A process that recovers rare-earth elements from ‘urban mining’

Electrochem Technologies & Materials Inc. (Montreal, Canada; www.electrochem-technologies.com) has recently patented a process for recovering rare-earth elements (REEs) from mercury phosphor powders — a byproduct from recyclers of fluorescent lamps and light bulbs. This technology offers a sound and profitable alternative for the production of REEs compared to the mining of low-grade ores, which requires large tonnage operations, says company president, Francois Cardarelli. Such mining operations have both high operating and capital costs, and unavoidably produce radioactive wastes, he says. In contrast, Electrochem’s “urban mining” technology can secure the supply of affordable REEs, especially coast-to-coast in North America, where several tons of REE-rich phosphor powders are generated monthly by recyclers. Moreover, because of the limited number of REEs present and the very small-scale operation required (50 to 300 kg/wk of mercury-phosphor dust), existing and well-known REE separation technologies can be used directly downstream without impacting the operating costs significantly, says Cardarelli. In Electrochem’s process (flowsheet) Hg is first removed by vacuum retorting. The Hg-free dust is…