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.