Low creep high alumina brick based on electrically fused a-beta corundum brick waste and method of making

Abstract

The application discloses a kind of low creep high alumina brick based on electric smelting a-beta corundum brick waste and a preparation method thereof, belong to high alumina brick technical field.The raw material of the low creep high alumina brick includes the following components by mass percentage: electric smelting a-beta corundum brick waste 20-30%, particle size is 0-3.5mm;85 bauxite particles 20-30%;Andalusite powder 10-20%;Silicon line stone powder 10-20%;Electric smelting corundum powder 0-15%;Guangxi white mud powder 0-15%;Admixture 2-5%, additional dosing.The low creep high alumina brick obtained by the application has good microstructure, stable product quality, high compressive strength, good thermal shock resistance, low creep rate, far superior to similar high alumina brick, greatly improves the performance of low creep high alumina brick, and has important application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high alumina bricks, and particularly relates to a low-creep high alumina brick based on electrically fused a-beta corundum brick waste and a preparation method thereof. BACKGROUND

[0002] The high alumina brick is a kind of refractory material, the main component of which is Al2O3, and the high alumina brick is formed by combining bauxite clinker and clay powder and an additive, and then being sintered at high temperature, and the high alumina brick has the characteristics of high refractoriness, high strength and certain creep. The low-creep high alumina brick has basically the same main components as the high alumina brick, but has better performance, higher strength, better low-creep property and better thermal shock resistance. At present, the low-creep high alumina brick mainly uses bauxite clinker sintered by ordinary bauxite ore as raw material, and the bauxite clinker contains corundum phase, mullite phase, glass phase and other impurity phases, and has complex composition, which has a complex influence on various performances of the material, and the quality is unstable, and it is not easy to prepare the low-creep high alumina brick at 1400 DEG C. Moreover, the resource of the bauxite clinker is decreasing, and the high cost is not conducive to the long-term development of the low-creep high alumina brick. SUMMARY

[0003] The application aims to provide a low-creep high alumina brick based on electrically fused a-beta corundum brick waste and a preparation method thereof, and the low-creep high alumina brick has good microstructure, stable product quality, high compressive strength, good thermal shock resistance and low creep rate, greatly improves the performance of the low-creep high alumina brick, and has important application prospect.

[0004] In order to solve the above technical problems, the application adopts the following technical scheme:

[0005] The application provides a low-creep high alumina brick based on electrically fused a-beta corundum brick waste, and the raw material comprises the following components in percentage by mass:

[0006] The electrically fused a-beta corundum brick waste is 20-30%, and the particle size is 0-3.5 mm;

[0007] The 85 bauxite particles are 20-30%;

[0008] The andalusite powder is 10-20%;

[0009] The sillimanite powder is 10-20%;

[0010] The electrically fused corundum powder is 0-15%;

[0011] The Guangxi white mud powder is 0-15%;

[0012] The additive is 2-5%, and is doped.

[0013] According to the above scheme, the particle size of the 85 bauxite particles is 0-3.5 mm.

[0014] According to the above scheme, the particle size of the andalusite powder is ≤0.075 mm; the particle size of the sillimanite powder is 0-0.2 mm; the particle size of the electrically fused corundum powder is ≤0.075 mm; and the particle size of the Guangxi white clay powder is ≤0.075 mm.

[0015] According to the above scheme, in the electrically fused a-β corundum brick waste, a-Al2O3 and β-Al2O3 crystal phases are dominant. Preferably, a-Al2O3 accounts for 40-50 wt%, and β-Al2O3 accounts for 45-60 wt%.

[0016] According to the above scheme, in the electrically fused a-β corundum brick waste, Al2O3≥93 wt%, Na2O+K2O≤1 wt%, and Fe2O3≤1 wt%.

[0017] According to the above scheme, the electrically fused a-β corundum brick waste is waste generated in the production of electrically fused a-β corundum bricks.

