Ultralow-porosity anti-erosion brick and preparation process thereof

Abstract

The preparation process comprises the following steps: uniformly mixing 80-90 parts by mass of fused mullite, 1-2 parts by mass of modified ZrSiO4 fine powder, 5-8 parts by mass of alpha-Al2O3 fine powder, 2-4 parts by mass of silicon powder, 3-5 parts by mass of aluminum powder and 3-5 parts by mass of mullite microsphere powder, adding 5-8 parts by mass of a binding agent, and uniformly mixing to obtain pug; the preparation process of the mullite microspheres comprises the following steps: mixing bauxite, feldspar and silica powder, adding water, grinding into slurry, carrying out spray drying, sintering, and rapidly cooling after sintering; the pug is sealed and stacked for 12-24 h and then subjected to high-pressure forming, and a blank is obtained; and gradually heating the blank to 120 DEG C, drying for 24-48 hours, and firing and molding. The ultralow-porosity anti-erosion brick is low in porosity and good in anti-erosion performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of refractory bricks, and particularly relates to an ultra-low-porosity erosion-resistant brick and a preparation process thereof. BACKGROUND

[0002] Low-porosity mullite bricks are a kind of high-performance refractory materials, and the core feature thereof is to significantly reduce the apparent porosity of the brick body by special raw material selection and production process, thereby greatly improving the comprehensive performance, especially in terms of erosion resistance, permeability resistance and mechanical strength. The low-porosity mullite bricks are used in glass kilns, hot blast furnaces, blast furnaces, tunnel kilns or hazardous waste rotary kilns, etc. The current low-porosity mullite has a porosity of more than 16%, and the low-porosity clay brick has a porosity of 10%, and under complex working conditions, there is still a serious erosion phenomenon, and after erosion, local unevenness occurs, and the erosion material penetrates into the refractory material, and the service life is about 3 years, and the performance needs to be improved. SUMMARY

[0003] The application aims to provide a preparation process of an ultra-low-porosity erosion-resistant brick, and the prepared ultra-low-porosity erosion-resistant brick has low porosity and good erosion resistance.

[0004] Another object of the application is to provide an ultra-low-porosity erosion-resistant brick.

[0005] In order to achieve the above objects, the technical scheme adopted by the application is as follows:

[0006] The preparation process of the ultra-low-porosity erosion-resistant brick comprises the following steps:

[0007] S1: 80-90 parts by mass of electrically fused mullite, 1-2 parts by mass of modified ZrSiO4 fine powder, 5-8 parts by mass of alpha-Al2O3 fine powder, 2-4 parts by mass of silicon powder, 3-5 parts by mass of aluminum powder, 3-5 parts by mass of mullite microsphere powder are uniformly mixed, 5-8 parts by mass of a binder is added and uniformly mixed to obtain a mud; the preparation process of the mullite microspheres comprises the following steps: bauxite, feldspar and silicon powder are mixed, water is added to grind into a slurry, spray drying is performed, and then sintering is performed, and rapid cooling is performed after the sintering is completed;

[0008] S2: the mud is sealed and stacked for 12-24 hours, and then high-pressure forming is performed to obtain a green body;

[0009] S3: the green body is gradually heated to 120 DEG C, and after drying for 24-48 hours, sintering is performed.

[0010] Further, the preparation method of the modified ZrSiO4 comprises the following steps: mixing ZrSiO4 with Sm2O3 to prepare an initial aqueous solution, dissolving in an oil phase to obtain a microemulsion, mixing the microemulsion with an oil phase mixture of an alkali solution, then magnetically stirring for 12-24h to obtain a mixed microemulsion, and then centrifuging, drying and calcining after heat treatment to obtain the modified ZrSiO4.

[0011] Further, the concentration of ZrSiO4 in the initial aqueous solution is 0.32-0.35kg / L, and the concentration of Sm2O3 is 0.05-0.08kg / L; the alkali solution is a NaOH solution, and the concentration of the NaOH solution is 1.2-1.5mol / L.

[0012] Further, the heat treatment is heating the mixed microemulsion at 80-90℃ for 2-3h, and the calcination is calcining at 750-800℃ for 6-8h.

[0013] Further, the binding agent is an aluminum phosphate solution, and the mass concentration of the aluminum phosphate solution is 15-20%.

