MgO-Al2O3-ZrO2 refractory material and preparation method thereof
By introducing alumina-magnesia-coated zirconia particles and alumina-zirconia sol binder into magnesium aluminum spinel materials, a core-shell structure and gradient bonding phase are formed, which solves the problem of poor high-temperature mechanical properties and erosion resistance of magnesium aluminum spinel materials. This results in high-strength, thermal shock resistant and erosion resistant refractory materials suitable for iron and steel smelting and non-ferrous metal smelting.
Patent Information
- Application Number
- CN202511615160.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-06
- Publication Date
- 2026-01-20
AI Technical Summary
Existing magnesium aluminum spinel materials have poor high-temperature mechanical properties and corrosion resistance. Furthermore, the addition of ZrO2 causes a mismatch between volume expansion and thermal expansion coefficient due to crystal transformation, which limits their application in steel and non-ferrous metal smelting.
Zirconia particles were coated with a slurry composed of lightly calcined magnesia, boehmite, and talc to form a core-shell structure with magnesia as the shell and zirconia as the core. Alumina-zirconia sol was used as a binder to prepare MgO-Al2O3-ZrO2 refractory material. The gradient bonding phase was formed by sintering to improve the strength and thermal shock resistance of the material.
It improves the material's mechanical properties at room temperature and high temperature, as well as its resistance to thermal shock and corrosion, reduces alloy contamination, and meets the requirements for clean alloy smelting.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of high-temperature ceramics and refractory materials, and particularly relates to a MgO-Al2O3-ZrO2 refractory material and a preparation method thereof. BACKGROUND
[0002] The development and application of magnesium aluminate spinel play an important role in replacing traditional chromium-containing refractory materials, especially in solving the problem of carcinogenic risk caused by traditional chromium-containing refractory materials. 6+ Magnesium aluminate spinel material has excellent thermal shock resistance and chemical stability, and particularly its application in the fields of medium-frequency furnace linings and lithium battery crucibles has become one of the chromium-free refractory materials that are concerned. However, the high-temperature mechanical properties and erosion resistance of magnesium aluminate spinel material are poor, which limits its application in steel smelting and non-ferrous metal smelting, especially the smelting of high-temperature alloys which has higher requirements for cleanliness. Therefore, high-erosion-resistant magnesium aluminate spinel material has become a research hotspot in recent years.
[0003] In the modification research of magnesium aluminate spinel material, some technologies attempt to optimize the performance by adding zircon corundum, which can form a MgO-Al2O3-ZrO2 ternary eutectic structure and thus prevent slag erosion to a certain extent. However, ZrO2 can only be combined with corundum, and its role has obvious limitations. Another technology selects adding zircon to improve the performance of magnesium aluminate spinel material. However, during the preparation and service of the material, zircon will react with MgO and Al2O3 in the material to generate cordierite (formed by the reaction of MgO-Al2O3-SiO2) and mullite (formed by the reaction of Al2O3-SiO2), which will adversely affect the high-temperature service performance of the material. The technology of directly adding ZrO2 cannot overcome the problems of volume expansion caused by ZrO2 crystal transformation and poor thermal shock resistance caused by the mismatch of the thermal expansion coefficients of ZrO2 and other materials. SUMMARY
[0004] The technical problem to be solved by the present application is to provide a MgO-Al2O3-ZrO2 refractory material and a preparation method thereof, which have excellent normal and high-temperature mechanical properties, excellent thermal shock resistance and erosion resistance, a wide range of applications, and low alloy contamination, and can fully meet the use requirements of clean alloy smelting.
[0005] To solve the technical problems proposed in the present application, the present application provides a MgO-Al2O3-ZrO2 refractory material, comprising the following mass percentage of raw materials: 10-25% of fused white corundum particles, 10-30% of fused magnesia particles, 14-26% of magnesia micropowder, 5-10% of alumina micropowder, 20-35% of alumina-magnesia co-coated zirconia particles with a particle size of 1-2 mm, 20-35% of alumina-magnesia co-coated zirconia particles with a particle size of 2-3 mm, and 2-5% of the total mass of the above-mentioned raw materials of a binder.
