Al2O3-SiC-MgAl2O4-C castable prepared from waste magnesia-carbon material and preparation method of Al2O3-SiC-MgAl2O4-C castable

Abstract

The invention discloses an Al2O3-SiC-MgAl2O4-C castable prepared from waste magnesia carbon materials and a preparation method of the Al2O3-SiC-MgAl2O4-C castable, and belongs to the technical field of unshaped refractory materials, the Al2O3-SiC-MgAl2O4-C castable is prepared from white corundum aggregate, silicon carbide, waste magnesia carbon bricks, spherical asphalt, alpha-Al2O3 fine powder, silicon oxide fine powder, monatomic silicon powder and calcium aluminate cement as raw materials, and a water reducing agent and water are added; the preparation method comprises the following steps: mixing the materials in a stirrer, stirring, pouring and molding, curing at room temperature, demolding, drying for 36-50 hours, carrying out heat treatment at 1550-1650 DEG C in a carbon-buried atmosphere, and keeping the temperature for 3-5 hours to obtain the refractory castable for the iron runner by using the waste magnesia carbon bricks. The prepared refractory castable is excellent in high-temperature performance and high in oxidation resistance, the service life is obviously prolonged, and meanwhile resource recycling is enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of amorphous refractory materials, and particularly relates to a method for preparing Al2O3 from waste magnesium-carbon materials. 2 O 3 -SiC-MgAl 2 O 4 -C castable and preparation method thereof. Background Art

[0002] Chinese patent application number: 202010227598.3, the name of the invention is: A kind of Al containing recycled materials 2 O 3 -SiC-C brick and its preparation method. The application uses 20-30 parts of recycled material particles, 30-40 parts of high-alumina bauxite particles, 10-20 parts of corundum particles, 10-20 parts of corundum fine powder, 5-15 parts of silicon carbide fine powder, 5-15 parts of flake graphite, 0-5 parts of additives, and 2-6 parts of binder to prepare AlC-C brick with good resistance to slag erosion and molten iron scouring, high high-temperature flexural strength, excellent thermal shock stability, and stable high-temperature thermal expansion rate and residual expansion rate. 2 O 3 -SiC-C bricks.

[0003] Chinese patent application number: 202210319678.0, the name of the invention is: A composite lining brick for a torpedo tank produced by recycling a variety of waste refractory materials. The application is composed of special-grade alumina clinker, recycled waste silicon carbide, white corundum, waste skateboard, expansion agent, recycled graphite, alumina micropowder, high-temperature asphalt powder, antioxidant, complex magnesium-aluminum binder, and phenolic resin. The raw materials of the protective layer lining brick are composed of recycled waste torpedo tank particles, waste skateboard, recycled waste silicon carbide, recycled waste iron ditch material, recycled waste corundum fine powder, expansion agent, recycled graphite, complex magnesium-aluminum binder, and phenolic resin to prepare a composite lining brick for a torpedo tank. The composite lining brick for a torpedo tank has the same performance indicators as the existing torpedo tank bricks while significantly reducing the production cost, and the use effect is also better than the existing torpedo tank bricks. The comprehensive cost is greatly reduced, and the unit consumption of refractory materials is greatly reduced, which has good social and economic benefits.

[0004] From the above research results, it can be seen that the use of waste refractory materials to prepare Al 2 O 3 -SiC-MgAl 2 O 4 -C refractory castables help improve Al 2 O 3 - Improve the service performance of SiC-C refractory castables, reduce production costs, protect the environment and promote circular economy.

[0005] As an important pillar of the national economy, the steel industry consumes a huge amount of resources every year and currently has overcapacity. The waste refractory materials produced in its production process not only occupy a large amount of land resources, but also have a serious impact on the ecological environment. At the same time, under the background of global resource shortage, the country's attention to the environment continues to increase, and the traditional production model that relies on primary ore can no longer meet the needs of sustainable development. In addition, as the pillar of the steel industry, the amount of waste refractory materials produced each year is huge. Therefore, it is urgent to explore a way to reuse waste refractory materials in the steel industry. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing Al from waste magnesium-carbon materials in order to solve the above problems. 2 O 3 -SiC-MgAl 2 O 4 -C castable and preparation method thereof.

