Al2O3-C refractory fired by nitridation and preparation method for Al2O3-C refractory

Abstract

The invention relates to an Al2O3-C refractory fired by nitridation and a preparation method for the Al2O3-C refractory. According to the technical scheme, the preparation method comprises the following steps of: mixing 55 to 94 weight percent of corundum, 5 to 20 weight percent of crystalline flake graphite, 1 to 30 weight percent of metal Si fine powder which serve as raw materials, adding a bonding agent in an amount which is 3.5 to 8 percent of the weight of the raw materials, and mixing and grinding for 10 to 30 minutes; and pressing the mixed and ground mixture to form a raw blank of the required Al2O3-C refractory, baking the pressed raw blank at the temperature of between 180 and 220 DEG C, putting into a high-temperature kiln, and keeping the temperature at the temperature of between 1,350 and 1,700 DEG C under the atmosphere of N2 for 1 to 8 hours to obtain the Al2O3-C refractory fired by the nitridation. The Al2O3-C refractory fired by the nitridation comprises a case-hardened Al2O3-C refractory brick, an Al2O3-C protective tube for the continuous casting of molten steel, an Al2O3-C sliding plate for the pouring of the molten steel and a nozzle brick. The Al2O3-C refractory has the characteristics of high strength, oxidation resistance, long service life and high performance of resisting the washing and erosion of high-temperature melts.

Description

technical field [0001] The invention belongs to Al 2 o 3 -C quality refractory technology field. In particular, it relates to a nitriding fired Al 2 o 3 -C quality refractory material and preparation method thereof. Background technique [0002] Since the 1970s, due to the rapid development of the iron and steel industry and the application of new technologies, there is an urgent need for new refractory materials with good durability to meet new needs. A lot of research work has been carried out on new high-performance refractory materials. Al 2 o 3 -C-quality refractories have been widely promoted and applied because of their good durability, especially in metallurgical high-temperature equipment such as ironmaking blast furnaces, torpedo-type mixed iron cars, and molten iron tanks. Al 2 o 3 -C-quality refractory material is the main high-temperature-resistant lining material, which is in an indispensable position. [0003] Al 2 o 3 -The core technology of C-qual...

AI Technical Summary

Problems solved by technology

However, C (flaky graphite) is easily oxidized at high temperature, that is, C is easily burned off at high temperature. When Al 2 o 3 -After the C of the C refractory material is oxidized, the Al 2 o 3 -The porosity of C-quality refractories increases and becomes porous and loose, and the strength of the material decreases significantly, resulting in a decrease in the material's ability to resist erosion and erosion by high-temperature melts, deteriorating the performance of the material, and greatly affecting the Al 2 o 3 -Use effect of C quality refractories

[0004] In order to solve the problem of C (flaky graphite) being oxidized under high temperature conditions, people have carried out a lot of research work, widely used in Al 2 o 3 - Adding anti-oxidant method to C refractory materials, the substances used as additives are mainly metal Al, Si, Mg and SiC, Si 3 N 4 etc., adding fine powders of these substances to Al 2 o 3 - C refractories are mixed uniformly with machinery. When high temperature oxidation occurs, these additives will firstly or simultaneously oxidize with C (flake graphite), which can slow down the oxidation process of C (flake graphite), but it is not effective for improving Al 2 o 3 - Grade C refractories do not contribute to the overall strength