Rhodium is a precious metal that is highly reflective and strongly resistant to corrosion. It is considered the rarest and most valuable precious metal in the world, far more so than gold or platinum. Rhodium has a variety of uses, including:
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Catalytic converters: The primary use of rhodium is in catalytic converters for cars, where it reduces nitrogen oxides in exhaust gases. In fact, almost 90% of rhodium demand in 2019 was from the auto-catalyst sector.
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Chemical industry: Rhodium is used as a catalyst in the chemical industry for making nitric acid, acetic acid, and hydrogenation reactions. Catalysts containing rhodium help make raw materials used in the production of fertilizers and explosives.
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Optics: Rhodium is used to coat optic fibers and optical mirrors, and for crucibles, thermocouple elements, and headlight reflectors.
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Jewelry: Rhodiums high shine and resistance to scratching and tarnishing make it useful as a plating for jewelry. It is electroplated on white gold and platinum to give it a reflective white surface at the time of sale, after which the thin layer wears away with use.
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Other uses: Rhodium is used in the glass industry for the production of fiberglass and flat-panel glass, and in the production of liquid crystal displays (LCDs) . It is also used as an anti-wear coating and catalyst in high-tech instruments, such as telephone repeaters, headlight mirrors, and pen tips. Rhodium detectors are used in nuclear reactors to measure the neutron flux level.
Rhodium is obtained commercially as a by-product of copper and nickel refining, and world production is about 30 tonnes per year.
