A slow-release phosphorus removal material and its preparation method and application

Abstract

The present application relates to the technical field of slow-release phosphorus removal materials, and specifically discloses a slow-release phosphorus removal material and its preparation method and application. A slow-release phosphorus removal material is made of the following raw materials in parts by weight: 95-105 parts of harmless aluminum ammonium alum slag; 1-3 parts of activator; 5-8 parts of curing agent; 2-3 parts of water; its preparation method is: mixing and grinding the harmless aluminum ammonium alum slag and the activator to obtain aluminum-based micropowder; mixing the aluminum-based micropowder with the curing agent and water and laying them in a mold, cold-pressing and forming a prefabricated embryo; hot-pressing and sintering the prefabricated embryo, first raising the temperature to 300-400℃ within 30min and keeping it warm for 4-6min, then raising it to 500-600℃ within 20min and keeping it warm for 4-6min, and demolding after cooling to obtain the slow-release phosphorus removal material. When used, the slow-release phosphorus removal material of the present application can not only form an organic synergy of chemical phosphorus removal and physical adsorption phosphorus removal, combining the advantages of chemical and physical methods, but also can achieve the effect of slowly releasing aluminum, thereby improving the utilization rate of aluminum ions in the phosphorus removal process and the sustainability of phosphorus removal.

Description

Technical Field

[0001] The present application relates to the technical field of slow-release phosphorus removal materials, and more specifically, to a slow-release phosphorus removal material and a preparation method and application thereof. Background Art

[0002] Eutrophication is one of the common water pollution phenomena. It not only affects the water quality and reduces the transparency of water, but also seriously damages the ecological environment of water. The main cause of eutrophication of water is the excessive phosphorus in the water. Therefore, reducing the phosphorus concentration in the water is one of the effective means to prevent eutrophication of water.

[0003] At present, China has explored a series of relatively mature phosphorus-containing wastewater treatment models represented by biological / ecological combination technologies. However, according to the operation survey results of the built sewage treatment facilities, due to the lack of technical reserves and stricter emission standards, the sewage treatment terminal treatment efficiency is low and the effluent quality exceeds the standard. At present, the use of aluminum-based adsorption materials for phosphorus removal has been widely studied. Aluminum-based compound phosphorus removal has the advantages of stable effluent, simple process flow, and economic benefits.

[0004] As an important secondary resource containing aluminum, aluminum ammonium alum residue can be used as a raw material for the production of aluminum flocculants and water purifiers. The principle is that aluminum ammonium alum residue is deeply washed to extract beryllium to obtain harmless aluminum ammonium alum residue, which is further roasted and the roasted product is acid-dissolved to prepare polyaluminum chloride, which can be used as a water purifier. However, when the water purifier material obtained by this method is used for wastewater phosphorus removal, it has the disadvantages of slow aluminum salt floc formation, light flocs, and slow sedimentation rate. The prior art document (CN110304703 B) modifies and calcines aluminum ash by adding nano-magnesium carbonate, aluminum oxide, and calcium carbonate to generate a polyaluminum chloride water purifier product with stronger adsorption capacity and good stability, but the calcination temperature is as high as over 1400°C, which easily leads to high energy consumption and greatly increases the production cost; the prior art document (CN 111085166 B) provides a new method for preparing phosphorus removal adsorption materials, which has a very good effect on phosphorus adsorption, but this method uses industrial waste gas ash and coal gangue as the main raw materials, and fails to realize the resource utilization of aluminum-based hazardous waste.

[0005] Therefore, it is urgent to propose a solution to solve the above technical problems. Summary of the invention

[0006] In order to improve the utilization rate of aluminum ions in harmless aluminum ammonium alum slag, bring about better phosphorus removal effect, and achieve more excellent environmental protection effect, the present application provides a slow-release phosphorus removal material and its preparation method and application.

