1. The following inspections should be strictly carried out before the construction of refractory castables
1.1 Check the appearance and cleanliness of the equipment to be poured;
1.2 Check the condition of construction equipment, vibrating tools, etc. must have intact spare parts;
1.3 Check the type, size, layout and welding quality of the anchors, and the metal anchors must be treated with expansion compensation;
1.4 Check the surrounding refractory brick lining and heat insulation layer to prevent water loss of the castable;
1.5 Check the packaging and delivery date of the refractory castable, and conduct a pre-experiment to check whether it is invalid;
1.6 Check the construction water, its water quality must reach the quality of drinking water.
If the above items fail to pass the inspection, the construction shall be carried out only after being qualified. Materials that have expired may not be used. During the construction of the castable, it is necessary to ensure that there is no power failure or interruption of the construction.
2. The template for refractory castable construction can be made of steel plate or hardwood. The template should have sufficient strength, good rigidity, no shape, no displacement, no slurry leakage. The steel template should be coated with release agent, and the wooden template should be painted with waterproof paint. Reused templates must be cleaned first, and then painted before use.
3. The amount of water added for refractory castables should be strictly controlled in accordance with the instructions for use, and should not exceed the limit. Under the premise of ensuring construction performance, the amount of water added should be less than more.
4. The mixing time of refractory castables should be no less than 5 minutes. Use a compulsory mixer during operation. When stirring, it is advisable to dry mix in advance, then add 80% water and stir, and then add the remaining water slowly and continue stirring according to the degree of dryness and wetness until a suitable working consistency is obtained. Clean the mixer first when mixing different castables.
5. The refractory castable must be used in the whole bucket and bag. The stirred castable is generally used up within 30 minutes. In a high-temperature and dry working environment, this time should be shortened appropriately. The castables that have been initially set or even agglomerated shall not be poured into the mold frame, nor shall they be mixed with water before being used.
6. The pouring material poured into the mold frame should be stratified by vibrating rod immediately, the height of each layer should not be greater than 300mm, and the vibration spacing should be about 250mm. Try to avoid touching the anchors during vibrations, and avoid prolonged or heavy shocks in the same location. After seeing the reflow of the castable surface, the vibrating rod should be slowly withdrawn to avoid segregation and voids in the castable layer. After the pouring is completed, the pouring body can no longer be compressed and shaken before solidification.
7. When pouring a large area, the construction should be divided into blocks. The appropriate area of each pouring area is about 1.5m2. Expansion joints should be set according to the design and should not be omitted. Expansion joints should be left at the intervals between the anchors.
8. After the surface of the castable is dry, immediately cover the exposed part with plastic film or straw bag. After the initial setting arrives, it should be regularly sprinkled with water for maintenance to keep the surface moist. The curing time should be at least two days, and water should be frequently sprayed on the first day. After the castable is finally set, the side mold can be removed to continue sprinkling maintenance, but the load-bearing template must be removed after the strength reaches 70%.
9. After the template is removed, the pouring body should be inspected in time. Quality problems such as honeycomb, peeling and voids should be dealt with and repaired in time. When the problem is serious, the defect should be chipped out to expose the anchorage, and then filled with the same quality tamping material to continue curing, and it is forbidden to use cement mortar to level it to conceal the problem.
