A solid waste-based sludge solidifying agent and preparation method thereof

Abstract

The present application relates to the field of solid waste treatment, and in particular to a solid waste-based sludge solidifying agent and a preparation method thereof; the raw materials of the sludge solidifying agent include: steelmaking solid waste, straw ash, phosphoric acid industrial solid waste, garbage combustion slag, a composite reinforcing agent, and the rest are solid carriers; the steelmaking solid waste includes steel slag; the chemical composition of the phosphoric acid industrial solid waste includes Ca; the method includes: first screening and second screening of the steelmaking solid waste, garbage combustion slag and solid carrier respectively to obtain corresponding waste undersize; alkalizing the phosphoric acid industrial solid waste to obtain alkalized solid waste; drying the straw ash and the alkalized solid waste respectively, and then second screening to obtain corresponding waste undersize; mixing the undersizes and the composite reinforcing agent to obtain the sludge solidifying agent; by using steelmaking solid waste, straw ash, phosphoric acid industrial solid waste, garbage combustion slag and the composite reinforcing agent, the resilience modulus and CBR value of the sludge can be comprehensively improved while improving the solidification strength of the sludge, and the strength loss after immersion can be reduced.

Description

Technical Field

[0001] The present application relates to the field of solid waste treatment, and in particular to a solid waste-based sludge solidifying agent and a preparation method thereof. Background Art

[0002] With the development of economy and society, the impact of human activities on natural water bodies has gradually increased, causing a rapid increase in solid and semi-solid accumulation in the water bodies, resulting in a large amount of silt at the bottom of the water bodies. With the rapid advancement of water conservancy project construction, water transport engineering construction, river and lake management projects and urban ecological environment management projects, this type of silt has been excavated, resulting in a large amount of waste silt during the construction process.

[0003] At present, the treatment methods for sludge include landfill, incineration, composting, solidification, etc. Among them, solidification is to mix sludge with corresponding solidifying agents to solidify, thereby improving the mechanical properties of sludge and reducing the water content of sludge, so that it can replace natural soil for site backfill. At the same time, with the progress of human activities, a large amount of waste materials such as chemical industry waste, garbage disposal residues, and construction waste are generated. If these wastes can be treated and used to treat sludge, waste can be turned into treasure, so as to achieve the purpose of resource utilization of waste and waste treatment.

[0004] However, since these wastes are used alone as sludge solidifying agents, it is difficult to meet the standard usage requirements. Therefore, how to provide a sludge solidifying agent composed of multiple wastes to improve the solidification strength of the sludge while comprehensively improving the sludge rebound modulus, CBR value and reducing the strength loss after immersion in water to meet the standard usage requirements is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The present application provides a solid waste-based sludge solidifying agent and a preparation method thereof, in order to solve the technical problem that the sludge solidifying agent composed of waste in the prior art is difficult to improve the solidification strength of the sludge while comprehensively improving the rebound modulus and CBR value of the sludge and reducing the strength loss after immersion in water.

[0006] In a first aspect, the present application provides a solid waste-based sludge solidifying agent, wherein the raw materials of the sludge solidifying agent include, by mass fraction: steelmaking solid waste: 25% to 40%, straw ash: 20% to 30%, phosphoric acid industrial solid waste: 15% to 35%, garbage combustion slag: 10% to 30%, composite reinforcing agent: 2% to 5%, and the rest is a solid carrier;

[0007] Wherein, the steelmaking solid waste includes steel slag;

[0008] The chemical composition of the phosphoric acid industrial solid waste includes Ca;

[0009] The composite reinforcing agent is used to enhance the solidification strength of the sludge solidifying agent.

[0010] Optionally, the mass ratio of the steel slag to the steelmaking solid waste is ≥80%.

[0011] Optionally, the phosphoric acid industrial solid waste includes phosphogypsum, and the mass ratio of the phosphogypsum to the phosphoric acid industrial solid waste is ≥90%.

[0012] Optionally, the composite reinforcing agent includes an oxidant, an early strength setting accelerator and a gelling agent, and the mass ratio of the oxidant, the early strength setting accelerator and the gelling agent is 1% to 3%: 1% to 3%: 1% to 3%.

[0013] Optionally, the oxidant comprises at least one of potassium permanganate, manganese dioxide and sodium peroxide; and / or

[0014] The early strength accelerator comprises at least one of calcium chloride, sodium silicate and sodium carbonate; and / or

[0015] The gelling agent includes at least one of polyaluminium sulfate, sodium polyacrylate and methyl cellulose.

[0016] Optionally, the mass fraction of the solid carrier to the total weight of the sludge solidifying agent is 5% to 15%.

