Sludge curing agent synergistically excited by multi-source industrial solid waste

Abstract

The invention relates to the technical field of sludge curing agents, in particular to a sludge curing agent synergistically excited by utilizing multi-source industrial solid waste, which comprises the following components: modified multi-source industrial solid waste, a synergistic exciting agent, an auxiliary curing agent and a modifier, according to the invention, the modified multi-source industrial solid waste, the synergistic activator, the auxiliary curing agent and the modifier are combined according to a scientific ratio, and through a preparation process of step-by-step stirring and mixing, all the components are ensured to be uniformly dispersed and fully contacted. On the whole, the modified multi-source industrial solid waste serves as a core base material, and sufficient active ingredients and framework support are provided; the reaction process is accurately regulated and controlled by the synergistic excitant, and the activity of the substrate is maximally excited; the auxiliary curing agent and the modifier are supplemented and improved from the aspects of structure filling, interface optimization, performance strengthening and the like. According to the technical scheme of multi-component cooperation, high-value utilization of multi-source industrial solid waste is achieved, and environmental pressure caused by industrial solid waste stacking and traditional curing agent production is reduced.

Description

Technical Field

[0001] This invention relates to the field of sludge solidification agent technology, specifically a sludge solidification agent that utilizes the synergistic activation of multi-source industrial solid waste. Background Technology

[0002] With the acceleration of urbanization and the continuous development of industrial production, the amount of silt generated by river dredging, engineering construction, and other activities has increased significantly. This silt typically contains large amounts of water, organic matter, heavy metals, and various pollutants. If directly dumped or indiscriminately discharged, it will not only occupy a large amount of land resources but may also cause a series of environmental problems such as soil pollution and groundwater pollution, seriously threatening ecological security and human health. Therefore, the harmless treatment and resource utilization of silt has become an important issue that urgently needs to be addressed in the field of environmental protection.

[0003] Currently, sludge solidification technology is widely used in sludge treatment projects due to its advantages such as simple operation, high processing efficiency, and relatively low cost. This technology involves adding a solidifying agent to the sludge, utilizing the physicochemical reaction between the solidifying agent and sludge particles to improve the sludge's physical and mechanical properties, reduce its moisture content and pollutant mobility, enabling the solidified sludge to meet the requirements of engineering applications such as backfilling and foundation treatment. However, existing sludge solidifying agents still have many shortcomings: on the one hand, traditional solidifying agents mostly use cement, lime, etc., as their main raw materials, which not only consumes a large amount of non-renewable resources but also generates a lot of carbon emissions during production, which is inconsistent with the concept of green development; on the other hand, some solidifying agents have problems such as low solidification efficiency, poor mechanical properties of the solidified body, and insufficient water stability and durability, making it difficult to adapt to complex engineering environments and long-term use requirements.

[0004] Therefore, developing a sludge solidifying agent that can achieve efficient resource utilization of multi-source industrial solid waste, and has excellent solidification effect and is environmentally friendly, has important practical significance and application value. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and propose a sludge solidification agent that utilizes the synergistic activation of multi-source industrial solid waste.

[0006] The specific technical solution is as follows: A sludge solidifying agent that utilizes the synergistic activation of multi-source industrial solid waste, characterized in that it comprises the following components: 50-80 parts of modified multi-source industrial solid waste, 5-15 parts of synergistic activator, 3-10 parts of auxiliary solidifying agent, and 1-5 parts of modifier.

[0007] The modified multi-source industrial solid waste is a mixture of slag, steel slag, and carbide slag that have undergone mechanical-chemical-high temperature gradient combined modification treatment, with a mass ratio of (3-5):(2-4):(1-3).

[0008] The synergistic activator is a ternary composite system consisting of an alkali activating component, a sulfate activating component, and a composite retarding activating component, with a mass ratio of (60-75):(15-25):(5-10).

[0009] The auxiliary curing agent is a mixture of metakaolin, zeolite powder, and sodium lignosulfonate, with a mass ratio of (4-6):(2-3):(1-2).

[0010] The modifier is a ternary mixture of modified bentonite, aminotrimethylene phosphonic acid and graphene quantum dots, with a mass ratio of (6-8):(2-3):1.

[0011] As a further technical solution, the method for preparing the modified multi-source industrial solid waste includes the following steps:

[0012] S1. Pretreatment: The slag, steel slag, and carbide slag are crushed and screened to a particle size ≤100μm. After removing impurities, they are placed in an oven at 105-110℃ and dried to constant weight to obtain pretreated industrial solid waste.

[0013] S2. Mechanical activation modification: The pretreated slag, steel slag and carbide slag are mixed in proportion and added to a ball mill. The ball-to-material ratio is controlled at (10-15):1, the rotation speed is 200-300 r / min, and the activation time is 60-80 min to obtain a mechanically activated mixture.

