Axel REE Extracts High Gallium and Scandium Values from Testing of Tiger Creek Samples

Axel REE (ASX: AXL) has reported 95% gallium and 74% scandium extractions achieved through metallurgical testing of ore samples from its Caladão rare earths project in Brazil.

The high values were returned from independent test work on a 63 parts per million gallium composite from the weathered profile of the Tiger Creek target.

The metals were extracted using acid leach processes which are being evaluated as a separate metallurgical pathway from Axel’s magnesium sulphate in-situ recovery development program for ionic clay hosted rare earths and exploratory field trials.

Tiger Creek hosts an Inferred mineral resource of 85 million tonnes at 40ppm gallium and 1,050ppm total rare earth oxides, within the broader Caladão project’s 439Mt @ 38ppm.

Batch Leach Tests

CORE Resources performed 18 batch leach tests using sulphuric acid and oxalic acid as lixiviants at 10% weight per weight solids for 48 hours, target temperatures of 50° Celsius, 70°C, and 90°C, and target acid concentrations of 25 grams per litre, 50g/L, and 100g/L.

Sulphuric acid extracted 90% gallium and 70% scandium, while oxalic acid extracted up to 95% gallium and 74% scandium.

The sulphuric acid result provides an alternative conventional acid leach chemistry for further optimisation, with Axel classifying 90% gallium extraction in a conventional sulphate system as a significant result in its own right.

CORE found that raising temperatures generally did more for gallium and scandium extraction than raising acid concentration (particularly with sulphuric acid), and the next phase of testing is expected to improve extraction values at lower acid concentrations.

Different Acid Systems

Axel managing director Patience Mpofu said the results represented a real step forward for the Caladão metallurgical program.

“We achieved above 90% gallium extraction using two entirely different acid systems, with scandium extraction of up to 74%, so we are not locked into one chemistry at this stage,” she said.

“Global gallium supply is overwhelmingly produced as a by-product principally from the processing of bauxite for alumina, making the identification of alternative gallium recovery pathways strategically important.”

“Showing that gallium can be leached from Caladão material at these levels gives us something solid to build on.

Ms Mpofu said the next phase of testing would focus on “reagent consumption, selectivity against aluminium and iron, and getting the gallium and scandium back out of solution.”