[0006] Preferably, the refractory material comprises the following mass percentage of raw materials: 10-15% of fused white corundum particles, 10-15% of fused magnesia particles, 14-18% of magnesia micropowder, 5-7% of alumina micropowder, 20-26% of alumina-magnesia co-coated zirconia particles with a particle size of 1-2 mm, 25-35% of alumina-magnesia co-coated zirconia particles with a particle size of 2-3 mm, and 3-5% of the total mass of the above-mentioned raw materials of a binder.
[0007] In the above scheme, the Al2O3 content of the fused white corundum particles is ≥99.4wt%, and the particle size is ≤1mm.
[0008] In the above scheme, the MgO content of the fused magnesia particles is ≥97.8wt%, and the particle size is ≤1mm.
[0009] In the above scheme, the MgO content of the magnesia micropowder is ≥97.8wt%, and the particle size is ≤70μm.
[0010] In the above scheme, the Al2O3 content of the alumina micropowder is ≥99.6wt%, and the particle size is ≤70μm.
[0011] In the above scheme, the preparation of the alumina-magnesia co-coated zirconia particles comprises the following steps: 1) Ball milling is performed on the mixed powder of light-burned magnesia powder, pseudo-boehmite powder and talc powder by adding water, to obtain a ball milling slurry; 2) The zirconia particles are placed in a granulator, and the ball milling slurry is sprayed to prepare granulated particles; 3) The granulated particles are calcined and sieved to obtain alumina-magnesia co-coated zirconia particles with two particle sizes.
[0012] Further, the MgO content of the light-burned magnesia powder is ≥99.5wt%, and the particle size is ≤10μm.
[0013] Further, the impurity content of the pseudo-boehmite powder is less than 1000ppm, and the particle size is ≤10μm.
[0014] Further, the whiteness of the talc powder is ≥90%, and the particle size is ≤10μm.
[0015] Further, the ZrO2 content of the zirconia particles is ≥99.8wt%, and the particle size is 0.5-3mm.
[0016] Further, the mixed powder comprises the following components with the following mass percentage contents: light-burned magnesium oxide micro powder 47-78%, pseudo-boehmite micro powder 15-45%, and talc powder 6-16%.
[0017] Further, the added amount of water is 90-150% of the mass of the mixed powder.
[0018] Further, the ball milling rotation speed is 500-1000r / min, and the ball milling time is 60-180min.
[0019] Further, the spraying amount of the ball milling slurry is 10-20% of the mass of the zirconia particles.
[0020] Further, the calcination temperature is 200-500℃, and the holding time is 3-6h.
[0021] In the above scheme, the binding agent is an alumina-zirconia sol, the solid content is 20-30%, the mass ratio of alumina to zirconia is 1:(0.5-2), and the pH value is 1-3.
[0022] The application further provides a preparation method of the MgO-Al2O3-ZrO2 refractory material. 1) After uniformly stirring raw materials except the binding agent, the binding agent is added and uniformly mixed to obtain mixed mud; 2) After the mixed mud is pressed into a blank and dried, sintering is performed to obtain the MgO-Al2O3-ZrO2 refractory material.
[0023] In the above scheme, the pressing pressure is 80-120MPa.
[0024] In the above scheme, the drying temperature is 80-110℃, and the drying time is 24-36h.
[0025] In the above scheme, the sintering temperature is 1600-1750℃, and the holding time is 3-6h.