[0014] S3. Chemical modification: Add an alkaline modified aqueous solution to the mechanically activated mixture at a mass ratio of 1:1, and react in a constant temperature water bath at 60-80℃ for 30-60 minutes, stirring once every 10-15 minutes during the reaction. After the reaction is completed, filter and dry to obtain the primary modified mixture.

[0015] S4. High-temperature activation modification: The primary modified mixture is placed in a muffle furnace and heated to 300-400℃ for 30 min at a heating rate of 5-10℃ / min. Then, it is heated to 600-700℃ for 60-90 min. After cooling to room temperature, it is crushed and sieved to a particle size ≤80μm to obtain modified multi-source industrial solid waste.

[0016] As a further technical solution, the alkaline modified aqueous solution has a pH of 10-12 and is a mixed aqueous solution of sodium hydroxide and water glass.

[0017] As a further technical solution, the alkaline activating component is a mixture of sodium hydroxide and water glass, with a mass ratio of 1:(1.5-2.5); the sulfate activating component is a mixture of anhydrous sodium sulfate and aluminum sulfate, with a mass ratio of (3-5):1; and the composite retarding activating component is a mixture of citric acid and boric acid, with a mass ratio of (1-2):1.

[0018] As a further technical solution, the molecular weight of sodium lignosulfonate in the auxiliary curing agent is 8000-15000.

[0019] As a further technical solution, the modified bentonite is sodium-based bentonite modified with hexadecyltrimethylammonium bromide.

[0020] As a further technical solution, the modified bentonite is prepared by: crushing and sieving sodium-based bentonite to a particle size ≤50μm, adding a 2-5% (w / w) aqueous solution of hexadecyltrimethylammonium bromide, with a solid-liquid ratio of 1:(5-8), stirring and reacting at 60-70℃ for 2-3 hours, and then filtering, drying, and crushing to obtain modified bentonite.

[0021] As a further technical solution, the particle size of the graphene quantum dots is 5-20 nm.

[0022] As a further technical solution, the preparation method of the sludge solidification agent includes the following steps:

[0023] Step 1: Weigh each component according to the formula and set aside. Control the preparation environment temperature at 20-25℃ and the relative humidity at 40-60%.

[0024] Step 2: Add the modified multi-source industrial solid waste and modifier into a mixer and stir at a speed of 150-200 r / min for 15-20 min to obtain mixture A;

[0025] Step 3: Add the synergist to mixture A, adjust the stirring speed to 250-300 r / min, and stir for 20-30 min to obtain mixture B;

[0026] Step 4: Add auxiliary curing agent to mixture B, adjust the stirring speed to 180-220 r / min, continue stirring for 10-15 min, after mixing evenly, crush and sieve to a particle size ≤60μm to obtain the sludge curing agent.

[0027] As a further technical solution, the amount of the sludge solidifying agent added to the sludge is 8-15% of the dry weight of the sludge.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention employs a combined mechanical-chemical-high-temperature gradient modification process to treat a mixture of slag, steel slag, and carbide slag, forming modified multi-source industrial solid waste. Mechanical activation, through ball milling at a high ball-to-material ratio and appropriate rotation speed, breaks down the agglomeration structure of the industrial solid waste particles, increasing the specific surface area and exposing more active sites. Chemical modification utilizes the corrosive effect of alkaline aqueous solution to dissolve the inert layer on the particle surface, activating potential internal active components. High-temperature activation, through gradient heating and heat preservation, promotes the reconstruction of the internal crystal structure of the particles, further enhancing reactivity. Due to this multi-step combined modification process, the activity of the industrial solid waste is fully activated. As a major component of the solidifying agent, it can undergo hydration and gelation reactions with water and ions in the sludge, generating a large amount of hydrated calcium silicate, hydrated calcium aluminate, and other gelling products. These products can fill the gaps between sludge particles, binding the loose sludge particles into a whole, thereby significantly improving the density and mechanical strength of the solidified body. This solves the problem of low activity and insufficient utilization rate of traditional industrial solid waste in solidifying agents, leading to poor solidification effects.

[0030] The synergistic activator of this invention employs a ternary composite system of an alkali-activating component, a sulfate-activating component, and a composite retarding activating component. The alkali-activating component further promotes the dissolution of active silicon and aluminum components in modified multi-source industrial solid waste, accelerating the gelation reaction process; the sulfate-activating component reacts with hydration products to generate high-strength ettringite, enhancing the early strength of the solidified body; the composite retarding activating component effectively regulates the reaction rate, preventing excessively rapid reactions that could lead to stress cracks within the solidified body, ensuring a stable solidification process. Due to the synergistic effect of the three components, both efficient activation of the activity of modified industrial solid waste and controllability of the solidification reaction are achieved, resulting in a solidified body with a uniform structure and stable strength. Simultaneously, metakaolin and zeolite powder in the auxiliary solidifying agent play a filling and volcanic ash-like active role, while sodium lignosulfonate improves material dispersibility and the structure of hydration products; modified bentonite in the modifier enhances adsorption and ion exchange capacity, aminotrimethylenephosphonic acid optimizes interfacial bonding performance, and graphene quantum dots improve the density and durability of the solidified body through nano-effects.

