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Recovering Rare Earth Elements from Coal Ash for Clean Energy Technologies
Context:
- Researchers are exploring coal ash, a byproduct of coal-fired power plants, as a potential new source of Rare Earth Elements (REEs).
- This study specifically investigates coal ash from plants in Alberta and Saskatchewan, Canada.
Key Highlights:
- REEs are crucial for technologies needed in the transition to green energy, including electric vehicles and other clean energy solutions.
- REEs are not particularly rare but are found in large deposits in a few locations, mostly in China. Extracting them is challenging.
- Using X-ray beamlines at the Canadian Light Source (CLS) at the University of Saskatchewan, the team analysed coal ash samples to locate and study REEs, particularly yttrium.
- REEs, including yttrium, were found concentrated in specific minerals within the ash, such as silicates and phosphates (e.g., xenotime), which are stable during coal combustion.
- The recovery of REEs from coal ash not only helps manage waste but also contributes to the supply of essential materials for sustainable energy solutions.
Significance:
- Recovering REEs from coal ash could provide a short-to-medium-term source of these critical metals, potentially faster than developing new mines, which can take up to 17 years from exploration to production.
- This method supports a circular economy by turning waste into a resource, reducing environmental liabilities associated with coal ash, and providing materials needed for clean energy technologies.
Implications:
- The presence of REEs in stable minerals like xenotime suggests that existing extraction processes might be adapted for coal ash.
- While the concentration of REEs in coal ash is not very high, the large volume of ash and the even distribution of REEs can simplify extraction compared to traditional mining.
REEs
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- A group of seventeen metallic elements consisting of the fifteen lanthanides on the periodic table, plus scandium and yttrium.
- They have properties that include magnetic, phosphorescent, and catalytic attributes, making them indispensable in many high-tech and green technologies.
Benefits:
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- Consumer Electronics: They are used in cellphones, computer hard drives, and flat-screen monitors.
- Medical Technologies: MRI machines, laser scalpels, and certain cancer drugs rely on REEs.
- Defence Applications: Satellite communications, guidance systems, and aircraft structures depend on REEs.
- Green Technologies: Wind turbines and electric vehicles use REEs to improve efficiency and reduce carbon emissions.