Magnesium-carbon gunning mix and preparation method thereof

Abstract

The invention relates to a magnesia-carbon gunning mix which is prepared from the following raw materials in parts by weight: 60-70 parts of magnesite clinker with the particle size of less than or equal to 3mm; 10-30 parts of sintered magnesia powder with the particle size of less than or equal to 1 to 4 parts of 200-mesh flaky graphite; the particle size of the spherical asphalt is less than or equal to 2mm; 0.5-2 parts of a binding agent; 2-5 parts of a plasticizer; and 2-5 parts of an antioxidant. According to the invention, by adjusting the composition of the particle size of the gunning material, the adhesion rate and the washing resistance can be improved; in addition, by adding a proper amount of carbon and asphalt, the wear resistance and erosion resistance can be improved.

Description

Technical Field

[0001] The invention relates to indeterminate refractory materials, in particular to a magnesium-carbon gunning material and a preparation method thereof. Background Art

[0002] The use conditions of molten steel smelting equipment such as converters, electric furnaces, ladles, RH furnaces, etc. are becoming more and more demanding, which are manifested in: high smelting temperature, long smelting time, complex smelting process, damage by alternating hot and cold thermal cycles, increased molten steel circulation volume causing greater erosion and wear on the working lining refractory materials, and changes in smelting steel types causing changes in slag systems, which cause erosion of materials. At present, gunning maintenance of lining materials is one of the important measures to extend service life and reduce refractory consumption.

[0003] The most commonly used gunning material in China is magnesium gunning material, which is characterized by high refractoriness and good resistance to alkaline slag. However, in the application process, its corrosion resistance and erosion resistance need to be improved. Summary of the invention

[0004] In order to overcome the defects of the prior art, the technical problem solved by the present invention is to provide a magnesium-carbon gunning material and a preparation method thereof. The present invention can improve the adhesion rate and erosion resistance by adjusting the composition of the gunning material particle size; and the present invention can also improve the wear resistance and erosion resistance by adding appropriate amounts of carbon and asphalt.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A magnesium-carbon gunning material, wherein the magnesium-carbon gunning material is made of the following raw materials in parts by weight:

[0007]

[0008] The binder is one or a combination of sodium tripolyphosphate, sodium hexametaphosphate or solid water glass, and the particle size of the binder is ≤0.5mm.

[0009] The antioxidant is metal aluminum powder or silicon powder, and the particle size of the antioxidant is ≤0.25 mm.

[0010] The plasticizer is clay or bentonite, and the particle size of the plasticizer is ≤0.5mm.

[0011] The MgO content of the sintered magnesia is ≥92%.

[0012] A method for preparing a magnesium-carbon gunning material, the specific steps are as follows:

[0013] 1) Weigh the ingredients according to the above ratio, add sintered magnesia with a particle size of ≤3 mm and sintered magnesia powder with a particle size of ≤0.074 mm into a mixer and mix for 2 to 3 minutes;

[0014] 2) Add 200 mesh flake graphite and spherical asphalt with a particle size of ≤0.5 mm into the mixer and continue mixing for 2 to 3 minutes;

[0015] 3) Add the binder, plasticizer and antioxidant into the mixer and mix for 3 to 5 minutes to obtain a mixture;

[0016] 4) Screening the mixed material to separate coarse particles, fine particles and fine powder;

[0017] 5) Add the coarse particles, fine particles and fine powder into a mixer in the ratio of (42-45): (20-25): 33, mix for 3-5 minutes and then discharge.

[0018] The particle size of the coarse particles is 0.088-3 mm; the particle size of the fine particles is 0.044-0.088 mm; and the particle size of the fine powder is less than 0.044 mm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1) The present invention adopts sintered magnesia as the main material of the gunning material to improve the resistance of the gunning material to high-temperature smelting erosion and scouring wear; carbon and asphalt are added to the gunning material, so that the gunning material has better volume stability at high temperature, which is beneficial to improving the slag corrosion resistance, thermal shock resistance and spalling resistance; in addition, since the asphalt particle size is large, its heating and carbonization speeds are slow, and the carbonization rate is high, which is beneficial to improving the adhesion of the gunning material.

[0021] 2) The present invention reasonably distributes the particle size of the gunning material so that the gunning material is not easy to rebound during the gunning process, thereby reducing the waste of refractory materials and improving the adhesion rate (higher than 85%) and erosion resistance. DETAILED DESCRIPTION

[0022] The specific implementation mode of the present invention is further described below:

[0023] Example 1

[0024] A magnesium-carbon gunning material, wherein the magnesium-carbon gunning material is made of the following raw materials in parts by weight:

[0025]

[0026] The binder is one or a combination of sodium tripolyphosphate, sodium hexametaphosphate or solid water glass, and the particle size of the binder is ≤0.5mm.

[0027] The antioxidant is metal aluminum powder or silicon powder, and the particle size of the antioxidant is ≤0.25 mm.

[0028] The plasticizer is clay or bentonite, and the particle size of the plasticizer is ≤0.5mm.

