A method for preparing high-strength foamed ceramic

Abstract

The application provides a preparation method of high-strength foamed ceramic, comprising the following steps: S1, lithium mica tailings, combustion-supporting agent sodium tetraborate and fly ash are ball milled for a period of time and dried, and then the lithium mica tailings, the combustion-supporting agent and the fly ash are configured into first foaming powder according to a mass ratio of 50-60:3:25-40; S2, the first foaming powder is transferred into a ball mill, metal strips are added, and the ball mill is stirred for a period of time to obtain second foaming powder; S3, foaming agent powder is mixed with a solution for granulation to obtain foaming material, 2-5% of the foaming material by weight of the second foaming powder is uniformly sprayed and added to the surface of the second foaming powder, and then the second foaming material is granulated to obtain a material to be fired; and S4, the material to be fired is placed into a mold, compacted and fired at 1200-1300 DEG C to obtain high-strength foamed ceramic. The method can reduce the foaming unevenness, reduce the temperature required for foaming and reduce the processing cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a preparation method of high-strength foamed ceramics. BACKGROUND

[0002] At present, there are related researches on foamed ceramics prepared by using polished brick slag, fly ash, granite debris, cathode ray tube and various metal lithium mica tailings. However, the existing researches mostly take raw materials as the design object, and the research and development cycle is long, and due to the great difference in the composition of different raw materials, it is difficult to guide the research results to prepare foamed ceramics from large solid waste.

[0003] At present, the composition design of foamed ceramic wall materials lacks theoretical guidance, the pore structure and mechanical properties of foamed ceramics with the same density are significantly different, and the influencing factors and control mechanisms are not clear. In addition, due to the lack of systematic research on the relationship between the composition-foaming performance-pore structure-physical properties of foamed ceramics, the influencing factors of the pore structure and mechanical properties of foamed ceramics have not been revealed, and it is difficult to realize the pore structure control and high-strength preparation of foamed ceramics, so the performance indicators of the existing foamed ceramics cannot meet the demand, and the mechanical properties of foamed ceramics with the same density are significantly different. Therefore, the research on the material design method guided by chemical composition or phase composition, and the revealing of the influencing factors and their mutual relationship of the pore structure and mechanical properties, has become a research direction to be developed to promote the preparation of high-performance foamed ceramics from large solid waste.

[0004] Based on this, the present application systematically studies the relationship among composition-pore structure-performance of foamed ceramic slag, reveals the formation mechanism and influencing factors of the pore structure of foamed ceramic, and clearly defines the compression failure behavior and strengthening mechanism of foamed ceramic, and proposes the design principle and preparation method of high-strength foamed ceramic. SUMMARY

[0005] In order to overcome the problems of foamed ceramics in the prior art, the present application provides a novel high-strength foamed ceramic processing method, which can reduce the occurrence of uneven foaming, reduce the temperature required for foaming, reduce the hard conditions required for foaming, thereby reducing the processing cost.

[0006] Specifically, the present application provides the following technical scheme:

[0007] A preparation method of high-strength foamed ceramics, comprising:

[0008] Step S1, the lithium mica tailings, the combustion-supporting agent sodium tetraborate, and the fly ash are ball milled for a period of time and dried, and then a first foaming powder is prepared according to the mass ratio of lithium mica tailings: combustion-supporting agent: fly ash = 50-60: 3: 25-40;

[0009] Step S2, transferring the first foaming powder into a ball mill, adding metal strips accounting for 25-35% of the mass of the first foaming powder, and stirring in the ball mill for a period of time to obtain a second foaming powder;

[0010] Step S3, mixing the foaming agent powder with the solution for granulation to obtain a foaming material, and uniformly spraying and adding 2-5wt% of the foaming material accounting for the weight of the second foaming powder to the surface of the second foaming powder, and then granulating the second foaming material to obtain a to-be-fired material;

[0011] Step S4, placing the to-be-fired material into a mold, compacting and placing it into a furnace to fire at 1200-1300℃ to obtain a high-strength foamed ceramic.

