Preparation method for high-performance foam ceramic and product prepared therefrom

Abstract

Disclosed in the present invention are a preparation method for a high-performance foam ceramic and a product prepared therefrom. By introducing dolomite, lithium slag, and copper tailings as raw materials, the firing temperature of the foam ceramic is effectively reduced, promoting the formation of a crystal structure having diopside, feldspar and quartz as main crystal phases as well as a composite closed-pore system in the foam ceramic during sintering. The unique structure and system of the present invention not only significantly enhance the flexural strength of the foam ceramic, ensuring the structural stability thereof, but also effectively maintain the high-porosity characteristics of the material, thereby realizing the dual optimization of mechanical properties and porous properties. The present invention can not only effectively reduce the firing temperature, but also has a positive promoting effect on improving resource utilization efficiency and environmental protection.

Description

A method for preparing high-performance foam ceramics and the product obtained therefrom Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a method for preparing high-performance foam ceramics and the product obtained therefrom. Background Technology

[0002] Foam ceramics, as a novel porous material, possess characteristics such as high specific surface area, low thermal conductivity, excellent filtration and adsorption capabilities, outstanding chemical stability, and thermal shock resistance. These properties give foam ceramics broad application potential in many fields, including construction and automobiles. With the deepening implementation of the "dual carbon" policy, the foam ceramics industry has also ushered in new development opportunities. By using low-cost minerals and solid waste as production raw materials, the firing temperature of foam ceramics is effectively reduced. This not only effectively promotes resource recycling and reduces carbon emissions but also significantly reduces the negative environmental impact of waste. This measure not only aligns with the national macro-strategy of energy conservation, emission reduction, and dual carbon policies but also brings both economic and social benefits to enterprises. However, the key issue that urgently needs to be addressed is how to efficiently utilize these low-cost raw materials to prepare high-performance foam ceramic materials, ensuring that they maintain high porosity while still possessing excellent flexural strength. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for preparing high-performance foam ceramics. By introducing dolomite, lithium slag, and copper tailings as raw materials, the firing temperature of the foam ceramics is effectively reduced. This promotes the formation of a crystal structure and a composite closed-pore system with diopside, anorthite, and quartz as the main crystalline phases during the sintering process. This ensures structural stability while effectively maintaining the high porosity of the material, thereby achieving dual optimization of mechanical and porosity properties. Another objective of this invention is to provide products obtained using the above-described preparation method.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] This invention provides a method for preparing high-performance foam ceramics. The raw material composition of the foam ceramics is 38-52 wt% shale, 12.2-17.9 wt% dolomite, 20-23 wt% lithium slag, 15-20 wt% copper tailings, and 0.8-1.1 wt% silicon carbide. The preparation method includes the following steps:

[0006] (1) After mixing the raw materials according to the above-mentioned composition ratio, the mixture is wet-milled and sieved to obtain foam ceramic slurry;

[0007] (2) The foam ceramic slurry is dried, ground and sieved to obtain foam ceramic powder;

[0008] (3) The blank obtained by pressing the foam ceramic powder is heated to 1080-1110℃ at a rate of 4-7℃ / min for sintering treatment, and the holding time is 1-2h. After natural cooling, high-performance foam ceramic is obtained.

[0009] Further, the chemical composition of the lithium slag of the present invention is SiO2 67.56-81.27 wt%, Al2O3 6.13-13.25 wt%, Fe2O3 0.05-0.21 wt%, Na2O 0.98-3.27 wt%, K2O 0.86-3.12 wt%, and L 7.38-13.98 wt%; the chemical composition of the copper tailings is SiO2 26.16-30.51 wt%, Al2O3 2.54-6.32 wt%, CaO 3.18-7.36 wt%, Fe2O3 38.56-56.27 wt%, MgO 2.86-6.98 wt%, Na2O 0.56-2.19 wt%, K2O 0.35-1.52 wt%, and ZnO 0. 0.46~2.13wt%, CuO 1.96~6.72wt%, IL 1.13~3.58wt%.

