Rare Earth Materials Recovery System

The Rare Earth Materials Recovery System (REMRS) recovers neodymium and related rare earth elements from permanent magnets of variable composition recycled from hard disk drives (HDD), motors, generators, and other industrial, military, and consumer products. The REMRS recovers rare earth oxides as high-quality feed stock to support manufacture of new high performance magnets. Fresh materials are required to counteract the gradual degradation in magnetic properties that takes place after multiple direct recycling steps. In REMRS, an initial low-temperature, low-pressure hydrogen decrepitation step is carried out to demagnetize, produce fine particles, and release surface coatings. A regenerable aqueous ammonia/ammonium carbonate solution is then used to decompose permanent magnet alloy compositions at low temperature and pressure into their iron, neodymium/dysprosium, and boron constituents to enable domestic recovery and recycling for production of new materials. After selective recovery of constituents from the extraction solution, ammonia and carbon dioxide are recycled to the process. This novel application of an ammonia/ammonium carbonate extraction process avoids the costs and environmental impacts of alternate aqueous treatments using strong sulfuric, hydrochloric, nitric, or hydrofluoric acids. The extraction process is typically carried out at temperatures below about 60C and at low pressure in vessels constructed of stainless steel.