Preparation method of high-performance foamed ceramic and product prepared by preparation method

Abstract

According to the preparation method of the high-performance foamed ceramic and the prepared product, dolomite, lithium slag and copper tailings are introduced as raw materials, so that the firing temperature of the foamed ceramic is effectively reduced; a crystal structure with diopside, anorthite and quartz as main crystal phases and a composite closed pore system are formed in the sintering process of the foamed ceramic. According to the unique structure and system, the breaking strength of the foamed ceramic is remarkably enhanced, the structural stability of the foamed ceramic is ensured, and the high porosity characteristic of the material is effectively maintained, so that double optimization of mechanical properties and porous properties is realized. The method not only can effectively reduce the firing temperature, but also has a positive promotion effect on improvement of the resource utilization efficiency and environmental protection.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic materials, and in particular to a preparation method of high-performance foam ceramics and a product obtained therefrom. Background Art

[0002] As a new type of porous material, foam ceramics have the characteristics of high specific surface area, low thermal conductivity, good filtration and adsorption capacity, excellent chemical stability and thermal shock resistance. These characteristics make foam ceramics have broad application potential in many fields such as construction and automobiles. By using low-cost minerals and solid waste as production raw materials, the firing temperature of foam ceramics is effectively reduced, which can not only effectively promote the recycling of resources and reduce carbon emissions, but also significantly reduce the negative impact of waste on the environment. However, the key problem that needs to be solved urgently is how to efficiently use these low-cost raw materials to prepare high-performance foam ceramic materials to ensure that they have excellent flexural strength while maintaining high porosity characteristics. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing high-performance foam ceramics. By introducing dolomite, lithium slag and copper tailings as raw materials, the sintering temperature of the foam ceramics is effectively reduced, and the foam ceramics are prompted to form a crystal structure and a composite closed pore system with diopside, anorthite and quartz as the main crystal phases during the sintering process, so that while ensuring the structural stability, the high porosity characteristics of the material are effectively maintained, thereby achieving dual optimization of mechanical properties and porous properties. Another purpose of the present invention is to provide a product prepared by the above preparation method.

[0004] The purpose of the present invention is achieved through the following technical solutions:

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

[0006] (1) mixing the raw materials according to the composition ratio, wet ball milling and sieving to obtain a foam ceramic slurry;

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

[0008] (3) The green body obtained by pressing the foam ceramic powder into shape is heated to 1080-1110° C. at a rate of 4-7° C. / min for sintering, and the heat preservation time is 1-2 hours. After natural cooling, high-performance foam ceramics are obtained.

[0009] Furthermore, the chemical composition of the lithium slag of the present invention is SiO 2 67.56~81.27wt%、Al 2 O 3 6.13~13.25wt%,Fe 2 O 3 0.05~0.21wt%、Na 2 O 0.98~3.27wt%, K 2 O 0.86~3.12wt%, IL 7.38~13.98wt%; the chemical composition of the copper tailings is SiO 2 26.16~30.51wt%、Al 2 O 3 2.54~6.32wt%, CaO3.18~7.36wt%, Fe 2 O 3 38.56~56.27wt%, MgO 2.86~6.98wt%, Na 2 O 0.56~2.19wt%、K 2 O 0.35~1.52wt%, ZnO 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, the ball milling treatment is carried out according to the ratio of material: ball: water = 1: 2-3: 1-2, and the ball milling time is 30-40 minutes. In step (2), the drying temperature is 90-100° C. and the drying time is 7-10 hours. In step (3), the pressure of the pressing molding is 6-9 MPa.

[0011] The product prepared by the above-mentioned preparation method of high-performance foam ceramics has a main crystal phase of diopside, anorthite and quartz, a flexural strength of 10.78-13.02 MPa, and a bulk density of 0.81-0.95 g / cm 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 into the formulation system of the present invention gradually and slowly releases CO during high-temperature calcination. 2 Gas forms pores with smaller pores and uniform distribution inside the foam ceramic; while SiC reacts at high temperature to form pores with larger pores. The two are intertwined to form a composite closed pore system. 2 O3 It can improve the melting temperature and viscosity characteristics of the liquid phase, control the size of bubbles, enhance the gas sealing ability of the liquid phase, make the pore wall structure denser, and further optimize the uniformity and stability of the closed pore structure. 2 O 3 The synergistic effect during the calcination process jointly promotes the formation of a composite closed-pore structure, which gives the foam ceramic of the present invention the characteristics of high porosity and uniform distribution.

[0014] (2) The addition of dolomite, lithium slag and copper tailings in the present invention makes the content of calcium and magnesium in the system relatively high, and diopside (CaO·MgO·2SiO 2 ). However, calcium is relatively excessive. In the process of forming diopside, the excess calcium will react with Al in the system. 2 O 3 and SiO 2 Combined to form calcium feldspar (CaO·Al 2 O 3 ·2SiO 2 ). Diopside, anorthite and residual quartz crystal phase together constitute the main crystal phase of foam ceramics, which effectively enhances the flexural strength of foam ceramics. The crystal structure and composite closed pore system of the foam ceramics of the present invention not only ensure the structural stability, but also effectively maintain the high porosity characteristics of the material, thereby achieving dual optimization of mechanical properties and porous properties.

