Aim-listed CleanTech Lithium and technology partner Empower EIT have successfully produced high-purity lithium carbonate from eluate produced by CleanTech's direct lithium extraction (DLE) pilot plant in Chile.

About 330 kg of high-purity lithium carbonate has been produced with grades between 99.68% and 99.91%, with the downstream processing having been undertaken by US-based vertically integrated lithium producer Empower.

CleanTech says further key testwork is under way to optimise and verify the process used in the Laguna Verde prefeasibility study (PFS).

CleanTech has asked leading lithium brine services company Zelandez to conduct a comprehensive spent brine reinjection options analysis to support the sustainable development of Laguna Verde.

Meanwhile, in delivering CleanTech's first batch of high-purity lithium carbonate, Empower processed about 55 000 litres of eluate at its advanced lithium processing facility in Dallas. The eluate was produced from Laguna Verde brine at CleanTech's DLE pilot plant, in Chile.

CleanTech partnered with Empower for the downstream processing of eluate produced at the DLE plant to demonstrate a process that can consistently produce lithium carbonate product from CleanTech's feedstock.

CleanTech says the nanofiltration stage of the endeavour used the latest DuPont FilmTec LiNE-XD Element high productivity nanofiltration membranes for lithium brine purification to achieve superior purification and efficiency.

NEXT STEPS

CleanTech is currently undertaking a PFS process validation trial in Chile, advanced definitive feasibility study- (DFS-) level adsorbent testwork in France and a spent brine reinjection option study.

The company is undertaking a pilot programme with Xian Lanshen New Material Company to optimise and verify the process used in the PFS for the Laguna Verde project.  A volume of 20 m³ of feed brine from Laguna Verde is being processed at Lanshen´s pilot plant facility in Santiago, Chile.

Reports have been received on the first stage to verify DLE process parameters, and the second stage of evaluating advanced membrane and purification process steps. The final stage is carbonation to lithium carbonate to meet rigorous Chinese battery grade standards, including production of a 5 kg sample of lithium carbonate.

When the final stage is completed and the lithium carbonate sample has been tested by an external laboratory, the results will be reported to the market.

The absorbent testwork, meanwhile, will involve a trial starting in the coming weeks together with French consulting firm Hephaistos Insights, which will conduct DLE benchmarking and eluate analysis using brine from Laguna Verde.

The programme will assess a range of adsorbent options against the project's specific brine chemistry, with a particular focus on elution efficiency. The bench-scale testing, which will be executed by specialist subcontractor Seprosys, will include CleanTech's current reference adsorbent alongside alternatives from North American and European suppliers.

This workstream is designed to confirm the optimal adsorbent selection for Laguna Verde ahead of the DFS.

In this regard, Zelandez will deploy a multidisciplinary team of hydrogeologists, reservoir engineers and DLE experts to evaluate aquifer reinjection concepts, which will culminate in a technical analysis that integrates vital basin-dynamics, environmental permitting screens and cost modelling to deliver a recommended DFS workplan than can advance sustainable development of Laguna Verde.