Dissolution and precipitation behaviors of zircon under the atmospheric environment

Abstract

The reactive behavior of zircon in three different solutions: 0.1 M HCl (aq), ultrapure water, and 0.1 M NaOH (aq) was examined under normal temperature and pressure conditions. Dissolved Si and Zr concentrations show that considerable Zr precipitated on the surface in all immersion cases. Bulk changes in the zircon were insignificant. However, the obvious surface change of the zircon immersed in 0.1 M NaOH (aq) was confirmed. Porous layer comprising an amorphous SiOx phase and needle crystals of ZrSiO4 around pores were detected on the near-surface area of the zircon immersed in 0.1 M NaOH (aq). Consequently, the reaction was limited when zircon was immersed in ultrapure water. Zr precipitated on the surface after the dissolution of ZrSiO4 in 0.1 M HCl (aq). Dissolved Zr and Si in 0.1 M NaOH (aq) precipitated on the surface, then the dissolution of ZrSiO4 formed a porous layer, and most dissolved Zr precipitated as zircon crystals.