[0012] Optionally, in step S1, the ball milling speed is 150-250r / min, and the ball milling time is 4-8h; the drying temperature is 100-120℃, and the drying time is 12-24h.

[0013] Optionally, in step S2, the melting point of the added metal strips must be above 1200℃ to ensure that the metal strips have certain strength while foaming at high temperature, and the diameter of the metal strips is not more than 1mm and the length is not more than 1cm. The metal strips are preferably copper wires with high melting point and stable chemical properties. The stirring time is not less than 4h.

[0014] Optionally, in step S3, the diameter of the foaming agent powder is not more than 5μm to ensure that the metal strips can participate in the foaming process well and play a role in improving thermal conductivity and reducing the fluidity of liquid phase crystals; the foaming agent powder is SiC.

[0015] Optionally, in step S3, the ratio of the foaming agent powder to the solution for granulation is 2-5:15.

[0016] By adding the metal strips, the temperature transfer during foaming can be enhanced while ensuring that the metal strips are not melted at high temperature, and the high strength at high temperature can reduce the fluidity of the liquid phase crystals generated at high temperature, reduce the aggregation of a large number of bubbles caused by uneven foaming of the bubbles; secondly, adding metal strips in the foamed ceramic can enhance the strength of the foamed ceramic.

[0017] By adding the flux, the borax pentahydrate can decompose to form Na2O and [BO3] triangles during the high-temperature foaming of the foamed ceramic, the generated sodium oxide can induce the decomposition of Si-O bonds, and [BO3] can insert into the [[SiO]4] tetrahedron to break the glass structure, thereby reducing the glass softening temperature and allowing sintering at low temperature.

[0018] The content of silicon and aluminum in the foamed ceramic can be changed by adding the element regulator, so as to increase the strength of the foamed ceramic after shaping.

[0019] The granules formed in the granulation process can contain the foaming agent with equal mass fraction by spraying the foaming agent, so that the bubbles generated during foaming can be uniformly distributed in the foamed ceramic, the phenomena of bubble aggregation and local absence of bubbles are reduced, and the performance of the foamed ceramic can be effectively enhanced.

[0020] The technical scheme provided by the application has at least the following beneficial effects:

[0021] In the novel high-strength foamed ceramic processing method, the added metal strip can enhance the heat conductivity during foaming and the strength of the foamed ceramic, the added flux can reduce the temperature required during foaming, so that the foaming can be carried out at low temperature and the energy loss during foaming is reduced, the added element regulator can change the ratio of silicon and aluminum elements and enhance the strength of the foamed ceramic, and finally the foaming agent is added by spraying, so that the uniformity of the pores generated during foaming can be ensured and the performance of the foamed ceramic is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 The flow chart of the preparation method of the application is shown in the figure.

[0024] Figure 2 The foamed ceramic of the application is shown in the figure. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the application more clear, the technical scheme of the application will be described in detail below with reference to the drawings and specific embodiments.

[0026] Embodiment 1

[0027] According to the application, the content of silicon and aluminum in the foamed ceramic can be changed by adding the element regulator, so as to increase the strength of the foamed ceramic after shaping. Figure 1The process shown, the lithium mica tailings, combustion improver sodium tetraborate pentahydrate, fly ash and other foaming materials are ball milled for 4h-8h, and dried at 110°C for 12-24h, then configured in the proportion of 60:3:37; the prepared foaming powder is transferred to the ball mill, and 30wt% copper wire is added, the diameter of the copper wire is not more than 1mm, and the length is 1cm, then stirred in the ball mill for not less than 4h; the foaming agent SiC is uniformly mixed with water in the ratio of 2:15 to form a foaming material, and then the foaming material is uniformly sprayed on the stirred foaming powder and granulated; the granulated sintering material is transferred to the mold and sintered at 1250°C, to obtain high-strength foamed ceramics with porosity of 79.1%-80%, bulk density ≤400kg / m 3 , compressive strength ≥4MPa, water absorption more than 4%. Figure 2 The schematic diagram of the obtained foamed ceramics is shown in Figure 2 , wherein the short diagonal line represents a metal strip, , which shows the irregular distribution of the metal strip in the foamed ceramics, the length of the metal strip is not more than 1cm, and the diameter is not more than 1mm.

