Precautions for baking in glass kilns built with AZS fused bricks

Precautions for baking in glass kilns built with AZS fused bricks

When using AZS fused bricks to build the glass kiln arch, the following matters should be noted during ignition and baking:

(1) Cold inspection before ignition includes inspection of gaps in the wall, openings, bottom, expansion joints, steel structure and other parts related to kiln heating; for tank furnaces with AZS bricks as arches, special attention should be paid to the inspection of steel structure, including whether the position of the top rod is reasonable, whether the top rod nut is welded firmly, whether the tie rod nut and thread are lubricated, and whether the iron parts related to masonry expansion hinder the expansion of the masonry. In addition, attention should be paid to protecting the iron parts exposed near the expansion joints to prevent burning during kiln baking.

(2) As we know, fused AZS bricks have a dense structure, so two points should be noted in the kiln: First, its thermal conductivity is good. Therefore, after the low-temperature drainage process of the kiln is completed, the ballast should be temporarily pre-insulated in time, and a 10mm thick asbestos board should be used for insulation to increase the temperature of the outer surface of the ballast, so that the outer surface of the ballast can be fully expanded; secondly, the heating curve must be strictly followed to prevent large temperature fluctuations, especially after the fire, the operator must not relax his vigilance, because this is the critical moment for the rapid expansion of fused AZS bricks (800-1200℃), and a large change in temperature will cause the bricks to burst.

(3) As the kiln heats up, the refractory materials and steel structures in various parts of the kiln will change due to the gradual increase in temperature. Operators should frequently inspect and adjust the arch tie rods and top rods in time. Due to the uneven expansion of the arch, the adjustment must be moderately tight. According to practical experience, the expansion of the arch is not large during the entire kiln baking process, and the arch top rises by an average of 22mm during the entire kiln baking process. However, during high-temperature and heat insulation, the fused AZS bricks will shrink after a more intense expansion and stabilization. At this time, the inspection and adjustment of the arch tie rods and top rods should be more frequent, and the arch tie rods and top rods must be checked and adjusted once every 30 minutes.

(4) Since the sintering temperature of zirconium ramming material is not lower than 1400℃, it is required to be kept at 1450℃ for 2h after the high temperature, so that the ramming materials in the whole furnace and the arch brick seams can be sintered as much as possible to ensure the airtightness of the arch.

(5) The kiln baking personnel must carefully keep various technical records during the kiln baking, such as kiln pressure at different temperatures, air volume, expansion of the kiln, change in expansion joints, and the tightness of the tension rods, so as to promptly discover problems and deal with them, and provide the most reliable basis for future design, construction, and ignition of the kiln.