Forming and application of refractory prefabricated parts
Refractory prefabricated parts are functional materials developed on the basis of traditional adventitious castable materials, and are high-temperature materials within the scope of refractory castables. They are made of refractory aggregates, powders, adhesives, additives, water or other liquids, and are cast into a fixed shape by casting. According to the different binders, they are divided into refractory cement bonding, phosphate bonding, water glass bonding, cement-free bonding, etc. According to the material, they can be divided into high-alumina prefabricated parts, corundum prefabricated parts, clay prefabricated parts, mullite prefabricated parts, etc.
This product can be prefabricated into a variety of shapes at will, with good thermal shock stability, high strength, good anti-stripping performance, and can effectively resist penetration and form an erosion layer in the application of heavy metal smelting furnaces. No joints, good airtightness, less heat loss, energy saving; can quickly repair the furnace and increase the running speed of the furnace; can realize the construction of direct lifting mechanized furnaces and kilns, with high construction efficiency.
Refractory prefabricated parts are widely used in various industrial furnaces and have irreplaceable advantages over refractory bricks. Its biggest advantage is that it can be pre-baked, which greatly shortens the construction period and has stable quality.
Casting material prefabricated parts are an important variety of refractory materials, and their proportion is increasing. The prefabricated parts of the castable material are first divided into small pieces, designed into special shapes for the parts to be built in high-temperature furnaces, and molds are made according to the shapes.
Baking is an important process in the production of prefabricated parts. During the baking process, most of the free water and combined water of the prefabricated parts themselves are discharged, and high strength is generated. Baking has a great influence on the quality of prefabricated parts, especially refractory prefabricated parts with high density, high strength and large volume, because the prefabricated parts themselves have high density and large size. The combined effect of water vapor pressure and thermal stress during baking can easily cause the prefabricated parts to peel off, and in severe cases, cause the prefabricated parts to explode. The baking of castable prefabricated parts generally adopts a temperature control method. During baking, several temperature measurement points are set in the drying kiln, and a baking curve is preset. The baking curve includes several heating and insulation parts. By monitoring the temperature of the temperature measurement points, the baking system is carried out according to the preset baking curve. This control method is simple and easy to operate, and is currently the main control method for baking refractory prefabricated parts and other materials. Casting material prefabricated parts are prone to bursting during baking, which is manifested as the casting material suddenly and violently peeling off from its structural surface or exploding into several pieces. Higher or faster baking temperatures cause prefabricated parts to burst. In addition to the normal discharge of water during baking, the high or fast baking temperature may cause excessive water vapor pressure and cause the prefabricated product to burst, which has the negative impact.