摘要
通过差热、热重、X射线衍射、透射电镜综合分析研究了凹凸棒石在热处理过程中脱水作用、结构、形貌变化之间的关系。结果表明在65℃,凹凸棒石开始脱去外表面吸附水,98℃脱去孔道水,凹凸棒石结构、形貌没有任何变化,微孔孔道直径未变。到230℃,部分脱去凹凸棒石的结晶水,由于脱出部分结晶水,凹凸棒石结构开始出现折叠。在481℃,脱去凹凸棒石的剩余结晶水。在595℃左右,缓慢脱去凹凸棒石的结构水,孔道结构完全塌陷,链层结构和形貌基本保持不变。高于800℃,凹凸棒石晶体开始变形弯曲,并变为无定形态。在827℃出现放热效应,形成方石英,这与1000℃出现严重烧结形貌特征一致。
The dehydration, structural and morphological properties of palygorskite during heat treatment were studied by thermogravimetric and differential thermal analysis, X-ray diffrction and high resolution transmission electron microscopy. The results indicate that water is absorbed in the channel and outside surface of the palygorskite samples, causing dehydration at 65℃ and 98℃, respectively; however, the structure and morphology of the samples are remained and unchanged. Some of the water in the samples is lost at 230℃, resulting in a structural fold in the structure of palygorskite. Residual water in the samples is lost at 481℃ and hydroxyls are lost at 595℃, degrading the channel structure, but the ribbon-like structure and morphology of palygorskite are retained. The morphology of palygorskite fibers is curved after heat treatment over 800℃, and the structure is transformed from a crystal structure to an amorphous structure. Then an exothermic reaction occurs at 827℃, and two new phases of cristobalite and enstatite are formed, which is similar to the sintering state at 1 000℃.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2006年第11期1406-1410,共5页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金(40472026)资助项目。
关键词
凹凸棒石
热处理
透射电镜
表面改性
晶体结构
palygorskite
heat treatment
high resolution transmission electron microscope
surface improvement
crystal structure