[0031] This invention combines modified multi-source industrial solid waste, synergistic activators, auxiliary curing agents, and modifiers in a scientifically proportioned formula. A step-by-step mixing process ensures uniform dispersion and full contact of each component. Overall, the modified multi-source industrial solid waste serves as the core substrate, providing ample active ingredients and skeletal support. The synergistic activator precisely controls the reaction process, maximizing the activity of the substrate. The auxiliary curing agent and modifier supplement and enhance the substrate in terms of structural filling, interface optimization, and performance enhancement. This multi-component synergistic technical solution not only achieves high-value utilization of multi-source industrial solid waste, reducing the environmental pressure from industrial solid waste stockpiling and traditional curing agent production, aligning with the concept of green and low-carbon development, but also enables efficient solidification of sludge at relatively low dosages through the synergistic effect of the components. The mechanical properties, water stability, and durability of the solidified body all meet engineering application requirements. Meanwhile, the preparation process is simple and easy to implement, the conditions are mild, it is suitable for large-scale industrial production, the construction is convenient and the cost is controllable, thus solving the problems of high resource consumption, poor environmental performance, insufficient comprehensive performance and high application cost of existing sludge solidification agents. It provides an efficient, environmentally friendly and economical solution for the harmless treatment and resource utilization of sludge, and has significant environmental, economic and social benefits. Attached Figure Description

[0032] Figure 1 This is a flowchart of the preparation method for modified multi-source industrial solid waste. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] This invention provides a sludge solidifying agent that utilizes the synergistic activation of multi-source industrial solid waste, comprising, by weight, 50-80 parts of modified multi-source industrial solid waste, 5-15 parts of synergistic activator, 3-10 parts of auxiliary solidifying agent, and 1-5 parts of modifier.

[0035] In this invention, the modified multi-source industrial solid waste is a mixture of slag, steel slag, and carbide slag that have undergone mechanical-chemical-high temperature gradient combined modification treatment, with a mass ratio of 3-5:2-4:1-3, preferably 4:3:2.

[0036] The method for preparing the modified multi-source industrial solid waste includes the following steps:

[0037] S1. Pretreatment: The slag, steel slag, and carbide slag are crushed and screened to a particle size ≤100μm. After removing impurities, they are placed in an oven at 105-110℃ and dried to constant weight to obtain pretreated industrial solid waste.

[0038] S2. Mechanical activation modification: The pretreated slag, steel slag and carbide slag are mixed in proportion and added to a ball mill. The ball-to-material ratio is controlled at 10-15:1, the rotation speed is 200-300 r / min, and the activation time is 60-80 min to obtain a mechanically activated mixture.

[0039] S3. Chemical modification: Add an alkaline modified aqueous solution to the mechanically activated mixture at a mass ratio of 1:1, and react in a constant temperature water bath at 60-80℃ for 30-60 minutes, stirring once every 10-15 minutes during the reaction. After the reaction is completed, filter and dry to obtain the primary modified mixture.

[0040] S4. High-temperature activation modification: The primary modified mixture is placed in a muffle furnace and heated to 300-400℃ for 30 min at a heating rate of 5-10℃ / min. Then, it is heated to 600-700℃ for 60-90 min. After cooling to room temperature, it is crushed and sieved to a particle size ≤80μm to obtain modified multi-source industrial solid waste.

[0041] The alkaline modified aqueous solution with a pH of 10-12 is a mixed aqueous solution of sodium hydroxide and water glass. The present invention does not impose any special restrictions on the specific ratio of sodium hydroxide and water glass, and conventional ratios in the field can be used.

[0042] In this invention, the synergistic activator is a ternary composite system of an alkali activating component, a sulfate activating component, and a composite retarding activating component, with a mass ratio of 60-75:15-25:5-10, preferably 68:20:7.

[0043] The alkaline activating component is a mixture of sodium hydroxide and water glass, with a mass ratio of 1:1.5-2.5, preferably 1:2; the sulfate activating component is a mixture of anhydrous sodium sulfate and aluminum sulfate, with a mass ratio of 3-5:1, preferably 4:1; the composite retarding activating component is a mixture of citric acid and boric acid, with a mass ratio of 1-2:1, preferably 1.5:1.

[0044] In this invention, the auxiliary curing agent is a mixture of metakaolin, zeolite powder, and sodium lignosulfonate, with a mass ratio of 4-6:2-3:1-2, preferably 5:2.5:1.5; wherein the molecular weight of sodium lignosulfonate is 8000-15000.

