Water permeable brick based on household garbage incineration slag and preparation method of water permeable brick

Abstract

The invention relates to the technical field of water permeable bricks, in particular to a water permeable brick based on household garbage incineration slag and a preparation method of the water permeable brick. The building material is prepared from the following components in parts by mass: 60 to 70 parts of household garbage incineration slag, 15 to 20 parts of cement, 0.1 to 0.5 part of basalt fiber, 1 to 3 parts of modified charcoal, 2 to 4 parts of sodium bentonite, 1 to 2 parts of an additive, 0.5 to 2 parts of a toughening agent, 0.05 to 0.5 part of a silane coupling agent and 2 to 6 parts of water. According to the water permeable brick based on the household garbage incineration slag and the preparation method of the water permeable brick, the household garbage incineration slag is used in a high proportion, so that solid waste of household garbage incineration is digested, and meanwhile, through the synergistic effect of the modified charcoal, the sodium bentonite and the cement, the water permeable brick is prepared. The problems of environmental protection pain point of slag heavy metal leaching and mechanical property of the water permeable brick are solved.

Description

Technical Field

[0001] This invention relates to the field of permeable brick technology, and in particular to a permeable brick based on municipal solid waste incineration slag and its preparation method. Background Technology

[0002] With the acceleration of urbanization and the in-depth promotion of sponge city construction, permeable bricks, as a new type of building material that combines rainwater infiltration, slip resistance, wear resistance, and environmental protection, are widely used in municipal sidewalks, park landscape areas, and residential roads. Their core requirement is to ensure permeability while possessing sufficient mechanical strength, durability, and environmental friendliness. Meanwhile, municipal solid waste incineration has become the mainstream method for urban solid waste treatment due to its advantages of volume reduction, resource recovery, and harmlessness. However, the resulting emissions of municipal solid waste incineration ash are enormous. If traditional landfill methods are used, it not only occupies a large amount of land resources but may also pollute the soil and groundwater due to the leaching of trace heavy metal ions and soluble harmful substances contained in the ash, causing secondary environmental hazards. Therefore, the resource utilization of municipal solid waste incineration ash has become an urgent environmental and resource issue to be addressed.

[0003] Currently, existing technologies attempt to use municipal solid waste incineration slag as aggregate to prepare permeable bricks, realizing the resource utilization of solid waste and alleviating to some extent the environmental pressure of slag landfill and the shortage of natural aggregate resources. However, existing slag permeable bricks still have many technical pain points in practical applications. After incineration, municipal solid waste incineration slag has a rough surface and many micropores, resulting in high water absorption and weak interfacial adhesion with cement and other cementing materials. When used directly as aggregate, it is prone to problems such as insufficient brick strength, slag shedding, and cracking. Municipal solid waste incineration slag contains trace amounts of heavy metal ions. Current technologies, which only use simple water washing and solidification treatment, cannot achieve efficient fixation of heavy metals. Under long-term rainwater infiltration, heavy metal ions are easily leached out of the permeable bricks, polluting groundwater and soil, and failing to meet the environmental protection requirements of green building materials. Summary of the Invention

[0004] The purpose of this invention is to provide a permeable brick based on municipal solid waste incineration slag and its preparation method. By using a high proportion of municipal solid waste incineration slag, the solid waste from municipal solid waste incineration can be disposed of. At the same time, through the synergistic effect of modified biochar, sodium bentonite, and cement, the environmental pain point of heavy metal leaching from the slag and the mechanical performance problem of permeable bricks can be solved.

[0005] To achieve the above objectives, the present invention provides a permeable brick based on municipal solid waste incinerator slag, wherein the components, by mass parts, include 60-70 parts of municipal solid waste incinerator slag, 15-20 parts of cement, 0.1-0.5 parts of basalt fiber, 1-3 parts of modified biochar, 2-4 parts of sodium bentonite, 1-2 parts of additives, 0.5-2 parts of toughening agent, 0.05-0.5 parts of silane coupling agent, and 2-6 parts of water.

