JOHANNESBURG (miningweekly.com) – South Africa-functioning and London-listed Rainbow Rare Earths said on Wednesday, October 21, that it would be the first company to deliver a low-cost, low-capital-intensity, commercial solution to recover high-valued rare earth elements (REEs) from phosphogypsum, a phosphoric acid waste dumped in South Africa's Limpopo province.

Rainbow highlighted that it is now close to creating distinctive intellectual property (IP).

“The decision that shaped the year more than any other was establishing our own world-class laboratory in Johannesburg,” Rainbow Rare Earths CEO George Bennett stated in a special letter to shareholders.

Laboratory success has resulted in the commissioning of a pilot plant and Canadian company Neo Performance Materials has been chosen to provide the solvent extraction solution that enables the production of separated neodymium, praseodymium oxide and samarium-europium-gadolinium carbonate REEs.

“Initial standalone solvent extraction bench and pilot test work to validate the final step in our process is already underway at Neo’s facility in Estonia using high-grade rare earth solution from Phalaborwa,” Bennett reported.

An integrated pilot plant for the solvent extraction separation circuit would then, he said, be operated in Rainbow’s Johannesburg laboratory to underpin the engineering and design for the definitive feasibility study (DFS) for completion next year.

Supported by current test work, a prefeasibility study, targeted for publication in the last quarter of this year, would define the final products, processes and the waste streams with sufficient certainty to begin financing and restart permitting workstreams in earnest.

The permitting process would be carried out in parallel with DFS finalisation. “South Africa has a well-established permitting timeline, which does not need to wait for a DFS to be completed,” Bennett pointed out, while adding that “every month we can bring it forward is a month gained”.

Rainbow stated that responsible production remained at the heart of its business model and that cleaning up the legacy the Phalaborwa environmental issue would accompany recovery of the critical REEs essential to the green energy transition, defence and other advanced technologies.

As reported earlier by Mining Weekly, the pursuit of value from waste will have the added benefit of cleaning up an old opencast mine, a dormant Sasol phosphoric acid plant, and two unlined environmentally hazardous gypsum stacks.

In his statement to shareholders, nonexecutive chairperson Adonis Pouroulis described REEs as being essential for both national security and economic resilience.

“They are found in the products we rely on every day, and in the emerging and advanced technologies that will define the decades ahead, from electric vehicles and robotics to defence systems and the wider green energy transition.

“Our strategy, to develop low-cost, low-capital-intensity projects that recover REEs from phosphogypsum, a by-product from the production of phosphoric acid, using our own IP, rather than through conventional hard-rock mining, positions us well to benefit from this structural shift.

“Over the course of the year, our understanding of the process to extract REEs from phosphogypsum has increased substantially. The key value driver has always been getting the flow sheet right, so that it can in time be rolled out to other phosphoric acid opportunities globally.

“We are now close to finalising our flow sheet, creating unique IP to extract valuable REEs from a waste product,” Pouroulis reported.

Cash held by Rainbow as at June 30 was $12.9-million.