CUI Xiao-nan1,2,3, HUANG Wen-hui1,2,3, AO Wei-hua4, HU Zha-zha1,2,3
(1. School of Energy Resources, China University of Geosciences (Beijing), Beijing 100083, China;
2. Key Laboratory for Marine Reservoir Evolution and Hydrocarbon Abundance Mechanism (Ministry of Education), China University of Geosciences (Beijing), Beijing 100083, China;
3. Beijing Key Laboratory of Unconventional Natural Gas Geology Evaluation and Development Engineering, China University of Geosciences (Beijing), Beijing 100083, China;
4. School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083, China)
Abstract: Mineral composition and micromorphology of minerals in the weathered residual kaolin deposit from Zhangzhou Area, China were studied using chemical composition analysis, X-ray diffraction (XRD), Infrared spectroscopy (IR), thermogravimetry-differential scanning calorimetry (TGA-DSC) and scanning electron Microscope (SEM). Although the mineral composition only consists of kaolinite, quartz and minor potassium feldspar, the quartz content is relatively high. As a result, chemical composition of the sample presents the feature of high silicon and low aluminum, and the molar ration of SiO2/Al2O3 is approximately 4. The sample has a low content of K, Ca, and Mg, but high contents of Fe and Ti, while the content of K varies in a wide range. The kaolin deposit is not fully weathered and the kaolinite presents a poor crystallinity, which can be evidenced by the dispersive and asymmetric XRD reflections of the sample. The SEM images for the samples do not show regular hexagonal plate which is a symbol of well-ordered kaolinite, but irregular and crumby morphology. Additionally, the samples show a low thermal stability with dehydroxylation below 500 ℃, further demonstrating the poor crystallinity of the kaolinite.
Keywords: kaolin; weathered residual type; mineral composition; chemical composition; crystallinity
E-mail: huangwh@cugb.edu.cn
ACTA MINERALOGICA SINICA Vol. 36, No. 3, 2016, Page 377-381
