Preparation method and application of industrial waste residue composite solidified dredged sludge

Abstract

The present invention belongs to the technical field of sludge resource application, and specifically discloses a preparation method and application of industrial waste residue composite solidified dredged sludge. It comprises: industrial waste residue, auxiliary modified materials, sludge dry soil, coarse sand, and cement are mixed according to a preset ratio; the above ingredients are sequentially added to a reaction container, and then an appropriate amount of water is added to prepare modified sludge with a certain initial moisture content; the modified sludge is sequentially stirred and suffocated; the modified sludge after suffocation is placed in a cool place to dry moderately until the soil is no longer viscous, and then the modified sludge is transferred to a vegetation container, grass seeds are sown into the soil, and vegetation experiments and indoor anti-scour simulations are carried out. The present invention solves the problem of treatment and disposal of river and lake dredged sludge and industrial waste residue, and uses the modified sludge for slope ecological protection, which has a good slope protection and ecological restoration effect, realizes the resource recycling of dredged sludge and industrial waste residue, and has good environmental benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of sludge resource application, and more specifically, relates to a preparation method and application of industrial waste residue composite solidified dredged sludge. Background Art

[0002] The long-term accumulation of silt at the bottom of rivers can significantly impact the flow of water. Furthermore, river and lake silt is also an endogenous source of water pollution, such as black and odorous water bodies. Currently, a large number of river and lake silt dredging projects are underway, and with large amounts of silt being excavated, how to deal with this dredged silt is an urgent issue.

[0003] If industrial waste is directly dumped without treatment after generation, it will occupy a large amount of land. If dumped, harmful components such as heavy metals in ineffectively treated industrial waste will contaminate the soil. Pollutants accumulated in the soil, when exposed to rain, will enter surface runoff and groundwater, posing a threat to nature and humans. Furthermore, industrial solid waste can disrupt the ecological balance within the soil. Soil is a habitat for many microorganisms such as bacteria and fungi. Industrial solid waste, especially hazardous solid waste, can cause soil deterioration through acidification, alkalization, and hardening. In severely polluted areas, even vegetation cannot grow. The harmless treatment and resource utilization of industrial waste are also currently being studied by researchers in various fields.

[0004] Based on the above defects and deficiencies, this field urgently needs to provide a preparation method of typical industrial waste residue composite solidified dredged sludge and its product application, and use the modified sludge for slope ecological protection, to achieve good slope protection and ecological restoration effects, thereby solving the treatment and disposal problems of river and lake dredged sludge and industrial waste residue. Summary of the Invention

[0005] In response to the above defects or improvement needs of the prior art, the present invention provides a preparation method and application of industrial waste residue composite solidified dredged sludge, which realizes the resource utilization of industrial waste residue and dredged sludge, solves the problems of industrial waste residue and dredged sludge treatment and disposal, and at the same time, the slope protection soil has good fertility, which can meet the requirements of plant growth. In addition, the slope protection soil has a certain adsorption capacity for heavy metals, has vegetation ability and anti-scouring ability, and can achieve better results when used in combination with vegetation, play a good slope protection and ecological restoration effect, and has good environmental benefits.

[0006] To achieve the above object, according to one aspect of the present invention, a method for preparing industrial waste residue composite solidified dredged sludge is proposed, comprising the following steps:

[0007] S1 mixes industrial waste residue, auxiliary modified materials, silt dry soil, coarse sand and cement according to a preset ratio;

[0008] S2: adding the ingredients obtained in step S1 to the reaction container in sequence, and then adding an appropriate amount of water to prepare a modified sludge with a certain initial moisture content;

[0009] S3 sequentially stirs and suffocates the modified sludge;

[0010] S4 Place the modified silt after the stuffing treatment in a cool place to dry moderately until the soil is no longer sticky, transfer the modified silt to a vegetation container, sow grass seeds into the soil, and conduct vegetation experiments and indoor anti-scour simulations.

[0011] As further preferred, in step S1, the mass of the industrial waste slag accounts for 0.5 to 2.5% of the mass of the dry sludge soil;

[0012] The industrial waste residue includes slag and phosphogypsum, wherein the slag includes CaO, and the content of CaO is 50-60% of the slag;

[0013] The phosphogypsum includes calcium sulfate dihydrate, wherein the content of the calcium sulfate dihydrate is 700-90% of the phosphogypsum.

