Treasures in the Mud

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Several weeks ago, Japanese researchers announced the discovery of a treasure trove off the coast of Minamitori Island: a tremendous amount of rare-earth minerals. As this article notes, rare-earth elements—17 in all, including the lanthanides plus scandium and yttrium—are much in demand for a growing number of high-tech applications like smartphones, superconductors, camera lenses and smartphone screens, hybrid vehicles, missile systems, and radar devices.

Despite their name, most rare-earth elements, or REEs, aren’t exactly rare; they’re fairly abundant but usually widely distributed, making them harder to get at than more concentrated substances. The one large mine in the US has been beset by regulatory and environmental problems, and as uses for rare-earth elements have expanded and demand has increased, the US has been importing more of these elements. Currently, the world’s biggest supplier of rare-earth elements is China, which produces something like 90%.

Japan’s discovery could change that, but there are still some hurdles to overcome. The roughly 16 million tons of mud containing the elements is deep within the ocean nearly 800 miles from Japan’s coast. The refining process is also difficult and expensive. As this MIT article explains, “The traditional method of extracting pure REEs from mined material is called the solvent-exchange method, and consists of first crushing the rock into smaller chunks and then grinding it into a fine dust. Unwanted materials (largely iron oxide minerals and carbonate minerals) are removed using various separation methods, leaving behind an ore of REEs and radioactive material, which are then separated using additional means of chemical leaching…. This method requires copious amounts of chemicals which result in excessive chemical waste (including radioactive sludge) which is both expensive and environmentally harmful.”

There have already been reports that Chinese ships are sailing into Japan’s “exclusive economic zone”—within which the mineral deposit is located—to either assess or steal the resources. If Japan can efficiently mine them, it has the potential to become a leading supplier of REEs—the deposit contains an estimated 780 years worth of yttrium, 620 years worth of europium, 420 years worth of terbium, and 730 years worth of dysprosium—severely cutting into China’s near-monopoly. EC_bug_web

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