Fire resistance refers to the ability of kaolin to resist high temperatures without melting. The temperature at which softening occurs and melting begins under high-temperature operation is called the refractory degree. It can be directly measured using standard temperature measuring cones or high-temperature microscopes, or calculated using the M.A. Bezbeldorf empirical formula. Fire resistance t (℃)=[360+Al2O3-R2O]/0.228 In the formula, Al2O3 is the mass percentage of Al2O3 when the sum of SiO2 and Al2O3 analysis results is 100; R2O is the mass percentage of other oxides when the sum of SiO2 and Al2O3 analysis results is 100. The error in calculating the fire resistance through this formula is within 50 ℃
