High-refractoriness-under-load corundum slurry for blast furnace and preparation method thereof

Abstract

The invention discloses high-refractoriness-under-load corundum slurry for a blast furnace and a preparation method thereof. The refractory material is mainly prepared from the following raw materials in percentage by mass: 60 to 80 percent of 200-mesh white corundum refractory powder, 10 to 30 percent of 200-mesh high-alumina bauxite powder, 0 to 10 percent of 200-mesh andalusite powder, 0 to 10 percent of 200-mesh alumina powder, 1 to 10 percent of 200-mesh 325-mesh silicon carbide powder and 2 to 4 percent of binding clay. In addition, a binding agent accounting for 3-5% of the total weight of the raw materials is added. The preparation method comprises the following steps: premixing andalusite powder, alumina powder, silicon carbide powder, binding clay and a binding agent to obtain premixed powder; and mixing the white corundum refractory powder and the high-alumina bauxite powder, adding the obtained premixed powder, and continuously mixing to obtain the high-refractoriness-under-load corundum slurry. The high-refractoriness-under-load corundum slurry is prepared through a specific raw material combination and process, the high-temperature stability and erosion resistance of the obtained corundum slurry are remarkably improved, and meanwhile the construction performance is improved.

Description

1. Technical field:

[0001] The invention belongs to the technical field of refractory materials, and in particular relates to a high-load soft corundum slurry for a blast furnace and a preparation method thereof. 2. Background technology:

[0002] The functions of refractory slurry include providing good fluidity and plasticity, having the necessary adhesion after construction and hardening to ensure that it is integrated with the masonry or substrate, resisting external forces and gas and slag erosion; having the same or equivalent chemical composition as the masonry or substrate material to avoid chemical reactions between different materials; having similar linear expansion properties to the masonry or substrate material to avoid separation from each other, having a stable volume, and ensuring the integrity and tightness of the masonry and protective layer.

[0003] At present, refractory bricks matched with refractory mud have good high-temperature stability, and the load softening temperature can be greater than 1700℃. However, the refractory mud is not fired at high temperature during construction, and its high-temperature performance is not stable. Since the amount of refractory mud in kiln masonry is only 5%, and its masonry joint is less than 2mm, most construction companies believe that as long as the refractory mud is easy to construct and has the necessary high and low temperature adhesion, it can meet the use requirements, and the load softening performance related to the refractory mud's high-temperature performance is not taken as a test item.

[0004] In fact, since refractory mud is not fired at high temperature during construction, it may have problems such as insufficient thermal stability, insufficient load softening temperature due to shrinkage at high temperature, and strength loss causing mud masonry to collapse and be corroded by slag during use. 3. Summary of the invention:

[0005] The technical problem to be solved by the present invention is: in order to overcome the low-load soft technical problem of existing refractory mud for blast furnaces, the present invention provides a high-load soft corundum mud for blast furnaces and a preparation method thereof. The high-load soft corundum mud of the present invention is prepared by a specific raw material combination and process, and the obtained corundum mud significantly improves the high-temperature stability and corrosion resistance, and at the same time improves the construction performance.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is:

[0007] The invention provides a high-load soft corundum slurry for blast furnace, which is mainly composed of 60-80% of 200-mesh white corundum refractory powder, 10-30% of 200-mesh high-alumina bauxite powder, 0-10% of 200-mesh andalusite powder, 0-10% of 200-mesh alumina powder, 1-10% of 200-325-mesh silicon carbide powder and 2-4% of bonding clay, and in addition, a binder accounting for 3-5% of the total weight of the above-mentioned various raw materials is added.

[0008] According to the above-mentioned high-load soft corundum slurry for blast furnace, the high-load soft corundum slurry is mainly composed of 70-80% of 200-mesh white corundum refractory powder, 10-20% of 200-mesh high-alumina bauxite powder, 5-10% of 200-mesh andalusite powder, 0-10% of 200-325-mesh alumina powder, 3-10% of 200-325-mesh silicon carbide powder and 2-4% of binding clay; in addition, a binder accounting for 3-5% of the total weight of the above-mentioned various raw materials is added.