[0017] Optionally, the solid carrier includes at least one of construction waste, fly ash and red mud.

[0018] In a second aspect, the present application provides a method for preparing the sludge solidifying agent according to the first aspect, the method comprising:

[0019] The steelmaking solid waste, the garbage combustion slag and the solid carrier are respectively subjected to a first screening, and then subjected to a second screening to obtain a steelmaking solid waste undersize, a garbage combustion slag undersize and a solid carrier undersize;

[0020] alkalinizing the phosphoric acid industrial solid waste to obtain alkalinized solid waste;

[0021] The straw ash and the alkalized solid waste are dried respectively, and then the second screening is performed to obtain straw ash undersize and alkalized solid waste undersize;

[0022] The steelmaking solid waste undersize, the garbage combustion slag undersize, the solid carrier undersize, the straw ash undersize, the alkalized solid waste undersize and the composite reinforcing agent are mixed to obtain a sludge solidifying agent.

[0023] Optionally, the mesh size of the first sieve is 1 mm to 3 mm, and the mesh size of the second sieve is 0.1 mm to 0.2 mm.

[0024] In a third aspect, the present application provides a method for using and dosage of a solid waste-based sludge solidifier, comprising using the sludge solidifier described in the first aspect in the solidification stage of preparing sludge fill material, wherein the mass ratio of the sludge solidifier to the sludge is 10% to 20%.

[0025] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0026] The solid waste-based sludge solidifying agent provided in the embodiment of the present application adopts steelmaking solid waste, straw ash, phosphoric acid industrial solid waste, garbage combustion furnace slag and a composite reinforcing agent. Since the straw ash can produce a strong alkaline environment under the hydration conditions of the sludge, and the straw ash itself is a highly active material, it can activate the steel slag component in the steelmaking solid waste, so that the steel slag can undergo a gelling reaction in the sludge, thereby improving the strength of the sludge and reducing the water content of the sludge. At the same time, the Ca in the phosphoric acid industrial solid waste will be hydrolyzed in the sludge to produce Ca 2+ and replace part of the Na on the surface of sludge organic matter through ion exchange + and K + , can effectively reduce the thickness of the double electric layer of organic matter, reduce the influence of organic matter on sludge solidification, improve the solidification strength and reduce the water content of sludge, and reuse the low water content and strong water absorption of garbage combustion slag, which can effectively reduce the water content of sludge. At the same time, the solid carrier serves as the skeleton of solidified sludge to improve the solidification strength of sludge, and then the composite reinforcing agent is used to further improve the solidification strength of sludge to meet the strengthening effect of sludge. Therefore, through steelmaking solid waste, straw ash, phosphoric acid industrial solid waste, garbage combustion slag and composite reinforcing agent, the solidification strength of sludge can be improved while comprehensively improving the rebound modulus and CBR value of sludge and reducing the strength loss after immersion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 A schematic diagram of a process for a method provided in an embodiment of the present application;

[0030] Figure 2A flowchart of the actual application of the method provided in the embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0032] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0033] In one embodiment of the present application, a solid waste-based sludge solidifying agent is provided. The raw materials of the sludge solidifying agent include, by mass fraction: steelmaking solid waste: 25% to 40%, straw ash: 20% to 30%, phosphoric acid industry solid waste: 15% to 35%, garbage combustion slag: 10% to 30%, composite reinforcing agent: 2% to 5%, and the rest is solid carrier;

[0034] Wherein, the steelmaking solid waste includes steel slag;

[0035] The chemical composition of the phosphoric acid industrial solid waste includes Ca;

[0036] The composite reinforcing agent is used to enhance the solidification strength of the sludge solidifying agent.

[0037] In the embodiment of the present application, the positive effect of controlling the mass fraction of steelmaking solid waste to 25% to 40% is that within the range of this mass fraction, since the steel slag component in the steelmaking solid waste is similar to cement, both have certain properties of cementitious materials, but are very low in activity under normal conditions, and the directly obtained particles are large and difficult to handle. Therefore, highly active materials are generally required to stimulate the volcanic ash properties of such cementitious materials under alkaline conditions to generate more hydration products and improve the cementitious properties, thereby improving the solidification strength of the sludge while comprehensively improving the rebound modulus and CBR value of the sludge and reducing the strength loss after immersion in water.

[0038] The positive effect of the straw ash mass fraction of 20% to 30% is that within this mass fraction range, since straw ash is a highly active material and hydration can produce a strong alkaline environment, it can be used to stimulate the potential activity of steel slag in steelmaking solid waste and improve its gelling properties, thereby improving the solidification strength of the sludge while comprehensively improving the sludge's rebound modulus, CBR value and reducing the strength loss after immersion in water.

