Everest Metals (ASX: EMC) Advances Mt Edon Rubidium Pilot Path

Everest Metals Corporation has moved its Mt Edon rubidium processing technology closer to pilot-scale development after laboratory testwork achieved recoveries of up to 90% from representative project material.

The work, undertaken by Edith Cowan University, also cut water use during leaching by 60% by reducing the liquid-to-solids ratio from 10:1 to 4:1. Leaching was conducted at room temperature, removing the energy requirement for heating water while producing a more concentrated solution for downstream purification.

The results advance several parts of the proposed processing flowsheet, but continuous roasting remains a key technical hurdle. Initial rotary-kiln trials processing about 60 kilograms of ore and reagents returned lower and variable rubidium recoveries of approximately 50% to 60%, compared with 80% to 90% in batch tests.

ECU attributed the weaker continuous-processing results to salt melting near the kiln entrance, which restricted material movement. Modifications to the feed arrangement and handling procedures are being implemented, with further tests required to demonstrate improved consistency.

Purification process shows repeatability

Everest’s Direct Rubidium Extraction process consistently reduced the potassium-to-rubidium ratio to approximately 1.5–2:1 in a single purification pass across at least 20 cycles. Separating the two elements is difficult because of their similar chemical properties.

Bipolar membrane electrodialysis also removed the desorption agent while retaining rubidium in solution. The process incorporates technology covered by Everest’s international patent application and allows the solution to be recirculated through the purification medium.

Based on measured selectivity coefficients, ECU estimates the integrated process could produce rubidium at purity exceeding 98%. That remains a projected result and requires validation through further integrated testwork.

Everest has separately validated production of its in-house purification medium at a multi-hundred-gram scale. It has procured several hundred kilograms of precursor material and is commissioning equipment intended to support continuous production at several kilograms per day.

Scale-up work ahead

The processing program is supported by the Minerals Research Institute of Western Australia and the Australian Economic Accelerator Ignite program. Everest and ECU secured $490,500 through the latter program in January 2026 to help move the technology from laboratory validation towards a prototype operating under near-commercial conditions.

Mt Edon, located near Paynes Find in Western Australia, has an Indicated and Inferred Mineral Resource of 4.3 million tonnes grading 0.23% rubidium oxide and 0.10% lithium oxide. The estimate contains 9,800 tonnes of rubidium oxide and includes a higher-grade subset of 1.56 million tonnes at 0.31% rubidium oxide.

The next work will include additional kiln trials, integrated purification testing, engineering scoping and a preliminary operating-cost estimate based on bench-scale data. Everest also plans to progress Mining Proposal approvals and seek grant funding for a pilot plant. Commercial viability has not yet been established, with larger-scale performance and processing costs still to be demonstrated.