Extracting rare earths might be crucial to our ability to transition to sustainable energy sources. And at what expense?

Extracting rare earths might be crucial to our ability to transition to sustainable energy sources. And at what expense?

Extracting rare earths might be crucial to our ability to transition to sustainable energy sources. And at what expense?

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ISRDO Team 12 Jan, 2023 - in Earth sciences
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  • uranium
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For a century before, miners extracted precious metals from those peaks. However, the soldiers were seeking a different type of treasure: uranium. After WWII ended, the globe immediately plunged into the Cold War. As part of its nuclear arsenal, the United States need uranium. It became critical to the country's safety to mine domestic resources.

The three explorers had spent weeks looking for their fortune, and they finally seemed to have found it. Instruments picked up very high levels of radioactivity in veins of brownish-red ore in a rocky outcrop in the Clark Mountains of California. Bastnaesite, a mineral containing fluorine, carbon, and 17 unusual elements known as rare earths, was ultimately identified as the brownish-red substance that had first been thought to be uranium. Geiger counters had also been activated by the presence of radioactive thorium in the ore.

Despite this setback, the prospectors saw potential in their bastnaesite and sold their claim to the Molybdenum Corporation of America, which would eventually become Molycorp. The business was considering starting a rare earths mining operation. Cerium, for instance, became the foundation of a glass-polishing powder, while europium added luminosity to newly developed colour television displays and fluorescent lighting in the middle of the 20th century.

For the next several decades, until two pressures got too great, this location—later renamed Mountain Pass mine—served as the world's primary source for rare earth elements. China began actively mining rare earths in large quantities and selling them at reduced costs by the late 1980s. A series of hazardous waste accidents at Mountain Pass stopped operations at the faltering mine that year, 2002.

However, it wasn't the last chapter. Mountain Pass was forgotten until the 21st century's green technology movement revived interest in rare earth mining there.

Many carbon-neutral technologies, as well as a wide variety of contemporary day instruments, now need rare earths as a crucial component in their production. Small, high-performance permanent magnets made from these components constitute the backbone of devices as varied as smartphones, wind turbines, electric cars, and more.

In February 2021, the government of President Joe Biden declared that the mining of domestic sources of rare earth elements was an issue of national security.

While we do find rare earths in the Earth's crust, they are typically found in low amounts. Additionally, according to Julie Klinger, a geographer at the University of Delaware in Newark, the ore itself is not worth very much without the sophisticated, sometimes ecologically dangerous processing needed in transforming the ore into a useful form. This has left a lasting environmental impact on the rare earth mining sector.

When rare earths are extracted, large open pits are dug, which may cause pollution and damage to local ecosystems. Wastewater ponds used in the mining industry can get contaminated with acids, heavy metals, and radioactive substances if regulations are lax. It takes a long time, a lot of water, and maybe some harmful chemicals to process the raw ore into a form that can be used to build magnets and other technological components.

Michele Bustamante, a sustainability researcher at the Natural Resources Defense Council in Washington, D.C., says, "We need rare earth elements... to assist us with the transition to a climate-safe future." Nonetheless, "everything that we do while we're mining is impactful ecologically," Bustamante explains.

However, Thomas Lograsso, a metallurgist at the Ames National Laboratory in Iowa and the head of the Critical Materials Institute, a Department of Energy research facility, thinks that there are techniques to lessen the impact of mining. Researchers are looking at enhancing the efficiency of rare earth element separation, which may help reduce the quantity of harmful waste produced during the ore processing. Mining isn't the only way to get rare earth elements, however; scientists are also looking at extracting them from coal waste and recycling obsolete gadgets.

Lograsso emphasises the importance of the mining industry's participation in this study. Change requires investment, which mining corporations must be ready to provide. So that "we're not here producing solutions that nobody actually wants," he adds, "we want to make sure that the research and innovations that we undertake are driven by industry demands."

Klinger is cautiously confident that if these measures are broadly implemented, the rare earth mining business may become less harmful and more sustainable. She claims that "many profits come from the low-hanging fruit." Insulation enhancements, although relatively inexpensive, may significantly cut down on the amount of fuel needed to achieve the high temperatures necessary for particular procedures. That whatever you are able to accomplish, you do.

Rare-earth mining's toll on the environment

Ivanpah Dry Lake is a wide, flat, and glistening basin located between the craggy hills of California's Clark range and the Nevada border. About eight thousand years ago, the valley had a constant supply of water. Like many playas in the Mojave Desert, the lake is temporary today, appearing briefly after a heavy downpour and subsequent flash flooding. Species of desert tortoises and desert flora like Mojave milkweed are found in this starkly gorgeous region.

