Low carbon magnesia-carbon brick, method for manufacturing the same and use thereof

Abstract

The invention relates to a low-carbon magnesia carbon brick and a making method and application thereof. The low-carbon magnesia carbon brick is characterized in that the low-carbon magnesia carbon brick comprises the following compositions: 15 to 25 percent of 5-3 mm fused magnesia, 20 to 30 percent of 3-1 mm fused magnesia, 20 to 40 percent of fused magnesia which is less than or equal to 1 mm, 1 to 10 percent of fused magnesia which is less than or equal to 75 mu m, 1 to 10 percent of fused magnesia which is less than or equal to 45 mu m, 1 to 5 percent of micronized graphite which is less than or equal to 6 mu m, 1 to 5 percent of 10-100 nm nano-carbon materials, and additives, wherein the additives comprise the following compositions: A, 0.5 to 3 percent of boron carbide powder, and B, 0.5 to 3 percent of metal aluminum powder; the sum of the various compositions is 100 percent; and 3 to 5 percent of binding agent - liquid phenol-formaldehyde resin is added. The compositions are subjected to uniform mixing and brick molding for standby. The low-carbon magnesia carbon brick is applied to the upper part, the middle part and the lower part of a VD ladle or a VOD ladle or an RH vacuum heat treatment device. When the low-carbon magnesia carbon brick is applied to a 50 ton VD ladle, the ladle is subjected to whole-course argon blowing treatment for 50 to 90 minutes; the temperature of purified molten steels is between 1,580 and 1,620 DEG C; the service life of the ladle is 90 furnaces; and the problem of recarburization of the molten steels is avoided.

Description

technical field [0001] The invention relates to a low-carbon magnesia-carbon brick, a production method and its application, more precisely, a low-carbon magnesia-carbon brick for low-carbon steel and ultra-low-carbon clean steel smelting thermal equipment lining the working layer refractory material and its production The method particularly relates to a low-carbon magnesia-carbon brick prepared by gradation of fused magnesia, pre-synthesized fused magnesia-zirconium sand, micronized graphite, metal fine powder, etc., and a preparation method, belonging to the field of refractory materials. Background technique [0002] With the continuous improvement of the market's quality requirements for steel products, the technical level of the modern steel industry must continue to improve. Low-carbon and ultra-low-carbon clean steel has become the focus of development. The secondary refining process mostly uses vacuum, strong stirring, and oxidant injection. method, by improving the...

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Problems solved by technology

In addition, its thermal conductivity is about 15-30W / (m·K), and the heat transfer is fast, resulting in excessively high surface temperature of the furnace shell, poor heat preservation effect, and large heat loss, which affects the normal pouring of molten steel

To sum up, traditional magnesia-carbon bricks can no longer meet the smelting requirements of low-carbon and ultra-low-carbon clean steel. Therefore, the development can meet the requirements of low-carbon and low-carbon refractory materials proposed by modern steelmaking technology and even cement and non-ferrous smelting industries. It is very necessary to replace traditional high-carbon magnesia-carbon bricks and high-performance low-carbon magnesia-chrome bricks with silicon, ultra-low carbon, and chromium-free bricks.

[0004] In the research of low-carbon magnesia-carbon bricks, if the carbon content is simply reduced, the original characteristics of graphite with a large wetting angle with molten steel, high thermal conductivity, small thermal expansion coefficient and low elastic modulus will not be reflected, resulting in The thermal shock resistance stability of low-carbon magnesia-carbon bricks becomes poor; at the same time, because the wetting angle between the working surface of low-carbon magnesia-carbon bricks and the slag decreases, it cannot effectively prevent slag from intruding into the brick structure, resulting in the resistance of magnesia-carbon bricks. Poor slag permeability

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