KR20000072672A - Preparation Method of Alumina Refractory with melted mullite Particles - Google Patents

Abstract

PURPOSE: A manufacturing method of an alumina refractory material added melting mullite is provided to restrain a large grain boundary crack generated from the difference of the coefficient between a brick and the melting alumina by exchanging the large-sized melting alumina particle to the same melting mullite particle as the brick. CONSTITUTION: A manufacturing method of an alumina refractory material added melting mullite is provided to restrain a large grain boundary crack generated from the difference of the coefficient between a brick and the melting alumina. The alumina particles of 40% having 200μm of a particle size contain 10% of 500μm or higher of melting mullite powder, 10% of silica for producing a mullite brick. Each material is blended and milled in dry after adding binder. The milled materials are pressurized and sintered for 2 hours in an electric furnace at 1600°C.

Description

Preparation Method of Alumina Refractory with Molten Mullite {Preparation Method of Alumina Refractory with melted mullite Particles}

▲ Field of invention

In order to achieve high density and high refractoriness, this technology produces large grain boundary cracks caused by thermal expansion coefficient difference between matrix phase and oil alumina by replacing molten alumina particles with large molten alumina particles with matrix phases. It is a technology to suppress the formation of, and thereby improve the sintered density and high temperature strength.

▲ Prior art

① Conventional example

Refractories prepared by dispersing molten alumina particles having various particle sizes on mullite matrix have been produced.

▲ Describe the problem of existing technology

① The alumina refractories prepared by adding molten alumina have a large difference in the coefficient of thermal expansion and the matrix of mullite, which is large in size. Has a weakening problem (Fig. 1)

① This technology is to suppress the occurrence of large cracks generated between the molten alumina, the matrix phase, and the dispersed phase, and to improve the sinter density and fire resistance.

1 is an electron micrograph of a conventional A product showing the crack formed between the alumina particles and the matrix phase.

Figure 2 is an XRD analysis of the mullite-containing alumina refractory.

3 is an electron micrograph of a known mullite having a homogeneous structure

4 is a sintered density and water absorption rate of the moltenite dispersed alumina refractory

FIG. 5 is an electron micrograph showing binding between molten mullite particles and known mullite

Fig. 6 shows the degree of warpage (sag) which was tested for 1 hour at 1600 degrees to compare the degree of fire resistance.

① Composition

10% of molten lite powder having a size of 500 µm or more, 10% of silica for mullite matrix formation, 40% of various kinds of fused alumina particles having a particle size distribution of 200 µm or less, and 40% of alumina fine powder

② Manufacturing Method

Each powder is blended in composition to add a binder and dry ball milled. After milling to produce a molded body by uniaxial press in a press, and produced by sintering at 1600 ℃ 2 hours in an air atmosphere in an electric furnace.

③ Test result

-XRD analysis produced mullite-containing alumina refractory (Fig. 2).

On the matrix, a homogeneous structure of mullite was formed to combine alumina particles and mullite particles (FIG. 3).

-As a result of measuring the sintered density, the refractory was manufactured by improving the sintered density by 6% and lowering the absorption rate by 1.6% compared to the existing product (Fig. 4).

The results of electron microscopy showed that no cracking occurred between the molten mullite particles added and the known mullite, and a refractory having a perfect bond between the two phases was obtained (FIG. 5).

-The fire resistance was significantly improved at 1600 ℃ as compared with the existing product (Fig. 6).

Improves the density of alumina refractory;

-Suppresses the cracks occurring between the molten alumina particles and the mullite matrix.

-Improved fire resistance by suppressing crack

-Applicable to various new and high refractory refractory products.

Claims (1)

In the manufacture of high refractory alumina refractories with molten mullite -Method of manufacturing by adding molten mullite -Condition to suppress crack formation between matrix and grain by heat treatment