[0039] The positive effect of the mass fraction of phosphoric acid industrial solid waste is 15% to 35%. Within this mass fraction range, since phosphoric acid industrial solid waste is generally waste from the wet phosphoric acid industry, it contains a large amount of Ca. During the hydrolysis stage, a large amount of Ca 2+ , while Ca 2+ It can replace part of the Na on the surface of sludge organic matter through ion exchange. + and K + , while Ca 2+ The hydration radius is smaller than that of Na + and K + Therefore, it can effectively reduce the thickness of the organic double layer and reduce the influence of organic matter on sludge solidification, thereby improving the solidification strength of the sludge while comprehensively improving the sludge rebound modulus and CBR value and reducing the strength loss after immersion in water.

[0040] The positive effect of the mass fraction of garbage combustion slag being 10% to 30% is that within this mass fraction range, since garbage combustion slag has the characteristics of low moisture content and strong water absorption, it will quickly absorb the moisture of the sludge when added to the sludge, thereby reducing the moisture content of the sludge. At the same time, larger particles of garbage combustion slag can also act as a skeleton together with the solid carrier in the sludge solidification stage, thereby improving the strength of the solidified sludge.

[0041] The positive effect of the composite reinforcing agent having a mass fraction of 2% to 5% is that within the mass fraction range, the composite reinforcing agent can ensure the solidification strength of the sludge in the solidification stage and meet the solidification effect of the sludge solidifying agent.

[0042] Among them, steelmaking solid waste refers to by-products and wastes in the steelmaking process, such as slag or furnace slag.

[0043] Solid waste from the phosphoric acid industry refers to waste generated during the production of phosphoric acid using the wet phosphoric acid process, such as phosphogypsum, phosphate rock and calcium hydrogen phosphate.

[0044] Garbage combustion slag refers to the slag formed by the thorough oxidation, differentiation and passivation of various components during the garbage combustion process. It is mainly composed of glass, metal and various inorganic substances.

[0045] In some optional embodiments, the mass ratio of the steel slag to the steelmaking solid waste is ≥ 80%.

[0046] In the embodiment of the present application, the positive effect of controlling the mass ratio of steel slag to steelmaking solid waste to be ≥80% is that within the range of this mass ratio, the content of steel slag in the steelmaking solid waste can be ensured to be sufficient, thereby ensuring that the steelmaking solid waste can fully gel the sludge and improve the solidification strength of the sludge.

[0047] In some optional embodiments, the phosphoric acid industrial solid waste includes phosphogypsum, and the mass ratio of the phosphogypsum to the phosphoric acid industrial solid waste is ≥ 90%.

[0048] In the embodiment of the present application, the positive effect of controlling the phosphoric acid industry solid waste including phosphogypsum and controlling the mass ratio of phosphogypsum to phosphoric acid industry solid waste ≥ 90% is due to the fact that the phosphoric acid industry often uses a wet phosphoric acid process to produce phosphoric acid, and this method produces 4.5t to 5t of phosphogypsum for every 1t of phosphoric acid produced. The accumulation of phosphogypsum is likely to cause site pollution, and the hydrolysis of phosphogypsum in the sludge produces a large amount of Ca 2+ , by replacing part of the Na on the surface of sludge organic matter through ion exchange + , K + Since the hydration radius of Ca2+ is smaller than that of Na+ and K+, it can effectively reduce the thickness of the double electric layer of organic matter and reduce the influence of organic matter on sludge solidification. At the same time, during the hydration process of phosphogypsum, gypsum will produce a large amount of calcium aluminate crystals. The volume of phosphogypsum powder increases, squeezing the clay particles in the surrounding silt and filling the micropores in the solidified silt, which improves the strength of the solidified silt.

[0049] In some optional embodiments, the composite reinforcing agent includes an oxidant, an early strength setting accelerator and a gelling agent, and the mass ratio of the oxidant, the early strength setting accelerator and the gelling agent is 1% to 3%: 1% to 3%: 1% to 3%.

[0050] In the embodiments of the present application, the specific composition of the composite reinforcing agent is controlled, and the macromolecular organic matter in the sludge is decomposed into small molecules by using an oxidant to reduce the adverse effect of organic matter on solidification, and then the early strength accelerator is used to increase the early gelling strength of the steel slag after activation by straw ash, thereby promoting the gelling properties of the steel slag and ensuring the solidification effect. At the same time, it also has an antifreeze effect, so that the sludge solidifying agent can be used under certain low temperature conditions. Finally, the impurities in the sludge are quickly precipitated by the gelling agent to avoid the influence of larger impurities on the solidification of the sludge.

