共沸蒸馏法制备电气石超细粉末

分别以水和正丁醇为研磨介质，得到电气石超细粉末的液相悬浮体，利用水和正丁醇可以形成共沸物的特点，分别采用直接加热和共沸蒸馏法脱分散介质干燥悬浮体制备电气石超细粉末。透射电镜分析结果表明，直接加热脱去水或正丁醇会使电气石超细颗粒发生硬团聚，而共沸蒸馏法则可有效防止硬团聚的产生；拉曼光谱结果表明，共沸蒸馏法制备的电气石粉末表面存在O—H和C—H键，说明正丁醇在颗粒表面为化学吸附，而直接干燥法得到的电气石粉末表面则没有；X射线粉晶衍射结果表明，研磨过程降低了粉末衍射峰的强度，但直接加热干燥和共沸蒸馏干燥均未破坏电气石的晶格结构。正丁醇中的丁氧基在共沸蒸馏过程中在电气石颗粒表面可取代羟基，产生化学吸附，能有效防止液桥的产生，阻止干燥过程中超细粉末的硬团聚。

The preparation of ultrafine tourmaline powder by azeotropic distillation method

The suspensions of ultrafine tourmaline powder in water and n_butanol were prepared by grinding. Ultrafine tourmaline powder was prepared by drying the suspensions through direct heating and azeotropic distillation, according to the properties that water may form azeotrope with n_butanol. TEM shows that drying by direct heating might result in hard aggregation of the tourmaline powder, while hard aggregation might be avoided by azeotropic distillation. Raman spectroscopy reveals that there are O_H and C_H on the surfaces of the tourmaline powder obtained by azeotropic distillation, which indicates that butoxy is chemically adsorbed on the surfaces of tourmaline particles, but not adsorbed on those formed by direct drying. X_ray powder diffraction shows that the intensity of diffraction peaks decreases after grinding. There is no damage to the tourmaline crystal lattice in the process of direct heating, azeotropic distillation, or ultrafine grinding. Therefore, butoxy in n_butanol can be adsorbed chemically on the surfaces of the tourmaline particles in the process of azeotropic distillation, which can effectively prevent the formation of liquid_bridge between the particles of tourmaline and avoid the hard aggregation in the drying process.