High-performance alkali-resistant and wear-resistant castable containing basalt cast stone and preparation method thereof

Abstract

The invention relates to the technical field of refractory materials, in particular to a high-performance alkali-resistant and wear-resistant castable containing basalt cast stone and a preparation method thereof.The high-performance alkali-resistant and wear-resistant castable is prepared from, by mass, 65-80% of basalt cast stone with the particle size being 0-8 mm, 6-8% of high-alumina cement, 10-18% of mullite micro powder, 10-12% of silicon micro powder and 0.2-0.35% of efficient water reducing agent. The preparation method comprises the following steps: sequentially putting the raw materials into a stirrer for mixing, then adding 6.0-6.5% of water for stirring, obtaining mixed slurry after stirring, carrying out casting molding, then naturally curing, demolding, then putting into a curing box for curing, putting the cured finished product into a drying oven for drying, putting the dried finished product into a high-temperature electric furnace for firing, and naturally cooling after firing. The main crystal phase ordinary pyroxene in the basalt cast stone is high in chemical inertness and compact and stable in structure, so that the prepared high-strength alkali-resistant castable containing the basalt cast stone has the characteristics of excellent alkali resistance and abrasive resistance.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, and in particular to a high-performance alkali-resistant and wear-resistant castable containing basalt cast stone and its preparation method. Background Technology

[0002] In the new dry-process cement rotary kiln system, key components such as the preheater, decomposer, and kiln tail flue are constantly operating at 300-1100 °C, and are rich in alkali metal vapors such as K2O and Na2O volatilized from raw materials and fuels. These alkaline components react chemically with components such as SiO2 and Al2O3 in traditional refractory castables to generate new phases such as potassium nepheline and leucite, accompanied by significant volume expansion. This ultimately leads to stress cracks and structural spalling inside the castable, severely shortening the lining life and affecting production stability. Therefore, high-performance alkali-resistant castables that can effectively resist alkali vapor erosion are required for this part. Existing traditional alkali-resistant castables contain silicon carbide. After oxidation, silicon carbide forms an oxide film on the surface of the product to block alkali vapor erosion. However, the formulation contains a large proportion of silicon carbide, and silicon carbide is expensive, resulting in a high overall product cost.

[0003] Basalt cast stone is a high-performance industrial material made from natural basalt as the main raw material, supplemented with coke, chromite and other corrective materials, and melted at 1290℃~1400℃, cast into shape and subjected to controlled crystallization heat treatment. Basalt cast stone is mainly used in wear-resistant components such as plate and pipe manufacturing, and has not been used in the field of refractory materials.

[0004] Traditional alkali-resistant castables are expensive due to the use of silicon carbide aggregates, increasing overall production costs. Basalt cast stone, on the other hand, offers advantages such as readily available raw materials, high wear resistance, and corrosion resistance. Therefore, there is an urgent need to develop a high-performance alkali-resistant and wear-resistant castable containing basalt cast stone, along with its preparation method, to meet the requirements of actual production environments and overcome current shortcomings in practical production. Summary of the Invention

[0005] This invention provides a high-performance alkali-resistant and wear-resistant castable containing basalt cast stone and its preparation method. The basalt cast stone is applied to the castable in a cement rotary kiln with an operating environment temperature below 1100℃ and a strong alkalinity. The basalt cast stone is rich in acidic oxides, which react with alkali metal oxides to generate a high-viscosity glass phase. This glass phase can effectively cover and passivate the aggregate surface and block further penetration and erosion of the alkaline medium, thereby improving the alkali resistance of the castable.

[0006] To achieve the above objectives, the present invention provides a high-performance alkali-resistant and wear-resistant castable containing basalt cast stone, characterized in that the raw materials are composed of the following mass percentages: 65-80% basalt cast stone with a particle size of 0-8mm, 6-8% high-alumina cement, 10-18% mullite powder, 10-12% silica powder, and 0.2-0.35% high-efficiency water-reducing agent.

[0007] Furthermore, basalt cast stone is made from natural basalt as raw material, which is melted at 1290℃~1400℃, cast into shape, and subjected to controlled crystallization heat treatment. It is then sorted, crushed, and sieved into particles with a diameter of 0~8mm. Its bulk density is 2.8~3.1 g / cm3, apparent porosity is 2.5~3.0%, water absorption rate is 0.5~1%, and its main chemical components are Al2O3, CaO, MgO, and SiO2.

[0008] Furthermore, the fineness of the high-alumina cement is <0.0074mm.

[0009] Furthermore, the mullite powder has a particle size of <5μm.

[0010] Furthermore, the SiO2 content in the silicon micropowder is >95wt%.

[0011] Furthermore, the high-efficiency water-reducing agent is one or more of sodium tripolyphosphate, sodium hexametaphosphate, and naphthalene-based water-reducing agents in combination.