[0007] In the first aspect, the present application provides a slow-release phosphorus removal material, which adopts the following technical solution:

[0008] A slow-release phosphorus removal material is prepared from the following raw materials in parts by weight:

[0009] 95-105 parts of harmless aluminum ammonium alum residue;

[0010] 1-3 parts of stimulant;

[0011] 5-8 parts of curing agent;

[0012] 2-3 parts water;

[0013] The activator is one or a combination of silicate, aluminate or calcium salt;

[0014] The curing agent is cement ash;

[0015] After mixing the raw materials, they are cold-pressed in a mold to obtain a prefabricated body, and then the prefabricated body is hot-pressed and sintered. During the hot-pressing and sintering process, the temperature is first raised to 300-400°C within 30 minutes and kept warm for 4-6 minutes, then raised to 500-600°C within 20 minutes and kept warm for 4-6 minutes, and finally cold demolding is performed to obtain a slow-release phosphorus removal material.

[0016] By adopting the above technical scheme, since harmless aluminum ammonium alum slag is used as the main raw material, it contains a large amount of aluminum components and has a significant effect on phosphorus removal. By adding chemical stimulants, its function is to generate new aluminum-based minerals attached to the surface, blocking the pathway of aluminum active ion reaction, reducing the activity of aluminum, and quickly slowing down the reaction rate, achieving the effect of slowly releasing aluminum, thereby improving the utilization rate of aluminum ions in the phosphorus removal process and the sustainability of phosphorus removal.

[0017] The above-mentioned slow-release phosphorus removal material can be directly placed in phosphorus-containing wastewater, and the OH- or H+ in the wastewater is used for surface corrosion, so that the Al in the material is released into the water to form aluminum ions, thereby achieving the purpose of slow-release aluminum; the aluminum ions react with phosphate or hydrogen phosphate to precipitate, thereby achieving the purpose of capturing phosphorus, and it is highly practical. Moreover, after the harmless aluminum ammonium alum slag is chemically activated by an activator, it is heated, bonded and shaped under the action of a curing agent to form a multi-porous phosphorus capture material that can be directly used for wastewater phosphorus removal. In this way, the obtained slow-release phosphorus removal material can form an organic synergy of chemical phosphorus removal and physical adsorption phosphorus removal when used, and has the advantages of both chemical and physical methods, thereby greatly improving the phosphorus removal efficiency and simplifying the phosphorus removal steps.

[0018] At the same time, the precipitate obtained from phosphorus removal contains a large amount of phosphates, mainly aluminum released into the sewage to form aluminum ions, which react chemically with phosphate and hydrogen phosphate to form precipitates. This phosphorus-rich precipitate is collected and processed into phosphate fertilizer required for municipal garden plants and flowers, realizing the full-process resource closed loop of "production-use-recycling and reuse" of slow-release phosphorus removal materials. It is an economical, widely applicable and environmentally friendly slow-release phosphorus removal material.

[0019] Preferably, the raw material is further added with 1-4 parts by weight of a functional additive, and the functional additive is prepared by the following method:

[0020] S1, taking methyltrioxysilane and ethyl orthosilicate, mixing them, then adding dimethyldiethoxysilane and anhydrous ethanol solution to mix, adding hydrochloric acid to mix and react, and then adding ammonia water to mix and react to obtain a functional gel;

[0021] S2, mixing the basalt fiber with the functional gel obtained in step S1, drying and then subjecting to high temperature treatment to obtain a functional additive.

[0022] By adopting the above technical scheme, in the preparation of the functional additive, a functional gel containing a Si-OC structure is first prepared, and then basalt fibers are dispersed in the functional gel. Then, during the high-temperature treatment process, the pores of the functional gel are increased and enlarged, and a mutually adhered structure is formed with the basalt fibers. At the same time, the basalt fibers will also undergo structural changes at high temperatures, and their own pore structure will expand into large pores, thereby forming a better adaptation with the changes in the above-mentioned functional gel. When the obtained functional additive is applied to the slow-release phosphorus removal material, it can form an excellent coordination system with the harmless aluminum ammonium alum slag, bringing about a good optimization of the uniform distribution of the micropore structure in the slow-release phosphorus removal material, thereby making the slow-release phosphorus removal material have a better effect and stability in slowly releasing aluminum ions in the water body, and the overall phosphorus removal effect is significantly enhanced.

[0023] Preferably, in step S2, the weight ratio of basalt fiber to functional gel is (0.03-0.05):1.

