Waste not

Researchers at Yale University have assessed the “criticality” of all the metallic elements, indicating which might become more difficult to source in the coming years. Factors contributing to criticality include high geopolitical concentration of primary production (over 90% of the rare Earth metals comes from China); lack of available substitutes and political instability (a major source of tantalum is the war-ravaged Democratic Republic of the Congo). Another report has highlighted sewage as a source for extracting and recycling metals.