Unshaped refractories must be properly baked after construction
Oven is a key link in the construction and use of unshaped refractories. Its function is mainly to remove free water and chemically bound water in the lining body and obtain high-temperature performance. Proper oven can increase the life of the kiln and thermal equipment. Otherwise, the water will not be removed smoothly, which will cause the lining to crack, reduce the strength, and even cause the lining to peel off or explode.
The baking system of unshaped refractory materials
is related to factors such as material variety and performance, construction and production methods, lining thickness and use conditions. Therefore, to formulate the baking curve of the lining body, all aspects should be fully considered. The general principle is that the temperature should be slowly raised and kept warm before 600°C, so that the moisture in the lining body should be fully removed.
When the lining is baked, the position of the thermocouple should generally be set at the position with the highest baking temperature and faster heating speed. At the same time, the hot end face of the thermocouple should be flush with the working surface of the lining body or retracted by about 5mm, so as to represent the temperature of the lining body more truly. In other words, the holding temperature referred to in the baking system is the temperature of the working surface of the lining.
When baking the lining, it is best to use gas, diesel or electric heating. These heat sources are easy to control, easy to use, and can ensure the baking quality; use wood or coal as fuel, and should be carefully operated to prevent flameout or overheating and damage to the lining ; The temperature of the lining body should be uniform and stable, and the baking system should be adjusted at any time according to the baking situation to ensure the baking quality.
In the kiln and thermal equipment, the unshaped refractory material
is used as the lining body, and it can be used after baking to reach the use temperature. If it is not used after baking, it should be slowly cooled down naturally without blowing cold air; if it is to be used, it should not be overheated, and it should be gradually heated to the use temperature at a temperature rise rate of 25~30℃/h before use.
During use, the unshaped refractory castable lining should not be exposed to water. If there is partial damage, it can be dug and repaired with the same material; if the furnace is stopped, the temperature should be naturally cooled. When restarting the furnace, the temperature rise rate is generally 150°C/h, and the maximum temperature should not exceed 250°C/h. When the furnace is stopped or opened improperly, it is easy to cause cracks or peeling of the lining, which reduces its service life.