Rare Earth magnets are ubiquitous is electronic devices. They are found in everything from computer hard drives to headphones, but they have been difficult to recycle. Researchers have now developed a new method of reusing the class of materials.
These substances are, as the name suggests, difficult to locate and obtain. Mining and refining the materials is difficult, expensive and highly-damaging to the environment.
Dysprosium and Neodymium are two elements used in the manufacture of many small, powerful magnets used in modern electronic devices.
"Neodymium magnets can't be beat in terms of their properties. They give you the strongest amount of magnetism for the smallest amount of stuff and can perform at a range of temperatures," Eric Schelter of the University of Pennsylvania said.
Due to the difficulty and expense of processing rare Earth materials, this new recycling method makes reusing these materials much cheaper and easier than obtaining raw elements. Unlike current technologies, this new process utilizes standard laboratory equipment, and recycling takes places in a short period of time at room temperatures.
Various electronic applications require rare Earth materials to be combined in different ratios. Due to this requirement, elements of rare Earth magnets need to be separated before being recombined for new purposes.
"We have designed a way to separate the two metals by selectively dissolving the neodymium in a solution and leaving behind the dysprosium as a solid. This quick and easy method has allowed us to separate equal mixtures of the metals into samples that are 95 percent pure," Justin Bogart, a graduate student at the University of Pennsylvania said.
Liquid-liquid extraction is currently used to recycle rare Earth materials from used magnets. The process involves melting the objects and filtering the component materials one by one. In order to obtain the purity required for manufacture of the small, powerful magnets, filtering must take place thousands of times.
The new process involves the use of a ligand, a molecule that binds to metals, which is added to a powdered mixture of rare Earth elements. The ligand binds to the atoms in such a way that the solubility of neodymium and dysprosium changes, allowing chemists to separate the materials using common laboratory chemicals.
Liquid-liquid extraction can take weeks to complete and requires highly-specialized, costly equipment. This new method is inexpensive and can be completed in just five minutes. This new development could allow small-scale recycling centers to economically recycle rare Earth waste products.
Further development will study how different ligands could be utilized to recycle other rare Earth elements, such as those used in compact fluorescent light bulbs.
Development of this new method of recycling rare Earth materials was detailed in Angewandte Chemie, International Edition.