[0051] In some optional embodiments, the oxidant includes at least one of potassium permanganate, manganese dioxide and sodium peroxide; and / or

[0052] The early strength accelerator comprises at least one of calcium chloride, sodium silicate and sodium carbonate; and / or

[0053] The gelling agent includes at least one of polyaluminium sulfate, sodium polyacrylate and methyl cellulose.

[0054] In the embodiments of the present application, the positive effect of controlling the type of oxidant is that this type of oxidant has a high oxidizing property and can therefore quickly decompose large organic molecules into small molecules, thereby reducing the adverse effects of organic matter on sludge solidification.

[0055] The positive effect of controlling the type of early strength accelerator is that the use of common early strength accelerators can effectively ensure the early strength of the gelling system in the sludge solidifier, while also having the effects of accelerating coagulant and antifreeze.

[0056] The positive effect of controlling the type of gelling agent is that polyaluminium sulfate is a composite high molecular polymer with a large molecular structure and strong adsorption capacity. When it is put into water, the flocs formed are large, the precipitation speed is fast, the activity is high, and the pH value of the water is minimal. Adding polyaluminium sulfate to the sludge can quickly precipitate the impurities in the sludge and reduce the adverse effects of impurities on solidification.

[0057] In some optional embodiments, the mass fraction of the solid carrier to the total weight of the sludge solidifying agent is 5% to 15%.

[0058] In the embodiment of the present application, the positive effect of controlling the mass ratio of the solid carrier to the total weight of the sludge solidifying agent to be 5% to 15% is that within this mass fraction range, it can be ensured that the solid carrier can not only serve as a gelling reaction carrier of the gelling system formed by the steel slag and the composite reinforcing agent, but also serve as the skeleton of the sludge solidifying agent, thereby improving the solidification strength of the sludge.

[0059] In some optional embodiments, the solid carrier includes at least one of construction waste, fly ash and red mud.

[0060] In the embodiments of the present application, by controlling the specific composition of the solid carrier, the properties of construction waste or fly ash can be further utilized to serve as the skeleton and reaction carrier of the sludge solidifying agent, thereby improving the solidification strength of the sludge.

[0061] Construction waste refers to construction-related waste generated during the construction process, such as slag, concrete fragments and brick and tile fragments.

[0062] Based on a general inventive concept, such as Figure 1 and Figure 2 As shown, the present application embodiment also provides a method for preparing a solid waste-based sludge solidifying agent, the method comprising:

[0063] S1. The steelmaking solid waste, the garbage combustion slag and the solid carrier are respectively subjected to a first screening, and then a second screening is performed to obtain a steelmaking solid waste undersize, a garbage combustion slag undersize and a solid carrier undersize;

[0064] S2. alkalinizing the phosphoric acid industrial solid waste to obtain alkalinized solid waste;

[0065] S3. The straw ash and the alkalized solid waste are dried separately, and then the second screening is performed to obtain a straw ash undersize and an alkalized solid waste undersize;

[0066] S4. Mix the steelmaking solid waste undersize, the garbage combustion slag undersize, the solid carrier undersize, the straw ash undersize, the alkalized solid waste undersize and the composite reinforcing agent to obtain a sludge solidifying agent.

[0067] This method is used to prepare the above-mentioned sludge solidifying agent. The specific components of the sludge solidifying agent can refer to the above-mentioned embodiment. Since this method adopts part or all of the technical solutions of the above-mentioned embodiment, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here one by one.

[0068] In the embodiment of the present application, the steelmaking solid waste, garbage combustion slag and solid carrier are first screened to ensure that their respective particle sizes are uniform, and then the phosphoric acid industrial solid waste is alkalized to avoid the acidic substances in the phosphoric acid industrial solid waste from damaging the alkaline environment formed by the straw ash, thereby resulting in the straw ash being unable to fully activate the gelling properties of the steel slag. Finally, the straw ash and the alkalized solid waste are secondly screened to ensure uniform particle size, which facilitates the uniform dispersion of the various components of the sludge solidifier in the sludge, thereby ensuring the uniform solidification of the sludge, and then ensuring the strength of the sludge solidification.

[0069] In some optional embodiments, the particle size of the first sieve is 1 mm to 3 mm, and the particle size of the second sieve is 0.1 mm to 0.2 mm.

[0070] In the embodiment of the present application, the positive effect of controlling the particle size of the first screening to 1mm to 3mm is that within this particle size range, it can ensure that the steelmaking solid waste, garbage combustion slag and solid carrier are in a uniform millimeter-level range of 1mm to 3mm, thereby ensuring their uniform dispersion in the sludge solidifier, promoting uniform sludge solidification, and ensuring the strength of sludge solidification.

