Mud and carbide slag based light weight ceramic tile and its preparation method

Abstract

The application discloses a kind of silt and carbide slag-based light-weight ceramic brick and preparation method thereof.The preparation method includes the following steps: silt and carbide slag powder after drying are mixed uniformly, to obtain mixed material;The mixed material is pressed into shape, to obtain green body;The green body is high-temperature calcined, to obtain silt and carbide slag-based light-weight ceramic brick.The application uses silt and carbide slag as raw material to prepare ceramic brick, so that the elements in the two raw materials are complementary, compared with the ceramic brick prepared by using pure silt, the strength is improved, and a new direction is provided for the comprehensive utilization of two kinds of bulk solid waste;The application has the characteristics of simple process, low cost and environmental friendliness;The prepared silt carbide slag-based ceramic brick has high compressive strength, and the alkaline environment formed by carbide slag has good solidification effect on heavy metal ions, solving the problems of adverse effects of humus on strength, high density of calcined products and large consumption of natural resources in the ceramic brick manufacturing process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of baking ceramic bricks, in particular to a silt and carbide slag-based light ceramic brick and a preparation method thereof. BACKGROUND

[0002] Ceramic bricks are an important building material. Due to their low apparent density, more pores and high mechanical properties, ceramic bricks have the characteristics of light weight, corrosion resistance, frost resistance, shock resistance and heat insulation. At the same time, due to the rough and porous surface, ceramic bricks are widely used in water treatment, sound absorption materials and other aspects. However, the main production raw materials of ceramic bricks, clay and shale, are non-renewable resources, which have been prohibited or restricted from mining.

[0003] The main components of silt are SiO2 and Al2O3, and it also contains a certain amount of Na2O, K2O, CaO, MgO, Fe2O3 and other fluxing oxide components, which are very similar to the components of ceramic brick raw materials, and have the possibility of resource preparation of ceramic bricks. Using silt as a solid waste to replace non-renewable resources to prepare ceramic bricks is beneficial to reduce the dependence on non-renewable resources.

[0004] Although silt-based ceramic bricks have emerged in the market due to their advantages, there are still some shortcomings when they are used in engineering construction. The unique structure of humic acid released by organic matter in silt is easy to react with metal salts and ion exchange neutralization reaction, which can erode the solidified silt soil and affect the strength of ceramic bricks. Therefore, the large-scale application of silt-based ceramic bricks is still limited. SUMMARY

[0005] The present application aims to overcome the above technical deficiencies and provide a silt and carbide slag-based light ceramic brick and a preparation method thereof, which solves the technical problem of low compressive strength of ceramic bricks prepared by sintering silt in the prior art.

[0006] In a first aspect, the present application provides a preparation method of a silt and carbide slag-based light ceramic brick, comprising the following steps:

[0007] Mixing the dried silt and carbide slag powder uniformly to obtain a mixture;

[0008] Pressing the mixture to form a green body;

[0009] Sintering the green body at high temperature to obtain a silt and carbide slag-based light ceramic brick.

[0010] In a second aspect, the present application provides a silt and carbide slag-based light ceramic brick, which is obtained by the preparation method of the silt and carbide slag-based light ceramic brick provided in the first aspect of the present application.

[0011] Compared with the prior art, the present application has the following advantages:

[0012] The present application uses silt and carbide slag as raw materials to prepare ceramic bricks, so that the elements in the two raw materials are complementary, compared with the ceramic bricks prepared by using pure silt, the strength is improved, and at the same time, a new direction for the comprehensive utilization of two kinds of bulk solid wastes is provided; the present application has the characteristics of simple process, low cost and environmental friendliness; the prepared silt and carbide slag based ceramic brick has high compressive strength, and the alkaline environment formed by the carbide slag has good solidification effect on heavy metal ions, solving the problems of adverse effects of humus on strength, high density of calcined products, large consumption of natural resources and the like in the ceramic brick manufacturing process. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0014] In a first aspect, the present application provides a preparation method of silt and carbide slag based light ceramic brick, comprising the following steps:

[0015] S1, mixing the dried silt and carbide slag powder uniformly to obtain a mixture;

[0016] S2, pressing and forming the mixture to obtain a green body;

[0017] S3, high-temperature calcining the green body to obtain a silt and carbide slag based light ceramic brick.

