CleanTech Lithium PLC (CTL) has produced a high purity lithium carbonate sample from the company´s pilot plant downstream process.
CleanTech is processing concentrated eluate from its direct lithium extraction (DLE) pilot plant in Copiapó, Chile at the facilities of Conductive Energy in Chicago, USA, with the aim of producing battery grade lithium carbonate.
The downstream process design aims to minimise process steps and to demonstrate a process that is scalable and can consistently produce a battery-grade lithium carbonate product.
The process consists of: eluate concentration using forward osmosis (“iFO”) to produce a highly concentrated pre-carbonation solution with low energy input, treatment of the pre-carbonation solution to remove contaminants, carbonation to technical-grade lithium carbonate, and post-carbonation polishing to achieve battery-grade lithium carbonate.
A substantial volume of pre-carbonation solution and lithium carbonate was produced towards the end of last year.
Due to the onset of freezing weather in Chicago from late November, steps were taken to mitigate damage to sensitive iFO processing equipment and iFO concentration was paused.
Further downstream processing continued using the already produced pre-carbonation solution to refine and analyse the downstream process and lithium carbonate product.
In December, a test run volume of pre-carbonation solution was processed into an 8kg sample of high grade lithium carbonate. A laboratory at the University of Calgary has recently confirmed that this sample achieved 99.78% purity.
This exceeds the 99.6% purity standard (Chinese GB/T 23853-2022 (Type 1) for battery grade lithium carbonate from brine.
The treatment process was shown to be effective at removing contaminants, resulting in high-quality feed to the carbonation stage.
The most problematic contaminants in the pre-carbonation solution, calcium, magnesium and boron, were reduced by 98.5%, 99.9% and to non-detection (>99.99%) respectively.
Conductive Energy is currently assessing best options to restart iFO operations that are paused due to winter conditions.
Conductive is utilising the current pause to upgrade the system based on initial data as well as to add an nanofiltration step which will improve purification efficiency further whilst improvements in automation and process control will be made.
Separately, CleanTech is to voluntarily delist from the OTCQX market in the U.S. The company's shares continue to trade on the London Aim Market, the Frankfurt Stock Exchange and the U.S. OTC Pink Market.
“We are pleased to report the production of high grade lithium carbonate with a purity of 99.78% from an initial batch of concentrated eluate from our Laguna Verde project,” said Steve Kesler, executive chairman of CleanTech Lithium.
“This phase of work has focused on fine-tuning the process and preparing to scale up pilot plant output. Our collaborative efforts with Conductive Energy and Forward Water on the downstream process are advancing our aim to produce significant quantities of battery grade product to introduce to potential strategic partners and off-takers."
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Some have been sceptical that DLE was ever going to work, but CleanTech have been ticking the boxes systematically and one-by-one. Reaching the purity threshold is highly significant, and demonstrates that the company has got a hand on every stage of production, from extraction to the final stages of processing.