[0045] In this invention, the modifier is a ternary mixture of modified bentonite, aminotrimethylenephosphonic acid and graphene quantum dots, with a mass ratio of 6-8:2-3:1, preferably 7:2.5:1.

[0046] The modified bentonite is sodium-based bentonite modified with hexadecyltrimethylammonium bromide. The preparation method is as follows: sodium-based bentonite is crushed and sieved to a particle size ≤50μm, and a hexadecyltrimethylammonium bromide aqueous solution with a mass concentration of 2-5% is added. The solid-liquid ratio is 1:5-8, and the mixture is stirred and reacted at 60-70℃ for 2-3 hours. After filtration, drying, and crushing, the modified bentonite is obtained.

[0047] The graphene quantum dots have a particle size of 5-20 nm. The present invention does not have any special restrictions on their source and can use commercially available products known to those skilled in the art.

[0048] The method for preparing the sludge solidifying agent provided by the present invention includes the following steps:

[0049] Step 1: Weigh each component according to the formula and set aside. Control the preparation environment temperature at 20-25℃ and the relative humidity at 40-60%.

[0050] Step 2: Add the modified multi-source industrial solid waste and modifier into a mixer and stir at a speed of 150-200 r / min for 15-20 min to obtain mixture A;

[0051] Step 3: Add the synergist to mixture A, adjust the stirring speed to 250-300 r / min, and stir for 20-30 min to obtain mixture B;

[0052] Step 4: Add auxiliary curing agent to mixture B, adjust the stirring speed to 180-220 r / min, continue stirring for 10-15 min, after mixing evenly, crush and sieve to a particle size ≤60μm to obtain the sludge curing agent.

[0053] The sludge solidifying agent provided by this invention is added at an amount of 8-15% of the dry weight of the sludge.

[0054] To further illustrate the present invention, the following detailed description is provided through the examples and comparative examples.

[0055] In the following embodiments and comparative examples of this invention: the slag, steel slag, and carbide slag used are all solid wastes generated in industrial production and are used after conventional pretreatment; sodium hydroxide, water glass, anhydrous sodium sulfate, aluminum sulfate, citric acid, boric acid, metakaolin, zeolite powder, sodium lignosulfonate (molecular weight 10000), sodium bentonite, hexadecyltrimethylammonium bromide, and aminotrimethylenephosphonic acid are all commercially available analytical grade reagents; graphene quantum dots (particle size 10 nm) are commercially available.

[0056] Example 1:

[0057] 1. Preparation of modified multi-source industrial solid waste:

[0058] S1. Pretreatment: The slag, steel slag, and calcium carbide slag are crushed and sieved to a particle size ≤100μm, and impurities are removed. They are then dried in an oven at 105℃ to constant weight to obtain pretreated industrial solid waste.

[0059] S2. Mechanical activation modification: Weigh the pretreated slag, steel slag and carbide slag at a mass ratio of 3:2:1, mix them evenly and add them to a ball mill. Control the ball-to-material ratio to be 10:1, the rotation speed to be 200 r / min, and activate for 60 min to obtain a mechanically activated mixture.

[0060] S3. Chemical modification: Add an alkaline modified aqueous solution with pH=10 to the mechanically activated mixture at a mass ratio of 1:1. React in a constant temperature water bath at 60℃ for 30 min, stirring once every 10 min during the reaction. After the reaction is completed, filter and dry to obtain the primary modified mixture.

[0061] S4. High-temperature activation modification: The primary modified mixture is placed in a muffle furnace and heated to 300℃ for 30 min at a heating rate of 5℃ / min. Then it is heated to 600℃ for 60 min. After cooling to room temperature, it is crushed and sieved to a particle size ≤80μm to obtain modified multi-source industrial solid waste.

[0062] 2. Preparation of modified bentonite:

[0063] Sodium-based bentonite was pulverized and sieved to a particle size ≤50μm, and then a 2% (w / w) aqueous solution of hexadecyltrimethylammonium bromide was added at a solid-liquid ratio of 1:5. The mixture was stirred at 60℃ for 2 hours, filtered, dried, and pulverized to obtain modified bentonite.

[0064] 3. Preparation of synergistic activators:

[0065] Sodium hydroxide and water glass were weighed in a mass ratio of 1:1.5 and mixed evenly to obtain an alkali-activating component; anhydrous sodium sulfate and aluminum sulfate were weighed in a mass ratio of 3:1 and mixed evenly to obtain a sulfate-activating component; citric acid and boric acid were weighed in a mass ratio of 1:1 and mixed evenly to obtain a composite retarding activating component; then, the alkali-activating component, sulfate-activating component, and composite retarding activating component were weighed in a mass ratio of 60:15:5 and mixed evenly to obtain a synergistic activator.