[0007] The present invention achieves the above-mentioned purpose through the following technical solutions: Preparation of Al from waste magnesium-carbon materials 2 O 3 -SiC-MgAl 2 O 4 -C castable, with 50.0wt%-60.0wt% white corundum aggregate, 5.0wt%-15.0wt% silicon carbide, 10.0wt%-20.0wt% waste magnesia carbon bricks, 1.0wt%-2.0wt% spherical asphalt, 5.0wt%-10.0wt% α-Al 2 O 3 The raw materials are fine powder, 5.0wt%-10.0wt% of silicon oxide fine powder, 1.0wt%-3.0wt% of elemental silicon powder, and 1.0wt%-3.0wt% of calcium aluminate cement, and 0.1wt%-0.4wt% of water reducing agent and 4.0wt%-8.0wt% of water of the raw materials are added.

[0008] The white corundum aggregate is made of 10.0wt%-40.0wt% 8mm-5mm white corundum aggregate, 20.0wt%-30.0wt% 5mm-3mm white corundum aggregate, 20.0wt%-30.0wt% 3mm-1mm white corundum aggregate, and 20.0wt%-50.0wt% 1mm-0.088mm white corundum aggregate.

[0009] The silicon carbide is made of 10.0wt%-20.0wt% of 3mm-1mm silicon carbide, 10.0wt%-20.0wt% of 1mm-0.088mm silicon carbide, and 40.0wt%-70.0wt% of silicon carbide less than 0.088mm.

[0010] Among them, the MgO content of the waste magnesia carbon bricks is ≥75.0%, the C content is ≥10.0%, and the bulk density is ≥2.9g / cm 3 .

[0011] Among them, SiO 2 Content ≥97.0%.

[0012] Wherein, the water reducing agent is sodium tripolyphosphate or sodium hexametaphosphate.

[0013] Among them, the Si content in the elemental silicon powder is ≥95.0%.

[0014] Among them, the alumina content in calcium aluminate cement is ≥65.0%.

[0015] The present invention also provides a method for preparing Al from waste magnesium-carbon materials. 2 O 3 -SiC-MgAl 2 O 4 -C castable preparation method, using white corundum aggregate, silicon carbide, waste magnesia carbon bricks, spherical asphalt, α-Al 2 O 3 The iron ditch is prepared by mixing the above materials in a mixer, mixing and casting, and then removing the mold after curing at room temperature. After drying for 36 hours to 50 hours, heat treatment is carried out in a carbon-buried atmosphere at a temperature of 1550°C to 1650°C and heat preservation for 3 hours to 5 hours. 2 O 3 -SiC-MgAl 2 O 4 -C Refractory castable.

[0016] Among them, after heat treatment, Al 2 O 3 -SiC-MgAl 2 O 4 -C refractory castable bulk density is 2.8g / cm 3 -3.0g / cm 3 The flexural strength is 32-37MPa, the flexural strength retention rate after three wind-cooled thermal shock tests is 73%-82%, the oxidation index of the 1400℃ antioxidant test is 5%-10%, and the high-temperature flexural strength at 1400℃ is 9MPa-14MPa.

[0017] The advantages of the present invention are as follows: By introducing waste magnesia carbon bricks, the original Al 2 O 3 -The carbon black in SiC-C refractory castable can replace the carbon source and reduce the consumption of carbon resources; the waste magnesia carbon bricks are introduced into the refractory castable in the form of aggregates, and the carbon is stored in the particles, which can significantly reduce the contact area between carbon and air during service, thereby reducing the oxidation rate and increasing Al 2 O 3 -SiC-MgAl 2 O 4 -C refractory castables have an antioxidant capacity; waste magnesia carbon bricks are introduced as aggregates and can react with α-Al in the matrix 2 O 3 The reaction generates spinel phase. The formation of spinel can strengthen the interface between aggregate and matrix, fill the gap between some aggregate and matrix, and improve the high temperature performance. On the other hand, the formation of spinel can improve the Al 2 O 3 -SiC-MgAl 2 O 4 -C phase composition inside refractory castables, improve thermal shock resistance and high temperature strength. The in-situ reaction of spinel will cause volume expansion, but Al 2 O 3 -SiC-MgAl 2 O 4 -C refractory castables added with silicon oxide powder and elemental silicon powder will react with other phases at high temperature to form a low melting phase, on the one hand, through the liquid phase sintering to improve the Al 2 O 3 -SiC-MgAl 2 O 4 -C refractory castable sintering ability, alleviate the expansion caused by the formation of spinel, and the generated liquid phase can fill the gaps, reduce porosity, and improve high temperature performance. 2 O 3 -SiC-MgAl 2 O 4 -C refractory castables have excellent high temperature performance and strong anti-oxidation performance, which significantly improves the service life and enhances resource recycling. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to these embodiments.