[0026] Compared with the prior art, the application has the following beneficial effects: 1、The present application uses light-burned magnesium oxide, pseudo-boehmite and talc to coat zirconia particles to form a core-shell structure particle with alumina-magnesia shell and zirconia particle core. When introduced into refractory materials, part of the light-burned magnesium oxide enters the zirconia particles to form magnesium oxide stabilized zirconia under subsequent sintering process, which can slow down the volume expansion of zirconia due to crystal transformation, so that the material has high strength and thermal shock resistance at room temperature and high temperature; the remaining part of the light-burned magnesium oxide reacts with the pseudo-boehmite and talc to form microcrystalline alumina and magnesium aluminate spinel, further improving the strength and thermal shock resistance of the material, while maintaining the core-shell structure to prevent the magnesium oxide in the magnesium stabilized zirconia from dissolving out; then using alumina-zirconia sol as a binder, a magnesium oxide stabilized zirconia-microcrystalline alumina & magnesium aluminate spinel-corundum / magnesia gradient bonding phase is formed between the matrix and aggregate, not only realizing the dispersion distribution of zirconia in the material, but also improving the thermal shock resistance of the material while enhancing and toughening, and the combination between the matrix and aggregate through the core-shell structure has the characteristics of high bonding strength and gradient distribution of composition and organization, which can reduce the porosity and weaken the cracking between the aggregate and matrix due to the mismatch of thermal expansion coefficient under thermal shock environment, has the characteristics of high chemical stability, not easy to react with alloy melt, and not easy to be eroded, and can reduce the generation of inclusions in the alloy smelting process. Thus, the present application has high strength, excellent thermal shock resistance and corrosion resistance, and small alloy pollution, meeting the use requirements of clean alloy smelting.
[0027] 2、The present application adds light-burned magnesium oxide powder, pseudo-boehmite powder and talc powder according to a specific ratio to a proper amount of water for ball milling, which can fully utilize the mutual gelation of pseudo-boehmite and talc, so that the light-burned magnesium oxide, pseudo-boehmite and talc are fully mixed and connected under the dual action of intermolecular attraction and ball milling, and the ball-milled slurry has the characteristics of uniform composition and easy adhesion, so that it can be uniformly and firmly attached to the surface of zirconia particles during the granulation process of zirconia particles; then through preliminary calcination, the light-burned magnesium oxide-pseudo-boehmite-talc mixed slurry is bridged by molecular bonds through hydration and mutual reaction, thereby generating strength to prevent the core-shell structure from being damaged during subsequent mixing and pressing process, and under this treatment condition, the specific particle size of light-burned magnesium oxide and its hydration properties can make it closely combined with zirconia. Thus, the alumina-magnesia co-coated zirconia particles can stably play a role in the system of the present application. DETAILED DESCRIPTION
[0028] In order to better understand the present application, the following examples further illustrate the content of the present application, but the content of the present application is not limited to the following examples.
[0029] The raw materials used in the following examples and comparative examples include: fused white corundum particles, Al2O3 content ≥ 99.4wt%, particle size ≤ 1mm; fused magnesia particles, MgO content ≥ 97.8wt%, particle size ≤ 1mm; magnesia powder, MgO content ≥ 97.8wt%, particle size ≤ 70μm; alumina powder, Al2O3 content ≥ 99.6wt%, particle size ≤ 70μm; light-burned magnesia powder, MgO content ≥ 99.5wt%, particle size ≤ 10μm; pseudo-boehmite powder, impurity content less than 1000ppm, particle size ≤ 10μm; talc powder, whiteness ≥ 90%, particle size ≤ 10μm; zirconia particles, ZrO2 content ≥ 99.8wt%, particle size 0.5-3mm.
[0030] Example 1 A MgO-Al2O3-ZrO2 refractory material, comprising the following mass percentage of raw materials: 25% of fused white corundum particles, 10% of fused magnesia particles, 14% of magnesia powder, 10% of alumina powder, 20% of alumina-magnesia co-coated zirconia particles with particle size 1-2mm, 21% of alumina-magnesia co-coated zirconia particles with particle size 2-3mm, plus 2% of the total mass of the above raw materials of a binder. Wherein: The binder is an alumina-zirconia sol with solid content of 20%, mass ratio of alumina to zirconia of 1:0.5, and pH value of 1, which is mixed from commercially available alumina sol and zirconia sol.
