Preparation method of environment-friendly shale brick based on multi-source waste

Abstract

The invention discloses a preparation method of an environment-friendly shale brick based on multi-source waste, and relates to the technical field of building material preparation, the preparation method comprises the following steps: S1, raw material preparation: 80-100 parts of modified sludge powder, 120-150 parts of shale powder, 60-80 parts of industrial waste soil powder, 80-90 parts of furnace ash, 10-15 parts of cement, 3-5 parts of lime, 3-5 parts of plant fiber and 20-30 parts of functional auxiliary materials; s2, mixing the raw materials to form mixed slurry; s3, injecting the mixture into a mold, performing pressure forming to obtain a green brick, and drying the green brick; and S4, sintering, and naturally cooling to obtain a shale brick finished product. According to the method, the physical properties and functional characteristics of the shale brick are remarkably improved, in the preparation process of the modified sludge powder, through the steps of chemical modification, biological modification and the like, the properties of the sludge are effectively improved, the sludge is more suitable for being used as a building material, and meanwhile, the shale brick is endowed with the characteristics of heat preservation, heat insulation and the like due to the addition of functional auxiliary materials.

Description

Technical Field

[0001] The invention relates to the technical field of building material preparation, and in particular to a method for preparing environmentally friendly shale bricks based on multi-source waste. Background Art

[0002] With the acceleration of urbanization and the continuous development of industrial production, a large amount of waste such as sludge, industrial waste soil powder, ash slag, etc. is constantly generated, which brings great pressure to the environment. If these wastes are not properly utilized and treated, they will not only occupy a large amount of land resources, but also pollute the soil, water and air, seriously affecting the ecological balance and human health. Therefore, how to efficiently and environmentally friendly treat these wastes and realize the reuse of resources has become a problem that needs to be solved urgently.

[0003] Traditional waste disposal methods, such as landfill and incineration, not only have high disposal costs, but may also cause secondary pollution. In recent years, with the enhancement of environmental awareness and the advancement of technology, people have begun to explore methods of using waste to prepare building materials in order to realize the resource utilization of waste. Among them, shale bricks, as a common building material, have attracted much attention due to their good physical properties and environmental characteristics.

[0004] However, the traditional shale brick preparation mainly relies on natural shale resources, which not only consumes a lot of natural resources, but also has a high production cost. Therefore, using waste as the raw material of shale bricks can not only reduce production costs, but also realize the resource utilization of waste and reduce environmental pollution. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an environmentally friendly shale brick preparation method based on multi-source waste, which has a wide range of raw material sources, a simple preparation process and stable product performance, as follows:

[0006] A method for preparing environmentally friendly shale bricks based on multi-source waste, such as Figure 1 As shown, the following steps are included:

[0007] S1. Raw material preparation: by mass: 80-100 parts of modified sludge powder, 120-150 parts of shale powder, 60-80 parts of industrial waste soil powder, 80-90 parts of ash, 10-15 parts of cement, 3-5 parts of lime, 3-5 parts of plant fiber, and 20-30 parts of functional auxiliary materials;

[0008] S2, raw material mixing: after mixing the raw materials, add pure water and stir to form a mixed slurry;

[0009] S3, forming and drying: injecting the mixed slurry into a mold, forming the bricks by pressure, and placing them in a drying chamber for drying;

[0010] S4, sintering: the dried bricks are sent to the sintering furnace for sintering. After sintering, they are naturally cooled to obtain the finished shale bricks.

[0011] The particle size of the modified sludge powder is less than 0.2 mm;

[0012] The particle size of the shale powder, industrial waste soil powder and furnace ash is less than 2 mm;

[0013] The particle size of the cement and lime is less than 0.2 mm.

[0014] Furthermore, the preparation method of the modified sludge powder is as follows: Figure 2 As shown:

[0015] Step 1, dehydration treatment: dehydrating the sludge to obtain a sludge cake, crushing and screening the sludge cake to obtain sludge particles with uniform particle size; the particle size of the sludge particles is less than 2 mm; the particle size of the sludge particles is less than 2 mm;

[0016] Step 2, chemical modification: adding a chemical modifier and pure water to the sludge particles, stirring and mixing at 70°C-80°C for 25-35 minutes, so that the chemical modifier and the sludge fully react to form a sludge modified product; the amount of pure water added is 50%-60% of the sludge particles by mass;

[0017] Step 3, biological modification: adding sucrose and rice straw to the sludge modification, mixing, and fermenting in a closed manner at a constant temperature for 8-10 days to obtain fermented sludge, drying the fermented sludge at 105-110° C. to constant weight to obtain modified sludge; grinding and sieving the modified sludge to obtain modified sludge powder.

[0018] Furthermore, in step 1, the moisture content of the sludge cake is 30%-40%;

[0019] In step 2, the amount of the chemical modifier added is 20%-25% of the sludge particles by mass;

[0020] The chemical modifier comprises lime, fly ash and polyaluminium chloride, and the mass ratio is lime: fly ash: polyaluminium chloride = 10:20:1.

