Environment-friendly brick and preparation process thereof

Abstract

The application provides an environment-friendly brick and a preparation process thereof, wherein the environment-friendly brick comprises the following raw materials in parts by weight: 2-5 parts of sludge, 90-95 parts of construction waste, 0.1-0.3 parts of a composite sintering aid, and 0.5-1.2 parts of a plasticity adjusting agent. The composite sintering aid is composed of silicon nitride, starch, vegetable oil and sodium alginate. The plasticity adjusting agent is one or a combination of several of sodium palmitate, sodium stearate and sophoricoside. The environment-friendly brick is prepared through S1 raw material preparation, S2 raw material mixing and aging, S3 plasticity adjustment, S4 molding and cutting, and S5 drying and sintering. The application promotes complete combustion of the sludge by adding the composite sintering aid, thereby enhancing the performance of the brick body. By adding the plasticity adjusting agent and setting the plasticity adjusting link, the viscosity and fluidity of the material are adjusted according to the molding requirements of the brick body, the performance of the brick body is improved, and the molding defects are reduced.

Description

Technical Field

[0001] This invention relates to the field of environmentally friendly brick technology, specifically to an environmentally friendly brick and its preparation process. Background Technology

[0002] With the acceleration of urbanization, the construction and demolition of buildings have become increasingly frequent, generating a massive amount of construction waste. At the same time, industrial wastewater treatment and domestic wastewater processing also produce large quantities of sludge. Furthermore, dredging of riverbeds, lakebeds, and ponds, as well as mining activities, also generate substantial amounts of sludge, waste, and tailings. Currently, most of these wastes are disposed of through landfill, which not only occupies valuable land resources but also may cause secondary pollution to the land and environment, and even threaten human health. Faced with this serious situation, the disposal and resource utilization of construction waste and sludge are particularly urgent and necessary.

[0003] One existing approach to resource utilization is to turn construction waste and sludge into eco-friendly bricks. However, due to the high moisture or carbon content of the sludge, the bricks may not be fully sintered during the sintering process, thus affecting their strength. Furthermore, current methods for making eco-friendly bricks from construction waste and sludge do not adequately consider the plasticity of the materials, which can lead to cracks and deformation during molding, further impacting the bricks' strength. Summary of the Invention

[0004] In view of this, the present invention proposes an environmentally friendly brick and its preparation process to solve the above problems.

[0005] The technical solution of the present invention is implemented as follows: an environmentally friendly brick, comprising the following raw materials in parts by weight: 2-5 parts sludge, 90-95 parts construction waste, 0.1-0.3 parts composite sintering aid, and 0.5-1.2 parts plasticity modifier.

[0006] Furthermore, the composite sintering aid is composed of silicon nitride, starch, vegetable oil, and sodium alginate.

[0007] Furthermore, the plasticizer is one or a combination of sodium palmitate, sodium stearate, and sophora saponins.

[0008] Furthermore, the sludge is one or a combination of several of the following: industrial sludge, domestic sludge, organic sludge, and inorganic sludge, and the sludge moisture content is 40-80%.

[0009] Furthermore, construction waste includes mud, construction waste soil, construction slag, factory demolition slag, mining waste, mining waste soil, and tailings.

[0010] Furthermore, the mass-volume ratio of silicon nitride, starch, vegetable oil, and sodium alginate (g / mL) is (2-6):(1-5):(1-5):(1-3).

[0011] Furthermore, a process for preparing environmentally friendly bricks includes the following steps:

[0012] S1 Raw material preparation: The construction waste is crushed using a crusher to obtain construction waste particles with a diameter of 10-20mm; the construction waste particles are then ground in a grinder, and the resulting construction waste powder is passed through a 40-80 mesh sieve.

[0013] S2 Raw Material Mixing and Aging: Weigh out construction waste powder, sludge, and composite sintering aid by weight, mix and stir, and then age to obtain aged material.

[0014] S3 Plasticity Adjustment: Weigh out the plasticity adjuster by weight and add it to the aged material, stir and mix, and let it stand for plasticity adjustment.

[0015] S4 Forming and Cutting: After plasticity adjustment, the raw material is placed in a plastic soft extrusion blanking machine to extrude clay strips, which are then cut into wet blanks of product specifications by a CNC blanking machine.

