Method for preparing high-performance baking-free brick from sludge of water supply plant

Abstract

The invention relates to the technical field of water supply plant sludge treatment, in particular to a method for preparing a high-performance baking-free brick by using water supply plant sludge, which comprises the following steps of: mixing the water supply plant sludge and magnesium oxychloride cement according to a certain proportion, adding a key modifier A and a key modifier B according to a certain proportion, and uniformly mixing; the method is simple to operate and easy to implement on a large scale, the mechanical property of the obtained high-performance baking-free brick is greatly improved compared with the mechanical property of the high-performance baking-free brick which is independently added into magnesium oxychloride cement by water supply plant sludge, the high-performance baking-free brick can be used for solving the problem of water supply plant sludge recovery, and meanwhile, the sludge treatment cost is greatly reduced; according to the method, the sludge of the water supply plant is efficiently treated, the defect that after the magnesium oxychloride cement is added into the sludge of the water supply plant, the mechanical property is greatly reduced is overcome, the improved baking-free brick can be used in the field of buildings, the practical application and commercial popularization of sludge recycling of the water supply plant are effectively promoted, and the dual-carbon strategic target is promoted to be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of water plant sludge treatment, and in particular to a method for preparing high-performance unburned bricks by utilizing water plant sludge. Background Art

[0002] Water plant sludge contains a certain amount of inorganic components, such as Al2O3, Fe2O3, SiO2, etc., which have potential resource utilization value. However, due to the high water content and low strength of the sludge, it is often not directly used as building materials. In recent years, the use of water plant sludge to prepare building materials has gradually become a feasible resource utilization approach.

[0003] However, with the rapid development of society, urban industrial water and urban residential water consumption are increasing year by year, the water output of water plants is increasing, and the sludge production is also greatly increased. The demand for sludge disposal in water plants is increasing accordingly. The cost of sludge disposal in water plants is expensive and if the disposal method is inappropriate, it will also cause pollution to the social environment. Therefore, there is still an urgent need for sludge treatment technology in water plants. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing high-performance unburned bricks using sludge from a water supply plant, so as to solve the problem in the prior art that with the rapid development of society, urban industrial water and urban residential water use are increasing year by year, the water output of water supply plants is increasing, and the sludge production is also greatly increased. The demand for sludge disposal in water supply plants is increasing accordingly, while the cost of sludge disposal in water supply plants is expensive and if the disposal method is inappropriate, it will also cause pollution to the social environment. Therefore, there is still an urgent need for sludge treatment technology in water supply plants.

[0005] To achieve the above object, the present invention provides a method for preparing high-performance unburned bricks using water supply plant sludge, and the method for preparing high-performance unburned bricks using water supply plant sludge comprises the following steps: S1: Mixing magnesium oxide, magnesium chloride and water in proportion, and adding key modifier A to obtain a modified magnesium oxychloride cement precursor; S2: Testing the mechanical properties of magnesium oxychloride cement precursor; S3: The obtained magnesium oxychloride cement precursor is mixed with the sludge from the water supply plant, and the key modifier B is added to the mixture, and then placed in an environment of specific temperature and specific humidity for maintenance for a specific time, so as to obtain unfired bricks with high mechanical properties.

[0006] Wherein, in step S1, the magnesium chloride is magnesium oxide powder, the magnesium oxide is magnesium chloride hexahydrate, and the molar ratio of the magnesium oxide, magnesium chloride and water is 6-12:1:12-15.

[0007] Among them, in step S1, the key modifier A is coal ash powder and polypropylene fiber. The grade of the coal ash powder is greater than 120 mesh, the content of the coal ash powder is 10%-30%, the diameter of the polypropylene fiber is 33μm, the length is 12mm, and the content of the polypropylene fiber is 0.25%-1%.

[0008] Among them, in step S2, the key modifier B is a water reducer and an acidic modifier. The water reducer is polycarboxylic acid, the acidic modifier is glycolic acid, the content of the water reducer is 0.5%-2%, and the content of the glycolic acid is 0.5%-2.5%.

[0009] Among them, in step S2, the mixing ratio range of the magnesium oxychloride cement precursor and the water treatment plant sludge is 2.3:4.0.

[0010] Among them, in step S2, the specific temperature is 20°C - 45°C, and the specific humidity is 70%-75%.

