King River Resources Ltd (ASX:KRR) has progressed the pre-feasibility study (PFS) for its Speewah Speciality Metals Project in the East Kimberley in Western Australia with the primary focus on the production of high purity alumina (HPA).
Future potential Speewah co-products vanadium (V2O5), titanium (TiO2) and iron (Fe oxide) are not included as part of this initial study.
The following PFS developments have been the focus of test-work and studies:
- Simplifying the purification circuit to produce a high purity HPA precursor that now involves only a crystallisation process without the need for a second stage ion exchange circuit, (this has increased the overall recovery requiring changes to both the engineering design and also the mining study as less tonnes need to be processed);
- Calcination of the HPA precursor (at 1200°C) to ensure no contamination is introduced and 4N (99.99% Al2O3) HPA is produced; and
- Further phase tests on initial XRD analysis which showed the alumina is converted to the stable alpha form suitable for LED and battery separator applications;
Larger final sample sizes are now being generated for more comprehensive test-work and analysis and independent umpire assay laboratory and protocols have been selected.
The following hydrometallurgical test-work and studies are underway:
- The plant and infrastructure design and costings by Como Engineers are waiting on the final model validation and review; and
- Calcination of larger samples are pending the resolution of some final contamination issues for verification assay.
The PFS has assumed a Kimberley focus that would produce HPA and the company aims to release the PFS as soon as practicable on completion of these remaining outcomes.
HPA process route
In parallel to completing the PFS, the company has been evaluating the potential of using its HPA process route on alternative aluminium feedstocks.
Recent test-work has demonstrated that a high purity HPA precursor can readily be made.
The implication is that start-up HPA development may be initially focused around a Perth industrial estate, without the immediate capital and permitting needs to be building a Kimberley-based acid plant adjacent to a mining and processing operation.