Huge volumes of rock that would normally end up in landfill could be processed into a valuable exotic metal, researchers at a multinational mining giant have said.
A research team at Rio Tinto is finding commercially viable ways to extract lithium from waste rock at one of its Californian mines, so the metal used in batteries can be sold to North America’s fast-growing electric vehicle manufacturing sector.
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Borates, which are used to manufacture soaps and cosmetics, and other types of tailings have been accumulated after nearly 100 years of production at the Mojave Desert, about 195 km north of Los Angeles.
Rio is so confident the effort could be profitable, it is investing US$10 million (A$14.5M) in constructing a pilot plant to extract the lithium through a special heat-and-leaching process that requires heating a kiln up to 949C.
“The material being used has already been mined, so this will be a low-energy option for the production of lithium,” Rio chief executive of energy and minerals Bold Baatar told Reuters.
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The pilot project will initially produce about 10 tonnes annually. If successful, Rio will consider spending US$50M (A$72.9M) to build an industrial-scale plant that can process 5000 tonnes of lithium each year.
Rio said this facility could become the largest lithium producer in the nation with customers like Panasonic, Tesla and other electric product manufacturers.
Mining expansion urged
US politicians and authorities have urged the industry to expand domestic exploration of strategic minerals used to make electric vehicle batteries and other high-tech equipment. At the moment China is the world’s largest producer and consumer of many of these minerals.
Other companies are also developing lithium projects including Lithium Americas, Standard Lithium, Texas Mineral Resources, Piedmont Lithium and ioneer, which is developing a lithium project in Nevada that also contains a large concentration of borates.