[0018] Carbide slag is the waste slag discharged when producing acetylene gas by using calcium carbide (main component is CaCO3). The main components of the waste slag are Ca(OH)2 and H2O, the content of CaO is about 86% to 87%, and the content of MgO is about 5% to 6%. The present application uses silt and carbide slag as raw materials to prepare ceramic bricks, effectively neutralizes the humic acid released by the organic matter through the use of carbide slag, thereby delaying the erosion of the solidified soil, improving the strength, and solving the adverse effects of humic acid; at the same time, the high content of humus in the silt is used, and under high temperature conditions, the CaO in the carbide slag is fluxed, and internal oxidation reaction occurs with iron oxide and gas-forming substances such as carbon, to produce water vapor, CO2, CO and H2, etc., thereby forming small and closed pores inside, so that the prepared ceramic bricks have good expansion performance. A certain number of excellent pores are formed inside the ceramic bricks, which not only guarantee the strength of the ceramic bricks, but also reduce the density of the ceramic bricks; in addition, the present application uses the fluxing oxide components such as Na2O, K2O, CaO, MgO and Fe2O3 contained in the silt to help the conversion of the halloysite in the carbide slag into liquid amorphous SiO2 to wrap solid particles, form a basic skeleton with compact structure and complete surface, and increase the macroscopic strength of the ceramic bricks. + The present application uses the silt and carbide slag as raw materials to prepare ceramic bricks, effectively neutralizes the humic acid released by the organic matter through the use of carbide slag, thereby delaying the erosion of the solidified soil, improving the strength, and solving the adverse effects of humic acid; at the same time, the high content of humus in the silt is used, and under high temperature conditions, the CaO in the carbide slag is fluxed, and internal oxidation reaction occurs with iron oxide and gas-forming substances such as carbon, to produce water vapor, CO2, CO and H2, etc., thereby forming small and closed pores inside, so that the prepared ceramic bricks have good expansion performance. A certain number of excellent pores are formed inside the ceramic bricks, which not only guarantee the strength of the ceramic bricks, but also reduce the density of the ceramic bricks; in addition, the present application uses the fluxing oxide components such as Na2O, K2O, CaO, MgO and Fe2O3 contained in the silt to help the conversion of the halloysite in the carbide slag into liquid amorphous SiO2 to wrap solid particles, form a basic skeleton with compact structure and complete surface, and increase the macroscopic strength of the ceramic bricks.

[0019] The prior art ceramic brick preparation process is usually based on wet or semi-dry green body and needs certain binder and additive. However, the present application creatively proposes to form by pressing based on dry green body without any additive. This makes the friction and contact force between particles larger, the mechanical bite effect between particles stronger, the green body compactness after forming higher, and the adhesion between particles stronger, which is beneficial to the subsequent liquid phase amorphous SiO2 tightly wrapping the solid particles, thereby improving the compressive strength of the final product.

[0020] In the present application, the silt and carbide slag-based light ceramic brick is made of the following raw materials by weight: 5-20 parts of carbide slag and 80-95 parts of silt.

[0021] In the present application, the mass ratio of silt to carbide slag is 1:(8-10). Within this mass ratio range, the obtained silt and carbide slag-based light ceramic brick has higher compressive strength. Preferably, it is 1:(8.45-9.45), more preferably 1:(8.75-9.15), and more preferably 1:(8.9-9.05).

[0022] In some more preferred embodiments of the present application, the above-mentioned silt and carbide slag-based light ceramic brick is made of the following raw materials by weight: 10 parts of carbide slag and 90 parts of silt.

[0023] In the present application, the particle size D50 of silt is 5-50 μm, and the main chemical components have the following mass percentages: SiO2 50%-70%, Al2O3 15%-30%, Fe2O3 5%-10%, CaO 0%-3%, and MgO 0%-3%. After drying, the water content is 5%-10%.

[0024] In the present application, the particle size D50 of carbide slag is 5-10 μm, and the main chemical components have the following mass percentages: CaO 30%-50%, SiO2 30%-50%, Al2O3 5%-15%, K2O 0%-3%, Na2O 0%-3%, and Fe2O3 0%-3%. After drying, the water content is 5%-10%.

[0025] In the present application, the forming pressure in the process of pressing forming is 1-5 MPa, preferably 2-3 MPa, and more preferably 2.56 MPa.

[0026] In the present application, the calcination temperature is 1000-1200℃, preferably 1050-1100℃, more preferably 1100℃, the calcination time is 30-50min, preferably 40min, and the heating rate is 2-5℃ / min, preferably 4℃ / min. The mineral components in the sludge, such as illite, montmorillonite, zeolite, chlorite, etc., are effective minerals for swelling. The present application can improve the burning temperature resistance of the ceramic brick by combining the above special pressing forming process, so that the sludge can be calcined into a ceramic brick at a higher temperature, thereby converting the hydrophilic minerals such as montmorillonite into needle-like mullite crystals to improve the strength, and promoting the organic matter as a gas generating agent to make the ceramic brick lightweight.

