) Graphite (C) – Classifications, Properties and Applications of Graphite. http://www.azom.com/article.aspx?ArticleID=1630. Accessed 26 June 2013 Kogel J, Trivedi N, Barker J (2006) Industrial Minerals and Rocks: Commodities, Markets, and Users. Diniz V (2013) What is Synthetic Graphite? Asbury Carbon's Stephen Riddle Explains. http://resourceinvestingnews.com/50143-what-is-synthetic-graphite-asbury-carbons-stephen-riddleexplains.html. Accessed 31 August 2013 Preserve Articles (2013) What are the Essentials properties and uses of Graphite? http://www.preservearticles.com/201012291918/properties-and-uses-of-graphite.html. Accessed 26 June 2013 Nexeon (2013) Unique silicon anode technology for the next generation of lithium-ion batteries. http://www.nexeon.co.uk/. Accessed 31 August 2013

8. Indium Indium is a silvery-white metal that is chemically and physically similar to gallium and thallium (all in Group III of the periodic table). With a melting point of 157 °C, indium belongs to a group of low melting point posttransition metals that are very soft and malleable. A particular concern for indium criticality is its main use in growing and emerging markets. Indium is exclusively used in electronics applications that have grown and are forecasted to continue to grow at high rates of 5 – 30% per year1–3. A prime example is the use of indium doped tin oxide (ITO) in flat panel displays (LCD, plasma screens, e-paper), which constitute the major use (75%) of indium4. The demand for flat panel displays quickly accelerated due to increasing use of flat screen televisions, PC monitors, notebooks and tablets and mobile phones. At the same time organic electronics, such as active-matrix organic light-emitting diode (AMOLED) displays, organic light-emitting diode (OLED) lighting and photovoltaics, also using ITO, and thin film CuInGaSe2 (CIGS) photovoltaics are emerging technologies forecasted to also grow quickly in the coming decade1,3,5. However, there is a significant awareness of the indium criticality in the electronics industry and considerable academic and industrial effort is put into the development of substitutes for indium 6. The price of indium represents this fact in one dimension as well, since the price was already high and even increased to an annual average value of 720 US$/kg in 2011*.4 The price decreased in the year 2011 and then was stable above 500US$ per kg in 2012. In 2013 the price started to increase again.7

Figure 1: Distribution of indium production8 and corresponding scores of the producing countries in the Human Development Index (HDI)9, Environmental Performance Index (EPI)10, and World Governance Indicators (WGI)11. Both the EPI and WGI are used to assess supply risks with the EU methodology for determining critical raw materials12. CHN = China; CAN = Canada; KOR = South Korea; JPN = Japan. Indium is mainly obtained as a by-product from zinc concentrates. While China is the largest producer worldwide, there is also significant production in Canada, Korea and Japan. Since 2012, primary production has increased both in China and in the rest of the world, including Europe. This has enabled the Western *

New York dealer: Price is based on 99.99%-minimum-purity indium at warehouse (Rotterdam); cost, insurance, and freight (in minimum lots of 50 kilograms).

world to supply an increasing share of its demand, while China’s exports have decreased and they have been stockpiling some of their output (without a noticeable price effect). Forecasts of growth for future indium applications have also been considerably reduced as the CIG (copper-indium-gallium) technology has failed to become a competitive alternative for PV applications.13 1000

Unit value (1000 USD/t)

900 800 700 600 500 400 300 200 100 0 1980

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Year Figure 2: Indium price development during 1980 – 2011. The unit value is the value, in current dollars, of 1 metric ton (t) of indium apparent consumption (estimated).14

Uses and substitutability The uses of indium can be grouped into three types of indium compounds15: 





Indium-tin-oxide (ITO) thin films for o Flat panel displays o Optoelectronic windows (architectural glass / windscreens) Indium compounds (III-V semiconductors) for o LEDs o Integrated circuits o Thin film CuInGaSe2 (CIGS) solar cells Alloys for o Low-melting point solders o Dental alloys o Surface coatings o Minor alloys