[0019] Example 1 The present invention relates to a method for preparing Al from waste magnesium-carbon materials. 2 O3 -SiC-MgAl 2 O 4 -C castable and preparation method thereof, the technical scheme thereof is: The raw material of the composite material is 50wt% white corundum aggregate, 10wt% silicon carbide, 20wt% waste magnesia carbon brick, 2.0wt% spherical asphalt, 7wt% α-Al 2 O 3 The raw materials are 7wt% silica powder, 1.0wt% elemental silicon powder, and 3wt% calcium aluminate cement; 0.2wt% water reducer and 6.0wt% water of the raw materials are added. The above materials are mixed in a mixer for 7 minutes, stirred for 4 minutes, and then cast into shape. After curing at room temperature for 40 hours, they are demoulded, dried for 36 hours, and then heat treated in a carbon atmosphere at a temperature of 1550°C. After keeping warm for 3 hours, the iron ditch is prepared by using waste magnesium carbon bricks to prepare Al 2 O 3 -SiC-MgAl 2 O 4 -C Refractory castable.

[0020] Among them, 8mm-5mm white corundum aggregate accounts for 30wt%, 5mm-3mm white corundum aggregate accounts for 30.0wt%, 3mm-1mm white corundum aggregate accounts for 20.0wt%, and 1mm-0.088mm white corundum aggregate accounts for 20.0wt%.

[0021] Among them, 3mm-1mm silicon carbide accounts for 20.0wt%, 1mm-0.088mm silicon carbide accounts for 20.0wt%, and silicon carbide less than 0.088mm accounts for 60.0wt% of silicon carbide.

[0022] Among them, the MgO content of the waste magnesia carbon brick is 78.0%, the C content is 12.0%, and the volume density is 2.97g / cm 3 , 1mm-3mm waste magnesia carbon bricks accounted for 50.0%, and 0mm-1mm waste magnesia carbon bricks accounted for 50.0%.

[0023] Among them, SiO 2 The content is 97.0%.

[0024] Among them, the water reducing agent is sodium tripolyphosphate.

[0025] Among them, the Si content in the elemental silicon powder is 96.0%.

[0026] Among them, the alumina content in calcium aluminate cement is 67.0%.

[0027] After testing, Al 2 O 3 -SiC-MgAl2 O 4 -C refractory castable bulk density is 2.93g / cm 3 The flexural strength is 34MPa, the flexural strength retention rate after three wind-cooled thermal shock tests is 77%, the oxidation index of the 1400℃ antioxidant test is 6%, and the high-temperature flexural strength at 1400℃ is 12MPa.

[0028] Example 2 The present invention relates to a method for preparing Al from waste magnesium-carbon materials. 2 O 3 -SiC-MgAl 2 O 4 -C castable and preparation method thereof, the technical scheme thereof is: The raw material of the composite material is 55.0wt% white corundum aggregate, 15.0wt% silicon carbide, 10.0wt% waste magnesia carbon brick, 2.0wt% spherical asphalt, 7.0wt% α-Al 2 O 3 The raw materials are 0.3wt% water reducer and 5.0wt% water of the raw materials. The above materials are mixed in a mixer for 8 minutes, stirred for 4 minutes and cast into shape. After curing at room temperature for 48 hours, they are demoulded, dried for 36 hours and then heat treated in a carbon atmosphere at a temperature of 1650℃. After heat preservation for 5 hours, the iron ditch is prepared by using waste magnesium carbon bricks to prepare Al 2 O 3 -SiC-MgAl 2 O 4 -C Refractory castable.

[0029] Among them, 8mm-5mm white corundum aggregate accounts for 30.0wt%, 5mm-3mm white corundum aggregate accounts for 20.0wt%, 3mm-1mm white corundum aggregate accounts for 20.0wt%, and 1mm-0.088mm white corundum aggregate accounts for 30.0wt%.

