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徐颖, 邓利蓉, 芦玉峰, 左联, 杜广报. 热处理对柯尔碱膨润土微观结构和物化性能的影响[J]. 岩矿测试, 2019, 38(3): 280-287. DOI: 10.15898/j.cnki.11-2131/td.201804190062
引用本文: 徐颖, 邓利蓉, 芦玉峰, 左联, 杜广报. 热处理对柯尔碱膨润土微观结构和物化性能的影响[J]. 岩矿测试, 2019, 38(3): 280-287. DOI: 10.15898/j.cnki.11-2131/td.201804190062
Ying XU, Li-rong DENG, Yu-feng LU, Lian ZUO, Guang-bao DU. Effect of Thermal Treatment on the Composition and Physicochemical Properties of Bentonite from the Kerjian Region, Xinjiang[J]. Rock and Mineral Analysis, 2019, 38(3): 280-287. DOI: 10.15898/j.cnki.11-2131/td.201804190062
Citation: Ying XU, Li-rong DENG, Yu-feng LU, Lian ZUO, Guang-bao DU. Effect of Thermal Treatment on the Composition and Physicochemical Properties of Bentonite from the Kerjian Region, Xinjiang[J]. Rock and Mineral Analysis, 2019, 38(3): 280-287. DOI: 10.15898/j.cnki.11-2131/td.201804190062

热处理对柯尔碱膨润土微观结构和物化性能的影响

Effect of Thermal Treatment on the Composition and Physicochemical Properties of Bentonite from the Kerjian Region, Xinjiang

  • 摘要: 膨润土的热稳定性及其热处理过程中微结构和性能的变化直接影响着膨润土在矿物材料领域的应用,因此研究热处理过程中膨润土成分结构的演化以及表面性质的变化具有重要意义。目前对膨润土的研究多集中在钠化改型、有机化改性以及改型改性后的结构和性能方面,而对膨润土热处理过程中的微观结构和物化性能变化研究有待加强。本文以新疆柯尔碱膨润土为研究对象,在不同温度下进行热处理,利用X射线荧光光谱法分析原土的化学成分,通过同步热分析、X射线衍射、红外光谱以及扫描电镜等技术对热处理产物进行了物相分析和结构表征,并研究了比表面积、吸蓝量及胶质价在升温过程中的变化特征。结果表明:随着热处理温度的升高,柯尔碱膨润土的比表面积逐渐减少,物相组成和结构都发生了很大变化。加热到600℃后,膨润土的吸蓝量和胶质价急剧下降,其主要成分蒙脱石八面体片中的羟基开始脱出,层状结构发生破坏;800℃后蒙脱石相已经消失;1000℃时产生新的矿相——堇青石,粉末颗粒出现熔融现象;1200℃后转变为方石英相,颗粒基本完全熔融,重结晶现象明显。研究认为,600℃时柯尔碱膨润土的膨胀性和分散性基本丧失,矿物物化性能失效。

     

    Abstract:
    BACKGROUNDThe thermal stability of bentonite and the changes of microstructure and property during heat treatment directly affect the application of bentonite in the field of mineral materials. Therefore, it is important to study the evolution of the composition and structure, and the change of surface properties of bentonite during heat treatment. Currently, the research of bentonite is concentrated in sodium modification, organic modification and retrofit of the modified structure and performance. The study of the changes in microstructure and physicochemical properties during the heat treatment of bentonite needs to be strengthened.
    OBJECTIVESTo investigate the microstructure and physicochemical property as a function of thermal treatment of bentonite from the Kerjian region in Xinjiang.
    METHODSBentonite from the Kerjian region in Xinjiang was heated at various temperatures. The chemical constituents of the original soil were analyzed by X-ray Fluorescence Spectrometry. The phase analysis and structural characterization of the heat-treated products were carried out by simultaneous thermal analysis, X-ray Diffraction, Infrared Spectroscopy and Scanning Electron Microscopy. The changes of specific surface area, methylene blue value and the gelling value during the heating process were studied.
    RESULTSWith the increase of heat treatment temperature, the specific surface area of Kerjian bentonite decreased gradually, and the phase composition and structure changed greatly. When heated to 600℃, the blue absorption and colloid value of bentonite decreased sharply, and the hydroxyl groups in the main component montmorillonite octahedron sheet began to break out, while the layered structure was damaged. The montmorillonite phase disappeared above 800℃. A new mineral phase cordierite was produced at 1000℃. Above 1200℃, the mineral was transformed into quartzite phase, the particles were completely melted, and the recrystallization was obvious.
    CONCLUSIONSIt is concluded that the expansibility and dispersion of Kerjian bentonite are basically lost at 600℃, and the mineral physicochemical properties are invalid.

     

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