Rainbow Rare Earths (LSE:RBW) has simplified its Phalaborwa rare earths project flowsheet and advanced 75% of the process design to the engineering phase of its definitive feasibility study (DFS), with work on the final solvent extraction (SX) circuit still underway.
The South Africa-focused company, which is developing what it describes as the first commercial recovery of rare earth elements from phosphogypsum waste, has reworked the process significantly since its preliminary economic assessment (PEA), cutting the number of capital-intensive horizontal belt filters from 14 to 8 and reducing leach residence time from 32 to 8 hours.
A key change sees the intermediate product stage removed entirely, with a mixed rare earth feed now flowing directly from a continuous ion exchange (CIX) circuit into the SX separation process, which Rainbow says is more cost-effective.
The final SX output will include neodymium-praseodymium oxide and SEG+ Group at 99.5% purity, alongside commercial quantities of dysprosium, terbium and yttrium.
"By establishing our own dedicated metallurgical and analytical laboratory in Johannesburg, Rainbow has been able to complete major test work to optimise capital and operating costs for the Phalaborwa process whilst simplifying the flowsheet and improving operability," said CEO George Bennett.
Integration of the CIX circuit with the downstream SX process is the current project focus, with the SX circuit expected to move to the final engineering phase in due course.
