Thermal-Vacuum Method for Obtaining Nanodispersed Zirconium Dioxide

Abstract

An energy-efficient thermal-vacuum method for continuous production of nanodispersed powder of amorphous zirconium dioxide from zirconium hydroxide has been developed. This approach is based on a principle of creating an aerodynamic flow with an initial powder-like material in the cavity of the heating element of a thermal-vacuum installation. In this way, short-term contacts of particles of zirconium hydroxide with the inner surface of the heating element made in the form of the winding helical are created. As a result, the crushing of the particles is carried out due to the high thermal stresses in the particles contacted. This process is aggravated by the presence of residual moisture in the original powdery material. Transformations of the zirconium hydroxide in the process of thermal-vacuum treatment have been investigated. Amorphous dioxide has been obtained. The study of structural composition of the material in the initial state and processed in a thermal-vacuum installation was carried out using X-ray analysis and scanning microscopy. Experimental data on the structural-phase composition of the original material and data on the closest structural prototypes of crystalline-impurity compounds are presented. They are also given data on the volume of crystal cells and estimates of the molar concentration of the components. A mass spectrometric assessment of the elemental composition of the obtained zirconium dioxide is given. Thermal-vacuum method allows toobtain highly dispersed zirconium dioxide in its amorphous state directly from zirconium hydroxide without using liquid media and, moreover, in a short time – within 15...20 s.