Indium, a critical metal primarily used in electronics and renewable energy technologies, is facing increasing demand due to its essential role in products such as LCD screens, solar panels, and batteries. However, the traditional mining practices associated with indium extraction raise significant environmental concerns and sustainability challenges. In light of these issues, the concept of sustainable indium sourcing has gained traction, emphasizing the need for more responsible and efficient methods of obtaining this vital resource.
Indium is not typically found in standalone deposits; rather, it is often a byproduct of zinc, copper, and lead mining. This means that much of the indium supply is derived from the processing of these base metals. According to recent studies, significant quantities of indium are also present in mining wastes, such as tailings and slags, which can be viewed as secondary resources rather than mere waste. For instance, the Brunswick 6–12 and Heath Steele deposits in Canada have shown that substantial amounts of indium remain in tailings, with estimates indicating over 3,500 tons of indium metal in the Brunswick site alone. Such findings suggest that mine wastes could play a crucial role in future indium supply, thus contributing to sustainable sourcing.
The shift towards a circular economy presents another promising avenue for sustainable indium sourcing. Urban mining involves extracting valuable metals from electronic waste (e-waste) and other urban material stocks, thereby reducing reliance on traditional mining practices. Currently, only about 1% of global indium supply comes from end-of-life (EOL) recycled materials, while 25–50% is sourced from manufacturing scrap. This highlights a significant opportunity for improvement.
In Australia, for example, it is estimated that around 23.5 million old and unused mobile phones contain indium, yet the potential recovery from these devices remains underexploited. Although technical and economic challenges persist—such as low concentrations of indium in e-waste and the profitability of recycling—growing awareness of the environmental impact of electronics in landfills is driving increased focus on urban mining initiatives.
Despite the potential benefits of urban mining and recycling, several challenges must be addressed to enhance sustainable indium sourcing:
To move towards more sustainable indium sourcing, it is essential to consider the following strategies:
Sustainable indium sourcing represents a multifaceted challenge that requires a concerted effort from industries, governments, and communities. By tapping into the potential of mine wastes and urban materials, advancing recycling technologies, and fostering a circular economy, it is possible to reduce the environmental impact of indium extraction and ensure a more sustainable supply of this essential metal for future generations. As demand for indium continues to rise, embracing sustainable practices will be crucial in mitigating the ecological footprint of its sourcing while meeting the needs of a rapidly evolving technological landscape.
Werner, T. T., Mudd, G. M., & Jowitt, S. M. (2015). Indium: key issues in assessing mineral resources and long-term supply from recycling. Applied Earth Science, 124(4), 213–226. doi:10.1179/1743275815y.000000