[0016] S5 Drying and Sintering: The wet blanks are dried in a drying oven, and after drying, they are sintered in a tunnel kiln to obtain dry blanks; the dry blanks are cooled to room temperature to obtain environmentally friendly bricks.

[0017] Furthermore, the mixing speed in S2 is 100-300 r / min, the mixing time is 10-20 min, and the aging time is 48-72 h.

[0018] Furthermore, in S3, the stirring speed is 300-500 r / min, the stirring time is 5-10 min, and the settling time for plasticity adjustment is 20-40 min.

[0019] Furthermore, the moisture content of the wet blank in S4 is 15-25%.

[0020] Furthermore, the drying temperature in S5 is 120-150℃, the drying time is 6-8h, the sintering temperature is 950-1050℃, and the sintering time is 2-5h.

[0021] Furthermore, the moisture content of the dry blank in S5 is 2-4%, and the temperature decrease rate during cooling in S5 is 10-30℃ / min.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] This invention promotes complete sintering of sludge by adding a composite sintering aid. Silicon nitride in the composite sintering aid promotes heat transfer within the environmentally friendly brick body and accelerates moisture evaporation, thereby reducing the hindrance of water vapor in the sludge to the sintering reaction. Sodium alginate has good binding and dispersing properties. Adding sodium alginate improves the binding force of the sludge, making the sludge particles more tightly bound together, thus reducing the impact of moisture evaporation on the sintering reaction. During sintering, starch can react with carbon in the sludge to form stable compounds, thereby reducing the hindrance of carbon to the sintering reaction. Vegetable oil, rich in unsaturated fatty acids, acts as a lubricant during sintering, making it easier for sludge particles to slide and rearrange, promoting the sintering reaction and ensuring complete sintering of the sludge.

[0024] This invention enhances the plasticity of environmentally friendly bricks, improving their molding performance and strength by adding plasticity modifiers. Sodium stearate and sodium palmitate, when added to the brick-making raw materials, form a thin film on the surface, reducing friction and agglomeration between materials, making them easier to mix evenly. This facilitates better flow and filling of the mold during molding, thereby increasing the density and uniformity of the brick blank, and ultimately improving the molding performance and strength of the brick. Simultaneously, the long-chain hydrocarbon groups in the molecular structure of sodium stearate and sodium palmitate form bridging effects between raw material particles, increasing inter-particle adhesion. This increased adhesion allows the raw materials to deform and flow better under external forces, further improving the plasticity of the brick blank and thus enhancing its molding performance and strength. The addition of sophora japonica saponins also increases the viscosity of the raw materials, enabling them to better maintain their shape under external forces. This increased viscosity helps improve the plasticity of the brick blank, making it easier to deform and fill the mold during molding. At the same time, increased viscosity can reduce shrinkage and cracking of the brick blank during sintering, thereby improving the overall strength of the brick. Detailed Implementation

[0025] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0026] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0027] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0028] Example 1

[0029] An environmentally friendly brick comprises the following raw materials in parts by weight: 2 parts sludge, 90 parts construction waste, 0.1 parts a composite sintering aid composed of silicon nitride, starch, vegetable oil, and sodium alginate, and 0.5 parts a plasticizer. The plasticizer is sodium palmitate, the sludge is industrial sludge with a moisture content of 40%, and the construction waste is a combination of construction waste excavation soil and construction waste slag.

[0030] The mass-to-volume ratio of silicon nitride, starch, vegetable oil, and sodium alginate (g / mL) is 2:1:1:1.

[0031] Example 2

[0032] An environmentally friendly brick comprises the following raw materials in parts by weight: 5 parts sludge, 95 parts construction waste, 0.3 parts a composite sintering aid composed of silicon nitride, starch, vegetable oil, and sodium alginate, and 1.2 parts a plasticizer. The plasticizer is sophora japonica saponin, the sludge is domestic sewage sludge with a moisture content of 80%, and the construction waste is a combination of excavated soil and tailings from mining areas.

[0033] The mass-volume ratio of silicon nitride, starch, vegetable oil, and sodium alginate (g / mL) is 6:5:5:3.

[0034] Example 3

[0035] An environmentally friendly brick comprises the following raw materials in parts by weight: 3.5 parts sludge, 92.5 parts construction waste, 0.2 parts a composite sintering aid composed of silicon nitride, starch, vegetable oil, and sodium alginate, and 0.9 parts a plasticizer. The plasticizer is a combination of sodium palmitate and sophora japonica saponins in a molar ratio of 3:1. The sludge is a combination of industrial sludge and domestic sludge with a moisture content of 60%. The construction waste is a combination of construction waste excavation soil, construction waste slag, and tailings.