[0014] Further, the mass ratio of the coarse aggregate in the electrically fused mullite is 40-50%, the mass ratio of the medium aggregate is 20-30%, and the mass ratio of the fine aggregate is 30-40%, the particle size range of the coarse aggregate is 3-1mm, the particle size range of the medium aggregate is 1-0.1mm, and the particle size of the fine aggregate is less than 0.074mm.

[0015] Further, the preparation process of the mullite microspheres comprises the following steps: mixing 85-90 parts by mass of bauxite, 3-6 parts by mass of feldspar and 1-2 parts by mass of silicon powder, and adding 10-15 parts by mass of water to grind into a slurry.

[0016] Further, the sintering temperature is 1400℃-1450℃, and the time is 1-2h.

[0017] Further, the sintering process is: increasing the temperature to 600℃ at a rate of 20-30℃ / h, increasing the temperature from 600℃ to 1200℃ at a rate of 40-50℃ / h, increasing the temperature from 1200℃ to 1550℃ at a rate of 30-40℃ / h, keeping the temperature for 3-4h, and slowly cooling to below 800℃.

[0018] An ultra-low-porosity erosion-resistant brick prepared by the preparation process of the ultra-low-porosity erosion-resistant brick.

[0019] The beneficial effects of the present application are:

[0020] The super low porosity anti-erosion brick of the present application contains part of glass phase in the mullite microspheres, which is transformed into phase state and filled in the micropores of the mullite during the firing process, thereby reducing the porosity. Meanwhile, the fine powder of alpha-Al2O3 can also be filled in the micropores of the mullite, thereby reducing the porosity.

[0021] The super low porosity anti-erosion brick of the present application has the ZrSiO4 modified by Sm2O3, which forms a relatively dense local structure during the firing process, thereby improving the overall anti-erosion performance of the super low porosity anti-erosion brick.

[0022] The super low porosity anti-erosion brick of the present application adds aluminum powder and silicon powder in the high temperature oxidation environment, which are oxidized to generate silica and aluminum oxide to fill the pores, thereby achieving the purpose of blocking the pores and reducing the porosity. DETAILED DESCRIPTION

[0023] The present application will be further described below in combination with the embodiments of the present application.

[0024] Embodiment 1

[0025] The preparation process of the super low porosity anti-erosion brick of the present embodiment includes the following steps:

[0026] S1: The preparation process of the mullite microspheres includes the following steps: 88 kg of bauxite, 5 kg of feldspar and 1.5 kg of silicon powder are mixed, 12 kg of water is added to grind into a slurry. After spray drying, the inlet temperature of the sintered spray dried product is 400℃, and after the sintering is completed, rapid cooling is performed. The sintering temperature is 1400℃-1450℃, and the time is 1h.

[0027] S2: The preparation method of the modified ZrSiO4 includes the following steps: ZrSiO4 and Sm2O3 are mixed to prepare an initial phase aqueous solution, the concentration of ZrSiO4 in the initial phase aqueous solution is 0.35 kg / L, and the concentration of Sm2O3 is 0.06 kg / L. 10 L of the initial phase aqueous solution is dissolved in 15 L of an oil phase to obtain a microemulsion, the oil phase mixture of the microemulsion and 500 mL of an alkali solution is mixed, the alkali solution is a NaOH solution, and the concentration of the NaOH solution is 1.5 mol / L. Then, magnetic stirring is performed for 24 h to obtain a mixed microemulsion, and after heat treatment, centrifugation, drying and calcination, the modified ZrSiO4 fine powder is obtained, and the separated oil phase can be reused. The heat treatment is heating the mixed microemulsion at 90℃ for 2h, and the calcination is calcining at 800℃ for 7h, and then crushing and sieving through a 400 mesh sieve to obtain the modified ZrSiO4 fine powder.

[0028] S3: 85 kg of electric smelting mullite, 2 kg of modified ZrSiO4 fine powder, 5 kg of α-Al2O3 fine powder, 3 kg of silicon powder, 4 kg of aluminum powder, 4 kg of mullite microsphere powder are mixed uniformly, 6 kg of binder is added and mixed uniformly to obtain a paste. The binder is aluminum phosphate solution, the mass concentration of the aluminum phosphate solution is 18%. Electric smelting mullite: purity > 72% Al2O3, mullite phase content > 90%. The mass ratio of coarse aggregate in the electric smelting mullite is 40-50%, the mass ratio of medium aggregate is 20-30%, and the mass ratio of fine aggregate is 30-40%. The particle size range of coarse aggregate is 3-1 mm, the particle size range of medium aggregate is 1-0.1 mm, and the particle size of fine aggregate is less than 0.074 mm.