[0009] According to the above-mentioned high-load soft corundum slurry for blast furnace, the high-load soft corundum slurry is mainly composed of 75-80% of 200-mesh white corundum refractory powder, 10-15% of 200-mesh high-alumina bauxite powder, 5-10% of 200-mesh andalusite powder, 0-5% of 200-325-mesh alumina powder, 3-8% of 200-325-mesh silicon carbide powder and 2-4% of binding clay; in addition, a binder accounting for 3-5% of the total weight of the above-mentioned various raw materials is added.

[0010] According to the above-mentioned high-load soft corundum slurry for blast furnace, the mass percentage of Al2O3 in the white corundum refractory powder is ≥99%, the mass percentage of Fe2O3 is ≤0.2%, and the mass percentage of TiO2 is ≥2.0%.

[0011] According to the above-mentioned high-loaded soft corundum slurry for blast furnace, the mass percentage of Al2O3 in the high-alumina bauxite powder is 88.0%, the mass percentage of Fe2O3 is ≤2.0%, the mass percentage of CaO+MgO% is ≤0.7%, and the mass percentage of R2O is ≤0.4%.

[0012] According to the above-mentioned high-load soft corundum slurry for blast furnace, the mass percentage of Al2O3 in the andalusite powder is ≥57%, the mass percentage of Fe2O3 is ≤1.0%, and the mass percentage of K2O+Na2O is ≤0.5%.

[0013] According to the above-mentioned high-load soft corundum slurry for blast furnace, the mass percentage of Al2O3 in the alumina powder is ≥99%, the mass percentage of Fe2O3 is ≤0.15%, the mass percentage of SiO2 is ≤0.1%, and the mass percentage of Na2O is ≤0.4%.

[0014] According to the above-mentioned high-load soft corundum slurry for blast furnace, the mass percentage of SiC in the silicon carbide powder is ≥97%, and the mass percentage of Fe2O3 is ≤1.0%.

[0015] According to the above-mentioned high-load soft corundum slurry for blast furnace, the mass percentage of Al2O3 in the binding clay is ≥30%, the mass percentage of Fe2O3 is ≤1.5%, the mass percentage of Na2O is ≤0.1%, and the mass percentage of K2O is ≤0.3%; the binding agent is water or aluminum dihydrogen phosphate (specific gravity is 1.4-1.5).

[0016] In addition, a method for preparing high-load soft corundum slurry for blast furnace is provided, the preparation method comprising the following steps:

[0017] a. First, weigh various raw materials according to the raw material ratio of the above-mentioned high-load soft corundum slurry for blast furnace;

[0018] b. Premix the weighed andalusite powder, alumina powder, silicon carbide powder, binding clay and binder for 30 to 40 minutes to obtain a premixed powder;

[0019] c. Then place the white corundum refractory powder and high-alumina bauxite powder in a strong mixer and mix for 2 to 3 minutes, then add them to the premixed powder obtained in step b and mix for 10 to 15 minutes to obtain a high-load soft corundum slurry.

[0020] The high-loaded soft corundum mud of the present invention adopts appropriate inorganic or organic binders to make the mud have good bonding properties. In particular, during the use of the refractory mud, the heat energy in the environment is used to achieve proper sintering to form a structure with gradient characteristics; the inconsistent thermal expansion coefficients of the main material and the additives in the refractory mud under high temperature conditions make the refractory mud produce a stable thermal expansion coefficient under high temperature use conditions, so that the mud as a whole maintains a stable and firm structure. In addition, the refractory mud of the present invention reduces the firing process during the preparation process, saves some labor time, improves the yield rate, and avoids the emission of polluting gases.