[0029] The MgO content of the sintered magnesia is greater than or equal to 92%.

[0030] A method for preparing a magnesium-carbon gunning material, the specific steps are as follows:

[0031] 1) Weigh the ingredients according to the above ratio, add sintered magnesia with a particle size of ≤3 mm and sintered magnesia powder with a particle size of ≤0.074 mm into a mixer and mix for 2 minutes;

[0032] 2) Add 200 mesh flake graphite and spherical asphalt with a particle size of ≤0.5 mm into the mixer and continue mixing for 2 minutes;

[0033] 3) adding a binder, a plasticizer and an antioxidant into a mixer and mixing for 3 minutes to obtain a mixture;

[0034] 4) Screening the mixed material to separate coarse particles, fine particles and fine powder;

[0035] 5) Add coarse particles, fine particles and fine powder into the mixer according to the weight ratio of 43:25:33, mix for 5 minutes, and then discharge. The proportion of fine powder to coarse particles should not be too large. If there is too much fine powder, there will be a lot of dust during gunning, and the fine powder will be lost, which is relatively wasteful; if there are too many coarse particles, the rebound rate of the gunning material will be high and the adhesion rate of the material will be low.

[0036] The particle size of the coarse particles is 0.088-3 mm; the particle size of the fine particles is 0.044-0.088 mm; and the particle size of the fine powder is less than 0.044 mm.

[0037] Example 2

[0038] A magnesium-carbon gunning material, wherein the magnesium-carbon gunning material is made of the following raw materials in parts by weight:

[0039]

[0040] The binder is one or a combination of sodium tripolyphosphate, sodium hexametaphosphate or solid water glass, and the particle size of the binder is ≤0.5mm.

[0041] The antioxidant is metal aluminum powder or silicon powder, and the particle size of the antioxidant is ≤0.25 mm.

[0042] The plasticizer is clay or bentonite, and the particle size of the plasticizer is ≤0.5mm.

[0043] The MgO content of the sintered magnesia is greater than or equal to 92%.

[0044] A method for preparing a magnesium-carbon gunning material, the specific steps are as follows:

[0045] 1) Weigh the ingredients according to the above ratio, add sintered magnesia with a particle size of ≤3 mm and sintered magnesia powder with a particle size of ≤0.074 mm into a mixer and mix for 2 minutes;

[0046] 2) Add 200 mesh flake graphite and spherical asphalt with a particle size of ≤0.5 mm into the mixer and continue mixing for 2 minutes;

[0047] 3) adding a binder, a plasticizer and an antioxidant into a mixer and mixing for 3 minutes to obtain a mixture;

[0048] 4) Screening the mixed material to separate coarse particles, fine particles and fine powder;

[0049] 5) Add the coarse particles, fine particles and fine powder into the mixer in a weight ratio of 42:24:33, mix for 5 minutes and then discharge.

[0050] The particle size of the coarse particles is 0.088-3 mm; the particle size of the fine particles is 0.044-0.088 mm; and the particle size of the fine powder is less than 0.044 mm.

[0051] The preferred embodiments of the present invention are described in detail above, but 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. A magnesium-carbon gunning material, characterized in that: The magnesium-carbon gunning material is made of the following raw materials in parts by weight:

2. A magnesium-carbon gunning material according to claim 1, characterized in that: The binder is one or a combination of sodium tripolyphosphate, sodium hexametaphosphate or solid water glass, and the particle size of the binder is ≤0.5mm.

3. A magnesium-carbon gunning material according to claim 1, characterized in that: The antioxidant is metal aluminum powder or silicon powder, and the particle size of the antioxidant is ≤0.25 mm.

4. A magnesium-carbon gunning material according to claim 1, characterized in that: The plasticizer is clay or bentonite, and the particle size of the plasticizer is ≤0.5mm.

5. The magnesium-carbon gunning material according to claim 1, characterized in that: The MgO content of the sintered magnesia is ≥92%.

6. A method for preparing a magnesium-carbon gunning material according to any one of claims 1 to 5, characterized in that: The specific steps are as follows: 1) Weigh the ingredients according to the above ratio, add sintered magnesia with a particle size of ≤3 mm and sintered magnesia powder with a particle size of ≤0.074 mm into a mixer and mix for 2 to 3 minutes; 2) Add 200 mesh flake graphite and spherical asphalt with a particle size of ≤0.5 mm into the mixer and continue mixing for 2 to 3 minutes; 3) Add the binder, plasticizer and antioxidant into the mixer and mix for 3 to 5 minutes to obtain a mixture; 4) Screening the mixed material to separate coarse particles, fine particles and fine powder; 5) Add the coarse particles, fine particles and fine powder into a mixer in the ratio of (42-45): (20-25): 33, mix for 3-5 minutes, and then discharge.

7. The method for preparing a magnesium-carbon gunning material according to claim 6, characterized in that: The particle size of the coarse particles is 0.088-3 mm; the particle size of the fine particles is 0.044-0.088 mm; and the particle size of the fine powder is less than 0.044 mm.

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