[0071] The positive effect of controlling the particle size of the second screening to 0.1mm~0.2mm is that within this particle size range, the particle size of straw ash and alkalized solid waste can be guaranteed to be uniform, thereby ensuring their uniform dispersion in the sludge solidifier, promoting uniform sludge solidification, and ensuring the strength of sludge solidification.

[0072] Based on a general inventive concept, an embodiment of the present application also provides a method and dosage of using a solid waste-based sludge solidifier, including using the sludge solidifier in the solidification stage of preparing sludge fill material, wherein the mass ratio of the sludge solidifier to the sludge is 10% to 20%.

[0073] In the embodiment of the present application, the positive effect of controlling the mass ratio of the silt solidifying agent to the silt to be 10% to 20% is that within the range of the mass ratio, the silt can be fully solidified by the silt solidifying agent, so that the silt can meet the strength requirements of the fill material after solidification.

[0074] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0075] Example 1

[0076] A solid waste-based sludge solidifying agent, wherein the raw materials of the sludge solidifying agent include, by mass fraction: steelmaking solid waste: 40%, straw ash: 22%, phosphoric acid industry solid waste: 15%, garbage combustion slag: 15%, composite reinforcing agent: 3%, solid carrier: 5%;

[0077] Among them, steelmaking solid waste includes steel slag;

[0078] The chemical composition of solid wastes from phosphoric acid industry includes Ca;

[0079] The composite reinforcing agent is used to enhance the curing strength of the sludge solidifying agent.

[0080] The mass ratio of steel slag to steelmaking solid waste is ≥80%.

[0081] The solid waste from phosphoric acid industry is phosphogypsum, and the mass ratio of phosphogypsum to solid waste from phosphoric acid industry is ≥90%.

[0082] The composite reinforcing agent comprises an oxidant, an early strength coagulant and a gelling agent, and the mass ratio of the oxidant, the early strength coagulant and the gelling agent is 1:1:1.

[0083] The oxidizing agent is potassium permanganate; and

[0084] The early strength accelerator is calcium chloride; and

[0085] The gelling agent is polyaluminium sulfate.

[0086] A method for preparing a solid waste-based sludge solidifying agent, the method comprising:

[0087] S1. The steelmaking solid waste, the garbage combustion slag and the solid carrier are first screened, the undersize is removed for ball milling, and then the second screening is performed to obtain the steelmaking solid waste undersize, the garbage combustion slag undersize and the solid carrier undersize;

[0088] S2. alkalinizing the phosphoric acid industrial solid waste to obtain alkalinized solid waste;

[0089] S3. The straw ash and the alkalized solid waste are dried, and then a second screening is performed to obtain a straw ash undersize and an alkalized solid waste undersize;

[0090] S4. Mix steelmaking solid waste screenings, garbage combustion slag screenings, solid carrier screenings, straw ash screenings, alkalized solid waste screenings and composite enhancers to obtain a sludge solidifying agent.

[0091] The particle size of the first sieve is 2 mm, and the particle size of the second sieve is 0.15 mm.

[0092] The invention discloses a use of a solid waste-based sludge solidifying agent, comprising using the sludge solidifying agent in the solidification stage of preparing fill material from sludge, wherein the mass ratio of the sludge solidifying agent to the sludge is 10%.

[0093] Example 2

[0094] Comparing Example 2 with Example 1, the difference between Example 2 and Example 1 is:

[0095] A solid waste-based sludge solidifying agent comprises, by mass fraction, raw materials of the sludge solidifying agent including: 30% of steelmaking solid waste, 22% of straw ash, 15% of phosphoric acid industrial solid waste, 20% of garbage combustion slag, 3% of composite reinforcing agent and 10% of solid carrier.

[0096] The mass ratio of the sludge solidifying agent to the sludge is 15%.

[0097] Example 3

[0098] Comparing Example 3 with Example 1, the difference between Example 3 and Example 1 is:

[0099] A solid waste-based sludge solidifying agent, wherein the raw materials of the sludge solidifying agent include, by mass fraction, 25% of steelmaking solid waste, 22% of straw ash, 20% of phosphoric acid industrial solid waste, 20% of garbage combustion slag, 3% of composite reinforcing agent and 10% of solid carrier.

[0100] The mass ratio of the sludge solidifying agent to the sludge is 15%.

[0101] Example 4

[0102] Comparing Example 4 with Example 1, the difference between Example 4 and Example 1 is:

[0103] A solid waste-based sludge solidifying agent comprises, by mass fraction, raw materials of the sludge solidifying agent including: 30% of steelmaking solid waste, 22% of straw ash, 15% of phosphoric acid industrial solid waste, 20% of garbage combustion slag, 3% of composite reinforcing agent and 10 parts of solid carrier.