[0006] Preferably, the municipal solid waste incineration slag includes fine particles of municipal solid waste incineration slag with a particle size of 0.1-2 mm and coarse particles of municipal solid waste incineration slag with a particle size of 3-15 mm, and the mass ratio of fine particles to coarse particles of municipal solid waste incineration slag is 3-4:6-7.

[0007] Preferably, the modified biochar is biochar loaded with nano-metals, including one or more of nano-manganese, nano-iron, nano-magnesium, and nano-aluminum.

[0008] Preferably, the additives include one or more of the following: air-entraining agents, water-reducing agents, early-strength agents, antibacterial agents, waterproofing agents, and retarders.

[0009] Preferably, the air-entraining agent includes one or more of rosin thermal polymers, saponins, and sodium dodecyl sulfate.

[0010] Preferably, the antibacterial agent includes one or more of nano zinc oxide, nano titanium dioxide, silver-loaded zeolite, and chitosan.

[0011] Preferably, the waterproofing agent includes one or more of calcium stearate, acrylic emulsion, and fluorosilane.

[0012] Preferably, the toughening agent includes one or more of polyurethane emulsions, epoxy resin emulsions, and polycarboxylate-based toughening additives.

[0013] The above-mentioned method for preparing permeable bricks based on municipal solid waste incinerator slag includes the following steps: S1. After magnetic separation, screening and washing of municipal solid waste incineration slag, a curing agent is added and cured at room temperature. After drying, the slag is ball-milled to obtain coarse particles and fine particles of municipal solid waste incineration slag for later use. S2. After carbonizing the straw, crush and sieve it, then immerse it in a metal salt solution. After immersion, centrifuge to separate the solid, dry it, and then calcine it to obtain modified biochar for later use. S3. First, premix the coarse particles of municipal solid waste incinerator slag, fine particles of municipal solid waste incinerator slag, and silane coupling agent obtained in S1. Then, add cement and sodium-based bentonite and mix. Next, add basalt fiber, modified biochar obtained in S2, and toughening agent and continue mixing. Finally, add additives and water and mix evenly to obtain a mixture. S4. Place the mixture obtained in S3 into a mold and press it into shape to obtain a permeable brick blank; S5. The permeable brick blanks obtained in S4 are sent to the curing room and cured at room temperature for 7 days with moisture retention, followed by natural curing for 21-28 days. After curing, permeable bricks are obtained.

[0014] Preferably, in S1, the curing agent is a cement-based curing agent, and the amount of curing agent used is 2-3% of the mass of municipal solid waste incinerator slag.

[0015] Preferably, in S2, the carbonization temperature is 500-700℃, the carbonization time is 2-3h, the solid-liquid ratio of straw and metal salt solution is 1:10-20, and the roasting is carried out under an inert atmosphere at a temperature of 300-400℃.

[0016] Preferably, in step S3, the stirring rate is 500-1000 r / min and the stirring time is 3-8 min.

[0017] Preferably, in step S4, the pressing pressure is 15-30 MPa and the time is 10-60 s.

