ASX-listed Lithium Australia’s application for a US patent for one of its proprietary lithium extraction technologies, SiLeach, has been approved by the US Patent and Trademark Office. The Perth-based company also received a notice of acceptance from IP Australia for the same patent application, which is expected to be granted at the end of April.
SiLeach was developed in collaboration with the Australian Nuclear Science and Technology Organisation, or “ANSTO” and involves an acid-leach process of recovering low-grade lithium that was otherwise destined for the waste dump.
Lithium is typically extracted using an energy-hungry and expensive process known as roasting, which makes Lithium Australia’s low-cost method of extraction using chemicals instead of roasting somewhat unique and considerably more cost-effective.
The process has been extensively tested under pilot plant conditions at ANSTO’s facility in Lucas Heights, NSW.
According to ANSTO, the ability to extract lithium from “mica” minerals in particular, which are commonly rejected as waste as part of spodumene processing and other operations, may ultimately help improve the economics of lithium projects by increasing resource utilisation and reducing costs.
Importantly, the ability to produce lithium phosphate from these feeds using the SiLeach process allows Lithium Australia to manufacture cathode powders for lithium ferro phosphate, or “LFP” batteries using the technology of the company’s wholly owned subsidiary, VSPC.
Using the VSPC technology, lithium phosphate produced from pilot work at ANSTO has been converted into lithium ferro phosphate cathode powders that display exceptional performance in comparison to existing lithium ferro phosphate cathode materials, according to ANSTO.
Lithium Australia says, unlike other processes, the SiLeach flowsheet design contains specific fluorine removal and control steps in order to optimise the handling of fluorine generated during the decomposition of the mica minerals.
The company says SiLeach eliminates much of the requirement for evaporation, a high capital and operating cost burden of semi-competing systems. Direct precipitation of lithium as a phosphate, and its subsequent refining, provides the potential for direct feed into the production of LFP cathode powders.
Lithium Australia Managing Director, Adrian Griffin said: "Lithium Australia’s revolutionary SiLeach process unlocks the value in lithium-bearing clays and micas. The SiLeach process can produce a range of lithium chemicals, including lithium hydroxide, lithium carbonate and lithium phosphate. Significantly, the use of lithium phosphate is the shortest route to the production of lithium ferro phosphate (LFP) batteries.”
“Granting of the US SiLeach patent is timely, given increased interest in the extraction of lithium from clays in North America and even more so now that LFP is the most rapidly expanding sector of the lithium-ion battery industry. The lithium and phosphorus required to manufacture LFP are both produced by SiLeach as a single lithium chemical.”
According to Lithium Australia, supply of lithium phosphate to LFP producers eliminates the requirement for lithium hydroxide or lithium carbonate in some of the LFP production processes, thereby shortening the supply chain and removing a very costly step in the process.
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By Matt Birney
