- Time:Nov 29, 2022
A. Refractory replacement standards
Refractory maintenance management, to implement the basic principle of standard replacement, refractory bricks should be replaced according to the thickness and strength of the residual bricks, combined with the integrity of the kiln skin, as well as coal and raw materials, the next operating cycle target and the expected stability of the kiln condition for a comprehensive determination, to ensure the use of the refractory cycle, while striving to reduce costs.
Kiln refractory brick replacement standard
1. 2000-5000t / d production line rotary kiln firing belt kiln skin instability area, transition zone magnesium aluminum spinel brick ≤ 150mm, silica-mo brick kiln ≤ 130mm or so, kiln skin stable area refractory brick thickness below about 120mm, kiln tail domestic anti-spalling brick thickness below 100mm or so, can be considered for replacement (check according to the kiln's thermal characteristics, kiln skin situation, surface erosion of refractory bricks and operating records and the next cycle of operation target, coal and raw material changes by the refractory management team for comprehensive consideration).
2. In the single ring brick of the kiln, the thickness is lower than the above standard and the circumference is within 1/4 ring, you can consider digging and mending; if it is greater than 1/4 ring, the whole ring brick should be replaced.
Other parts of the refractory brick replacement standards
1. The plane part of the residual thickness of the refractory brick is less than the original thickness of 1/2, can be considered for replacement.
2. Arch-shaped parts (such as three air ducts) of the residual thickness of the refractory brick, less than the original thickness of 2 / 5 below, can be considered for replacement.
Fire-resistant castables replacement standard
1. According to the local burn and spalling of refractory castables, digging and patching are implemented.
2. The refractory castable material is uniformly burned in a large area and the residual thickness is less than 100mm, the whole can be considered for replacement according to the actual situation on site.
3. For the kiln mouth and kiln tail castable material, it should be checked for wear, thickness, shedding, erosion and the condition of the kiln mouth iron guard to determine whether it needs to be replaced.
4. If the top of the kiln head cover is cracked, peeling or loose in texture, the whole is replaced.
ZHENJIN REFRACTORIES for refractory replacement reporting and approval procedures, required by the base company refractory management team, according to the state of inspection of refractory materials and the next cycle for the target, careful to determine the specific number of replacement and program.
B. The masonry of refractory materials
Quality requirements before masonry
Remaining materials in the kiln and the removal of fire bricks should be removed, ketone body also cleaned. The construction unit should be cautious in the process of refractory brick handling, and the breakage rate of refractory brick should be strictly controlled within 2%; the longitudinal reference line of the kiln should be put in four lines along the circumference in a "ten" shape and symmetry, each line parallel to the kiln axis; the circumferential reference line should be put every 4 meters along the axis, each line should be parallel to each other and perpendicular to the Kiln axis; kiln residual materials and removed fire bricks should be removed to ensure the cleanliness of the kiln steel plate, eradicate corroded iron; strictly prohibited side loss, corner loss more than the control range of refractory bricks into use.
Construction requirements for fire-resistant bricks
Masonry quality requirements: brick joints straight, uniform gray, arc surface flat, tight joints. New and old brick interface using wet masonry, silicone Mo brick masonry must be wet masonry, pay attention to the brick type ratio changes.
Masonry fire mud requirements: different quality mud to use different appliances, fire mud using clean water, accurate weighing modulation, uniform mixing. Tuned mud shall not be diluted with water arbitrarily. Mortar fullness requirements greater than 95%, to ensure that the brick joints are dense, the surface brick joints to be hooked with the original slurry. Shell can not be corrected parts with mud correction.
The refractory brick of the wall should be staggered masonry, when the brick is combined with silica calcium board, it should be constructed in steps; different silica calcium board through joints, and according to the design requirements to leave expansion joints; masonry should not appear skewed, mortar fullness of 95% or more, the excess part of the brick surface mortar should be scraped flat; brick concrete structure of the wall, cast material parts should be flat and smooth, the brick above the cast material should wait until the cast material has a certain strength before masonry.
Masonry refractory brick requirements: the top of the brick lining should be fully tightened with the cylinder face, no gaps should be left, complete contact between adjacent single brick large surface, the length of the processed brick should not be less than 50% of the original brick, the thickness should not be less than 80% of the original brick.
Precautions during construction: no hammer can be used during construction to eliminate the following phenomena in refractory bricks: size head inversion, draw, mixed slurry, misalignment, tilt, uneven gray joints, climbing, off-center, spoiled joints, open mouth, dehollowing, hairy joints, snaking bend, brick bulging, missing edges and corners, etc.
Brick seam requirements: ring masonry method of masonry, the length of the selected brick needs to be uniform, the deviation of the ring seam length per meter is less than 2mm, but the maximum deviation of the length of a single ring does not exceed 8mm.
