Successful Development of Extraction Flowsheet

28 June 2022

Rainbow Rare Earths Limited

("Rainbow" or "the Company")

LSE: RBW

 Rainbow Confirms Successful Development of Rare Earths Extraction Flowsheet

Rainbow Rare Earths confirms the development of a process flowsheet to extract rare earth elements efficiently from the phosphogypsum stacks at the Company's Phalaborwa Project in South Africa. This innovative process has been developed by Rainbow in collaboration with K-Technologies, Inc., USA ("K-Tech"), following extensive test work carried out at ANSTO Minerals, Australia, and at K-Tech's facilities in Florida, U.S.A.

Historically, the extraction of rare earths from phosphogypsum has proven technically, environmentally and economically challenging. However, Rainbow and K-Tech have developed a process flowsheet at Phalaborwa, underpinned by comprehensive test work, which successfully delivers an overall recovery of between 65% to 70% of the contained rare earths. This compares very favourably to the overall recovery of separated rare earth oxides via standard processes. Importantly, the process employs standard, proven equipment and readily available reagents in a novel combination. Rainbow and K-Tech will jointly patent the process with a view to applying this to further rare earths projects.

Following leaching of the phosphogypsum with sulphuric acid and subsequent rapid concentration of the rare earths in the pregnant leach solution, the concentrated rare earths solution is upgraded in K-Tech's proprietary continuous ion exchange ("CIX") and continuous ion chromatography ("CIC") process to deliver high-purity oxides of the target magnet rare earths, namely neodymium, praseodymium, dysprosium and terbium.

CIX and CIC have both been applied commercially in multiple applications since their development in the 1980s. These processes are now found globally in the food, biotech, chemical, water treatment, pharmaceutical and mining industries. Several of these industrial installations are found in South Africa.

The CIX/CIC process has several economic and environmental advantages over the conventional solvent extraction route, which include:

·    Nine process stages are required for the CIC separation, versus hundreds of stages in the solvent extraction ("SX") method depending on the desired product mix;

·    No hazardous or toxic solvents are required, whereas they are integral to the SX process;

·    Capital and operating costs are significantly lower for CIX/CIC compared to SX; and

·    Working capital requirements for CIX/CIC are minimised when compared to SX, due to the shorter time required for the production and delivery of saleable product.

Now that this important milestone has been successfully delivered, Rainbow looks forward to completing the technical feasibility study, which is expected to demonstrate this to be one of the lowest cost global producers of separated rare earth oxides.

Rainbow Rare Earths CEO, George Bennett, commented: "Working closely with K-Tech, we have been able to identify and confirm a novel process which will allow us to recover valuable rare earth oxides in a low capex and opex manner from phosphogypsum.  We are now in the process of jointly patenting this intellectual property with K-Tech and believe it will allow us to secure additional rare earths opportunities, such as the previously announced collaboration with a major chemicals group in South Africa.

Importantly, whilst the configuration of this new flowsheet is innovative, each individual stage is well tested on a commercial basis, with the required equipment and reagents being readily available.

Since introducing Phalaborwa to our portfolio in December 2020, we have always indicated that we believe it to be an exciting and near-term development opportunity to produce critical rare earths required for the green energy transition. The confirmation of an efficient and economic rare earths extraction flowsheet for the Project represents within 18 months a remarkable achievement for our business and underlines the significant amount of work carried out at the Project to date."

**ENDS**

Market Abuse Regulation ("MAR") Disclosure

This announcement contains inside information for the purposes of Article 7 of the Market Abuse Regulation (EU) 596/2014 as it forms part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018 ("MAR"), and is disclosed in accordance with the Company's obligations under Article 17 of MAR.

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Notes to Editors:

About K-Technologies Inc.:

K-Tech is a chemical process development and applications company serving the minerals and chemicals industries. K-Tech specialises in the development of process technologies that require unique recovery and/or component separation demands, especially those related to continuous separation methodologies. K-Tech has extensive knowhow and experience of separation processes involving continuous ion exchange, continuous ion chromatography and advanced sorption techniques as they apply to a variety of chemical and environmental applications.

About Rainbow Rare Earths:

Rainbow's strategy is to become a globally significant producer of rare earth metals. NdPr and Dy are vital components of the strongest permanent magnets used for the motors and turbines driving the green technology revolution. Analysts are predicting demand for magnet rare earth oxides will grow substantially over the coming years, driven by increasing adoption of green technology, pushing the overall market for NdPr and Dy into deficit.

The Phalaborwa Rare Earths Project, located in South Africa, comprises an Inferred Mineral Resource Estimate of 38.3Mt at 0.43% TREO contained within gypsum tailings stacked in unconsolidated stacks derived from historic phosphate hard rock mining and processing. High value NdPr oxide represents 29.1% of the total contained rare earth oxides, with economic Dysprosium and Terbium oxide credits enhancing the overall value of the rare earth basket in the stacks.  The rare earths are contained in chemical form in the gypsum stacks, which is expected to allow high-value separated rare earth oxides to be produced with lower operating costs than a typical rare earth mineral project.

The Company's Gakara Project in Burundi has produced one of the highest-grade rare earth concentrates in the world (typically 54% TREO) through trial mining operations. The Gakara basket is weighted heavily towards NdPr, which account for approximately 19.5% of the contained TREO and 85% of the value of the concentrate. The Gakara project is currently on care and maintenance at the request of the Government of Burundi.