[0018] The electrically fused a-β corundum brick is a high-grade electrically fused refractory material commonly used in glass furnaces for glass production in light industry, building materials, electronics, etc. High-purity calcined alumina (more than 95%) and a small amount of additives (Na2CO3 and Na2B4O7·10H2O) are used. After batching, it is put into a three-phase electric arc furnace and cast after high-temperature smelting at 2300°C or above. It mainly includes a-Al2O3 and β-Al2O3, of which a-Al2O3 accounts for 40-50%, and β-Al2O3 accounts for 45-60%. The two crystal phases are intertwined to form a very dense structure. The material is >95% corundum phase and <1% glass phase, with low impurities, high strength, good corrosion resistance, and high-temperature performance. At the same time, β-Al2O3 has a loose crystal lattice, forming a void structure in the material, which is more flexible than other Al2O3 phases. It can diffuse and absorb the energy of thermal stress, avoiding the rapid increase of absorbed energy due to the dense structure, which leads to the rupture of crystal bonds and the rapid fracture and peeling of the material, thereby improving the thermal shock performance of the product.

[0019] According to the above scheme, the electrically fused a-β corundum brick waste is recycled by the following method: the discarded electrically fused a-β corundum brick in the cutting and polishing process is sorted, separated, and impurities are removed, then it is waterlogged, washed 3-4 times, air-dried, and crushed into particles with a particle size of 0-3.5 mm. Iron removal treatment is carried out during the crushing process. Preferably, the Fe2O3 content is controlled within 1%, which can reduce the phenomenon of excessive melting holes on the surface of the product caused by high iron oxide content in the raw material.

[0020] According to the above scheme, in the 85 bauxite particles, Al2O3≥85 wt%, Fe2O3≤1.5 wt%, and refractoriness≥1800°C.

[0021] According to the above scheme, the 85 bauxite particles are obtained by first grading and selecting and water blocking 2-3 times, and then crushing and grinding after natural air drying.

[0022] According to the above scheme, the andalusite fine powder index is: Al2O3≥55wt%, Fe2O3≤1.5wt%.

[0023] According to the above scheme, the sillimanite fine powder index is: Al2O3≥56wt%, Fe2O3≤1wt%.

[0024] According to the above scheme, the electrically fused corundum fine powder index is: Al2O3≥95wt%, Fe2O3≤0.2wt%.

[0025] According to the above scheme, the Guangxi white mud powder Al2O3≥35wt%, Fe2O3≤1.5wt%. The Guangxi white mud powder has good plasticity, low impurity content, clear white color, and good cohesiveness.

[0026] According to the above scheme, the additive is dextrin or paper pulp.

[0027] According to the above scheme, in the low creep high alumina brick, the electrically fused corundum fine powder is 8-15% by mass percentage; the Guangxi white mud powder is 8-15% by mass percentage.

[0028] A preparation method of the above low creep high alumina brick based on electrically fused a-beta corundum brick waste is provided, comprising the following steps:

[0029] 1) The aggregate electrically fused a-beta corundum brick waste, 85 bauxite particles, and an additive are put into a mixing mill for pre-mixing, and then andalusite fine powder, sillimanite fine powder, electrically fused corundum fine powder, Guangxi white mud powder, and water are added for mixing and kneading, and the mixed mud material is free of mud balls and white material, and can be discharged from the mill;

[0030] 2) The discharged mud material is formed into a semi-finished brick blank, and then dried and sintered, to obtain the low creep high alumina brick based on electrically fused a-beta corundum brick waste.

[0031] According to the above scheme, in step 1), the pre-mixing time is 3-5 min, and the mixing and kneading time is 10-15 min.

[0032] According to the above scheme, in step 1), the amount of water added is 3-4% of the total amount of solid materials.

[0033] According to the above scheme, in step 2), the discharged mud material is formed into a semi-finished brick blank by a friction press.

[0034] According to the above scheme, in step 2), the semi-finished brick blank requires a dense appearance, no cracks, honeycomb, and pitted surface.

[0035] According to the above scheme, in the step 2), the drying process is: treating at 90-180 DEG C for 8-15h.