[0021] Furthermore, in the step 3, the added amount of the sucrose is 3%-5% of the modified sludge, and the added amount of the rice straw is 4%-6% of the modified sludge, by mass.

[0022] Furthermore, the functional auxiliary materials include 70-80 parts of pyrolysis material, 5-10 parts of petroleum resin, 5-8 parts of terpene resin, and 1-1.5 parts of nano iron powder, calculated by weight.

[0023] Further, the particle size of the pyrolysis material is less than 0.5 mm;

[0024] The particle size of the petroleum resin is less than 200 microns;

[0025] The particle size of the terpene resin is less than 200 microns;

[0026] The particle size of the nano iron powder is 50-100 nanometers.

[0027] Furthermore, the preparation method of the pyrolysis material is as follows: heating the lignite to 550°C-650°C under the protection of an inert gas and pyrolyzing it for 10-12 hours, continuing to heat it to 950°C-1000°C and pyrolyzing it for 20-24 hours, and naturally cooling it to room temperature to obtain the pyrolysis material.

[0028] Furthermore, the inert gas is nitrogen or argon.

[0029] Furthermore, the petroleum resin is C5 petroleum resin.

[0030] Furthermore, the preparation method of the functional auxiliary material is as follows: after mixing the pyrolysis material, petroleum resin, terpene resin and nano iron powder, heating and stirring the mixture under the protection of inert gas for 45-60 minutes, and then keeping the mixture at 140℃-150℃ for 5-8 hours to obtain a functional auxiliary material with thermal insulation function.

[0031] Furthermore, in step 1, the sludge is activated sludge from the secondary sedimentation tank of a domestic sewage treatment plant or river sludge.

[0032] Furthermore, in step S2, the added mass of pure water is 10%-15% of the mixed slurry; in step S3, during pressure molding, the pressure is 30-50MPa, the humidity in the drying chamber is 70-80°C, and the humidity is 30%-60%RH; in step S4, the humidity of sintering is 900°C-1200°C.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention rationally utilizes multi-source waste such as sludge, industrial waste soil powder, furnace ash slag, etc., and uses them as the main raw materials for shale bricks, thereby achieving efficient utilization and reduction of waste, which not only reduces the accumulation and landfill of waste, reduces environmental pollution, but also saves natural resources.

[0035] 2. By adding modified sludge powder, lime, cement and other raw materials, as well as specific functional auxiliary materials, the preparation method of the present invention significantly improves the strength and thermal insulation performance of shale bricks. During the preparation of modified sludge powder, the properties of the sludge are effectively improved through chemical modification, biological modification and other steps, making it more suitable for use as a building material. At the same time, the addition of functional auxiliary materials gives shale bricks thermal insulation and heat insulation properties, thereby improving their use value and market competitiveness.

[0036] 3. The present invention adds a chemical modifier (lime: fly ash: polyaluminium chloride = 10:20:1) to the sludge to chemically modify the sludge:

[0037] (1) Through chemical modification, the particle structure of sludge is optimized, and interstitial water and capillary bound water are easier to remove. Specifically, chemical modifiers can destroy the colloidal stability in sludge, making it easier to remove water through mechanical dehydration methods, which not only reduces the volume of sludge, but also provides favorable conditions for subsequent biological modification and drying processes;

[0038] (2) Polyaluminium chloride also has flocculation and precipitation effects, which can remove harmful substances such as heavy metal ions and organic pollutants in sludge, and help improve the environmental performance and subsequent utilization value of sludge;

[0039] (3) Chemically modified sludge can form a microporous structure, which helps to improve its thermal insulation performance in shale bricks;

[0040] (4) Chemical modification can change the physicochemical properties of sludge, such as pH value, conductivity, and viscosity, making it more suitable for use as a building material;

[0041] (5) Chemical modification can increase the active sites on the surface of sludge particles, so that they can be better combined with other raw materials, such as shale powder and cement, during the mixing and sintering process to form a denser brick structure;

[0042] (6) Chemical modification can neutralize the acidic substances in the sludge, reduce the dissolution of heavy metal ions, and reduce the potential harm of sludge to the environment.

[0043] 4. The present invention chemically modifies the sludge and then adds sucrose and rice straw to biologically modify the sludge:

[0044] (1) By adding sucrose and rice straw to the sludge modification product for constant temperature and closed fermentation, the microorganisms and other organic matter in the sludge can be further decomposed and transformed, which helps to further remove harmful substances in the sludge and stabilize the properties of the sludge;

[0045] (2) During the biological modification process, the decomposition of sucrose and straw will generate a certain amount of heat and moisture, which is easier to remove in the subsequent drying process. At the same time, the fermentation can also change the particle structure and gap distribution of the sludge, making it easier to dehydrate, which helps to improve the drying efficiency of the modified sludge and reduce energy consumption;

