In a groundbreaking development in the rare earth sector, Rainbow Rare Earths has successfully completed the group separation of rare earth elements through initial ion exchange test work conducted in the USA. This achievement represents a critical advancement in the rare earth oxide separation process, paving the way for the production of individual rare earth oxides, crucial for various high-tech and green energy applications.
Rainbow Rare Earths’ back-end piloting campaign has primarily focused on producing high-purity neodymium and praseodymium (NdPr) oxide. This effort is part of a broader initiative to also separate dysprosium (Dy) and terbium (Tb) oxides, elements essential for the manufacture of permanent magnets used in electric vehicles and wind turbines. Additionally, the company has made significant strides in the potential group separation of samarium (Sm), europium (Eu), and gadolinium (Gd), presenting an opportunity to create a combined oxide product and diversify its revenue streams.
The process at the core of these advancements is the innovative use of continuous ion exchange (CIX) and continuous ion chromatography (CIC) technology. Developed by K-Tech for the rare earth industry, this method stands out for its departure from traditional solvent extraction techniques, which rely on toxic and flammable solvents and diluents and involve over a hundred separate stages. Instead, the CIX and CIC processes offer a more efficient and environmentally friendly alternative for producing separated rare earth oxides.
Rainbow and K-Tech have identified a cerium-depleted mixed rare earth carbonate as the ideal feedstock for this advanced back-end process. The mixed rare earth carbonate, produced from the phosphogypsum at the Phalaborwa project, is currently being tested at both K-Tech and Mintek facilities. This high-grade feedstock is anticipated to enhance the efficiency of the separation circuits significantly.
George Bennett, CEO of Rainbow, expressed satisfaction with the progress made in both the front-end and back-end processes. “The back-end process is on track to deliver separated high-purity rare earth oxides of NdPr, Dy, and Tb,” Bennett stated. He further highlighted the potential for adding another saleable product to Rainbow’s portfolio at minimal cost, thanks to positive separation results in the chromatography circuit for the SEG group of rare earth oxides.
The ongoing pilot plant test work at K-Tech is focused on optimizing the chromatography process to produce a 99.5% pure NdPr product. Subsequent CIC testing will aim to separate and purify Dy and Tb oxides. Additionally, the potential production of a separated and purified SEG oxide product is under evaluation, with initial projections suggesting that Phalaborwa could annually produce 500 tonnes of a saleable SEG product. This would complement the previously announced residual gypsum off-take, offering another revenue stream with minimal capital and operating expenses.
Rainbow Rare Earths’ efforts at Phalaborwa are set to produce four critical rare earth elements—NdPr, Dy, and Tb—key to the transition to a green economy. These elements are vital for permanent magnets in electric vehicles and wind turbines, as well as in advanced technologies used in strategic defense applications. The SEG rare earth elements—samarium, europium, and gadolinium—also find essential uses in magnets, optical displays, and medical and nuclear applications, respectively.
This milestone by Rainbow Rare Earths marks a significant step forward in securing a sustainable supply of critical minerals necessary for the global transition to green energy and advanced technological applications.
