MRD’s 94.9% gallium recovery puts bauxite back in the critical minerals spotlight

Mount Ridley Mines has reported 94.9 per cent gallium recovery from a third-party bauxite sample using its patent-pending Selectro process, alongside recoveries of 92 per cent aluminium and 97 per cent iron in a single low-temperature leach. The test also produced a silica-rich residue instead of conventional red mud, highlighting the technology’s potential to recover multiple metals from bauxite through one processing route.

The sample was provided by Australian Silica Quartz Group from its Darling Range bauxite project in Western Australia. It comprised material collected from 16 vacuum drill samples across four holes at the Athena and Ceres prospects.

Containing 80 parts per million of gallium, the sample yielded an extraction rate of 94.9 per cent into solution. Mount Ridley said this compares with approximately 70 per cent typically extracted into liquor through the Bayer process.

Under conventional alumina refining, gallium dissolves into the process liquor but requires a dedicated recovery circuit to be separated, adding complexity and cost to its potential production. Selectro’s reported results could offer an alternative pathway for recovering the critical mineral from bauxite.

Mount Ridley managing director and CEO Allister Caird said the results strengthened the company’s focus on critical minerals and the potential for technology to support new gallium supply.

“Our gallium result completes the bauxite picture and brings us full circle back to our focus on critical minerals,” Caird stated. “Bauxite is the world’s main source of gallium, but recovering it through conventional refining requires dedicated circuits that are costly to build".

“We have long held the view that technology is the most effective way to deliver a new source of gallium supply. We believe Selectro™ shows strong potential here, a position further strengthened by the clean, silica-rich residue left in place of red mud and strong recoveries of aluminium at 92 per cent and iron at 97 per cent," he later added. 

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Silica-rich residue offers potential processing advantage

The residue produced during the test is another notable feature of the process. Conventional Bayer refining generates red mud with gallium that is not extracted into the caustic liquor, remaining in the bauxite residue.

Mount Ridley reported that Selectro avoided generating conventional red mud in the trial, retaining more than 90 per cent of the original silica in a silica-rich residue. This could offer a different residue-management pathway, although further work is needed to establish the environmental and economic performance of the process at a commercial scale.

The test was conducted at temperatures below 100°C. Selectro has also been designed as a closed-loop leaching system with reagent recycling, features that could provide operational and environmental benefits if demonstrated at a larger scale.

The company is continuing to investigate reagent formulations and metal recoveries across different feedstocks, with the aim of extracting aluminium, iron and critical minerals through a single processing route.

Gallium supply security adds to interest

The results come amid efforts to diversify supply chains for gallium, which is used in advanced semiconductor technologies, including gallium arsenide and gallium nitride devices for defence radar, electronic warfare, communications and power electronics.

China accounts for approximately 99 per cent of global primary gallium production, according to the supplied report, while the United States has no domestic primary production and relies entirely on imports. Demand is also being driven by applications including artificial intelligence data centres and electric vehicles.

Industry analyst Yole Group forecasts that the gallium nitride power-device market will grow at a compound annual growth rate of 35 per cent to reach USD 3.5 billion by 2031.

China has suspended its ban on gallium exports to the United States until November 27, 2026, but licensing requirements and restrictions on supplies to US military users remain in place, according to the source. Uncertainty over future restrictions has kept alternative supply chains in focus.

Other efforts to establish gallium production include Alcoa’s planned gallium facility at its Wagerup alumina refinery in Western Australia’s Darling Range.

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Selectro development moves towards further testing

The bauxite trial builds on earlier Selectro testwork at Mount Ridley’s Grass Patch critical minerals project, located 25 kilometres north of Esperance in Western Australia. Previous tests on Grass Patch material achieved scandium recoveries of 91.8 per cent and average heavy rare earth recoveries of approximately 84 per cent, using around half the reagent dose applied in earlier tests.

Mount Ridley said the latest bauxite results demonstrate the potential adaptability of Selectro’s chemistry across different mineral feedstocks. The company attributed the gallium result in part to reagent optimisation for bauxite.

It has also lodged a separate provisional patent application covering industrial metals, opening up potential commercialisation pathways beyond its critical minerals work.

“This result builds on the strong recoveries achieved from our own critical minerals basket at Grass Patch and has prompted us to turn our immediate attention to separation and purification pathways for both bauxite and Grass Patch feeds,” Caird said.

Mount Ridley is awaiting results from a second bauxite test intended to further optimise the process. Additional testing on third-party feedstocks is planned as the company advances the design and construction of a Selectro demonstration plant.

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