American Rare Earths Ltd (ASX:ARR, OTCQB:ARRNF) has achieved a major metallurgical milestone at its Halleck Creek Rare Earths Project in Wyoming, completing impurity removal neutralisation tests that significantly de-risk a historically challenging stage in processing allanite-based rare earth elements.
The company reported that impurity removal tests conducted by SGS Canada yielded exceptional results, effectively eliminating contaminants such as iron, titanium, aluminium and silica from the leachate solutions while producing minimal amounts of unwanted byproducts like gypsum and silica gel.
These results point to important operational advantages, including reduced rare earth yield loss, fewer processing steps and potentially lower capital and operating costs.
Key processing results
Using magnesium oxide (MgO) as the optimal neutralising reagent, the tests achieved:
- 99.8% removal of iron, 99.4% titanium and 92.9% thorium;
- 89% silica and 40.5% aluminium removed during primary neutralisation;
- More than 96% aluminium and 95% titanium removed in secondary neutralisation; and
- Rare earth element losses of less than 1% during primary neutralisation.
The tests were performed at SGS’s Lakefield facility in Ontario and form part of the hydrometallurgical processing flowsheet for the project’s upcoming pre-feasibility study.
American Rare Earths said the breakthrough effectively resolves a technical hurdle that has historically limited the economic processing of allanite-based ores, such as Halleck Creek’s, where unwanted compounds typically complicate recovery and increase costs.
Next steps in testing
With hydrometallurgical testing nearing completion, SGS will now produce a mixed rare earth oxalate by precipitating the rare earths with oxalic acid. This will then be calcined to create a mixed rare earth oxide — a precursor for the solvent extraction stage used to separate individual rare earth oxides.
These final tests are expected to conclude before year-end, with results to be incorporated into the Halleck Creek pre-feasibility study. In parallel, bulk samples from the project’s test pit are undergoing comminution optimisation testing with Fl Smidth, Loesche and Weir (Corem).
Strengthening US rare earth independence
Through its Wyoming Rare (USA) Inc. subsidiary, American Rare Earths is advancing the Halleck Creek project as a cornerstone of US critical mineral supply security. Located on Wyoming state land, the project benefits from cost-efficient open-pit mining potential and streamlined permitting in a mining-friendly jurisdiction.
With onsite processing and separation facilities planned, the project is designed to reduce US dependence on imported rare earths — particularly from China — and to meet growing domestic demand for the materials used in permanent magnets, defence systems and clean energy technologies.