CAS Guangzhou Institute of Geochemistry has developed a greener and more efficient mining technique to recover rare-earth elements (REEs) from weathering crusts, revealing new paths for the sustainable harvest of natural resources. Ion-adsorption rare-earth deposits are a primary repository of heavy REEs. These deposits are currently mined via the ammonium-salt-based leaching technique leading to severe environmental damage with a low recovery rate. A research team led by He Hongping has designed an innovative REE mining technique called electrokinetic mining (EKM), which enables a green, efficient and selective recovery of REEs from weathering crusts. The feasibility of EKM was demonstrated by He’s team via laboratory-scale, scaled-up and field-scale experiments last year. Now, they have launched the first industrial trial and successfully built a demonstration project with 5,000 tonnes of soil. Compared with conventional techniques, the EKM technique achieves a 30-percent increase in recovery rate, an 80-percent decrease in leaching agent usage, a 70-percent decrease in mining time, a 70-percent reduction in metallic impurities in the obtained REE leachates and a 90-percent decrease in ammonium emissions.
CAS team develops electrokinetic mining for rare-earth elements