[0012] The preparation method of this high-performance alkali-resistant and wear-resistant castable containing basalt cast stone includes the following specific steps: S1. Weigh the raw materials according to the mass percentage of their composition; S2. Add the weighed raw materials and high-efficiency water-reducing agent into the mixer and mix for 30 seconds. Then add 6.0-6.5% water and mix for 180 seconds. After mixing evenly, a mixed slurry is obtained. S3. Pour the mixed slurry into the triple mold and cast it by gravity. Then let it harden naturally. After the hardening time is 12 hours, demold it and place it in the curing box for 24 hours. S4. Place the cured finished product into an oven for drying at 110℃ for 24 hours; S5. Place the dried finished product into a high-temperature electric furnace for firing at 1100℃ for 3 hours. After firing, allow it to cool naturally to room temperature.

[0013] In this invention, the basalt cast stone contains SiO2 and Al2O3, especially a large amount of acidic oxides. These acidic oxides are very stable under high temperature conditions. At the same time, the acidic oxides react with alkali metal oxides to form a high-viscosity silicate or aluminosilicate glass phase. This silicate or aluminosilicate glass phase can effectively cover and passivate the surface of the aggregate, blocking further penetration and erosion of alkaline media. Therefore, the castable containing basalt cast stone aggregate has better alkali resistance and can work normally in alkaline working environments.

[0014] In addition, basalt cast stone is an organic combination of high hardness (Mohs hardness ≥7) pyroxene microcrystalline structure and high toughness. When it is distributed as aggregate in castables, it can effectively resist external friction and wear. These basalt cast stone aggregates may form a support structure similar to a "skeleton" in the castables, enhancing the overall wear resistance of the material.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes the fact that acidic oxides in basalt cast stone do not react in high-temperature environments, while simultaneously reacting with alkali metal oxides to form a high-viscosity glassy phase. This glassy phase effectively covers and passivates the aggregate surface, ensuring the stability of the overall castable. Furthermore, the basalt cast stone-containing castable of this invention is primarily used in working environments below 1100℃ and in highly alkaline conditions, such as cement rotary kilns. Therefore, the prepared high-performance alkali-resistant and wear-resistant castable containing basalt cast stone possesses excellent alkali resistance and wear resistance, along with low cost. 2. After multiple experiments, the wear resistance of high-strength alkali-resistant castable containing basalt cast stone is 20% higher than that of traditional castables using 65 alumina aggregate. The raw material of basalt cast stone is mostly natural basalt, which is abundant and much cheaper than fused alumina and silicon carbide. Moreover, the existing preparation process is mature and conforms to the current concept of environmental protection and sustainable development. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the crucible cross-sectional permeation area for alkali resistance tests in Examples 1, 2, 3, and the comparative example. Detailed Implementation

[0017] The embodiments of the present invention are described in detail, but this should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

[0018] It should be noted that the basalt cast stone used in this invention contains a large amount of acidic oxides, which are very stable under high temperature conditions. At the same time, the acidic oxides react with alkali metal oxides to generate a high-viscosity silicate or aluminosilicate glass phase. This silicate or aluminosilicate glass phase can effectively cover and passivate the surface of the aggregate, blocking further penetration and erosion of alkaline media. Finally, after recrystallization, the main crystalline phase of the basalt cast stone is ordinary pyroxene. This crystal structure is dense, stable, and chemically inert, and its lattice is difficult to be destroyed by alkaline solution.

[0019] Secondly, basalt cast stone has an organic combination of high hardness (Mohs hardness ≥7) pyroxene microcrystalline structure and high toughness. After hardness testing, the wear resistance of basalt cast stone is more than 10 times that of manganese steel. This means that in the later wear process, basalt cast stone can not only resist cutting wear, but its interwoven crystal structure can also effectively inhibit crack propagation and avoid brittle spalling, showing better impact wear resistance. Therefore, basalt cast stone was selected as the main raw material for the batching experiment.

[0020] The following detailed description of the high-performance alkali-resistant and wear-resistant castable containing basalt cast stone and its preparation method is provided through specific embodiments.

[0021] The basalt cast stone used in this invention is made from natural basalt as the main raw material, supplemented with corrective materials such as coke and chromite, and is produced by melting at 1290℃~1400℃, casting, and controlled crystallization heat treatment. Its bulk density is 2.8~3.1 g / cm³. 3 It has a porosity of 2.5-3.0% and a water absorption rate of 0.5-1%. Among them, basalt cast stone is rich in SiO2 and Al2O3. Example

[0022] The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone in Example 1 comprises the following raw materials by weight percentage: 72% 0-8mm basalt cast stone, 6.5% high-alumina cement, 12% mullite powder, 10% silica powder, and 0.31% sodium tripolyphosphate, a high-efficiency water-reducing agent.

