Axel REE (ASX:AXL) reports high magnetic rare earth oxide recoveries of more than 96% from acid leach testwork at its Caladão project in Brazil’s Minas Gerais state.
The Australian Nuclear Science and Technology Organisation (ANSTO) conducted hydrochloric acid leach tests on selected composites from two diamond holes approximately 2km apart in Area A of the project.
The company says hydrochloric acid tests delivered stronger overall extraction compared to sulphuric acid, representing a substantial improvement versus earlier acid leach outcomes.
Axel REE’s development strategy remains focused on prioritising ionic adsorption clay wellfields for modular ISR using magnesium sulphate (MgSO₄), targeting a pathway designed to be scalable and repeatable across multiple wellfields.
In parallel, the ANSTO acid leach results provide clear longer-term processing optionality – a potential pathway to extract magnetic rare earths from non-ionic clay areas (and/or portions of the profile less responsive to mild salt leaching), supporting a broader concept of maximising MREO recovery over the life of the project.
Given the company’s current focus on ISR pathway definition and scale-up, no further acid leach testing is planned at this stage, however the acid leach route remains a viable option to revisit as Caladão progresses.
Non-executive Chairman Paul Dickson says the results reinforce Caladão’s unique advantage.
“ANSTO’s results reinforce Caladão’s unique advantage: the ability to prioritise our strategy to progress low-cost, in-situ recovery (ISR) on the ionic clay-hosted mineralisation using MgSO₄, while also demonstrating that magnetic rare earths and gallium can be extracted at very high recoveries under acid leach conditions from selected non-ionic composites,” Dickson says.
The testwork supports a two-pathway development concept at Caladão, comprising near-term modular in-situ recovery targeting ionic adsorption clay zones using magnesium sulphate in priority wellfields, and longer-term acid leach processing to extract magnetic rare earth oxides from non-ionic portions.
Gallium recovery increased to approximately 30% in the latest tests, building on previous testwork that achieved up to 50% gallium recovery using oxalic acid.
Caladão currently hosts an inferred mineral resource estimate of 233Mt at 2,133ppm total rare earth oxides in Area A, with a further 339Mt at 1,072ppm total rare earth oxides across three deposits in Area B.
The project also contains an inferred gallium resource of 439Mt at 37.8ppm gallium across Areas A and B.
No further acid leach testing is planned at this stage as the company focuses on advancing its ISR pathway.
This content was created with AI assistance and human editing.
Images: Axel REE
