In-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory material and preparation method thereof

Abstract

The invention relates to the technical field of refractory materials, in particular to an in-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory material and a preparation method thereof. The preparation method comprises the following steps: S1, taking fused magnesite fine powder for premixing; s2, metal titanium powder, silicon powder and carbon black are taken and mixed to obtain composite powder; s3, uniformly mixing the fused magnesite aggregate, the fused magnesite fine powder, the composite powder, the aluminum powder, the silicon powder and the phenolic resin, and performing compression molding under high pressure; and S4, drying a sample pressed and formed in the step S3, then performing heat treatment, and finally performing in-situ synthesis to obtain the Ti3SiC2 modified low-carbon MgO-C refractory material. Ti3SiC2 is introduced into the low-carbon magnesia-carbon refractory material in situ, a Ti3SiC2 graphite structure is utilized to replace crystalline flake graphite, the carbon source consumption of the magnesia-carbon refractory material is reduced, greenhouse gas emission is reduced, the magnesia-carbon refractory material has excellent oxidation resistance and slag corrosion resistance, and the oxidation resistance and the slag corrosion resistance of the refractory material are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of refractories, and particularly relates to an in-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory and a preparation method thereof. Background Art

[0002] MgO-C refractories have excellent thermal shock stability and slag resistance, and are widely used in converters, electric furnaces, ladles, slide plates, and secondary refining, etc. However, the following problems exist during their use: 1) After carbon is oxidized during service, pores are formed, which not only reduces the mechanical properties of the refractory but also intensifies the penetration and erosion of the molten slag on the refractory; 2) During the smelting of high-quality clean steel and ultra-low carbon steel, the carbon in the refractory is likely to precipitate into the molten steel, reducing the product quality. Existing technologies mostly use methods such as refining the particle size of the carbon source, surface modification of the carbon source, and adding highly efficient antioxidants to improve its large usage amount and poor antioxidant property, but there are problems such as high cost, limited improvement in antioxidant and slag resistance performance, etc.

[0003] Ti3SiC2 has excellent properties such as a high melting point (about 3000 °C), good mechanical properties, high thermal / electrical conductivity, strong damage resistance, and good self-lubrication. Moreover, it has a structure similar to graphite and excellent properties. Ti3SiC2 can replace graphite when preparing low-carbon refractories for clean steel smelting.

[0004] Recently, researchers have found that additives with excellent properties such as heat shock resistance and high thermal conductivity are particularly effective for low-carbon refractories and can even partially replace flake graphite. For example, Chen et al. introduced MAX phase Ti3SiC2 powder into low-carbon MgO-C refractories and evaluated the effects of single additives Ti3SiC2 and Si powder and their combined addition on the microstructure and properties of MgO-C refractories. In addition, Chen et al. also successfully applied Ti3SiC2 powder to Al2O3-C refractories to partially replace flake graphite, improving the erosion resistance of the materials.

[0005] However, the existing technology first synthesizes Ti3SiC2 powder and then adds it to the refractory, which is a two-step method. There are problems such as difficulty in dispersion when directly introducing it into low-carbon MgO-C refractories. Summary of the Invention

[0006] In order to comprehensively solve the above problems, the present invention in-situ introduces Ti3SiC2 into low-carbon magnesia-carbon refractories. By using the graphite-like structure of Ti3SiC2, the use of flake graphite is replaced, the carbon source usage amount of magnesia-carbon refractories is reduced, greenhouse gas emissions are reduced, and it has excellent antioxidant and slag erosion resistance properties, improving the antioxidant performance and slag erosion resistance performance of the refractory.

[0007] To achieve the above object, a first aspect of the present invention provides a preparation method for in-situ synthesizing Ti3SiC2 modified low-carbon MgO-C refractory materials, including:

[0008] S1: Take fused magnesia fine powder for premixing;

[0009] S2: Take titanium powder, silicon powder, and carbon black and mix them to obtain a composite powder;

[0010] S3: Take fused magnesia aggregate, fused magnesia fine powder, composite powder, aluminum powder, silicon powder, and phenolic resin, mix them evenly, and press them into shape under high pressure;

[0011] S4: Dry the sample pressed into shape in S3, and then perform heat treatment to finally in-situ synthesize Ti3SiC2 modified low-carbon MgO-C refractory materials.

[0012] Preferably, in S2, by mass, 30 parts of titanium powder, 10 parts of silicon powder, and 20 - 25 parts of carbon black are taken and mixed to obtain a composite powder.

[0013] Preferably, in S3, by mass, 70 parts of fused magnesia aggregate, 24 parts of fused magnesia fine powder, 3 parts of composite powder, 1 part of aluminum powder, 2 parts of silicon powder, and 4 parts of phenolic resin.

[0014] Preferably, in S3, the pressure for pressing into shape under high pressure is 100 MPa.

[0015] Preferably, in S4, the drying temperature is 240 °C and the time is 24 h.

[0016] Preferably, in S4, the heat treatment conditions are: holding at 1400 °C for 3 h in a reducing atmosphere.

[0017] A second aspect of the present invention provides a Ti3SiC2 modified low-carbon MgO-C refractory material prepared by the above method.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. By in-situ introducing Ti3SiC2 into the low-carbon magnesia-carbon refractory material, using the graphite-like structure of Ti3SiC2 to replace the use of flake graphite, the carbon source consumption of the magnesia-carbon refractory material is reduced, greenhouse gas emissions are reduced, and it has excellent oxidation resistance and slag erosion resistance, improving the oxidation resistance and slag erosion resistance of the refractory material.