[0027] In a second aspect, the present application provides a sludge and carbide slag-based lightweight ceramic brick, which is obtained by the preparation method of the sludge and carbide slag-based lightweight ceramic brick provided in the first aspect of the present application.

[0028] Example 1

[0029] Step one: place the sludge and carbide slag in an oven and dry until the mass no longer changes, and then cool to room temperature to obtain dried sludge and carbide slag.

[0030] Step two: mix and stir 10 parts of carbide slag and 90 parts of sludge for 20min to obtain a solid mixture.

[0031] Step three: place the solid mixture into a tablet press and press into a cylinder with a diameter of 4cm and a height of 2cm at a pressure of 2.56MPa.

[0032] Step four: place the cylinder into a calcination furnace and calcine at a calcination temperature of 1100℃ for 40min, with a heating rate of 4℃ / min.

[0033] The ceramic brick obtained by the method has a compressive strength value of 25.935MPa.

[0034] Example 2

[0035] Step one: place the sludge and carbide slag in an oven and dry until the mass no longer changes, and then cool to room temperature to obtain dried sludge and carbide slag.

[0036] Step two: mix and stir 5 parts of carbide slag and 95 parts of sludge for 20min to obtain a solid mixture.

[0037] Step three: place the solid mixture into a tablet press and press into a cylinder with a diameter of 4cm and a height of 2cm at a pressure of 2.56MPa.

[0038] Step four: place the cylinder into a calcination furnace and calcine at a calcination temperature of 1100℃ for 40min, with a heating rate of 4℃ / min.

[0039] The compressive strength value of the ceramic brick obtained by the method is 10.987 MPa.

[0040] Example 3

[0041] Step one: put the silt and carbide slag in the oven, and bake until the mass does not change, and then cool to room temperature to obtain dried silt and carbide slag.

[0042] Step two: mix and stir 20 parts of carbide slag and 80 parts of silt for 20 minutes to obtain a solid mixture;

[0043] Step three: put the solid mixture into a tablet press to press into a cylinder with a diameter of 4 cm and a height of 2 cm at a pressure of 2.56 MPa.

[0044] Step four: put the cylinder into a calcining furnace and calcine at a calcining temperature of 1100℃ for 40 minutes, with a heating rate of 4℃ / min.

[0045] The compressive strength value of the ceramic brick obtained by the method is 6.600 MPa.

[0046] Comparative Example 1

[0047] In step two of Example 1, replace "10 parts of carbide slag, 90 parts of silt" with "8 parts of carbide slag, 72 parts of silt and 20 parts of water", and the remaining steps are the same as Example 1.

[0048] The compressive strength value of the ceramic brick obtained in Comparative Example 1 is 9.232 MPa, which is about 16.703 MPa lower than that of Example 1. The reason is that the hydroxyl functional group in water is the main microstructure that affects the finished ceramic brick, and it is also one of the main functional groups that affect the compressive strength of the finished ceramic brick. After the step of adding water, a large number of hydroxyl functional groups are added, making it difficult for halloysite to be converted into liquid amorphous SiO2, thus reducing the compressive strength of the finished ceramic brick, and the vibration of the hydroxyl functional group is not conducive to the maintenance of the skeleton strength of the finished ceramic brick.

[0049] Comparative Example 2

[0050] In step two of Example 1, replace "10 parts of carbide slag, 90 parts of silt" with "100 parts of silt", and the remaining steps are the same as Example 1.

[0051] The compressive strength of the ceramic bricks obtained in Comparative Example 2 was 9.85 MPa, which was about 16.085 MPa lower than that in Example 1. This is because the Ca(OH)2 in the raw material carbide slag provides an alkaline environment for the reaction. The alkaline environment has a strong promoting effect on the reaction between carbide slag and sludge. Furthermore, halloysite in the sludge is more likely to be converted into SiO2 under alkaline conditions, thereby promoting the formation of liquid-phase amorphous SiO2 and thus increasing the compressive strength of the ceramic bricks.

[0052] Comparative Example 3

[0053] In step two of Example 1, "10 parts calcium carbide slag and 90 parts silt" are changed to "25 parts calcium carbide slag and 75 parts silt", and the remaining steps are the same as in Example 1.

[0054] The compressive strength of the ceramic bricks obtained in Comparative Example 3 was 4.281 MPa, which was approximately 21.654 MPa lower than that in Example 1. This is because the raw material, calcium carbide slag, is rich in Ca(OH)₂. When an excessive amount of calcium carbide slag is added, the proportion of SiO₂ in the mixture decreases, leading to CaO accumulation. CaO adheres to the surface of the SiO₂ basic framework rather than filling the gaps within the SiO₂ basic framework, causing the SiO₂ framework to break down and its strength to decrease.

