Corrosion of Alkali Metals on SiC-Si3N4 Refractory of Pusher Kiln

When using pusher kiln to produce vanadium nitrogen alloy, alkali metalsAlkali metals in raw materials will volatilize and deposit in the kiln, which will corrode refractoriesRefractories and hinder the smooth production. Therefore, it is of great significance to study the corrosionCorrosion of refractory by sediment. In this paper, SiC-Si3N4 composite brick was used as the research object, and sodium carbonate and potassium carbonate were used as corrosionCorrosion reagents to carry out corrosionCorrosion experiments in a vacuum tube furnaceFurnace. The results indicate that the surface of the composite brick occurs microporous and spalling phenomenon after being corroded by sodium carbonate or potassium carbonate for 3 h. The thicknesses of spalling layer and corrosion layer caused by sodium carbonate are 3.0 mm and 2.67 mm, respectively. The thicknesses of spalling layer and corrosionCorrosion layer caused by potassium carbonate are 0.5 mm and 0.77 mm, respectively. It was found that the corrosion ability of sodium carbonate to SiC-Si3N4 composite brick is stronger than that of potassium carbonate. Combined with theoretical calculation and experimental characterization, it is found that the corrosionCorrosion processProcess is divided into three stages: corrosion reaction, slagging, and reduction of alkali metalAlkali metals oxides.