[0010] In the above scheme, in step (1) of the present invention, ball milling is performed according to the ratio of material:ball:water = 1:2 to 3:1 to 2, and the ball milling time is 30 to 40 minutes. In step (2), the drying temperature is 90 to 100°C, and the drying time is 7 to 10 hours. In step (3), the pressing pressure is 6 to 9 MPa.

[0011] The product prepared using the above-described method for high-performance foam ceramics has diopside, anorthite, and quartz as its main crystalline phases, and exhibits a flexural strength of 10.78–13.02 MPa and a bulk density of 0.81–0.95 g / cm³. 3 The total porosity is 60.89–64.56%, and the closed porosity is 51.24–56.73%.

[0012] The present invention has the following beneficial effects:

[0013] (1) The dolomite introduced in the formulation system of this invention gradually and slowly releases CO2 gas during high-temperature calcination, forming pores with small pore size and uniform distribution inside the foam ceramic; while SiC reacts at high temperature, forming pores with larger pore size. The two intertwine to form a composite closed-pore system. In addition, Al2O3 can increase the melting temperature and viscosity characteristics of the liquid phase, control the bubble size, enhance the liquid phase's ability to retain gas, and make the pore wall structure more compact, further optimizing the uniformity and stability of the closed-pore structure. The synergistic effect of dolomite, SiC, and Al2O3 in the calcination process of this invention jointly promotes the formation of the composite closed-pore structure, which endows the foam ceramic of this invention with high porosity and uniform distribution.

[0014] (2) The addition of dolomite, lithium slag, and copper tailings in this invention results in a relatively high content of calcium and magnesium in the system, which will form diopside (CaO·MgO·2SiO2) under high-temperature calcination. However, calcium is relatively excessive. During the formation of diopside, the excess calcium will combine with Al2O3 and SiO2 in the system to form anorthite (CaO·Al2O3·2SiO2). Diopside, anorthite, and the residual quartz crystal phase together constitute the main crystalline phase of the foam ceramic, effectively enhancing the flexural strength of the foam ceramic. The crystal structure and composite closed-pore system of the foam ceramic of this invention not only ensure its structural stability but also effectively maintain the high porosity of the material, thereby achieving dual optimization of mechanical properties and porous properties.

[0015] (3) The lithium slag and copper tailings of this invention are solid wastes, and shale is a low-cost raw material. The copper tailings have a high Fe2O3 content, and the dolomite has high CaO and MgO content. The shale and lithium slag contain alkali metal and alkaline earth metal oxides, thus forming an Fe-Ca-Mg-K-Na composite fluxing system, which helps the product to foam uniformly. Using this formulation system to prepare foam ceramics not only effectively reduces the firing temperature but also has a positive promoting effect on improving resource utilization efficiency and environmental protection. Attached Figure Description

[0016] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings:

[0017] Figure 1 is an industrial CT image (a: cross-sectional view; b: perspective view) of the foam ceramic prepared according to an embodiment of the present invention. Detailed Implementation

[0018] This invention implements a method for preparing high-performance foam ceramics. The raw material composition of the foam ceramics is 38-52 wt% shale, 12.2-17.9 wt% dolomite, 20-23 wt% lithium slag, 15-20 wt% copper tailings, and 0.8-1.1 wt% silicon carbide. The chemical composition of the raw materials used is shown in Table 1, and the raw material composition of each embodiment is shown in Table 2.

[0019] The preparation method has the following steps:

[0020] (1) After mixing the raw materials according to the above composition ratio, the mixture is ball-milled according to the ratio of material:ball:water = 1:2~3:1~2 for 30~40 minutes. The mixture is then passed through a 60-mesh sieve to obtain foam ceramic slurry.

[0021] (2) The above foam ceramic slurry is placed in an oven at a temperature of 90-100℃ and dried for 7-10 hours. After grinding and passing through a 200-mesh sieve, foam ceramic powder is obtained.

[0022] (3) Press the above foam ceramic powder under a pressure of 6-9 MPa for 25 seconds. Place the resulting blank in an electric furnace and heat it to 1080-1110℃ at a rate of 4-7℃ / min for sintering. Hold it for 1-2 hours. After natural cooling, high-performance foam ceramic is obtained.