Flat panel displays The major use of indium is found in thin film indium-tin-oxide (ITO) windows for flat panel displays2,4. Television screens, PC monitors, notebook screens and touchscreens on mobile phones and tablets all require a window that is electrical conducting and optically transparent16. The electrical conductivity facilitates the voltage-triggered switching of the pixels in a display. ITO is a transparent conductive oxide (TCO) that combines a good conductivity with a high optical transparency. In addition ITO has a high

atmospheric stability, i.e. durability, and allows accurate etching of the electrode arrays used to address individual pixels. ITO consists of 90% In2O3 and 10% SnO2 corresponding to a 75 wt% indium content. It is supplied to the flat panel display manufacturing industry as ITO targets for sputter tools. In manufacturing the in-line sputter tools deposit thin (100 nm) ITO films at high rates on large area display glass panels. The flat panel display industry is aware of the criticality and the associated price fluctuations of indium. Considerable R&D effort has been and continues to be focused on finding alternatives for ITO6. Other TCOs, in particular aluminium doped zinc oxide (AZO) and fluorine doped tin oxide (FTO) are possible substitutes for ITO. Both are produced on an industrial scale and at lower cost than ITO. However, in performance both AZO and FTO lags behind ITO. The specific conductivity is respectively a factor of 2 and 4 lower requiring thicker films for a similar electrical performance, which reduces the transparency of the screen. Also AZO and FTO cannot be etched as accurately as ITO, preventing their use in high resolution displays, like the latest generation of mobile phone touchscreens. Finally, AZO is sensitive to degradation by moisture. Emerging amorphous TCOs, like gallium-indium-zinc-oxide (IGZO / IZGO), indium-zinc-oxide (IZO) and zinc-tin-oxide promise properties equal or better than ITO, but are estimated to take at least 5 years to commercialisation. Moreover, although the concentration is lower IGZO and IZO still contain indium. Next to the TCOs there is a range of transparent conductive film technologies under development with an estimated time-to-market of 5 – 10 years, in particular:     

Ultrathin metal films and zinc oxide-metal-zinc oxide multilayers Carbon nanotubes and metal nanowire films Graphene films Organic transparent conductors (PEDOT:PSS) Printed metal grids

All these alternatives under perform on at least one of the properties required for flat panel display application. Apart from the multilayers and the metal grids that outperform ITO, these alternatives do not (yet) exhibit the same good electrical conductivity at a high optical transparency as ITO. The ability to etch the films and the durability of the films needs to be established. The viability of manufacturing on industrial scale at competitive costs still has to be proven for all these technologies. Research and development into display technologies that do not require ITO started form the emerging field of flexible electronics, like organic LED (OLED) displays on foil. Here the low mechanical stability of ITO, which restricts display flexibility, presents an additional driver for finding alternatives to ITO. An organic transparent conductive PEDOT:PSS with a printed silver grid is able to substitute ITO in prototype flexible OLED displays. However, their limited durability has prevented commercialization of ITO-free flexible displays up to now. Active-matrix OLED displays on glass have been introduced in the mobile phones market recently, but these rigid displays use ITO. The only alternative ITO-free display technology available today is LED displays, as used in LED television screens, signage and billboards. LED displays do not need transparent electrodes because individual LED pixels are addressed form the display backsside. However, indium-gallium-nitride-based diodes are the main active components in LED displays. In conclusion, substitution of flat panel displays containing ITO, either by an ITO alternative or a different display technology, is currently not possible without a loss of performance or the use of another indium containing component.

