Alkaline refractories have excellent properties of high temperature resistance to calcination and chemical corrosion resistance, and are the key kiln lining materials for achieving high quality, high yield, low consumption and long-term safe operation of cement kiln. The fused magnesia brick has the main disadvantages of being susceptible to moisture deterioration, high thermal expansion rate, high thermal conductivity and poor thermal shock resistance. At present, the imported and domestic alkaline refractory materials suitable for cement kiln mainly include direct combination of magnesia chrome brick, semi-direct combined magnesia chrome brick, ordinary magnesia chrome brick, dolomite brick, zirconium and zirconium-free special magnesia bricks. Spinel and chemical combination do not burn magnesia chrome bricks. The physical and chemical properties of several refractory bricks are shown in the following table: high alumina bricks

High alumina bricks have high compressive strength and load softening temperature as well as good thermal shock resistance. Because of its low price and high quality, it is widely used in various cement kilns. Various types of phosphate-bonded high-alumina bricks are characterized by high strength (not less than 60 MPa) and good thermal shock resistance, but they have high creep at high temperatures, so they are used for high calcination at the top of the arch. Aluminum bricks are good.

In high alumina bricks, the introduction of a small amount of ZrO2, using the phase transition between ZrO2 monoclinic and tetragonal, can lead to the existence of microcracks and the improvement of thermal shock resistance. Choosing the appropriate particle grading gives the brick a higher apparent porosity, but also a higher strength, which reduces its thermal conductivity and thermal expansion. A glazed film of a transitional surface is used in the cement kiln to protect the brick from further alkali corrosion.

The high-aluminum bricks suitable for cement kiln mainly include phosphate-bonded high-alumina bricks, phosphate-bonded high-aluminum wear-resistant bricks, anti-flaking high-aluminum bricks, chemically bonded (special) high-aluminum bricks, and ordinary high-aluminum bricks.

Series alkali-resistant brick

The alkali-resistant brick has excellent alkali corrosion resistance, and under certain conditions, it can react with the alkali compound in the kiln material and the kiln gas and rapidly form a closed dense protective glaze layer on the turn, preventing the incontinence and the alkali of the brick. One of the indispensable kiln lining materials is the cracking kiln, especially the new dry kiln. The series of alkali-resistant bricks include ordinary alkali-resistant bricks, high-strength alkali-resistant bricks, alkali-resistant heat-insulating bricks and vault-type alkali-resistant bricks.

Series refractory castable

The refractory castable has the characteristics of simple production process, energy consumption, flexible use and so on. In the cement kiln system, the application in the complex preheater system is becoming more and more popular. The refractory castables suitable for cement kiln mainly include corundum castables, high alumina castables, alkali-resistant castables and lightweight castables.