[0046] (3) During the biological modification process, microorganisms will use the organic matter in the sludge as a carbon source and energy source for growth and reproduction, thereby further decomposing the organic matter and reducing the organic matter content in the sludge; the microbial metabolites produced during the biological modification process can give the bricks certain antibacterial and anti-mildew properties, thereby increasing the service life of the bricks;

[0047] (4) After biological modification, the microbial community structure in the sludge changes, which helps to improve the biological stability of the sludge and eliminate the odor and harmful gas emissions during the storage and use of the sludge;

[0048] (5) During the biological modification process, the aggregation and growth of microorganisms can promote the formation and stabilization of sludge particles, which helps to obtain a more uniform particle size distribution in the subsequent preparation of modified sludge powder;

[0049] (6) The fermentation process of sucrose and rice straw enables the degradation of macromolecular organic matter in the sludge. At the same time, the difficult-to-degrade components in the rice straw play a reinforcing and toughening effect in the sludge system, further improving the mechanical properties of sludge shale bricks.

[0050] 5. The modified sludge powder prepared by the present invention has a more uniform particle size distribution after chemical modification and biological modification, which is conducive to better mixing and reaction with other raw materials during the preparation of shale bricks. After the sludge is modified, its physical properties such as moisture content and plasticity index are optimized, making it more suitable for use as a building material.

[0051] 6. The present invention adds functional auxiliary materials to the raw materials, including 70-80 parts of pyrolysis material, 5-10 parts of petroleum resin, 5-8 parts of terpene resin, and 1-1.5 parts of nano iron powder:

[0052] (1) Improve brick strength and durability:

[0053] The carbonaceous components and inorganic substances in the pyrolysis material can form a denser brick structure with other raw materials such as shale powder and lime; petroleum resin and terpene resin, as tackifiers and plasticizers, can improve the bonding strength of the components in the brick body, thereby enhancing the overall strength of the brick body; the addition of nano iron powder can fill the tiny pores in the brick body, improving the density and durability;

[0054] (2) Improve the thermal performance of bricks:

[0055] The carbonaceous component in the pyrolysis material has good thermal conductivity, which can improve the thermal conductivity of shale bricks; nano iron powder can also enhance the thermal conductivity of the brick body and play a role in electromagnetic shielding; the addition of petroleum resin and terpene resin can improve the thermal insulation performance of the brick body, making it have better thermal insulation effect.

[0056] 6. The present invention adds plant fiber to the raw materials, which can increase the toughness and crack resistance of the brick body and reduce the cracks and damage that may occur in the brick body during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A flow chart of the shale brick preparation method provided by the present invention;

[0058] Figure 2 The present invention provides a flow chart of the method for preparing modified sludge powder. DETAILED DESCRIPTION

[0059] Example 1

[0060] A method for preparing environmentally friendly shale bricks based on multi-source wastes comprises the following steps:

[0061] S1. Raw material preparation: by mass: 80 parts of modified sludge powder, 120 parts of shale powder, 60 parts of industrial waste soil powder, 80 parts of ash, 10 parts of cement, 3 parts of lime, 3 parts of plant fiber, and 20 parts of functional auxiliary materials;

[0062] S2, raw material mixing: after mixing the raw materials, add pure water and stir to form a mixed slurry;

[0063] S3, forming and drying: injecting the mixed slurry into a mold, forming the bricks by pressure, and placing them in a drying chamber for drying;

[0064] S4, sintering: the dried bricks are sent to the sintering furnace for sintering. After sintering, they are naturally cooled to obtain the finished shale bricks.

[0065] Preferably, the particle size of the modified sludge powder is less than 0.2 mm;

[0066] The particle size of the shale powder, industrial waste soil powder and furnace ash is less than 2 mm;

[0067] The particle size of the cement and lime is less than 0.2 mm.

[0068] Preferably, the preparation method of the modified sludge powder is as follows:

[0069] Step 1, dehydration treatment: dehydrating the sludge to obtain a sludge cake, crushing and screening the sludge cake to obtain sludge particles; the particle size of the sludge particles is less than 2 mm;

[0070] Step 2, chemical modification: adding a chemical modifier and pure water to the sludge particles, stirring and mixing at 70° C. for 25 minutes, so that the chemical modifier and the sludge fully react to form a sludge modified product; the amount of pure water added is 50% of the sludge particles by mass;

[0071] Step 3, biological modification: adding sucrose and rice straw to the modified sludge, mixing, and fermenting in a closed manner at a constant temperature for 8 days to obtain fermented sludge, and drying the fermented sludge at 105° C. to a constant weight to obtain modified sludge;

[0072] The modified sludge is ground and sieved to obtain modified sludge powder.

[0073] Preferably, in step 1, the moisture content of the sludge cake is 30%;

[0074] In step 2, the chemical modifier includes lime, fly ash and polyaluminium chloride, and the mass ratio of lime: fly ash: polyaluminium chloride is 10:20:1;

[0075] The added amount of the chemical modifier is 20% of the sludge particles by mass.

