- Time:Aug 21, 2023
Unshaped refractories, also known as monolithic refractories, refer to refractories that are directly constructed without going through a forming mold. Compared with traditional brick or block refractory materials, unshaped refractory materials are widely used for their flexibility, construction convenience and ability to adapt to various shape requirements.
Unshaped refractories are mainly composed of refractory aggregates, binders and additives. Refractory aggregates can be high-temperature stable granular materials such as alumina, silicon oxide, and silicon carbide. The binder is a material that binds the aggregates together by providing cohesive force. Common binders include water glass, phosphate, cement etc. Additives include plasticizers, anti-cracking agents, preservatives, etc., which are used to improve the plasticity, crack resistance and corrosion resistance of materials.
The construction methods of unshaped refractories mainly include the following:
1. Castable: Mix refractory aggregate, binder and water to form a flowable slurry, then pour it into the construction site, and form a refractory layer after curing.
2. Spraying: The unshaped refractory material is made into a sprayable paste slurry, which is sprayed onto the surface to be protected by a spray gun to form a uniform refractory layer.
3. Infusion (Gunning): The semi-dry paste material is made from the amorphous refractory material, which is injected into the construction site through high-pressure injection or artificially, and finally a solid refractory layer is formed during the construction process.
4. Assembly (Plastic): add an appropriate amount of water to the unshaped refractory material, stir it into a plastic shape, and directly assemble it to the desired position by hand or machine, and then dry or solidify to form a strong refractory layer.
