How to build high alumina bricks?
How to build high alumina bricks?
High-alumina brick linings are divided into four categories according to the size of the brick joints and the degree of fineness of operation. The category and the size of the brick joints are respectively: Ⅰ ≤0.5mm; Ⅱ ≤1mm; Ⅲ ≤2mm; Ⅳ ≤3mm. The fire mud should be full in the mortar joints of the brick joints, and the brick joints of the inner and outer layers of the upper and lower layers should be staggered.
The following principles should be followed when preparing refractory mud for bricklaying.
2.1 Before bricklaying, various refractory slurries should be pre-experimented and pre-built to determine the bonding time, initial setting time, consistency and water consumption of different slurries.
2.2 Different tools should be used to prepare different muds and cleaned in time.
2.3 Clean water should be used for the preparation of different quality muds, the amount of water should be accurately weighed, and the mixing should be uniform, and use as needed. The hydraulic and air-hardening mud that has been prepared must not be used with water, and the mud that has been initially set must not be used.
2.4 When preparing the phosphate-bound mud, ensure the specified trapping time, and adjust it as you use it. The prepared mud shall not be diluted with water arbitrarily. Due to its corrosive nature, this mud must not be in direct contact with the metal shell.
The site should be thoroughly inspected and cleaned up before the brick lining is built.
Before the brick lining is built, the line should be laid out, and the size and elevation of each part of the masonry should be checked according to the design drawings.
The basic requirements of bricklaying are: tight bricks and bricks, straight brick joints, accurate cross circle, lock bricks, good position, no sagging and emptying, and the masonry should be kept flat and vertical. High-alumina bricks should be laid in staggered joints. The mud in the joints of the masonry bricks should be full and the surface should be jointed.
The layout of the use of different types of high alumina bricks is implemented according to the design plan. When laying brick lining, the fullness of the fire mud is required to reach more than 95%, and the surface brick joints should be jointed with the original slurry, but the excess mud on the brick lining surface should be scraped off in time.
When laying bricks, flexible tools such as wooden hammers, rubber hammers or hard plastic hammers should be used. Steel hammers should not be used, bricks should not be chopped on the masonry, and the masonry should not be beaten or corrected after the mud is hard.
It is necessary to strictly select bricks. Bricks of different materials and different types should be strictly separated, and bricks of the same quality and type should be selected with uniform length.
The thickness of the joint steel plate used for dry-laying is generally 1 to 1.2mm, and it is required to be flat, not crimped, not twisted, and free of burrs. The width of each slab should be less than the width of the brick by about 10mm. The steel plate shall not exceed the side of the brick during masonry, and the phenomenon of steel plate sounding and bridging shall not occur. Only one steel plate is allowed in each seam. Narrow steel plates for adjustment should be used as little as possible. The cardboard used for expansion joints should be placed according to the design.
When locking the bricks, flat bricks should be used to lock the bricks, and fine processing should be performed. The adjacent brick roads should be staggered by 1 to 2 bricks. It is strictly forbidden to lock bricks with castable alone, but castables can be used to fix the last lock brick.
The following common problems should be avoided when building fire-resistant and heat-insulating linings.
11.1 Dislocation: that is, unevenness between layers and blocks.
11.2 Oblique: That is, it is not flat in the horizontal direction.
11.3 Uneven gray seams: that is, the width of gray seams is different, which can be adjusted by selecting bricks appropriately.
11.4 Climbing: that is, the phenomenon of regular unevenness on the surface of the facing wall, which should be controlled within 1mm.
11.5 Separation from the center: that is, the brick ring is not concentric with the shell in the arc-shaped masonry.
11.6 Re-stitching: that is, the upper and lower ash seams are superimposed, and only one ash seam is allowed between the two layers.
11.7 Through seam: that is, the gray seams of the inner and outer horizontal layers are combined, and even the shell is exposed, which is not allowed.
11.8 Opening: the mortar joints in the curved masonry are small inside and large outside.
11.9 Void: that is, the mortar is not full between the layers, between the bricks and between the shell, and it is not allowed in the lining of the immovable equipment.
11.10 Hairy joints: the joints of the bricks are not hooked and wiped, and the walls are not clean.
11.11 Snaking: that is, longitudinal seams, circular seams or horizontal seams are not straight, but wavy.
11.12 Masonry bulge: It is caused by the deformation of the equipment, and the relevant surface of the equipment should be smoothed during the masonry. When the double-layer lining is built, the insulation layer can be used for leveling.
11.13 Mixed slurry: The wrong use of slurry is not allowed.
The fire-resistant and heat-insulating composite lining of masonry equipment shall be built in layers and sections, and it is strictly forbidden to build with mixed-layer mortar. The masonry heat insulation lining should also be filled with grout. When encountering holes and riveting and welding parts, bricks or plates should be processed, and the gaps should be filled with mud. Arbitrary paving, leaving gaps everywhere or using no mud is prohibited. In the thermal insulation layer, high-alumina bricks should be used for masonry under the anchor bricks, behind the arch-foot bricks, around the holes and in contact with expansion.
The expansion joints in the high-alumina brick lining must be set according to the design and shall not be omitted. The width of expansion joints should not have negative tolerances, no hard debris should be left in the joints, and the joints should be filled with refractory fibers to avoid the phenomenon of fullness and emptiness. Generally, there is no need for expansion joints in the thermal insulation layer.
The lining of important parts and parts with complex shapes should be pre-laid first. For linings with extremely complex structures and large processing volume of bricks, consider changing to castable linings.
The exposed metal parts left in the brick lining, including the brick supporting board, the brick retaining board, etc., shall be sealed with special-shaped bricks, castables or refractory fibers, and shall not be directly exposed to the hot kiln gas during use.
Anchor bricks are structural bricks of masonry, which should be kept in accordance with the design regulations and should not be omitted. No cracked anchor bricks shall be used around the hanging holes. The metal hooks should be laid flat and hung firmly. Hanging holes and hooks cannot be stuck, the gap left can be filled with refractory fiber.
When building capping bricks, joint bricks and curved bricks, if the original bricks cannot meet the sealing requirements, the bricks should be finished with a brick cutter instead of hand-processed bricks. The size of the processed bricks: the capping bricks should not be less than 70% of the original bricks; in the flat joint bricks and curved bricks, it should not be less than 1/2 of the original bricks. It must be locked with original bricks. The working surface of the brick is strictly prohibited from processing. The processing surface of the brick should not face the furnace, working surface or expansion joint.