[0076] Preferably, in step 3, the added amount of sucrose is 3% of the modified sludge, and the added amount of rice straw is 4% of the modified sludge, by mass.

[0077] Preferably, the functional auxiliary materials include 70 parts of pyrolysis material, 5 parts of petroleum resin, 5-8 parts of terpene resin, and 1-1.5 parts of nano iron powder, calculated by weight.

[0078] Preferably, the preparation method of the pyrolysis material is as follows: heating the lignite to 550°C under the protection of an inert gas and pyrolyzing it for 10 hours, then heating it to 950°C and pyrolyzing it for 20 hours, and naturally cooling it to room temperature to obtain the pyrolysis material.

[0079] Preferably, the petroleum resin 5 parts is C5 petroleum resin, terpene resin 5 parts, and nano iron powder 1 part.

[0080] Preferably, the preparation method of the functional auxiliary material is as follows: after mixing the pyrolysis material, petroleum resin, terpene resin and nano iron powder, heating and stirring the mixture under the protection of inert gas for 45 minutes, and then keeping the mixture at 140°C-150°C for 5 hours to obtain a functional auxiliary material with thermal insulation function.

[0081] Preferably, the particle size of the pyrolysis material is less than 0.5 mm;

[0082] The particle size of the petroleum resin is less than 200 microns;

[0083] The particle size of the terpene resin is less than 200 microns;

[0084] The particle size of the nano iron powder is less than 100 nanometers.

[0085] Preferably, in step 1, the sludge is activated sludge from the secondary sedimentation tank of a domestic sewage treatment plant.

[0086] Preferably, in step S2, the added mass of pure water is 10% of the mixed slurry; in step S3, during pressure molding, the pressure is 30MPa, the humidity in the drying chamber is 70°C, and the humidity is 30%RH; in step S4, the humidity of sintering is 900°C.

[0087] Example 2

[0088] A method for preparing environmentally friendly shale bricks based on multi-source waste includes the following steps:

[0089] S1. Raw material preparation: by mass: 100 parts of modified sludge powder, 150 parts of shale powder, 80 parts of industrial waste soil powder, 90 parts of ash, 15 parts of cement, 5 parts of lime, 5 parts of plant fiber, and 30 parts of functional auxiliary materials;

[0090] S2, raw material mixing: after mixing the raw materials, add pure water and stir to form a mixed slurry;

[0091] S3, forming and drying: injecting the mixed slurry into a mold, forming the bricks by pressure, and placing them in a drying chamber for drying;

[0092] S4, sintering: the dried bricks are sent to the sintering furnace for sintering. After sintering, they are naturally cooled to obtain the finished shale bricks.

[0093] Preferably, the particle size of the modified sludge powder is less than 0.2 mm;

[0094] The particle size of the shale powder, industrial waste soil powder and furnace ash is less than 2 mm;

[0095] The particle size of the cement and lime is less than 0.2 mm.

[0096] Preferably, the preparation method of the modified sludge powder is as follows:

[0097] Step 1, dehydration treatment: dehydrating the sludge to obtain a sludge cake, crushing and screening the sludge cake to obtain sludge particles; the particle size of the sludge particles is less than 2 mm;

[0098] Step 2, chemical modification: adding a chemical modifier and pure water to the sludge particles, stirring and mixing at 80° C. for 35 minutes, so that the chemical modifier and the sludge fully react to form a sludge modified product; the amount of pure water added is 60% of the sludge particles by mass;

[0099] Step 3, biological modification: adding sucrose and rice straw to the sludge modification, mixing, and fermenting in a closed manner at a constant temperature for 10 days to obtain fermented sludge; drying the fermented sludge at 110° C. to constant weight to obtain modified sludge; grinding and sieving the modified sludge to obtain modified sludge powder.

[0100] Preferably, in step 1, the moisture content of the sludge cake is 40%;

[0101] In step 2, the chemical modifier includes lime, fly ash and polyaluminium chloride, and the mass ratio of lime: fly ash: polyaluminium chloride is 10:20:1;

[0102] Preferably, the particle size of the pyrolysis material is less than 0.5 mm;

[0103] The particle size of the petroleum resin is less than 200 microns;

[0104] The particle size of the terpene resin is less than 200 microns;

[0105] The particle size of the nano iron powder is less than 100 nanometers.

[0106] The added amount of the chemical modifier is 25% of the sludge particles by mass.

[0107] Preferably, in step 3, the added amount of sucrose is 5% of the modified sludge, and the added amount of rice straw is 6% of the modified sludge, by mass.

[0108] Preferably, the functional auxiliary materials include 80 parts of pyrolysis material, 10 parts of petroleum resin, 8 parts of terpene resin, and 1.5 parts of nano iron powder, calculated by mass.

[0109] Preferably, the preparation method of the pyrolysis material is as follows: heating the lignite to 650°C under the protection of an inert gas and pyrolyzing it for 12 hours, then heating it to 1000°C and pyrolyzing it for 24 hours, and naturally cooling it to room temperature to obtain the pyrolysis material.

