Responsible sourcing of critical metals

Abstract

Most critical raw materials, such as the rare earth elements (REE), are starting products in long manufacturing supply chains. It is difficult for consumers, buying cars or smartphones for example, to engage with the original mines and demand environmental and social best practice. Geoscientists can become involved in responsible sourcing because geology is related to environmental impact factors such as energy requirements, resource efficiency, radioactivity and the amount of rock mined. The energy and material inputs and emissions and waste from mining and processing can be quantified using life cycle assessment (LCA). Preliminary LCA studies for REE show little over all difference between ‘hard rocks’ such as carbonatites and easily leachable ion adsorption clays, mainly because of the embodied energy in chemicals used for leaching, dissolution and separation.