[0036] The mass-volume ratio of silicon nitride, starch, vegetable oil, and sodium alginate (g / mL) is 4:3:3:2.

[0037] The environmentally friendly bricks in Examples 1-3 above are prepared using the following process:

[0038] S1 Raw material preparation: The construction waste is crushed using a crusher to obtain construction waste particles with a diameter of 15mm; the construction waste particles are then ground in a grinder, and the resulting construction waste powder is passed through a 60-mesh sieve.

[0039] S2 Raw Material Mixing and Aging: Weigh out construction waste powder, sludge, and composite sintering aid by weight, mix and stir at 200 r / min for 15 min, and then age for 60 h to obtain aged material.

[0040] S3 Plasticity Adjustment: Weigh out the plasticity adjuster by weight and add it to the aged material. Stir and mix at 400 r / min for 7.5 min and let it stand for 30 min for plasticity adjustment.

[0041] S4 Forming and Cutting: After plasticity adjustment, the raw material is placed in a plastic soft extrusion blanking machine to extrude clay strips, which are then cut into wet blanks with a moisture content of 20% by a CNC blanking machine to product specifications.

[0042] S5 Drying and Sintering: The wet blanks are dried in a drying oven at 135°C for 7 hours. After drying, they are sintered in a tunnel kiln at 1000°C for 3.5 hours to obtain dry blanks with a moisture content of 3%. The dry blanks are cooled to room temperature at a temperature reduction rate of 20°C / min to obtain environmentally friendly bricks.

[0043] Example 4

[0044] This Example 4 uses the same raw material ratio as Example 3 and is prepared using the following process:

[0045] S1 Raw material preparation: The construction waste is crushed using a crusher to obtain construction waste particles with a diameter of 10mm; the construction waste particles are then placed in a grinder for grinding, and the resulting construction waste powder is then passed through a 40-mesh sieve.

[0046] S2 Raw Material Mixing and Aging: Weigh out construction waste powder, sludge, and composite sintering aid by weight, mix and stir at 100 r / min for 20 min, and then age for 48 h to obtain aged material.

[0047] S3 Plasticity Adjustment: Weigh out the plasticity adjuster by weight and add it to the aged material. Stir and mix at 300 r / min for 10 min and let it stand for 20 min for plasticity adjustment.

[0048] S4 Forming and Cutting: After plasticity adjustment, the raw material is placed in a plastic soft extrusion blanking machine to extrude clay strips, which are then cut into wet blanks with a moisture content of 25% by a CNC blanking machine to product specifications.

[0049] S5 Drying and Sintering: The wet blanks are dried in a drying oven at 120°C for 8 hours. After drying, they are sintered in a tunnel kiln at 950°C for 5 hours to obtain dry blanks with a moisture content of 4%. The dry blanks are cooled to room temperature at a temperature reduction rate of 10°C / min to obtain environmentally friendly bricks.

[0050] Example 5

[0051] This Example 5 uses the same raw material ratio as Example 3 and is prepared using the following process:

[0052] S1 Raw material preparation: The construction waste is crushed using a crusher to obtain construction waste particles with a diameter of 20mm; the construction waste particles are then ground in a grinder, and the resulting construction waste powder is passed through an 80-mesh sieve.

[0053] S2 Raw Material Mixing and Aging: Weigh out construction waste powder, sludge, and composite sintering aid by weight, mix and stir at 300 r / min for 10 min, and then age for 72 h to obtain aged material.

[0054] S3 Plasticity Adjustment: Weigh out the plasticity adjuster by weight and add it to the aged material. Stir and mix at 500 r / min for 5 min and let it stand for 40 min for plasticity adjustment.

[0055] S4 Forming and Cutting: After plasticity adjustment, the raw material is placed in a plastic soft extrusion blanking machine to extrude clay strips, which are then cut into wet blanks with a moisture content of 15% by a CNC blanking machine to product specifications.

[0056] S5 Drying and Sintering: The wet blanks are dried in a drying oven at 150°C for 6 hours. After drying, they are sintered in a tunnel kiln at 1050°C for 2 hours to obtain dry blanks with a moisture content of 2%. The dry blanks are cooled to room temperature at a temperature reduction rate of 30°C / min to obtain environmentally friendly bricks.