[0023] The above Example 1 is prepared by the following steps to prepare a high-performance alkali-resistant and wear-resistant castable containing basalt cast stone: S1. Weigh the raw materials according to the mass percentage of their composition; S2. Add the weighed raw materials and high-efficiency water-reducing agent into the mixer and mix for 30 seconds. Then add 6.5% water and mix for 180 seconds. After mixing evenly, a mixed slurry is obtained. S3. Pour the mixed slurry into the triple mold and cast it by gravity. Then let it harden naturally. After the hardening time is 12 hours, demold it and place it in the curing box for 24 hours. S4. Place the cured finished product into an oven for drying at 110℃ for 24 hours; S5. Place the dried finished product into a high-temperature electric furnace for firing at 1100℃ for 3 hours. After firing, allow it to cool naturally to room temperature.

[0024] The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone prepared in Example 1 was subjected to physical property testing, wear resistance testing, and alkali resistance testing. The tested physical properties and wear resistance are shown in Table 1.

[0025] Table 1. Test Performance Results

[0026] The alkali resistance of Example 1 is as follows: Figure 1 As shown in (b1). Example

[0027] The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone in Example 2 comprises the following raw materials by weight percentage: 70% 0-8mm basalt cast stone, 6% high-alumina cement, 14% mullite powder, 10.5% silica powder, and 0.31% sodium tripolyphosphate, a high-efficiency water-reducing agent.

[0028] Example 2 above describes the preparation of a high-performance alkali-resistant and wear-resistant castable containing basalt cast stone through the following steps: S1. Weigh the raw materials according to the mass percentage of their composition; S2. Add the weighed raw materials and high-efficiency water-reducing agent into the mixer and mix for 30 seconds. Then add 6.2% water and mix for 180 seconds. After mixing evenly, a mixed slurry is obtained. S3. Pour the mixed slurry into the triple mold and cast it by gravity. Then let it harden naturally. After the hardening time is 12 hours, demold it and place it in the curing box for 24 hours. S4. Place the cured finished product into an oven for drying at 110℃ for 24 hours; S5. Place the dried finished product into a high-temperature electric furnace for firing at 1100℃ for 3 hours. After firing, allow it to cool naturally to room temperature.

[0029] The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone prepared in Example 2 was subjected to physical property testing, wear resistance testing, and alkali resistance testing. The tested physical properties and wear resistance are shown in Table 2.

[0030] Table 2 Detection Performance Results

[0031] The alkali resistance of Example 2 is as follows: Figure 1 As shown in (b2). Example

[0032] The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone in Example 3 comprises the following raw materials by weight percentage: 68% 0-8mm basalt cast stone, 6.8% high-alumina cement, 16% mullite powder, 10.2% silica powder, and 0.29% sodium tripolyphosphate, a high-efficiency water-reducing agent.

[0033] Example 3 above describes the preparation of a high-performance alkali-resistant and wear-resistant castable containing basalt cast stone through the following steps: S1. Weigh the raw materials according to the mass percentage of their composition; S2. Add the weighed raw materials and high-efficiency water-reducing agent into the mixer and mix for 30 seconds. Then add 6.5% water and mix for 180 seconds. After mixing evenly, a mixed slurry is obtained. S3. Pour the mixed slurry into the triple mold and cast it by gravity. Then let it harden naturally. After the hardening time is 12 hours, demold it and place it in the curing box for 24 hours. S4. Place the cured finished product into an oven for drying at 110℃ for 24 hours; S5. Place the dried finished product into a high-temperature electric furnace for firing at 1100℃ for 3 hours. After firing, allow it to cool naturally to room temperature.

[0034] The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone prepared in Example 3 was subjected to physical property testing, wear resistance testing, and alkali resistance testing. The tested physical properties and wear resistance are shown in Table 3.

[0035] Table 3. Test Performance Results

[0036] The alkali resistance of Example 3 is as follows: Figure 1 As shown in (b3).

[0037] Comparative Example The composition consists of 36% alumina aggregate with a particle size of 0-8mm, 36% solid waste high-voltage electric porcelain aggregate with a particle size of 0-8mm, 12% mullite powder, 10% silica powder, 6% high-alumina cement, and 0.31% sodium tripolyphosphate, a high-efficiency water-reducing agent.

[0038] The above Comparative Example 1 was prepared using the following steps to create a castable refractory that does not contain basalt: S1. Weigh the raw materials according to the mass percentage of their composition; S2. Add the weighed raw materials and high-efficiency water-reducing agent into the mixer and mix for 30 seconds. Then add 6.5% water and mix for 180 seconds. After mixing evenly, a mixed slurry is obtained. S3. Pour the mixed slurry into the triple mold and cast it by gravity. Then let it harden naturally. After the hardening time is 12 hours, demold it and place it in the curing box for 24 hours. S4. Place the cured finished product into an oven for drying at 110℃ for 24 hours; S5. Place the dried finished product into a high-temperature electric furnace for firing at 1100℃ for 3 hours. After firing, allow it to cool naturally to room temperature.