[0020] 2. The creativity of the present invention is to generate Ti3SiC2 in one step inside the refractory material through an in-situ reaction method, solving the problem of its difficult dispersion. At the same time, the one-step method can also save energy consumption, and the in-situ generated Ti3SiC2 will have a better combination with the refractory material, which is more beneficial to optimizing its performance. Description of the Drawings

[0021] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention.

[0022] In the accompanying drawings:

[0023] Figure 1 in which, (a) the morphology of sample M0 prepared using flake graphite as the carbon source after oxidation, (b) the morphology of sample M1 prepared using Ti3SiC2 as the carbon source after oxidation, (c) the oxidation index of M0 and M1;

[0024] Figure 2 in which, (a) the morphology of sample M0 prepared using flake graphite as the carbon source after erosion, (b) the morphology of sample M1 prepared using Ti3SiC2 as the carbon source after erosion, (c) the erosion index of M0 and M1

[0025] Figure 3 is the flow chart of the preparation method of the present invention. Specific Embodiments

[0026] The following Figures 1 - 3 describes the preferred embodiments of the present invention. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0027] Example 1:

[0028] A preparation method of an in-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory material, comprising:

[0029] S1: Take 24 parts of fused magnesia fine powder and premix for 40 min;

[0030] S2: Take 30 parts of metallic titanium powder, 10 parts of silicon powder, and 20 - 25 parts of carbon black by mass, and mix to obtain a composite powder;

[0031] S3: Take 70 parts of fused magnesia aggregate and mix in a mixer for 10 min. Add 4 parts of phenolic resin and continue mixing. After the fused magnesia aggregate is coated with the phenolic resin, add 2 parts of metallic aluminum, 1 part of silicon powder, 3 parts of the composite powder, and 24 parts of fused magnesia fine powder and mix for 15 - 20 min. Press into strip, cylindrical, and crucible specimens under 100 MPa;

[0032] S4: Dry the sample formed in S3 at 240 °C for 24 h, and then carry out buried carbon firing at 1400 °C for 3 h to finally in-situ synthesize the Ti3SiC2 modified low-carbon MgO-C refractory material.

[0033] Example 2:

[0034] Using the method described in Example 1, a Ti3SiC2-modified low-carbon MgO-C refractory material was prepared.

[0035] Control Example:

[0036] Using flake graphite as the carbon source: First, 24 parts of fine magnesite powder were premixed for 40 min and then reserved. Then, 70 parts of fused magnesite aggregate were mixed in a mixer for 10 min. 4 parts of phenolic resin and 3 parts of flake graphite were added and mixing continued. After the aggregate was coated with graphite and phenolic resin, 2 parts of metallic aluminum, 1 part of silicon powder, and 24 parts of fused magnesite fine powder were added and mixed for 15 - 20 min. Strips, cylinders, and crucible specimens were pressed at 100 MPa. The pressed samples were heat-treated at 240 °C for 24 h in a high-temperature oven. The specimens were buried in carbon and fired at 1400 °C for 3 h.

[0037] Experimental Results:

[0038] Figure 1 Among them, (a) the morphology of sample M0 prepared using flake graphite as the carbon source after oxidation, (b) the morphology of sample M1 prepared using Ti3SiC2 as the carbon source after oxidation, (c) the oxidation index of M0 is 64%, and the oxidation index of M1 is 56%;

[0039] Figure 2 Among them, (a) the morphology of sample M0 prepared using flake graphite as the carbon source after erosion, (b) the morphology of sample M1 prepared using Ti3SiC2 as the carbon source after erosion, (c) the erosion index of M0 is 1.5, and the erosion index of M1 is 1.1.

[0040] In addition, the refractory material prepared using flake graphite as the carbon source has a bulk density of 3.0 g / cm 3 , an apparent porosity of 14%, a cold crushing strength of 45 MPa, and a cold bending strength of 6 MPa.

[0041] The refractory material prepared using Ti3SiC2 as the carbon source has a bulk density of 3.2 g / cm 3 , an apparent porosity of 13%, a cold crushing strength of 44 MPa, and a cold bending strength of 6 MPa.

[0042] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of in-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory materials, characterized in that: Including: S1: Premix fused magnesia fine powder; S2: Take titanium powder, silicon powder, and carbon black and mix them to obtain a composite powder; S3: Weigh fused magnesia aggregate, fused magnesia fine powder, composite powder, aluminum powder, silicon powder, and phenolic resin according to mass, mix them evenly, and press them into shape under high pressure; S4: Dry the sample pressed into shape in S3, then conduct heat treatment to finally in-situ synthesize Ti3SiC2 modified low-carbon MgO-C refractory material.

2. The preparation method of an in-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory material according to claim 1, characterized in that: In S2, according to mass parts, 30 parts of titanium powder, 10 parts of silicon powder, and 20 - 25 parts of carbon black are mixed to obtain the composite powder.

3. The preparation method of an in-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory material according to claim 2, characterized in that: In S3, according to mass parts, 70 parts of fused magnesia aggregate, 24 parts of fused magnesia fine powder, 3 parts of composite powder, 1 part of aluminum powder, 2 parts of silicon powder, and 4 parts of phenolic resin.

4. The preparation method of an in-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory according to claim 3, characterized in that: In S3, the pressure for pressing into shape under high pressure is 100 MPa.

5. The preparation method of an in-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory material according to claim 4, characterized in that: In S4, the drying temperature is 240 °C and the time is 24 h.

6. The preparation method of an in-situ synthesized Ti3SiC2 modified low-carbon MgO-C refractory material according to claim 5, characterized in that: In S4, the heat treatment conditions are: keep the temperature at 1400 °C for 3 h in a reducing atmosphere.

7. The Ti3SiC2 modified low-carbon MgO-C refractory material prepared by the method according to any one of claims 1 - 6.

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