Low impurities at Ema project boosts BCM's path to efficient REE production

ANSTO testing shows BCM’s Ema project leach solution contains very low impurities
Results achieved using industry standard leaching methods, indicating low CapEx potential
BCM will soon start impurity removal and MREC production as part of its scoping study

Special Report: Testing by ANSTO – Australia’s Nuclear Science and Technology Organisation – has proven that it is possible to produce a valuable mixed rare earth carbonate (MREC) with very low impurities using material from Brazilian Critical Minerals’ Ema REE project in Brazil.

Final optimised slurry leach assays completed on the Ema project master composite that comprised 62 samples collected from 12 holes to mimic a tank leaching project setup returned very low impurities such as 0.2mg/l uranium, 0.02mg/l thorium, 73mg/l aluminium and <1mg/l iron.

This is an excellent result as impurities can affect REE precipitation efficiencies and final MREC product specifications

What’s every bit as exciting for Brazilian Critical Minerals (ASX:BCM) is that the results were achieved using standard weak 0.3 M ammonium sulphate leaching solution, pH 4.5, at ambient temperature and short leach times of just 30 minutes duration with a solid density of 40wt%.

This means that the company will not have to take special steps in order to produce a saleable MREC with very low impurities.

BCM is also confident that the low uranium and thorium values can be removed through simple pH adjustment during the next stage of impurity removal leading to a final MREC product ready for specification testing to advance discussions regarding global commercial offtake.

“These results confirm BCM finds itself in [an] enviable position, after having completed a suite of tests under differing conditions with different reagents, in that the Ema mineralisation has a fairly large window of conditions where rare earth recoveries and impurity concentrations are similar,” said managing director Andrew Reid.

“The unique characteristics of Ema means that BCM can now evaluate different processing strategies such as heap leaching and in-situ leaching on its journey towards a low CapEx practical project solution that is tailored towards the current rare earth market and does not require pricing levels which are 2 or 3 times current spot levels as most projects now need.

“Test work programs to prove these alternative process strategies have commenced.

“The current drilling program is progressing smoothly and we expect to kick start the scoping study very shortly as we bed down the final criteria, which will be used as the basis for the assessment.”

Ema project

The Ema ionic adsorption clay-hosted project in Brazil shares almost identical characteristics with other ionic deposits developed over felsic volcanic rocks in southwest China, the world’s largest known ionic clay region.

IAC deposits that typically have much higher percentages of magnet rare earth oxides (MREOs) are easier to explore due to mineralisation being near-surface, and therefore cheaper to mine and process.

Earlier metallurgical test work has already proved that the clays at Ema are right up there with the best performers of its kind around the world, achieving MREO recoveries of up to 83% – and averaging ~68% – using standard weak ammonium sulphate leaching solution with a pH of four at ambient temperatures over a low leach time of just 30 minutes.

The project has an existing resource of 1.02Bt grading 793ppm TREO.

Upcoming activity

BCM has now started the final process steps of impurity followed by precipitation of REEs from solution to make the MREC at ANSTO.

A 12-week exploration program to upgrade the high-grade portion of the project’s inferred resource is currently underway with first results expected in August.

The scoping study and restart of environmental baseline studies is also in final negotiation.

An updated MRE will also be calculated during Q4 2024.

This article was developed in collaboration with Brazilian Critical Minerals, a Stockhead advertiser at the time of publishing.

This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions