Cement pre-decomposition production line kiln refractory selection, in addition to price, usually should consider long service life, better insulation effect, simple masonry and faster masonry speed and easy maintenance, versatility And other factors.
Starting from masonry the cement klin, Rongsheng refractory castable factory provides a basis for customers to choose refractory materials for cement kiln for several special parts of cement rotary kiln.
Masonry of Three Special Parts in Cement Rotary Klin
1.Masonry of the High Extraction Part of the Rotary Kiln
Refractory mud can be directly used under the refractory brick, and the refractory brick and the kiln cylinder and the refractory bricks on both sides can be closely attached. The thickness of the refractory fire mud in the lower part of the refractory brick should not exceed 8mm, otherwise castables will affect the stable positioning of the refractory brick and the stability of the arch ring.
1) If the welding site exceeds 8mm.
2) For higher local welds, refractory castable can be removed by hand grinding.
3) For the weld seam with a longer part of the high fry, the grinding brick machine can be used to remove the refractory brick by the high part of the weld bead, so that the four corners of the refractory brick can be closely attached to the cylinder.
4)For longer welds that are higher than the cylinder, if the height is not high, the above methods can be combined.
Masonry of the Deformation Part of the Rotary kiln Cylinder
After a period of operation, the rotary kiln is often partially deformed by a local red kiln. In this case, it will be difficult to guarantee the quality of the masonry the cement rotary klin. Corresponding measures should be taken according to the specific situation. However, it must be ensured that the longitudinal brick joints are parallel to the axis, and the circumferential brick joints are perpendicular to the axis and coplanar. For the case of small deformation, refractory fire bricks of two different curvatures should be used for new combination according to the change of the local curvature radius, so that the refractory bricks can adapt to the curvature of the deformation part as much as possible. The refractory mud matched with the refractory brick is a kiln cylinder adapted to deform the refractory brick. When laying in this way, the maximum gap between the refractory bricks should not exceed 1.5 mm. The thickness of the refractory mud between the refractory brick and the casing does not exceed 8 mm.
Masonry of Refractory Castables at the Feed End
The masonry method of the refractory castable at the feed end is similar to the masonry method at the kiln end. The main points to note are:
The pouring height should be higher than the kiln seal ring not less than 50mm, so that the seal ring made of heat-resistant steel is retracted in the middle of the refractory castable. In this way, too much heat is not passed through the seal ring to the kiln cylinder. Due to the lack of metal shell support, the strength of this part of the castable material will be affected to some extent, and should be strengthened in the expansion joint and the setting of the nail.
There should be a gap of not less than 40 mm between the refractory castable and the feed tongue of the kiln exhaust chamber. This guarantees compensation for the following conditions:
1)Thermal expansion between the feeding tongue and the kiln cylinder.
2) Feeding tongue under high temperature condition, the deflection increases due to the decrease of rigidity, and the feeding tongue hangs down.
3)The kiln cylinder is deflected during installation and subsequent operation.
However, this gap should not be greater than 50mm. Excessive clearance will cause excessive gas flow rate and flow rate in the lower part of the feeding tongue, and bring too much refractory material into the sealing cavity to increase the tendency of the kiln tail seal to leak.
Masonry and Refractory Brick Selection of Interlocking Bricks in Arch Circle
1).Masonry of Interlocking Bricks in the Arch Ring
The locking brick refers to the brick that is finally built when the arch is rounded, semi-circular or less than semi-circular, and finally used to eliminate the gap between the fire brick and the refractory brick in the arch. The successful masonry of the lock brick will effectively prevent the loosening and core pulling of the refractory brick. Requirements are as follows:
Masonry vaults and round walls, when there are 5 to 6 bricks left in a circle, the first dry code refractory bricks should be taken care of, and the combination of bricks of different specifications should be used to meet the requirements of the wedge. If the requirements are not met, the size of the processed bricks needs to be carefully measured, and the refractory bricks processed by the size are again dry coded. The final space of the masonry is exactly the space occupied by the three original bricks that have not been cut in thickness.
The refractory brick surface of the processed brick shall not face the casing to prevent the refractory brick from being intimately attached to the casing.
The position of the locking brick should be 2 to 3 blocks away from the processing brick, and the locking operation should not be carried out at the top of the arch. Locking work should be carried out at equidistant positions on both sides of the vault.
The final locking brick must be in the gap between two original bricks that are not cut in thickness. The original brick that has not been processed is used to lock the brick to ensure the strength of the locking brick and reduce the wedge when the brick is wedged. friction.
The arch ring refractory bricks that are built by dry method are similar to the wet masonry, and should be wedged with a steel plate of 2 mm. The steel plate should be flat, free from irregularities, burrs, and rust-free. The head application wheel grinds a wedge angle of less than 60 to wedge. A brick joint can only be wedged into a steel plate, and a brick seam is prohibited from being wedged into two steel plates. The steel plate should not be wedged into the brick joint of the lock seam brick, and should be separated by 1 or 2 brick joints.
2)Selection and Processing of Arch ring Refractory Bricks
The arch ring is stabilized by the balance between the gravity of the refractory brick itself and the horizontal thrust acting on the arch brick. To this end, the arch ring refractory bricks should be able to withstand the compression of the arch ring and should have a certain strength. The brick type should have a certain degree of wedge, and the arched brick surface should be relatively flat, so that the refractory bricks maintain surface contact. This can maintain the stability of the arch ring better and for a long time under the condition of temperature change. The processing of arch refractory bricks should comply with the following requirements:
In addition to the low-strength insulating bricks, the refractory bricks can be processed with a hacksaw. Other refractory bricks must be processed by a brick cutting machine. It is strictly forbidden to cut and chisel with a hammer and a flat shovel.
The length of the processed brick should not be less than 1/2 of the original brick size, and its thickness should not be less than 70% of the original brick to maintain sufficient strength of the refractory brick. If a brick is less than the above specified after processing, two bricks should be processed.
It is strictly forbidden to cut bricks on the masonry. It is strictly forbidden to strike the masonry, which will cause direct damage or potential damage to the refractory brick.
Inspection of Kiln after Refractory of Rotary Kiln
After the refractory castable masonry of the rotary kiln is completed, itshould be carefully checked. The masonry plan to be lined should be properly arranged.
There is no bond between the dry refractory bricks, and there may be loosening of individual bricks. The inspection should be carried out at a 90 degree rotation. The loose part is wedged into a 2mm thick steel plate to tighten. The loose parts should be marked and wedged when transferred to the upper part. Each seam is only allowed to be wedged into a steel plate. If the masonry is loose, it should be wedged into the 4th to 5 fire bricks of the first steel plate and then wedged into the second steel plate. The stress of the steel plate is all wedged, and if it is wedged, the leaking part is divided by a gas cutting gun.
Secondly, the kiln should be ignited and put into production as soon as possible after the completion of the masonry. After the kiln cylinder is completed, the load is greatly increased, and it will fatigue and deform under the static load.
When the alkaline brick is left for a long time, the malignant transformation of MgO into Mg(OH)2 is caused by absorption of moisture, and it is damaged by volume expansion. This is true for magnesia bricks, especially for dolomite bricks.
The dry refractory bricks will undergo directional compression and sink, and the upper refractory bricks will loosen. If it is not possible to ignite immediately, the cement kiln should be slowly rotated to adjust the position to prevent deformation of the kiln. For the dolomite bricks, the method of paving lime is adopted to prevent the dolomite bricks from being damp to reduce the quality of the refractory bricks and shorten the service life. The kiln lining should be carefully checked before ignition, and if necessary, the steel plate should be wedged.
