Mineralogical Composition and Occurrence State of Lithium in Lithium-Enriched Claystone in the Zhenba Area, Southern Shaanxi, by X-Ray Diffraction and TIMA Analysis

The newly discovered clay-type lithium ore (resources) in the upper Permian Wujiaping Formation in the Zhenba area of Shanxi Province has a maximum Li₂O content of 0.39%, which reaches the industrial index of clay lithium ore (0.2%), and has certain development and utilization values. To determine the mineral’s composition of lithium-enriched claystone and the occurrence state of lithium, a microscope was used to preliminarily observe the mineral composition, X-ray diffraction (XRD) and TIMA (TESCAN Integrated Mineral Analyzer) were used to analyze clay minerals and the main elemental content. The lithium-enriched claystone in the Zhenba area is mainly composed of kaolinite, sudoite, illite, cookeite and hematite, containing a small amount of chlorite, rutile and other minerals. TIMA analysis shows that the highest content of cookeite is 8.94%, and the highest Li content is 0.12% (Li₂O content is 0.26%), which is slightly lower than the whole rock Li₂O value (0.31%). The cookeite is silky and irregularly granular, and is dispersed between boehmite, illite and sudoite. The results show that lithium in claystone occurs mainly in cookeite, and other clay minerals have low lithium content.