[0055] Comparative Example 4

[0056] Change the roasting temperature "1100℃" in step four of Example 1 to "1000℃".

[0057] The ceramic bricks obtained in Comparative Example 4 were broken and misshapen. The reason is that when the temperature is too low, halloysite in the carbide slag cannot be transformed into liquid-phase amorphous SiO2 to encapsulate solid particles. The SiO2 skeleton is broken, and the solid particles are stacked in a particle-like state. They cannot react with Al2O3 to form an Al-O-Si structure. At the same time, the aliphatic CH structure in the ceramic bricks is less eliminated, so the ceramic bricks are broken and misshapen.

[0058] Comparative Example 5

[0059] Change the roasting temperature "1100℃" in step four of Example 1 to "1050℃".

[0060] The compressive strength of the ceramic bricks obtained in Comparative Example 5 was 12.094 MPa, which was approximately 13.841 MPa lower than that in Example 1. This is because, at excessively low temperatures, halloysite in the carbide slag cannot be sufficiently converted into liquid-phase amorphous SiO2 to encapsulate solid particles; instead, it mostly remains in a particle-stacked state, making it difficult to react extensively with Al2O3 to form an Al-O-Si structure. Simultaneously, the aliphatic CH structure cannot be completely eliminated, thus reducing strength.

[0061] Comparative Example 6

[0062] Change the roasting temperature "1100℃" in step four of Example 1 to "1200℃".

[0063] The compressive strength of the ceramic brick obtained in Comparative Example 6 was 11.652 MPa, which was about 14.283 MPa lower than that in Example 1. The reason for this is that when the temperature is too high, the aliphatic CH structure decomposes at high temperature, generating a large amount of expanding gas that escapes strongly outward in a short time, thus forming continuous pores, making the resulting ceramic brick structure loose and reducing its macroscopic strength.

[0064] Comparative Example 7

[0065] Change the heat preservation time "40min" in step four of Example 1 to "30min".

[0066] The compressive strength of the ceramic bricks obtained in Comparative Example 7 was 14.257 MPa, which was approximately 11.678 MPa lower than that in Example 1. This is because, with a short heat preservation time, the formed liquid-phase amorphous SiO2 was insufficient to fully encapsulate the material spheres.

[0067] Comparative Example 8

[0068] Change the heat preservation time in step four of Example 1 from "40 min" to "50 min".

[0069] The compressive strength of the ceramic brick obtained in Comparative Example 8 was 13.987 MPa, which was about 11.948 MPa lower than that in Example 6. This is because the heat preservation time was too long, and the skeleton structure formed by the liquid-phase amorphous SiO2 and CaO was dissolved and destroyed, which was detrimental to the macroscopic compressive strength of the ceramic brick.

[0070] Compared with the prior art, the beneficial effects of the present invention also include:

[0071] (1) Under optimal firing conditions, the compressive strength of this invention can reach up to 25.935 MPa, which meets the MU25 strength grade specified in the national standard GB5101-2003 "Sintered Common Bricks". The prepared samples have the characteristics of smooth surface and light weight, which is beneficial for applications in building exterior walls, traffic and road barriers, and building material preparation.

[0072] (2) The product made by the present invention not only makes the maximum use of the value of solid waste, but also solves the shortcomings of previous ceramic brick products such as easy cracking and lack of frost resistance to a certain extent. It is of great significance in terms of economy, practicality and environmental protection.

[0073] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing lightweight ceramic bricks based on sludge and carbide slag, characterized in that, Includes the following steps: The dried sludge and calcium carbide slag powder are mixed evenly to obtain a mixture; The mixture is pressed into a blank to obtain a green body; The green body is fired at high temperature to obtain lightweight ceramic bricks based on silt and carbide slag; wherein... The silt and carbide slag-based lightweight ceramic bricks are made from the following raw materials in parts by weight: 10 parts carbide slag and 90 parts silt. The particle size D50 of the silt is 5–50 µm; The particle size D50 of the carbide slag is 5-10 µm; The silt and carbide slag, after being dried, have a moisture content of 5% to 10%. During the high-temperature roasting process, the roasting temperature is 1100℃, the roasting time is 40min, and the heating rate is 2~5℃ / min.

2. The method for preparing lightweight ceramic bricks based on sludge and carbide slag according to claim 1, characterized in that, During the pressing process, the forming pressure is 1-5 MPa.

3. A lightweight ceramic brick based on silt and carbide slag, characterized in that, The silt and carbide slag-based lightweight ceramic bricks are obtained by the preparation method of silt and carbide slag-based lightweight ceramic bricks according to any one of claims 1 to 2.