Neometals says its pilot-stage ELiTM electrolytic” process to produce lithium hydroxide from lithium chloride in brine has successfully produced high purity lithium hydroxide monohydrate crystals. The pilot trial involved 1000 hours of exposure of South American lithium chloride brines to Neometals’ electrolytic process and confirmed the expected power consumption, membrane life and scaleability of the commercial application.
The ELiTM process offers a significant alternative to the currently more typical lithium hydroxide production process.
It achieves this mainly by eliminating the usual requirement for the dual steps of introducing bulk sodium carbonate and calcium hydroxide required for the chemical precipitation of sodium chloride and calcium carbonate, prior to final lithium hydroxide production.
The ELiTM process – which is owned 70 per cent by Neometals and 30 percent by mega-miner Mineral Resources - incorporates an initial nano-filtration step prior to purification, followed by electrolysis.
The nano-filtration takes care of a significant chunk of the purification/precipitation time and required horsepower and it also cleans up the feed solution for the electrolytic cell to eliminate deleterious solids and unwanted electrolytes from the circuit.
Min Res and Neometals have commissioned a JV vehicle, Reed Advanced Materials to progress the technology. Reed subjected the electrolytic membrane to a 1,000-hour durability test, employing a lithium chloride solution which it obtained during a previous ‘purification’ trial on lithium-pregnant brine sourced from South America.
The electrolytic cell membrane test was run over a period five times longer than previous tests and the results support current estimates of the two most significant variable operating costs for similar processes, which essentially boil down to power consumption and membrane life.
The trial was satisfactorily finalised with production of lithium hydroxide monohydrate (LiOH.H2O - or “LHM”) of very high purity at the cathode.
This was processed in the crystallisation trial to produce a final LHM product with sample splits being sent for analysis in separate laboratories in South Africa and Australia.
The current efficiency for the trial averaged about 74 per cent and trended upwards during the course of testing, which is in keeping with historical electrolysis results on synthetic brine solutions.
The efficiency measures actual product at the cathode as a percentage of the maximum possible production and results support the electricity consumption assumed in the company’s 2023 engineering cost study.
Membrane examination showed it to remain in good condition with no significant build-up of deleterious elements identified in the destructive digestion test of the membrane. This benefit could be at least partly due to the up-front nano-filtration.
A shorter 40-hour duration test examined the flow performance and polarisation characteristics of a full-height commercial electrolytic cell, which confirmed the same flowsheet can be applied to commercial-scale electrolysis.
The company views the results as significant because they confirm or exceed previous third party results from processing of synthetic brine solutions using commercial lithium chloride crystals.
The outcome offers confidence in the electrolytic route to converting lithium chloride brines to lithium hydroxide, with the key benefit of the ELiTM process lying in the notable reduction of major operating costs.
The ELiTM process constitutes a major breakthrough in the commercialisation of the relatively straight-forward, low-capex, low-risk electrolytic technology.
Reed holds 19 granted patents for the process in the principal lithium-producing parts of the world and has a further 14 pending national patents at various stages of application globally.
The ELiTM pilot trial has satisfied the set objectives and demonstrated the readiness of the electrolytic technology for up-scaling.
Reed has now prepared an information memorandum and established a data room to kick off a formal process of industrial partner selection, with the goal of advancing the technology through industrial validation in plant demonstration trials.
It continues to evaluate other third-party brine samples and the company is also advancing discussions with chlor-alkali plant manufacturers.
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By Doug Bright
