Waste electrical and electronic equipments (WEEE or e-waste) are an important source for rare earth elements (REEs). Among various type of WEEE, NdFeB magnets are known for their high content of neodymium (Nd) and dysprosium (Dy). Recovery of REEs from NdFeB magnets is of prime interest for the industry to meet the ever-growing demand for REEs. In this study, some physical and hydrometallurgical approaches including demagnetization, grinding, screening, leaching, precipitation and extraction have been adopted to study the Nd and Dy recovery from spent NdFeB magnets. Various inorganic (HCl, HNO₃, H₂SO₄ and aqua regia) and organic reagents (acetic acid and oxalic acid) were tested as lixiviants for leaching of the magnets. As a new approach, the recovery of Nd and Dy in the leaching solution was tested by eliminating the iron by a solution purification process involving precipitation of ferric iron in solution as hydroxide and solvent extraction with ionic liquids (ILs). The comparative studies demonstrated that the extraction efficiency of di-2-ethylhexyl phosphoric acid (D2EHPA) was higher than trihexyltetradecylphosphonium chloride (CYPHOS® IL101) after leaching stage. Nd and Dy were successfully extracted with complete recovery from the optimized system.

Increasing demand for low carbon technologies and renewable energy sources requires our resources and economies to be circular. Many countries agree that the responsible consumption, production, and recycling of rare-earth-containing products is essential as a way to achieve the sustainable development goals also set out in the European Green Deal. Sustainable sourcing is targeted with carefully designed roadmap for cost efficient REE production from end-of-life products (EoLs) in addition to mining activities as providing primary sources. Hydrometallurgical methods, such as roasting, leaching, precipitation, crystallization, solvent extraction, and ion exchange includes fast developing, selective, eco-friendly, and cost-effective technologies especially for the extraction of REEs. This article provides an overview of primary and secondary resources and summarizes presents case scenario of studies carried out on the use of some promising methods, which could serve as an economical means for recovering REEs.