5 February 2024

Rainbow Rare Earths Limited

(“Rainbow” or “the Company”)

LSE: RBW

Rainbow Rare Earths Update on Rare Earth Oxide Separation Progress

News Release

Rainbow Rare Earths (LSE: RBW) is pleased to announce an update on progress with regards to the ongoing rare earth oxide separation work underway at the back-end pilot plant, which is located at the facilities of Rainbow’s technical partner K-Technologies, Inc. (“K-Tech”) in Florida.

The back-end plant process utilises continuous ion exchange (“CIX”) and continuous ion chromatography (“CIC”) to produce separated rare earth oxides. The innovative application of this established technology has been pioneered by K-Tech in the rare earth space and replaces traditional solvent extraction which uses toxic and flammable solvents and diluents and requires more than 100 separate stages.

As previously announced, the optimal feed for the back-end process has been determined by Rainbow and K-Tech as a cerium-depleted mixed rare earth carbonate, which provides a higher-grade feedstock to the back-end separation circuit.

The initial separation at the back-end pilot plant has been achieved using the mixed rare earth carbonate successfully produced from phosphogypsum from the Phalaborwa project.  This material, which includes cerium, was previously shipped to K-Tech from the front-end pilot plant located at the Johannesburg facilities of the Council for Mineral Technology (“Mintek”), a global leader in mineral processing, extractive metallurgy, and related fields. Cerium depletion test work is ongoing at both K-Tech and Mintek and the cerium-depleted carbonate, once available, is expected to produce better results in the CIX / CIC separation circuits.

The back-end plant process comprises three main stages, as depicted in the simplified CIX / CIC block flow diagram to follow, being:

1.    Stage 1: Impurity Removal via CIX;

2.    Stage 2: Group separation via CIC (in two steps); and

3.    Stage 3: Individual separation via CIC (in three steps).

Stage 1 removes remaining impurities from the mixed rare earths feed. Stage 2 then uses CIC to separate the targeted rare earth elements (NdPr, Dy, Tb) into groups from the uneconomic rare earth elements. Stage 3 purifies the separated target groups into the individual desired separated rare earth oxides.

In addition, the production of a separated and purified SEG oxide product will be evaluated and followed up. Initial indications are that Phalaborwa could produce ca. 500 tonnes per annum of a saleable SEG product which, in addition to the previously announced off-take for the residual gypsum, provides the potential for an additional revenue stream for the project with minimal capital and operating costs.

George Bennett, CEO of Rainbow, commented: 

“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.

 

“It is also notable that we have achieved positive separation in the chromatography circuit of the SEG group of rare earth oxides, which could add another very saleable product and revenue stream to Rainbow at minimal cost.”