Tag Archives: selenium

Rio Tinto Kennecott to recover tellurium from copper smelting

Rio Tinto is to construct a new plant that will recover tellurium, a critical mineral used in solar panels, from copper refining at its Kennecott mine near Salt Lake City, Utah.

The company is investing $2.9 million to set up the plant, which will recover tellurium as a by-product of copper smelting, extracting a valuable mineral from waste streams. The plant will have a capacity to produce around 20 t/y of tellurium, the miner said.

Rio expects to begin production of tellurium in the December quarter of 2021, creating a new North American supply chain for the critical mineral.

Tellurium is an essential component of cadmium telluride, a semiconductor used to manufacture thin film photovoltaic solar panels. Thin films made of this compound can efficiently convert sunlight into electricity, according to the miner. Tellurium can also be used as an additive to steel and copper to improve machinability, making these metals easier to cut. It can also be added to lead to increase resistance to sulphuric acid, vibration and fatigue.

Rio Tinto Kennecott Managing Director, Gaby Poirier, said: “The minerals and metals we produce are essential to accelerate the transition to renewable energy. Adding tellurium to our product portfolio provides customers in North America with a secure and reliable source of tellurium produced at the highest environmental and labour standards with renewable energy. Rio Tinto is committed to using innovation to reduce waste in our production process and extract as much value as possible from the material that we mine and process.”

Utah Governor, Spencer Cox, said: “With abundant natural resources, Utah is ideally positioned to help supply the critical minerals essential to maintain American manufacturing competitiveness. Rio Tinto’s smelter at Kennecott is one of only two that is capable of producing copper and other critical minerals. The new tellurium plant is another valuable contribution to critical mineral independence and energy security in the US”

Along with producing almost 20% of US copper, Kennecott’s smelting process also recovers gold, silver, lead carbonate, platinum, palladium and selenium, while molybdenum is recovered from the Copperton concentrator. In total, nine products are currently recovered from the ore extracted at Kennecott.

Rio Tinto is a partner with the US Department of Energy’s Critical Materials Institute (CMI) and works closely with CMI experts to discover further ways to economically recover critical mineral by-products such as rhenium, 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.

BQE Water hits Selen-IX milestone at Kemess gold project

BQE Water says it has successfully completed the commissioning and performance test of the first industrial scale plant using its patented Selen-IX™ process for selenium management.

The installation at the Kemess property in northern British Columbia, Canada, owned by Centerra Gold has, since late August 2020, operated continuously. It has treated 65 litres/s (5,600 cu.m/d) of mine-influenced water to produce effluent containing selenium concentrations of less than two parts per billion, BQE Water said.

Fully staffed and operated by BQE Water with support from Centerra Gold mechanical and electrical maintenance personnel, the plant is expected to operate until the end of October and then shut down for the winter season. Plant operations are expected to restart in the Spring of 2021, BQE Water says.

Selen-IX was developed by BQE Water specifically to address the difficult to remove ‘selenate’ form of selenium from mine-influenced waters employing a physico-chemical, instead of biological, method of treatment.

As the Kemess mine plant enters the operations phase, Selen-IX becomes the first commercially available non-biological treatment process to be applied on a large industrial scale capable of removing selenate to levels below two parts per billion, BQE Water said. This is achieved without the risk of inadvertent organo-selenium production that is associated with biological systems. Additionally, the solid residue produced by Selen-IX is stable and is suitable for blending with tailings.

“This plant provides confirmation that a proven non-biological treatment approach for selenate is now available, something that has been lacking since selenium regulations were first introduced,” the company said.

Ron Hampton, Project Director for the Kemess project at Centerra Gold, said: “We are pleased that the water treatment plant met the conditions of the performance test, which is a major milestone for our project. The ability to effectively control selenium is key to the future operation of the Kemess underground project.”

David Kratochvil, President & CEO of BQE Water, added: “Centerra Gold’s exemplary commitment to a clean environment enabled us to first pilot and then implement Selen-IX on the basis of delivering a selenium management solution with superior outcomes compared to treatment systems used at other mines. I am extremely proud that we delivered on that promise.”

Centerra Gold is looking to re-establish the former operating Kemess site into an underground mine and processing facility, able to operate over a 12-year mine life, according to a 2016 feasibility study.