[0029] S4: The paste is sealed and stacked for 12 h, and then high-pressure formed to obtain a green body.

[0030] S5: The green body is gradually heated to 120℃, dried for 24 h, and then fired. The firing process is as follows: the temperature is raised to 600℃ at a rate of 20-30℃ / h, raised from 600℃ to 1200℃ at a rate of 40-50℃ / h, raised from 1200℃ to 1550℃ at a rate of 30-40℃ / h, raised from 1550℃ to 1720℃ at a rate of 10-20℃ / h, kept for 3-4 h, and slowly cooled to below 800℃.

[0031] The ultra-low-porosity erosion-resistant brick of the present embodiment is prepared by the preparation process of the ultra-low-porosity erosion-resistant brick of the present embodiment.

[0032] Example 2

[0033] The preparation process of the ultra-low-porosity erosion-resistant brick of the present embodiment comprises the following steps:

[0034] S1: The preparation process of the mullite microspheres comprises the following steps: 85 kg of bauxite, 6 kg of feldspar, and 2 kg of silicon powder are mixed, and 10 kg of water is added to form a slurry. After spray drying, the inlet temperature of the sintered spray-dried material is 300℃, and after sintering, the material is rapidly cooled. The sintering temperature is 1400℃-1450℃, and the time is 2 h.

[0035] S2: the preparation method of the modified ZrSiO4 includes the following steps: mixing ZrSiO4 and Sm2O3 to prepare an initial aqueous solution, the concentration of ZrSiO4 in the initial aqueous solution is 0.32 kg / L, and the concentration of Sm2O3 is 0.08 kg / L. 10 L of the initial aqueous solution is dissolved in 15 L of an oil phase to obtain a microemulsion, and the microemulsion is mixed with an oil phase mixture of 500 mL of an alkali solution, the alkali solution is a NaOH solution, and the concentration of the NaOH solution is 1.2 mol / L. Then, the mixed microemulsion is stirred magnetically for 12 h to obtain a mixed microemulsion, and the mixed microemulsion is heat-treated, centrifuged, dried, and calcined to obtain the modified ZrSiO4, and the separated oil phase can be reused. The heat treatment is heating the mixed microemulsion at 80℃ for 3 h, and the calcination is calcining at 750℃ for 8 h, and then crushing and sieving through a 400 mesh sieve to obtain the modified ZrSiO4 fine powder.

[0036] S3: 90 kg of fused mullite, 1 kg of modified ZrSiO4 fine powder, 6 kg of α-Al2O3 fine powder, 2 kg of silicon powder, 3 kg of aluminum powder, and 3 kg of mullite microsphere powder are uniformly mixed, 5 kg of a binder is added and uniformly mixed to obtain a paste. The binder is an aluminum phosphate solution, and the mass concentration of the aluminum phosphate solution is 15%. The fused mullite has a purity of >72% Al2O3 and a mullite phase content of >90%. The mass ratio of coarse aggregate in the fused mullite is 40-50%, the mass ratio of medium aggregate is 20-30%, and the mass ratio of fine aggregate is 30-40%. The particle size range of the coarse aggregate is 3-1 mm, the particle size range of the medium aggregate is 1-0.1 mm, and the particle size of the fine aggregate is less than 0.074 mm.

[0037] S4: The paste is sealed and stacked for 24 h, and then high-pressure formed to obtain a green body.

[0038] S5: The green body is gradually heated to 120℃, dried for 24-48 h, and then fired. The firing process is as follows: the temperature is raised to 600℃ at a rate of 20-30℃ / h, raised from 600℃ to 1200℃ at a rate of 40-50℃ / h, raised from 1200℃ to 1550℃ at a rate of 30-40℃ / h, raised from 1550℃ to 1720℃ at a rate of 10-20℃ / h, kept at 1720℃ for 3-4 h, and then slowly cooled to below 800℃.

[0039] The ultra-low-porosity erosion-resistant brick of the present embodiment is prepared by the preparation process of the ultra-low-porosity erosion-resistant brick of the present embodiment.

[0040] Example 3

[0041] The preparation process of the ultra-low-porosity erosion-resistant brick of the present embodiment includes the following steps:

[0042] S1: the preparation process of the mullite microspheres includes the following steps: 90 kg of bauxite, 3 kg of feldspar, and 1 kg of silicon powder are mixed, 15 kg of water is added to grind into a slurry. After spray drying, the inlet temperature of sintering the spray-dried product is 500℃, and rapid cooling is performed after sintering is completed. The sintering temperature is 1400℃-1450℃, and the time is 1 h.