[0018] Therefore, the present invention employs the above-mentioned permeable brick based on municipal solid waste incineration slag and its preparation method, the beneficial effects of which are: 1. The permeable brick provided by this invention has coarse particles of municipal solid waste incineration slag forming the main permeable channel, and fine particles of municipal solid waste incineration slag filling the gaps between the coarse particles to form a pore skeleton with good connectivity and stable structure. Sodium-based bentonite fills the micro gaps between the components, which not only does not block the main permeable channel, but also improves the density and prevents the pores from collapsing. At the same time, its porous structure can form secondary permeable channels to further improve permeability. 2. In the permeable brick provided by the present invention, cement and water undergo a hydration reaction to generate CSH gel, which binds the components such as municipal solid waste incinerator slag, modified biochar, and sodium bentonite into a whole, giving the brick a foundation of compressive and flexural strength. The alkaline environment of cement can promote the secondary hydration reaction of slag, generate more CSH gel, and further improve the bonding strength. 3. The modified biochar in the permeable brick provided by this invention adsorbs trace heavy metals in slag through the reaction of nano-metals with heavy metal ions; the alkaline environment of cement can form hydroxide precipitates to further fix heavy metal ions; the ion exchange capacity of sodium-based bentonite can adsorb heavy metal ions, and the three form a triple fixation effect, which greatly reduces the risk of heavy metal leaching, meets environmental protection requirements, and realizes the resource utilization of slag solid waste.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1This is a statistical chart of the permeability coefficient of the permeable bricks in Examples 1-5 and Comparative Examples 1-2 of the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0022] This invention provides a permeable brick based on municipal solid waste incinerator slag. The components, by weight, include 60-70 parts municipal solid waste incinerator slag, 15-20 parts cement, 0.1-0.5 parts basalt fiber, 1-3 parts modified biochar, 2-4 parts sodium bentonite, 1-2 parts additives, 0.5-2 parts toughening agent, 0.05-0.5 parts silane coupling agent, and 2-6 parts water. The municipal solid waste incinerator slag provides the framework for the permeable channels. Cement binds the loose municipal solid waste incinerator slag and other components into a whole, giving the brick basic mechanical strength. The basalt fiber forms a three-dimensional randomized network structure inside the brick, dispersing external stress and inhibiting crack formation. The modified biochar, utilizing its ultra-large specific surface area and nano-metal loading characteristics, adsorbs and fixes trace heavy metals in the slag, reducing the risk of leaching. Sodium-based bentonite, with its high adsorption and ion exchange capacity, enhances rainwater purification while filling micro-gaps between components. This prevents blockage of the main permeable channels and increases the density of the framework. The flexible groups of the toughening agent improve the toughness of the cementitious matrix and strengthen the interfacial bond between basalt fibers and the matrix, preventing fiber debonding. Silane coupling agents form chemical bridges on the surfaces of each component through hydrolysis, improving the interfacial adhesion between municipal solid waste incinerator slag, fibers, and cementitious materials, thus addressing the problems of high water absorption and poor interfacial compatibility in municipal solid waste incinerator slag.

[0023] In some embodiments of the present invention, the municipal solid waste incineration slag includes fine particles of municipal solid waste incineration slag with a particle size of 0.1-2 mm and coarse particles of municipal solid waste incineration slag with a particle size of 3-15 mm, wherein the mass ratio of fine particles to coarse particles is 3-4:6-7. The coarse particles of municipal solid waste incineration slag serve as the main framework, forming interconnected large pore channels to ensure high permeability. The fine particles of municipal solid waste incineration slag fill some of the voids between the coarse particles, ensuring both high permeability and improving the density and mechanical stability of the municipal solid waste incineration slag aggregate framework, avoiding the problems of insufficient strength due to excessively large pores or poor permeability due to excessively small pores caused by slag of a single particle size.

[0024] In some embodiments of the present invention, the modified biochar is biochar loaded with nano-metals, including one or more of nano-manganese, nano-iron, nano-magnesium, and nano-aluminum. Nano-metals are highly active and can chemically react with heavy metal ions in the slag. Combined with the physical adsorption of biochar, this significantly reduces the risk of heavy metal leaching.

[0025] In some embodiments of the present invention, the additives include one or more of the following: air-entraining agents, water-reducing agents, early-strength agents, antibacterial agents, waterproofing agents, and retarders. Different types of additives are selected according to the application scenario of the permeable bricks. Air-entraining agents are suitable for freeze-thaw cycles in northern regions; water-reducing agents balance strength and permeability; early-strength agents improve production efficiency; antibacterial agents are suitable for public places; waterproofing agents improve durability; and retarders are suitable for high-temperature construction. The additives can be compounded according to actual needs to enhance the versatility and adaptability of the formula.

[0026] In some embodiments of the present invention, the air-entraining agent includes one or more of rosin thermal polymers, saponins, and sodium dodecyl sulfate.

[0027] In some embodiments of the present invention, the antibacterial agent includes one or more of nano zinc oxide, nano titanium dioxide, silver-loaded zeolite, and chitosan.