[0014] As further preferred, the auxiliary modification materials include: polyvinyl acetate emulsion, green vitriol, activated carbon, attapulgite, fertilizer, and γ-aminopropyltriethoxysilane.

[0015] As a further preferred embodiment, the mass proportion of the polyvinyl acetate emulsion is 3-5%, the mass proportion of the green vitriol is 8-10%, the mass proportion of the activated carbon is 10-15%, the mass proportion of the fertilizer is 3-5%, the mass proportion of the γ-aminopropyltriethoxysilane is 3-5%, and the rest is attapulgite.

[0016] As further preferred, the available nitrogen in the solidified soil is ≥100 mg / kg, the available phosphorus in the solidified soil is ≥8 mg / kg, and the organic matter in the solidified soil is ≥20 g / kg.

[0017] As a further preferred embodiment, the specification of the attapulgite is 200-800 mesh;

[0018] The mass of the coarse sand accounts for 30-40% of the mass of the dry silt soil.

[0019] As a further preferred embodiment, the vegetation experiment includes: placing the modified silt soil into a vegetation container, evenly sowing grass seeds into the vegetation container, sowing 55 to 80 seeds in each vegetation container, placing it on a sunny and well-ventilated platform for cultivation for about 14 days, and placing the vegetation container at 15 to 45 degrees to simulate the vegetation effect of slope protection soil under different slopes.

[0020] As a further preferred embodiment, the indoor anti-scour simulation includes: installing a sprinkler water supply device, using a rainfall simulation system to control the rainfall intensity, determining the rainfall duration by recording the time, collecting the remaining mud in the vegetation container after the experiment, and placing it in an oven for drying and weighing, and calculating the amount of sediment lost during the scouring process.

[0021] As a further preferred embodiment, the rainfall intensity is adjusted to 3.0 mm / h, and the total duration of each rainfall is 25 minutes. At the same time, 13 minutes after the start of the rainfall, the slope runoff is collected once every 1 minute, 2 minutes, 3 minutes, and 4 minutes using a mud and water collection box, for a total of 5 times.

[0022] According to another aspect of the present invention, there is also provided an application of a product prepared by the above preparation method in slope ecological protection.

[0023] In general, the above technical solutions conceived by the present invention have the following technical advantages compared with the existing technology:

[0024] 1. The present invention adopts a method for preparing a new slope protection soil by adding a water-resistant plasticizer and auxiliary materials, which can not only solve the problem of treatment and disposal of industrial waste residues, but also utilize the solidification effect of industrial waste residues to replace the commonly used solidification material - cement. In addition, the modified silt is used for slope ecological protection, which can save conventional materials such as gravel, achieve good slope protection and ecological restoration effects, and have good environmental benefits.

[0025] 2. The slope protection soil obtained by the present invention has good fertility, a certain adsorption capacity for heavy metals, high strength, vegetation ability and anti-scouring ability. It can achieve better results when used in combination with vegetation. It has certain feasibility of ecological slope protection application and realizes the resource utilization of dredged silt and industrial waste.

[0026] 3. In the present invention, the sludge modified with two industrial waste residues, phosphogypsum and slag, has three nutritional indicators, namely organic matter, available nitrogen, and available phosphorus, which can meet the standards of "Landscaping Planting Soil CJ / T340-2016". At the same time, the modified soil under vegetation coverage has higher organic matter and nitrogen contents. Compared with the modified soil not covered by vegetation, the organic matter content is about 30% higher and the available nitrogen content is about 15% higher. The addition of sand increases the porosity and bulk density of the modified soil, and increases the germination speed of the modified soil. At a slope of 30° and a sand content of 35%, the germination rate of the modified soil reaches 85.45%. The modified sludge can have a certain adsorption effect on lead ions, with a removal rate of 25%. The sludge modified with industrial waste residues has the ability to grow vegetation and resist scour. When used in combination with vegetation, it can achieve better results and has certain feasibility for ecological slope protection applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention relates to a method for preparing composite solidified dredged sludge from industrial waste residue. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0029] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing industrial waste residue composite solidified dredged sludge, comprising the following steps:

[0030] Step 1: Industrial waste residue, auxiliary modification materials, silt, coarse sand, and cement are mixed according to a predetermined ratio. In a preferred embodiment of the present invention, the weight ratio of each component in the mix is: industrial waste residue 2-10%, auxiliary modification materials 1-5%, silt, coarse sand 50-55%, coarse sand 10-25%, and cement 5-13%.

