PMET Resources has achieved over 97% caesium extraction from pollucite concentrate using sulphuric acid leaching at SGS Canada, while parallel proprietary testwork with Koch Technology Solutions advances value-added caesium chemical pathways.
- Bench-scale caesium extraction surpasses 97% recovery
- Effective impurity removal including aluminium demonstrated
- Potential rubidium by-product identified for future recovery
- Koch Technology Solutions shows selective caesium loading in proprietary flowsheet
- Preliminary Economic Assessment incorporating caesium due Q4 2026
High Recovery from Pollucite Concentrate Validates Extraction Approach
PMET Resources Inc. (ASX:PMT) has reported a significant milestone in its critical minerals development with bench-scale testwork achieving more than 97% caesium extraction from pollucite concentrate sourced from its Shaakichiuwaanaan Property in Quebec. Conducted at SGS Canada's Lakefield facility, the conventional sulphuric acid leaching process not only delivered high caesium recovery but also demonstrated efficient removal of key impurities such as aluminium, a critical factor for downstream chemical processing.
The pollucite concentrate feed, assaying approximately 12% Cs2O and produced via X-Ray Transmission ore sorting from the Vega Caesium Zone at the CV13 Pegmatite, was subjected to leaching at varying temperatures up to 120°C. The testwork maintained low extractions of impurities while recovering caesium consistently between 97% and 98%, underpinning the robustness of the extraction conditions identified.
Parallel Proprietary Processing Advances Value-Added Caesium Products
Alongside SGS Canada’s conventional program, PMET is collaborating with Koch Technology Solutions (KTS), a division of Koch Inc., to explore advanced proprietary processing routes. Early results from KTS's Phase 1 testwork indicate highly selective and strong caesium recovery using their proprietary flowsheet, employing both synthetic and live Pregnant Leaching Solutions. This approach aims to produce a range of value-added caesium chemicals, complementing the conventional extraction pathway.
The KTS program currently uses around 6 kg of pollucite concentrate and is set to progress to Phase 2, focusing on producing gram-scale quantities of caesium derivative products, aligning with PMET’s strategy to unlock maximum value from its caesium resource.
Strategic Resource and Economic Development at Shaakichiuwaanaan
PMET’s Shaakichiuwaanaan Property hosts the world’s largest in-situ pollucite-hosted caesium pegmatite resource, with indicated and inferred Mineral Resources totaling approximately 2.39 million tonnes at grades of 4.40% and 2.40% Cs2O respectively. This caesium resource sits alongside significant lithium and tantalum mineralisation, positioning the project as a critical minerals hub.
The company plans to leverage these extraction advancements into producing high-purity caesium salts such as Cs-sulphate, Cs-carbonate, and Cs-formate, with potential for rubidium carbonate by-product recovery. These efforts are timed alongside a Preliminary Economic Assessment (PEA) scheduled for completion in Q4 2026, which will integrate lithium, caesium, and tantalum economics, complementing the lithium-only Feasibility Study also due that quarter.
Implications for Critical Minerals Supply and Project Development
Caesium is a niche but strategically important element used in specialty chemicals, electronics, and emerging energy applications. PMET’s demonstration of high-recovery extraction and impurity control at bench scale is a critical step toward commercialising its caesium resource. The identification of a rubidium by-product opportunity also hints at further value potential from the tailings streams, though this requires additional validation.
PMET’s dual-path approach, conventional acid leaching and proprietary flowsheet development, provides flexibility and risk mitigation as it advances toward pilot-scale production. The company’s integration of these metallurgical programs with ongoing lithium and tantalum development underlines the Shaakichiuwaanaan Property’s potential as a multi-commodity critical mineral project.
Bottom Line?
PMET’s strong caesium extraction results and parallel processing developments set the stage for advancing value-added chemical production, with key economic assessments due later this year.
Questions in the middle?
- Will PMET successfully scale bench-scale caesium extraction to pilot and commercial production?
- How material could rubidium by-product recovery become in the project’s overall economics?
- What partnerships might PMET pursue to commercialise value-added caesium chemical products?