[0021] The positive beneficial effects of the present invention are:

[0022] 1. The high-load soft corundum slurry of the present invention uses water as a binder for uniform stirring, does not require high-temperature sintering, has high strength at high temperature, high load softness, high chemical stability, and thermal expansion characteristics matching refractory bricks, and is suitable for refractory materials for blast furnace linings; it can not only shorten the production cycle and reduce costs, but more importantly, reduce the emission of pollutants, which is beneficial to environmental protection. Therefore, the present invention has significant economic and social benefits.

[0023] 2. The high-load soft corundum mud product prepared by the present invention is suitable for strengthening the lining refractory materials of the harsh parts of the blast furnace. When the high-load soft corundum mud product of the present invention is less than 800°C, the mud completely loses water and clay ash to form a preliminary stable structure; at 800-900°C, the low eutectic in the clay reaches the melting point to generate a small amount of liquid phase, the mud begins to shrink for the first time, the porosity decreases, and the density and strength increase; as the temperature increases, the liquid phase begins to generate and enrich inside the mud, destroying the original internal structural strength of the mud; at 800-1100°C, silicon carbide on the surface of the mud is oxidized Reaction, forming silicon dioxide expansion film, improving the surface strength of mud, providing new strength support for mud; at 1150 ~ 1350 ℃, aluminum dihydrogen phosphate binder begins to sinter, forming aluminum dihydrogen phosphate film inside the mud, further providing continuous strength support for mud; at 1350 ~ > 1700 ℃, andalusite undergoes mullite, forming a cross mullite high temperature stable structure inside the mud, improving high temperature strength support and then improving the load softening performance of mud; maintaining the overall strength of refractory materials in the lining of harsh parts of blast furnace, reducing the penetration and scouring damage of corrosive media and molten iron. Therefore, the product of the present invention can effectively extend the service life of blast furnace.

[0024] 3. The high-load soft corundum slurry product prepared by the technical solution of the present invention has a room temperature flexural strength of ≥3MPa, a high temperature (1500°C) flexural strength of ≥10MPa, and a load softening temperature of >1700°C. 4. Specific implementation methods:

[0025] The present invention is further described below in conjunction with embodiments, but the protection scope of the technical solution of the present invention is not limited thereto.

[0026] In the following embodiments, the mass percentage of Al2O3 in the white corundum refractory powder used is ≥99%, the mass percentage of Fe2O3 is ≤0.2%, and the mass percentage of TiO2 is ≥2.0%; the mass percentage of Al2O3 in the high-alumina bauxite powder is 88.0%, the mass percentage of Fe2O3 is ≤2.0%, the mass percentage of CaO+MgO% is ≤0.7%, and the mass percentage of R2O is ≤0.4%; the mass percentage of Al2O3 in the andalusite powder is ≥57%, the mass percentage of Fe2O3 is ≤1.0%, and the mass percentage of K2O+N The mass percentage of a2O is ≤0.5%; the mass percentage of Al2O3 in alumina powder is ≥99%, the mass percentage of Fe2O3 is ≤0.15%, the mass percentage of SiO2 is ≤0.1%, and the mass percentage of Na2O is ≤0.4%; the mass percentage of SiC in silicon carbide powder is ≥97%, and the mass percentage of Fe2O3 is ≤1.0%; the mass percentage of Al2O3 in combined clay is ≥30%, the mass percentage of Fe2O3 is ≤1.5%, the mass percentage of Na2O is ≤0.1%, and the mass percentage of K2O is

[0027] ≤0.3%; the binder is water or aluminum dihydrogen phosphate (specific gravity is 1.4-1.5).

[0028] Embodiment 1:

[0029] The high-loaded soft corundum slurry for blast furnace of the present invention is composed of 70% of 200-mesh white corundum refractory powder, 15% of 200-mesh high-alumina bauxite powder, 5% of 200-mesh andalusite powder, 3% of 200-325-mesh alumina powder, 5% of 200-325-mesh silicon carbide powder and 2% of bonding clay, expressed by weight percentage; in addition, 4% of the total weight of the above-mentioned various raw materials is added as a binder water.