[0011] Among them, in step S2, the specific time is 7 days to 14 days.

[0012] A method for preparing high-performance non-fired bricks using water treatment plant sludge according to the present invention mixes the water treatment plant sludge and magnesium oxychloride cement in a certain proportion, and adds key modifier A and key modifier B in a certain proportion, and high-performance non-fired bricks can be obtained. This method is simple to operate and easy to implement on a large scale. The mechanical properties of the obtained high-performance non-fired bricks show a significant improvement compared to when the water treatment plant sludge is added alone to magnesium oxychloride cement. It can be used to solve the problem of recycling water treatment plant sludge, greatly reduce the sludge disposal cost, achieve efficient treatment of water treatment plant sludge, and improve the defect that the mechanical properties are greatly reduced after adding water treatment plant sludge to magnesium oxychloride cement. The improved non-fired bricks can be used in the construction field, effectively promoting the practical application and commercial promotion of the resource utilization of water treatment plant sludge, and promoting the realization of the dual-carbon strategic goal. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0014] Figure 1 It is a flowchart of the steps of the method for preparing high-performance non-fired bricks using water treatment plant sludge provided by the present invention.

[0015] Figure 2It is a comparison chart of the flexural and compressive strengths of the non-fired brick Z1 made by mixing the waterworks sludge of the comparative example with magnesium oxychloride cement and the non-fired brick Z2 made by mixing the waterworks sludge of the example and multiple modifiers with magnesium oxychloride cement. Detailed implementation manners

[0016] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0017] Please refer to Figures 1 - 2 , the present invention provides a method for preparing high-performance non-fired bricks using waterworks sludge. The method for preparing high-performance non-fired bricks using waterworks sludge includes the following steps: S1: Mix magnesium oxide, magnesium chloride and water in proportion, and add the key modifier A to obtain a modified magnesium oxychloride cement precursor; S2: Test the mechanical properties of the magnesium oxychloride cement precursor; S3: Mix the obtained magnesium oxychloride cement precursor with waterworks sludge, and add the key modifier B for mixing, and then place it in an environment with a specific temperature and a specific humidity for maintenance for a specific time to obtain a high-mechanical-property non-fired brick.

[0018] In this embodiment, compared with the current sintered materials, the non-fired materials of this design do not require high-temperature calcination, significantly reducing energy consumption and waste gas emissions. Not only does it reduce production costs, but it also has better environmental benefits. Using waterworks sludge to prepare non-fired bricks as a green, environmentally friendly and low-cost resource treatment method has become a research hotspot in the construction field. These non-fired bricks not only have broad application prospects, but also can bring direct economic benefits to the construction industry. At the same time, making full use of the resource value of waterworks sludge and the advantages of non-fired bricks, preparing non-fired bricks in the form of using waterworks sludge as an auxiliary material or a raw material substitute, adding key modifiers during the preparation process to improve or regulate the performance of non-fired bricks, and finally applying them to different scenarios according to the mechanical property differences of the prepared non-fired bricks to achieve efficient treatment of waterworks sludge, effectively promoting the practical application and commercial promotion of the resource utilization of waterworks sludge, and promoting the realization of the dual-carbon strategic goal.

[0019] Among them, in step S1, the magnesium chloride is magnesium oxide powder, the magnesium oxide is magnesium chloride hexahydrate, and the molar ratio of the mixture of magnesium oxide, magnesium chloride and water is 6-12:1:12-15. By precisely controlling the mixing ratio of magnesium oxide, magnesium chloride and water, the performance of the magnesium oxychloride cement precursor can be optimized. This proportional relationship helps to form a stable chemical structure, thereby improving the mechanical properties of the non-fired bricks.

[0020] Among them, in step S1, the key modifier A is coal ash powder and polypropylene fiber. The grade of the coal ash powder is greater than 120 mesh, the content of the coal ash powder is 10%-30%, the diameter of the polypropylene fiber is 33μm, the length is 12mm, and the content of the polypropylene fiber is 0.25%-1%. By adding coal ash powder and polypropylene fiber as the key modifier A, the mechanical properties of the non-fired bricks can be significantly improved. The coal ash powder provides additional strength and durability, while the polypropylene fiber enhances the crack resistance and toughness of the material. At the same time, by precisely controlling the grade and dosage of the modifier, the performance of the non-fired bricks can be further optimized.