[0024] By adopting the above technical scheme, when the basalt fiber and functional gel in the above proportion are mixed and applied, the changes that occur between the two during the high-temperature treatment process can produce strong adaptability, and the obtained functional additives can also be more suitable for combining with the harmless aluminum ammonium alum slag when used, thereby ensuring that the obtained slow-release phosphorus removal material has a uniformly distributed microporous structure, and the application of slow-release chloride ions has an excellent and stable effect, and the phosphorus removal effect is also stronger.

[0025] Preferably, in step S2, the high temperature treatment process is to first increase the temperature to 150-200°C at 3-5°C / min, keep it warm for 15-25 minutes, then increase the temperature to 400-450°C at 2-3°C / min, keep it warm for 25-35 minutes, and finally increase the temperature to 1000-1100°C at 3-5°C / min, and keep it warm for 100-120 minutes.

[0026] By adopting the above technical scheme, the above high-temperature treatment process can cause the basalt fiber and the functional gel to undergo relatively stable structural changes, and ensure that less fracture damage occurs during the process, thereby ensuring that the obtained functional additive can exert a relatively excellent and stable corresponding effect in the mixed system of the slow-release phosphorus removal material after application.

[0027] Preferably, the activator is one or a combination of silicate, aluminate or calcium salt;

[0028] The curing agent is cement ash.

[0029] By adopting the above technical scheme, the selection of the above activators and curing agents are suitable for the preparation of slow-release phosphorus removal materials, and can stably exert their own effects, thereby obtaining slow-release phosphorus removal materials with excellent and stable application quality.

[0030] In a second aspect, the present application provides a method for preparing a slow-release phosphorus removal material, using the following technical solution:

[0031] A method for preparing a slow-release phosphorus removal material comprises the following steps:

[0032] (1) Prepare raw materials including harmless aluminum ammonium alum slag, activator, curing agent and water according to the proportion;

[0033] (2) mixing and grinding the harmless aluminum ammonium alum residue in step (1) and an activator to obtain aluminum-based micropowder;

[0034] (3) mixing the aluminum-based micropowder in step (2) with a curing agent and water, laying the mixture in a mold, and cold pressing the mixture to obtain a prefabricated embryo;

[0035] (4) The prefabricated body in step (3) is subjected to hot pressing and sintering. The temperature is first raised to 300-400° C. within 30 minutes and kept at this temperature for 4-6 minutes. Then, the temperature is raised to 500-600° C. within 20 minutes and kept at this temperature for 4-6 minutes. After cooling, the prefabricated body is demolded to obtain a slow-release phosphorus removal material.

[0036] By adopting the above technical scheme, in the operation of the above preparation method, the harmless aluminum ammonium alum slag is first chemically activated, and then heated, bonded and shaped to form a multi-void phosphorus capture material. The overall operation is convenient, the process is simple, and it is convenient for large-scale industrial production. At the same time, during the hot pressing and sintering process, the selection and control of the above temperature and time can ensure that the obtained slow-release phosphorus removal material has a rough outer surface and a uniform distribution of microporous structures, and then can slowly release aluminum ions in the water body, with a better phosphorus removal effect. Moreover, the slow-release phosphorus removal material obtained by the above preparation method is made by mold processing, and can be used in the sedimentation tank before the sewage is discharged through modular filling. After the material is consumed, the pool can be simply cleared or the modular material can be directly refilled to continue to remove phosphates in the sewage. The operation is simple and convenient, and no personnel operation and maintenance are required until the material is consumed, and there is no personnel cost, no mechanical equipment cost, and no power consumption cost.

[0037] Preferably, the particle size of the harmless aluminum ammonium alum slag is ≤6 mm, and the mass proportion of the aluminum-based micropowder with a particle size of ≤0.074 mm is ≥90%.

[0038] By adopting the above technical scheme, the particle size of the harmless aluminum ammonium alum slag is selected so that it can be quickly and fully activated during the mixing and grinding process with the activator; and the above particle size and mass ratio selection of the aluminum-based micropowder can not only achieve the excellent slow release of aluminum, but also can be mixed with a curing agent and water in the subsequent processing to form a stable multi-void structure, and finally the sustained-release phosphorus removal material has a rough surface, a uniformly distributed microporous structure, and a better overall application quality.

[0039] Preferably, the mold in step (3) is in the shape of a rectangular grid, with a thickness of 3-5 cm and a mesh size of ≥100 meshes.

