LSE-listed Rainbow Rare Earths reports that, in the first half of this year, work at its Phalaborwa project in Limpopo, South Africa, continued to focus on optimising and simplifying the flowsheet to enhance the plant operability and reduce risk when moving to commercial scale.

In an update to the market on the definitive feasibility study (DFS) that is under way at the project, the company notes that Phalaborwa will be the first to commercially recover rare earth elements from phosphogypsum, which is a waste material from phosphoric acid production.

As a result of this plan, many of the costs, risks and long timescales associated with traditional mining projects are expected to be eliminated.

The pilot plant has been operating successfully throughout the first half of this year and, having demonstrated an ability to produce a commercial intermediate product, optimisation work has continued with the solvent extraction separation process using innovative technologies for rare earth separation.

Rainbow’s testwork and pilot plant operations have optimised and simplified the flowsheet, with 75% of the flowsheet now in the engineering phase of the DFS.

The final optimisation of the solvent extraction circuit is currently under way.

“By establishing our own dedicated metallurgical and analytical laboratory in Johannesburg, Rainbow has been able to complete major testwork to optimise capital and operating costs for the Phalaborwa process while simplifying the flowsheet and improving operability.

“This approach to testwork has allowed for very significant changes to be made to the flowsheet, all of which benefit the project. Our focus now is on integrating the [solvent extraction] circuit into the overall process and we look forward to further updates in due course which will demonstrate that Phalaborwa continues to represent a near-term producer of light and heavy rare earths, right at the bottom of the industry cost curve,” comments Rainbow CEO George Bennett.

The optimisation work with Rainbow Rare Earth’s technical partner has resulted in an update to the flowsheet, further simplifying it and enabling the production of a mixed rare earths feed.

This will feed directly into the solvent extraction separation process from the continuous ion exchange circuit in a more cost-effective manner without the need to produce the intermediate product first.

The final product from the solvent extraction circuit will be separated neodymium praseodymium oxide and samarium, europium and gadolinium at 99.5% purity, as well as commercial quantities of products which include dysprosium, terbium and yttrium that are expected to unlock higher returns than the intermediate product alone.