Rainbow Rare Earths Ltd. has now built and commissioned a pilot plant, and pilot-scale operations have begun at the Phalaborwa project in South Africa.
The company said the pilot plant, developed using its intellectual property, will operate the fully optimised Phalaborwa leach circuit. It will produce pregnant leach solution for a pilot-scale continuous ion exchange and impurity removal circuit.
Rainbow noted that the pilot operation will also deliver a bulk feed sample for off-site solvent extraction test work. It said this will confirm the separation process to deliver separated neodymium and praseodymium oxide and a SEG+ Group product at more than 99.5% purity.
“This new piloting operation is the final phase of process test work for Phalaborwa, as it will demonstrate the project flowsheet that has been considerably updated over the past 18 months via a number of key optimisations,” said chief executive George Bennett.
The pilot plant is operating at Rainbow’s in-house laboratory premises located at Mintek in South Africa. Rainbow said this is the second pilot plant it has run. It said progress over the past 18 months has been focused on finalising the Phalaborwa flowsheet.
Rainbow outlined changes since the first pilot concluded in mid-2024. It said it reduced volumetric flow from the leach circuit to the separation circuit by incorporating continuous ion exchange for impurity rejection. It also cited subsequent impurity precipitation steps.
The company said large-scale locked cycle tests fully optimised the leach process. It said the leach process was reduced from three stages to two. It said residence time was reduced from 32 hours to 8 hours. It also cited fewer filters and lower leach heating requirements.
Rainbow guided that the pilot plant will run through H1 2026, with data underpinning process design for the definitive feasibility study. The pilot work will also support third-party validation for project finance, it noted.