[0066] 4. Preparation of auxiliary curing agent:

[0067] Weigh out metakaolin, zeolite powder, and sodium lignosulfonate in a mass ratio of 4:2:1, and mix them evenly to obtain the auxiliary curing agent.

[0068] 5. Preparation of the modifier:

[0069] Weigh the modified bentonite, aminotrimethylene phosphonic acid and graphene quantum dots prepared above in a mass ratio of 6:2:1, and mix them evenly to obtain the modifier.

[0070] 6. Preparation of sludge solidification agent:

[0071] Step 1: Weigh out 50 parts by weight of modified multi-source industrial solid waste, 5 parts by weight of synergistic activator, 3 parts by weight of auxiliary curing agent, and 1 part by weight for later use. Control the preparation environment temperature at 20℃ and the relative humidity at 40%.

[0072] Step 2: Add the modified multi-source industrial solid waste and the modifier into a mixer and stir at 150 r / min for 15 min to obtain mixture A;

[0073] Step 3: Add the synergist to mixture A, adjust the stirring speed to 250 r / min, stir for 20 min, and obtain mixture B;

[0074] Step 4: Add auxiliary curing agent to mixture B, adjust the stirring speed to 180 r / min, continue stirring for 10 min, and after mixing evenly, crush and sieve until the particle size is ≤60μm to obtain sludge curing agent.

[0075] 7. Sludge solidification treatment:

[0076] Take some river silt and measure its dry density to be 1.2 g / cm³ and water content to be 65%. Add the prepared silt solidifying agent to the silt at 8% of the dry mass of the silt. After stirring evenly, put it into a mold and cure it under standard curing conditions (temperature 20±2℃, relative humidity ≥95%) until the specified age, and then conduct performance tests.

[0077] Example 2:

[0078] 1. Preparation of modified multi-source industrial solid waste:

[0079] S1. Pretreatment: The slag, steel slag, and carbide slag are crushed and screened to a particle size ≤100μm. After removing impurities, they are placed in an oven at 110℃ and dried to constant weight to obtain pretreated industrial solid waste.

[0080] S2. Mechanical activation modification: Weigh the pretreated slag, steel slag and carbide slag at a mass ratio of 5:4:3, mix them evenly and add them to a ball mill. Control the ball-to-material ratio to be 15:1, the rotation speed to be 300 r / min, and activate for 80 min to obtain a mechanically activated mixture.

[0081] S3. Chemical modification: Add an alkaline modified aqueous solution with pH=12 to the mechanically activated mixture at a mass ratio of 1:1. React in a constant temperature water bath at 80℃ for 60 min, stirring once every 15 min during the reaction. After the reaction is completed, filter and dry to obtain the primary modified mixture.

[0082] S4. High-temperature activation modification: The primary modified mixture is placed in a muffle furnace and heated to 400℃ for 30 min at a heating rate of 10℃ / min. Then it is heated to 700℃ for 90 min. After cooling to room temperature, it is crushed and sieved to a particle size ≤80μm to obtain modified multi-source industrial solid waste.

[0083] 2. Preparation of modified bentonite:

[0084] Sodium-based bentonite was pulverized and sieved to a particle size ≤50μm, and then a 5% (w / w) aqueous solution of hexadecyltrimethylammonium bromide was added at a solid-liquid ratio of 1:8. The mixture was stirred at 70℃ for 3 hours, filtered, dried, and pulverized to obtain modified bentonite.

[0085] 3. Preparation of synergistic activators:

[0086] Sodium hydroxide and water glass were weighed in a mass ratio of 1:2.5 and mixed evenly to obtain an alkali-activating component; anhydrous sodium sulfate and aluminum sulfate were weighed in a mass ratio of 5:1 and mixed evenly to obtain a sulfate-activating component; citric acid and boric acid were weighed in a mass ratio of 2:1 and mixed evenly to obtain a composite retarding activating component; then, the alkali-activating component, sulfate-activating component, and composite retarding activating component were weighed in a mass ratio of 75:25:10 and mixed evenly to obtain a synergistic activator.

[0087] 4. Preparation of auxiliary curing agent:

[0088] Weigh out metakaolin, zeolite powder, and sodium lignosulfonate in a mass ratio of 6:3:2, and mix them evenly to obtain the auxiliary curing agent.

[0089] 5. Preparation of the modifier:

[0090] Weigh the modified bentonite, aminotrimethylene phosphonic acid and graphene quantum dots prepared above in a mass ratio of 8:3:1, and mix them evenly to obtain the modifier.

[0091] 6. Preparation of sludge solidification agent:

[0092] Step 1: Weigh out 80 parts by weight of modified multi-source industrial solid waste, 15 parts by weight of synergistic activator, 10 parts by weight of auxiliary solidifying agent, and 5 parts by weight for later use. Control the preparation environment temperature at 25℃ and the relative humidity at 60%.

