Millions of tons of charcoal ash, resulting from the burning of the most polluting fossil fuel on the planet, are deposited in lagoons and landfills, and may contaminate watercourses and pollute the soil . These toxic waste, however, They can also be a treasure of elements of rare land needed to boost the world towards clean energy.
Scientists analyzed charcoal ash of power plants in the United States and found that they may contain up to 11 million tons of elements of rare land – almost eight times the amount of the US has in national reserves – worth about US $ 8.4 billion (approximately R $ 47.5 billion) according to a recent survey led by the University of Texas in Austin.
The so -called rare lands are a set of metal elements, with names like Scandio, Neodymium and Itrian which exist in the nucleus of the earth. They play a crucial role in clean technologies, including electric vehicles, solar panels and wind turbines.
Recent research offers a huge potential source of national rare land elements without the need for new mines, said Bridget Scanlon, study author and researcher at Jackson School of Geosciences at the University of Texas. “This really exemplifies the mantra ‘from the trash to the treasure,” she said. “We are basically trying to close the cycle and use the trash and recover resources contained therein.”
Despite the name, these metals are not rare in nature, but they can be difficult to extract and separate from the surrounding ore, so that the demand exceeds the offer.
As the world moves away from the fossil fuels that heat the planet, more rare land will be necessary . Demand for these metals should increase current levels by 2040, according to the International Energy Agency.
However, US offer remains small. Its only large -scale rare land mine is Mountain Pass, California. The country currently imports more than 95% of its rare land elements, the vast majority of which come from China, which represents security and supply chain problems.
“We need to improve the situation,” Scanlon told CNN . This is why there was a movement to seek unconventional sources of rare land, she said, “and one of these sources is coal and its derivatives.”
Coal ashes contain relatively low concentrations of rare land elements compared to what can be extracted directly from underground deposits. The advantage is that they are easily available. About 70 million tons of charcoal ash are produced annually in the US.
“There are huge volumes of this substance across the country. And the initial extraction process… is already resolved to us,” said Davin Bagdonas, co -author of the study and researcher at the University of Wyoming.
The study concluded that the origin of coal determines how directly the extraction of rare lands would be.
The coal ashes of the Apalach Basin contain the largest amounts of elements of rare lands, but Only 30% can be extracted . The charcoal ash of the Powder River basin, which covers Wyoming and Montana, have the lowest average concentration of elements, but more than 70% can be extracted.
The process of extraction of charcoal ash can be expensive, said Paul Ziemkiewicz, director of the Western University of Virginia University Hydric Research Institute, which did not participate in the study. Mining costs need to be considered regarding the amount of product that can be recovered, he reported CNN.
“Strong acids and bases are necessary to extract elements of rare land. Both are expensive,” said Ziemkiewicz. Western charcoal ash may contain higher concentrations of alkaline minerals, he added, which would increase costs as alkalinity neutralizes acid.
The more chemicals are needed in the process, the greater the potential environmental impacts.
Elements of rare land also represent only a small proportion of coal ash, Ziemkiewicz added, so their extraction would “not change the volume that requires disposal and storage.” Coal ashes contain contaminants such as mercury, arsenic and lead, which makes them a very risky waste flow.
The study authors, however, suggest that the value of rare land metal extraction can be used to compensate for improvement costs as coal ash are stored and managed.
In April, the Biden government announced an investment of $ 17.5 million in projects to extract rare land from coal and its waste.
The financing “will increase our national security while helping to rebuild the manufacturing sector of the United States and revitalize energy and mining communities across the country,” said Energy Secretary Jennifer Granholm in a statement at the time.
Some expressed concerns that turning charcoal ashes into something valuable could be used to press for more coal, the most polluting of fossil fuels that heat the planet.
It’s not something Scanlon is very worried. “We will use, largely, legacy waste,” said Scalon. Currently, there are over 2 billion tons of charcoal ash stored in the US, according to the Energy Department. “There is no evidence that future dependence of coal ash as a raw material for critical materials will encourage coal energy,” a DOE spokesman said.
The broader goal is to find ways to get a variety of coal products, as well as rare lands, said Scanlon, to extract value of it without burning it.
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This content was originally published in rare clean energy metals are found in coal residues on the CNN Brazil website.
Source: CNN Brasil
Charles Grill is a tech-savvy writer with over 3 years of experience in the field. He writes on a variety of technology-related topics and has a strong focus on the latest advancements in the industry. He is connected with several online news websites and is currently contributing to a technology-focused platform.
