Ultralow-carbon magnesia carbon brick with good thermal shock resistance and preparation method thereof

Abstract

The invention relates to the technical field of refractory materials, in particular to an ultralow-carbon magnesia carbon brick with good thermal shock resistance and a preparation method of the ultralow-carbon magnesia carbon brick. The refractory material comprises the following components in parts by weight: 30-42 parts of fused magnesite with the particle size of 1-3mm; 28-35 parts of fused magnesite with a particle size of 0-1 mm; 18-25 parts of fused magnesia with a particle size of less than or equal to 0.088 mm; 3-6 parts of mixed graphite; 8-15 parts of a binding agent; 1-3 parts of silicon powder; and 1-3 parts of aluminum powder. The preparation method comprises the following specific steps: preparing the components according to the ratio, adding the fused magnesia and the binding agent into a stirrer, and stirring; then adding mixed graphite and continuously stirring; finally, adding the silicon powder and the aluminum powder, and continuously stirring; and adding the mixed materials into a mold, carrying out compression molding, and then carrying out heat treatment to obtain the ultralow-carbon magnesia carbon brick. The mixed graphite composed of the crystalline flake graphite and the amorphous graphite is adopted, so that the volume density of the ultralow-carbon magnesia carbon brick is improved, the breaking strength and the thermal shock resistance of the ultralow-carbon magnesia carbon brick at a high temperature are improved, and meanwhile, the slag corrosion resistance and the oxidation resistance of the ultralow-carbon magnesia carbon brick are improved.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials, and in particular to an ultra-low carbon magnesia carbon brick with good thermal shock resistance and a preparation method thereof. Background Art

[0002] Traditional magnesia carbon bricks are a kind of carbon composite refractory material that combines the excellent properties of graphite and magnesia sand. Due to its excellent resistance to slag erosion, thermal shock resistance and high-temperature creep, it is widely used as lining material in high-temperature equipment such as converters and electric furnaces.

[0003] However, due to the high carbon content of traditional magnesia carbon bricks, when used as lining materials for special refining furnaces, it will cause carbon increase problems. However, simply reducing the carbon content in magnesia carbon bricks will affect its key properties such as thermal shock resistance and slag erosion resistance.

[0004] Therefore, with the development of clean steel technology, ultra-low carbon magnesia carbon bricks that require refractory materials to have low carbon content, erosion resistance, good thermal shock stability, and good slag erosion resistance during use have attracted much attention. Summary of the invention

[0005] In order to overcome the defects of the prior art, the technical problem solved by the present invention is to provide an ultra-low carbon magnesium carbon brick with good thermal shock resistance and a preparation method thereof. The ultra-low carbon magnesium carbon brick has good thermal shock resistance and can meet the development requirements of clean steel technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] An ultra-low carbon magnesia carbon brick with good thermal shock resistance comprises the following components in parts by weight:

[0008]

[0009] The MgO content in the fused magnesia is ≥95%.

[0010] The weight ratio of the silicon powder to the aluminum powder is 1:1; the particle size of the aluminum powder is ≤325 mesh; the particle size of the silicon powder is ≤325 mesh.

[0011] The mixed graphite is composed of flake graphite and amorphous graphite, and the weight ratio is 8:2; the C content in the flake graphite is ≥95%, and the particle size of the flake graphite is ≤325 mesh; the C content in the amorphous graphite is ≥97%, and the particle size of the amorphous graphite is ≤200 mesh.

[0012] The binder is solid phenolic resin.

[0013] A method for preparing an ultra-low carbon magnesia carbon brick with good thermal shock resistance, the specific steps are as follows:

[0014] 1) Prepare the components according to the above ratio, add 1-3mm fused magnesia, 0-1mm fused magnesia, ≤0.088mm fused magnesia and binder into a mixer and stir for 3-5 minutes; then add mixed graphite and continue stirring for 3-5 minutes; finally, add silicon powder and aluminum powder and continue stirring for 10-15 minutes;

[0015] 2) Add the mixed materials into a mold, press and shape them, and then perform heat treatment to obtain ultra-low carbon magnesia carbon bricks.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) The present invention adopts mixed graphite composed of flake graphite and amorphous graphite, which is beneficial to improving the volume density of ultra-low carbon magnesium carbon bricks, and can improve the flexural strength and thermal shock stability of ultra-low carbon magnesium carbon bricks at high temperatures, while improving its slag erosion resistance and oxidation resistance.