[0104] The mass ratio of the sludge solidifying agent to the sludge is 20%.

[0105] Example 5

[0106] Comparing Example 5 with Example 1, the difference between Example 5 and Example 1 is:

[0107] A solid waste-based sludge solidifying agent comprises, by mass fraction, raw materials of the sludge solidifying agent: 25% of steelmaking solid waste, 27% of straw ash, 15% of phosphoric acid industrial solid waste, 15% of garbage combustion slag, 3% of composite reinforcing agent and 15 parts of solid carrier.

[0108] The mass ratio of the sludge solidifying agent to the sludge is 15%.

[0109] Comparative Example 1

[0110] Comparative Example 1 and Example 1 are compared. The difference between Comparative Example 1 and Example 1 is:

[0111] Ordinary Portland cement is directly used as the sludge solidifying agent, and the mass ratio of the sludge solidifying agent to the sludge is 10%.

[0112] Comparative Example 2

[0113] Comparative Example 2 and Example 1 are compared. The difference between Comparative Example 2 and Example 1 is:

[0114] Ordinary Portland cement is directly used as the sludge solidifying agent, and the mass ratio of the sludge solidifying agent to the sludge is 15%.

[0115] Comparative Example 3

[0116] Comparative Example 3 and Example 1 are compared. The difference between Comparative Example 3 and Example 1 is:

[0117] Ordinary Portland cement is directly used as the sludge solidifying agent, and the mass ratio of the sludge solidifying agent to the sludge is 20%.

[0118] Related experiments and effect data:

[0119] The sludge and sludge solidifying agent mixed in each embodiment and comparative example were stirred evenly to obtain solidified sludge, and various performance tests were performed on the solidified sludge:

[0120] 1. Unconfined compressive strength test

[0121] The unconfined compressive strength of solidified sludge was measured using a microcomputer-controlled electronic universal testing machine (model WDW-100E) produced by Jinan Zhongzheng Testing Machine Manufacturing Co., Ltd. in accordance with the Highway Geotechnical Test Code (JTJ 051-1993). The results are shown in Table 1.

[0122] Table 1

[0123]

[0124] Specific analysis of Table 1: The unconfined compressive strength of each embodiment after curing for 7 days is greater than 1.5 MPa, which meets the requirements of the "Technical Specifications for Highway Pavement Base Construction" (JTJ 034-2000) for the compressive strength of road fill, while the unconfined compressive strength of the solidified sludge using ordinary Portland cement is less than 1 MPa, which does not meet the use requirements.

[0125] 2. Load ratio test

[0126] The solidified sludge of Examples 1-5 and Comparative Examples 1-3 was used as road filler for a bearing ratio test to test the bearing capacity of the material under unfavorable conditions. The CBR-I bearing ratio tester produced by Hebei Dahong Experimental Instrument Co., Ltd. was used to perform the test in accordance with Article T 0134-2019 of the Highway Geotechnical Test Code (JTG 3430-2020), and the results are shown in Table 2.

[0127]

[0128] Detailed analysis of Table 2: The bearing ratios of the solidified sludge in Examples 1-5 all meet the requirements of the "Technical Specifications for Highway Pavement Base Construction" (JTJ 034-2000) for the minimum roadbed strength CBR value to be greater than 8%, meeting the requirements for the use of road fillers. The sludge solidified with ordinary Portland cement cannot meet the requirements.

[0129] 3. Compression rebound modulus test

[0130] The solidified sludge of Examples 1-5 and Comparative Examples 1-3 was used as road filler for simulation test. The test was carried out using a microcomputer-controlled electronic universal testing machine (model WDW-100E) produced by Jinan Zhongzheng Testing Machine Manufacturing Co., Ltd. in accordance with T 0136-199 of the Highway Geotechnical Test Code (JTG 3430-2020). The results are shown in Table 3:

[0131] Table 3

[0132]

[0133]

[0134] Detailed analysis of Table 3: The "Highway Asphalt Pavement Design Specification" (JTG D50-2004) stipulates that the compressive resilience modulus of stabilized soil should be between 600MPa and 900MPa. It can be seen from Table 3 that the compressive resilience modulus of the sludge solidified by the curing agent of the present invention is relatively high, meeting the design requirements of the specification, while the compressive backfill modulus of the comparative example using ordinary Portland cement as the curing agent is relatively small and cannot meet the design specification requirements.

