Name of the Project
Phalaborwa rare earths project.

Location
Limpopo, South Africa.

Project Owner/s
London-listed Rainbow Rare Earths announced the signing of a binding agreement with Bosveld Phosphates for the co-development of the Phalaborwa rare earths project in November 2020.

On completion of a prefeasibility study (PFS), 70% of the project will be held by Rainbow and 30% by Bosveld, with a mechanism included to allow for Rainbow’s joint venture ownership to vary from 60% to 85%, depending on the results of the PFS.

Project Description
Rainbow Rare Earths and Bosveld Phosphates intend to jointly develop and process rare-earth elements from the gypsum contained in two stacks at the project site.

The project comprises an estimated 35-million tonnes of gypsum, resulting from historical phosphate hard-rock mining and containing rare-earth elements, with an estimated average in situ grade of 0.6% total rare-earth oxides (TREOs) for about 210 000 t of TREOs, with neodymium and praseodymium expected to constitute about 30% of the TREOs basket.

The reprocessing of these gypsum stacks carries significant environmental benefits, as it will redeposit clean, benign gypsum, which then has the potential for further use in the building and fertiliser industries.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
Not stated.

Capital Expenditure
Not stated.

Planned Start/End Date
Not stated.

Latest Developments
Rainbow Rare Earths has recorded initial results from the ongoing metallurgical testwork programme at the Phalaborwa project.

The programme is being undertaken by Australian company ANSTO Minerals.

Testwork has confirmed that the phosphogypsum is amenable to simple, direct leaching with low-cost sulphuric or hydrochloric acid without pretreatment.

Initial recoveries of rare earths greater than 70% have been achieved within 24 hours, which will be improved through further optimisations.

Moreover, it is expected that the production of high-value products (mixed rare-earth carbonate or separated rare-earth oxides) will be possible from the leach solution.

The testwork has also confirmed that the phosphogypsum contains exceptionally low levels of radioactive elements – uranium and thorium – when compared with other rare earth projects.

Radioactivity controls are expected to be required for the shipment of the rare-earth products and no expensive redeposition measures should be required for the leached phosphogypsum residue.

The testwork results, to date, support the expectations that a simplified processing flowsheet can be developed and optimised from the original flowsheet compiled by previous owner chemicals company Sasol. Rare earths will be able to be recovered without the high-cost, energy- and reagent-intensive mining, crushing, milling, primary beneficiation, cracking and uranium/thorium removal costs associated with a typical rare earth project.

The next phase of testing is focused on the optimisation of leach recovery and acid consumption, and the initial selective recovery of the rare earths from the leach solution.

“As we review further optimisation to increase the recovery of rare-earth elements and reduce reagent consumption, we will carry out a thorough cost/benefit analysis to ensure each step increases the overall value of the project,” CEO George Bennet has said.

“These initial testwork results confirm my belief that Phalaborwa . . . will probably be the fastest global rare earth development project to get to the mixed rare-earth carbonate-producing stage. 

Rainbow Rare Earths is targeting an accelerated timeframe for production delivery from Phalaborwa, which can be achieved only with simple processing requirements because of the unique nature of the project.  

The testwork has confirmed that the Phalaborwa tailings are expected to be benign, negating the need to manage multiple tailings facilities, which adds increased costs for many global rare earth projects. 

The concurrent rehabilitation of two historical gypsum stacks reduces the environmental footprint in an ecologically sensitive area.

Further work is planned to confirm the leach characteristic variability of the stacks to support a preliminary economic assessment for the project.

Further optimisation and processing development work will then be undertaken before the completion of a full feasibility study.

Key Contracts, Suppliers and Consultants
ANSTO Minerals (flowsheet process optimisation).

Contact Details for Project Information
Rainbow Rare Earths CEO George Bennett, cell +27 82 652 8526.