[0023] The process parameters for each embodiment are shown in Table 3.

[0024] Table 1. Chemical composition (wt%) of raw materials used in the embodiments of the present invention.

[0025] Table 2. Raw material composition (wt%) of various embodiments of the present invention

[0026] Table 3 Process parameters of various embodiments of the present invention

[0027] Comparative Example 1:

[0028] Four sets of experiments were conducted with no dolomite added as the first control, and the other conditions were the same as in Examples 1, 2, 3, and 4.

[0029] Comparative Example 2:

[0030] Four sets of experiments were conducted with no lithium slag added as the control example, and the other conditions were the same as those in Example 1, Example 2, Example 3, and Example 4.

[0031] Comparative Example 3:

[0032] Four sets of experiments were conducted with no copper tailings added as the control example, and the other conditions were the same as in Examples 1, 2, 3 and 4.

[0033] Performance testing:

[0034] As shown in Figure 1, the foam ceramic prepared in this embodiment of the invention has a composite closed-pore structure. The flexural strength was determined according to GB / T17657-2013 (three-point bending method for static bending strength); the bulk density, total porosity, and closed-pore ratio were determined according to GB / T 2997-2000. The performance indicators of the foam ceramic prepared in this embodiment of the invention, and the average performance indicators of the foam ceramics obtained in the comparative examples, are shown in Table 4.

[0035] Table 4 Performance indicators of foam ceramics in various embodiments and comparative examples of the present invention

Claims

1. A method of making high performance ceramic foams, characterized by: The raw material composition of the foam ceramic is 38-52 wt% shale, 12.2-17.9 wt% dolomite, 20-23 wt% lithium slag, 15-20 wt% copper tailings, and 0.8-1.1 wt% silicon carbide; The preparation method includes the following steps: (1) After mixing the raw materials according to the above-mentioned composition ratio, the mixture is wet-milled and sieved to obtain foam ceramic slurry; (2) The foam ceramic slurry is dried, ground and sieved to obtain foam ceramic powder; (3) The blank obtained by pressing the foam ceramic powder is heated to 1080-1110℃ at a rate of 4-7℃ / min for sintering treatment, and the holding time is 1-2h. After natural cooling, high-performance foam ceramic is obtained.

2. The method of claim 1, wherein: The chemical composition of the lithium slag is 67.56–81.27 wt% SiO2, 6.13–13.25 wt% Al2O3, 0.05–0.21 wt% Fe2O3, 0.98–3.27 wt% Na2O, 0.86–3.12 wt% K2O, and 7.38–13.98 wt% Il.

3. The method of claim 1, wherein: The chemical composition of the copper tailings is as follows: SiO2 26.16–30.51 wt%, Al2O3 2.54–6.32 wt%, CaO 3.18–7.36 wt%, Fe2O3 38.56–56.27 wt%, MgO 2.86–6.98 wt%, Na2O 0.56–2.19 wt%, K2O 0.35–1.52 wt%, ZnO 0.46–2.13 wt%, CuO 1.96–6.72 wt%, and I1 wt%.

4. The method of claim 1, wherein: In step (1), ball milling is performed according to the ratio of material:ball:water = 1:2 to 3:1 to 2, and the ball milling time is 30 to 40 minutes.

5. The method of claim 1, wherein: In step (2), the drying temperature is 90-100℃ and the drying time is 7-10h.

6. The method of claim 1, wherein: The pressing pressure in step (3) is 6-9 MPa.

7. Product obtained by the process for the production of high-performance foamed ceramics according to one of claims 1 to 6, characterized in that: The main crystalline phases of the high-performance foam ceramic are diopside, anorthite, and quartz.

8. The product of claim 7, wherein: The high-performance foam ceramic has a bending strength of 10.78-13.02 MPa, a bulk density of 0.81-0.95 g / cm 3 , a total porosity of 60.89-64.56%, and a closed porosity of 51.24-56.73%.

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