1. Refractory replacement standards
Refractory maintenance management, to implement the basic principle of replacement according to the standard, refractory brick replacement should be based on the thickness and strength of the residual bricks, combined with the integrity of the kiln skin, coal and raw materials, the next operation cycle target and the expected stability of the kiln condition for a comprehensive judgment, under the premise of ensuring the use cycle of refractory materials, and strive to reduce costs.
Refractory brick replacement standard in kiln
a) 2000-5000t D production line rotary kiln firing belt of the kiln skin unstable area, transition zone magnesium aluminum spinel brick 150mm, silicon brick kiln about 130mm, kiln skin stability area refractory brick thickness is less than 120mm, kiln tail domestic anti-spalling brick thickness is less than 100mm, can be considered replacement (inspection should be based on the kiln thermal characteristics, kiln skin conditions, refractory brick surface erosion conditions, operation records and the next cycle of operation objectives, Changes in coal and raw materials are comprehensively considered by the refractory management team).
b) In the single-ring bricks in the kiln, the thickness is lower than the above standards and the perimeter is within 1 4 rings, which can be considered to be dug and repairedWhen it is greater than 1 4 rings, the whole ring brick should be replaced.
Refractory brick replacement standard for other parts
a) When the residual thickness of the refractory brick in the plane part is lower than the original thickness 1 2, it can be considered to be replaced.
b) The residual thickness of the refractory brick of the arch part (such as the tertiary air duct) is lower than the original thickness of 2 5 or less, it can be considered to be replaced.
Refractory burner replacement standard
a) According to the local burning and spalling of the refractory castable, the implementation of digging and repair.
b) The refractory castable is uniformly burned in a large area, and the residual thickness is less than 100mm, which can be replaced as a whole according to the actual situation of the site.
c) For the castable at the kiln mouth and kiln tail, the wear, thickness, shedding, erosion and kiln mouth iron protection condition should be checked to determine whether it needs to be replaced.
d) If the top of the kiln hood is cracked, falling off, and the texture is loose, the whole will be replaced.
The refractory replacement approval procedure shall be carefully determined by the refractory management team of the base company according to the inspection status of the refractory and the operation target of the next cycle.
Second, the masonry of refractory materials
Pre-masonry quality requirements
The remaining materials in the kiln and the dismantled fire bricks should be removed, and the carcass should also be cleaned.
In the process of handling refractory bricks, the construction unit is cautious and strictly controls the damage rate of refractory bricks within 2%;The longitudinal reference line of the kiln should be put along the circumference in the shape of "ten" and symmetry, and each line is parallel to the axis of the kilnThe circumferential reference line should be placed every 4m along the axis, and each line should be parallel to each other and perpendicular to the kiln axis;The remaining materials in the kiln and the removed fire bricks should be all removed to ensure that the steel plate of the kiln body is clean and the corroded iron sheet is removedIt is strictly forbidden to put into use refractory bricks with edge damage and corner loss exceeding the control range.
Construction requirements for refractory bricks
Masonry quality requirements: brick joints are straight, ash mouth is even, arc surface is flat, and joints are tight. The interface of the new and old bricks is wet masonry, and the silica brick masonry must be wet masonry, and the change of brick type ratio should be noted.
Requirements for masonry fire clay: different quality mud should use different appliances, fire clay uses clean water, accurate weighing and modulation, and uniform mixing. The prepared mud shall not be arbitrarily diluted with water. The fullness of the mortar should be greater than 95 or more to ensure that the brick joints are dense, and the surface brick joints should be hooked with raw slurry. The parts of the shell that cannot be corrected are aligned with mud.
The refractory bricks of the wall should be staggered masonry, and when the bricks are joined with the calcium silicate board, they should be constructed step by stepDifferent calcium silicate boards are seamed, and expansion joints are left according to the design requirementsThe masonry shall not be skewed, the fullness of the mortar shall reach more than 95%, and the excess part of the mortar on the surface of the brick shall be scraped flatFor the wall of brick concrete structure, the castable part should be flat and smooth, and the bricks on the castable should wait for the castable to have a certain strength before it can be masonry
Refractory brick requirements during masonry: the top of the brick lining should be fully attached to the cylinder surface, no gaps should be left, and the adjacent single brick surface should be in complete contact with each other, and the length of the processed brick shall not be less than 50 of the original brick, and the thickness shall not be less than 80 of the original brick.
Precautions during construction: Hammers can not be used during construction to prevent the following phenomena of refractory bricks: inverted heads, drawing, mixing, dislocation, inclination, uneven ash joints, climbing, separation, heavy joints, mouth opening, hollowing, hair joints, snake bends, brick bulging, lack of edges and corners, etc.
Brick joint requirements: When the ring masonry method is built, the length of the selected bricks should be uniform, and the length deviation of the ring joint per meter should be less than 2mm, but the maximum deviation of the length of a single ring should not exceed 8mm.
Requirements for joint steel plate for bricklaying: the thickness is generally 1 2mm, and it is required to be flat, not curled, not twisted, and thorny. The width of the board is about 10mm smaller than the width of the brick. When masonry, the steel plate shall not exceed the edge of the brick, and shall not be inserted into the void and bridged. A maximum of one steel plate is allowed in each seam.
