Rainbow, Mosaic partner on rare earths extraction in Brazil

Rainbow Rare Earths (LSE: RBW; US-OTC: RBWRF) has inked a memorandum of understanding with Mosaic (NYSE: MOS) to jointly study the viability of extracting rare earth elements (REEs) from the phosphate and potash minerals producer project in the Brazil.

The agreement sets out a potential collaboration to develop a process flowsheet to extract rare earth elements from Mosaic’s phosphogypsum stack in the Uberaba area of Minas Gerais.

Rainbow believes the Uberaba stack has a similar grade and make-up to that of its Phalaborwa project, in South Africa. Both operations, it said, involve a hard-rock carbonatite phosphate deposit being mined and processed into a phosphate slurry and then into phosphoric acid.

Rainbow and Mosaic expect to collaborate on the production of a preliminary economic assessment of the opportunity to extract rare earths.

“This agreement with Mosaic represents a major opportunity for Rainbow to apply the proprietary extraction technology developed in conjunction with K-Tech to become a multi-asset producer of rare earth elements from secondary sources,”Rainbow chief executive George Bennett said in the statement.

“We’ve made considerable strides over the years in advancing gypsum reuse – and this work is a natural extension of that,” senior vice president of Mosaic, Corrine Ricard, noted.

Rainbow said this collaboration could mean that simpler hydrometallurgical processes can be used to produce  separated and purified rare earth oxides.