[0039] Physical properties, wear resistance, and alkali resistance of the basalt-free castable prepared in proportion were tested. The tested physical properties and wear resistance are shown in Table 4.

[0040] Table 4. Test Performance Results

[0041] And the alkali resistance of the comparison ratio is as follows Figure 1 As shown in (a).

[0042] A comparison of the performance test results of the refractory castables prepared in Examples 1-3 and the comparative example shows that in Examples 1-3, as the amount of basalt cast stone added increases, the bending strength and wear resistance are improved to varying degrees. Compared with the traditional raw material 65 alumina aggregate used in the comparative example, both the bending strength and wear resistance are increased.

[0043] Secondly, such as Figure 1 As shown in the test results of the alkali resistance of the refractory castables prepared in Examples 1-3 and the comparative example, it can be seen from the crucible cross-section that the penetration area of ​​the crucible cross-section in Examples 1-3 is smaller than that in the comparative example. Therefore, the alkali resistance of the high-performance alkali-resistant and wear-resistant castable containing basalt cast stone used in this invention is higher than that of the castable using traditional 65 alumina aggregate, thereby reducing costs while improving the alkali resistance of the castable.

[0044] Preferably, the physical property testing in this invention includes bulk density, apparent porosity, and room temperature compressive strength. Bulk density and apparent porosity are tested using Archimedes' displacement method, according to the national standard GB / T2997-2015 "Test Methods for Bulk Density, Apparent Porosity and True Porosity of Dense Shaped Refractory Products". Room temperature compressive strength is tested using a pressure testing machine, according to GB / T5072-2008 "Test Method for Room Temperature Compressive Strength of Refractory Materials", with a loading rate of 0.5 MPa / s, until... The sample was destroyed, the maximum pressure value was recorded, and the compressive strength was calculated. Next, the abrasion resistance was tested according to the national standard GB / T18301-2012 "Test Method for Abrasion Resistance of Refractory Materials at Room Temperature". 1000g of silicon carbide sand of a specified particle size was vertically sprayed onto the flat surface of the sample through a sandblasting pipe using 450kPa compressed air, and the wear volume of the sample was measured. Finally, the alkali resistance was tested according to the molten alkali crucible method in GB / T14983-2008 "Test Method for Alkali Resistance of Refractory Materials", and cross-sectional analysis was used for measurement and analysis. In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" and their orientation or positional relationships are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0045] The present invention has been described by the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A high-performance alkali-resistant and wear-resistant castable containing basalt cast stone, characterized in that, The raw materials are composed of the following percentages by weight: 65-80% basalt cast stone with a particle size of 0-8mm, 6-8% high-alumina cement, 10-18% mullite powder, 10-12% silica powder, and 0.2-0.35% high-efficiency water-reducing agent.

2. The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone according to claim 1, characterized in that, Basalt cast stone is made from natural basalt as raw material, which is melted at 1290℃~1400℃, cast into shape, and subjected to controlled crystallization heat treatment. It is then sorted, crushed, and sieved into particles with a diameter of 0~8mm, and its bulk density is 2.8~3.1 g / cm³. 3 The apparent porosity is 2.5-3.0%, the water absorption rate is 0.5-1%, and the main chemical components are Al2O3, CaO, MgO, and SiO2.

3. The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone according to claim 1, characterized in that, The fineness of high-alumina cement is <0.0074mm.

4. The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone according to claim 1, characterized in that, Mullite micron powder, particle size <5μm.

5. The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone according to claim 1, characterized in that, The SiO2 content in the silicon micropowder is >95wt%.

6. The high-performance alkali-resistant and wear-resistant castable containing basalt cast stone according to claim 1, characterized in that, The high-efficiency water-reducing agent is one or more of sodium tripolyphosphate, sodium hexametaphosphate, and naphthalene-based water-reducing agents.

7. The preparation method of a high-performance alkali-resistant and wear-resistant castable containing basalt cast stone as described in claim 1, characterized in that, The specific steps include the following: S1. Weigh the raw materials according to the mass percentage of their composition; S2. Add the weighed raw materials and high-efficiency water-reducing agent into the mixer and mix for 30 seconds. Then add 6.0-6.5% water and mix for 180 seconds. After mixing evenly, a mixed slurry is obtained. S3. Pour the mixed slurry into the triple mold and cast it by gravity. Then let it harden naturally. After the hardening time is 12 hours, demold it and place it in the curing box for 24 hours. S4. Place the cured finished product into an oven for drying at 110℃ for 24 hours; S5. Place the dried finished product into a high-temperature electric furnace for firing at 1100℃ for 3 hours. After firing, allow it to cool naturally to room temperature.

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