Rainbow Rare Earths Advances High-Purity Separation at South African Phalaborwa Project
Rainbow Rare Earths has reported a significant technical breakthrough at its Phalaborwa project, achieving rare earth separation feedstock of unprecedented purity through its proprietary continuous ion exchange (CIX) process. The development marks a critical milestone in the company’s ambition to establish a low-cost, near-term source of strategic minerals outside of China’s dominant supply chain.
The London-listed firm said its optimised laboratory work in Johannesburg has consistently produced mixed rare earth carbonate (MREC) samples with total rare earth oxide (TREO) concentrations exceeding 55 per cent—well above the industry’s typical benchmark of 42 per cent. The purified product, which now averages over 93 per cent TREO purity across multiple test campaigns, positions Rainbow’s feedstock among the highest-grade MREC specifications globally.
The achievement is seen as pivotal in advancing the final separation phase of the Phalaborwa flowsheet, with updated modelling and cost analysis now underway. The company confirmed that the purified feedstock will underpin its separation strategy, targeting individual rare earth oxides (REOs) with purity levels approaching 99.5 per cent.
Rainbow’s Phalaborwa project is unique in its approach, extracting rare earths from phosphogypsum waste—a by-product of fertiliser production—rather than conventional mining. This method significantly reduces both capital intensity and environmental risk, while accelerating the development timeline.
The company said its Definitive Feasibility Study (DFS) for the primary leach flowsheet, which accounts for approximately 85–90 per cent of total project capital expenditure, is progressing well. Recent trade-off studies are being incorporated into the DFS and are expected to yield further savings in both capital and operating costs.
We caught up with CEO George Bennett at the 2024 Mining Indaba conference in Cape Town. He provided an update on Rainbow’s operations, but also told us about the many uses of rare earths and why they are so important in the global energy transition.