[0110] Preferably, the petroleum resin is C5 petroleum resin.

[0111] Preferably, the preparation method of the functional auxiliary material is as follows: after mixing the pyrolysis material, petroleum resin, terpene resin and nano iron powder, heating and stirring the mixture under inert gas protection for 60 minutes, and then keeping the mixture at 150° C. for 8 hours to obtain a functional auxiliary material with thermal insulation function.

[0112] Preferably, in step 1, the sludge is river sludge.

[0113] Preferably, in step S2, the added mass of pure water is 15% of the mixed slurry; in step S3, during pressure molding, the pressure is 50MPa, the humidity in the drying chamber is 80°C, and the humidity is 60%RH; in step S4, the humidity of sintering is 1200°C.

[0114] Example 3

[0115] A method for preparing environmentally friendly shale bricks based on multi-source wastes comprises the following steps:

[0116] S1. Raw material preparation: by mass: 90 parts of modified sludge powder, 130 parts of shale powder, 70 parts of industrial waste soil powder, 85 parts of ash, 13 parts of cement, 4 parts of lime, 4 parts of plant fiber, and 25 parts of functional auxiliary materials;

[0117] S2, raw material mixing: after mixing the raw materials, add pure water and stir to form a mixed slurry;

[0118] S3, forming and drying: injecting the mixed slurry into a mold, forming the bricks by pressure, and placing them in a drying chamber for drying;

[0119] S4, sintering: the dried bricks are sent to the sintering furnace for sintering. After sintering, they are naturally cooled to obtain the finished shale bricks.

[0120] Preferably, the particle size of the modified sludge powder is less than 0.2 mm;

[0121] The particle size of the shale powder, industrial waste soil powder and furnace ash is less than 2 mm;

[0122] The particle size of the cement and lime is less than 0.2 mm.

[0123] Preferably, the preparation method of the modified sludge powder is as follows:

[0124] Step 1, dehydration treatment: dehydrating the sludge to obtain a sludge cake, crushing and screening the sludge cake to obtain sludge particles; the particle size of the sludge particles is less than 2 mm;

[0125] Step 2, chemical modification: adding a chemical modifier and pure water to the sludge particles, stirring and mixing at 75° C. for 30 minutes, so that the chemical modifier and the sludge fully react to form a sludge modified product; the amount of pure water added is 55% of the sludge particles by mass;

[0126] Step 3, biological modification: adding sucrose and rice straw to the sludge modification, mixing, and fermenting in a closed manner at a constant temperature for 9 days to obtain fermented sludge; drying the fermented sludge at 108° C. to constant weight to obtain modified sludge; grinding and sieving the modified sludge to obtain modified sludge powder.

[0127] Preferably, in step 1, the moisture content of the sludge cake is 35%;

[0128] In step 2, the chemical modifier includes lime, fly ash and polyaluminium chloride, and the mass ratio of lime: fly ash: polyaluminium chloride is 10:20:1;

[0129] The added amount of the chemical modifier is 23% of the sludge particles by mass.

[0130] Preferably, in step 3, the added amount of sucrose is 4% of the modified sludge, and the added amount of rice straw is 5% of the modified sludge, by mass.

[0131] Preferably, the functional auxiliary materials include 75 parts of pyrolysis material, 8 parts of petroleum resin, 7 parts of terpene resin and 1.2 parts of nano iron powder, calculated by weight.

[0132] Preferably, the preparation method of the pyrolysis material is as follows: heating the lignite to 600°C under the protection of an inert gas and pyrolyzing it for 11 hours, then heating it to 980°C and pyrolyzing it for 22 hours, and naturally cooling it to room temperature to obtain the pyrolysis material.

[0133] Preferably, the petroleum resin is C5 petroleum resin.

[0134] Preferably, the preparation method of the functional auxiliary material is as follows: after mixing the pyrolysis material, petroleum resin, terpene resin and nano iron powder, heating and stirring the mixture under inert gas protection for 53 minutes, and then keeping the mixture at 145° C. for 6 hours to obtain a functional auxiliary material with thermal insulation function.

[0135] Preferably, the particle size of the pyrolysis material is less than 0.5 mm;

[0136] The particle size of the petroleum resin is less than 200 microns;

[0137] The particle size of the terpene resin is less than 200 microns;

[0138] The particle size of the nano iron powder is less than 100 nanometers.

[0139] Preferably, in step 1, the sludge is activated sludge from the secondary sedimentation tank of a domestic sewage treatment plant.

[0140] Preferably, in step S2, the added mass of pure water is 12% of the mixed slurry; in step S3, during pressure molding, the pressure is 40MPa, the humidity in the drying chamber is 75°C, and the humidity is 45%RH; in step S4, the humidity of sintering is 1000°C.

