18 May 2022
Rio Tinto starts tellurium production at Kennecott
Rio Tinto has started producing tellurium at its Kennecott copper operation in Utah, becoming one of only two US producers of the mineral. Tellurium is listed as a critical mineral by the US Government due to its importance to the economy and energy security.
The tellurium will be refined in North America by specialty semiconductors and performance materials producer 5N Plus Inc of Montreal, Québec, Canada under a commercial agreement between 5N Plus and Rio Tinto. The refined tellurium will primarily be supplied to cadmium telluride (CdTe) thin‐film photovoltaic (PV) module maker First Solar Inc of Tempe, AZ, USA (the only American company among the world’s ten largest solar manufacturers) under an existing supply contract between 5N Plus and First Solar. 5N Plus will also use the tellurium to manufacture ultra-high purity semiconductor materials at its facility in St. George, Utah, to serve the security and medical imaging markets.
About 20 tons of tellurium will be produced annually through a new $2.9m circuit built at the Kennecott refinery. The material is recovered from by-product 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,” says Rio Tinto Copper chief operating officer Clayton Walker. “About 90% of the world’s tellurium resource is contained in copper ore and no other metal has more critical mineral by-products than copper. The Kennecott team is constantly looking for ways to extract new critical minerals to meet emerging demand for the clean energy transition,” he adds.
Tellurium is one of ten metals and products recovered from ore extracted at Kennecott, which produces nearly 15% of US copper.
Rio Tinto is partnering with the US Department of Energy’s Critical Materials Institute (CMI) to discover further ways to economically recover critical minerals such as tellurium and lithium. The firm 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.
First Solar is expanding its US manufacturing capacity by 3.3GW annually, by building its third American manufacturing facility in Lake Township, Ohio. When fully operational, the new facility will scale the firm’s Northwest Ohio footprint to a total annual capacity of 6GW (making it the largest fully vertically integrated solar manufacturing complex outside of China, it is believed).