[0040] By adopting the above technical solution, the slow-release phosphorus removal material obtained by the mold of the above specifications can exert a stable and better phosphorus removal effect on phosphorus-containing wastewater when used, and the above modular slow-release phosphorus removal material is also easy to load and replace, and has better usability.

[0041] In a third aspect, the present application provides an application of a slow-release phosphorus removal material in wastewater phosphorus removal, using the following technical solution:

[0042] The invention discloses an application of a slow-release phosphorus removal material in phosphorus removal from sewage.

[0043] Preferably, the slow-release phosphorus removal material is placed in a sedimentation tank before sewage discharge, and is stacked in multiple layers horizontally or spaced vertically at an angle of 45° along the direction of water flow.

[0044] By adopting the above technical solution, the slow-release phosphorus removal material is applied to the phosphorus removal of sewage, and is used in the above setting mode, the chemical phosphorus removal and physical adsorption phosphorus removal brought by the application of the slow-release phosphorus removal material can have better synergy, and the overall treatment effect is excellent. At the same time, after the modular slow-release phosphorus removal material is used and consumed, the phosphorus-rich precipitate obtained after phosphorus removal can be collected and processed to make phosphorus fertilizer required for municipal garden plants and flowers.

[0045] In summary, this application has the following beneficial effects:

[0046] 1. This application is based on the resource recycling of harmless aluminum ammonium alum slag. After the dried harmless aluminum ammonium alum slag is chemically activated, it is heated, bonded and shaped to form a multi-porous phosphorus capture and slow-release phosphorus removal material. Through the organic synergy of chemical phosphorus removal and physical adsorption phosphorus removal, while taking into account the effect of slow release of aluminum, the utilization rate of aluminum ions in the phosphorus removal process and the sustainability of phosphorus removal are improved, thereby exerting an excellent phosphorus removal effect;

[0047] 2. The slow-release phosphorus removal material of the present application can be used by modular loading into the sedimentation tank before the sewage is discharged. After the material is consumed, the tank can be simply cleaned or the modular material can be directly reloaded to continue to remove phosphates in the sewage. The operation is simple and convenient. No personnel operation and maintenance are required until the material is consumed. There is no personnel cost, no mechanical equipment cost, and no power consumption cost.

[0048] 3. After the slow-release phosphorus removal material of this application is used to remove phosphorus, the phosphate precipitate produced can be processed again into phosphorus fertilizer required for municipal garden plants and flowers, and can also be processed as an organic fertilizer additive and used as a compound fertilizer for seedling planting. The disposal route is clear and no secondary pollution is generated. It is an environmentally friendly functional material;

[0049] 4. The present application further adds specially prepared functional additives to the slow-release phosphorus removal material, and forms an excellent coordination system with the harmless aluminum ammonium alum slag, thereby achieving good optimization of the uniform distribution of the micropore structure in the slow-release phosphorus removal material, thereby making the slow-release phosphorus removal material more effective and stable in slowly releasing aluminum ions in the water, and significantly enhancing the overall phosphorus removal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a scanning electron microscope image of the slow-release phosphorus removal material obtained in Example 1 of the present application and Comparative Example 1;

[0051] Figure 2 The aluminum ion concentration changes in water bodies of the slow-release phosphorus removal materials obtained in Example 1 of the present application and in Comparative Example 2. DETAILED DESCRIPTION

[0052] The present application is further described in detail below in combination with preparation examples, embodiments and comparative examples.

[0053] Unless otherwise specified, the raw materials used in the preparation examples, embodiments and comparative examples of the present application are commercially available:

[0054] The harmless aluminum ammonium alum residue is obtained by deep water washing and extracting beryllium from the raw material aluminum ammonium alum residue;

[0055] Cement ash was purchased from Shanghai Jingtu Industrial Co., Ltd. Deconch Cement Ash 425R;

[0056] Basalt fiber was purchased from Taian Haosong Fiber Co., Ltd., model xwy-16.

