- Time:Feb 24, 2023
A. Quality requirements before laying
1. The remaining materials in the kiln and the removed fire bricks should be cleared, and the cylinder body should also be cleaned.
2. The construction unit shall be cautious in the process of refractory brick handling, and strictly control the damage rate of refractory bricks within 2%.
3. The line setting work should be done well. The longitudinal reference line of the kiln should be placed in the shape of a "ten" along the circumference, symmetrically, and each line is parallel to the kiln axis; the circumferential reference line should be placed one every 4m along the axis, and each line They should be parallel to each other and perpendicular to the kiln axis.
4. The remaining materials in the kiln and the removed fire bricks should be completely removed to ensure that the steel plate of the kiln body is clean and remove the corroded iron sheet.
5. It is strictly forbidden to use refractory bricks with edge damage and corner damage beyond the control range.
B. Construction requirements for refractory bricks
1. Masonry quality requirements: straight brick joints, uniform gray openings, flat arc surfaces, and tight joints. Wet laying is used at the interface between new and old bricks, and silicon molybdenum bricks must be wet laid. Pay attention to the changes in the proportion of bricks.
2. Requirements for masonry fire clay: Different equipment should be used for different quality mud. Clean water should be used for fire clay, accurately weighed and prepared, and evenly mixed. The adjusted mud shall not be diluted with water arbitrarily. The fullness of the mortar should be greater than 95% to ensure that the brick joints are dense, and the surface brick joints should be jointed with original paste. The part of the shell that cannot be corrected is corrected with mud.
3. The refractory bricks of the wall should be built with staggered seams. When the bricks and calcium-silicon boards are joined, they should be constructed step by step; The fullness of the mortar should reach more than 95%, and the excess mortar on the brick surface should be scraped off; for the wall of the brick-concrete structure, the castable part should be smooth and smooth, and the bricks on the castable should wait for the castable to have a certain strength before they can be built.
4. Requirements for refractory bricks during masonry: the top of the brick lining should be fully attached to the surface of the cylinder without leaving gaps, and the large surfaces of adjacent single bricks should be in full contact. The length of the processed bricks should not be less than 50% of the original bricks, and the thickness should not be less than 80% of the original brick.
5. Precautions during construction: Do not use iron hammers during construction, and prevent the following phenomena of refractory bricks: inversion of size, drawing lots, mixing slurry, misalignment, tilting, uneven mortar joints, climbing, off-center, heavy seams, opening, Void, rough seam, snake bend, brick body bulge, lack of edges and corners, etc.
6. Requirements for brick joints: When building with ring masonry, the length of the selected bricks must be uniform, and the deviation of the length of the ring joint per meter is less than 2mm, but the maximum deviation of the length of a single ring does not exceed 8mm.
7. Requirements for slotted steel plates for bricklaying: the thickness is generally 1-2mm, and it is required to be flat, not curled, not twisted, and without burrs. The board width is about 10mm smaller than the brick width. During masonry, the steel plate shall not exceed the edge of the brick, and no gaps or bridging shall occur. A maximum of one steel plate is allowed in each seam.
8. There are a large number of process holes in the preheater, calciner and ascending flue, which must be checked one by one and carefully constructed. The cone part must be constructed in sections, the slope of the inclined wall surface must be accurate, and the lining surface must be smooth. To ensure smooth feeding and unloading during production operation without stockpiling.
9. Before construction in the kiln, it is necessary to conduct a comprehensive inspection of the kiln shell, align the center line of the kiln barrel, polish the uneven parts (welding seams, welding slag) on the shell, and clean up the sundries in the kiln barrel.
10. Measurement and setting-out lines in the kiln: The longitudinal reference line of the kiln should be placed every 1.5m along the circumference, and each line should be parallel to the axis of the kiln. One circular reference line is placed every 10m, and one construction control line is placed every 2m. The circular lines should be parallel to each other and perpendicular to the axis of the kiln.
11. The basic requirements for laying bricks in the kiln are: the brick lining is close to the shell, the bricks are tightly connected to each other, the brick joints are straight, the intersection circles are accurate, the bricks are locked firmly, not in place, and not sagging out of the void. It is necessary to ensure that the brick lining and the kiln body are reliably concentric during operation.
12. After the refractory bricks of the whole kiln are built, the brick lining must be fully cleaned and necessary fastened before ignition. It must be inspected in a circle, and it is not suitable to turn the kiln after fastening.
