Byproduct metals and rare-earth elements used in the production of light-emitting diodes—Overview of principal sources of supply and material requirements for selected markets

Abstract

The use of light-emitting diodes (LEDs) is expanding because of environmental issues and the efficiency and cost savings achieved compared with use of traditional incandescent lighting. The longer life and reduced power consumption of some LEDs have led to annual energy savings, reduced maintenance costs, and lower emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides from powerplants because of the resulting decrease in energy consumption required for lighting applications when LEDs are used to replace less-energy-efficient sources. Metals such as arsenic, gallium, indium, and the rare-earth elements (REEs) cerium, europium, gadolinium, lanthanum, terbium, and yttrium are important mineral materials used in LED semiconductor technology. Most of the world's supply of these materials is produced as byproducts from the production of aluminum, copper, lead, and zinc. Most of the rare earths required for LED production in 2011 came from China, and most LED production facilities were located in Asia. The LED manufacturing process is complex and is undergoing much change with the growth of the industry and the changes in demand patterns of associated commodities. In many respects, the continued growth of the LED industry, particularly in the general lighting sector, is tied to its ability to increase LED efficiency and color uniformity while decreasing the costs of producing, purchasing, and operating LEDs. Research is supported by governments of China, the European Union, Japan, the Republic of Korea, and the United States. Because of the volume of ongoing research in this sector, it is likely that the material requirements of future LEDs may be quite different than LEDs currently (2011) in use as industry attempts to cut costs by reducing material requirements of expensive heavy rare-earth phosphors and increasing the sizes of wafers for economies of scale. Improved LED performance will allow customers to reduce the number of LEDs in automotive, electronic, and lighting applications, which could reduce the overall demand for material components. Non-Chinese sources for rare earths are being developed, and some of these new sources are likely to be operational in time to meet increasing demand for rare earths from the LED sector. Because most LED component production and manufacturing occurs in Asia and many LED producers have established supply contracts with Chinese producers of rare earths, a significant amount of the metallic gallium, indium, and the rare earths used for LED production will likely continue to come from Chinese sources at least for the next 5 years; however, a greater amount of these materials are now being processed in Japan, the Republic of Korea, and Taiwan. As non-Chinese sources of rare earths come into production, these new mines are likely to be sources of light REEs, but China will likely remain the leading source of supply for the heavy REEs suitable for use as LED dopants and phosphors at least for the next few years. Increased research in the development of phosphors that use smaller amounts of or different REEs is intended to reduce dependence on rare earths from China. Supply disruption of rare earths and other specialty metals could take place if China's specialty metal exports are redirected to domestic markets. The cost of recovery is high and the lifespan for LEDs is comparatively long; thus, the LED waste volume was low in 2010, and few LEDs were recycled. The minute metal content of LEDs leads to a high cost for recovery, so recycling of LEDs outside of electronic waste is unlikely in the near term, although some LED producers are evaluating recycling options. Recycling of metals from LEDs in electronic waste is possible if the costs of recovering metals are justified by demand and metal prices.