[0057] Preparation examples of raw materials and / or intermediates

[0058] Preparation Example 1

[0059] A functional additive is prepared by the following method:

[0060] S1, taking methyltrioxysilane and ethyl orthosilicate, mixing them, then adding dimethyldiethoxysilane and anhydrous ethanol solution to mix, adding hydrochloric acid to mix and react, and then adding ammonia water to mix and react to obtain a functional gel;

[0061] S2. Mix the basalt fiber with the functional gel obtained in step S1, dry and perform high-temperature treatment, first heat to 175°C at 4°C / min, keep warm for 20 minutes, then heat to 425°C at 2.5°C / min, keep warm for 30 minutes, and finally heat to 1050°C at 4°C / min, keep warm for 110 minutes, to obtain a functional additive.

[0062] Note: In the above operation, the weight ratio of methyltrioxysilane, ethyl orthosilicate and dimethyldiethoxysilane is 2:3:4; the anhydrous ethanol solution is obtained by mixing anhydrous ethanol and distilled water in a weight ratio of 4:3; the weight ratio of anhydrous ethanol solution and dimethyldiethoxysilane is 5:2; hydrochloric acid is added until the pH of the mixed solution is 3; the molar ratio of ammonia water and dimethyldiethoxysilane is 1:1; the weight ratio of basalt fiber and functional gel is 0.04:1.

[0063] Preparation Example 2

[0064] A functional additive, which is different from Preparation Example 1 in that, in step S2, the high-temperature treatment process is to first increase the temperature to 150°C at 3°C / min, keep it warm for 25 minutes, then increase the temperature to 400°C at 2°C / min, keep it warm for 35 minutes, and finally increase the temperature to 1000°C at 3°C / min, and keep it warm for 120 minutes.

[0065] Preparation Example 3

[0066] A functional additive, which is different from Preparation Example 1 in that, in step S2, the high-temperature treatment process is to first increase the temperature to 200°C at 5°C / min, keep it warm for 15 minutes, then increase the temperature to 450°C at 3°C / min, keep it warm for 25 minutes, and finally increase the temperature to 1100°C at 5°C / min, and keep it warm for 100 minutes.

[0067] Preparation Example 4

[0068] A functional additive, which is different from Preparation Example 1 in that the weight ratio of basalt fiber to functional gel is 0.03:1.

[0069] Preparation Example 5

[0070] A functional additive, which is different from Preparation Example 1 in that the weight ratio of basalt fiber to functional gel is 0.05:1.

[0071] Example

[0072] Example 1

[0073] A slow-release phosphorus removal material, the raw materials used in its preparation and their corresponding weights are shown in Table 1, and it is prepared by the following steps:

[0074] (1) Prepare raw materials including harmless aluminum ammonium alum slag, activator, curing agent and water according to the proportion;

[0075] (2) mixing and grinding the harmless aluminum ammonium alum residue in step (1) and an activator to obtain aluminum-based micropowder;

[0076] (3) mixing the aluminum-based micropowder in step (2) with a curing agent and water, laying the mixture in a mold, and cold pressing the mixture to obtain a prefabricated embryo;

[0077] (4) The prefabricated body in step (3) is subjected to hot pressing and sintering. The temperature is first raised to 350° C. within 20 minutes and kept at this temperature for 5 minutes. Then, the temperature is raised to 550° C. within 15 minutes and kept at this temperature for 5 minutes. After cooling, the prefabricated body is demolded to obtain a slow-release phosphorus removal material.

[0078] Note: In the above operation, the activator is sodium silicate, the curing agent is cement ash; the particle size of the harmless aluminum ammonium alum slag is 5.5 mm, and the mass proportion of the aluminum-based micropowder with a particle size of ≤0.074 mm is 95%; the mold in step (3) is a rectangular grid with a thickness of 4 cm and a mesh size of 100 mesh.

[0079] Example 2-3

[0080] A slow-release phosphorus removal material, which is different from Example 1 in that the raw materials used in its preparation and their corresponding weights are shown in Table 1.

[0081] Table 1 Raw materials used in the preparation of slow-release phosphorus removal materials in Examples 1-3 and their weight portions (kg / portion)

[0082]

[0083] Example 4

[0084] A slow-release phosphorus removal material, which is different from Example 1 in that step (4) is specifically configured as follows: the prefabricated embryo body in step (3) is subjected to hot pressing and sintering, the temperature is first raised to 300° C. within 20 minutes and kept warm for 6 minutes, then raised to 50° C. within 15 minutes and kept warm for 6 minutes, and then demolded after cooling to obtain the slow-release phosphorus removal material.