[0043] S2: the preparation method of the modified ZrSiO4 includes the following steps: ZrSiO4 is mixed with Sm2O3 to prepare an initial aqueous solution, the concentration of ZrSiO4 in the initial aqueous solution is 0.33 kg / L, and the concentration of Sm2O3 is 0.05 kg / L. 10 L of the initial aqueous solution is dissolved in 15 L of an oil phase to obtain a microemulsion, the microemulsion is mixed with an oil phase mixture of 500 mL of an alkali solution, the alkali solution is a NaOH solution, and the concentration of the NaOH solution is 1.5 mol / L. Then, magnetic stirring is performed for 24 h to obtain a mixed microemulsion, and the mixed microemulsion is heat-treated, centrifuged, dried, and calcined to obtain the modified ZrSiO4 powder. The oil phase after separation can be reused. The heat treatment is heating the mixed microemulsion at 85℃ for 3 h, and the calcination is calcining at 800℃ for 6 h, and then the powder is crushed and sieved through a 400 mesh sieve to obtain the modified ZrSiO4 powder.

[0044] S3: 80 kg of fused mullite, 2 kg of modified ZrSiO4 powder, 8 kg of α-Al2O3 powder, 4 kg of silicon powder, 5 kg of aluminum powder, and 5 kg of mullite microsphere powder are uniformly mixed, 8 kg of a binder is added and uniformly mixed to obtain a paste. The binder is an aluminum phosphate solution, and the mass concentration of the aluminum phosphate solution is 15%. The fused mullite has a purity of >72% Al2O3 and a mullite phase content of >90%. The mass ratio of coarse aggregate in the fused mullite is 40-50%, the mass ratio of medium aggregate is 20-30%, and the mass ratio of fine aggregate is 30-40%. The particle size range of the coarse aggregate is 3-1 mm, the particle size range of the medium aggregate is 1-0.1 mm, and the particle size of the fine aggregate is less than 0.074 mm.

[0045] S4: the paste is sealed and stacked for 24 h, and then high-pressure forming is performed to obtain a green body.

[0046] S5: the green body is gradually heated to 120℃, dried for 24-48 h, and then fired to form a shape. The firing process is as follows: the temperature is increased to 600℃ at a rate of 20-30℃ / h, increased from 600℃ to 1200℃ at a rate of 40-50℃ / h, increased from 1200℃ to 1550℃ at a rate of 30-40℃ / h, maintained for 3-4 h, and then slowly cooled to below 800℃.

[0047] The ultra-low-porosity erosion-resistant brick of the present embodiment is prepared by the preparation process of the ultra-low-porosity erosion-resistant brick of the present embodiment.

[0048] Comparative Example 1

[0049] The preparation process of the ultra-low porosity erosion-resistant brick of the present comparative example is substantially the same as that of Example 1, except that the present comparative example does not add mullite microspheres, and the weight of the missing mullite microspheres is supplemented with electrically fused mullite.

[0050] Comparative Example 2

[0051] The preparation process of the ultra-low porosity erosion-resistant brick of the present comparative example is substantially the same as that of Example 1, except that the present comparative example uses the same mass of ZrSiO4 to replace the modified ZrSiO4.

[0052] Comparative Example 3

[0053] The preparation process of the ultra-low porosity erosion-resistant brick of the present comparative example is substantially the same as that of Example 1, except that the present comparative example does not add modified ZrSiO4.

[0054] Comparative Example 4

[0055] The preparation process of the ultra-low porosity erosion-resistant brick of the present comparative example is substantially the same as that of Example 1, except that the present comparative example does not add silicon powder and aluminum powder.

[0056] Test Example 1

[0057] Thermal shock resistance test: the sample was placed in a resistance furnace, and kept at 1100℃ for 20min, then taken out and rapidly cooled in cold water for 5min, placed in air for 5min, and then placed in a resistance furnace for 5min, and the above process was repeated for 10 times. The thermal shock resistance of the ultra-low porosity erosion-resistant bricks of Example 1 and Comparative Examples 1-4 was determined. The test results are shown in Table 1.

[0058] Test Example 2

[0059] The content of SiO2 in the ultra-low porosity erosion-resistant bricks of Example 1 and Comparative Examples 1-4 was determined. The test results are shown in Table 1.