[0141] Example 4

[0142] A method for preparing modified sludge powder is as follows:

[0143] Step 1, dehydration treatment: dehydrating the activated sludge in the secondary sedimentation tank of the domestic sewage treatment plant to obtain a sludge cake, crushing and screening the sludge cake to obtain sludge particles; the particle size of the sludge particles is less than 2 mm;

[0144] Step 2, chemical modification: adding a chemical modifier and pure water to the sludge particles, stirring and mixing at 75° C. for 30 minutes, so that the chemical modifier and the sludge fully react to form a sludge modified product; the amount of pure water added is 55% of the sludge particles by mass;

[0145] Step 3, biological modification: adding sucrose and rice straw to the modified sludge, mixing, and fermenting in a closed manner at a constant temperature for 9 days to obtain fermented sludge, and drying the fermented sludge at 108° C. to a constant weight to obtain modified sludge;

[0146] The modified sludge is ground and sieved to obtain modified sludge powder.

[0147] Preferably, in step 1, the moisture content of the sludge cake is 35%;

[0148] In step 2, the chemical modifier includes lime, fly ash and polyaluminium chloride, and the mass ratio of lime: fly ash: polyaluminium chloride is 10:20:1;

[0149] The added amount of the chemical modifier is 23% of the sludge particles by mass.

[0150] Preferably, in step 3, the added amount of sucrose is 4% of the modified sludge, and the added amount of rice straw is 5% of the modified sludge, by mass.

[0151] Example 5

[0152] A method for preparing modified sludge powder is as follows:

[0153] Step 1, dehydration treatment: dehydrating the sludge to obtain a sludge cake, crushing and screening the sludge cake to obtain sludge particles; the particle size of the sludge particles is less than 2 mm;

[0154] Step 2, chemical modification: adding a chemical modifier and pure water to the sludge particles, stirring and mixing at 70° C. for 25 minutes, so that the chemical modifier and the sludge fully react to form a sludge modified product; the amount of pure water added is 50% of the sludge particles by mass;

[0155] Step 3, biological modification: adding sucrose and rice straw to the modified sludge, mixing, and fermenting in a closed manner at a constant temperature for 8 days to obtain fermented sludge, and drying the fermented sludge at 105° C. to a constant weight to obtain modified sludge;

[0156] The modified sludge is ground and sieved to obtain modified sludge powder.

[0157] Preferably, in step 1, the moisture content of the sludge cake is 30%;

[0158] In step 2, the chemical modifier includes lime, fly ash and polyaluminium chloride, and the mass ratio of lime: fly ash: polyaluminium chloride is 10:20:1;

[0159] The added amount of the chemical modifier is 20% of the sludge particles by mass.

[0160] Preferably, in step 3, the added amount of sucrose is 3% of the modified sludge, and the added amount of rice straw is 4% of the modified sludge, by mass.

[0161] Example 6

[0162] A method for preparing modified sludge powder is as follows:

[0163] Step 1, dehydration treatment: dehydrating the sludge to obtain a sludge cake, crushing and screening the sludge cake to obtain sludge particles; the particle size of the sludge particles is less than 2 mm;

[0164] Step 2, chemical modification: adding a chemical modifier and pure water to the sludge particles, stirring and mixing at 80° C. for 35 minutes, so that the chemical modifier and the sludge fully react to form a sludge modified product; the amount of pure water added is 60% of the sludge particles by mass;

[0165] Step 3, biological modification: adding sucrose and rice straw to the modified sludge, mixing, and fermenting in a closed manner at a constant temperature for 10 days to obtain fermented sludge, and drying the fermented sludge at 110° C. to a constant weight to obtain modified sludge;

[0166] The modified sludge is ground and sieved to obtain modified sludge powder.

[0167] Preferably, in step 1, the moisture content of the sludge cake is 40%;

[0168] In step 2, the chemical modifier includes lime, fly ash and polyaluminium chloride, and the mass ratio of lime: fly ash: polyaluminium chloride is 10:20:1;

[0169] The added amount of the chemical modifier is 25% of the sludge particles by mass.

[0170] Preferably, in step 3, the added amount of sucrose is 5% of the modified sludge, and the added amount of rice straw is 6% of the modified sludge, by mass.

[0171] Comparative Example 1

[0172] The difference between this comparative example and Example 3 is that no functional auxiliary material is added.

[0173] Comparative Example 2

[0174] The difference between this comparative example and Example 3 is that when the modified sludge powder is prepared, step 2 is not performed, that is, no chemical modification is performed.

[0175] Comparative Example 3

[0176] The difference between this comparative example and Example 3 is that when the modified sludge powder is prepared, step 4 is not performed, that is, no biological modification is performed.

[0177] Comparative Example 4

[0178] In the step 2, no polyaluminium chloride is added to the chemical modifier.

[0179] Experimental Section

[0180] Experiment 1

[0181] Take five shale bricks (240mm×115mm×53mm) prepared in Examples 1-3 and Comparative Examples 1-4, and after normal curing, use a pressure testing machine to perform a compression test, record the compressive strength value of each sample, and calculate the average value. The results are shown in Table 1.

