The chemistry of zirconium sulphates and polyphosphates

Abstract

This thesis compnses a combination of fundamental and applied research on aspects of zirconium and phosphate chemistry of importance to the industry, covering the structure and chemistry of zirconium sulphates, the dehydration of phosphates and the hydrolysis of polyphosphates. The initial purpose was the development of zirconium phosphate-based flame-retardants and catalysts. However, during the course of the investigation it was discovered that important aspects of zirconium and phosphate chemistry that were required for the investigation were not available in the literature. These gaps in the basic understanding and use of this chemistry had to be filled in order to fully exploit the potential of zirconium phosphate compounds as flameretardants and catalysts, especially on an industrial scale. Of particular importance is the dissolution of zirconium raw materials for purification, which is essential to obtain a zirconium product suitable for catalytic purposes. It is, of course, well known that these materials are highly insoluble in water, and methods were investigated whereby they could be treated. The use of sulphates was one such method, which, in the author's opinion, is potentially one of the most successful ones for this purpose. The chemistry and structures of zirconium sulphates are therefore an important part of the investigation.