[0036] According to the above scheme, in the step 2), the sintering process is: sintering at 1460-1480 DEG C for 8-12h.

[0037] The application utilizes the performance of a-alumina and beta-alumina components in the electrically fused a-beta corundum brick waste, uses the electrically fused a-beta corundum brick waste with a particle size of 0-3.5mm as the aggregate part of the material to form a solid corundum phase skeleton. The a-Al2O3 can strengthen the density and strength of the material structure skeleton, the plate-like crystalline organization of the beta-Al2O3 is loose in the crystal lattice, forms the void structure on the material, and is more flexible than other Al2O3 phases. At the same time, the a-Al2O3, mullite phase and the like are further combined to form a structure with staggered and thick structure, a certain gap is formed between the skeleton structures, the energy of the absorbed thermal stress can be diffused and absorbed, a buffer zone is formed, the thermal shock resistance of the material is improved, the absorbed energy is prevented from sharply increasing to cause the crystal bond to break, and the material is prevented from sharply breaking and peeling, and the thermal shock resistance of the material is improved. The electrically fused a-beta corundum brick waste can greatly improve the performance of the aggregate, reduces the amount of glass liquid phase, reduces the amount of liquid phase in the material in the high-temperature state, increases the consistency, and reduces the phase displacement. The whole material forms a structure of corundum phase-mullite phase-liquid phase-other impurity phase, the corundum phase and the mullite phase occupy the dominant part, the strength of the skeleton in the material structure is strengthened, the liquid phase sliding of the material structure matrix part is reduced, at the same time, the large plate-like crystalline form of the beta-Al2O3 strengthens the strength of itself and forms a gap, increases the space for the release of external hard force, and improves the thermal shock resistance.

[0038] The beneficial effects of the application are as follows:

[0039] 1. The application provides a low-creep high-alumina brick based on electrically fused a-beta corundum brick waste, which uses electrically fused a-beta corundum brick waste and 85 bauxite particles as aggregates, further combines with andalusite powder, sillimanite powder, electrically fused corundum powder and Guangxi white clay powder, has the same penetration and synergistic effect between components, a reasonable organizational structure, good microstructure of the obtained low-creep high-alumina brick, stable product quality, high compressive strength and good thermal shock resistance; wherein the compressive strength is not less than 60MP, the creep rate is not higher than 0.6, the bulk density is not less than 2.5, and the thermal shock resistance is not less than 30, which is much better than similar high-alumina bricks, greatly improves the performance of the low-creep high-alumina brick, and has important application prospects.

[0040] 2. The application utilizes electrically fused a-beta corundum brick waste to improve performance, replace part of bauxite, reduce cost, solve the problem of processing and recycling of such industrial waste, effectively alleviate the shortage of existing bauxite resources, and has important environmental protection significance and economic value.

[0041] 3. The application has simple preparation process and low cost, and the obtained high alumina brick has the characteristics of high strength, large bulk density, low creep rate and good thermal shock resistance, and is good in effect when used in blast furnace hot blast furnace and industrial kiln, and has industrial application potential. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the application will be described in detail below in combination with the embodiments of the application. The following implementation cases are only a part of the embodiments of the application, rather than all the implementation cases. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0043] The indexes of the related raw materials in the following embodiments of the application are as follows:

[0044] The electrically fused a-beta corundum brick waste is mainly composed of a-Al2O3 and beta-Al2O3 crystal phases, a-Al2O3 accounts for 40-50wt%, beta-Al2O3 accounts for 45-60wt%, Al2O3 is greater than or equal to 93wt%, Na2O+K2O is less than or equal to 1wt%, Fe2O3 is less than or equal to 1wt%, and the particle size is 0-3.5mm; the electrically fused a-beta corundum brick waste is recycled by the following way: the discarded electrically fused a-beta corundum brick in the cutting and polishing process is selected, separated and impurity-removed, then waterlogged, washed 3-4 times, air-dried, crushed into particles with a particle size of 0-3.5mm, and iron removal treatment is carried out in the crushing and pulverizing process, so that the content of Fe2O3 is controlled within 1%.