[0135] 2. Water resistance test

[0136] The solidified sludge of Examples 1-5 and Comparative Examples 1-3 was used as road filler for simulation test. A microcomputer-controlled electronic universal testing machine (model WDW-100E) produced by Jinan Zhongzheng Testing Machine Manufacturing Co., Ltd. was used. According to the provisions of T 0805-1994 in the "Testing Procedures for Inorganic Bonded Materials for Highway Engineering" (JTG E51-2009), the unconfined compressive strength of the simulated road filler under normal maintenance and immersion conditions was tested, and the strength loss rate was calculated. The test results are shown in Table 4.

[0137] Table 4

[0138] Group Strength loss rate (%) Example 1 10.6 Example 2 9.7 Example 3 9.1 Example 4 8.4 Example 5 10.1 Comparative Example 1 34.2 Comparative Example 2 30.1 Comparative Example 3 26.4

[0139] Specific analysis of Table 4: After being solidified by the solidifying agent provided by the present invention, the strength loss rate of the sludge after immersion in water is less than 15%, which meets the requirement that the softening coefficient of the water-resistant material is greater than 0.85, while the strength loss rate of the sludge solidified by ordinary Portland cement is greater than 25%, and the softening coefficient of the solidified sludge is less than 0.75, which is not suitable for direct use in water or in severely damp sites.

[0140] It can be seen from the data of Examples 1-5 that by using steelmaking solid waste, straw ash, phosphoric acid industrial solid waste, garbage combustion slag and composite reinforcing agent, the solidification strength of the sludge can be improved while the rebound modulus and CBR value of the sludge can be comprehensively improved and the strength loss after immersion in water can be reduced.

[0141] From the data of Comparative Examples 1-3, it can be seen that:

[0142] Although the strength of the solidified sludge obtained by using cement as a sludge solidifying agent cannot meet the requirements of the specification, the CBR value is lower than the requirements of the specification, the modulus of resilience is low, and the strength loss after immersion in water is large. Cement as a sludge solidifying agent will cause the sludge solidifying agent to cement, so that it cannot be reused. In addition, the production process of cement requires a lot of energy and produces a lot of greenhouse gases. Therefore, the use of cement in sludge solidifying agents should be reduced.

[0143] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0144] (1) A solid waste-based sludge solidifying agent provided in the embodiments of the present application is prepared by using steelmaking solid waste, straw ash, phosphoric acid industrial solid waste and garbage combustion slag. These materials have no obvious economic benefits when they exist alone and may even become a burden on the environment. However, after being crushed and ball-milled, they are mixed with a small amount of composite reinforcing agent in a certain proportion to form a solidifying agent for solidifying sludge. While solving the problem of environmental pollution caused by the accumulation of these wastes, a large amount of accumulated sludge can be treated, thus killing two birds with one stone.

[0145] (2) The solid waste-based sludge solidifying agent provided in the embodiments of the present application does not require the addition of cement or lime, and after solidification, the sludge will not form cement soil or alkaline soil to cause environmental damage.

[0146] (3) The method for preparing a solid waste-based sludge solidifying agent provided in the embodiments of the present application has the characteristics of energy-saving manufacturing, low cost, energy saving and being conducive to sustainable development.

[0147] (4) The application of a solid waste-based sludge solidifying agent provided in an embodiment of the present application, wherein the solidified sludge prepared therefrom has an unconfined compressive strength of not less than 1.5 MPa at 7 days of age, an unconfined compressive strength of not less than 1.8 MPa at 28 days of age, a CBR value of not less than 8%, a rebound modulus between 600 MPa and 900 MPa, and a strength loss after immersion in water of not more than 15%.

[0148] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0149] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A, and / or B, and / or C, which may represent the existence of any one of A, B, and C alone, or any one of them at the same time, or three of them at the same time. Wherein A, B, and C may be a single technical feature or a collection of multiple technical features. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "at least one of the following (individuals)" or similar expressions thereof refer to any combination of these items, including any combination of single (individuals) or plural (individuals). For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0150] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A solid waste-based sludge solidifying agent, characterized in that: The raw materials of the sludge solidifying agent include, by mass fraction: steelmaking solid waste: 40%, straw ash: 22%, phosphoric acid industry solid waste: 15%, garbage combustion slag: 15%, composite reinforcing agent: 3%, solid carrier: 5%; Wherein, the steelmaking solid waste includes steel slag; The chemical composition of the phosphoric acid industrial solid waste includes Ca; The composite reinforcing agent is used to enhance the curing strength of the sludge curing agent; The mass ratio of the steel slag to the steelmaking solid waste is ≥80%; The composite reinforcing agent comprises an oxidant, an early strength coagulant and a gelling agent, wherein the mass ratio of the oxidant, the early strength coagulant and the gelling agent is 1% to 3%: 1% to 3%: 1% to 3%; The oxidant comprises at least one of potassium permanganate, manganese dioxide and sodium peroxide; and / or The early strength accelerator comprises at least one of calcium chloride, sodium silicate and sodium carbonate; and / or The gelling agent comprises at least one of polyaluminium sulfate, sodium polyacrylate and methylcellulose; The solid carrier includes at least one of construction waste, fly ash and red mud.