[0028] In some embodiments of the present invention, the waterproofing agent includes one or more of calcium stearate, acrylic emulsion, and fluorosilane.

[0029] In some embodiments of the present invention, the toughening agent includes one or more of polyurethane emulsions, epoxy resin emulsions, and polycarboxylate-based toughening additives. The toughening agent possesses both hydrophilicity and adhesive properties, making it compatible with inorganic components such as cement and municipal solid waste incineration slag, and synergistic with basalt fibers and silane coupling agents to enhance interfacial adhesion. Simultaneously, it improves the brittleness of cement, preventing cracking of the brick under load, thus meeting the long-term service requirements of permeable bricks.

[0030] The above-mentioned method for preparing permeable bricks based on municipal solid waste incinerator slag includes the following steps: S1. After sequentially performing magnetic separation, screening, and water washing on municipal solid waste incineration slag, a curing agent is added for room temperature curing and drying. After drying, the slag is ball-milled to obtain coarse and fine particles of municipal solid waste incineration slag for later use. This process removes impurities from the municipal solid waste incineration slag, optimizes the particle size distribution, and fixes heavy metals. The process involves removing metals through magnetic separation, determining the particle size distribution through screening, removing soluble impurities through water washing, fixing heavy metals through curing, and ball milling to improve interfacial adhesion, laying the foundation for subsequent component synergy.

[0031] S2. After carbonizing the straw, crush and sieve it, then immerse it in a metal salt solution for impregnation. After impregnation, centrifuge to obtain solid, dry and calcine to obtain modified biochar for later use. Through carbonization, impregnation and calcination processes, the pore structure of biochar is activated to achieve nano-metal loading, ensuring its adsorption performance and chemical activity, and ensuring the environmental synergistic effect with municipal solid waste incineration slag.

[0032] S3. First, premix the coarse particles and fine particles of municipal solid waste incinerator slag obtained in S1 with the silane coupling agent. Then, add cement and sodium-based bentonite and mix. Next, add basalt fiber, modified biochar obtained in S2, and toughening agent and continue mixing. Finally, add additives and water and mix evenly to obtain a mixture. After hydrolysis, the silane coupling agent forms a hydrophobic interface layer on the surface of the municipal solid waste incinerator slag particles, reducing the water absorption rate of the municipal solid waste incinerator slag and preventing excessive water absorption by the municipal solid waste incinerator slag, which would lead to insufficient cement hydration. At the same time, its functional groups combine with the hydroxyl groups on the surface of the municipal solid waste incinerator slag, improving the interfacial adhesion between the municipal solid waste incinerator slag and the cement gel and reducing interface defects.

[0033] S4. Place the mixture obtained in S3 into a mold and press it to form a permeable brick blank. Through the action of pressure, the aggregate particles are tightly interlocked to form a stable pore structure, while ensuring the density of the brick body and balancing permeability and mechanical strength.

[0034] S5. The permeable brick blanks obtained in S4 are sent to a curing room and cured with moisture for 7 days at room temperature, followed by natural curing for 21-28 days. After curing, permeable bricks are obtained. The first 7 days of moisture curing promotes cement hydration and secondary hydration of municipal solid waste incineration slag, ensuring the early strength of the bricks. The subsequent natural curing improves the durability of the bricks, allows the synergistic effect of each component to be fully exerted, and avoids cracking and insufficient strength caused by improper curing.

[0035] In some embodiments of the present invention, in S1, the curing agent is a cement-based curing agent, and the amount of curing agent used is 2-3% of the mass of municipal solid waste incineration slag. Without affecting the porosity of the municipal solid waste incineration slag, it further fixes heavy metals and simultaneously helps to improve the adhesion between the municipal solid waste incineration slag and cement, forming an environmentally friendly synergy with modified biochar.

[0036] In some embodiments of the present invention, in S2, the carbonization temperature is 500-700℃, the carbonization time is 2-3h to activate the pore structure of biochar, the solid-liquid ratio of straw and metal salt solution is 1:10-20, and calcination is carried out under an inert atmosphere at a temperature of 300-400℃. Calcination under an inert atmosphere can avoid oxidation of nano-metals and ensure their activity.

