Correct Use Method of High Temperature Resistant Castables

2023-06-03 10:54:09

The construction of high-temperature resistant castables is carried out by the vibration method, which is widely used, including the construction of dry vibration materials.

1. Preparation before construction

According to the design size requirements, check and accept the construction quality of the previous process, and clean up the boiler construction site.

Transport the forced mixer, plug-in vibrator, and trolley to the boiler construction site, install it in place, and test run normally. The following table shows the technical indicators of the plug-in vibrator. It should be pointed out that the mixer is forced, the vibrating rod should be of high frequency, and there must be enough spare parts.

The template should have sufficient strength and rigidity, even if it is transported to the boiler construction site; the lighting power is connected, and the clean water is connected to the mixer.

High-temperature resistant castables are generally packed in bags, and materials such as anchor bricks, connectors, heat-insulating refractory bricks, silicon-calcium boards, asbestos boards, refractory clay bricks, and burner bricks should be transported to the boiler construction site at any time as required.

When the chemical binder is used, its concentration or density should be adjusted in advance and transported to the boiler construction site for use. Before use, it should be re-stirred evenly.

2. Verification of construction mix ratio

For bagged high-temperature resistant castables and their additives, before construction, samples should be sampled and tested according to the requirements of the design drawings or the manufacturer’s instructions, and the main performance should be inspected. When the high-temperature resistant castable does not meet the design requirements, the material should be replaced as soon as possible, and should not be sloppy. Therefore, this work is very important. From the time of purchasing high-temperature resistant castables, we must pay attention to their performance indicators. Qualified products are then used as the construction mix ratio of the boiler construction site according to the conditions of the boiler construction site and the storage time of the materials.

3. Masonry and formwork of the insulation layer

For the vibration construction of high-temperature resistant castables, this work also belongs to the construction preparation.

Before the construction of high temperature resistant castable furnace wall, first lay asbestos board, silicon calcium board or refractory fiber felt, etc., install metal connectors, place anchor bricks, secondly build heat-insulating refractory bricks or pour light high-temperature resistant castable; It is a support template. The working surface of the formwork is first coated with oil or stickers, and then close to the working end surface of the anchor brick for support. The height of each supporting formwork is 600~1000mm to facilitate feeding and vibration molding. When there is a fetal membrane, the fetal membrane is supported first, and then the template is supported. The surface of the heat insulation layer should be pasted with plastic film to prevent it from absorbing water and affecting the performance of the castable.

When the furnace wall is high, the masonry of the heat insulation layer should also be carried out in layers to prevent the pouring of the heat insulation layer when the pouring material vibrates.

During the construction of the refractory castable furnace roof, according to the requirements of the design size, the entire formwork should be firmly supported first, and then oiled; then the hanging bricks should be hung on the hanging beam with metal connectors, and some connectors need wooden wedges Fix the hanging bricks, and some don’t need to be fixed. The hanging bricks should be placed vertically with the furnace lining working surface, and the distance between the bottom end surface and the formwork surface is 0~10mm, and the end surface of the hanging bricks above 60% should be in contact with the formwork surface. When the spacing is greater than 10mm, the metal connector should be adjusted to meet the requirements. When there is a hole, the membrane should also be installed firmly, and then the formwork should be supported.

4. Mixing

A forced mixer should be used for mixing, and manual mixing can also be used when the amount of material is small. The variety of high-temperature resistant castables is different, and there are certain differences in mixing; bagged materials or refractory aggregates and cement, etc., the allowable error is ± 1.0 percentage points, the allowable error of additives is ± 0.5 percentage points, and the hydration liquid binder is allowed The error is ±0.5 percentage points, and the number of additives must be accurate; all kinds of raw materials are weighed and poured into the mixer without omission or addition.

For the mixing of high-temperature resistant castables such as cement, clay-bonded and low-cement series, first pour the bagged materials, additives, and additives into the bulk material, and pour them into the mixer for dry mixing for 1.0min, and then add water for wet mixing for 3~ 5min, the material can be discharged only after the material color is suitable. Then it is transported to the face of the palm and the fabric is started.

For the mixing of water glass high-temperature resistant castables, you can first put the powder or granules into the mixer for dry mixing, and then add water glass solution for wet mixing. After the particles are wrapped in the water glass, add refractory powder and other materials, and wet mix for about If the dry materials are mixed together, pour them into a blender for dry mixing for 1.0 min, add 2/3 of the water glass solution for wet mixing for 2~3 minutes, and then add the remaining binder for wet mixing. Stir for 2~3 minutes, and the material is ready to use. The mixing of resin-bonded carbon-containing high-temperature castables is similar.

For the mixing of high-temperature resistant castables such as phosphoric acid and phosphate, first, pour the dry material into the mixer for 1.0min and dry mix for 1.0min, add about 3/5 of the binder for wet mixing for 2~3min, then discharge the material, and transport it to the designated place for stacking, Cover tightly with plastic film, trap material, and trap material for more than 16 hours. The trapped material and coagulant accelerator are weighed and poured into the mixer for secondary mixing, and the remaining binder is wet mixed for 2-4 minutes before use.

When mixing high-temperature-resistant castables, if heat-resistant steel fibers, refractory fibers, and organic fibers need to be added to the materials, they should be continuously scattered into the mixer during the wet mixing process of the castables. In the material, stir while scattering, do not throw in agglomerates.

After the mixing material is out of the mixer, if it is too dry, too thin, or lacks certain materials, the material should be discarded and not added; the mixing material out of the mixer should be within 0.5~1.0h.

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