Damage to the refractory lining of rotary kiln often affects the continuity of production and is one of the common equipment accidents. The causes of the accident include design structure, refractory material quality, masonry quality and operation and maintenance. Through a comprehensive analysis of various lining damage accidents, it is helpful to find out some common causes and take preventive measures in advance to avoid accidents to the greatest extent.
Forms of refractories lining damage
1. Common forms of damage
The refractory lining of rotary kiln is subjected to the combined effects of mechanical stress, material friction, thermal stress, airflow and chemical erosion under the rotation state for a long time, which often leads to the following problems:
(1) The lifting block is subjected to the mechanical rotation gravity eccentricity effect, high temperature effect and stone impact friction for a long time, which causes the prefabricated block to twist, the refractory material to fall off, the thickness to reduce, and the refractory bricks filled between the lifting blocks to deform and fall off.
(2) Melting loss of high temperature calcined layer
(3) The airflow with large temperature difference in the kiln body causes the dust to be sintered into blocks and adhered to the surface of the refractory material through high temperature sintering. When the kiln body rotates, the separation of gravity causes the refractory material to partially peel off, the brick lining becomes thinner, the kiln body temperature increases, and the steel structure changes to varying degrees, reducing the service life of the kiln body.
2. Probability of various damages
The Refractory Technology Company conducted extensive experimental research on the refractory lining materials after use and calculated the probability of the main damage causes:
(1) Mechanical stress accounts for 37%: caused by the deformation of the cylinder and the thermal expansion of the bricks.
(2) Chemical erosion accounts for 36%: caused by the erosion of clinker silicates and alkali salts.
(3) Thermal stress accounts for 27%: caused by overheating and thermal shock.
With the different kiln types, operations and different positions of the kiln lining in the kiln, the above three factors play different roles, which mainly depend on the deformation state of the flame, kiln material and kiln cylinder during operation, so that the lining is subjected to various stresses.
