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- King River Resources has achieved >4N HPA production using its refining process.
- Industrial chemical feedstock material available from international and domestic suppliers was used for the HPA production.
- The new assay method is effective in eliminating many process steps and conventional reagents.
King River Resources Limited (ASX:KRR) continues to make major headways, the latest being the production of high purity alumina (HPA) at >4N (99.99%) purity.
The upbeat market update attracted strong investors’ interest, as KRR shares surged by over 27% on 25 March 2021.
KRR Directors are thrilled about the Company’s new process development, which can produce >4N purity HPA. The HPA batches were produced by calcination of high purity precursor materials, purified by the KRR refining process from an industrial chemical feedstock material, which is commonly available from international and domestic suppliers.
The next step is the release of the Prefeasibility Study (PFS), which is expected shortly.
A Snapshot of Results
Source Certain International (SCI) (erstwhile TSW Analytical Pty Ltd) completed five HPA production runs to get the >4N purity results. The results were calculated by adding all the assayed element impurities and then subtracting from 100%.
The HPA samples contain primary contaminants, including potassium (K), Iron (Fe), along with varying amounts of chromium (Cr), calcium (Ca) and niobium (Nb).
The HPA alumina grade of >99.99% Al2O3 on the oxide basis was reported from the last three HPA batches, with individual elements converted to their oxide equivalent value as a per cent, summed and then subtracted from 100%.
These >4N HPA grade results were achieved as a result of improvements in the precursor decomposition during calcination, which removed more of the volatile element.
An Effective Assay Method Developed
The new assay method developed by SCI is quite effective in eliminating some of the process steps and conventional reagents that earlier added to contamination. Furthermore, the method has proven successful in reducing the detection limits of most elements.
The new method includes a modified calcination and washing process that reduces silicon, chromium and iron contamination and other volatile elements observed in previous test runs.
The HPA samples will be sent to a Perth-based independent laboratory to verify the HPA purity through fusion-XRF and fusion-laser ablation assay techniques.
Moreover, the assays form a critical step for the HPA PFS completion, besides ensuring quality control and quality assurance. A planned phase analysis will be undertaken to confirm whether the crystal structure is 100% alpha-alumina.
A Sneak Peek at PFS Outcomes
Engineering Studies- Once Como Engineers manage to calculate Capex and Opex estimates, which are pending some final Vendor costings, the PFS documentation will be finalised for release to the market.
Kwinana Industrial Site- KRR has advanced investigations for Kwinana industrial site (WA), located 30-40 kilometres south of Perth.
Source: Copyright © 2021 Kalkine Media Pty Ltd, Data Source: KRR ASX update, dated 25 March 2021
Mini Pilot Plant and other Metallurgical Developments
In order to establish the efficacy of the KRR process at a larger scale for producing market samples and the Definitive Feasibility Study, the company has kicked off the development of a Mini-Pilot Plant.
The process flowsheet and mass balances have been utilised for scaling the mini-pilot plant, and enquiries with vessel vendors are underway. A rotary tube furnace has been already purchased to be used in the calcination stage of the process, and delivery is expected in around eight weeks. Notably, the mini-pilot work will not interfere the PFS release.
Meanwhile, metallurgical HPA testwork is in progress to further refine the KRR process. The current focus is on the improvement of the precursor product to simplify the final calcination stage.
Further testwork is being conducted for extraction of high purity vanadium and titanium products from the Speewah vanadium deposit appropriate as intermediate products for master alloy and battery applications.