[0030] Embodiment 2:

[0031] The method for preparing high-load soft corundum slurry for blast furnace described in Example 1 of the present invention has the following detailed steps:

[0032] a. First, various raw materials are weighed according to the raw material ratio of the high-load soft corundum slurry for blast furnace described in Example 1;

[0033] b. Premix the weighed andalusite powder, alumina powder, silicon carbide powder, binding clay and binder for 30 minutes to obtain a premixed powder;

[0034] c. Then, the white corundum refractory powder and high-alumina bauxite powder are placed in a strong mixer and mixed for 3 minutes, and then added to the premixed powder obtained in step b and mixed for 15 minutes to obtain a high-load soft corundum slurry.

[0035] The high-load soft corundum slurry prepared in this embodiment has a room-temperature flexural strength of 3.1 MPa, a high-temperature (1500° C.) flexural strength of 10.5 MPa, and a load softening temperature of >1700° C. after testing.

[0036] Embodiment 3:

[0037] The high-loaded soft corundum slurry for blast furnace of the present invention is composed of 70% of 200-mesh white corundum refractory powder, 10% of 200-mesh high-alumina bauxite powder, 10% of 200-mesh andalusite powder, 3% of 200-325-mesh alumina powder, 5% of 200-325-mesh silicon carbide powder and 2% of bonding clay, expressed by weight percentage; in addition, 4% of the total weight of the above-mentioned various raw materials is added as a binder water.

[0038] Embodiment 4:

[0039] The preparation method of high-load soft corundum slurry for blast furnace described in Example 3 of the present invention is the same as that in Example 2.

[0040] The high-load soft corundum slurry prepared in this embodiment has a room-temperature flexural strength of 3.5 MPa, a high-temperature (1500° C.) flexural strength of 11.4 MPa, and a load softening temperature of >1700° C. after testing.

[0041] Embodiment 5:

[0042] The high-loaded soft corundum slurry for blast furnace of the present invention is composed of 73% of 200-mesh white corundum refractory powder, 10% of 200-mesh high-alumina bauxite powder, 10% of 200-mesh andalusite powder, 0% of 200-325-mesh alumina powder, 5% of 200-325-mesh silicon carbide powder and 2% of bonding clay, and in addition, a binder aluminum dihydrogen phosphate solution (specific gravity is 1.4-1.5) accounting for 4% of the total weight of the above-mentioned various raw materials is added.

[0043] Embodiment 6:

[0044] The preparation method of high-load soft corundum slurry for blast furnace described in Example 5 of the present invention is the same as that in Example 2.

[0045] The high-load soft corundum slurry prepared in this embodiment has a room-temperature flexural strength of 4.5 MPa, a high-temperature (1500° C.) flexural strength of 12.2 MPa, and a load softening temperature of >1700° C. after testing.

[0046] Embodiment 7:

[0047] The high-loaded soft corundum slurry for blast furnace of the present invention is composed of 78% of 200-mesh white corundum refractory powder, 10% of 200-mesh high-alumina bauxite powder, 5% of 200-mesh andalusite powder, 0% of 200-325-mesh alumina powder, 5% of 200-325-mesh silicon carbide powder and 2% of bonding clay, expressed by weight percentage; in addition, a binder aluminum dihydrogen phosphate solution (with a specific gravity of 1.4-1.5) accounting for 4% of the total weight of the above-mentioned various raw materials is added.

[0048] Embodiment 8:

[0049] The preparation method of high-load soft corundum slurry for blast furnace described in Example 7 of the present invention is the same as that in Example 2.

[0050] The high-load soft corundum slurry prepared in this embodiment has a room-temperature flexural strength of 5 MPa, a high-temperature (1500° C.) flexural strength of 12.1 MPa, and a load softening temperature of >1700° C. after testing.

