Rio Tinto to start producing tellurium in Utah

UK-Australian mining firm Rio Tinto will build a plant to recover critical mineral tellurium at its Kennecott copper mine in the US state of Utah, strengthening the supply chain for advanced thin-film solar panels.

Rio Tinto is investing $2.9mn in the 20 t/yr plant, which will recover tellurium as a by-product of copper refining at the Kennecott mine, near Salt Lake City. Production is expected to start in the fourth quarter of this year. The largest tellurium consumer in North America is Arizona-based First Solar, which manufactures cadmium telluride thin-film solar power modules.

"We welcome the decision to construct the new plant in Utah. This facility creates a new domestic source of a critical mineral that is essential in the fight against climate change. We are in early stage talks with Rio Tinto but cannot release any further details yet," First Solar said in response to today's announcement.

Tellurium is a semiconductor used in a variety of applications but the largest is cadmium-telluride thin-film solar, which accounts for as much as 40pc of global demand. Next is advanced thermo-electric devices for heating and cooling, which use around 30pc. It is also used as an additive in steel and in the production of rubber. And it has applications in medical devices and CT scanning.

This latest project is a continuation of Rio Tinto's push to recover critical minerals from existing production sources. The company earlier this year announced the start of construction of a scandium-oxide plant at its Sorel Tracy metallurgical plant near Montreal, in Canada's Quebec province, which would make it the largest single scandium producer in the world.

By Caroline Messecar