Cement Kiln Refractory Construction Specification

Refractory material 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 brick, combined with the integrity of the kiln skin, as well as coal and raw materials, the next cycle of operation goals and expected stability of the kiln conditions to make a comprehensive judgment, in order to ensure that refractory materials under the premise of the use of the cycle, and strive to reduce costs.

 2000-5000t/d production line rotary kiln firing belt kiln skin unstable area, transition zone magnesium-aluminum spinel brick ≤ 150mm, silica brick kiln ≤ 130mm or so, the kiln skin stable area refractory brick thickness is lower than 120mm or so, kiln tail domestic spalling resistance brick thickness is lower than 100mm or so, can be considered for replacement (the inspection should be based on the kiln's thermodynamic characteristics, the kiln skin, the surface of the refractory brick erosion, as well as operating records and changes in coal and raw materials, etc. by the refractory management team to consider the comprehensive replacement of refractory materials). (The inspection should be based on the thermal characteristics of the kiln, kiln skin condition, surface erosion of refractory bricks, operation record and target of the next cycle of operation, change of coal and raw materials, etc., and be considered by the refractory material management team).

 In the kiln, if the thickness of a single ring of bricks is lower than the above standard and the circumference is within 1/4 ring, digging and patching can be considered; if it is larger than 1/4 ring, the whole ring of bricks should be replaced.

 When the residual thickness of the refractory bricks in the flat area is less than 1/2 of the original thickness or less, replacement may be considered.

 The residual thickness of the refractory bricks in the arched parts (e.g., three air ducts) may be considered for replacement if it is less than 2/5 of the original thickness.

 Digging and patching is practiced based on localized burnout and spalling of the refractory castables.

 The refractory castable material is uniformly burnt over a large area, and the residual thickness is less than 100mm, and can be considered to be replaced as a whole according to the actual situation of the site.

 For kiln mouth and kiln end castables, check for wear, thickness, peeling, erosion and kiln mouth iron guard condition to determine if replacement is needed.

 If the top of the kiln hood is cracked, peeling, or loose in texture, replace the whole thing.

The refractory replacement submission procedure is carried out by the base company's refractory management team, which carefully determines the specific replacement quantities and programs based on the inspection status of the refractory materials and the operational objectives for the next cycle.

The residual materials in the kiln and the removed firebricks should be completely removed, and the carcass should be cleaned.

Construction unit in the refractory bricks handling process, careful to strictly control the breakage rate of refractory bricks within 2%; should do a good job of placing lines, kiln longitudinal datum line along the circumference of the "cross", symmetry, put four lines, each line is parallel to the kiln axis; ring to the datum line along the axis of every 4m put a line, each line should be parallel to each other and perpendicular to the kiln axis; kiln residual materials and removed firebricks should be completely removed to ensure that the kiln body steel plate clean.

Each line should be parallel to each other and perpendicular to the kiln axis; the residual materials in the kiln as well as the removed firebricks should be completely removed to ensure that the kiln steel plate is clean and the corroded iron is eradicated; it is strictly prohibited to put into use the refractory bricks with edge loss and corner loss exceeding the control range.

 Masonry quality requirements: straight brick joints, uniform mortar, flat arc, tight joints. Wet masonry is used at the interface of new and old bricks, and the masonry of silica fume bricks must be wet masonry, paying attention to the change of brick type proportion.

 Requirements of masonry fire clay: different quality mud with different appliances, fire clay using clean water, accurate weighing modulation, uniform mixing. Modulated slurry shall not be diluted with water arbitrarily. Mortar fullness should be greater than 95% or more, to ensure that the brick joints are dense, the surface brick joints should be hooked with the original mortar. The shell can not be corrected parts with mud to find the right.

The refractory bricks of the wall should be masonry with staggered joints, and the bricks should be constructed step by step when they are joined with calcium silicate boards; different calcium silicate boards are through-jointed and the expansion joints are left according to the design requirements; the masonry should not be crooked, the mortar fullness reaches more than 95%, and the excess part of mortar on the surface of bricks should be scraped flat; for the wall of the brick concrete structure, the pouring parts should be flat and smooth, and the bricks on top of the pouring materials should be masoned after the pouring materials have a certain degree of strength.

 Masonry refractory brick requirements: the top of the brick lining should be fully affixed to the face of the cylinder, no gaps, adjacent single brick between the large surface to be completely in contact with the length of the processed brick shall not be less than 50% of the original brick, the thickness shall not be less than 80% of the original brick.

 Construction precautions: construction can not use the hammer, to eliminate the following phenomena of refractory bricks: the size of the head inverted, draw, mixed slurry, misaligned, tilted, uneven gray seam, climbing, away from the center, heavy seam, Zhangkou, out of the air, hairy seams, serpentine bends, bricks bulging, lack of prongs and corners, etc..

 Brick seam requirements: ring masonry method of masonry, the length of the selected bricks need to be uniform, the length of the ring seam per meter deviation is less than 2mm, but the maximum deviation of the length of a single ring does not exceed 8mm.