[0182] Table 1 Average compressive strength

[0183] Serial number Compressive strength(MPa) Example 1 34.2 Example 2 35.3 Example 3 35.6 Comparative Example 1 29.9 Comparative Example 2 24.3 Comparative Example 3 33.7 Comparative Example 4 31.5

[0184] It can be seen from Table 1 that the compressive strength of Examples 1 to 3 is the highest, reaching 35.6 MPa, and the compressive strength of Comparative Examples 1 to 4 is lower than that of the Examples.

[0185] In Comparative Example 1, the compressive strength of the brick body decreased due to the lack of functional auxiliary materials, indicating that functional auxiliary materials play an important role in enhancing the compressive strength of shale bricks. This may be because the carbonaceous components and inorganic substances in the pyrolysis materials can form a denser brick structure with other raw materials such as shale powder and lime; petroleum resin and terpene resin, as tackifiers and plasticizers, can improve the bonding strength of the components in the brick body, thereby enhancing the overall strength of the brick body; the addition of nano iron powder can fill the tiny pores in the brick body, improving the density and durability.

[0186] The compressive strength of Example 2 was significantly reduced due to the lack of chemical modification, indicating that chemical modification is crucial to the modification and improvement of the binding force of sludge particles. This may be because chemical modification can increase the active sites on the surface of sludge particles, allowing them to better combine with other raw materials, such as shale powder, cement, etc., during the mixing and sintering process to form a denser brick structure, thereby improving the compressive strength of shale bricks.

[0187] The compressive strength of Comparative Example 3 also decreased due to the lack of biological modification, but the decrease was relatively small. This was caused by the more uniform particle size distribution of the modified sludge powder during the biological modification process. It may also be because a small amount of rice straw was added, which had a reinforcing and toughening effect.

[0188] The compressive strength of Comparative Example 4 decreased because no polyaluminium chloride was added to the chemical modifier, but the decrease was smaller than that of Comparative Example 2. This may be because no polyaluminium chloride was added to Comparative Example 4, which may lead to a weakened chemical modification effect and a decrease in the quality and performance of the sludge modified product, which in turn may affect the strength and stability of the final shale bricks. This shows that polyaluminium chloride plays an important role in chemical modification and may help to improve the strength and stability of sludge powder.

[0189] Experiment 2

[0190] After normal curing, the shale bricks (240 mm × 115 mm × 53 mm) prepared in Examples 1-3 and Comparative Examples 1-4 were placed on the test bench of a thermal resistance tester to ensure that the sample was in close contact with the test probe. The tester was started and a 50 W / m 2 The heat flow is measured by the temperature sensor at the same time. The temperature difference on both sides of the sample is measured. The temperature difference, heat flow value, sample thickness and other parameters during the test are recorded. The thermal resistance of the shale brick is calculated as R=ΔT / Q, where R is the thermal resistance, ΔT is the temperature difference, and Q is the heat flow value. The results are shown in Table 2.

[0191] Table 2 Shale brick thermal resistance test results

[0192] Serial number <![CDATA[Thermal resistance R (m 2 ·K / W)]]> Temperature difference ΔT(℃) <![CDATA[Heat flux value Q (W / m 2 )]]> Sample thickness (mm) Example 1 0.45 22.3 50 53 Example 2 0.46 23.2 50 53 Example 3 0.45 22.5 50 53 Comparative Example 1 0.38 19.0 50 53 Comparative Example 2 0.40 20.0 50 53 Comparative Example 3 0.44 22.0 50 53 Comparative Example 4 0.43 21.5 50 53

[0193] It can be seen from Table 2 that the thermal resistance R values ​​of Example 1, Example 2 and Example 3 are all higher than those of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4, which indicates that the environmentally friendly shale brick preparation method based on multi-source waste of the present invention can significantly improve the thermal resistance performance of shale bricks and enhance the thermal insulation performance.

[0194] Comparative Example 1 does not add functional auxiliary materials, and its thermal resistance R value is only 0.38m 2 K / W, much lower than 0.45m in Example 3 2 ·K / W, which shows that the functional auxiliary materials can effectively improve the thermal insulation performance of shale bricks. This may be because the carbonaceous component of the pyrolysis material has good thermal conductivity, which can improve the thermal conductivity of shale bricks; nano iron powder can also enhance the thermal conductivity of the brick body and play an electromagnetic shielding role; the addition of petroleum resin and terpene resin can improve the thermal insulation performance of the brick body, making it have a better thermal insulation effect.

[0195] Comparative Example 2 did not undergo chemical modification when preparing the modified sludge powder, and its thermal resistance R value was 0.40 m 2 K / W, lower than 0.45m in Example 3 2 ·K / W, which may be because the chemically modified sludge can form a microporous structure, which helps to improve its thermal insulation performance in shale bricks.

[0196] The effect of Example 3 on the brick body is relatively weak. The main purpose of biological modification is to remove harmful substances in the sludge, decompose organic matter in the sludge, and improve the antibacterial and mildew resistance of the brick body. It has no significant effect on improving its thermal insulation effect.