Optoelectronic windows In addition to flat panel displays, another range of applications uses ITO on glass to obtain specific optoelectronic functionalities. The combination of electrical conductivity with a high optical transparency of ITO is used to add an electrical function to glass with a minimum loss in transparency. Also in optoelectronic applications indium is procured as ITO targets for thin film ITO film sputtering. The main optoelectronic window application is architectural glass16. Low-emissivity coatings containing ITO reduce heat losses through windows. In these coatings ITO is part of a multilayer stack including transparent silver films and various atmospheric barriers and adhesion layers. An emerging application in architecture is smart windows that allow light balancing, temperature regulation by IR reflection and integration of transparent sensors. Light balancing is, for example, achieved by controlling the light transmission through an electrochromic film containing ITO. Similar ITO coated smart windows are gradually entering the automotive market. Currently, some cars are equipped with defogging windscreens and defrosting headlights through heating of a resistive ITO coating. Fluorine-doped tin oxide (FTO) is a substitute for ITO in architectural glass. FTO is applied in-line immediately after glass production in float glass lines. The lower specific conductivity of FTO compared to ITO is not an issue because a low conductivity is required for low-emissivity coatings16. Also FTO has a similar high resistance to atmospheric degradation as ITO. In well-packaged low-emissivity multilayers, such as inside double glazing, zinc oxide and aluminium-doped zinc oxide (AZO) are also a feasible substitutes for ITO. The packaging protects the zinc oxide against degradation by moisture from the atmosphere. Heated windscreens and headlights require higher conductivities making FTO and AZO less suitable substitutes. Additionally, the sensitivity of AZO to atmospheric degradation excludes its use in these applications. Emerging amorphous TCOs, like gallium-indium-zinc-oxide (GIZO / IZGO), indium-zincoxide (IZO) and zinc-tin-oxide promise properties equal or better than ITO, but are estimated to take at least 5 years to commercialisation. Moreover, GIZO and IZO still contain indium, although the concentration is lower. A growing application of optoelectronic windows is thin film solar cells. Highly conductive and transparent windows are needed to let sunlight enter the solar cells and transport the generated current away. ITO has been used a window layer in the so-called second generation solar cells, based on thin film cadmium telluride (CdTe), amorphous silicon (aSi) and copper-indium-gallium-diselenide (CIGS). However, FTO or AZO are now state-of-the-art in industrial manufacturing of these thin film solar cells. For the third generation solar cells, organic solar cells (OPV) and dye-sensitized solar cells (DSSC) that are forecasted to be commercialized in 5 to 10 years, ITO is the preferred window material. The chemical aggressiveness of the electrolyte used in DSSC makes replacement of ITO impossible for now. Just as for the flat panel OLED displays, organic transparent conductive PEDOT:PSS with a printed silver grid are able to substitute ITO in OPV, in particular for flexible modules. In conclusion, substitution of ITO in optoelectronic windows is currently possible for architectural windows, but this is not possible without a loss of performance for heated windscreens and car lights. For current thin film solar cells technologies ITO alternatives are already in place and for next generation solar cells ITO substitution will be possible.

