Study on the leaching of lithium from lithium-poor clay-type ore using tartaric acid by calcination and water leaching

This study focuses on the ore characteristics and occurrence status of lithium in lithium-poor clay-type ores by employing activation pretreatment by calcination followed by leaching with tartaric acid. This study investigates the influence of factors such as calcination temperature, calcination time, and leaching temperature on the leaching yield of Li. The findings show the optimal leaching conditions for Li extraction as follows: calcination temperature, 600 °C; calcination time, 5 min; leaching temperature, 100 °C; ore-tartaric acid mass ratio, 5:7; leaching time, 5 h; and ore-water ratio, 1:3 (g/mL), resulting in a leaching yield of Li of 85.0%. According to the results of the three-cycle leaching experiments, the Li concentration in the leach liquor increased from 40.2 mg/L to 125 mg/L, indicating efficient utilization of tartaric acid and successful Li enrichment. Moreover, the XRD, SEM, TG-DSC, and FTIR analyses of the samples reveal that tartaric acid dissociates into C₄H₅O₆⁻ and C₄H₄O₆²⁻, which then form complexes with ions such as Li⁺, Al³⁺, Ca²⁺, and Fe³⁺ that are dissolved during the ore leaching process. With an increase in leaching time, complexes involving Al, Ca, Fe, and tartaric acid radicals result in precipitation, leading to a reduction in the content of these ions in the leach liquor. This increases the selectivity of Li extraction, which is beneficial for the subsequent separation and extraction of Li.