EVALUATING HIGH-TEMPERATURE CORROSION OF SiC REFRACTORIES BY COAL SLAG USING IMPROVED EXPERIMENTAL METHOD

摘要

SiC refractories are currently utilized as lining materials for water-cooled gasifier at a service temperature lower than 1300oC. Very few researches have been reported on the corrosion of SiC materials at even higher temperature. In this paper, corrosion behavior of SSiC and Si3N4-SiC refractories interacted with coal slag was investigated at 1500°C under reducing atmosphere using improved rotary slag testing method. Moreover, interactions between refractory materials and molten slag were also predicted by thermodynamic calculations using modified model under the same conditions. The results showed that SSiC and Si3N4-SiC refractories presented the similar stability and corrosion behavior under simulated gasification conditions. SiC reacted with FeO to form Si-Fe-C alloy on the surface of the corroded materials. Meanwhile, SiO_2 phase was also formed by oxidation of SiC in the experimental atmosphere and then dissolved into the molten slag eventually.