[0021] Among them, in step S2, the key modifier B is a water reducing agent and an acidic modifier. The water reducing agent is polycarboxylic acid, the acidic modifier is glycolic acid, the content of the water reducing agent is 0.5%-2%, and the content of the glycolic acid is 0.5%-2.5%. By adding polycarboxylic acid water reducing agent and glycolic acid acidic modifier, the workability and mechanical properties of the magnesium oxychloride cement precursor can be further improved. The water reducing agent helps to reduce the water consumption, improve the density and strength of the material; while the acidic modifier can adjust the pH value of the material, promote the progress of chemical reactions, thereby improving the overall performance of the material.

[0022] Among them, in step S2, the mixing ratio range of the magnesium oxychloride cement precursor and the water treatment plant sludge is 2.3:4.0. By precisely controlling the mixing ratio of the magnesium oxychloride cement precursor and the water treatment plant sludge, the mechanical properties and cost-effectiveness of the material can be balanced. An appropriate mixing ratio can ensure that the non-fired bricks have sufficient strength and durability, while reducing production costs.

[0023] Among them, in step S2, the specific temperature is 20°C-45°C, and the specific humidity is 70%-75%. By maintaining the mixed material in an environment with specific temperature and humidity, the full progress of chemical reactions and the full curing of the material can be ensured. This maintenance environment helps to improve the mechanical properties and stability of the non-fired bricks.

[0024] Among them, in step S2, the specific time is 7 to 14 days. By setting a specific maintenance time of 7 to 14 days, it can ensure that the material completes the chemical reaction and curing process within sufficient time. This time control is crucial for obtaining high-performance non-fired bricks, and can ensure that the material has excellent mechanical properties and durability.

[0025] The present invention mixes the waterworks sludge with magnesium oxychloride cement in a certain proportion, and adds a certain proportion of key modifier A and key modifier B, and can obtain high-performance non-fired bricks. This method is simple to operate and easy to implement on a large scale. The mechanical properties of the obtained high-performance non-fired bricks show a great improvement compared with adding the waterworks sludge alone to magnesium oxychloride cement. It can be used to solve the problem of recycling the waterworks sludge, and at the same time greatly reduce the sludge disposal cost, realize the efficient treatment of the waterworks sludge, and improve the disadvantage that the mechanical properties are greatly reduced after adding the waterworks sludge to magnesium oxychloride cement. The improved non-fired bricks can be used in the construction field, effectively promoting the practical application and commercial promotion of the resource utilization of the tap water plant sludge, and promoting the realization of the dual-carbon strategic goal.

[0026] In the present invention, specific embodiments are also provided as follows Synthesize a mixed sample of waterworks sludge added with modifiers and magnesium oxychloride cement: (1) Weigh 203.33 g of magnesium chloride hexahydrate and 320 g of magnesium oxide, add them to 108 mL of water, then add 3.155 g of polypropylene fiber and 126 g of fly ash, and mechanically stir for 10 min to accelerate mixing. Then, add 1.0515 g of water reducer and 4.206 g of acidic modifier, and finally add 210.33 g of waterworks sludge, and stir for 10 min to accelerate mixing.

[0027] Pour the mixture into a 40mm*40mm*160mm mold, place it in an incubator, cure it at 45°C for one day, and place the solidified component in a constant temperature and humidity curing box, and cure it for 7 days under the conditions of a temperature of 20°C and a humidity of 70%. This sample is a non-fired brick obtained by mixing waterworks sludge and multiple modifiers with magnesium oxychloride cement, denoted as Z1.

[0028] In the present invention, specific comparative examples are also provided as follows A mixed sample of waterworks sludge and magnesium oxychloride cement: (1) Weigh 203.33 of magnesium chloride hexahydrate and 320 g of magnesium oxide, add them to 108 mL of water, and mechanically stir for 10 min to accelerate mixing. Then, add 210.33 g of waterworks sludge, and stir for 10 min to accelerate mixing.

[0029] (2) Pour the mixture into a mold of 40mm * 40mm * 160mm, place it in an incubator, cure it at 45°C for one day, then put the solidified component into a constant temperature and humidity curing box and cure it for 7 days under the conditions of a temperature of 20°C and a humidity of 70%. This sample is recorded as a non-fired brick made of waterworks sludge and magnesium oxychloride cement, denoted as Z2.

