安太堡11号煤层中锂镓分布赋存的差异性研究

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

为针对性分析煤层中锂、镓的分布赋存特征,选取安太堡11号煤层为研究对象,统计了锂、镓在各灰分级别、硫分级别及纵向分层中的分布特征。通过飞行时间二次离子质谱仪与带能谱的扫描电镜,分析了微区范围内锂、镓与常量元素的结合关系,讨论了煤层中锂、镓赋存状态差异性及影响因素。结果表明,锂富集于高灰煤中,镓在不同灰分级别与硫分级别煤中含量变化不显著。在纵向煤层中,锂在陆源物质供给充分时具有较高含量,镓分布较为均匀未呈现明显变化规律。微区原位分析中,锂的赋存与铝硅酸盐密切相关,镓可赋存于高岭石、勃姆石、黄铁矿、钠盐和钾盐中。煤层中锂与稳定元素锆的相关性系数为0.894,两者主要来源于物源区酸性岩浆岩。镓由于过渡元素的性质显示亲石性与亲硫性,在高灰煤与高硫煤中均具有较高含量,较强的元素迁移性使其在煤分层中趋于均匀分布。

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 highash 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.