13. Masonry method: When the length of the bricks is less than 4m, it can be built manually and supported by a press; when the length of the bricks is greater than 4m, in order to speed up the speed of bricklaying, a bricklayer should be used. When laying bricks, it should be carried out in strict accordance with the requirements for the use of bricklaying machines and the quality requirements of bricklaying. When repairing kilns and laying bricks, the manufacturing department (or safety production department) will supervise the quality of bricklaying.
14. During the bricklaying process, it is forbidden to knock bricks directly with an iron hammer, and a wooden hammer or rubber hammer must be used.
15. The technical management personnel of the kiln shall make a record of the masonry, and the record content is: the date of the masonry, the location of the masonry, the type and quality of the brick, the person in charge of the technology, the supplier, etc.
C. Construction requirements for castables
1. Check the shape and cleanliness of the equipment before construction of the castable, the type, layout, welding and expansion compensation treatment of the anchor, the uneven parts (weld seam, welding slag) on the shell should be polished, and the surrounding water loss prevention measures; materials Pre-test conditions and construction water quality.
2. Clean drinking water must be used for mixing the castable. The castable must be mechanically stirred and vibrated. The amount of water added is strictly controlled in accordance with the technical requirements of the product. The pouring of the stirred castable is completed within 30 minutes, and the castable that has agglomerated It is strictly forbidden to re-stir or add water to use.
3. Before the construction, the reference line should be carefully placed, the anchors should be welded in the cyclone and the ring beam of the decomposition furnace, and the expansion joints should be reserved according to the drawings.
4. Retention of expansion joints: Expansion joints must be set in the lining of large-area walls, castables should be set in every 1.5m2 area, and expansion joints should be left in the middle of the interval between anchors. At the place where the top of the wall segment supported by each layer of supporting brick boards is connected to the previous layer of supporting brick boards, transverse expansion joints need to be provided, and the joints are filled with high temperature resistant fiber cotton or refractory fiber felt. There is generally no expansion joint in the calcium silicate board layer, and the expansion joint is generally less than 10mm.
5. The openings of the anchors should be staggered with each other. When welding, they must be fully welded, and the anchors should be wrapped with adhesive tape (or coated with asphalt, paraffin, etc.) to prevent the anchors from expanding due to thermal expansion and cracking of the castable.
6. Vibration of castables must be carried out in layers, the height of each layer is not greater than 30mm, and the vibration distance is preferably about 250mm.
7. Large-scale pouring construction should be carried out in layers and blocks. Depending on the temperature of the used parts, the area of each castable should be controlled at about 1.0-2.0M2.
8. The surface of the heat 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 release agent (oil, asphalt, etc.) to prevent moisture absorption and facilitate demoulding. The formwork should be fixed firmly, with good sealing performance and no slurry leakage. The castable can only be demolded when its strength reaches more than 70%. Be careful when demolding and tap lightly to prevent damage to the castable. After the formwork is removed, it is necessary to check whether the surface of the castable is smooth, whether there are holes or pockmarks, and repair it in time. Serious problems must be cut open to expose the anchor, and then repaired with homogeneous castables. It is strictly forbidden to use cement mortar to smooth and cover up defects.
9. When the ambient temperature or furnace surface temperature is lower than 5°C or higher than 40°C, 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°C. Before pouring or ramming construction, it should be ensured that it does not solidify. When air curing is completed after construction, the ambient temperature must still be controlled. The ambient temperature should be kept at 72 hours. Above the freezing point of the castable.
10. Construction requirements for calcium-silicon board: large-area construction can be bonded firmly with adhesives, small-area construction or irregularities can be sawed into small pieces with hand saws; the calcium-silicon board in the castable should be anchored with fine iron wire Wrapped and fixed on the parts, the surface should be brushed with waterproof materials.
ZHENJIN REFRACTORIES has 38 years of experience in the refractory industry, and is committed to one-stop general contracting services such as R&D and manufacturing of refractory materials for cement, lime, nonferrous metals, steel and other industries, technical solution design, construction and supporting product provision. The service chain runs through the entire life cycle of the project, including preliminary consultation, scheme design, R&D and production, furnace construction and safety production. Through the optimized combination of various brand products, it can meet different process requirements and create value for customers.