[0037] In some embodiments of the present invention, in step S3, the stirring rate is 500-1000 r / min and the stirring time is 3-8 min. This avoids component agglomeration (especially basalt fiber and modified biochar) and ensures uniform mixing of all components, while allowing the silane coupling agent to be fully hydrolyzed and the toughening agent to be fully dispersed, thus ensuring the synergistic effect of the components.

[0038] In some embodiments of the present invention, in step S4, the pressing pressure is 15-30 MPa, and the time is 10-60 seconds. This can be fine-tuned according to the brick thickness and application scenario to ensure the brick's density and porosity stability. The holding time avoids porosity damage caused by a sudden increase in pressure, while allowing the aggregate particles to be fully embedded, balancing permeability and strength.

[0039] Example 1 S1. After sequentially performing magnetic separation, screening, and water washing on the municipal solid waste incineration slag, a cement-based curing agent is added for room temperature curing. The amount of curing agent used is 2% of the mass of the municipal solid waste incineration slag. After drying, ball milling yields 18 parts of fine particles and 42 parts of coarse particles of municipal solid waste incineration slag for later use.

[0040] S2. After carbonizing the straw, crush and sieve it. The carbonization temperature is 600℃ and the carbonization time is 2.5h. Then, immerse it in a metal salt solution with a solid-liquid ratio of 1:10. After immersion, centrifuge to obtain solid, dry it, and then calcine it under an inert atmosphere at a temperature of 350℃ to obtain modified biochar (loaded with nano-manganese metal) for later use.

[0041] S3. First, premix the coarse particles (3-15mm) and fine particles (0.1-2mm) of municipal solid waste incinerator slag obtained in S1 with 0.05 parts of silane coupling agent. The mixing speed is 800 r / min and the mixing time is 3 min. Then, add 15 parts of cement and 2 parts of sodium bentonite and mix. Next, add 0.1 parts of basalt fiber, 1 part of modified biochar obtained in S2, and 0.5 parts of toughening agent (polyurethane emulsion) and continue mixing. Finally, add 1 part of additives (70% water-reducing agent, 10% early-strength agent, 10% antibacterial agent, and 10% waterproof agent) and 2 parts of water and mix evenly to obtain the mixture.

[0042] S4. Place the mixture obtained in S3 into a mold and press it into shape. The pressure is 15MPa and the time is 20s to obtain a permeable brick blank.

[0043] S5. The permeable brick blank obtained in S4 is sent to the curing room and cured at room temperature for 7 days with moisture retention, followed by natural curing for 28 days. After curing, permeable bricks are obtained.

[0044] Example 2 S1. After sequentially performing magnetic separation, screening, and water washing on the municipal solid waste incineration slag, a cement-based curing agent is added for room temperature curing. The amount of curing agent used is 3% of the mass of the municipal solid waste incineration slag. After drying, the slag is ball-milled to obtain 28 parts of fine particles and 42 parts of coarse particles of municipal solid waste incineration slag for later use.

[0045] S2. After carbonizing the straw, crush and sieve it. The carbonization temperature is 600℃ and the carbonization time is 3h. Then, immerse it in a metal salt solution with a solid-liquid ratio of 1:20 between the straw and the metal salt solution. After immersion, centrifuge to obtain solid. After drying, calcine it under an inert atmosphere at a temperature of 400℃ to obtain modified biochar (supported with nano-magnesium metal) for later use.

[0046] S3. First, premix the coarse particles (3-15mm) and fine particles (0.1-2mm) of municipal solid waste incinerator slag obtained in S1 with 0.5 parts of silane coupling agent. The mixing speed is 800 r / min and the mixing time is 5 min. Then, add 20 parts of cement and 4 parts of sodium-based bentonite and mix. Next, add 0.5 parts of basalt fiber, 3 parts of modified biochar obtained in S2, and 2 parts of toughening agent (epoxy resin emulsion) and continue mixing. Finally, add 2 parts of additives (70% water-reducing agent, 10% early-strength agent, 5% antibacterial agent, and 15% air-entraining agent) and 6 parts of water and mix evenly to obtain the mixture.

