1. The glass contains nickel sulfide crystals. There is a phase transition process of NiS(nickel sulfide) at 379℃. If these impurities are in the tensile stress zone of the tempered glass, the volume expansion may cause the spontaneous burst of the tempered glass.



2. In order to eliminate the adverse effect of nickel sulfide on tempered glass, after the glass is tempered in the tempered furnace, homogenizing furnace should be used to homogenize the tempered glass. Homogenizing furnace is to heat the tempered glass to nickel sulfide phase transition temperature, and appropriate insulation, in order to promote nickel sulfide rapid phase transition, there may be a self-explosion of the tempered glass detonated in advance, so as to avoid the future nickel sulfide caused by the tempered glass self-explosion, improve the yield of tempered glass;