[0015] (3) The lithium slag and copper tailings of the present invention are solid wastes, shale is a low-cost raw material, and the Fe 2 O 3 The content is high. Dolomite has high CaO and MgO content. Shale and lithium slag contain alkali metal and alkaline earth metal oxides, thus forming a Fe-Ca-Mg-K-Na composite flux system, which helps the product to foam evenly. The use of this formula system to prepare foam ceramics can not only effectively reduce the firing temperature, but also has a positive role in improving resource utilization efficiency and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 1 The industrial CT images of the foam ceramics prepared in the embodiment of the present invention are shown in FIG. 1 (a: cross-sectional view; b: stereoscopic view). DETAILED DESCRIPTION

[0018] The present invention implements a method for preparing a high-performance foam ceramic, wherein the raw material composition of the foam ceramic is 38-52wt% of shale, 12.2-17.9wt% of dolomite, 20-23wt% of lithium slag, 15-20wt% of copper tailings, and 0.8-1.1wt% of 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 raw material composition ratio, ball milling is performed at a ratio of material: ball: water = 1:2-3:1-2, the ball milling time is 30-40 minutes, and the mixture is passed through a 60-mesh sieve to obtain a foam ceramic slurry;

[0021] (2) placing the foam ceramic slurry in an oven at a temperature of 90 to 100° C. and drying it for 7 to 10 hours, grinding it, and passing it through a 200-mesh sieve to obtain a foam ceramic powder;

[0022] (3) The foam ceramic powder is pressed into shape at a pressure of 6 to 9 MPa for 25 seconds. The resulting green body is placed in an electric furnace and heated to 1080 to 1110° C. at a rate of 4 to 7° C. / min for sintering. The heat preservation time is 1 to 2 hours. After natural cooling, high-performance foam ceramics are obtained.

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

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

[0025]

[0026] Table 2 Raw material composition of each embodiment of the present invention (wt%)

[0027]

[0028] Table 3 Process parameters of various embodiments of the present invention

[0029]

[0030] Comparative Example 1:

[0031] Four groups of experiments were conducted with no dolomite added as comparative example 1, and other conditions were the same as those of example 1, example 2, example 3, and example 4.

[0032] Comparative Example 2:

[0033] Four groups of experiments were conducted with no lithium slag added as comparative example 2, and the other conditions were the same as those of example 1, example 2, example 3, and example 4.

[0034] Comparative Example 3:

[0035] Four groups of experiments were conducted with no copper tailings added as comparative example 3 and the other conditions being the same as those of examples 1, 2, 3 and 4.

[0036] Performance Test:

[0037] like Figure 1 As shown, the foam ceramics prepared in the embodiment of the present invention have a composite closed pore structure. The flexural strength was measured according to the standard GB / T17657-2013 (static bending strength measured by three-point bending method); the volume density, total porosity, and closed porosity were measured according to the standard GB / T 2997-2000. The performance indicators of the foam ceramics prepared in the embodiment of the present invention and the average performance indicators of the foam ceramics obtained in the comparative example are shown in Table 4.

[0038] Table 4 Performance indicators of foam ceramics in various embodiments of the present invention and comparative examples

[0039]

Claims

1. A method for preparing high-performance foam ceramics, characterized in that: The raw material composition of the foam ceramic is 38-52wt% of shale, 12.2-17.9wt% of dolomite, 20-23wt% of lithium slag, 15-20wt% of copper tailings, and 0.8-1.1wt% of silicon carbide; The preparation method comprises the following steps: (1) mixing the raw materials according to the composition ratio, wet ball milling and sieving to obtain a foam ceramic slurry; (2) The foam ceramic slurry is dried, ground, and sieved to obtain foam ceramic powder; (3) The green body obtained by pressing the foam ceramic powder into shape is heated to 1080-1110° C. at a rate of 4-7° C. / min for sintering, and the heat preservation time is 1-2 hours. After natural cooling, high-performance foam ceramics are obtained.

2. The method for preparing high-performance foam ceramics according to claim 1, characterized in that: The chemical composition of the lithium slag is SiO2 67.56-81.27wt%, Al2O3 6.13-13.25wt%, Fe2O3 0.05-0.21wt%, Na2O 0.98-3.27wt%, K2O 0.86-3.12wt%, IL 7.38-13.98wt%.

3. The method for preparing high-performance foam ceramics according to claim 1, characterized in that: The chemical composition of the copper tailings is SiO2 26.16-30.51wt%, Al2O3 2.54-6.32wt%, CaO 3.18-7.36wt%, Fe2O3 38.56-56.27wt%, MgO 2.86-6.98wt%, Na2O 0.56-2.19wt%, K2O 0.35-1.52wt%, ZnO 0.46-2.13wt%, CuO 1.96-6.72wt%, IL 1.13-3.58wt%.

4. The method for preparing high-performance foam ceramics according to claim 1, characterized in that: In the step (1), the ball milling treatment is carried out according to the ratio of material: ball: water = 1: 2-3: 1-2, and the ball milling time is 30-40 minutes.

5. The method for preparing high-performance foam ceramics according to claim 1, characterized in that: In the step (2), the drying temperature is 90-100° C. and the drying time is 7-10 hours.

6. The method for preparing high performance foam ceramics according to claim 1, characterized in that: The pressure of the compression molding in the step (3) is 6 to 9 MPa.

7. A product obtained by the method for preparing high-performance foam ceramics according to any one of claims 1 to 6, characterized in that: The main crystal phases of the high performance foam ceramic are diopside, anorthite and quartz.

8. The product according to claim 7, characterized in that: The high-performance foam ceramic has a flexural strength of 10.78-13.02 MPa and a bulk density of 0.81-0.95 g / cm 3 , the total porosity is 60.89~64.56%, and the closed porosity is 51.24~56.73%.

Images