Viridis Mining and Minerals Ltd (ASX:VMM) has described the maiden mixed rare earth carbonate (MREC) product from its Colossus project in Brazil as delivering ‘world class’ recoveries, including high grades of praseodymium, neodymium, dysprosium and terbium, together with overall MREO (magnetic rare earth oxide) recoveries (from ore to MREC) of 76%.
These results follow a work program run by the Australian Nuclear Science and Technology Organisation (ANSTO) for Viridis, which confirmed and optimised conditions for a flowsheet design which produces an MREC product from a clay bulk composite from the project’s Northern Concessions.
ANSTO’s test work yielded the highest known recoveries for all valuable MREO in a MREC product, with this being based on an economical ammonia-based flowsheet with leaching performed at pH4.5, 0.3M ammonia sulphate (AMSUL), at room temperature and with 30-minute residence time.
Praseodymium (Pr) recovery was 77%, while neodymium (Nd) was 76%, dysprosium (Dy) was 67%, and terbium (Tb) was 71%.
Colossus – based in Brazil’s Pocos De Caldas region – is an ionic adsorption clay project – and the test work from ANSTO also delivered the lowest impurity product for a project of this kind.
Viridis chief executive officer Rafael Moreno said this was the most significant result made by the company.
“As the industry grapples with depressed rare earth prices, the combination of superior basket value, exceptional recoveries, and its low-cost flowsheet sets Colossus apart from its rare earth peers,” he said.
“Having a high concentration of MREOs in your feed ore is one thing; another thing is to extract it efficiently and cheaply.
“Achieving best-in-class NdPr recoveries of 76% and DyTb of 68% with a flow sheet designed based on low cost, benign pH and readily available reagents, atmospheric
temperature, and pressure, is unheard of in the rare earth space, and highlights the disruptive nature of true ionic clays and why Colossus has the potential to re-set the cost curve.
“The extremely low levels of radionuclides and gangue elements in our MREC product bodes well for the ongoing offtake discussions being held, with low impurity levels paramount for the economic downstream processing of MREC into individual rare earth oxides.”
Viridis shares moved up on the news, and at 12:29 AEST, they were trading at 69.5 cents, a rise of 6.92% since the market opened.
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