King River Resources achieves >4N purity using KRR refining process on production runs with five HPA batches

King River Resources Ltd (ASX:KRR) has produced high-purity alumina (HPA) at >4N (99.99%) purity by calcining high purity precursor materials purified by the KRR refining process from an industrial chemical feedstock material available through domestic and international suppliers. The >4N purity results are from five HPA production runs completed by Source Certain International (SCI), previously TSW Analytical Pty Ltd, and were calculated by the addition of all the assayed element impurities then subtracted from 100%. Results Main contaminants in the HPA samples are potassium and iron, with varying amounts for calcium, chromium and niobium. The last three HPA batches (4, 5 and 6) reported HPA alumina grade >99.99% aluminium on the oxide basis where the individual elements have been converted to their oxide equivalent value as a per cent, then summed and subtracted from 100%. These >4N HPA grade results are due to improvements in the decomposition of the precursor during calcination which removed more of the volatile elements. Samples sent to Perth laboratory SCI has developed a new assay method that has eliminated some of the conventional reagents and process steps that introduced contamination and the method has also reduced the detection limits of most elements. A modified calcination and washing process has helped reduce silicon, chromium and iron contamination and volatile elements noted in previous test runs. HPA samples will be sent to an independent laboratory in Perth to verify the HPA purity using fusion-XRF and fusion-laser ablation assay techniques. These assays will help to ensure quality control and quality assurance and is an important step in completing the HPA Prefeasibility Study (PFS). A phase analysis is also planned to confirm the crystal structure is 100% alpha-alumina. Other pre-feasibility study outcomes KRR continues investigations for a downstream processing industrial site in the Kwinana area 30-40 kilometres south of Perth in Western Australia. This area is close to a skilled and productive workforce, hosts specialist centres for chemical and resource-based processing, marine engineering and shipbuilding, and has industrial land areas specifically set aside for companies wishing to invest in downstream processing and other heavy or strategic industrial activities, including the Lithium Valley concept plan. Como Engineers’ capex and opex estimates are pending some final cendor costings. On completion, the PFS documentation will be finalised for release to the market. A Mini-Pilot Plant to demonstrate the KRR process works at a larger scale for the definitive feasibility study and to produce market samples has also commenced. The process flowsheet and mass balances have been used to scale the mini-pilot plant and enquiries with vessel vendors are underway. KRR has already purchased a rotary tube furnace for the calcination stage of the process with delivery in about eight weeks.  Metallurgical test-work continues  Metallurgical HPA test work is continuing to further refine the KRR process with the current focus on improving the precursor product to simplify the final calcination stage. Test-work is also ongoing into extracting high purity vanadium and titanium products from the Speewah vanadium deposit suitable as intermediate products for battery and master alloy applications.