High Purity Zirconia and Silica Powders via Wet Process: Alkali Fusion of Zircon Sand

Abstract

Zircon sand was reacted with liquid caustic soda (50% NaOH) in open vessel at 600 oC for 2h. The effect of NaOH/ZrSiO4 reactant ratio on the yield of zirconia recovery was verified. Samples of fusion products water washed were characterized by X-ray diffraction (XRD) to identify the main compounds formed. Silica powders were obtained via acid catalyzed reaction and zirconia powders were resulted from crystallization of zirconium oxychoride. Both zirconia and silica powders were analyzed by XRF (X-ray fluorescence) and BET method. Laser Quasi Elastic Light Scattering (QLS) technique was used for agglomerate size distribution determination. High purity and fine zirconia and silica powders were obtained. The specific surface area of zirconia calcined at 550 oC reached ~ 70m2g-1. Silica powder calcined at 800 oC presented a high specific surface area ~ 500 m2g-1.