Rainbow Rare Earths Ltd (LSE:RBW, OTC:RBWRF) said rare earth oxide separation has been achieved at its pilot plant, putting it “on track” to deliver individual separated rare earth oxides.
Four rare earths are produced at its Phalaborwa project in South Africa – neodymium and praseodymium (NdPr), dysprosium (Dy) and terbium (Tb) – which are all seen as critical minerals for the energy transition.
The company reported advancements in oxide separation at its ‘back-end’ pilot plant in Florida, USA, where partner K-Tech has successfully produced separated rare earth oxides from mixed rare earth carbonate derived from the Phalaborwa project.
K-Tech, which uses continuous ion exchange (CIX) and chromatography techniques (CIC) as a safer alternative to traditional solvent extraction, has successfully completed the first step of separation, delivering a NdPr group, grading roughly 68%, as feed for purification in the subsequent individual chromatography separation steps.
Rainbow said the current focus at K-Tech is to optimise the second stage of the chromatography process to produce a 99.5% NdPr product.
Rainbow chief executive George Bennett said: "I am very pleased with the continued progress to date validating our front-end process flow sheet and the K-Tech CIX/CIC process flow sheet for the back-end.
“The back-end process is on track to deliver separated high purity rare earth oxides of NdPr, Dy and Tb, the four most economically important rare earth elements due to their crucial role in the green energy transition.”
He also highlighted the achievement of positive separation in the chromatography circuit of the SEG group of rare earth oxides, samarium, europium and gadolinium, “another very saleable product and revenue stream” for Rainbow with minimal capital and operating costs.
K-Tech is to complete further CIC testing to separate and purify the separate Dy and Tb oxides, with the production of a separated and purified SEG oxide product to be evaluated.
Phalaborwa could produce around 500 tonnes per annum of a saleable SEG product, the company estimated, which would be in addition to the previously announced off-take for the residual gypsum.