(663c) Electrochemical Recovery of Rare Earth Elements from Neodymium-Iron-Boron Based Magnets Coupled with Iron Recovery

Rare earth elements (REE) have widespread applications in many commodities including wind turbines, electric vehicles, batteries, cell phone displays, etc. Hence, the market demand for REEs is expected to increase in the future. However, the shortage of natural deposits and environmental risks associated with mining create concerns for the sustainable supply of REEs. A prospective secondary source of these elements could be recycling REE-containing products once these reach their end of life (EOL). Neodymium-iron-boron (NdFeB) permanent magnets could be a prominent example of such a product. These magnets have 27-32% rare earth elements (REEs) (Nd, Pr, Dy), 67-73% iron, 1% boron, and other minor metals. These magnets have high energy density and are widely used in many applications, especially in wind turbines. Due to the increasing global wind power capacity, a large stockpile of EOL magnets is predicted to be available in the near future.

Researchers have developed several processes including the hydrometallurgical and pyrometallurgical route for recycling NdFeB magnets. However, recovering iron, the major component of these magnets, poses a significant challenge. The conventional hydrometallurgical and pyrometallurgical recovery processes extract REEs leaving behind a solid waste normally as Fe(III) hydroxide/ Fe(III) oxide hydroxides, or as jarosite.

The Institute for Sustainability & Circular Economy at Texas Tech University has developed an electrochemical recycling route for NdFeB magnets. A novel method for REE recovery via acid leaching coupled with the electrowinning of iron will be presented. The following aspects will be included: the REE extraction process, the effect of iron speciation on REE recovery, and iron electrowinning as a means of metallic iron recovery from acid waste.