[0045] 85 Bauxite particles, Al2O3 is greater than or equal to 85wt%, Fe2O3 is less than or equal to 1.5wt%, refractoriness is greater than or equal to 1800℃, and particle size is 0-3.5mm.

[0046] Andalusite fine powder, Al2O3 is greater than or equal to 55wt%, Fe2O3 is less than or equal to 1.5wt%, and particle size is less than or equal to 0.075mm.

[0047] Sillimanite fine powder, Al2O3 is greater than or equal to 56wt%, Fe2O3 is less than or equal to 1wt%, and particle size is 0-0.2mm.

[0048] Electrically fused corundum fine powder, Al2O3 is greater than or equal to 95wt%, Fe2O3 is less than or equal to 0.2wt%, and particle size is less than or equal to 0.075mm.

[0049] Guangxi white clay powder, Al2O3≥35wt%, Fe2O3≤1.5wt%, particle size ≤0.075mm;

[0050] The admixture is dextrin.

[0051] Example 1

[0052] A low creep high alumina brick based on electrically fused a-beta corundum brick waste is provided, and the raw material components are as follows in terms of mass percentage:

[0053] Electrically fused a-beta corundum brick waste 25wt%, particle size 0-3.5mm;

[0054] 85 bauxite particles 25wt%, particle size 0-3.5mm;

[0055] Andalusite fine powder 16wt%, particle size ≤0.075mm;

[0056] Sillimanite fine powder 14wt%, particle size 0-0.2mm;

[0057] Electrically fused corundum fine powder 10wt%, particle size ≤0.075mm;

[0058] Guangxi white clay powder 10wt%, particle size ≤0.075mm;

[0059] External admixture 3.5%.

[0060] The preparation method of the low creep high alumina brick based on electrically fused a-beta corundum brick waste in this embodiment comprises the following steps:

[0061] Each of the above raw materials is mixed in a strong mixing mill. The aggregate electrically fused a-beta corundum brick waste, 85 bauxite particles, and the admixture are put into the mixing mill for pre-mixing for 4 minutes, and then andalusite fine powder, sillimanite fine powder, electrically fused corundum fine powder, Guangxi white clay powder, and water are added for mixing for 12 minutes. The amount of water added is 3.5% of the mass of all solid materials. The mixed material is in the form of no lumps and white material, and can be discharged from the mill. The discharged material is formed into semi-finished brick blanks by a friction press, and the appearance is required to be dense, without cracks, honeycombs, and pitted surfaces. The semi-finished product is dried at 180℃ for 12 hours, and then fired at 1480℃ for 10 hours to obtain the finished product.

[0062] Example 2

[0063] A low creep high alumina brick based on electrically fused a-beta corundum brick waste is provided, and the raw material components are as follows in terms of mass percentage:

[0064] Electrically fused a-beta corundum brick waste 24wt%, particle size 0-3.5mm;

[0065] 85 bauxite particles 26wt%, particle size 0-3.5mm;

[0066] Andalusite powder 12wt%, particle size ≤0.075mm;

[0067] Leucite powder 15wt%, particle size 0-0.2mm;

[0068] Electrically fused corundum powder 11wt%, particle size ≤0.075mm;

[0069] Guangxi white clay powder 12wt%, particle size ≤0.075mm;

[0070] External additive 3.3%.

[0071] The preparation process refers to example 1.

[0072] Example 3

[0073] A low creep high alumina brick based on electrically fused a-beta corundum brick waste is provided, and the raw material components are as follows in percentage by mass:

[0074] Electrically fused a-beta corundum brick waste 26wt%, particle size 0-3.5mm;

[0075] 85 bauxite particles 26wt%, particle size 0-3.5mm;

[0076] Andalusite powder 16wt%, particle size ≤0.075mm;

[0077] Leucite powder 16wt%, particle size 0-0.2mm;

[0078] Electrically fused corundum powder 11wt%, particle size ≤0.075mm;

[0079] Guangxi white clay powder 5wt%, particle size ≤0.075mm;

[0080] External additive 4%.

