Working Environment and Selection of Refractory Materials for Lining in Vertical Granulation

Working Environment and Selection of Refractory Materials for Lining in Vertical Granulation

The working environment of each part of the lining of the vertical granulation furnace is different, and the requirements for the selection of refractory materials are also different as follows:

1. Combustion chamber

   • Working environment: should withstand the high temperature of 1100-1120 ℃ and the pressure of 10-20 kPa, overpressure operation and high sealing requirements. Otherwise, gas leaks, fires and burns are easy to occur. It is also affected by the horizontal thrust of the vault floor and the lateral gas pressure on the furnace wall. Vertical kiln stops cause repeated expansion and contraction of the masonry, which can easily lead to its failure.

   • Selection of refractory materials: Generally, bricks or high-alumina bricks are used for the masonry, 701 mortar is used for important parts such as arches, and ordinary clay is used for the furnace floor and other parts. Refractory plastics can also be used for integral pressing.

2. Changing wind direction

   • Working environment: Supported by the lower metal water carrier, it is often exposed to high temperature, wear from dusty air flow, and also withstands the lateral pressure of the kiln charge. The masonry, especially where the water jet meets the masonry on the floor, has a high probability of collapse.

   • Choice of refractory materials: Generally, high-quality clay bricks, high-alumina bricks or yellow corundum bricks are used. In addition, synthetic silicon carbide corundum bricks can be used, which have excellent wear resistance, corrosion resistance and good thermal shock resistance.

3. Cooking area

   • Working environment: The temperature of the pellets can reach about 1250 ° C. Various chemical reactions occur in high-temperature oxidizing atmospheres. The decomposition of CaO by carbonates causes corrosion of the facing brick, which then cracks under the action of thermal stress. The friction of the downward movement of the pellets and the erosion of the upward air flow cause the loose surface layer to fall off. If the quality of the green ball is not satisfactory, the facing stone can be easily damaged. • Selection of refractory material: It is necessary to select a refractory material with high chemical resistance and dense structure. In China, high-alumina bricks are mainly used in new vertical pellet kilns.

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