AR3 Validates Rare Earth Hydroxide Production at Koppamurra Pilot

Australian Rare Earths Limited (ASX: AR3) has advanced its Koppamurra project from ore extraction to intermediate product generation. The company reported that the first of four planned heap leach column cycles, utilizing approximately eight tonnes of ore, produced around 5,000 liters of Pregnant Leach Solution at target recovery rates. This initial stream was successfully processed through a continuous three-stage precipitation circuit to yield Mixed Rare Earth Hydroxide, marking a transition from raw extraction to concentrated product recovery at the ANSTO facility in Sydney.

The pilot program, which began with the commissioning of agglomeration and heap leach circuits in August 2026, now focuses on validating the downstream flowsheet. The primary objective of this phase is to generate the operational and engineering data required to support the design of a Definitive Feasibility Study. By demonstrating continuous production of the hydroxide intermediate, the company aims to de-risk the commercial processing model before final product refinement.

Precipitation Circuit Performance

The recent campaign involves transferring the leach solution into a continuous reactor system where neutralizing agents precipitate rare earths into a solid hydroxide form. This stage validates the recovery of rare earth elements from the liquid phase into a manageable solid intermediate. The process also evaluates the performance of thickening, filtration, and washing circuits under continuous operating conditions, ensuring that solid-liquid separation methods are robust enough for commercial-scale equipment sizing.

Key performance metrics during this phase include optimizing reagent consumption and stabilizing precipitation conditions. The material remaining after processing, known as barrens, is being evaluated for potential recycle opportunities within the broader commercial flowsheet. This comprehensive validation ensures that the entire downstream sequence, from precipitation to final washing, functions cohesively to produce a consistent intermediate product.

Path to Customer Qualification

The Mixed Rare Earth Hydroxide produced in this stage serves as the precursor for final product qualification. The company plans to refine a portion of this intermediate material into Mixed Rare Earth Oxide samples. These samples will be shared with prospective offtake partners to initiate customer qualification processes. This step is critical for securing long-term offtake agreements and validating the market acceptance of the Koppamurra product stream.

According to GN auto stocks materials, the pilot operation is scheduled to continue through December 2026. This extended campaign allows for the accumulation of sufficient engineering data to finalize the Definitive Feasibility Study. The successful transition to producing a concentrated rare earth intermediate confirms that the Koppamurra flowsheet can handle continuous processing, a key requirement for commercial viability.

Engineering Data for Commercial Scale

The data generated from the current pilot phase directly informs the selection and sizing of commercial-scale equipment. By testing the precipitation, thickening, and filtration circuits under realistic operating conditions, the company is deriving the design criteria necessary for the full-scale plant. This approach reduces technical uncertainty and provides a solid foundation for the financial modeling required in the Definitive Feasibility Study.

The pilot program represents a significant de-risking milestone for the project. Moving beyond heap leaching to produce a saleable intermediate product demonstrates the technical feasibility of the entire processing chain. As the company progresses toward final Mixed Rare Earth Oxide production, the accumulated operating data will be central to attracting investment and securing offtake commitments for the Koppamurra rare earths project.