User:Hxu459/Rare-earth element

Lead
The rare earth elements (REEs) are vital to modern technologies and society and are amongst the most critical of the critical elements. Despite this, typically only around 1% of REEs are recycled from end-products, with the rest deporting to waste and being removed from the materials cycle. Recycling and reusing REEs play an important role in the world currently for the development of efficient and high-tech and environment friendly products.

Potential methods
REEs recycling and reuse have been increasingly focused on in recent years. The main concerns include environmental pollution during REE recycling and increasing recycling efficiency. A study suggests that, along with previously established pollution mitigation, a more circular supply chain would help mitigate some of the pollution at the extraction point. This means recycling and reusing REEs that are already in use or reaching the end of their life cycle. A study published in 2014 suggests a method to recycle REEs from waste nickel-metal hydride batteries, demonstrating a recovery rate of 95.16%. Rare-earth elements could also be recovered from industrial wastes with practical potential to reduce environmental and health impacts from mining, waste-generation and imports if known and experimental processes are scaled up. A study suggests that "fulfillment of the circular economy approach could reduce up to 200 times the impact in the climate change category and up to 70 times the cost due to the REE mining." In most of the reported studies reviewed by a scientific review, "secondary waste is subjected to chemical and or bioleaching followed by solvent extraction processes for clean separation of REEs."

There are essentially two options being considered for a secure supply of REEs: from primary resources (old mines or new deposits, ocean bed sediments, coal ash, etc.) and from secondary resources (electronic and industrial waste). For example, it is estimated that about 50 million metric tons of e-waste are disposed in landfills all around the world each year. However, only 12.5% of e-waste is currently being recycled for all metals.The e-waste contains significant concentrations of REEs. E-waste contains a significant concentration of REEs, and thus is the primary option for REE recycling.

Challenges
For now, there are some obstacles during REE recycling and reuse. One big challenge is REE separation chemistry. Specifically, separation and purification of individual REE is challenging due to similarities in their chemical properties. To develop other sources of REE and reduce the environmental impact of their isolation, there is an apparent need for new separation technologies which are capable of reducing the cost of industrial-scale REE separations and recycling. In this context, Department of Energy’s Critical Materials Institute (CMI) have developed a method of using Gluconobacter bacteria comsuming sugars to produce acids to dissolve and separate REE from shredded electronics.