[0047] S4. Place the mixture obtained in S3 into a mold and press it into shape. The pressure is 30MPa and the time is 20s to obtain a permeable brick blank.

[0048] S5. The permeable brick blank obtained in S4 is sent to the curing room and cured at room temperature for 7 days with moisture retention, followed by natural curing for 28 days. After curing, permeable bricks are obtained.

[0049] Example 3 S1. After sequentially performing magnetic separation, screening, and water washing on the municipal solid waste incineration slag, a cement-based curing agent is added for room temperature curing. The amount of curing agent used is 2.5% of the mass of the municipal solid waste incineration slag. After drying, ball milling yields 22.75 parts of fine particles and 42.25 parts of coarse particles of municipal solid waste incineration slag for later use.

[0050] S2. After carbonizing the straw, crush and sieve it. The carbonization temperature is 600℃ and the carbonization time is 2.5h. Then, immerse it in a metal salt solution with a solid-liquid ratio of 1:15. After immersion, centrifuge to separate the solid. After drying, calcine it under an inert atmosphere at a temperature of 400℃ to obtain modified biochar (with a mass ratio of 1:1 of nano-metallic iron and nano-metallic manganese) for later use.

[0051] S3. First, premix the coarse particles (3-15mm) and fine particles (0.1-2mm) of municipal solid waste incinerator slag obtained in S1 with 0.2 parts of silane coupling agent. The mixing speed is 800 r / min and the mixing time is 5 min. Then, add 18 parts of cement and 3 parts of sodium bentonite and mix. Next, add 0.5 parts of basalt fiber, 2 parts of modified biochar obtained in S2, and 1 part of toughening agent (epoxy resin emulsion and polycarboxylate-based toughening additive in a 1:1 mass ratio) and continue mixing. Finally, add 1.5 parts of additives (70% water-reducing agent, 5% early-strength agent, 10% antibacterial agent, and 15% waterproofing agent) and 5 parts of water and mix evenly to obtain the mixture.

[0052] S4. Place the mixture obtained in S3 into a mold and press it into shape. The pressure is 20MPa and the time is 20s to obtain a permeable brick blank.

[0053] S5. The permeable brick blank obtained in S4 is sent to the curing room and cured at room temperature for 7 days with moisture retention, followed by natural curing for 28 days. After curing, permeable bricks are obtained.

[0054] Example 4 S1. After sequentially performing magnetic separation, screening, and water washing on the municipal solid waste incineration slag, a cement-based curing agent is added for room temperature curing. The amount of curing agent used is 2% of the mass of the municipal solid waste incineration slag. After drying, ball milling yields 18.6 parts of fine particles and 43.4 parts of coarse particles of municipal solid waste incineration slag for later use.

[0055] S2. After carbonizing the straw, crush and sieve it. The carbonization temperature is 600℃ and the carbonization time is 2.5h. Then, immerse it in a metal salt solution with a solid-liquid ratio of 1:10. After immersion, centrifuge to separate the solid. After drying, calcine it under an inert atmosphere at a temperature of 400℃ to obtain modified biochar (with a mass ratio of 1:1 of nano-magnesium and nano-aluminum) for later use.

[0056] S3. First, premix the coarse particles (3-15mm) and fine particles (0.1-2mm) of municipal solid waste incinerator slag obtained in S1 with 0.3 parts of silane coupling agent. The mixing speed is 800 r / min and the mixing time is 6 min. Then, add 20 parts of cement and 4 parts of sodium-based bentonite and mix. Next, add 0.5 parts of basalt fiber, 3 parts of modified biochar obtained in S2, and 1 part of toughening agent (polyurethane emulsion and epoxy resin emulsion in a 1:1 mass ratio) and continue mixing. Finally, add 1.5 parts of additives (70% water-reducing agent, 10% early-strength agent, 10% antibacterial agent, and 10% waterproof agent) and 5 parts of water and mix evenly to obtain the mixture.