[0031] The preparation of alumina-magnesia co-coated zirconia particles includes the following steps: 1) To the mixed powder containing 78wt% of light-burned magnesia powder, 15wt% of pseudo-boehmite powder and 7wt% of talc powder, plus 150wt% of water of the mixed powder, ball mill for 60min at a speed of 500r / min to obtain a ball milling slurry; 2) Put the zirconia particles into a granulator, spray the above ball milling slurry, the spraying amount of the ball milling slurry is 10% of the mass of the zirconia particles, to obtain granulated particles; 3) Put the granulated particles into a muffle furnace and heat to 200℃ for 3h, then sieve after natural cooling, to obtain alumina-magnesia co-coated zirconia particles with particle size 1-2mm and 2-3mm.
[0032] The preparation method of the MgO-Al2O3-ZrO2 refractory material of this example includes the following steps: 1) After the fused white corundum particles, the fused magnesia particles, the magnesia powder, the alumina powder, the alumina-magnesia co-coated zirconia particles with particle size 1-2mm and the alumina-magnesia co-coated zirconia particles with particle size 2-3mm are stirred uniformly, plus the binder to mix uniformly, a mixed mud is obtained; 2) The above mixing material is pressed into a green body by a press at a pressure of 80 MPa, dried at 80℃ for 36 h, and sintered at 1600℃ for 3 h to obtain the MgO-Al2O3-ZrO2 refractory material.
[0033] Example 2 A MgO-Al2O3-ZrO2 refractory material includes the following raw materials in the following mass percentages: 10% of fused white corundum particles, 10% of fused magnesia particles, 14% of magnesia micropowder, 5% of alumina micropowder, 26% of alumina-magnesia co-coated zirconia particles with a particle size of 1-2 mm, 35% of alumina-magnesia co-coated zirconia particles with a particle size of 2-3 mm, and 5% of the total mass of the above raw materials of a binder. Wherein: The binder is an alumina-zirconia sol with a solid content of 30%, a mass ratio of alumina to zirconia of 1:2, and a pH value of 3, which is a mixture of commercially available alumina sol and zirconia sol.
[0034] The preparation of the alumina-magnesia co-coated zirconia particles includes the following steps: 1) A mixture of light-burned magnesia powder 47wt%, pseudo-boehmite powder 45wt% and talc powder 8wt% is added with 90wt% of water of the mixture to ball mill at a speed of 1000 r / min for 180 min to obtain a ball milling slurry; 2) The zirconia particles are placed in a granulator and the above ball milling slurry is sprayed on the zirconia particles at a spraying amount of 20% of the mass of the zirconia particles to obtain granulated particles; 3) The granulated particles are heated to 500℃ in a muffle furnace for 6 h, and after natural cooling, the alumina-magnesia co-coated zirconia particles with a particle size of 1-2 mm and 2-3 mm are obtained by sieving.
[0035] The preparation method of the MgO-Al2O3-ZrO2 refractory material of this embodiment includes the following steps: 1) The fused white corundum particles, the fused magnesia particles, the magnesia micropowder, the alumina micropowder, the alumina-magnesia co-coated zirconia particles with a particle size of 1-2 mm, and the alumina-magnesia co-coated zirconia particles with a particle size of 2-3 mm are stirred uniformly, and then a binder is added and mixed uniformly to obtain a mixing material; 2) The above mixing material is pressed into a green body by a press at a pressure of 20 MPa, dried at 110℃ for 24 h, and sintered at 1750℃ for 6 h to obtain the MgO-Al2O3-ZrO2 refractory material.
[0036] Example 3 The MgO-Al2O3-ZrO2 refractory material comprises raw materials with the following mass percentage: 15% of fused white corundum particles, 15% of fused magnesia particles, 18% of magnesia micropowder, 7% of alumina micropowder, 20% of alumina-magnesia co-coated zirconia particles with a particle size of 1-2 mm, 25% of alumina-magnesia co-coated zirconia particles with a particle size of 2-3 mm, and 3% of the total mass of the above raw materials of a binding agent. The binding agent is an alumina-zirconia sol with a solid content of 25%, a mass ratio of alumina to zirconia of 1:1, and a pH value of 2, which is mixed from a commercially available alumina sol and a zirconia sol.
