Can OD6’s Acid Savings Secure Splinter Rock’s Rare Earth Future?

Nanofiltration – A Game Changer for Rare Earth Processing

OD6 Metals has announced a significant technological advancement at its Splinter Rock Rare Earth Project in Western Australia. By integrating nanofiltration (NF) technology into its heap leach processing flowsheet, the company has achieved an outstanding 84.5% recovery of hydrochloric acid. This breakthrough reduces acid consumption by over 80%, a major operating cost driver, and promises to materially improve the project's economics.

Nanofiltration, a membrane filtration process that selectively separates substances based on size and charge, is commonly used in water purification. Its application in mining, particularly for acid recovery, is innovative and offers multiple benefits including lower energy use, reduced downstream equipment size, and suitability for remote operations.

Economic and Operational Impacts

The acid recovery translates into a dramatic reduction in the volume of liquid requiring treatment in the impurity removal circuit; down by 69%. This shrinkage allows for a smaller, less costly impurity removal setup, cutting both capital and operating expenditures. Importantly, the process achieves these savings without any loss of rare earth elements, with 94% of these elements concentrated for further processing.

OD6’s Managing Director Brett Hazelden highlighted that the switch from traditional tank leaching to heap leaching, combined with nanofiltration, simplifies the processing infrastructure by eliminating the need for leach tanks, thickeners, and complex solid-liquid separation equipment. This simplification further reduces costs and operational complexity.

Resource and Recovery Highlights

The Inside Centre Deposit remains the cornerstone of the project, boasting an Indicated Resource of 119 million tonnes at 1,632 parts per million total rare earth oxides (TREO). Heap leach recoveries for magnetic rare earth elements (MagREE) stand at a robust 79%, with neodymium and praseodymium recoveries consistently around 80%, surpassing benchmarks from comparable clay-hosted rare earth projects.

These results underscore the potential for Splinter Rock to become a leading rare earth operation in Australia, leveraging both scale and grade. The current resource covers less than 10% of the tenement area, indicating significant upside from further exploration.

Next Steps and Future Outlook

OD6 is finalising additional metallurgical testwork, including impurity removal trials and ion exchange assessments, to refine the processing flowsheet. An optioneering study by CPC Engineering is underway to integrate these findings and optimise the overall project design. The company anticipates completing this work within the current quarter.

While the nanofiltration results mark a pivotal milestone, the full economic impact will depend on the successful integration of downstream processes and scale-up. Investors will be watching closely as OD6 advances towards pilot scale testing and further resource expansion.