[0030] Among them, 3mm-1mm silicon carbide accounts for 20.0wt%, 1mm-0.088mm silicon carbide accounts for 10.0wt%, and silicon carbide less than 0.088mm accounts for 70.0wt%.

[0031] Among them, the MgO content of the waste magnesia carbon brick is 85%, the C content is 10%, and the volume density is 2.92g / cm 3 , 1mm-3mm waste magnesia carbon bricks accounted for 60.0%, and 0mm-1mm waste magnesia carbon bricks accounted for 40.0%.

[0032] Among them, SiO 2 The content is 98%.

[0033] Among them, the water reducing agent is sodium hexametaphosphate.

[0034] Among them, the Si content in elemental silicon powder is 97.0%.

[0035] Among them, the alumina content in calcium aluminate cement is 68.0%.

[0036] After testing, Al 2 O 3 -SiC-MgAl 2 O 4 -C refractory castable bulk density is 2.94g / cm 3 The flexural strength is 36MPa, the flexural strength retention rate after three wind-cooled thermal shock tests is 80%, the oxidation index of the 1400℃ antioxidant test is 7%, and the high-temperature flexural strength at 1400℃ is 14MPa.

[0037] Example 3 The present invention relates to a method for preparing Al from waste magnesium-carbon materials. 2 O 3 -SiC-MgAl 2 O 4 -C castable and preparation method thereof, the technical scheme thereof is: The raw material of the composite material is 50.0wt% white corundum aggregate, 15.0wt% silicon carbide, 10.0wt% waste magnesia carbon brick, 2.0wt% spherical asphalt, 10.0wt% α-Al 2 O 3 The raw materials are 10.0wt% silica powder, 2.0wt% elemental silicon powder, and 1.0wt% calcium aluminate cement; 0.1wt% water reducer and 8.0wt% water are added. The above materials are mixed in a mixer for 6 minutes, stirred for 5 minutes, and cast into shape. After curing at room temperature for 50 hours, the mold is removed. After drying for 50 hours, heat treatment is carried out in a carbon-buried atmosphere at a temperature of 1600°C. After keeping warm for 4 hours, the iron ditch is prepared by using waste magnesium carbon bricks to prepare Al 2 O 3 -SiC-MgAl 2 O 4 -C Refractory castable.

[0038] Among them, 8mm-5mm white corundum aggregate accounts for 40.0wt%, 5mm-3mm white corundum aggregate accounts for 20.0wt%, 3mm-1mm white corundum aggregate accounts for 20.0wt%, and 1mm-0.088mm white corundum aggregate accounts for 20.0wt%.

[0039] Among them, 3mm-1mm silicon carbide accounts for 20.0wt%, 1mm-0.088mm silicon carbide accounts for 10.0wt%, and silicon carbide less than 0.088mm accounts for 70.0wt%.

[0040] Among them, the MgO content of the waste magnesia carbon brick is 76.0%, the C content is 13.0%, and the volume density is 2.91g / cm 3 , 1mm-3mm waste magnesia carbon bricks account for 70.0% of the waste magnesia carbon bricks, and 0mm-1mm waste magnesia carbon bricks account for 30.0% of the waste magnesia carbon bricks.

[0041] Among them, SiO 2 The content is 97.0%.

[0042] Among them, the water reducing agent is sodium tripolyphosphate.

[0043] Among them, the Si content in elemental silicon powder is 97.0%.

[0044] Among them, the alumina content in calcium aluminate cement is 69.0%.

[0045] After testing, Al 2 O 3 -SiC-MgAl 2 O 4 -C refractory castable bulk density is 2.98g / cm 3 The flexural strength is 35MPa, the flexural strength retention rate after three wind-cooled thermal shock tests is 81%, the oxidation index of the 1400℃ antioxidant test is 5%, and the high-temperature flexural strength at 1400℃ is 12MPa.

[0046] Due to the adoption of the above technical solution, the present invention has the following positive effects compared with the prior art: The present invention uses waste magnesia carbon bricks as a new carbon source to introduce into Al 2 O 3 -SiC-MgAl 2 O 4 -C refractory castables can help generate a third phase to improve the microstructure interface and enhance service performance, and can also help reduce the consumption of carbon resources and benefit environmental protection.