[0197] Since no polyaluminium chloride was added to the chemical modifier in Comparative Example 4, the effect was worse than that of Examples 1-3 and the effect was not significant.

Claims

1. A method for preparing environmentally friendly shale bricks based on multi-source waste, characterized in that: The steps include: S1. Raw material preparation: by mass: 80-100 parts of modified sludge powder, 120-150 parts of shale powder, 60-80 parts of industrial waste soil powder, 80-90 parts of ash, 10-15 parts of cement, 3-5 parts of lime, 3-5 parts of plant fiber, and 20-30 parts of functional auxiliary materials; S2, raw material mixing: after mixing the raw materials, add pure water and stir to form a mixed slurry; S3, forming and drying: injecting the mixed slurry into a mold, forming the bricks by pressure, and placing them in a drying chamber for drying; S4, sintering: the dried bricks are sent to the sintering furnace for sintering. After sintering, they are naturally cooled to obtain the finished shale bricks.

2. The method for preparing environmentally friendly shale bricks based on multi-source waste according to claim 1, characterized in that: The preparation method of the modified sludge powder is as follows: Step 1, dehydration treatment: dehydrating the sludge to obtain a sludge cake, crushing and screening the sludge cake to obtain sludge particles; the particle size of the sludge particles is less than 2 mm; Step 2, chemical modification: adding chemical modifier and pure water to the sludge particles, stirring and mixing at 70°C-80°C for 25-35 minutes, so that the chemical modifier and the sludge fully react to form a sludge modified product; Step 3, biological modification: adding sucrose and rice straw to the modified sludge, mixing, and fermenting in a closed manner at a constant temperature for 8-10 days to obtain fermented sludge, and drying the fermented sludge at 105-110° C. to a constant weight to obtain modified sludge; The modified sludge is ground and sieved to obtain modified sludge powder.

3. The method for preparing environmentally friendly shale bricks based on multi-source waste according to claim 2, characterized in that: In step 1, the moisture content of the sludge cake is 30%-40%; In step 2, the chemical modifier includes lime, fly ash and polyaluminium chloride, and the mass ratio is lime: fly ash: polyaluminium chloride = 10:20:1; the added amount of the chemical modifier is 20%-25% of the sludge particles; the added amount of the pure water is 50%-60% of the sludge particles.

4. The method for preparing environmentally friendly shale bricks based on multi-source waste according to claim 3, characterized in that: In the step 3, the added amount of the sucrose is 3%-5% of the modified sludge, and the added amount of the rice straw is 4%-6% of the modified sludge.

5. The method for preparing environmentally friendly shale bricks based on multi-source waste according to claim 1, characterized in that: In parts by mass, the functional auxiliary materials include 70-80 parts of pyrolysis material, 5-10 parts of petroleum resin, 5-8 parts of terpene resin, and 1-1.5 parts of nano iron powder; The particle size of the pyrolysis material is less than 0.5 mm; The particle size of the petroleum resin is less than 200 microns; The particle size of the terpene resin is less than 200 microns; The particle size of the nano iron powder is less than 100 nanometers.

6. The method for preparing environmentally friendly shale bricks based on multi-source waste according to claim 3, characterized in that: The preparation method of the pyrolysis material is as follows: heating the lignite to 550°C-650°C under the protection of inert gas and pyrolyzing it for 10-12 hours, then heating it to 950°C-1000°C and pyrolyzing it for 20-24 hours, and naturally cooling it to room temperature to obtain the pyrolysis material.

7. The method for preparing environmentally friendly shale bricks based on multi-source waste according to claim 1, characterized in that: The particle size of the modified sludge powder is less than 0.2 mm; The particle size of the shale powder, industrial waste soil powder and furnace ash is less than 2 mm; The particle size of the cement and lime is less than 0.2 mm.

8. The method for preparing environmentally friendly shale bricks based on multi-source waste according to claim 5, characterized in that: The preparation method of the functional auxiliary material is as follows: after mixing the pyrolysis material, petroleum resin, terpene resin and nano iron powder, heating and stirring the mixture under the protection of inert gas for 45-60 minutes, and then keeping the mixture at 140° C.-150° C. for 5-8 hours to obtain the functional auxiliary material with heat preservation function.

9. The method for preparing environmentally friendly shale bricks based on multi-source waste according to claim 2, characterized in that: In the step 1, the sludge is activated sludge from the secondary sedimentation tank of a domestic sewage treatment plant or river sludge.

10. The method for preparing environmentally friendly shale bricks based on multi-source waste according to claim 1, characterized in that: In the step S2, the added mass of pure water is 10%-15% of the mixed slurry; in the step S3, during pressure molding, the pressure is 30-50MPa, the humidity in the drying chamber is 70-80°C, and the humidity is 30%-60%RH; in the step S4, the humidity of sintering is 900°C-1200°C.

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