Differences in the distribution and occurrence of lithium and gallium in the No.11 coal seam from the Antaibao mining district

In order to analyze the distribution and occurrence of lithium (Li) and gallium (Ga) in coal separately, the No.11 coal seam from the Antaibao mining district was collected as research object. The distribution of Li and Ga in different ash fractions, sulfur fractions, and coal column benches was discussed. The relationship between Li and Ga with other major elements in the micro-area was investigated by time-of-flight secondary ion mass spectrometer (TOF-SIMS) and scanning electron microscope with energy dispersive spectrometer (SEM-EDS). The difference in the occurrence of Li and Ga, and the influencing factors were discussed. The results show that Li is enriched in high-ash coal, while Ga does not change significantly in coal samples in various ash and sulfur fractions. In the longitudinal seam, Li is enriched in the coal bench with sufficient supply of terrestrial source material, while Ga is more evenly distributed in the coal seam. In the in-situ regions, Li occurs only in aluminosilicates, while Ga can occur in kaolinite, boehmite, pyrite, chloride, and sylvite. The correlation coefficient between Li and stable element zirconium (Zr) for all samples is 0.894. Both are mainly derived from acidic magmatic rocks in the source area. Gallium is abundant in both high ash coal and high sulfur coal due to its transitional property as a lithophile and sulphophile element. Its mobility makes it tend to be uniformly distributed in the coal seam.