2. A solid waste-based sludge solidifying agent, characterized in that: The raw materials of the sludge solidifying agent include, by mass fraction: steelmaking solid waste: 30%, straw ash: 22%, phosphoric acid industry solid waste: 15%, garbage combustion slag: 20%, composite reinforcing agent: 3%, solid carrier: 10%; Wherein, the steelmaking solid waste includes steel slag; The chemical composition of the phosphoric acid industrial solid waste includes Ca; The composite reinforcing agent is used to enhance the curing strength of the sludge curing agent; The mass ratio of the steel slag to the steelmaking solid waste is ≥80%; The composite reinforcing agent comprises an oxidant, an early strength coagulant and a gelling agent, wherein the mass ratio of the oxidant, the early strength coagulant and the gelling agent is 1% to 3%: 1% to 3%: 1% to 3%; The oxidant comprises at least one of potassium permanganate, manganese dioxide and sodium peroxide; and / or The early strength accelerator comprises at least one of calcium chloride, sodium silicate and sodium carbonate; and / or The gelling agent comprises at least one of polyaluminium sulfate, sodium polyacrylate and methylcellulose; The solid carrier includes at least one of construction waste, fly ash and red mud.

3. A solid waste-based sludge solidifying agent, characterized in that: The raw materials of the sludge solidifying agent include, by mass fraction: steelmaking solid waste: 25%, straw ash: 22%, phosphoric acid industry solid waste: 20%, garbage combustion slag: 20%, composite reinforcing agent: 3%, solid carrier: 10%; Wherein, the steelmaking solid waste includes steel slag; The chemical composition of the phosphoric acid industrial solid waste includes Ca; The composite reinforcing agent is used to enhance the curing strength of the sludge curing agent; The mass ratio of the steel slag to the steelmaking solid waste is ≥80%; The composite reinforcing agent comprises an oxidant, an early strength coagulant and a gelling agent, wherein the mass ratio of the oxidant, the early strength coagulant and the gelling agent is 1% to 3%: 1% to 3%: 1% to 3%; The oxidant comprises at least one of potassium permanganate, manganese dioxide and sodium peroxide; and / or The early strength accelerator comprises at least one of calcium chloride, sodium silicate and sodium carbonate; and / or The gelling agent comprises at least one of polyaluminium sulfate, sodium polyacrylate and methylcellulose; The solid carrier includes at least one of construction waste, fly ash and red mud.

4. The sludge solidifying agent according to any one of claims 1 to 3, characterized in that: The phosphoric acid industrial solid waste includes phosphogypsum, and the mass ratio of the phosphogypsum to the phosphoric acid industrial solid waste is ≥90%.

5. The sludge solidifying agent according to any one of claims 1 to 3, characterized in that: The mass fraction of the solid carrier to the total weight of the sludge solidifying agent is 5% to 15%.

6. A method for preparing the solid waste-based sludge solidifying agent according to any one of claims 1 to 5, characterized in that: The method comprises: The steelmaking solid waste, the garbage combustion slag and the solid carrier are respectively subjected to a first screening, and then subjected to a second screening to obtain a steelmaking solid waste undersize, a garbage combustion slag undersize and a solid carrier undersize; alkalinizing the phosphoric acid industrial solid waste to obtain alkalinized solid waste; The straw ash and the alkalized solid waste are dried respectively, and then the second screening is performed to obtain straw ash undersize and alkalized solid waste undersize; The steelmaking solid waste undersize, the garbage combustion slag undersize, the solid carrier undersize, the straw ash undersize, the alkalized solid waste undersize and the composite reinforcing agent are mixed to obtain a sludge solidifying agent.

7. The method according to claim 6, characterized in that The mesh size of the first sieve is 1 mm to 3 mm, and the mesh size of the second sieve is 0.1 mm to 0.2 mm.

8. An application of a solid waste-based sludge solidifying agent, characterized in that: The application comprises using the solid waste-based sludge solidifying agent according to any one of claims 1 to 5 in the solidification stage of preparing fill material from sludge, wherein the mass ratio of the sludge solidifying agent to the sludge is 10% to 20%.

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