[0085] Example 5

[0086] A slow-release phosphorus removal material, which is different from Example 1 in that step (4) is specifically configured as follows: the prefabricated embryo body in step (3) is subjected to hot pressing sintering, the temperature is first raised to 400° C. within 20 minutes and kept at this temperature for 4 minutes, then raised to 600° C. within 15 minutes and kept at this temperature for 4 minutes, and then demolded after cooling to obtain the slow-release phosphorus removal material.

[0087] Example 6

[0088] A slow-release phosphorus removal material, which is different from Example 1 in that the mold in step (3) is in the shape of a rectangular grid with a thickness of 3 cm and a mesh size of 100.

[0089] Example 7

[0090] A slow-release phosphorus removal material, which is different from Example 1 in that the mold in step (3) is in the shape of a rectangular grid with a thickness of 5 cm and a mesh size of 100.

[0091] Example 8

[0092] A slow-release phosphorus removal material is different from Example 1 in that 2.5 parts by weight of a functional additive are also added to the raw material, the functional additive is obtained from Preparation Example 1, and the functional additive is added together with a curing agent.

[0093] Example 9

[0094] A slow-release phosphorus removal material, which is different from Example 8 in that the weight portion of the functional additive added is 1 part.

[0095] Example 10

[0096] A slow-release phosphorus removal material, which is different from Example 8 in that the weight portion of the functional additive added is 4 parts.

[0097] Embodiment 11

[0098] A slow-release phosphorus removal material, which is different from Example 8 in that the functional additive is obtained from Preparation Example 2.

[0099] Example 12

[0100] A slow-release phosphorus removal material, which is different from Example 8 in that the functional additive is obtained from Preparation Example 3.

[0101] Embodiment 13

[0102] A slow-release phosphorus removal material, which is different from Example 8 in that the functional additive is obtained from Preparation Example 4.

[0103] Embodiment 14

[0104] A slow-release phosphorus removal material, which is different from Example 8 in that the functional additive is obtained from Preparation Example 5.

[0105] Embodiment 15

[0106] A slow-release phosphorus removal material, which is different from Example 8 in that the functional auxiliary agent is replaced by a functional gel.

[0107] Example 16

[0108] A slow-release phosphorus removal material, which is different from Example 8 in that the functional additives are replaced by basalt fibers.

[0109] Comparative Example

[0110] Comparative Example 1

[0111] A slow-release phosphorus removal material, which is different from Example 1 in that step (4) is specifically configured as follows: hot-pressing and sintering the prefabricated embryo in step (3), raising the temperature to 550° C. within 35 minutes and maintaining the temperature for 5 minutes, and demolding after cooling to obtain the slow-release phosphorus removal material.

[0112] Comparative Example 2

[0113] A slow-release phosphorus removal material, which is different from Example 1 in that it is prepared by the following steps:

[0114] (1) preparing raw materials including harmless aluminum ammonium alum slag, curing agent and water according to the proportion;

[0115] (2) mixing the harmless aluminum ammonium alum residue in step (1) with a curing agent and water, laying the mixture in a mold, and cold pressing the mixture to obtain a prefabricated embryo;

[0116] (3) The prefabricated body in step (2) is subjected to hot pressing and sintering. The temperature is first raised to 350° C. within 20 minutes and kept at this temperature for 5 minutes. Then, the temperature is raised to 550° C. within 15 minutes and kept at this temperature for 5 minutes. After cooling, the prefabricated body is demolded to obtain a slow-release phosphorus removal material.

[0117] Application Examples

[0118] Application Example 1

[0119] A slow-release phosphorus removal material is used in wastewater phosphorus removal. The slow-release phosphorus removal material is placed in a sedimentation tank before wastewater discharge, and is stacked in multiple layers horizontally or spaced vertically at an angle of 45 degrees along the water flow direction. The gap between adjacent slow-release phosphorus removal materials is greater than 3 cm.

[0120] Performance testing

[0121] Test samples: The slow-release phosphorus removal materials obtained in Examples 1-16 were used as test samples 1-16, and the slow-release phosphorus removal materials obtained in Comparative Examples 1-2 were used as control samples 1-2.

