Brief description of the use of refractory bricks
Magnesia-aluminum spinel and magnesia-iron spinel are used in the firing zone instead of directly bonding magnesia-chrome bricks. Compared with the two, magnesia-aluminum spinel and magnesia-iron spinel have poor kiln-hanging performance and large thermal conductivity. Production often occurs in the production of fired zone refractory bricks when used for 6 to 8 months, high temperature points appear, concentrated at the two ends of the firing zone, 0.8~3m away from the kiln mouth and 18~23m. Every year, excavation and repairing are required to barely maintain The annual major overhaul will affect the continuous operation of the kiln.
Analysis of existing problems
2.1 Analysis of the causes of damage at 0.8~3m from the kiln mouth
Magnesite-Ferrum-alumina Spinel Brick every time there is a high temperature at the kiln entrance and the red kiln is shut down, the kiln skin is thin here, and the refractory bricks are peeled off seriously, usually about 5cm. There are even no bricks in some parts, and the cylinder is visible, and there is no dislocation. Analysis believes that this place is located at the junction of the firing zone and the cooling zone, with large temperature fluctuations, unstable kiln skins, frequent rises, and wear of the clinker out of the kiln, causing the refractory bricks to peel off and damage, and the bricks need to be adjusted.
2.2 Analysis of the causes of damage at 18~23m
Magnesite-Ferrum-alumina Spinel Brick due to the high magnesia of mine limestone, the average magnesia of clinker is about 5.0%. The specific composition is shown in Table 1. It can be seen from Table 1 that the liquid content of the clinker reaches 29.29%, and the crust value reaches 40.82%, both exceeding the upper limit of the good control value (the upper limit is 26% and 37% respectively), and the kiln is at 16~17m. There is thick kiln skin and ring formation. It is located in the post-sintering zone, the temperature is relatively low, and the kiln skin is not stable. In addition, there are rings on the front surface, and the clinker wears here and aggravates the damage of the refractory bricks.
