For cement kilns, expensive refractory materials are not suitable for the entire kiln. The selection of refractory bricks for each part must match the working conditions.
Several principles for selecting materials for rotary kilns:
(1) It must meet the basic functions while minimizing the variety and number of refractory bricks.
(2) The lifespan should be matched as much as possible. For example, the lifespan of the front kiln mouth castables, upper and lower transition zones, and firing zones can be basically matched, and it is best if they can be repaired at one time.
(3) The overhaul cycle is controllable: ensure one overhaul per year and strive for two overhauls every three years.
Experience in selecting refractory brick materials for various parts
(1) Alkaline bricks must be used in the firing zone.
Alkaline bricks (excluding magnesia-alumina spinel bricks) must be used in the firing zone, such as direct combination of magnesia-chrome bricks, magnesia-iron spinel refractory bricks, dolomite bricks, etc., especially magnesia-iron spinel bricks and dolomite bricks. It is better to directly combine magnesia-chromium bricks with high quality and low price, but it has the disadvantages of environmental pressure and short service life.
The service life of mafic spinel bricks is between 6 and 10 months, and very few can reach 12 months. But if the lifespan reaches 12 months, the lifespan will be increased by at least 20%, and if it can reach 18 months, the lifespan will be increased by 50%, which is cost-effective.
(2) Selection of refractory materials for the upper and lower transition zones.
There are many choices for the upper and lower transition zones, such as magnesia-alumina spinel bricks, magnesia-iron spinel refractory bricks, silica-molybdenum red bricks, AZM1680 silica-molybdenum bricks, etc. Generally, magnesia-alumina spinel bricks and magnesia-iron spinel bricks have large thermal conductivity , the temperature of the cylinder will be high under the second-speed wheel belt, but the service life will be longer. If you use better quality silica-molybdenum red bricks, the temperature will be lowered a lot, and the service life can reach 18 months.
(3) Selection of safety belt refractory materials.
The selection of refractory bricks for safety belts (such as 40 m after Ф4.8 m High-strength alkali-resistant bricks last for 1 to 2 years, anti-flaking high alumina bricks for 2 to 3 years, and AZM1650 silicon molybdenum bricks for 3 to 5 years.
