Rainbow Rare Earths announced 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 extractionwhich 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 acerium-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: Stage 1: Impurity Removal via CIX; Stage 2: Group separation via CIC (in two steps); and 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. Stage3 purifies the separated target groups into the individual desired separated rare earth oxides. A summary of the progress made with the back-end flowsheet is as follows: successful impurity removal in the initial ion-exchange step providing suitable feed solution for group separation; successful separation of the uneconomic lanthanum and cerium group; successful group separation in the first step of the chromatography stage, delivering a NdPr group, grading ca.

68%, as feed for purification in the subsequent individual chromatography separation steps; considerable upgrading of the concentration of the Dy and Tb from a combined feed grade of 0.9% to 14.6%, which requires separation from the SEG group; and good separation of the samarium, europium and gadolinium ("SEG") group at a grade of ca. 63%, which as a group provides the strong potential for an additional valuable product line as a combined Sm-Eu-Gd oxide concentrate. The current focus of the pilot plant test work at K-Tech is to optimise the second stage of the chromatography process to produce a 99.5% NdPr product.

This will be followed by CIC testing to separate and purify the separate Dy and Tb 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. The four rare earths that will be produced at Phalaborwa - NdPr, Dy and Tb - are all designated as critical minerals further to their important role in the transition to the green economy. As vital components of permanent magnets, these rare earth elements are used within electric vehicles and wind turbines, as well as many other advanced technologies including those required for strategic defence purposes, such as guided missiles, drones, electronic displays, sonar and jet fighter engines.

The SEG rare earths are samarium (used in magnets), europium (used in optical displays) and gadolinium (used in medical and nuclear applications).