[0093] Step 2: Add the modified multi-source industrial solid waste and the modifier into a mixer and stir at 200 r / min for 20 min to obtain mixture A;

[0094] Step 3: Add the synergist to mixture A, adjust the stirring speed to 300 r / min, stir for 30 min, and obtain mixture B;

[0095] Step 4: Add auxiliary curing agent to mixture B, adjust the stirring speed to 220 r / min, continue stirring for 15 min, and after mixing evenly, crush and sieve to a particle size ≤60μm to obtain sludge curing agent.

[0096] 7. Sludge solidification treatment:

[0097] Take the same river silt as in Example 1, add 15% of the dry weight of the silt to the silt solidifying agent prepared above, stir evenly, put it into a mold, and cure it under standard curing conditions (temperature 20±2℃, relative humidity ≥95%) until the specified age, and then conduct performance tests.

[0098] Example 3:

[0099] 1. Preparation of modified multi-source industrial solid waste:

[0100] S1. Pretreatment: The slag, steel slag, and carbide slag are crushed and screened to a particle size ≤100μm. After removing impurities, they are placed in an oven at 108℃ and dried to constant weight to obtain pretreated industrial solid waste.

[0101] S2. Mechanical activation modification: Weigh the pretreated slag, steel slag and carbide slag in a mass ratio of 4:3:2, mix them evenly and add them to a ball mill. Control the ball-to-material ratio to be 12:1, the rotation speed to be 250 r / min, and activate for 70 min to obtain a mechanically activated mixture.

[0102] S3. Chemical modification: Add an alkaline modified aqueous solution with pH=11 to the mechanically activated mixture at a mass ratio of 1:1. React in a constant temperature water bath at 70℃ for 45 min, stirring once every 12 min during the reaction. After the reaction is completed, filter and dry to obtain the primary modified mixture.

[0103] S4. High-temperature activation modification: The primary modified mixture is placed in a muffle furnace and heated to 350℃ for 30 min at a heating rate of 8℃ / min. Then it is heated to 650℃ for 75 min. After cooling to room temperature, it is crushed and sieved to a particle size ≤80μm to obtain modified multi-source industrial solid waste.

[0104] 2. Preparation of modified bentonite:

[0105] Sodium-based bentonite was pulverized and sieved to a particle size ≤50μm, and then a 3% (w / w) aqueous solution of hexadecyltrimethylammonium bromide was added at a solid-liquid ratio of 1:6. The mixture was stirred at 65℃ for 2.5h, filtered, dried, and pulverized to obtain modified bentonite.

[0106] 3. Preparation of synergistic activators:

[0107] Sodium hydroxide and water glass were weighed in a mass ratio of 1:2 and mixed evenly to obtain an alkali-activating component; anhydrous sodium sulfate and aluminum sulfate were weighed in a mass ratio of 4:1 and mixed evenly to obtain a sulfate-activating component; citric acid and boric acid were weighed in a mass ratio of 1.5:1 and mixed evenly to obtain a composite retarding activating component; then, the alkali-activating component, sulfate-activating component, and composite retarding activating component were weighed in a mass ratio of 68:20:7 and mixed evenly to obtain a synergistic activator.

[0108] 4. Preparation of auxiliary curing agent:

[0109] Weigh out metakaolin, zeolite powder, and sodium lignosulfonate in a mass ratio of 5:2.5:1.5, and mix them evenly to obtain the auxiliary curing agent.

[0110] 5. Preparation of the modifier:

[0111] Weigh the modified bentonite, aminotrimethylene phosphonic acid and graphene quantum dots prepared above in a mass ratio of 7:2.5:1, and mix them evenly to obtain the modifier.

[0112] 6. Preparation of sludge solidification agent:

[0113] Step 1: Weigh out 65 parts by weight of modified multi-source industrial solid waste, 10 parts by weight of synergistic activator, 6 parts by weight of auxiliary solidifying agent, and 3 parts by weight for later use. Control the preparation environment temperature at 22℃ and the relative humidity at 50%.

[0114] Step 2: Add the modified multi-source industrial solid waste and the modifier into a mixer and stir at 180 r / min for 18 min to obtain mixture A;

[0115] Step 3: Add the synergist to mixture A, adjust the stirring speed to 280 r / min, stir for 25 min, and obtain mixture B;

[0116] Step 4: Add auxiliary curing agent to mixture B, adjust the stirring speed to 200 r / min, continue stirring for 12 min, and after mixing evenly, crush and sieve until the particle size is ≤60μm to obtain sludge curing agent.