[0122] Test method: Take the slow-release phosphorus removal material and load it into a 3L reactor. Place it in the manner of Application Example 1. The gap between adjacent slow-release phosphorus removal materials is 5cm. Place three pieces in the reactor, then add 2L of the water sample to be treated, and circulate the water sample in the reactor through a water pump. In the above operation, first determine the initial orthophosphate concentration of the water sample to be treated, recorded as A1; after circulating for 7 hours, determine the initial orthophosphate concentration of the water sample to be treated again, recorded as A2; finally calculate the orthophosphate removal rate. Among them, the water samples to be treated are selected from a sewage in Yangzhou, Jiangsu (Sewage No. 1) and a sewage in Liling, Hunan (Sewage No. 2), and use test samples 1-16 and control samples 1-2 to complete the above tests on the water samples to be treated, and record the test results in Table 2.

[0123] Table 2 Test results of test samples 1-16 and control samples 1-2

[0124]

[0125] Depend on Figure 1 As can be seen from (a) in Example 1, the phosphorus-removing sustained-release material obtained by the sintering step of the present invention has a rough surface and a uniformly distributed microporous structure; Figure 1 In (b) of the comparative example 1, the phosphorus removal slow-release material obtained by directly heating to the sintering temperature without keeping at 300-400°C for 4-6 minutes has a rough outer surface, presents a regular agglomeration morphology, and does not form an effective microporous structure. It can be seen that in the preparation of the phosphorus removal slow-release material, the formation of multi-pores to capture phosphorus plays a key role in controlling the formation of pores.

[0126] Depend on Figure 2It can be seen that the slow-release material obtained in Example 2 slowly releases aluminum ions in the water body. In contrast, the slow-release phosphorus removal material obtained in Example 2 quickly releases aluminum ions in the initial stage of being placed in the water body, and is basically completely released within 3 hours. A large amount of aluminum ions in the water body fail to react with phosphorus in time, resulting in a waste of aluminum, reducing the service life of the material module, and making it difficult to effectively remove phosphorus, resulting in excessive phosphorus in the effluent.

[0127] Combining Examples 1-3 and Comparative Example 2 and Table 2, it can be seen that if no activator is used, the orthophosphate removal rate of the wastewater obtained by the above test of the slow-release phosphorus removal material is significantly reduced. Figure 2 Based on the above analysis, it can be seen that the use of the activator has a significant effect on the effective utilization of aluminum in the harmless aluminum ammonium alum slag, which can ensure that the slow-release phosphorus removal material obtained in this application not only has a slow-release characteristic, but also can effectively utilize the harmless aluminum ammonium alum slag resources and bring more prominent wastewater phosphorus removal effect.

[0128] Combining Examples 1, 4-5 and Comparative Example 1 and Table 2, it can be seen that the prefabricated embryo body in step (3) is subjected to hot pressing sintering, first the temperature is raised to 300-400°C within 30 minutes and kept warm for 4-6 minutes, and then raised to 500-600°C within 20 minutes and kept warm for 4-6 minutes, which can ensure that the obtained slow-release phosphorus removal material has a rough outer surface and a uniformly distributed microporous structure, and can then slowly release aluminum ions in the water body, thereby having a better phosphorus removal effect; while if in the above operation, the temperature is directly raised to the sintering temperature without being kept warm at 300-400°C for 4-6 minutes, the obtained slow-release phosphorus removal material has a significantly lower orthophosphate removal rate in sewage after testing, and then combined with Figure 2 Based on the above analysis, it can be seen that the above temperature control is particularly important for obtaining a slow-release phosphorus removal material with a special structure.

[0129] It can be seen from Example 1 and Examples 6-7 and Table 2 that the mold in step (3) is in the shape of a rectangular grid with a thickness of 3-5 cm and a mesh size of ≥100 meshes, and the slow-release phosphorus removal material obtained by the mold of the above specifications can exert a stable and better phosphorus removal effect on phosphorus-containing wastewater when used.