[0018] 2) The present invention uses aluminum powder and silicon powder as antioxidants for addition. When the magnesium carbon brick is heated, the silicon powder reacts with carbon and oxygen to generate SiO(g) and SiO2(s). The generated SiO2 blocks some pores of the material, effectively improving the antioxidant properties of the magnesium carbon brick. The aluminum powder reacts with C and CO to generate carbides, and re-condenses C, eventually generating high melting point substances such as Al4C3, Al2O3, MA, and then produces volume expansion, making the brick body denser and improving the high temperature strength of the brick. DETAILED DESCRIPTION

[0019] The specific embodiments of the present invention are further described below:

[0020] Example 1

[0021] The present invention provides an ultra-low carbon magnesium carbon brick with good thermal shock resistance, comprising the following components in parts by weight:

[0022]

[0023] The MgO content in the fused magnesia is ≥95%.

[0024] The weight ratio of the silicon powder to the aluminum powder is 1:1; the particle size of the aluminum powder is ≤325 mesh; the particle size of the silicon powder is ≤325 mesh.

[0025] The mixed graphite is composed of flake graphite and amorphous graphite, and the weight ratio is 8:2; the C content in the flake graphite is ≥95%, and the particle size of the flake graphite is ≤325 mesh; the C content in the amorphous graphite is ≥97%, and the particle size of the amorphous graphite is ≤200 mesh.

[0026] The binder is solid phenolic resin.

[0027] A method for preparing an ultra-low carbon magnesia carbon brick with good thermal shock resistance, the specific steps are as follows:

[0028] 1) Prepare the components according to the above ratios, add 1-3mm fused magnesia, 0-1mm fused magnesia, ≤0.088mm fused magnesia and binder into a mixer and stir for 3 minutes; then add mixed graphite and continue stirring for 3 minutes; finally, add silicon powder and aluminum powder and continue stirring for 10 minutes;

[0029] 2) Add the mixed materials into a mold, press and shape them, and then perform heat treatment to obtain ultra-low carbon magnesia carbon bricks.

[0030] Example 2

[0031] The present invention provides an ultra-low carbon magnesium carbon brick with good thermal shock resistance, comprising the following components in parts by weight:

[0032]

[0033] The MgO content in the fused magnesia is ≥95%.

[0034] The weight ratio of the silicon powder to the aluminum powder is 1:1; the particle size of the aluminum powder is ≤325 mesh; the particle size of the silicon powder is ≤325 mesh.

[0035] The mixed graphite is composed of flake graphite and amorphous graphite, and the weight ratio is 8:2; the C content in the flake graphite is ≥95%, and the particle size of the flake graphite is ≤325 mesh; the C content in the amorphous graphite is ≥97%, and the particle size of the amorphous graphite is ≤200 mesh.

[0036] The binder is solid phenolic resin.

[0037] A method for preparing an ultra-low carbon magnesia carbon brick with good thermal shock resistance, the specific steps are as follows:

[0038] 1) Prepare the components according to the above ratios, add 1-3mm fused magnesia, 0-1mm fused magnesia, ≤0.088mm fused magnesia and binder into a mixer and stir for 5 minutes; then add mixed graphite and continue stirring for 5 minutes; finally, add silicon powder and aluminum powder and continue stirring for 14 minutes;

[0039] 2) Add the mixed materials into a mold, press and shape them, and then perform heat treatment to obtain ultra-low carbon magnesia carbon bricks.

[0040] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. In addition, the various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. An ultra-low carbon magnesia carbon brick with good thermal shock resistance, characterized in that: Contains the following components in parts by weight:

2. The ultra-low carbon magnesia carbon brick with good thermal shock resistance according to claim 1, characterized in that: The MgO content in the fused magnesia is ≥95%.

3. The ultra-low carbon magnesia carbon brick with good thermal shock resistance according to claim 1, characterized in that: The weight ratio of the silicon powder to the aluminum powder is 1:1; the particle size of the aluminum powder is ≤325 mesh; the particle size of the silicon powder is ≤325 mesh.

4. The ultra-low carbon magnesia carbon brick with good thermal shock resistance according to claim 1, characterized in that: The mixed graphite is composed of flake graphite and amorphous graphite, and the weight ratio is 8:2; the C content in the flake graphite is ≥95%, and the particle size of the flake graphite is ≤325 mesh; the C content in the amorphous graphite is ≥97%, and the particle size of the amorphous graphite is ≤200 mesh.

5. The ultra-low carbon magnesia carbon brick with good thermal shock resistance according to claim 1, characterized in that: The binder is solid phenolic resin.

6. A method for preparing an ultra-low carbon magnesia carbon brick with good thermal shock resistance as claimed in claim 1, characterized in that: The specific steps are as follows: 1) Prepare the components according to the above ratio, add 1-3mm fused magnesia, 0-1mm fused magnesia, ≤0.088mm fused magnesia and binder into a mixer and stir for 3-5 minutes; then add mixed graphite and continue stirring for 3-5 minutes; finally, add silicon powder and aluminum powder and continue stirring for 10-15 minutes; 2) Add the mixed materials into a mold, press and shape them, and then perform heat treatment to obtain ultra-low carbon magnesia carbon bricks.

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