Refractory Castable Construction Process

1. Inspection before construction

Pre-construction inspections should be carried out strictly, including the following:

1.1 Clarify the appearance and structure of the castable equipment and clean it;

1.2 Setting of process holes;

1.3 The integrity of construction machinery and tools, vibrating tools, etc. must be in good condition;

1.4 Anchor type, size, layout, and welding quality, metal anchors must be compensated for expansion;

1.5 Preventive measures should be taken to prevent water (glue) loss of castables in the surrounding refractory brick insulation layer;

1.6 Packaging and factory date of castables, and conduct pre-tests to check for failure;

1.7 The quality of construction water must reach the quality of drinking water;

1.8 Implementation of construction process formula;

1.9 Pouring procedure.

If the above inspection fails, construction can only be carried out after passing the inspection. Expired materials shall not be used.

2. Formwork for construction

It can be made of steel plate or hardwood board (bamboo board). The formwork must have sufficient strength, good rigidity, no deformation, no displacement, and no leakage of slurry. Use mold remover for steel formwork and paint waterproof paint for wooden formwork. Reused wooden boards should be cleaned before use.

3. Castable lining construction

3.1 Mixing of castables

The mixing time should be no less than 5 minutes. A forced mixer should be used during operation. Dry mixing should be done first, then 80% of the solvent should be added for stirring. Then, depending on the degree of dryness and wetness and the requirements of the specific construction site, the remaining solvent should be slowly added until a suitable working consistency is obtained. On the premise of ensuring construction performance, the amount of solvent should be small.

The castables should be used in whole bags, and the mixed castables must be finished within 30 minutes. In high-temperature and dry working environments, the time should be shortened appropriately. Castables that have initially set or agglomerated should not be used, nor should they be stirred with solvent before use.

3.2 Vibration

As soon as the castable is poured into the formwork, it should be vibrated in layers with a vibrator. The height of each layer should be less than 300mm, and the vibration spacing should be 2500mm. When vibrating, try to avoid touching the anchors, not damaging the insulation layer, and not vibrating or re-vibrating in the same position for a long time. After the castable surface is re-slurried, the vibrator should be slowly pulled out to avoid segregation and cavities in the castable.

The poured body cannot be subjected to pressure or shock before solidification.

3.3 Pouring volume and expansion joints

When pouring in large-area construction, the pouring should be carried out in blocks. The area of each pouring area should be 1.5m2 (synchronized with the primary mixing volume). Expansion joints should be left as required (generally considered simultaneously during pouring) and must not be omitted. The expansion joints in the kiln and decomposition furnace are located in the axial direction of the annular ring, with no less than 4 expansion joints, made of aluminum silicate fiber felt.

3.4 Maintenance and demoulding inspection

After the surface of the castable is dry, perform necessary maintenance according to construction and maintenance requirements. Especially for castables that require water curing, sprinkle water regularly to keep the surface moist. After the castable is finally solidified, the side formwork can be removed to continue sprinkling and curing, but the load-bearing formwork cannot be demoulded until the strength reaches 70%.

After the formwork is removed, the pouring body should be inspected in time, and quality problems such as honeycombing, spalling, and voids should be dealt with and repaired promptly. When the problem is serious, the defective parts should be chiseled away to expose the anchors, and then filled with homogeneous tamping material to continue maintenance. Do not use mud to cover up problems.