In the Appalachian coal region, researchers are considering turning toxic waste into a treasure trove. The dirt left behind by the mine is a source of rare earth elements.
Rare earths are the most important of the 18 elements that make up everything from smartphones and electric vehicles to fluorescent bulbs and lasers. With global demand skyrocketing and China having a near-monopoly on rare earth production — the United States has only one active mine — there is a lot of interest in finding alternative sources, such as rappelling recycling.
Science News headlines in your inbox
Headlines and summaries of the latest Science News articles, delivered to your email inbox every Thursday.
Thank you, because I want up!
I’m having trouble subscribing to you.
Extracting rare earths from waste coal offers a two-for-one deal: By recovering the metals, you also help clean up pollution.
Long after my account closes, it can leave a dirty legacy. When any rock is exposed to excess metals of air and water, sulfuric acid forms and pulls the heavy metals out of the rock. This acidic mess can pollute waters and harm wildlife.
Recovering rare earths from said acid mine aquifers is not one way to satisfy the rising demand for metals, acknowledges Paul Ziemkiewicz, director of the Morgantown Water Institute in West Virginia. But it shows many benefits.
Unlike ore mined from typical rare earth mines, alluvium is rich in the most essential rare earth elements. Plus, the extraction from my acid mine also doesn’t generate radioactive waste, which is typically a product of rare earth mines, which often contain uranium and thorium around the rare earths. And from a practical point of view, the existing resources to take care of acid mine irrigation must be used to collect rare earths for processing. “Theoretically, you could start tomorrow,” Ziemkiewicz says.
From the few hundred sites already treating acid mine drainage, nearly 600 metric tons of earth elements and cobalt — another in-demand metal — could be produced annually, Ziemkiewicz and colleagues estimate.
Currently, a pilot project in West Virginia is taking material from an acid mine wastewater treatment site and extracting it and containing it in rare earths.
If such a device proves feasible, Ziemkiewicz envisions a future in which cleanup sites will haul their rare earths to the middle of the process and send the components to be disassembled. Economic analyzes suggest that this is not a get-rich scheme. But, he said, it would be enough to cover the costs of treating my acid drainage.
#Rare #earth #elements #extracted #coal