Low melting point alloys Indium has one of the lowest melting points of all metals and forms low melting point (i.e. room temperature to 156 °C) alloys with tin, silver, lead and ternary or quaternary combinations thereof. Indium alloys are therefore used in the electronics industry for soldering on temperature sensitive materials in moulded interconnect devices, flexible printed circuit boards or of temperature sensitive components in photonic applications, e.g. bonding of LEDs. Indium-lead is used for soldering on gold bond pads on printed circuit boards (PCBs) because of the better durability compared to tin-based alloys. Indium alloys are also highly ductile even at very low temperatures and are used to bond materials, (such as, quartz, glass and ceramics) with a large thermal expansion mismatch and in sealing of cryogenic equipment (e.g. liquefied gas production). Finally, indium is used to reduce mercury leakage in dental filling amalgams. Little effort has been put into finding alternatives for indium alloys, because they are used in relatively niche applications. There is range of tin-based alloys with zinc and bismuth used extensively for soldering and bonding in the electronics industry. However, tin-alloys have melting points down to 150 °C, which is the maximum in the melting point range of indium alloys. Lead-based alloys enable lower melting point, but these have recently been banned by the EU in the RoHS (Restriction of Hazardous Substances) directive. Hence, only for the least thermally sensitive applications are tin-based alloys good substitutes for indium alloys. Tin-alloys can also be used for bonding on gold, but indium alloys were specially developed as an alternative to the tinalloys. The so-called gold scavenging by bonding alloys resulting in destruction and failure of gold bond pads is much lower for indium alloys than for tin alloys. Substitution of indium alloys in cryogenic sealings by tin-based alloys is not possible, because tin alloys lose their ductility at low temperature. Alternative bonding/soldering technologies to metal alloys have been developed as part of the search for lead-free solders in the last decade. Silver-filled conductive adhesives have found limited industrial use, because of the high costs associated with the silver-filling. Nanoparticle pastes, using the melting point reduction of materials on the nano-scale are an emerging alternative bonding technology, but still have a time-to-market of at least 5 – 10 years. In general, market introduction of alternative bonding technologies is hindered by the huge installed base of soldering equipment and the strong focus on low-cost and high reliability manufacturing in the electronics industry. Indium-free dental fillings are widely used. Indium was specially introduced in dental filling amalgams to increase strength and reduce mercury leakage. Gallium based amalgams have also been developed, but are not preferred due to the criticality of gallium. Composite resin dental fillings are a general alternative to amalgam dental fillings. Although the durability of the composite fillings is marginally less, costs are slightly higher and application less easy composite dental fillings are a suitable alternative17. In conclusion substitution of indium alloys is currently possible in dental alloys, is possible for a number of low temperature bonding and soldering applications, but is not possible for cryogenic sealing.

In-compounds Indium-containing semiconductors are currently a minor use of indium. Semiconductor compounds of indium, specifically InP are used in high-power and high-frequency electronics, for example high tech mobile phones and wireless applications. Optoelectronics devices such as laser diodes, photodiodes and LEDs use InP, InGaAs and GaInN because of their high electron velocity compared to silicon and their direct bandgap. The In-based semiconductors are part of the multilayer stacks used as the active component in LEDs and laser diodes. GaAs and SiGe are alternatives to InP exhibiting similar properties

required for the high high-power and high-frequency electronics. However, both use other critical raw materials such as Ge and Ga. Zinc oxide (ZnO) has been investigated as an alternative semiconductor material in LEDs. However, the required p-type ZnO has limited stability making in not (yet) a feasible substitute. OLEDs are an emerging alternative lighting technology, but still lack the long-term stability to compete with solid state LEDs. Copper-indium-gallium-diselenide (CIGS) thin film solar cells are a growing application that is forecasted to attain a significant share (20%) of the fast growing photovoltaic market in the coming decades. CIGS is an III-IV-VI semiconductor with a band-gap ideal for conversion of sun light into electricity and, as a thin film solar technology, it holds the potential of lower manufacturing costs and better product integration compared to the state-of-the-art silicon wafer based solar modules. CIGS solar modules are manufactured on an industrial scale by around five companies world-wide. The industrial and academic CIGS community is aware of the criticality of indium, but opinions on the need for substitution vary. A one-to-one material substitution by copper-zinc-tin-selenide/sulphide (CZTS) has become a significant R&D theme in the recent years18. However, with a record efficiency (2013 figures) of only 11.1% compared to 20.4% for CIGS solar cells, commercial production of CZTS modules is not expected within the coming 10 years. Also due to the strong cost reduction in the last 3 years, silicon based solar modules are an obvious substitute for CIGS apart from its limitation of integration in electronic devices and the build environment. In conclusion, substitution of indium is at present mostly possible in semiconductor applications (highpower and high-frequency electronics applications and thin film solar cells) with the exceptions of optoelectronic devices (LEDs and laser diodes).

Summary Indium cannot be substituted in its main field of application, flat panel displays, without a loss of performance or the use of another indium containing component, but substitution is possible in most other applications albeit sometimes at higher costs.

Figure 3: Distribution of end-uses and corresponding substitutability assessment for indium. The manner and scaling of the assessment is compatible with the work of the Ad-hoc Working Group on Defining Critical Raw Materials (2010).