[0037] The preparation of the alumina-magnesia co-coated zirconia particles comprises the following steps: 1) A mixed powder containing 50 wt% of light-burned magnesia powder, 35 wt% of pseudo-boehmite powder, and 15 wt% of talc powder is mixed with 120 wt% of water added thereto, and then ball-milled at a rotation speed of 800 r / min for 100 min to obtain a ball-milling slurry; 2) The zirconia particles are placed in a granulator, and the ball-milling slurry is sprayed thereon at a spraying amount of 15% of the mass of the zirconia particles to obtain granulated particles; 3) The granulated particles are heated to 400℃ in a muffle furnace for 5 h, and then sieved after natural cooling to obtain alumina-magnesia co-coated zirconia particles with a particle size of 1-2 mm and 2-3 mm.
[0038] The preparation method of the MgO-Al2O3-ZrO2 refractory material in the embodiment comprises the following steps: 1) The fused white corundum particles, the fused magnesia particles, the magnesia micropowder, the alumina micropowder, the alumina-magnesia co-coated zirconia particles with a particle size of 1-2 mm, and the alumina-magnesia co-coated zirconia particles with a particle size of 2-3 mm are uniformly stirred, and then a binding agent is added and uniformly mixed to obtain a mixed slurry; 2) The mixed slurry is pressed into a green body by a press at a pressure of 100 MPa, dried at 100℃ for 30 h, and then sintered at 1650℃ for 4 h to obtain the MgO-Al2O3-ZrO2 refractory material.
[0039] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that, in the preparation process of the alumina-magnesia co-coated zirconia particles, no ball-milling is performed, and the slurry obtained by uniformly mixing the mixed powder and water in step 1) is used for subsequent coating.
[0040] Comparative Example 2 Comparative Example 2 differs from Example 2 only in that the preparation process of the alumina-magnesia co-coated zirconia particles does not include granulation, and the particles obtained by mixing the zirconia particles with the ball milling slurry in Step 2) are used for subsequent calcination.
[0041] Comparative Example 3 Comparative Example 3 differs from Example 2 only in that uncoated zirconia particles are directly used, and the particle size of the alumina-magnesia co-coated zirconia particles is replaced by zirconia particles with a particle size of 1-2 mm, and the particle size of the alumina-magnesia co-coated zirconia particles is replaced by zirconia particles with a particle size of 2-3 mm.
[0042] Comparative Example 4 Comparative Example 4 differs from Example 2 only in that the binder is replaced by a PVA solution with a concentration of 5 wt%, and the alumina-magnesia co-coated zirconia particles are replaced by magnesia-coated zirconia particles (the mixed powder in the preparation process is replaced by single light-burned magnesia powder).
[0043] The performance of the MgO-Al2O3-ZrO2 refractory materials prepared in each example and each comparative example was tested, wherein the thermal shock strength retention rate was 1100°C water cooling for 5 times, and the alloy oxygen content could reflect the reaction degree of the refractory material with the alloy, and then reflect the corrosion resistance of the refractory material, and the test results are shown in Table 1.
[0044] Table 1
[0045] As can be seen from Table 1, the refractory prepared in the embodiment of the application has high strength, excellent thermal shock resistance and erosion resistance, and small alloy contamination, and meets the use requirements of clean alloy melting. In Comparative Example 1, because ball milling is not performed, the coating slurry is not uniformly mixed, the uniform distribution of MgO-Al2O3 composite combined phase and the effect of MgO stabilizing ZrO2 cannot be achieved, and thus the comprehensive performance is poor, and in particular, the strength is significantly reduced. In Comparative Example 2, because granulation is not performed, the prepared alumina-magnesia coated zirconia particles have problems such as uneven thickness of the coating layer, loose structure of the coating layer, and uneven distribution, and thus the prepared MgO-Al2O3-ZrO2 refractory has low strength, poor thermal shock resistance and poor erosion resistance. In Comparative Example 3, because pre-coating is not performed, the core-shell structure cannot be formed, and thus there is no gradient structure from aggregate to fine powder, which affects the strength, the thermal expansion coefficient of the material is high, and thus the thermal shock resistance and the erosion resistance are poor. In Comparative Example 4, because only magnesia is used to coat zirconia, only the magnesia stabilizes the zirconia, and there is no microcrystalline alumina and magnesia-alumina spinel structure, and no alumina-zirconia sol is used as a binder, and thus the strength, the thermal shock resistance and the erosion resistance are poor.
