Rio Tinto starts production of strategic metal tellurium at Kennecott mine

Rio Tinto has started producing tellurium at its Kennecott copper operation in Salt Lake County’s Bingham copper operation, becoming one of only two U.S. producers of the critical mineral used in advanced thin film photovoltaic solar panels.

Tellurium is listed as a critical mineral by the U.S. government due to its importance to the economy and energy security. It is one of 10 metals and products recovered from ore extracted at Kennecott, which produces nearly 15 percent of U.S. copper.

The tellurium will be refined in North America by 5N Plus, a leading global producer of specialty semiconductors and performance materials, under a commercial agreement between 5N Plus and Rio Tinto. The refined tellurium will primarily be supplied to First Solar, the only American company among the world’s 10 largest solar manufacturers, under an existing supply contract between 5N Plus and First Solar. A rio Tinto new release said 5N Plus will also use the tellurium to manufacture ultra-high-purity semiconductor materials at its facility in St. George, to serve the security and medical imaging markets.

Approximately 20 tons of tellurium will be produced per year through a new $2.9 million circuit built at the Kennecott refinery, the company said. Tellurium is recovered from byproduct streams generated during the copper refining process, reducing the amount of waste that needs to be treated and discarded as mine tailings.

“We are proud to deliver a new domestic supply of tellurium to support the manufacturing of solar panels and other critical equipment here in the United States,” said Clayton Walker, Rio Tinto Copper chief operating officer. “Approximately 90 percent of the world’s tellurium resource is contained in copper ore and no other metal has more critical mineral byproducts than copper. The Kennecott team is constantly looking for ways to extract new critical minerals to meet emerging demand for the clean energy transition.”

“As a leading global supplier of specialty semiconductor compounds for applications in renewable energy, security and medical imaging, 5N Plus is proud of this partnership with Rio Tinto, and to further leverage its expertise in the transformation of mining and metallurgical byproducts into high-purity value-added critical minerals such as tellurium, here in North America,” said Gervais Jacques, 5N Plus president and CEO.

Mike Koralewski, First Solar chief manufacturing operations officer, said, “Rio Tinto’s decision to invest in tellurium is a win for responsibly-produced, American solar. We’re thrilled that tellurium from Kennecott will play a role in powering our country’s transition to a sustainable energy future.”

“Utah continues to play a key role in domestic production of critical minerals,” said Gov. Spencer Cox. “With operations in our state like Rio Tinto Kennecott, we are able to demonstrate to the world how to responsibly make use of our natural resources to move toward a sustainable future.”

Rio Tinto also said it is partnering with the U.S. Department of Energy’s Critical Materials Institute (CMI) to discover further ways to economically recover critical minerals such as tellurium and lithium. The company is also investing in new facilities to extract battery-grade lithium from waste rock at its Boron, California, mine site and high-quality scandium oxide from waste streams at its metallurgical complex in Sorel-Tracy, Quebec, Canada.