Rio Tinto considers move into large-scale scandium production

The potential timing, scale and investment in the industrial production of the rare earth metal – which is deemed a critical mineral in the United States, Canada, Australia and the European Union – are all being assessed, Rio Tinto said.

Scandium is used in a range of industries, including light-weighting in aerospace and transportation, 3D printing and fuel cells.

Rio Tinto has already developed a new process to extract high-purity scandium oxide from by-products generated in the production of titanium dioxide at its RTFT metallurgical operation in Quebec, Canada.

Its RTFT Research & Development Centre in Sorel-Tracy has been producing scandium oxide since the second half of 2019 and the process is now being used at a larger scale at a pilot facility.

Rio Tinto chief executive J-S Jacques said the advances in scandium are a good example of how the company is looking at its operations to determine how to extract value from by-product streams, which in turn helps the company to reduce waste.

“Scandium, produced at an economic scale, is a critical mineral that has the potential to provide unique solutions to materials science challenges and drive progress in manufacturing,” Jacques said.

“This exciting breakthrough in processing technology leverages our existing mining operation to provide what can be a scalable, high-quality and low-cost source of scandium oxide,” he added.

Titanium industry sources estimate the global market is evenly split at 80,000 tonnes for aerospace titanium scrap and 80,000 tonnes for mixed ferro-titanium scrap, which is used in steel production.

Fastmarkets’ price assessment for ferro-titanium 70% Ti, max 4.5% Al, ddp Europe, stood at $4.5-5 per kg on April 8, consolidating gains made in the first week of April.

Rio Tinto is also trialling the production of small quantities of an aluminium-scandium master alloy by combining the scandium oxide produced by RTFT with output from its aluminium business, also based in Quebec.

Small additions of scandium into aluminium alloys increases strength, heat and corrosion resistance, along with substantially improving welding properties.

Scandium fundamentals
Previously, the high costs associated with scandium have deterred its use. But both of Rio Tinto’s scandium oxide and master alloy streams have low production costs and require minimal capital investment because there are no direct mining costs, they use existing metallurgical plants and have no impact on the main process flow.

Security of supply issues and a high cost of production have limited the growth of demand for scandium for many years, with the US Geological Survey estimating global supply and consumption to be about 15-20 tonnes per year.

Scandium is present in most rare-earth deposits and in bauxite residues – commonly known as red mud. 

To date, however, it has only been extracted from ores in a few mines worldwide – predominantly in China, Japan, Kazakhstan, the Philippines and Russia.

Major aircraft producers have been assessing the adoption of aluminium-scandium alloys to reduce aircraft weight by 15-20%.

APWorks in Germany – in co-operation with the Airbus Group’s research & development division – has developed Scalmalloy, a high-performance scandium-aluminium magnesium alloy designed for the additive manufacturing of high-strength aerospace structures.