[0046] The above examples are merely intended for clear illustration, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art, and it is not necessary or possible to exhaust all the embodiments, and thus the obvious changes or variations still fall within the protection scope of the present application.
Claims
1. A MgO-Al2O3-ZrO2 refractory material, characterized in that, Raw materials including the following mass percentage contents: 10-25% of fused white corundum particles, 10-30% of fused magnesia particles, 14-26% of magnesia micro powder, 5-10% of alumina micro powder, 20-35% of alumina-magnesia co-coated zirconia particles with a particle size of 1-2mm, 20-35% of alumina-magnesia co-coated zirconia particles with a particle size of 2-3mm, plus 2-5% of the total mass of the above raw materials of a binding agent.
2. The MgO-Al2O3-ZrO2 refractory material according to claim 1, characterized in that, The preparation of the alumina-magnesia co-coated zirconia particles includes the following steps: 1) adding water to the mixed powder of light-burned magnesia powder, pseudo-boehmite powder and talc powder for ball milling to obtain a ball milling slurry; 2) placing zirconia particles in a granulator, spraying the ball milling slurry to prepare granulated particles; 3) calcining the granulated particles, and sieving to obtain alumina-magnesia co-coated zirconia particles with two particle sizes.
3. The MgO-Al2O3-ZrO2 refractory material according to claim 2, characterized in that The mass percentage contents of the components in the mixed powder are: 47-78% of light-burned magnesia micro powder, 15-45% of pseudo-boehmite micro powder, and 6-16% of talc powder.
4. The MgO-Al2O3-ZrO2 refractory material according to claim 2, characterized in that The water addition amount is 90-150% of the mass of the mixed powder, the ball milling speed is 500-1000 r / min, and the ball milling time is 60-180 min.
5. The MgO-Al2O3-ZrO2 refractory material according to claim 2, characterized in that, The spraying amount of the ball milling slurry is 10-20% of the mass of the zirconia particles; the calcination temperature is 200-500℃, and the holding time is 3-6h.
6. The MgO-Al2O3-ZrO2 refractory material of claim 2, wherein, The light-burned magnesia powder has a MgO content≥99.5wt%, and a particle size≤10μm; the pseudo-boehmite powder has an impurity content less than 1000ppm, and a particle size≤10μm; the talc powder has a whiteness≥90%, and a particle size≤10μm; the zirconia particles have a ZrO2 content≥99.8wt%, and a particle size of 0.5-3mm.
7. The MgO-Al2O3-ZrO2 refractory material of claim 1, wherein, The binding agent is an alumina-zirconia sol with a solid content of 20-30%, a mass ratio of alumina to zirconia of 1:(0.5-2), and a pH value of 1-3.
8. The MgO-Al2O3-ZrO2 refractory material of claim 1, wherein, The fused white corundum particles have an Al2O3 content≥99.4wt%, and a particle size≤1mm; the fused magnesia particles have an MgO content≥97.8wt%, and a particle size≤1mm; the magnesia micro powder has an MgO content≥97.8wt%, and a particle size≤70μm; the alumina micro powder has an Al2O3 content≥99.6wt%, and a particle size≤70μm.
9. A method for producing a MgO-Al2O3-ZrO2 refractory material according to any one of claims 1 to 8, characterized in that, including the following steps: 1) uniformly stirring the raw materials except the binding agent, and then uniformly mixing the binding agent to obtain a mixed paste; 2) drying the mixed paste after being pressed into a green body, and then sintering to obtain a MgO-Al2O3-ZrO2 refractory material.
10. The method of producing a MgO-Al2O3-ZrO2 refractory material according to claim 9, characterized in that, The pressing pressure is 80-120MPa; the drying temperature is 80-110℃, and the drying time is 24-36h; the sintering temperature is 1600-1750℃, and the holding time is 3-6h.