Effects of Various Oxides on Sintering of Zircon at 1500°C

Abstract

Twenty-eight kinds of oxides, in amounts up to five weight per cent, were added into zircon in orderto investigate their effects on decrement of apparent porosity and dissociation of zircon refractoriesduring sintering at 1 500°C
Na₂O, K₂O, MgO, CaO, ZnO, B₂O₃, MnO₂, Fe₂O₃, Co₂O₃, and NiO promoted markedly sinteringof zircon. Cu₂O, CuO, BeO, CeO₂, TiO₂, P₂O₅, SrO, and BaO did slightly, but ThO₂, Al₂O₃, SnO, Pb₂O, PbO, V₂O₅, SeO₂, Cr₂O₃, MoO₃ and WO₃ did not.
Among the oxides that promoted sintering of zircon, Cu₂O, CuO, BeO, CeO₂, TiO₂, P₂O₅ Fe₂O₃, NiO, ZnO MnO₂ and Co₂O₃ had almost no effect on the dissociation of zircon at 1500°C.
When specimens contained these oxides were kept for two hours at 1600°C. The dissociation of zirconwas not affected by addition of BeO, ZnO, Fe₂O₃ nor NiO, whereas it was affected a little byaddition of Cu₂O or CO₂O₃, and markedly by addition of TiO₂.
The result of slagging test for specimens containing Fe₂O₃, ZnO, or Co₂O₃ was satisfied but that forCu₂O, or NiO was unsatisfied.
Conclusively, zircon refractories containing a little amount of Fe₂O₃, ZnO, or Co₂O₃ had lowerapparent porosity without little dissociation of zircon at 1500°C and had better result for slagging test.