There are a large number of process holes in the preheater, calciner and rising flue, etc., which should be checked one by one, carefully constructed, the cone part should be constructed in sections, the slope of the inclined wall surface should be accurate, and the lining surface should be smooth, so as to ensure that the blanking is smooth in production and operation, and no material is storedBefore the construction of the kiln, a comprehensive inspection of the kiln shell should be carried out, the center line of the kiln cylinder should be straightened, the uneven places (welds, welding slag) on the shell should be polished, and the sundries in the kiln barrel should be cleaned.
Measuring and pay-off in the kiln: the longitudinal reference line of the kiln should be along the circumference of every 1Put one at 5m, and each line should be parallel to the axis of the kiln. The circumferential reference line should be placed every 10m, and the construction control line should be placed every 2m, and the circumferential lines should be parallel to each other and perpendicular to the axis of the kiln.
The basic requirements for bricklaying in the kiln are: the brick lining is close to the shell, the brick is close to the brick, the brick joint is straight, the intersection is accurate, the brick is locked, the position is good, and it does not sagging and emptying. It is necessary to ensure that the brick lining and the kiln body are reliably concentric during operation.
After the completion of the whole kiln refractory brick masonry, the brick lining should be comprehensively cleaned and tightened as necessary before ignition, and the ring must be checked, and the kiln should not be transferred after fastening.
Masonry method: when the length of the bricks is less than 4m, it can be manually masonry and supported by a top pressWhen the length of the bricks laid is greater than 4m, in order to speed up the bricklaying speed, a brick laying machine should be used. When laying bricks, it should be carried out in strict accordance with the requirements for the use of the brick laying machine and the quality requirements of the brick laying. When repairing the kiln and laying bricks, the manufacturing department (or safety production department) supervises the quality of bricklaying.
In the process of bricklaying, it is forbidden to directly knock the bricks with an iron hammer, and a wooden hammer or rubber hammer must be used.
The kiln technical management personnel do a good job of masonry records, and the content of the records is: masonry date, masonry parts, brick types and quality, technical leaders, and merchants.
Construction requirements for castables
Check the shape and cleanliness of the equipment before the construction of the castable, the type, layout, welding and expansion compensation treatment of the anchors, the uneven places (welds, welding slag) on the shell should be polished, and the surrounding anti-water loss measuresThe pre-test of the material, and the quality of the construction water.
The castable must be stirred with clean drinking water, the castable must be mechanically stirred and compacted, the amount of water added is strictly controlled by the product in accordance with the technical requirements of the product, the stirred castable is poured within 30 minutes, and the castable that has been agglomerated is strictly forbidden to be re-stirred or added with water.
Before construction, the reference line should be carefully placed, the anchors should be welded in the cyclone tube and the decomposition furnace ring beam, and the expansion joints should be reserved according to the drawings.
Expansion joints are retained: expansion joints must be set in the lining of large areas of walls, and the castable is pressed according to 1The area of about 5m is set, and the expansion joint should be left in the middle of the anchor interval. At the place where the top of the wall section supported by each layer of brick supporting is connected with the previous layer of brick board, a transverse expansion joint needs to be arranged, and the joint is filled with high-temperature resistant fiber cotton or refractory fiber felt. Generally, there is no expansion joint in the calcium silicate layer, and the expansion joint is generally less than 10mm.
The openings of the anchors should be staggered with each other, and the castable must be fully welded when welding, and the anchors should be wrapped with adhesive tape (or coated with asphalt, paraffin, etc.) to prevent the anchors from expanding and cracking by heating.
The vibration of the castable must be carried out in layers, the height of each layer is not more than 30mm, and the vibration spacing is about 250mm.
Large-area pouring construction should be layered and block construction, depending on the temperature of the part used, the area of each castable is controlled at 10-2.0m or so.
The surface of the insulation layer in contact with the castable must be coated with a waterproof agent, and the side of the formwork in contact with the castable must be coated with a separator (oil, asphalt, etc.) to prevent moisture absorption and facilitate demoulding. The fixation of the template should be firm and sealed. No slurry leakage. The castable strength can only be released when the strength reaches more than 70%. Be careful when demoulding. Tap gently to prevent damage to the castable. After the formwork is removed, check whether the surface of the castable is smooth in time. Whether there are holes and textured surfaces, and repair them in time. The serious problem must be chiseled, the anchor must be exposed, and then repaired with homogeneous castable, and it is strictly forbidden to smooth and cover the defect with cement mortar.
When the ambient temperature or furnace surface temperature is lower than 5 or higher than 40, the construction of refractory materials cannot be carried out. It is required that the mixing and stirring temperature of refractory materials should be higher than 5, before pouring or ramming construction, it should be ensured that it does not solidify, and the ambient temperature must still be controlled when air curing is carried out after construction, and the ambient temperature should be kept above the freezing point of the castable within 72 hours.
Construction requirements of calcium silicate board: large-area construction can be bonded with adhesive, and small-area construction or irregularities can be sawed into small pieces by hand saw;The calcium silicate board in the castable should be wound and fixed on the anchor with fine iron wire, and the surface should be brushed with waterproof material.