[0030] In the present invention, the mixed components of the examples are used as experimental components and tested on a universal testing machine (20kN) (300kN). The experimental steps are as follows: According to the current standard "Testing Methods for the Strength of Cement Mortar (ISO Method)" (GB / T 17671-1999), place the sample to be tested in a 3000 kN electro-hydraulic servo testing machine. Select two sides of the specimen during molding as the flexural surfaces, set the loading rate at 50N / s for loading until the specimen breaks into two halves to obtain the flexural strength. After the flexural test of the magnesium oxychloride cement specimen, each group of specimens forms 2 irregular small test blocks with dimensions of approximately 40 mm × 40 mm × 80 mm. Then, place the prismatic small test blocks in the standard compression fixture centered in sequence, place the standard compression fixture at the position to be tested on the testing machine, and also select two sides of the specimen during molding as the compression surfaces. Set the loading rate at 2.4 kN / s to obtain the compressive strength; the experimental operation steps of the comparative test components are the same as those of the examples, and the results are shown in the following table

[0031] It can be seen that the flexural and compressive strengths of the modified non-fired bricks in the examples are significantly stronger than those of the comparative examples.

[0032] In the present invention, a method for simply preparing high-performance non-fired bricks by adding a key modifier A uses magnesium oxide and magnesium chloride hexahydrate for simple mixing, then adds waterworks sludge and key modifier B, and high-performance non-fired bricks can be obtained through a reasonable curing method. The non-fired bricks have high mechanical properties, and their mechanical properties are significantly improved compared to the non-fired bricks made of waterworks sludge and magnesium oxychloride cement alone. The method of the present invention realizes the efficient treatment of waterworks sludge, obtains high-performance non-fired bricks, effectively promotes the practical application and commercial promotion of the resource utilization of tap water plant sludge, and promotes the realization of the dual-carbon strategic goal.

[0033] The above-disclosed is only a preferred embodiment of the present invention. Of course, it cannot be used to limit the scope of the rights of the present invention. Those of ordinary skill in the art can understand the whole or part of the processes of the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the invention.

Claims

1. A method for preparing high-performance non-fired bricks using water treatment plant sludge, characterized in that, It includes the following steps: S1: Mix magnesium oxide, magnesium chloride and water in proportion, and add the key modifier A to obtain the modified magnesium oxychloride cement precursor; S2: Test the mechanical properties of the magnesium oxychloride cement precursor; S3: Mix the obtained magnesium oxychloride cement precursor with the waterworks sludge, add the key modifier B and mix, and then place it in an environment with a specific temperature and specific humidity for maintenance for a specific time to obtain the non-fired brick with high mechanical properties.

2. The method for preparing a high-performance non-fired brick using waterworks sludge according to claim 1, wherein in step S1, the magnesium chloride is magnesium oxide powder, the magnesium oxide is magnesium chloride hexahydrate, and the molar ratio of the magnesium oxide, magnesium chloride and water mixture is 6 - 12:1:12 - 15.

3. The method for preparing a high-performance non-fired brick using waterworks sludge according to claim 2, wherein in step S1, the key modifier A is coal ash powder and polypropylene fiber, the grade of the coal ash powder is greater than 120 mesh, the content of the coal ash powder added is 10% - 30%, the diameter of the polypropylene fiber is 33μm, the length is 12mm, and the content of the polypropylene fiber added is 0.25% - 1%.

4. The method for preparing a high-performance non-fired brick using waterworks sludge according to claim 3, wherein in step S2, the key modifier B is a water reducing agent and an acidic modifier, the water reducing agent is polycarboxylic acid, the acidic modifier is glycolic acid, the content of the water reducing agent added is 0.5% - 2%, and the content of the glycolic acid added is 0.5% - 2.5%.

5. The method for preparing a high-performance non-fired brick using waterworks sludge according to claim 4, wherein in step S2, the mixing ratio range of the magnesium oxychloride cement precursor and the waterworks sludge is 2.3:4.

0.

6. The method for preparing a high-performance non-fired brick using waterworks sludge according to claim 5, wherein in step S2, the specific temperature is 20°C - 45°C, and the specific humidity is 70% - 75%.

7. The method for preparing a high-performance non-fired brick using waterworks sludge according to claim 6, wherein in step S2, the specific time is 7 days to 14 days.

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