 Requirements for steel plate for bricklaying: the thickness is generally 1~2mm, and it is required to be flat, not curled, not twisted, and no burr. The width of the plate is less than the width of the brick about 10mm, the steel plate shall not exceed the edge of the brick when masonry, there shall be no insertion of empty, bridging phenomenon. A maximum of one steel plate is allowed in each seam.

Preheater, decomposition furnace and rising flue and so on there are a large number of process holes, to be checked one by one, careful construction, cone part of the construction should be divided into sections, the slope of the sloping wall surface slope should be accurate, the lining surface should be smooth, in order to ensure that the production operation of the downstream material is smooth, do not store the material; kiln construction should be carried out before the kiln shell for a comprehensive inspection, to find the kiln cylinder centerline, the shell on the uneven place (weld, weld slag) should be polished, the kiln cylinder debris to be Clean up the debris in the kiln tube.

 Kiln measurement and placement: kiln longitudinal datum line should be placed along the circumference of every 1.5m, each line should be parallel to the axis of the kiln. Circumferential datum line every 10m to put a construction control line every 2m to put a circumferential line should be parallel to each other and perpendicular to the axis of the kiln.

 The basic requirements of bricklaying in the kiln are: brick lining close to the shell, bricks and bricks against the tight, straight brick seams, the intersection of the circle is accurate, lock the brick firmly, not in place, not sagging out of the air. To ensure that the brick lining and kiln body in the operation of the reliable concentric.

After the completion of the whole kiln refractory brick masonry, before the ignition of the brick lining to carry out a comprehensive cleanup and necessary fastening, must be ring check, fastening should not be turned kiln.

 Masonry method: when the length of bricklaying is less than 4m, it can be manually laid and supported by top press; when the length of bricklaying is more than 4m, bricklaying machine should be used in order to accelerate the speed of bricklaying. Bricklaying should be carried out strictly according to the requirements of bricklaying machine and the quality of bricklaying. When repairing kiln bricklaying, the quality of bricklaying is supervised by the Manufacturing Department (or the Safety Production Department).

In the process of bricklaying, it is forbidden to use hammer to knock the bricks directly, and it is necessary to use wooden hammer or rubber hammer.

 Kiln technical management personnel to do a good job of masonry records, the content of the records are: the date of masonry, masonry parts, brick type and quality, the person in charge of technology, suppliers and so on.

Before the construction of the castables, check the shape and cleanliness of the equipment, the type, arrangement, welding and expansion compensation treatment of the anchors, the unevenness on the shell (weld, weld slag) should be polished, the surrounding measures against water loss; the pre-test of the materials, and the quality of construction water.

Clean drinking water must be used for mixing the castables, the castables must be mechanically stirred and vibrated, and the amount of water added should be controlled strictly according to the technical requirements of the products overweight, the stirred castables should be poured within 30 minutes, and it is forbidden to re-stir the castables that have been agglomerated or add water to use them.

Before the construction, the baseline should be carefully placed, and anchors should be welded in the cyclone and the ring beam of decomposition furnace, and the expansion joints should be reserved according to the drawings.

 Retention of expansion joints: large-area wall lining must be set up expansion joints, casting material is set up according to the area of every 1.5m2 or so, and the expansion joints should be left in the middle of the interval between the anchors. The top of the wall section section supported by each layer of bricklayer board and the last layer of bricklayer board connected to the place, need to set up transverse expansion joints, in the seam filled with high temperature resistant fiber cotton or fire-resistant fiber felt. Calcium silicate board layer is generally not set within the expansion joints, expansion joints are generally less than 10mm.

The openings of the anchors should be staggered, and the welding must be full welding, and wrapped with adhesive tape on the anchors (or coated with asphalt, paraffin, etc.) in order to prevent thermal expansion of the anchors and cracking of the castables.

The vibration of the casting material must be carried out in layers, the height of each layer is not more than 30mm, and the vibration spacing is about 250mm.

The construction of large-area casting should be divided into layers and pieces, depending on the temperature of the parts used, and the area of each piece of castable should be controlled at about 1.0-2.0M2.

The surface of the heat insulation layer in contact with the casting material must be coated with waterproofing agent, and the side of the template in contact with the casting material must be coated with isolating agent (machine oil, asphalt, etc.) to prevent absorption of water and facilitate demolding. The fixing of the template should be firm and well sealed. No slurry leakage. The casting material can be demolded only when its strength reaches more than 70%. Be careful when demolding. Tap gently to prevent damage to the castables. After removing the moldboard, check whether the surface of the castable is smooth. There are no holes, pockmarks, and timely repair. Serious problems must be chiseled to reveal the anchors, and then repair with the same quality of castables, it is strictly prohibited to cover the defects with cement mortar smoothing.

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. Requirements for refractory mixing and stirring temperature should be higher than 5 ℃, before pouring or pounding construction, should ensure that it does not solidify, after construction for air maintenance, must still control the ambient temperature, the ambient temperature in 72 hours should be kept above the solidification point of the castables.

 Construction requirements of calcium silicate board: large area construction can be glued with adhesive, small area construction or irregularities can be glued with hand saw into small pieces; calcium silicate board within the casting material should be fixed by winding fine wire on the anchors, and the surface should be brushed with waterproof material.