Al2O3-Cr2O3 refractory material for smelting reduction iron smelting furnace

Abstract

The invention belongs to the field of refractory materials for smelting reduction iron smelting and provides an Al2O3-Cr2O3 refractory material for a smelting reduction iron smelting furnace. The Al2O3-Cr2O3 refractory material for the smelting reduction iron smelting furnace comprises the following raw material components in percentage by mass: 60-70% of aggregate and 30-40% of matrix; content of Cr2O3 in the Al2O3-Cr2O3 refractory material is 30-55%; the aggregate comprises alumina-chrome particles and a zirconium-containing raw material; the zirconium-containing raw material is one of zirconium mullite particles and zirconite particles or combination of the two particles; addition amount of zirconium mullite and zirconite is 2-15% of the total mass of the raw material; the matrix is fine powder and micro powder, the fine powder comprises chromium oxide green and alumina-chrome fine powder; and the micro powder is zirconia micro powder and sintered alumina micro powder or activated alumina micro powder. The Al2O3-Cr2O3 refractory material for the smelting reduction iron smelting furnace has the advantages that thermal shock resistance of the material is effectively improved while guaranteeing excellent sintering effect and slag resistance of the material and operation cost is saved.

Description

technical field [0001] The invention belongs to the field of refractory materials for smelting reduction ironmaking, and mainly relates to an aluminum alloy for smelting reduction ironmaking furnace. 2 o 3 -Cr 2 o 3 refractory material. Background technique [0002] The smelting reduction ironmaking technology uses non-coke pulverized coal and iron ore as raw materials to reduce iron oxides in a high-temperature molten state, and the slag and iron can be completely separated to obtain carbon-containing molten iron similar to a blast furnace; Stirring and the temperature is very high, generally fluctuating in the temperature range of 1700-1900 ° C. The refractory material is subjected to various mechanical or thermal shocks, such as the scour of high-temperature gas flow, especially thermal shock damage. [0003] In order to solve the technical problems of refractory materials used in smelting reduction furnaces, scholars at home and abroad have conducted research one aft...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the technical problems of refractory materials used in smelting reduction furnaces, scholars at home and abroad have conducted research one after another: as CN101784859B has announced smelting reduction furnaces and refractory materials used therein, the refractory materials are MgO- C bricks; through industrial application, it is found that its existing problems are: in the more representative smelting reduction ironmaking process HIsmelt process, there is a very strong oxidizing atmosphere in the secondary combustion zone, and the damage of carbonaceous materials is faster; and For example, when the magnesia-chrome bricks introduced in the literature are used in smelting reduction furnaces, the foam slag is severe in the final reduction stage, and the slag has a low alkalinity, which is acid slag. The ability of slag erosion is poor

[0004] At present, the refractory material with good slag resistance and can adapt to the aforementioned oxidizing atmosphere and acid slag is mainly Al. 2 o 3 -Cr 2 o 3 Refractory materials, but its thermal shock resistance cannot meet the requirements under such harsh working conditions; and there are generally the following ways to improve the thermal shock resistance of refractory materials: (1) A large number of micropores are set in the material, and the material Under the conditions of high thermal shock resistance and corrosion resistance, this method will be limited; (2) The glass phase in the refractory material softens and plastically deforms at a higher temperature, which can also act like micropores. However, the existence of the glass phase is also detrimental to the high-temperature mechanical properties and corrosion resistance of the refractory material; therefore, the glass phase is always minimized or eliminated in the preparation of the refractory material; (3) Microcrack toughening

[0005] in Al 2 o 3 -Cr 2 o 3 In the use of refractory materials, the chemical composition of the slag usually penetrates into the hot face brick due to the chemical composition gradient at high temperature, and then the metamorphic layer formed on the hot face of the brick is subjected to thermal shock, due to the metamorphic layer, the transition layer and the original brick layer The difference in thermal expansion coefficient causes peeling and damage; the other process is that although it has not been chemically attacked, it will directly cause peeling after being subjected to rapid cooling and rapid heating; the second process above occurs before the aggregate particles are chemically attacked. It is damaged by spalling; so the improvement of Al 2 o 3 -Cr 2 o 3 The thermal shock resistance of refractory materials needs to find another way; US patent document US5053366 announced that adding monoclinic zirconia can improve the high-temperature mechanical properties and thermal shock resistance of refractory materials, but monoclinic zirconia is added in the form of high-purity raw materials, although The thermal shock resistance has been improved, but the sintering condition has become worse, the mechanical strength is low, and the slag resistance of the material has deteriorated accordingly.