Requirements for bricklaying jointing steel plate: thickness is generally 1-2mm, flat, no rolled edge, no distortion, no burr. The width of the plate is less than the width of the brick about 10mm. masonry steel plate shall not exceed the edge of the brick, shall not appear to insert empty, bridge phenomenon. A maximum of one steel plate is allowed to be used in each seam.
There are a large number of process cavities in the preheater, decomposer and rising flue, etc. The kiln is checked out one by one and carefully constructed. The cone part should be constructed in sections, the slope of the sloping wall surface should be accurate and the lining surface should be smooth to ensure smooth discharging and no storage of materials in production operation; the kiln shell should be thoroughly inspected before construction, the center line of the kiln barrel should be found to be correct, uneven places on the shell (weld seams and welding slag) should be polished, and debris in the kiln barrel should be cleaned.
Kiln measurement and placement: Kiln longitudinal datum line is placed every 1.5 meters along the circumference of the kiln, and each line is parallel to the axis of the kiln. The circumferential reference line is placed every 10 meters, and the construction control line is placed every 2 meters, with the circumferential lines evenly parallel to each other and perpendicular to the axis of the kiln.
The basic requirements for starting brick in the kiln are: brick lining close to the shell, brick and brick against tight, straight brick seam, accurate cross-ring, locking brick firmly, not to be dislocated, not to sag off the air. To ensure that the brick lining and the kiln body in operation reliable concentric.
After the full kiln refractory brick masonry is completed, the brick lining is fully cleaned and tightened as necessary before ignition, and the ring must be checked, and it is not advisable to turn the kiln again after tightening.
Masonry method: when the length of the brick laid less than 4 meters, can be manually masonry, top press support; when the length of the brick laid more than 4 meters, in order to speed up the brick laying speed, should use brick laying machine. Bricklaying should be strictly in accordance with the requirements of the use of bricklaying machine and bricklaying quality requirements to carry out. When repairing kiln bricklaying, bricklaying quality supervision is carried out by the manufacturing department (or safety production department).
During the bricklaying process, it is forbidden to hammer directly on the brick, you must use a wooden hammer or rubber hammer.
ZHENJIN REFRACTORIES requires kiln technical management personnel to make masonry records, which include: masonry date, masonry part, brick type and quality, technical person in charge, suppliers, etc.
Construction requirements for castables
Check the shape and cleanliness of the equipment, the type, arrangement, welding and expansion compensation treatment of the anchorages, the unevenness on the shell (welding seam, welding slag) to be polished, the anti-water loss measures around; the pre-test situation of the materials, and the quality of the water used for construction before the construction of the pouring material.
Casting material must be stirred with clean drinking water, the casting material must be mechanically stirred and vibrated, the amount of water added is strictly controlled in accordance with the technical requirements of the product over the pound, the stirred casting material is poured within 30 minutes, the lumped casting material is strictly forbidden to be re-mixed or used with water. Before the construction, we should put the datum line carefully, the anchors should be welded in the cyclone and decomposing furnace ring beam, and the expansion joints should be reserved according to the drawing.
Expansion joints left: expansion joints must be set for large area wall lining, and the casting material is set for every 1.5 square meters or so area, and the expansion joints should be left in the middle of the anchorages interval. The top of the wall section section supported by each layer of brick-supporting board is connected with the previous layer of brick-supporting board where the transverse expansion joints need to be set, and the joints are filled with high temperature resistant fiber wool or refractory fiber felt. Calcium silicate board layer generally does not set expansion joints, expansion joints are generally to be less than 10mm.
The openings of the anchorages should be staggered, the welding must be full welding, and the anchorages should be wrapped with adhesive tape (or coated with asphalt, paraffin, etc.) in order to prevent the anchorages from being expanded by heat and the casting material from cracking.
The vibrating 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 is appropriate. Large area casting construction should be done in layers and blocks, depending on the temperature of the part to be used, the area of each block of casting material should be controlled at about 1.0-2.0 square meters. The surface of the heat insulation layer in contact with the pouring material must be coated with water-proofing agent, and the template should be fixed firmly and sealed well. No slurry leakage. The strength of the castable reaches 70% or more before it can be demoulded. Be careful when demoulding. Knock gently to prevent damage to the casting material. Check whether the surface of the castable is smooth after the formwork is removed. Check whether there are holes and pockmarks, and repair them in time. The serious problem must be chiseled away to reveal the anchorage, and then repaired with homogeneous pouring material, forbidden to use cement mortar to cover the defect.
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 the refractory should be higher than 5°C. Before casting or pounding construction, it should be ensured that it does not solidify, and when air maintenance is carried out after construction, the ambient temperature must be controlled by throwing, and the ambient temperature should be kept above the solidification point of the castables within 72 hours.
Construction requirements of silica calcium board: large area construction can be glued firmly with adhesive, small area construction or irregular can be glued by hand sawing into small pieces; silica calcium board inside the casting material should be fixed by winding fine wire on the anchor parts, and the surface should be brushed with waterproof material.