[0057] S4. Place the mixture obtained in S3 into a mold and press it into shape. The pressure is 20MPa and the time is 20s to obtain a permeable brick blank.

[0058] S5. The permeable brick blank obtained in S4 is sent to the curing room and cured at room temperature for 7 days with moisture retention, followed by natural curing for 28 days. After curing, permeable bricks are obtained.

[0059] Example 5 S1. After sequentially performing magnetic separation, screening, and water washing on the municipal solid waste incineration slag, a cement-based curing agent is added for room temperature curing. The amount of curing agent used is 2.5% of the mass of the municipal solid waste incineration slag. After drying, the slag is ball-milled to obtain 21 parts of fine particles and 49 parts of coarse particles of municipal solid waste incineration slag for later use.

[0060] S2. After carbonizing the straw, crush and sieve it. The carbonization temperature is 600℃ and the carbonization time is 2.5h. Then, immerse it in a metal salt solution with a solid-liquid ratio of 1:18. After immersion, centrifuge to obtain solid. After drying, calcine it under an inert atmosphere at a temperature of 400℃ to obtain modified biochar (loaded with nano-manganese metal) for later use.

[0061] S3. First, premix the coarse particles (3-15mm) and fine particles (0.1-2mm) of municipal solid waste incinerator slag obtained in S1 with 0.2 parts of silane coupling agent. The mixing speed is 800 r / min and the mixing time is 5 min. Then, add 18 parts of cement and 3 parts of sodium bentonite and mix. Next, add 0.35 parts of basalt fiber, 2 parts of modified biochar obtained in S2, and 1 part of toughening agent (polycarboxylate-based toughening additive) and continue mixing. Finally, add 1 part of additive (70% water-reducing agent, 10% early-strength agent, 10% antibacterial agent, and 10% waterproofing agent) and 4 parts of water and mix evenly to obtain the mixture.

[0062] S4. Place the mixture obtained in S3 into a mold and press it into shape. The pressure is 20MPa and the time is 20s to obtain a permeable brick blank.

[0063] S5. The permeable brick blank obtained in S4 is sent to the curing room and cured at room temperature for 7 days with moisture retention, followed by natural curing for 28 days. After curing, permeable bricks are obtained.

[0064] Comparative Example 1 The difference between this comparative example and Example 3 is that step S2 was not performed, and modified biochar and sodium bentonite were not added. All other steps were the same as in Example 3, resulting in permeable bricks.

[0065] Comparative Example 2 The difference between this comparative example and Example 4 is that basalt fiber, sodium bentonite, and toughening agent were not added. All other steps were the same as in Example 4 to obtain permeable bricks.

[0066] Performance testing According to GB / T 25993-2010 "Permeable Pavement Bricks and Permeable Pavement Panels", the permeable bricks in Examples 1-5 and Comparative Examples 1-2 were tested, and the results are shown in Table 1.

[0067] Table 1 Mechanical data of permeable bricks in Examples 1-5 and Comparative Examples 1-2

[0068] According to HJ / T 300-2007 "Solid Waste Leaching Toxicity Leaching Method Acetic Acid Buffer Solution Method" (simulated acid rain conditions), the permeable bricks in Examples 1-5 and Comparative Examples 1-2 were tested, and the results are shown in Table 2.

[0069] Table 2. Metal leaching from permeable bricks in Examples 1-5 and Comparative Examples 1-2

[0070] According to Appendix A (Constant Water Level Method) of GB / T 25993-2010, the permeable bricks in Examples 1-5 and Comparative Examples 1-2 were tested, and the results are as follows: Figure 1 As shown in Table 1-2 and Figure 1 It can be seen that the permeable bricks in Examples 1-5 exhibit superior mechanical properties, metal leaching, and permeability compared to the permeable bricks in Comparative Examples 1-2.

