Mount Ridley Mines (ASX:MRD) reports its Selectro process achieved 92% aluminium recovery and 97% iron recovery from composite bauxite samples in the technology’s first third-party bauxite test.
The samples were supplied by Australian Silica Quartz Group (ASX:ASQ) from its Darling Range Project in Western Australia. ALS Australia conducted the test on Mount Ridley’s behalf.
The process produced a small, pH-neutral, silica-rich residue rather than the red mud generated by conventional Bayer refining. More than 90% of the silica remained in the residue, with leaching conducted below 100°C compared with the 145–250°C used in Bayer digestion.
The test marks Selectro’s first application to feedstock outside the company’s Grass Patch Complex and its first on bauxite. The composite was prepared from 16 vacuum drill samples taken from four drill holes across ASQ’s Athena and Ceres prospects.
Managing Director Allister Caird says the result demonstrates ‘Selectro’s potential’ beyond Mount Ridley’s existing mineral resources.
“Bauxite is a very different material to our Grass Patch feed, and achieving these recoveries on our first test demonstrates the potential for Selectro to be applied well beyond MRD’s existing mineral resources,” Caird states.
The dried leach residue was about 25% of the original feed mass and consists predominantly of silica. Mount Ridley has not independently verified ASQ’s drilling, sampling, or survey data.
The Bayer process generates an estimated 150–200 million tonnes (Mt) of bauxite residue annually, with global stockpiles estimated at about 4 billion tonnes. Global primary aluminium production reached about 73.8Mt in 2025.
Mount Ridley plans to optimise the Selectro chemistry for bauxite feed and demonstrate separation and purification steps to recover aluminium and iron products from the leach solution.
The company is also designing and constructing a Selectro demonstration plant to validate the flowsheet at scale.
Gallium results from the bauxite test are expected within a week. Selectro has previously demonstrated gallium recovery from Grass Patch feed.
Mount Ridley Mines is an Australian critical minerals explorer advancing rare earth and scandium projects across Western Australia.
Write to JC Villarba at Mining.com.au
Images: Mount Ridley Mines
