King River Resources Ltd (ASX:KRR) has tabled its new definitive feasibility study (DFS) strategy, considering how it will produce its ultra-high-purity aluminium precursor compound, known as type 1, at its proposed Kwinana facility in WA.
The precursor compound, which grades at the 5N or 99.999% purity level, can be used to produce 4N, or 99.99% high purity alumina (HPA) using King River’s proprietary ARC process.
Down the track, the company hopes to become a global producer of 4N HPA at its flagship hub in Kwinana’s industrial zone.
However, as part of the DFS update, the company considers pivoting its stage one strategy towards producing high-value aluminium precursor compounds that can be used to make lithium-ion battery cathodes.
By going down this path, King River hopes to leverage its existing intellectual property portfolio and reduce its capital and operating costs to generate better financial returns.
Following a series of test-work programs, the ASX-lister intends to make a final decision on a stage one operation that only uses the type 1 precursor compound, meaning high purity alumina production could be deferred to stage two.
Pilot plant under construction
Currently, King River is building a mini pilot plant to demonstrate its ARC HPA refining process at a larger scale and produce batch marketing samples.
Most of the component parts have been delivered, with some long-lead items pending final product certification.
Mass, temperature and timing measurements are being compiled from scaled-up laboratory tests to help modify the design and address reagent and product handling issues.
KRR has also started sourcing information on the various precursor needs from end-users and will complete further investigations through international market agencies.
Further metallurgical test-work has also continued to optimise the ARC process, including:
- Further refining the type 1 precursor product to reduce remaining contaminants;
- Desiccation/drying experiments to increase the aluminium content of type 1 precursor and improve its flowability in the calcination process;
- Low-temperature trials on the new 1500°C rotary tube furnace, used for the HPA calcination stage of the process, to establish flow rates and improve the removal of off-gases.
Como Engineers have also been engaged to rescope a modular process design for an initial precursor-only refinery.
Producing precursor compound
As outlined in King River’s pre-feasibility study, announced in mid-June, a very high purity type 1 precursor is calcined to produce HPA product at more than or equivalent to 4N (or 99.99%) purity.
More broadly, different specifications of precursor types do have other high-value applications for battery component manufacture.
This means the value of these bespoke precursors can exceed the value per tonne of standard HPA product, even though the manufacturing process is simpler and the unit cost is cheaper.
Therefore, in parallel to its other ongoing studies, KRR will consider opportunities to reduce the initial scale of the first commercial operation, thereby reducing capital and operating costs.
Laboratory test-work
Medical laboratory Source Certain International (SCI) is currently investigating whether type 1 precursor can also be used to produce precursor cathode active materials (P-CAM), an intermediate mixed metal hydroxide used to make lithium-ion battery cathodes.
KRR is targeting P-CAMs with nickel-cobalt-aluminium (NCA) and nickel-cobalt-manganese-aluminium chemistries, which are forecast to dominate the lithium-ion battery electric vehicle market through to 2030.
So far, SCI has completed two experiments to produce NCA-type P-CAM.
The results to date have been encouraging, although more test-work, sizing analyses and morphological studies are required.
That’s because the process controls needed to make P-CAMs are complex — the final product’s quality can only be determined after converting the P-CAM to CAM by adding lithium, then building and testing the lithium-ion battery cell.
Experiments three and four to generate NCA-type P-CAM are currently underway.
Ultimately, adding aluminium into the CAM plays a key safety role and increases the lifecycle of the lithium-ion batteries by improving the physical, thermal and cycling stability of the cathode for a small capacity loss.
Despite this opportunity, KRR maintains it does not aim to become a P-CAM manufacturer, but rather hopes to supply its precursor as the high purity aluminium source to this expanding market.