Rio Tinto researchers have developed a new process to extract high purity scandium oxide, a critical mineral, from by-products generated in the production of titanium dioxide at the Rio Tinto Fer et Titane (RTFT) metallurgical operation in Sorel-Tracy, Quebec.
The company states: “We are now producing high quality scandium oxide that meets market specifications as part of an ongoing pilot, as well as trialling the production of a scandium aluminium master alloy. This breakthrough has the potential to enhance the scandium oxide market by delivering a secure supply source from this established operation, creating value from what was previously waste.”
The RTFT metallurgical operation in Sorel-Tracy processes ilmenite ore to produce titanium dioxide feedstocks. Researchers in the RTFT Research & Development Centre have developed a new process to extract high purity scandium oxide from by-products generated in the production of titanium dioxide feedstocks. Since the second half of 2019, a lab has been producing high quality scandium oxide that meets market specifications and the process is now being used at a larger scale in a pilot plant.
Rio Tinto is also trialling the production of small quantities of high-performance aluminium-scandium master alloy using the scandium oxide produced by RTFT with its world class aluminium business, also based in Quebec. This disruptive process presents low production costs and requires minimal capital investment:
- No direct mining costs
- Recovery of scandium oxide directly from by-products from the existing metallurgical plant
- Operating independently from existing assets with no impact on the main process flow
Rio Tinto says it is seeing strong interest in the market and is now assessing the potential to progress to industrial scale scandium oxide production. The potential timing, scale and investment in industrial production are being considered.
Rio Tinto Chief Executive J-S Jacques stated: “This breakthrough on scandium is a great example of how we are looking at our operations across the world with fresh eyes to see how we can extract value from by-product streams. Finding a way to extract a new product not only delivers more value from our orebodies, it helps to reduce waste. It’s a key part of operating in a more responsible way and providing the essential materials our world needs for a sustainable future. Scandium, produced at economic scale, is a critical mineral that has the potential to provide unique solutions to materials science challenges and drive progress in manufacturing. 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 to markets and manufacturers.”
Scandium is a silvery-white, rare earth metallic element. The United States, Canada, Australia and the European Union have all listed it as a critical mineral in recent years. Scandium oxide is used to improve the performance of solid oxide fuel cells, which are used as a power source for buildings, as well as in niche products such as lasers and lighting for stadiums or studios. Scandium is also used to produce high-performance aluminum alloys. Small additions of scandium into aluminum alloys increase strength, heat and corrosion resistance, and welding properties substantially.
Since the 1980s, scandium-aluminium alloys have been used for structural purposes to provide weight, manoeuverability and range advantages to military aircraft. Today, aluminium-scandium-magnesium alloy powder is even used in 3D printing. Numerous applications have also been developed for sports equipment such as baseball bats, lacrosse sticks and bicycle frames. Kona Bikes estimates that scandium enables them to “shave weight from their aluminum frames by 10-to-15%.”
Security of supply issues and a high cost of production have limited the growth of demand for scandium for many years, with the current market estimated to represent 12-14 t per annum, according to the Scandium Aluminium Europe (SCALE) project.
Scandium is present in most rare-earth deposits and in bauxite residues, commonly known as red mud. However, to date it has been extracted from ores in only a few mines worldwide, mostly concentrated in Asia (China, Japan, Kazakhstan, the Philippines) and Russia. In January 2020, Canada and the United States finalised a Joint Action Plan on Critical Minerals Collaboration in order to secure supply chains for critical minerals – such as scandium – that are “needed for important manufacturing sectors, including communication technology, aerospace and defence, and clean technology.”
