Silicon carbide foam ceramic filter

Abstract

The invention relates to a silicon carbide foam ceramic filter, which is composed of silicon carbide, aluminum oxide, silicon dioxide and talc as ceramic powder, and then adding carboxymethyl cellulose, polyvinyl alcohol, silica sol and water to prepare a slurry. The soft polyurethane foam is used as a carrier, impregnated with the above slurry, extruded to form a billet, dried and sintered to obtain a silicon carbide foam ceramic filter. The ceramic foam filter of the present invention has good high-temperature stability in molten iron and copper, does not pollute alloys, has good filtering and adsorption capacity for oxidized inclusions and flux inclusions in molten metals, and has good filtration and purification effects, and is heat-resistant Small capacity, no need to preheat when using, small resistance to fluid, large filtration capacity, and good performance in filtration and purification tests of iron and iron alloy melts.

Description

technical field [0001] The invention relates to the purification of molten metal, in particular to a foam ceramic filter. More specifically, the present invention relates to a ceramic foam filter containing silicon carbide as a ceramic component, and the filter prepared by the present invention is used for filtering and purifying ferrous metal melts. Background technique [0002] During the smelting and pouring process of various metal liquid alloys, the casting reject rate caused by casting defects such as non-metallic inclusions and shrinkage holes is generally as high as 50-60% of the total rejects. Inclusion defects not only seriously reduce the mechanical properties and casting properties of castings, but also have harmful effects on the machining and appearance of castings. Purifying liquid casting alloys, reducing or eliminating various non-metallic inclusions and exhaust gases are undoubtedly important technical measures to obtain high-quality castings. [0003] Fi...

AI Technical Summary

Problems solved by technology

However, all these filters can only filter out large inclusions and very few small inclusions in molten metal through mechanical sieving

Due to the low refractoriness and strength of the aluminum silicate fiber filter, it can only be used for filtering non-ferrous alloys, cast iron and small steel castings, and it is difficult to withstand the impact of high-temperature metal fluid for a long time; the molybdenum wire and Although the boron nitride fibrous filter screen developed in the United States can be used to filter high-temperature alloys such as cast steel, its application is limited because of its high price.

There are also straight-hole core-type ceramic filters and refractory particle filters used for casting alloy filtration, but their porosity is small, and the filtration efficiency of the former is still low, and the filtration effect is unstable. Bonding effect makes it easy to leak particles and inconvenient to use

Although the sintered porous ceramic filter first successfully developed in the United States in the early 1970s solved the problems of easy particle leakage and inconvenient use of the refractory particle filter, it is different from the honeycomb straight-hole ceramic filter successfully developed in the early 1980s in the United States. Like the container, the porosity is still small, generally less than 50%, so that the flow rate of the molten metal is low

[0009] However, the currently used silicon carbide foam ceramic filter still has the disadvantages of low high-temperature strength and unstable performance, especially the phosphate binder used can add undesirable impurities to the filtered iron and iron-based alloy melt , causing thermochemical instability of the melt