Rainbow Rare Earths announced the progression of the Phalaborwa pilot plant process, with the rare earth oxide separation process now underway at the facilities of Rainbow's technical partner K-Technologies Inc. ("K-Tech") in Florida. This 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.

The process will produce all four of the critical rare earths used within permanent magnets, being neodymium and praseodymium (together "NdPr"), dysprosium ("Dy") and terbium ("Tb"). Bench scale testwork carried out by K-Tech is already showing positive rare earth oxide separation in line with expectations. The continuous run of the CIX /CIC pilot plant has also now commenced.

The first separated oxides to be delivered will be the NdPr, expected within the coming weeks, while the Dy and Tb will follow thereafter due to their presence in smaller volumes within the rare earth basket. The front-end pilot plant, which is situated at the Johannesburg facilities of the Council for Mineral Technology ("Mintek"), a global leader in mineral processing, extractive metallurgy, and related fields, has successfully completed the first two of three planned campaigns, from which ca. 5.75 kg of mixed rare earth carbonate have been shipped to K-Tech in five batches to date.

The front-end will start running on a continuous basis from the week commencing 15 January 2024. This integrated, whole-circuit campaign will produce increasing volumes ofmixed rare earth carbonate to ship to K-Tech over the course of First Quarter 2024. The pilot plant process is an iterative process that allows for continual optimisation in order to deliver the most efficient final flowsheet for commercial scale operations.

As part of this process, Rainbow has worked with its partner K-Tech to establish the optimal mixed rare earth product for the back-end CIX /CIC system. Having first successfully produced a mixed rare earth sulphate, it was decided to further beneficiate the product, removing certain unwanted elements, with the optimal end product for separation agreed as a cerium-depleted mixed rare earth carbonate, providing a higher-grade feedstock to the back-end separation circuit. The inclusion of this extra processing step into the front-end process does not add any significant capital or operating expenditure to the front-end flowsheet, but reduces the quantity of mixed rare earths to be processed in the CIX /CIC circuit by approximately 40%, with resultant capital and operating cost benefits.

In addition, the piloting process has delivered further optimisation results to date including: improvement in the impurity and rare earths leach temperature conditions from the 40°Cset out in the Preliminary Economic Assessment to 30°C, delivering a significant ca. 50% saving in energy requirements with resultant expected capex and opex savings; and the successful regeneration of two key reagents in the leach solution. 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.