The Reason Of Firebrick Falling Off in The Drying Process Of New Cement Kiln
Brick lining of rotary kiln is an important equipment to ensure the continuity of cement clinker production. Therefore, if the rotary kiln is an important machine, then the firebrick lining is the motor. However, there are many cement plants in the new rotary kiln will appear in the kiln refractory brick phenomenon, do not know how to do. What is the reason? The main reason is that the refractory bricks are not locked during the masonry process.
1: Analysis of the causes of brick dropping during the drying process of refractory bricks
(1) Improper use of cement. In the process of masonry, it is necessary to use mortar to bond the refractory bricks laid by rotary kiln, and it is also necessary to use mortar to level the refractory bricks. When the mortar is not evenly applied, it is easy to lead to the imbalance of the type proportion of refractory bricks, resulting in the tilt of the brick surface and the inconsistency of the size and tightness of the brick head. The use of mortar has a particularly prominent impact on winter construction. Due to the decrease of ambient temperature, the fluidity of refractory mortar becomes poor and freezing occurs. When the whole ring is locked with channel steel plate, the mortar has been frozen, but during the heating process of the kiln body, the mortar begins to melt, and the mortar in the brick joint is lost under the gravitational extrusion of the refractory brick, resulting in the increase of the refractory brick in the ring joint, loose and fall off, resulting in the brick dropping accident.
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(2) The locking degree of each round of firebrick is not enough. When laying bricks with a bricklaying machine, it is common to lock each circle of bricks in place at once. Only when it is properly locked does the construction of the next ring begin. After the bricklaying is complete, use a sledgehammer to add a joint steel plate to the top of the refractory brick in the kiln from the end to the kiln head. This masonry method has a disadvantage: because it is not locked at the beginning, the refractory brick will inevitably slide downward under its own gravity, resulting in the refractory brick floor and the inner wall of the kiln are not tight, and there is a gap phenomenon. When the void phenomenon is formed, the locking joint steel plate will only increase the tightness between the circular refractory brick and the brick, and will not change the void problem when the temperature rises to a certain degree, and will aggravate the void phenomenon when the rotary kiln needs to be turned over intermittly.
(3) The pressure of the bricklaying machine is insufficient. The working pressure of the bricklaying machine is not enough to support the refractory brick and can not make it close to the kiln barrel, resulting in a slight gap phenomenon. In the construction process, it is necessary to ensure that the air supply pressure of the air compressor is between 0.55mpa and 0.65Mpa, which is our weakness. During winter construction, because the compressed air pipeline connected with the masonry machine is longer and the thickness of the connecting pipe is different, the air compressor has the problem of oil-water separator, the air storage tank does not often release water, and the connecting pipe leaks. The lack of air supply pressure of the bricklaying machine will lead to the lack of pressure of the top brick of the bricklaying machine, forming the bottom gap of the refractory brick.
2: Solutions and preventive measures
(1) When locking bricks, the bottom surface of the refractory brick of the rotary kiln must be as close as possible to the inner wall of the kiln. Once a ring is locked, the next ring can be placed. After the completion of masonry, the locking iron plate should be added in the rotary kiln. When tightening the iron plate, the position below the center line of the rotary kiln should be tightened as far as possible to ensure that there are locked iron plates at 90°, 180°, 270° and 360° of the circumference of the rotary kiln, and two slotted plates are allowed.
(2) Before masonry, the supporting mortar of refractory brick of rotary kiln should be selected, and its material, including various physical and chemical indexes, should be matched with refractory brick. The mortar that is not allowed to be used does not match the refractory brick material.
(3) Before masonry, a circular line should be set in the kiln shell every 2m, and the circular line should be parallel to the girth weld of each section of the cylinder. When laying the firebrick floor, it must be constructed according to the axis and the ring line. Check every 5 turns to measure whether the distance between the ring peak and the circumference line is consistent. Adjust the firebrick back ring according to the distance deviation. It is not allowed to be achieved in one step, it should be adjusted gradually. At the same time, it should be controlled within 2 mm.
(4) Try to avoid cutting and processing bricks. If the length of the processed brick is less than the length of the original brick, the adjacent standard brick should be removed. Standard brick and small processing brick should be used in staggered masonry to eliminate ring peaks. Wet masonry must be used in joint masonry, and the effect of high temperature mortar is good.
Conclusion: Experienced construction team is the best choice for the masonry of refractory brick of rotary kiln. Before the material enters the factory, some acceptance tests should be carried out to prevent the use of unqualified products. Static acceptance and dynamic acceptance should be carried out before delivery of rotary kiln masonry refractory bricks to the owner.
JIYGO REFRACTORY & ABRASIVE LIMITED