Claims

1. A high-load soft corundum slurry for blast furnace, characterized in that: Expressed in terms of mass percentage, the high-loaded soft corundum slurry is mainly composed of 60-80% of 200-mesh white corundum refractory powder, 10-30% of 200-mesh high-alumina bauxite powder, 0-10% of 200-mesh andalusite powder, 0-10% of 200-mesh alumina powder, 1-10% of 200-325-mesh silicon carbide powder and 2-4% of bonding clay; in addition, a binder accounting for 3-5% of the total weight of the above-mentioned raw materials is added.

2. The high-load soft corundum slurry for blast furnace according to claim 1, characterized in that: The high-load soft corundum slurry is mainly composed of 70-80% of 200-mesh white corundum refractory powder, 10-20% of 200-mesh high-alumina bauxite powder, 5-10% of 200-mesh andalusite powder, 0-10% of 200-325-mesh alumina powder, 3-10% of 200-325-mesh silicon carbide powder and 2-4% of bonding clay; in addition, a binder accounting for 3-5% of the total weight of the above-mentioned various raw materials is added.

3. The high-load soft corundum slurry for blast furnace according to claim 1, characterized in that: The high-loaded soft corundum slurry is mainly composed of 75-80% of 200-mesh white corundum refractory powder, 10-15% of 200-mesh high-alumina bauxite powder, 5-10% of 200-mesh andalusite powder, 0-5% of 200-325-mesh alumina powder, 3-8% of 200-325-mesh silicon carbide powder and 2-4% of bonding clay; in addition, a binder accounting for 3-5% of the total weight of the above-mentioned various raw materials is added.

4. The high-load soft corundum slurry for blast furnace according to any one of claims 1 to 3, characterized in that: The mass percentage of Al2O3 in the white corundum refractory powder is ≥99%, the mass percentage of Fe2O3 is ≤0.2%, and the mass percentage of TiO2 is ≥2.0%.

5. The high-load soft corundum slurry for blast furnace according to any one of claims 1 to 3, characterized in that: The mass percentage of Al2O3 in the high-alumina bauxite powder is 88.0%, the mass percentage of Fe2O3 is ≤2.0%, the mass percentage of CaO+MgO% is ≤0.7%, and the mass percentage of R2O is ≤0.4%.

6. The high-load soft corundum slurry for blast furnace according to any one of claims 1 to 3, characterized in that: The mass percentage of Al2O3 in the andalusite powder is ≥57%, the mass percentage of Fe2O3 is ≤1.0%, and the mass percentage of K2O+Na2O is ≤0.5%.

7. The high-load soft corundum slurry for blast furnace according to any one of claims 1 to 3, characterized in that: The mass percentage of Al2O3 in the alumina powder is ≥99%, the mass percentage of Fe2O3 is ≤0.15%, the mass percentage of SiO2 is ≤0.1%, and the mass percentage of Na2O is ≤0.4%.

8. The high-load soft corundum slurry for blast furnace according to any one of claims 1 to 3, characterized in that: The mass percentage of SiC in the silicon carbide powder is ≥97%, and the mass percentage of Fe2O3 is ≤1.0%.

9. The high-load soft corundum slurry for blast furnace according to any one of claims 1 to 3, characterized in that: The mass percentage of Al2O3 in the binding clay is ≥30%, the mass percentage of Fe2O3 is ≤1.5%, the mass percentage of Na2O is ≤0.1%, and the mass percentage of K2O is ≤0.3%; the binding agent is water or aluminum dihydrogen phosphate.

10. A method for preparing high-load soft corundum slurry for blast furnace, characterized in that: The preparation method comprises the following steps: a. First, various raw materials are weighed according to the raw material ratio of the high-load soft corundum slurry for blast furnace according to any one of claims 1 to 3; b. Premix the weighed andalusite powder, alumina powder, silicon carbide powder, binding clay and binder for 30 to 40 minutes to obtain a premixed powder; c. Then place the white corundum refractory powder and high-alumina bauxite powder in a strong mixer and mix for 2 to 3 minutes, then add them to the premixed powder obtained in step b and mix for 10 to 15 minutes to obtain a high-load soft corundum slurry.