Alcoa Looks At Critical Mineral Potential Of Residue

US aluminium producer Alcoa has partnered with Brisbane-based Alumtek Minerals, the developer of a process to extract critical minerals including gallium, vanadium, hafnium and rare earths from mining waste.

Alcoa will work with Alumtek and Western Australian government research hub ChemCentre to try to advance the processing technology from proof of concept to producing commercial trial quantities of several critical minerals from bauxite tailings. The project is expected to take 15 months and has received a A$1mn ($730,000) grant from the Australian government to cover half of the cost.

Bauxite residue, or red mud, is material that is discarded after the processing of rock containing aluminium-bearing minerals (bauxite ore) into alumina (aluminium oxide). Alumina is the intermediate stage before aluminium metal production.

“Depending on the bauxite source, for every tonne of alumina you refine you get 1-2t of red mud waste,” Alumtek Minerals director Craig Wilson said. “Our process has the potential to turn an environmental and financial liability into a source of critical minerals needed for aerospace, defence, electronics, high-speed telecom networks and batteries.”

The concept of extracting critical minerals from red mud waste is not new and there are several projects around the world looking at processes. They all face fierce price competition from incumbent suppliers, mainly China. For example, almost all the world’s primary supply of gallium — used in electronics, high-performance rare earth magnets, LEDs and communications — is produced as a by-product of China’s aluminium industry.

Sustainability

In addition to extracting saleable mineral by-products, Alumtek is designing its process to neutralise the leftover material for use as road base, cement additive and in water treatment.

Australia is the world’s largest bauxite miner and the second-largest producer of alumina. The volume of bauxite residue is large and growing, and expensive for alumina producers to maintain. “Developing circular economy solutions for bauxite residue is a key sustainability objective of our project partners,” Wilson said.

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