Indium: Key issues in assessing mineral resources and long-term supply from recycling

Indium and other geologically scarce metals are routinely integrated into green technologies and modern consumer electronics. The manufacture of solar cells and liquid crystal displays (LCDs) relies strongly on continued indium supply, yet very little research has been conducted to determine what total resources exist to meet future or even present needs. This paper provides an improved understanding of the nature of indium resources and the current and future production and supply of this critical metal through a summary of global trends in indium production and demand, and through a preliminary account of global code-based reporting of indium mineral resources. Authors also present an overview of the potential for indium extraction from mine wastes and recycled electronics using Canadian and Australian case studies. Our preliminary data suggest that considerable resources are likely to exist in a diversity of deposits globally, which have the potential to meet long-term demand for indium. However, it is clear that a secured future supply of this metal will require some shift of focus from conventional extraction practices. It will be necessary to revisit controls on the conversion of resources to reserves and to supply and the discovery of additional resources to replace those depleted by continuing production. The prospects for indium supply from mine wastes and recycled electronics are found to be substantial, and these sources warrant greater consideration given their probable environmental and social advantages over the discovery and development of new primary indium deposits.