The company stated that process work has already demonstrated that the claystones at the TLC project, which is located close to the historic Tonopah mining area, are amenable to rapid lithium extraction using warm sulphuric acid leaching. Using this method at 80°C, the claystones reach 92% lithium extraction in approximately 10 minutes.
Furthermore, salt roasting followed by water leaching has generated up to 82% lithium extraction. The metallurgical consulting company TECMMINE ran test work at its facility in Lima, Peru, using hydrochloric acid at a temperature of 90°C for one hour, which achieved 95.1% lithium extraction.
American Lithium noted that similar to sulphuric acid leaching, hydrochloric acid leaching has impurities in the resulting solution. The impurities need to be removed, but there is still an advantage to the higher lithium extraction.
Another benefit of leaching with hydrochloric acid is that acid can potentially be rejuvenated through pyrolysis and reused. Ultimately, in the future this could reduce reagent use and the associated operating costs of a potential lithium production operation at TLC.
American Lithium stated that the multiple process options for TLC, along the ability to pre-concentrate and upgrade, make the project flexible and position it well.
The company's continuing process work will focus on optimising all the processing options and flowsheet designs to facilitate a robust preliminary economic assessment (PEA). It will continue optimisation work into the autumn using the three possible processing options - hydrochloric acid leaching, sulphuric acid leaching and salt roasting followed by water leaching. The company said it is committed to producing an environmentally sound process to supply lithium products that are cost competitive.
Dr Laurence Stefan, COO of American Lithium, said: "American Lithium continues to explore all relevant processing options. These new results not only demonstrate the highest lithium extraction achieved to date, but further indicates that a variety of lithium extraction options are available to us for our TLC claystones and positions us well to deliver a robust PEA late this year / early next year. All three processes offer us the ability to produce lithium carbonate. We will focus on optimising the best approach from an economic and environmental perspective."