[0071] Therefore, the present invention adopts the above-mentioned permeable brick based on municipal solid waste incineration slag and its preparation method. By using a high proportion of municipal solid waste incineration slag, the solid waste disposal of municipal solid waste incineration is realized. At the same time, through the synergistic effect of modified biochar, sodium bentonite and cement, the environmental pain point of heavy metal leaching from slag and the mechanical performance problem of permeable bricks are solved.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A permeable brick based on municipal solid waste incineration slag, characterized in that: The components, by mass, include 60-70 parts of municipal solid waste incinerator slag, 15-20 parts of cement, 0.1-0.5 parts of basalt fiber, 1-3 parts of modified biochar, 2-4 parts of sodium bentonite, 1-2 parts of additives, 0.5-2 parts of toughening agent, 0.05-0.5 parts of silane coupling agent, and 2-6 parts of water.

2. The permeable brick based on municipal solid waste incinerator slag according to claim 1, characterized in that: Municipal solid waste incineration slag includes fine particles of municipal solid waste incineration slag with a particle size of 0.1-2mm and coarse particles of municipal solid waste incineration slag with a particle size of 3-15mm. The mass ratio of fine particles to coarse particles of municipal solid waste incineration slag is 3-4:6-7.

3. The permeable brick based on municipal solid waste incinerator slag according to claim 1, characterized in that: The modified biochar is biochar loaded with nano-metals, including one or more of nano-manganese, nano-iron, nano-magnesium, and nano-aluminum.

4. A permeable brick based on municipal solid waste incinerator slag according to claim 1, characterized in that: Additives include one or more of the following: air-entraining agents, water-reducing agents, early-strength agents, antibacterial agents, waterproofing agents, and retarders.

5. A permeable brick based on municipal solid waste incinerator slag according to claim 1, characterized in that: Toughening agents include one or more of polyurethane emulsions, epoxy resin emulsions, and polycarboxylate-based toughening additives.

6. A method for preparing permeable bricks based on municipal solid waste incinerator slag, characterized in that: The preparation of permeable bricks based on municipal solid waste incinerator slag as described in any one of claims 1-5 comprises the following steps: S1. After magnetic separation, screening and washing of municipal solid waste incineration slag, a curing agent is added and cured at room temperature. After drying, the slag is ball-milled to obtain coarse particles and fine particles of municipal solid waste incineration slag for later use. S2. After carbonizing the straw, crush and sieve it, then immerse it in a metal salt solution. After immersion, centrifuge to separate the solid, dry it, and then calcine it to obtain modified biochar for later use. S3. First, premix the coarse particles of municipal solid waste incinerator slag, fine particles of municipal solid waste incinerator slag, and silane coupling agent obtained in S1. Then, add cement and sodium-based bentonite and mix. Next, add basalt fiber, modified biochar obtained in S2, and toughening agent and continue mixing. Finally, add additives and water and mix evenly to obtain a mixture. S4. Place the mixture obtained in S3 into a mold and press it into shape to obtain a permeable brick blank; S5. The permeable brick blanks obtained in S4 are sent to the curing room and cured at room temperature for 7 days with moisture retention, followed by natural curing for 21-28 days. After curing, permeable bricks are obtained.

7. The method for preparing permeable bricks based on municipal solid waste incinerator slag according to claim 6, characterized in that: In S1, the curing agent is a cement-based curing agent, and the amount of curing agent used is 2-3% of the mass of municipal solid waste incineration slag.

8. The method for preparing permeable bricks based on municipal solid waste incinerator slag according to claim 6, characterized in that: In S2, the carbonization temperature is 500-700℃, the carbonization time is 2-3h, the solid-liquid ratio of straw and metal salt solution is 1:10-20, and it is roasted in an inert atmosphere at a temperature of 300-400℃.

9. A method for preparing permeable bricks based on municipal solid waste incinerator slag according to claim 6, characterized in that: In S3, the stirring rate is 500-1000 r / min and the stirring time is 3-8 min.

10. A method for preparing permeable bricks based on municipal solid waste incinerator slag according to claim 6, characterized in that: In S4, the pressing pressure is 15-30MPa and the time is 10-60s.

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