Thermal Decomposition Process of Zirconium Oxide Chloride Octahydrate

Abstract

Thermal decomposition process of zirconium oxide chloride octahydrate (ZrOCl₂ 8H₂0) was investigated by changing the heating rate. Thermal equilibrium between sample and atmosphere was nearly achieved at the heating rate of 15°C/hr. On the basis of stoichiometric considerations of TG curves and its differential curves, chemical analysis of the decomposition products, and analyses of infra-red spectra and X-ray diffraction patterns, following stepwise thermal decomposition is proposed; (1) ZrOCl2 H₂O is dehydrated to produce ZrOCl2.4 H₂O, (2) dechlorination of ZrOCl2.3 H₂0 or ZrOCl2 H₂O proceeds and hydrated zirconium oxids comes out, (3) monoclinic zirconium oxide results above 850°C. In the thermal decomposition zirconium is not removed from the system.