Palygorskite clays sampled from palygorskite clay deposits in Jiangsu and Anhui provinces were investigated by transmission electron microscopy (TEM). Many intergrowth phenomena of special ultra-microstructure between...Palygorskite clays sampled from palygorskite clay deposits in Jiangsu and Anhui provinces were investigated by transmission electron microscopy (TEM). Many intergrowth phenomena of special ultra-microstructure between smectite and palygorskite were found. The ultra-microstructure indicates that palygorsite fiberrous crystals grow along (001) of primary smectite through structural transformation and decomposition of the primary smectite. According to field investigation and X-ray diffraction (XRD) analyses, the transformation mechanism and process can be described as: formation of smectite from basalt weathering deposited in localiza- tion basin; evaporation of lake water in aridity environment causing pH increase and concentra- tion of magnesium ion in interstice water of sediment smectite in the lake basin. Under alkaline conditions, magnesium ion occupied interlayer positions of the smectite. Because of the misfit between magnesium octahedral sheet and smectite layer, magnesium ion interaction with smec- tite layers caused the smectite to transform into palygorskite, and resulted in the formation of smectite and palygorskite complex particulates, and even smaller secondary smectite crystal plates. The transformation of smectite structure resulted in the formation of nanometer minerals with large specific surface area and excellent property of physics and chemistry in smec- tite-palygorskite mixing clay. The results from TEM investigation are important for understanding properties of palygorskite clay and application.展开更多
利用X′Pert PRO X-射线衍射分析仪、XL-30能谱分析等岩矿测试手段,系统评价了蒙脱石在5%HCl、5%HCl＋0.5%HF、5%HCl＋1.0%HF、0.5%HF、1.0%HF、8%HBF4、5%HCl＋7%HBF4七种常见酸体系中的化学行为,重点分析了酸液中硅、铝元素离子浓度...利用X′Pert PRO X-射线衍射分析仪、XL-30能谱分析等岩矿测试手段,系统评价了蒙脱石在5%HCl、5%HCl＋0.5%HF、5%HCl＋1.0%HF、0.5%HF、1.0%HF、8%HBF4、5%HCl＋7%HBF4七种常见酸体系中的化学行为,重点分析了酸液中硅、铝元素离子浓度、酸蚀量、晶体结构稳定性等参数随时间、酸浓度、酸类型间变化规律。研究指出,土酸、HF、氟硼酸体系与蒙脱石反应均表现出强酸的性质特点,但是氟硼酸体系离子浓度达到最大值迟土酸0.5~1.0h;与晶体结构中的Si/Al重量理论值对比,发现酸对蒙脱石晶体中的铝氧八面体破坏性强于硅氧四面体。7%HBF4和5%HCl＋7%HBF4两体系与蒙脱石反应2h后d（001）晶面破坏,并出现新峰;而相对应的土酸体系中蒙脱石固相反而比较稳定,因此不难判断B-、F-等有利于促使蒙脱石向其它矿物转化。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.40072017).
文摘Palygorskite clays sampled from palygorskite clay deposits in Jiangsu and Anhui provinces were investigated by transmission electron microscopy (TEM). Many intergrowth phenomena of special ultra-microstructure between smectite and palygorskite were found. The ultra-microstructure indicates that palygorsite fiberrous crystals grow along (001) of primary smectite through structural transformation and decomposition of the primary smectite. According to field investigation and X-ray diffraction (XRD) analyses, the transformation mechanism and process can be described as: formation of smectite from basalt weathering deposited in localiza- tion basin; evaporation of lake water in aridity environment causing pH increase and concentra- tion of magnesium ion in interstice water of sediment smectite in the lake basin. Under alkaline conditions, magnesium ion occupied interlayer positions of the smectite. Because of the misfit between magnesium octahedral sheet and smectite layer, magnesium ion interaction with smec- tite layers caused the smectite to transform into palygorskite, and resulted in the formation of smectite and palygorskite complex particulates, and even smaller secondary smectite crystal plates. The transformation of smectite structure resulted in the formation of nanometer minerals with large specific surface area and excellent property of physics and chemistry in smec- tite-palygorskite mixing clay. The results from TEM investigation are important for understanding properties of palygorskite clay and application.
文摘利用X′Pert PRO X-射线衍射分析仪、XL-30能谱分析等岩矿测试手段,系统评价了蒙脱石在5%HCl、5%HCl＋0.5%HF、5%HCl＋1.0%HF、0.5%HF、1.0%HF、8%HBF4、5%HCl＋7%HBF4七种常见酸体系中的化学行为,重点分析了酸液中硅、铝元素离子浓度、酸蚀量、晶体结构稳定性等参数随时间、酸浓度、酸类型间变化规律。研究指出,土酸、HF、氟硼酸体系与蒙脱石反应均表现出强酸的性质特点,但是氟硼酸体系离子浓度达到最大值迟土酸0.5~1.0h;与晶体结构中的Si/Al重量理论值对比,发现酸对蒙脱石晶体中的铝氧八面体破坏性强于硅氧四面体。7%HBF4和5%HCl＋7%HBF4两体系与蒙脱石反应2h后d（001）晶面破坏,并出现新峰;而相对应的土酸体系中蒙脱石固相反而比较稳定,因此不难判断B-、F-等有利于促使蒙脱石向其它矿物转化。