[0130] Combining Example 1 and Example 8-14 with Table 2, it can be seen that applying for further adding a specially prepared functional additive to the slow-release phosphorus removal material can further improve the removal rate of orthophosphate in sewage, indicating that the slow-release phosphorus removal material has a better effect and stability in slowly releasing aluminum ions in the water body, and the overall phosphorus removal effect is significantly enhanced. Combining Example 15-16 with Table 2, it can be seen that if any one of the basalt fiber and the functional gel is used alone as a functional additive, it is found that although the orthophosphate removal rate of sewage obtained by the test is increased, the sum of the improvement effects brought by the use of the two alone is far less than the excellent functional additive prepared by the compounding of the two. It can be seen that the special combination of basalt fiber and functional gel can bring a significant improvement effect of 1+1>2, thereby significantly enhancing the phosphorus removal effect of sewage.

[0131] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A slow-release phosphorus removal material, characterized in that: Made from the following raw materials in parts by weight: 95-105 parts of harmless aluminum ammonium alum residue; 1-3 parts of stimulant; 5-8 parts of curing agent; 2-3 parts water; The activator is one or a combination of silicate, aluminate or calcium salt; The curing agent is cement ash; After mixing the raw materials, the prefabricated body is cold-pressed in a mold, and then the prefabricated body is hot-pressed and sintered. During the hot-pressing and sintering process, the temperature is first raised to 300-400°C within 30 minutes and kept warm for 4-6 minutes, then raised to 500-600°C within 20 minutes and kept warm for 4-6 minutes, and finally cooled and demolded to obtain a slow-release phosphorus removal material.

2. The slow-release phosphorus removal material according to claim 1, characterized in that: The raw materials are also added with 1-4 parts by weight of a functional additive, which is prepared by the following method: S1, taking methyltrioxysilane and ethyl orthosilicate, mixing them, then adding dimethyldiethoxysilane and anhydrous ethanol solution to mix, adding hydrochloric acid to mix and react, and then adding ammonia water to mix and react to obtain a functional gel; S2, mixing the basalt fiber with the functional gel obtained in step S1, drying and then subjecting to high temperature treatment to obtain a functional additive.

3. The slow-release phosphorus removal material according to claim 2, characterized in that: In step S2, the weight ratio of basalt fiber to functional gel is (0.03-0.05):

1.

4. The slow-release phosphorus removal material according to claim 2, characterized in that: In step S2, the high temperature treatment process is to first increase the temperature to 150-200°C at 3-5°C / min, keep it warm for 15-25 minutes, then increase the temperature to 400-450°C at 2-3°C / min, keep it warm for 25-35 minutes, and finally increase the temperature to 1000-1100°C at 3-5°C / min, and keep it warm for 100-120 minutes.

5. The method for preparing the slow-release phosphorus removal material according to claim 1, characterized in that: The following steps are involved: (1) Prepare raw materials including harmless aluminum ammonium alum slag, activator, curing agent and water according to the proportion; (2) mixing and grinding the harmless aluminum ammonium alum residue in step (1) and an activator to obtain aluminum-based micropowder; (3) mixing the aluminum-based micropowder in step (2) with a curing agent and water, laying the mixture in a mold, and cold pressing the mixture to obtain a prefabricated embryo; (4) The prefabricated body in step (3) is subjected to hot pressing and sintering. The temperature is first raised to 300-400° C. within 30 minutes and kept at this temperature for 4-6 minutes. Then, the temperature is raised to 500-600° C. within 20 minutes and kept at this temperature for 4-6 minutes. After cooling, the prefabricated body is demolded to obtain a slow-release phosphorus removal material.

6. The method for preparing the slow-release phosphorus removal material according to claim 5, characterized in that: The particle size of the harmless aluminum ammonium alum slag is ≤6mm, and the mass proportion of the aluminum-based micropowder with a particle size of ≤0.074mm is ≥90%.

7. The method for preparing the slow-release phosphorus removal material according to claim 5, characterized in that: The mold of step (3) is in the shape of a rectangular grid, with a thickness of 3-5 cm and a mesh size of ≥100 meshes.

8. Use of the slow-release phosphorus removal material according to claim 1 in phosphorus removal from sewage.

9. The use of the slow-release phosphorus removal material according to claim 8 in wastewater phosphorus removal, characterized in that: The slow-release phosphorus removal material is placed in a sedimentation tank before sewage discharge, and is stacked in multiple layers horizontally or spaced vertically at an angle of 45 degrees along the water flow direction.

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