References 1 2 3 4 5 6

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Mikolajczak C, Murphy MD (2011) Sustainability of Indium and Gallium In the Face of Emerging Markets POLINARES Consortium (2012) Fact Sheet: Indium: POLINARES working paper n. 39 Phipps, G., Mikolajczak, C., Guckes, T. (2008) Indium and Gallium: long-term supply. Renewable energy focus 9(4), 58–59 Tolcin, A. C. (2013) Indium, in: U.S. Geological Survey (ed.) Mineral commodity summaries 2013, pp. 74–75 Bleiwas, D. (2010) Byproduct mineral commodities used for the production of photovoltaic cells. U.S. Geological Survey Circular 1365 NanoMarkets (2012) Transparent Conductor Markets 2012: REPORT # Nano-559. http://nanomarkets.net/market_reports/report/transparent_conductor_markets_2012. Accessed 7 August 2013 Metal Bulletin Indium Ingots MB free market Monthly Average in warehouse $ per kg: Latest Metal Prices Tracking and Comparison Tool. http://www.metalbulletin.com/My-price-book.html. Accessed 3 September 2013 U.S. Geological Survey (2013) Mineral Commodity Summaries 2013 United Nations Development Programme (UNDP) (2013) The 2013 Human Development Report – "The Rise of the South: Human Progress in a Diverse World" Yale Center for Environmental Law and Policy (YCELP) (2013) Downloads | Environmental Performance Index. http://epi.yale.edu/downloads. Accessed 26 July 2013 World Bank Group (2013) Worldwide Governance Indicators. http://info.worldbank.org/governance/wgi/sc_country.asp. Accessed 26 July 2013 Ad-hoc Working Group on defining critical raw materials (2010) Critical raw materials for the EU: European Commission Mikolajczak C (2014) Indium supply and demand. E-Mail. Accessed 3 December 2014 DiFrancesco, C., George, M., Carlin, J., Jr., Tolcin, A. (2012) Indium: Supply-Demand Statistics, in: U.S. Geological Survey Minerals Information O'Neill B (2010) Indium Market Forces: A Commercial Perspective Szyszka, B. (2011) Übersicht über die Einsatzgebiete und Anwendungen von TCOs, in: OTTI (ed.) Transparent leitfähige Schichten (TCO), pp. 81–124 Bharti, R., Wadhwani, K., Tikku, A., Chandra, A. (2010) Dental amalgam: An update. J Conserv Dent 13(4), 204–208. 10.4103/0972-0707.73380 Delbos, S. (2012) Kesterite thin films for photovoltaics: a review. EPJ Photovoltaics 3. 10.1051/epjpv/2012008

9. Magnesium Magnesium is the lightest structural metal. During the last decade, magnesium production in China has increased enormously. China's production was 250 000 Metric tons in 2002 and 675 000 Metric tons annually in 2011.1 This supply increase resulted in lower prices, leading to the closure of magnesium plants in the rest of the world. The last primary producer in Western Europe closed in 2002. There have been plans to start magnesium production in Europe over the past ten years, but continuing low prices have made it difficult to create a business case for it. Therefore, the production of magnesium is currently concentrated mainly in China.

Figure 1: Distribution of magnesium production2 and corresponding scores of the producing countries in the Human Development Index (HDI)3, Environmental Performance Index (EPI)4, and World Governance Indicators (WGI)5. Both the EPI and WGI are used to assess supply risks with the EU methodology for determining critical raw materials.6 CHN = China. After a price peak in 2009 the average price of magnesium metal has fallen down again. The average price of magnesium metal was 0.97 US$/kg in 2011*, a decline of 33% since 2009.2 Looking at a longer time frame from 2005 to 2012 it appears that the price is rising overall. During the period from 2011 and 2012 the price was stable and then started to decrease at the beginning of 2013.7 In Europe, Magnesium is mainly used in 3 different product categories; pure magnesium (>99,8% GHT) for aluminium alloying, magnesium alloys (