[0117] 7. Sludge solidification treatment:

[0118] Take the same river silt as in Example 1, add 12% of the dry weight of the silt to the silt solidifying agent prepared above, stir evenly, put it into a mold, and cure it under standard curing conditions (temperature 20±2℃, relative humidity ≥95%) until the specified age, and then conduct performance tests.

[0119] Comparative Example 1:

[0120] 1. Preparation of modified multi-source industrial solid waste:

[0121] The preparation method is exactly the same as that of modified multi-source industrial solid waste in Example 3.

[0122] 2. Preparation of modified bentonite:

[0123] The preparation method is exactly the same as that of the modified bentonite in Example 3.

[0124] 3. Preparation of auxiliary curing agent:

[0125] The preparation method of the auxiliary curing agent is exactly the same as that in Example 3.

[0126] 4. Preparation of the modifier:

[0127] The preparation method of the modifier is exactly the same as that in Example 3.

[0128] 5. Preparation of sludge solidification agent:

[0129] Step 1: Weigh out 65 parts by weight of modified multi-source industrial solid waste, 6 parts by weight of auxiliary solidifying agent, and 3 parts by weight for later use. Control the preparation environment temperature at 22℃ and the relative humidity at 50%.

[0130] Step 2: Add the modified multi-source industrial solid waste and the modifier into a mixer and stir at 180 r / min for 18 min to obtain mixture A;

[0131] Step 3: Add auxiliary curing agent to mixture A, adjust the stirring speed to 200 r / min, continue stirring for 12 min, and after mixing evenly, crush and sieve until the particle size is ≤60μm to obtain sludge curing agent.

[0132] 6. Sludge solidification treatment:

[0133] Take the same river silt as in Example 1, add 12% of the dry weight of the silt to the silt solidifying agent prepared above, stir evenly, put it into a mold, and cure it under standard curing conditions (temperature 20±2℃, relative humidity ≥95%) until the specified age, and then conduct performance tests.

[0134] Comparative Example 2:

[0135] 1. Preparation of unmodified multi-source industrial solid waste:

[0136] Slag, steel slag, and carbide slag were weighed in a mass ratio of 4:3:2, crushed and screened to a particle size ≤80μm, and after removing impurities, they were mixed evenly to obtain unmodified multi-source industrial solid waste.

[0137] 2. Preparation of modified bentonite:

[0138] The preparation method is exactly the same as that of the modified bentonite in Example 3.

[0139] 3. Preparation of synergistic activators:

[0140] The preparation method is exactly the same as that of the synergist in Example 3.

[0141] 4. Preparation of auxiliary curing agent:

[0142] The preparation method of the auxiliary curing agent is exactly the same as that in Example 3.

[0143] 5. Preparation of the modifier:

[0144] The preparation method of the modifier is exactly the same as that in Example 3.

[0145] 6. Preparation of sludge solidification agent:

[0146] Step 1: Weigh out 65 parts by weight of unmodified multi-source industrial solid waste, 10 parts by weight of synergistic activator, 6 parts by weight of auxiliary solidifying agent, and 3 parts by weight of modifier for later use. Control the preparation environment temperature at 22℃ and the relative humidity at 50%.

[0147] Step 2: Add the unmodified multi-source industrial solid waste and modifier into a mixer and stir at 180 r / min for 18 min to obtain mixture A;

[0148] Step 3: Add the synergist to mixture A, adjust the stirring speed to 280 r / min, stir for 25 min, and obtain mixture B;

[0149] Step 4: Add auxiliary curing agent to mixture B, adjust the stirring speed to 200 r / min, continue stirring for 12 min, and after mixing evenly, crush and sieve until the particle size is ≤60μm to obtain sludge curing agent.

[0150] 7. Sludge solidification treatment:

[0151] Take the same river silt as in Example 1, add 12% of the dry weight of the silt to the silt solidifying agent prepared above, stir evenly, put it into a mold, and cure it under standard curing conditions (temperature 20±2℃, relative humidity ≥95%) until the specified age, and then conduct performance tests.

[0152] Experiment: Mechanical property testing of solidified sludge:

[0153] Unconfined compressive strength and shear strength (cohesion and internal friction angle) tests were conducted on the solidified sludge after 7 and 28 days of curing. Unconfined compressive strength testing was performed using a strain-controlled unconfined compressive strength tester with a loading rate of 1 mm / min. Shear strength testing was performed using a direct shear tester with vertical pressures of 100 kPa, 200 kPa, 300 kPa, and 400 kPa, and a shear rate of 0.8 mm / min. Three parallel samples were tested for each sample, and the average value was taken as the test result. The results are as follows:

[0154] Table 1

[0155]

[0156] The experimental results show that the sludge treated with the sludge solidification agents prepared in Examples 1-3 exhibited good mechanical properties at 7d and 28d ages, with unconfined compressive strength, cohesion and internal friction angle significantly higher than those of Comparative Example 1 and Comparative Example 2.

