论文部分内容阅读
综合多种测试方法,考察了研磨对茂名高岭石粒径、形貌与微结构等理化性质的影响。重点采用~(29)Si、~(27)Al MAS NMR光谱考察了研磨过程中结构脱羟、Si、Al配位环境变化、新活性位点形成等微结构演变等。结果表明:研磨初期,高岭石六方片层遭到破碎,颗粒粒径逐渐减小,比表面积在研磨1 h达到最大(43.8 m~2/g);此后,颗粒发生团聚,比表面积减小,样品脱羟量和表面吸附水含量均逐渐增加。核磁Si谱和Al谱分别在化学位移-100.5和14.8处出现新的信号,归属于四面体Si与八面体Al相连顶氧质子化作用而产生的Q_3 Si-OH~+-Al结构。研磨导致高岭石脱羟,Al配位状态从Al~Ⅵ经由Al~Ⅴ逐渐向Al~Ⅳ转变。
Based on a variety of testing methods, the effects of grinding on physical and chemical properties such as particle size, morphology and microstructure of kaolin were investigated. The structural dehydroxylation, the coordination of Si and Al, the microstructure evolution of new active sites, etc, were investigated by ~ (29) Si and ~ (27) Al MAS NMR spectra. The results showed that the hexagonal kaolinite fragments were crushed and the particle size decreased gradually during the initial grinding. The specific surface area reached the maximum (43.8 m 2 / g) after grinding for 1 h, and then the particles aggregated and the specific surface area decreased , The amount of sample dehydroxylation and the surface adsorption of water content are gradually increased. The new signals appeared at the chemical shifts of -100.5 and 14.8, respectively, belonging to the Q_3 Si-OH ~ + -Al structure resulting from the protonation of tetrahedral Si with the octahedron Al. Milling led to the kaolinite dehydroxylation, and the Al coordination state gradually changed from Al to VI via Al ~ V to Al ~ Ⅳ.