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Cement Rotary Kiln Mining Machine

Cement Rotary Kiln Mining Machine

Cement Rotary Kiln Refractory Damage Is Too Fast

The reason for the low operating rate of cement rotary kiln is the wrong choice of refractory materials. In addition, there are several common refractory materials in cement rotary kiln, which will also lead to low operating rate of cement rotary kiln.

Structural Spalling

For large precalcining kiln, multi-duct coal nozzle is used, the air volume is large at one time, so the flame temperature is increased a lot, and the kiln head is strengthened. The flame temperature in the kiln is about 1700~1800°C, which makes the kiln mouth and cooling. The temperature levels of the belt, the firing belt, the filter belt, the decomposition belt and even the kiln door cover and the cooler are much higher than the corresponding parts of the conventional kiln.

When slag, dust, gas, or the like in contact with the heating surface invades the refractory material, a metamorphic layer is formed in the vicinity of the heating surface due to the action of these melting agents and heat, and the deteriorated portion is peeled off due to excessive shrinkage of the liquid phase, or deteriorated due to deterioration. The part is peeled off unlike the expansion of the undeteriorated part.

Prevention Method

Refractory materials which are not easy to generate structural spallation should be used. The load softening point and structural strength are high, and it is not easy to cause deformation or spallation. It can also be adjusted in the operation of the cement rotary kiln to reduce the stress on the refractory material. For example, cooling the kiln wall is effective for reducing the thickness of the metamorphic layer; or controlling the amount of material added to reduce the chemical load of the cement rotary kiln.

Mechanical Spalling

The pre-calcining kiln with a daily output of 2000t has a diameter of 4m, and the pre-calcining kiln with a daily output of 4000t has a diameter of 4.7 meters and a rotational speed of 3~4 rpm.

The kiln diameter is increased, the kiln temperature is increased, and the rotation speed is increased. The refractory brick rotates with the cylinder at high temperature, plus the support of the supporting wheel, the weight of the kiln and the impact of the material in the kiln, the mechanical vibration and deformation are intensified, and the fire resistance is intensified. The destruction of the material is also exacerbated, causing the refractory material to peel.

Preventive methods: For the prevention of mechanical stress, refractory materials with high temperature strength, corrosion resistance, thermal shock resistance and easy adhesion to the kiln skin can be selected; in installation, the refractory bricks should be sufficiently left with sufficient expansion joints; The heating can be slowly carried out, especially when the cement rotary kiln is ignited, the heating rate is controlled to prevent sudden heating, and the increased stress is caused.

Hot Peeling And Softening Damage

The thermal shock caused by the cyclic temperature difference per revolution of the cement rotary kiln, and the refractory material is subjected to quenching and rapid heat, the strain caused by the difference in surface and internal expansion causes the surface of the refractory material to be peeled off, and the refractory material is subjected to high temperature. The pressure of the material in the kiln reduces the compressive strength of the refractory material, and the refractory material is crushed and collapses.

Prevention methods: It is recommended to use refractory materials with high thermal shock resistance; or refractory materials with high softening point; in the operation of rotary kiln, try to avoid the occurrence of quenching and rapid heat, so as to reduce the strain caused by the expansion difference. Basically, no refractory material can cope with all the application conditions in cement rotary kiln, and the operating conditions of each cement rotary kiln are also different.

Therefore, if you want to effectively extend the life of refractory materials in cement rotary kiln, you should look for professional technical advice to know the correct way to use the product.

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