Influence of raw material purity on microstructure and properties of calcia refractory

Calcia refractory exhibits considerable potential owing to its capacity to purify melts. This work analyzes different purity calcia for their microstructure, crystal size distribution, and bonding phases. The pilot-scale calcia crucibles were prepared from two calcia refractories of different purity using cold isostatic pressing. The findings show that calcia refractory purity affects the properties of calcia crucibles. Fewer Ca3Al2O6 and Ca3SiO5 results in well-developed calcia grains and improved hydration resistance. The high-purity calcia crucible has better high-temperature strength and thermal shock resistance than the low-purity one. The high-purity crucible possesses a low strength reduction of 69% after thermal shock and a high hot modulus of rupture of 4.2 MPa at 1400 celcius. In contrast, the low-purity crucible displays inferior properties, with strength loss reaching 80% and a hot modulus of rupture measuring 0.73 MPa. Therefore, high-purity calcia is considered a potential refractory for manufacturing oxide crucibles.