- Time:Jul 28, 2023
refractory castables must meet certain requirements and follow certain principles during masonry. During the construction process, the application of professional knowledge and experience is crucial to ensure the quality and reliability of refractory castable masonry. The following is an introduction to the technical requirements of refractory castables in masonry.
1. The safety protection meets the requirements of the group and the factory (restricted space, tagging and locking and verification, lighting, high-altitude operations, etc.).
2. Do not use castables that have expired in storage.
3. Completely remove the old refractory castables in the maintenance parts.
4. Even if a part is used, the whole bag of castable should be mixed.
5. It is strictly forbidden to mix impurities (raw meal powder, waste oil, solidified castables, etc.).
6. The anchors meet the requirements (material, height, diameter, variety), the welding rods meet the requirements, and the welding must not have false welding.
7. The expansion joint reserved for the anchor meets the requirements, and plastic caps are recommended.
8. The arrangement of anchors is generally 16-20 pieces/m2, and the staggered arrangement is preferred. See the technical requirements for anchors for details.
9. The laying of the insulation layer must be fixed with adhesive to ensure that the insulation layer is firm.
10. The insulation layer must be waterproofed (painted with a layer of insulating material such as bitumen or acrylic paint or covered with polyethylene cover) and ensured that it will not be damaged during pouring construction.
11. There shall be no gaps greater than 5mm in the insulation layer (between blocks) (except when RDF is used), and the gap of RDF kiln shall be reserved as 100mm.
12. The quality of the anchor and insulation layer can only enter the next process after passing the quality inspection.
13. The formwork is preferably a steel formwork, and the formwork at the hole and the observation hole must be prefabricated in advance and have a bell mouth (20°).
14. The surface of the template used must be cleaned and waterproofed (paraffin, grease, silicone or plastic film, etc.) to facilitate demoulding.
15. It is recommended to use airtight design (such as ㄣ form) for formwork installation, and the length of expansion joints shall be 6mm every 800mm (ceramic fiber felt needs to be 10mm, and it will become about 6mm after pouring).
16. The formwork is generally 20-30mm away from the top of the metal anchor. The support of the formwork must be firm and must not run away.
17. It is recommended to pour in blocks, and it is recommended to pour in an area of 800X800mm each time (the maximum is not more than 1000X1200mm), and the construction is carried out at intervals.
18. The height of formwork installation shall not be higher than 700mm each time, so as to avoid too high vibration and unrealistic.
19. The ceramic fiber felt used as the expansion joint is placed next to the template. If the ceramic fiber felt is not used, please consult the technical center.
2. The mixing of castables first follows the manufacturer's technical requirements, generally dry mixing for 30 seconds (if fiber needs to be added at this time), then add 80% water while stirring, and then add 20% water after stirring for 2 minutes , and then stir for 1 minute. Adjust the amount of water to be added according to the dry and wet conditions (the stirring time is set with a 25rpm high-speed mixer, and the stirring time is adjusted if the speed of the mixer is inconsistent).
20. The water used for castables must meet the drinking standard (PH 6-8, clean water), and the water temperature must be kept between 15-35°C, and the water must be heated or cooled when it is lower than 0°C or higher than 40°C
Vibration of castables uses immersion vibrating rods. The thickness of castables is 100-150mm thick using 50-type vibrating rods, and 150-300mm-thick using 70-type vibrating rods.
21. The pouring material shall be vibrated according to the arrangement of the anchors in real time, and shall not touch the shell and the anchors. It is enough to vibrate and muddy, and the time of vibrating in one place shall not be longer than 5 minutes.
A piece of castable is vibrated at one time.
22. Use up within the recommended time (20 minutes) and construct at a temperature (5-30°C), lower or higher than that, the working environment must be kept warm or retarder added.
23. The form removal time is not less than 12 hours after pouring. When removing the formwork, the sealing material in the castable must be cleaned up, and the cardboard and wood board must be removed.
24. Within 24 hours after the castable is poured, it is necessary to avoid excessive water loss on the surface of the castable (slow demoulding/surface spraying, etc.).
25. The castables for the kiln mouth and the equipment roof shall be constructed first, and the construction expansion joints at the expansion joints shall be inspected and accepted separately.
26. When using spray paint, refer to the above items for the retention of anchors and expansion joints, and pay attention to the rebound rate not greater than 15%.
27. If two layers of castables are used as the lining, the construction of the working layer must wait until the insulation layer is solidified before proceeding.
28. It is best to control the heating rate below 30 ℃/h. If necessary, vent holes can be made on the surface of the castable.
