Ceramic foam filter (CFF) is a foam ceramic material with a three-dimensional grid structure and high porosity (70 to 90%). Because of its low density, high strength, high temperature resistance, large specific surface area, It has the advantages of large porosity and good filter adsorption, so it is widely used in metallurgy, chemical industry, light industry, food, environmental protection, energy saving and other fields.
As the third generation of filter equipment, foam ceramic material is particularly widely used in metal melting and casting production. 80 to 90% of domestic ceramic foams are used in the filtration and purification of molten metal, which has also promoted the rapid development of the domestic metal casting industry and improved the yield, machining performance and physical and chemical properties of cast metal products.
The three main categories of foam ceramic material are zirconia, silicon carbide and alumina foam ceramics. Among them, zirconia foam ceramics are used in the casting of high temperature (over 1500℃) steel and high-temperature alloys, and silicon carbide foam ceramics are used in medium temperature (1200℃). The above copper, iron casting, and alumina foam ceramics are used in the casting of non-ferrous metals, such as aluminum and aluminum alloys at low temperatures (about 700℃). The application fields of foam ceramics of different materials are different. Most of the existing foam ceramic production processes use organic foam impregnation sizing process, and the choice of sponge precursor has an especially important influence on the performance of foam ceramics.
The soft polyurethane porous mesh sponge used in foam ceramics is a closed-cell sponge foam, it is made of chemical raw materials such as toluene diisocyanate, polyether polyol, amine catalyst, etc. And then remove the surface film, and the holes are opened to form a porous sponge with a three-dimensional penetrating network structure. The open-cell polyurethane sponge is the type of polyurethane sponge required for the foam ceramic. In addition to having a three-dimensional network with three-dimensional through meshes, different material foam ceramics have different requirements for the polyurethane sponge carrier.