Thermal, spectroscopic and X-ray diffractional analyses of zirconium hydroxides precipitated at low pH values

Differential thermal, thermogravimetric and elemental analyses in combination with infrared and Raman spectroscopies and X-ray diffraction (XRD) were used to follow the structural properties of zirconium hydroxides precipitated from zirconium oxychloride solution with aqueous ammonia at pH<7. The results show that the zirconium hydroxides have the composition and structure significantly different from the three types of the existing zirconium hydroxides, which were formed under alkaline conditions, and hence can behave much differently from those previously known. The DTA and TGA curves demonstrates that there is an abrupt weight drop for the former and hardly any weight loss for the latter in the region of the exothermic peak.