[0157] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not describe all details exhaustively, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification.

Claims

1. A sludge solidification agent utilizing the synergistic activation of multi-source industrial solid waste, characterized in that, By weight, it includes the following components: 50-80 parts of modified multi-source industrial solid waste, 5-15 parts of synergistic activator, 3-10 parts of auxiliary curing agent, and 1-5 parts of modifier. The modified multi-source industrial solid waste is a mixture of slag, steel slag, and carbide slag that have undergone mechanical-chemical-high temperature gradient combined modification treatment, with a mass ratio of (3-5):(2-4):(1-3). The synergistic activator is a ternary composite system consisting of an alkali activating component, a sulfate activating component, and a composite retarding activating component, with a mass ratio of (60-75):(15-25):(5-10). The auxiliary curing agent is a mixture of metakaolin, zeolite powder, and sodium lignosulfonate, with a mass ratio of (4-6):(2-3):(1-2). The modifier is a ternary mixture of modified bentonite, aminotrimethylene phosphonic acid and graphene quantum dots, with a mass ratio of (6-8):(2-3):

1.

2. The sludge solidifying agent according to claim 1, characterized in that, The method for preparing the modified multi-source industrial solid waste includes the following steps: S1. Pretreatment: The slag, steel slag, and carbide slag are crushed and screened to a particle size ≤100μm. After removing impurities, they are placed in an oven at 105-110℃ and dried to constant weight to obtain pretreated industrial solid waste. S2. Mechanical activation modification: The pretreated slag, steel slag and carbide slag are mixed in proportion and added to a ball mill. The ball-to-material ratio is controlled at (10-15):1, the rotation speed is 200-300 r / min, and the activation time is 60-80 min to obtain a mechanically activated mixture. S3. Chemical modification: Add an alkaline modified aqueous solution to the mechanically activated mixture at a mass ratio of 1:1, and react in a constant temperature water bath at 60-80℃ for 30-60 minutes, stirring once every 10-15 minutes during the reaction. After the reaction is completed, filter and dry to obtain the primary modified mixture. S4. High-temperature activation modification: The primary modified mixture is placed in a muffle furnace and heated to 300-400℃ for 30 min at a heating rate of 5-10℃ / min. Then, it is heated to 600-700℃ for 60-90 min. After cooling to room temperature, it is crushed and sieved to a particle size ≤80μm to obtain modified multi-source industrial solid waste.

3. The sludge solidifying agent according to claim 2, characterized in that, The alkaline modified aqueous solution has a pH of 10-12 and is a mixed aqueous solution of sodium hydroxide and water glass.

4. The sludge solidifying agent according to claim 1, characterized in that, The alkaline activating component is a mixture of sodium hydroxide and water glass in a mass ratio of 1:(1.5-2.5); the sulfate activating component is a mixture of anhydrous sodium sulfate and aluminum sulfate in a mass ratio of (3-5):1; the composite retarding activating component is a mixture of citric acid and boric acid in a mass ratio of (1-2):

1.

5. The sludge solidifying agent according to claim 1, characterized in that, In the auxiliary curing agent, sodium lignosulfonate has a molecular weight of 8000-15000.

6. The sludge solidifying agent according to claim 1, characterized in that, The modified bentonite is sodium-based bentonite modified with hexadecyltrimethylammonium bromide.

7. The sludge solidifying agent according to claim 6, characterized in that, The modified bentonite is prepared by: crushing and sieving sodium-based bentonite to a particle size ≤50μm, adding a 2-5% (w / w) aqueous solution of hexadecyltrimethylammonium bromide, with a solid-liquid ratio of 1:(5-8), stirring and reacting at 60-70℃ for 2-3 hours, and then filtering, drying, and crushing to obtain the modified bentonite.

8. The sludge solidifying agent according to claim 1, characterized in that, The graphene quantum dots have a particle size of 5-20 nm.

9. The sludge solidifying agent according to any one of claims 1-8, characterized in that, The preparation method of the sludge solidification agent includes the following steps: Step 1: Weigh each component according to the formula and set aside. Control the preparation environment temperature at 20-25℃ and the relative humidity at 40-60%. Step 2: Add the modified multi-source industrial solid waste and modifier into a mixer and stir at a speed of 150-200 r / min for 15-20 min to obtain mixture A; Step 3: Add the synergist to mixture A, adjust the stirring speed to 250-300 r / min, and stir for 20-30 min to obtain mixture B; Step 4: Add auxiliary curing agent to mixture B, adjust the stirring speed to 180-220 r / min, continue stirring for 10-15 min, after mixing evenly, crush and sieve to a particle size ≤60μm to obtain the sludge curing agent.

10. The sludge solidifying agent according to claim 1, characterized in that, The amount of the sludge solidifying agent added to the sludge is 8-15% of the dry weight of the sludge.

Images