[0047] The Al prepared by the present invention 2 O 3 -SiC-MgAl 2 O 4 -C refractory castable has excellent high temperature performance, strong oxidation resistance and significant effect on improving service life.

[0048] The above-mentioned embodiments only express the implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for preparing Al2O3-SiC-MgAl2O4-C castable from waste magnesium-carbon materials, characterized in that: The raw materials include 50.0wt%-60.0wt% of white corundum aggregate, 5.0wt%-15.0wt% of silicon carbide, 10.0wt%-20.0wt% of waste magnesia carbon bricks, 1.0wt%-2.0wt% of spherical asphalt, 5.0wt%-10.0wt% of α-Al2O3 fine powder, 5.0wt%-10.0wt% of silica fine powder, 1.0wt%-3.0wt% of elemental silicon powder, and 1.0wt%-3.0wt% of calcium aluminate cement, and 0.1wt%-0.4wt% of a water reducer and 4.0wt%-8.0wt% of water of the raw materials are added.

2. The Al2O3-SiC-MgAl2O4-C castable prepared from waste magnesium-carbon materials according to claim 1, characterized in that: The white corundum aggregate is made of 10.0wt%-40.0wt% of 8mm-5mm white corundum aggregate, 20.0wt%-30.0wt% of 5mm-3mm white corundum aggregate, 20.0wt%-30.0wt% of 3mm-1mm white corundum aggregate, and 20.0wt%-50.0wt% of 1mm-0.088mm white corundum aggregate.

3. The Al2O3-SiC-MgAl2O4-C castable prepared from waste magnesium-carbon materials according to claim 1, characterized in that: The silicon carbide is made of 10.0wt%-20.0wt% of 3mm-1mm silicon carbide, 10.0wt%-20.0wt% of 1mm-0.088mm silicon carbide, and 40.0wt%-70.0wt% of silicon carbide less than 0.088mm.

4. The Al2O3-SiC-MgAl2O4-C castable prepared from waste magnesium-carbon materials according to claim 1, characterized in that: The waste magnesia carbon bricks have a MgO content of ≥75.0%, a C content of ≥10.0%, and a bulk density of ≥2.9 g / cm 3 .

5. The Al2O3-SiC-MgAl2O4-C castable prepared from waste magnesium-carbon materials according to claim 1, characterized in that: The SiO2 content in the silicon oxide fine powder is ≥97.0%.

6. The Al2O3-SiC-MgAl2O4-C castable prepared from waste magnesium-carbon materials according to claim 1, characterized in that: The water reducing agent is sodium tripolyphosphate or sodium hexametaphosphate.

7. The Al2O3-SiC-MgAl2O4-C castable prepared from waste magnesium-carbon materials according to claim 1, characterized in that: The Si content in the elemental silicon powder is ≥95.0%.

8. The Al2O3-SiC-MgAl2O4-C castable prepared from waste magnesium-carbon materials according to claim 1, characterized in that: The alumina content in the calcium aluminate cement is ≥65.0%.

9. A method for preparing Al2O3-SiC-MgAl2O4-C castable from waste magnesium-carbon materials according to any one of claims 1-8, characterized in that: White corundum aggregate, silicon carbide, waste magnesia carbon bricks, spherical asphalt, α-Al2O3 fine powder, silicon oxide fine powder, elemental silicon powder, calcium aluminate cement are used as raw materials, and a water reducer and water are added; the above materials are mixed in a mixer, stirred and cast into shape, and demolded after room temperature curing. After drying for 36 to 50 hours, heat treatment is carried out in a carbon-buried atmosphere at a heat treatment temperature of 1550°C to 1650°C, and the heat treatment is kept for 3 to 5 hours to obtain Al2O3-SiC-MgAl2O4-C refractory castable for iron ditch using waste magnesia carbon bricks.

10. The method for preparing Al2O3-SiC-MgAl2O4-C castable from waste magnesium-carbon materials according to claim 9, characterized in that: The bulk density of Al2O3-SiC-MgAl2O4-C refractory castable after heat treatment is 2.8g / cm 3 -3.0g / cm 3 The flexural strength is 32-37MPa, the flexural strength retention rate after three wind-cooled thermal shock tests is 73%-82%, the oxidation index of the 1400℃ antioxidant test is 5%-10%, and the high-temperature flexural strength at 1400℃ is 9MPa-14MPa.