Aluminium oxide foam ceramic filter

Abstract

The present invention relates to a aluminium oxide foamed ceramic filter for filtering and purifying molten aluminium, aluminium alloy and copper. Said invention uses aluminium oxide, silicon dioxide, talcum and kaoline clay to form ceramic powder, and adds carboxyl methyl cellulose, polyvinyl alcohol, silica sol and water to prepare slurry, uses soft polyurethane foamed plastics as carrier and makes them undergo the process of impregnating said carrier with slurry, extruding to obtain blank material, drying and sintering so as to obtain the invented aluminium oxide foamed ceramic filter. Said foamed ceramic filter has good high-temperature stability in the molten aluminium alloy, does not contaminate alloy and possesses good filtering and adsorption efficiency for removing oxide impurity and flux impurity form molten metal, so that it can obtain obvious filtering and purification effect.

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 alumina as a ceramic component, and the filter prepared by the present invention is used for filtering and purifying metal melts such as aluminum, aluminum alloy, and copper. 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-q...

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

[0008] Aluminum alloy is easy to absorb gas and mix non-metallic impurities in the process of smelting and forming castings, thereby reducing the serviceability and processing performance of castings