[0057] Comparative Example 1

[0058] The difference between this comparative example and Example 3 is that it includes the following raw materials in parts by weight: 10 parts sludge, 100 parts construction waste, 0.4 parts composite sintering aid composed of silicon nitride, starch, vegetable oil and sodium alginate, and 1.5 parts plasticity modifier.

[0059] Comparative Example 2

[0060] The difference between Comparative Example 2 and Example 3 is that no composite sintering aid is added to the raw materials.

[0061] Comparative Example 3

[0062] The difference between Comparative Example 3 and Example 3 is that the sintering aid is a single silicon nitride.

[0063] Comparative Example 4

[0064] The difference between Comparative Example 4 and Example 3 is that no plasticizer is added to the raw materials.

[0065] Comparative Example 5

[0066] The difference between Comparative Example 5 and Example 3 is that no plasticity adjustment process is included in the preparation process; that is, a plasticity adjuster is added during the raw material mixing and aging process.

[0067] Performance testing

[0068] The flexural strength, compressive strength, and bulk density of the environmentally friendly bricks prepared in Examples 1-5 and Comparative Examples 1-4 were determined according to the methods and requirements of the national standard GB / T 2542-2012 "Test Methods for Masonry Bricks". The test results are shown in Table 1.

[0069] Table 1

[0070]

[0071]

[0072] As can be seen from Table 1, the environmentally friendly bricks prepared by this invention have better performance, especially Example 3, which shows the best results. At the MU15 strength grade, the compressive strength reaches 19.8 MPa, the flexural strength reaches 11.0 MPa, and the bulk density reaches 1386 kg / m³. 3 .

[0073] Comparing Example 3 with Examples 1-2, it can be seen that a specific ratio of raw materials is required to achieve optimal performance. Comparing Example 3 with Examples 4-5, it can be seen that under specific process control, the environmentally friendly bricks produced achieve the best performance.

[0074] A comparison of Example 3 and Comparative Example 1 shows that a specific ratio of raw materials is required to achieve optimal performance. Through the scientific proportioning and synergistic effect of the raw materials at a specific ratio, the functions of the raw materials are fully utilized and mutually complementary, resulting in environmentally friendly bricks with superior performance.

[0075] A comparison of Example 3 and Comparative Example 2 shows that adding the composite sintering aid helps promote complete sintering of the material, thereby improving the performance of the environmentally friendly bricks. This is because silicon nitride in the composite sintering aid promotes heat transfer within the brick body and accelerates moisture evaporation, thus reducing the hindrance of water vapor in the sludge to the sintering reaction. Sodium alginate in the composite sintering aid has good binding and dispersing properties. Adding sodium alginate can improve the binding force of the sludge, making the sludge particles more tightly bonded together, reducing the impact of moisture evaporation on the sintering reaction, and also increasing the brick's bulk density, compressive strength, and flexural strength. During the sintering process, starch in the composite sintering aid can react with carbon in the sludge to form stable compounds, thereby reducing the hindrance of carbon to the sintering reaction. The vegetable oil in the composite sintering aid is rich in unsaturated fatty acids, which can act as a lubricant during the sintering process, making it easier for sludge particles to slide and rearrange, promoting the sintering reaction, ensuring complete sintering of the sludge, and preventing cracks and deformation in the brick during the forming process.

[0076] Comparing Example 3 with Comparative Example 3, it can be seen that the composite sintering aid is more effective than the single silicon nitride sintering aid. Through the specific combination of silicon nitride, sodium alginate, starch, and vegetable oil in the composite sintering aid, the synergistic effect among the components results in better performance of the environmentally friendly bricks.

[0077] Comparing Example 3 and Comparative Example 4, the addition of plasticity modifiers can enhance the plasticity of environmentally friendly bricks, thereby improving their molding performance and strength. When sodium stearate or sodium palmitate is added to the brick-making raw materials, it forms a thin film on the surface of the raw materials, reducing friction and agglomeration between them, making the materials easier to mix evenly. This facilitates better flow and filling of the mold during molding, thereby improving the density and uniformity of the brick blank, and thus enhancing the molding performance, strength, and volume sealing of the brick. Simultaneously, because sodium stearate and sodium palmitate contain long-chain hydrocarbon groups in their molecular structure, these hydrocarbon groups form bridging effects between raw material particles, increasing the adhesion between particles. This increased adhesion allows the raw materials to deform and flow better under external force, thereby improving the plasticity of the brick blank and thus enhancing the molding performance and strength of the brick. The addition of sophora japonica saponins can increase the viscosity of the raw materials, allowing them to better maintain their shape under external force. This increased viscosity helps improve the plasticity of the brick blank, making it easier to deform and fill the mold during molding. At the same time, increased viscosity can reduce shrinkage and cracking of the brick blank during sintering, thereby improving the overall strength of the brick.

