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The world’s increasingly electronic and green economy rests on 17 metals known as rare earths, which are becoming increasingly scarce, especially since political turmoil has slowed production out of Myanmar, the world’s third-largest exporter.
Since 2020, the price of the lithium carbonate used to make batteries for everything from smartphones to smart cars has shot up more than 400 percent. The cost of praseodymium, essential for the magnets in electric motors for electric vehicles and wind turbines, has almost doubled, and terbium oxide, needed for LED lights and lasers, is more than 75 percent more expensive.
Rare earths aren’t actually rare; all 17 are more abundant than gold. The metals are just difficult to extract and purify: they tend to be widely scattered in small deposits and often are mixed in with radioactive materials, meaning the water used to mine and process them has to be disposed of in special and costly ways.
China now dominates the world’s rare earths market.
Chemists at Rice University have come to the rescue by finding a new source of these critical materials: trash.
A few years ago, engineers there developed a special heating process to turn coal, coke, and any kind of waste carbon into graphene, those sheets of carbon one atom thick that have been found to be not only the world’s strongest material, but also excellent conductors of heat and electricity.
Now the same lab has applied its heating process to recover rare earths from coal ash, electronic waste, and residue left over from processing bauxite into aluminum.
Conventional processes to reclaim valuable materials from these wastes involves a time-consuming process of soaking them in strong acids, creating a slurry of toxic waste.
In contrast, the Rice process flash-heats the wastes to 3,000° C, or more than 5,400° F, in a second, turning them into easily dissolvable compounds that need 150 times less acid to extract twice the amount of good stuff from the same amount of trash as the old way can.
TRENDPOST: The process means that no industrialized country needs to be entirely dependent on foreign sources or environmentally damaging processes to boost their supplies of rare earths.
This easier, faster way of reclaiming rare earths will be adopted quickly. Rice already is commercializing its heating process for making graphene; little adaptation is needed to apply it to the millions of tons of coal ash, bauxite residue, and discarded computers and smartphones the U.S. alone creates each year.