Abstract:

As the demand for lithium increases, the extraction and processing of less economic sources of lithium such as lithium bearing clay minerals may become economically viable. Our study investigated the leaching of lithium from core samples taken from a brine well in Nevada, USA. Because clay minerals and lithium-rich brine can be co-located, our objective was to develop a leaching process that generates a lithium-rich liquor compatible with traditional lithium concentration and conversion technologies. Characterization of the core sample revealed ~ 51% framework silicates, ~ 30% clay minerals, ~ 12% calcite, and a lithium concentration of 690 ppm. An experimental leaching method using concentrated hydrochloric acid (HCl) combined with deionized water proved highly effective, producing a lithium-containing liquor suitable for concentration and conversion to lithium salts. We evaluated concentrated HCl-to-sample mass ratios ranging from 0.25:1 to 2:1. Neutralization precipitated Al, Fe, and Si, and subsequent filtration produced a clarified lithium-containing liquor. Lithium loss during neutralization was negligible for solvent-to-sample ratios up to 1:1. Overall, lithium extraction efficiencies ranged from 14% to 95%.

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Dr. Paul Craddock