As the third generation of molten metal filter equipment, foam ceramic filters are particularly widely used in metal smelting and casting production. Foam ceramic filters are used in the filtration and purification of molten metal, which has also promoted the rapid development of the metal casting industry and improved the yield, machining performance, and physical and chemical properties of cast metal products.
Ceramic foam filter (CFF) is a porous ceramic body with a three-dimensional grid structure and high porosity. 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.
The different materials application fields of foam ceramic molten metal filter equipment are different. The three main categories of foam ceramic filters are zirconia, silicon carbide and alumina foam ceramic filters.
Zirconia foam ceramic filters are used in the casting of high-temperature steel and high-temperature alloys.
Silicon carbide foam ceramic filters are used in copper and iron casting at medium temperature.
Alumina ceramic foam filter is used in the casting of non-ferrous metals such as aluminum and aluminum alloys at low temperatures.
Most of the existing foam ceramic filter production processes use organic foam impregnation sizing technology, and the selection of the sponge precursor has an especially important effect on the performance of the foam ceramic filter.
The soft polyurethane porous mesh sponge used in foam ceramics is a closed-cell sponge foam made of chemical raw materials, such as toluene diisocyanate, polyether polyol, amine catalyst, etc. The surface film layer is removed by acetylene, hydrogen and oxygen in proportion, 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 precursor.