[0078] Comparing Example 3 with Comparative Example 5, setting a plasticity adjustment stage in the brick-making process allows for the control of material plasticity as needed. This means that the viscosity and flowability of the material can be adjusted according to the brick forming requirements, improving brick performance and reducing forming defects. By adjusting the plasticity of different materials, more types of construction waste, high-moisture sludge, and other wastes can be included in the raw material range, further improving resource utilization and environmental benefits. A separate plasticity adjustment stage allows for better control of material plasticity. This is because the plasticity adjustment stage allows for precise control of the amount of plasticizer added, thereby achieving precise regulation of material plasticity. In contrast, directly adding plasticizers during the mixing and aging stages may not achieve precise control of material plasticity, as the main purpose of mixing and aging is to stabilize the material, not to regulate plasticity. Furthermore, plasticizers may affect material stability or aging effects. Setting the plasticity adjustment stage separately after the mixing and aging stages avoids the influence of plasticizers on the aging process, ensuring material stability and aging effects.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly brick, characterized in that: The raw materials include the following parts by weight: 2-5 parts sludge, 90-95 parts construction waste, 0.1-0.3 parts composite sintering aid, and 0.5-1.2 parts plasticity modifier; The composite sintering aid is composed of silicon nitride, starch, vegetable oil, and sodium alginate in a mass-volume ratio of (2-6):(1-5):(1-5):(1-3) g / mL. The plastic modifier is one or a combination of sodium palmitate, sodium stearate, and sophora saponins.

2. The environmentally friendly brick as described in claim 1, characterized in that, The sludge is one or a combination of industrial sludge and domestic sludge, and the sludge has a moisture content of 40-80%.

3. The environmentally friendly brick as described in claim 1, characterized in that, The construction waste includes mud, construction slag, mining waste, and tailings.

4. The preparation process of an environmentally friendly brick as described in claim 1, characterized in that: Includes the following steps: S1 Raw material preparation: The construction waste is crushed using a crusher to obtain construction waste particles with a diameter of 10-20mm; Construction waste particles are put into a grinder for grinding, and then the resulting construction waste powder is passed through a 40-80 mesh sieve. S2 Raw Material Mixing and Aging: Weigh out construction waste powder, sludge, and composite sintering aid by weight, mix and stir, and then age to obtain aged material; S3 Plasticity Adjustment: Weigh out the plasticity adjuster by weight and add it to the aged material, stir and mix, and let it stand for plasticity adjustment; S4 Forming and Cutting: After plasticity adjustment, the raw material is placed in a plastic soft extrusion blanking machine to extrude clay strips, which are then cut into wet blanks of product specifications by a CNC blanking machine; S5 Drying and Sintering: The wet blanks are dried in a drying oven, and after drying, they are sintered in a tunnel kiln to obtain dry blanks; the dry blanks are cooled to room temperature to obtain environmentally friendly bricks.

5. The preparation process of an environmentally friendly brick as described in claim 4, characterized in that: The mixing speed in S2 is 100-300 r / min, the mixing time is 10-20 min, and the aging time is 48-72 h.

6. The preparation process of an environmentally friendly brick as described in claim 4, characterized in that: In step S3, the stirring speed is 300-500 r / min, the stirring time is 5-10 min, and the settling time for plasticity adjustment is 20-40 min.

7. The preparation process of an environmentally friendly brick as described in claim 4, characterized in that: The moisture content of the wet blank in S4 is 15-25%.

8. The preparation process of an environmentally friendly brick as described in claim 4, characterized in that: The drying temperature in S5 is 120-150℃, the drying time is 6-8h, the sintering temperature is 950-1050℃, and the sintering time is 2-5h.

9. The preparation process of an environmentally friendly brick as described in claim 4, characterized in that: The moisture content of the dry blank in S5 is 2-4%, and the temperature decrease rate during cooling in S5 is 10-30℃ / min.

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