Molten metal foam ceramic filter has an open-cell structure and a plurality of interconnected voids surrounded by ceramic fiber mesh. The porous structure of the filter helps filter molten metal. The molten metal is poured into a ceramic foam filter to remove entrained solids from the molten metal. The air permeability of the filter is 400 to 8000×10-7 cm2, the porosity is 0.80 to 0.95, the pore size is 5 to 45 holes per linear inch, and the thickness is from 1/4 to 4 inches.
Molten aluminum usually contains entrained solids, which are harmful to the final cast metal product. These entrained solids usually come from three sources. Some are alumina particles, the floating oxide layer on the surface sucks them into the liquid stream, and some of the entrained particles are fragments of the furnace lining, conveying trough, and other parts of the molten aluminum processing equipment, which are eroded and entrained in the furnace. . In the flowing aluminum stream, some particles are the precipitation of insoluble impurities, such as the precipitation of intermetallic compounds, borides, carbides or other aluminum compounds (such as chloride). When these impurities appear in the final cast product after the molten aluminum has solidified, they can cause the ductility of the final product to decrease or the finishing characteristics of the final product to be poor. Therefore, it is desirable to remove entrained solids from the molten aluminum stream before casting the molten aluminum stream into a solid, which can be used as it is or subjected to forming operations such as rolling, forging, extrusion, and the like.
The filtration process of removing entrained solids from the liquid is completed by porous filter media. Generally, filtering molten metals, especially aluminum, presents special problems because liquids are very aggressive and it is difficult to find a filter medium that can withstand liquids.
Generally, two filtration methods are used to remove entrained solids from molten aluminum alloys before casting. The most common filter medium is an open woven glass cloth screen that is placed in a metal transfer tank, near the nozzle or in the molten metal pool on top of the solidified ingot. These filters can only remove larger-sized inclusions from the metal, and are easily broken during use, because the glass fibers become very weak at the temperature of molten aluminum. In another prior art method, molten aluminum is filtered through a bed of loose alumina particles, such as tabular alumina, but it often suffers from the disadvantages usually associated with bed filters, namely that it allows too much solid to pass through, there is a strong trend. The formation of channels for effective use is prevented, and the pore size of the filter is not easy to control, but is easy to change under the conditions of use, so that even if the initial size is appropriate, its size cannot be effectively maintained. In addition, when the filter is not used, the metal must be kept in a constant molten state.
AdTech offers an improved ceramic foam filter for filtering and removing entrained solids from molten aluminum alloy. The molten metal foam ceramic filter adopts a material with an open-cell structure, and is characterized in that a plurality of interconnected voids are surrounded by a ceramic mesh. The use of ceramic foam filter greatly improves the filtration efficiency. High-efficiency ceramic foam material for filtering molten metal is characterized by improved strength reliability. Porous ceramic filter media has high strength and low cost.