铵伊利石的矿物学特征及热稳定性  

Mineralogical Characteristic and Thermostability of Ammonium Illite

作　　者：何妮 李尚颖 梁绍暹[3] 周轩平 武振晓 赵昊 汪洋 程宏飞 HE Ni;LI Shang-ying;LIANG Shao-xian;ZHOU Xuan-ping;WU Zhen-xiao;ZHAO Hao;WANG Yang;CHENG Hong-fei(School of Earth Science and Resources,Chang'an University,Xi'an 710054,Shaanxi,China;School of Land Engineering,Chang'an University,Xi'an 710054,Shaanxi,China;College of Geology and Environment,Xi'an University of Science and Technology,Xi'an 710054,Shaanxi,China)

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]长安大学土地工程学院,陕西西安710054 [3]西安科技大学地质与环境学院,陕西西安710054

出　　处：《地球科学与环境学报》2024年第2期229-239,共11页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(42172043,42302039,42202148);陕西省自然科学基金项目(2022JQ-291);中央高校基本科研业务费专项资金项目(300102263301,300102353102,300102273203)。

摘　　要：伊利石是地壳中常见的层状硅酸盐矿物。当NH_(4)^(+)赋存在伊利石层间时,可形成铵伊利石。探明铵伊利石的矿物学特征和层间NH_(4)^(+)的热稳定性可为理解氮(N)的地球化学循环提供重要依据。通过多种谱学、电子显微学和热分析手段,并以伊利石(层间阳离子为K^(+))为参照,对山西省阳泉市新景矿煤层夹矸中铵伊利石的矿物学特征和热稳定性进行研究。结果表明:铵伊利石中NH_(4)^(+)占层间阳离子总数的比例约为0.86,铵伊利石的基面间距(10.344)明显大于伊利石(9.973);同时,铵伊利石的(002)∶(003)衍射峰强度比值约为1∶1,而伊利石的相应衍射峰强度比值约为1∶3;铵伊利石四面体中广泛存在Al^(3+)对Si^(4+)的类质同象置换(Al^(3+)→Si^(4+)),其层电荷密度约为0.85;层间NH_(4)^(+)的存在未对伊利石的层状硅酸盐结构骨架造成明显影响,但可引起结构羟基蓝移;铵伊利石层间的NH_(4)^(+)表现出良好的热稳定性;在400℃~700℃温度范围内,NH+4随结构羟基的脱失而逐渐分解,这暗示在受热过程中层间NH_(4)^(+)与结构羟基发生反应,产物为NH_(3)和H_(2)O。Illite is a common layered silicate mineral in the Earth's crust.Ammonium illite can be formed when NH_(4)^(+) is located in the interlayers of illite.The identification of ammonium illite mineralogical characteristics and the thermostability of interlayered NH_(4)^(+) can provide an important basis for understanding the geochemical cycling of nitrogen.The mineralogical characteristics and thermal stability of ammonium illite collected from gangue in Xinjing coal mine of Yangquan city,Shanxi province,were comprehensively investigated with spectroscopic,electron microscopic,and thermal analyses,and using illite(its interlayered cation is K^(+))as a reference.The results show that the ratio of NH_(4)^(+) to total interlayer cations in ammonium illite is about 0.86,and the basal spacing(10.344)of ammonium illite is significantly larger than that(9.973)of illite;meanwhile,the intensity ratio of the(002)∶(003)diffraction peaks of ammonium illite is about 1∶1,whereas the corresponding ratio for illite is about 1∶3;in the tetrahedral sheets of ammonium illite,the isomorphous substitution of Al^(3+)for Si^(4+)(Al^(3+)→Si^(4+))widely exists,leading to a layer charge density of approximately 0.85;the presence of interlayered NH_(4)^(+) does not have a significant impact on the layered silicate framework of illite,but it can cause a blue shift in the structural hydroxyl groups;the interlayered NH_(4)^(+) of ammonium illite exhibits good thermostability;at temperatures ranging from 400℃ to 700℃,NH_(4)^(+) gradually decomposes with the loss of structural hydroxyl groups;this suggests that interlayered NH_(4)^(+) reacts with the structural hydroxyl groups during heating,resulting in the formation of NH_(3) and H_(2)O.These research results contribute to a deep understanding of the mineralogical characteristics and thermostability of ammonium illite.

关 键 词：铵伊利石 层间 矿物结构 谱学特征 热稳定性 载氮矿物 氮循环 

分 类 号：P575.4[天文地球—矿物学]