[0060] Test Example 3

[0061] According to the national standard GB / T 2997-2015 "Test method for volume density, apparent porosity and true porosity of dense shaped refractory products", the porosity and bulk density of the ultra-low porosity erosion-resistant bricks of Example 1 and Comparative Examples 1-4 were determined. The test results are shown in Table 1.

[0062] Table 1 Performance test results of the ultra-low porosity erosion-resistant bricks of Example 1 and Comparative Examples 1-4

[0063]

[0064]

[0065] As can be seen from Table 1, the super-low-porosity erosion-resistant brick prepared by the application has good thermal shock resistance and mechanical properties, can be used in working conditions with large temperature fluctuations, and the super-low-porosity erosion-resistant brick prepared by the application has low porosity, thereby improving the erosion resistance of the super-low-porosity erosion-resistant brick.

Claims

1. A preparation process for ultra-low porosity erosion-resistant bricks, characterized in that, Includes the following steps: S1: Mix 80-90 parts by weight of fused mullite, 1-2 parts by weight of modified ZrSiO4 fine powder, 5-8 parts by weight of α-Al2O3 fine powder, 2-4 parts by weight of silicon powder, 3-5 parts by weight of aluminum powder, and 3-5 parts by weight of mullite microsphere powder evenly, and add 5-8 parts by weight of binder and mix evenly to obtain a slurry; The preparation process of mullite microspheres includes the following steps: mix bauxite, feldspar, and silicon powder, add water and grind into a slurry, spray dry and then sinter, and rapidly cool after sintering; S2: After sealing and piling the clay for 12-24 hours, high pressure molding is performed to obtain the blank; S3: Gradually heat the raw material to 120℃, dry it for 24-48 hours, and then fire it to form the shape.

2. The preparation process of the ultra-low porosity erosion-resistant brick according to claim 1, characterized in that, The preparation method of the modified ZrSiO4 includes the following steps: ZrSiO4 and Sm2O3 are mixed to prepare an initial aqueous solution, which is then dissolved in the oil phase to obtain a microemulsion. The microemulsion is mixed with the oil phase mixture of the alkaline solution, and then magnetically stirred for 12-24 hours to obtain a mixed microemulsion. The mixed microemulsion is then heat-treated, centrifuged, dried, and calcined to obtain the final product.

3. The preparation process of the ultra-low porosity erosion-resistant brick according to claim 2, characterized in that, The initial aqueous solution contains ZrSiO4 at a concentration of 0.32–0.35 kg / L and Sm2O3 at a concentration of 0.05–0.08 kg / L; the alkaline solution is a NaOH solution with a concentration of 1.2–1.5 mol / L.

4. The preparation process of the ultra-low porosity anti-erosion brick according to claim 2, characterized in that, The heat treatment involves heating the mixed microemulsion at 80–90°C for 2–3 hours, and the calcination involves calcining at 750–800°C for 6–8 hours.

5. The preparation process of the ultra-low porosity erosion-resistant brick according to claim 1, characterized in that, The binder is an aluminum phosphate solution with a mass concentration of 15-20%.

6. The preparation process of the ultra-low porosity erosion-resistant brick according to claim 1, characterized in that, The electrofused mullite contains 40-50% coarse aggregate, 20-30% medium aggregate, and 30-40% fine aggregate. The coarse aggregate has a particle size range of 3-1 mm, the medium aggregate has a particle size range of 1-0.1 mm, and the fine aggregate has a particle size of less than 0.074 mm.

7. The preparation process of the ultra-low porosity erosion-resistant brick according to claim 1, characterized in that, The preparation process of the mullite microspheres includes the following steps: mixing 85-90 parts by weight of bauxite, 3-6 parts by weight of feldspar, and 1-2 parts by weight of silica powder, and adding 10-15 parts by weight of water to grind into a slurry.

8. The preparation process of the ultra-low porosity erosion-resistant brick according to claim 1 or 7, characterized in that, The sintering temperature is 1400℃~1450℃, and the time is 1~2h.

9. The preparation process of the ultra-low porosity erosion-resistant brick according to claim 1, characterized in that, The firing process is as follows: the temperature is raised to 600℃ at a heating rate of 20-30℃ / h, raised from 600℃ to 1200℃ at a heating rate of 40-50℃ / h, raised from 1200℃ to 1550℃ at a heating rate of 30-40℃ / h, held at that temperature for 3-4 hours, and then slowly cooled to below 800℃.

10. An ultra-low porosity anti-erosion brick prepared using the preparation process of the ultra-low porosity anti-erosion brick as described in claim 1.

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