[0081] The preparation process refers to example 1.

[0082] Table 1 is a performance index comparison table of the low creep high alumina brick of the traditional brick and the high alumina bricks in examples 1-3.

[0083] Table 1. Performance index comparison table of low creep high alumina brick

[0084]

[0085] As shown in Table 1, the low creep high alumina brick prepared by the examples has lower creep rate, higher compressive strength and better thermal shock resistance than the traditional low creep high alumina brick, greatly improving the performance of the low creep high alumina brick, realizing the resource utilization of waste, reducing the production cost, and being suitable for mass production.

[0086] It is to be understood that all such modifications and variations that can occur to those skilled in the art in the light of the foregoing description are to be considered within the scope of the application as defined in the claims appended hereto.

Claims

1. A low creep high alumina brick based on electrically fused a-β corundum brick scrap, characterized in that, The raw materials of the low-creep high-alumina brick by mass percentage include the following components: 20-30% of fused a-beta corundum brick waste with a particle size of 0-3.5 mm; 85 bauxite particles 20-30%; 10-20% of fine powder of andalusite; 10-20% of fine powder of sillimanite; 8-15% of fine powder of fused corundum; 8-15% of Guangxi white clay powder; 2-5% of admixture, which is doped externally; wherein: In the fused a-beta corundum brick waste, a-Al2O3 and β-Al2O3 crystal phases are dominant; Al2O3≥93wt%, Na2O+K2O≤1wt%, Fe2O3≤1wt%; The fused a-beta corundum brick waste is recycled by the following method: the discarded fused a-beta corundum brick in the cutting and polishing process is sorted and separated, impurities are removed, then it is waterlogged, washed 3-4 times, air-dried, and broken into particles with a particle size of 0-3.5 mm, and iron removal treatment is performed during the breaking and crushing process; The admixture is dextrin or paper pulp.

2. The low creep high alumina brick according to claim 1, wherein The particle size of the 85 bauxite particles is 0-3.5 mm; the particle size of the fine powder of andalusite is ≤0.075 mm; the particle size of the fine powder of sillimanite is 0-0.2 mm; the particle size of the fine powder of fused corundum is ≤0.075 mm; and the particle size of the Guangxi white clay powder is ≤0.075 mm.

3. The low creep high alumina brick of claim 1, wherein, In the 85 bauxite particles, Al2O3≥85wt%, Fe2O3≤1.5wt%, and refractoriness≥1800℃; in the fine powder of andalusite, Al2O3≥55wt%, Fe2O3≤1.5wt%; in the fine powder of sillimanite, Al2O3≥56wt%, Fe2O3≤1wt%; in the fine powder of fused corundum, Al2O3≥95wt%, Fe2O3≤0.2wt%; and in the Guangxi white clay powder, Al2O3≥35wt%, Fe2O3≤1.5wt%.

4. A method for the production of a low creep high alumina brick based on electrically fused a-β corundum brick waste according to any one of claims 1 to 3, characterized in that The method comprises the following steps: 1) Put the aggregate fused a-beta corundum brick waste, 85 bauxite particles, and admixture into a mixing mill for pre-mixing, then add the fine powder of andalusite, the fine powder of sillimanite, the fine powder of fused corundum, the Guangxi white clay powder, and water for mixing and kneading, so that the mixed material is free of lumps and white material, and then the mixing is completed; 2) The mixed material is formed into a semi-finished brick blank, then dried and sintered, and thus the low-creep high-alumina brick based on the fused a-beta corundum brick waste is obtained.

5. The preparation method according to claim 4, characterized in that, In step 1), the pre-mixing time is 3-5 min, and the mixing time is 10-15 min.

6. The preparation method according to claim 4, characterized in that, In step 2), the drying process is carried out at a temperature of 90-180℃ for 8-15h, and the sintering process is carried out at a temperature of 1460-1480℃ for 8-12h.

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