[0028] Example 2

[0029] According to the process shown in Figure 1 , the lithium mica tailings, combustion improver sodium tetraborate pentahydrate, fly ash and other foaming materials are ball milled for 4h-8h, and dried at 110°C for 12-24h, then configured in the proportion of 60:3:37; the prepared foaming powder is transferred to the ball mill, and 30wt% copper wire is added, the diameter of the copper wire is not more than 1mm, and the length is 1cm, then stirred in the ball mill for not less than 4h; the foaming agent SiC is uniformly mixed with water in the ratio of 2:15 to form a foaming material, and then the foaming material is uniformly sprayed on the stirred foaming powder and granulated; the granulated sintering material is transferred to the mold and sintered at 1250°C, to obtain high-strength foamed ceramics with porosity of 79.1%-80%, bulk density ≤400kg / m 3 , compressive strength ≥4MPa, water absorption more than 4%.

[0030] Example 3

[0031] According to the process shown in Figure 1The shown flow, lithium mica tailings, combustion improver sodium tetraborate pentahydrate, fly ash and other foaming materials are respectively ball milled for 4h-8h, and dried at 110℃ for 12-24h, then configured in the proportion of 57:3:40; the configured foaming powder is transferred to the ball mill, and 30wt% copper wire is added, the diameter of the copper wire is not more than 1mm, and the length is 1cm, then stirred in the ball mill for not less than 4h; the foaming agent SiC is uniformly mixed with water in the proportion of 2:15 as a foaming material, then the foaming material is uniformly sprayed on the stirred foaming powder and granulated; the granulated sintering material is transferred to the mold, and sintered at 1250℃, to obtain high-strength foamed ceramics with porosity of 79.1%-80%, bulk density≤400kg / m 3 , compressive strength≥6MPa, water absorption more than 4%.

[0032] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for producing high-strength foamed ceramics, characterized by, The application relates to a method for preparing high-strength foamed ceramics. The method comprises the following steps: S1, grinding lithium mica tailings, combustion-supporting agent sodium tetraborate and fly ash for a period of time and drying, then configuring first foaming powder according to the mass ratio of lithium mica tailings: combustion-supporting agent: fly ash=50-60:3:25-40; S2, transferring the first foaming powder into a ball mill, adding metal strips accounting for 25-35% of the mass of the first foaming powder, and stirring in the ball mill for a period of time to obtain second foaming powder; S3, mixing foaming agent powder and a solution for granulation to obtain foaming material, uniformly spraying and adding 2-5wt% of the foaming material to the surface of the second foaming powder, and then granulating the second foaming material to obtain a material to be fired; S4, compacting the material to be fired in a mold and firing at 1200-1300 DEG C to obtain high-strength foamed ceramics; 2. The method of claim 1, wherein, The metal strips are copper wires with a diameter of not more than 1mm and a length of not more than 1cm, and the adding amount is 30%; the stirring time is not less than 4h.

3. The method of claim 1, wherein, In step S1, the ball milling speed is 150-250r / min, the ball milling time is 4-8h, the drying temperature is 100-120 DEG C, and the drying time is 12-24h.

4. The method of claim 1, wherein, In step S3, the diameter of the foaming agent powder is not more than 5 microns; and the foaming agent powder is silicon carbide. In step S3, the ratio of the foaming agent powder to the solution for granulation is 2-5:

15.

5. High-strength foamed ceramics prepared by the method in any one of claims 1-4.

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