The Ivanpah Dry Lake served as a settling pond for wastewater pumped in from Mountain Pass from about 1984 to around 1998. The wastewater was a byproduct of a chemical process used to concentrate rare earth elements in the mined rock, making it more attractive to businesses who could subsequently extract those elements to produce specialised goods. The mine's effluent was sent through an underground conduit to evaporation ponds in and around the dry lake bed, which was located approximately 23 kilometres distant.

Over the course of several years, the pipeline suffered many breaks. The valley was contaminated with radioactive thorium from at least 60 different incidents. Locals and tourists to the neighbouring Mojave National Preserve were worried that they would be exposed to enough thorium to raise their chance of developing lung, pancreatic, and other cancers, according to federal authorities.

After acquiring Molycorp in 1977, Unocal Corporation was fined and settled for more than $1.4 million in 1997 for failing to clean up the leak. The raw ore's chemistry processing came to a standstill. Shortly after that, mining activities came to a halt.

Another ecological catastrophe was developing halfway across the planet. Since the 1990s, China has been the primary source of rare earth elements on the market, accounting for 80% to 90% of the total. In 2019, 45 percent of the world's rare earths came from only one place: the huge Bayan Obo mine in Inner Mongolia.

Around half the size of Walt Disney World in Florida, Bayan Obo covers an area of about 4,800 hectares. In addition, it is a very polluted area. After years of clearing land to mine for mining, the Gobi Desert has advanced southward into a region that was already vulnerable to desertification.

Officials in the adjacent city of Baotou noticed in 2010 that radioactive mining waste comprising arsenic and fluorine was being dumped on farms, into local water sources, and into the Yellow River. Toxic dust and gases obscured the sky. Residents cited issues with motion sickness, dizziness, headaches, and arthritis. Some showed evidence of brittle bones, indicative of skeletal fluorosis, while others showed signs of skin lesions and discoloured teeth, indicative of extended exposure to arsenic, as reported by Klinger.

China's State Council said in 2010 that the country's rare earth sector was creating "serious harm to the natural environment." The mining process contributed to "the loss of flora and contamination of surface water, groundwater, and agriculture" due to the emission of heavy metals and other contaminants. Because to "excessive rare earth mining," the council said that landslides and polluted waterways occurred.

As a result of these increasing environmental catastrophes and worries that it was losing its rare earth resources too quickly, China reduced its export of the elements by 40% in 2010. These new restrictions caused prices to skyrocket and sparked global worry that China had too much of a monopoly on these strategic materials. That resulted in increased funding for rare earth mining in other areas.

Only India, Brazil, and Malaysia produced any significant quantities of rare earths in 2010. Lynas, a mining firm, brought their new mine in Western Australia online in 2011. The business excavated ancient lava that had been petrified inside Mount Weld.

Saleem Ali, an environmental planner at the University of Delaware, claims that Mount Weld did not have anything like the same environmental effect as witnessed in China because of its isolated location and the mine's much smaller scale compared to Bayan Obo. In the meanwhile, the United States was keen to secure its own rare earths supply, and Mountain Pass remained the best option.

Complexities of Rare-Earth-Element Extraction

In the middle of an August morning, 800 metres broad, and up to 183 metres deep, Sloustcher stands at the brink of the Mountain Pass mine. An inspiring scene, and a perfect vantage point from which to convey a vision for the future. He describes the numerous facilities, including those used for crushing and grinding the ore, chemically treating the powdered rocks to remove as much impurity as possible, and squeezing the water out of the waste before depositing it in lined ponds.

The final product is a rare earth oxide ore with very high concentrations of the elements, although it is not yet magnetic. It has a three-part strategy, from "mine to magnet," to "return the whole rare earth supply to the United States," Rosenthal said. First, in 2017, work resumed on mining, crushing, and concentrating the ore. The second phase will conclude with the chemical separation of the rare earth elements. The third phase, he believes, will include manufacturing magnets.

CITATIONS

R. C. Chapleski, Jr. et al. Improving Rare-Earth Mineral Separation with Insights from Molecular Recognition: Functionalized Hydroxamic Acid Adsorption onto Bastnäsite and Calcite. Langmuir. Vol. 38, April 20, 2022, p. 5439. doi: 10.1021/acs.langmuir.1c03422.

U.S. Geological Survey. 2022 Final List of Critical Minerals. Published February 22, 2022.

J. M. Klinger. Rare-earth frontiers: From terrestrial subsoils to lunar landscapes. Cornell University Press, 2017.

S.H. Ali. Social and environmental impact of the rare-earth industries. Resources. Vol. 3, February 13, 2014, p. 123. doi: 10.3390/resources3010123.

A. L. Buck. A history of the Atomic Energy Commission. U.S. Department of Energy. Published July 1983. 

J. C. Olson et al. Rare-Earth mineral deposits of the Mountain Pass district, San Bernardino County, California. U.S. Geological Survey Professional Paper 261. Published 1954. https://doi.org/10.3133/pp261.

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