[0031] In this step, industrial waste residue includes slag and phosphogypsum. Generally, in preferred embodiments of the present invention, the mass of industrial waste residue accounts for 0.5-2.5% of the mass of the dried silt soil. This and other materials can be adaptively adjusted to meet the requirements of the solidified soil pH, available nitrogen, available phosphorus, and organic matter content in the "Landscaping Planting Soil CJ / T340-2016" standard to meet the standards.

[0032] In a preferred embodiment of the present invention, the industrial waste slag comprises 2.0% slag and 1.5% phosphogypsum. The slag is primarily composed of CaO, with a content of 50-60%, while the phosphogypsum has a particle size of 0.15 mm and a chemical composition of calcium sulfate dihydrate (CaSO4·2H2O), with a content of 70-90%.

[0033] Furthermore, in a preferred embodiment of the present invention, the auxiliary modification materials include: VAc emulsion (polyvinyl acetate emulsion), green vitriol, activated carbon, fertilizer, and KH-550 (γ-aminopropyltriethoxysilane), among which the mass proportions of VAc emulsion (polyvinyl acetate emulsion), green vitriol, activated carbon, attapulgite, fertilizer, and KH-550 (γ-aminopropyltriethoxysilane) are 3-5%, 8-10%, 10-15%, 3-5%, and 3-5%, respectively, and the rest is attapulgite.

[0034] More preferably, the specification of the attapulgite is 200-800 mesh.

[0035] Further preferably, the fertilizer is a decomposed and fermented feces organic fertilizer, such as chicken manure, duck manure, pig manure, etc. In the present invention, the process and method of decomposition and fermentation are conventional technical means and do not fall within the scope of protection of the present invention. For example, in one embodiment, chicken manure can be used for decomposition and fermentation to prepare fertilizer, specifically: pig manure and auxiliary materials are mixed evenly according to a carbon-nitrogen ratio of 1:20-30 to obtain mixture A, fermentation bacteria, humic acid, rice bran, brown sugar powder, and fermentation-specific waste molasses are mixed evenly to obtain mixture B, and then mixture A is mixed with mixture B to obtain fermentation material, and the fermentation material is placed on the fermentation bed of the fermentation equipment for fermentation to obtain decomposed pig manure organic fertilizer. Among them, the auxiliary material can be prepared by crushing plant straw. Of course, other methods of preparing organic fertilizers through decomposition and fermentation are also applicable to the present invention.

[0036] Further preferably, the mass of the coarse sand accounts for 30-40% of the mass of the dry silt soil.

[0037] Step 2: Add the ingredients obtained in step 1 to the reaction container in sequence, and then add an appropriate amount of water to prepare a modified sludge with a certain initial moisture content.

[0038] In this step, the initial moisture content of the modified sludge is 55%.

[0039] Step 3: Stirring and stewing the modified sludge in sequence. More specifically, the modified sludge with a certain moisture content is stirred for 1 to 1.5 hours using a stirrer and then stewed for 22 to 24 hours.

[0040] Step 4: Place the modified silt after the sterilization treatment in a cool place to dry moderately until the soil is no longer sticky, then transfer the modified silt to a vegetation container, sow grass seeds into the soil, and conduct vegetation experiments and indoor anti-scour simulations.

[0041] In this step, the vegetation experiment is to put the modified silt soil into a square plastic box, evenly sow grass seeds in the box, sow 55 to 80 seeds in each culture box, and place it on a sunny and well-ventilated platform for cultivation for about 14 days. The square plastic box is placed at 15 to 45 degrees to simulate the vegetation effect of slope protection soil under different slopes. The indoor anti-scour simulation is to install a sprinkler water supply device and use a rainfall simulation system to control the rainfall intensity. The rainfall duration is determined by recording the time. After the experiment, the remaining mud is collected and placed in an oven for drying and weighing, and the amount of sediment lost during the scouring process is calculated. The rainfall intensity is adjusted to 3.0 mm / h, and the total duration of each rainfall is 25 minutes. At the same time, 13 minutes after the start of the rainfall, the slope runoff is collected once every 1 minute, 2 minutes, 3 minutes, and 4 minutes using a mud and water collection box, and collected 5 times in total.

[0042] In addition, the product obtained by the preparation method of the present invention has an effective nitrogen content of ≥100 mg / kg in the solidified soil of the modified silt, an available phosphorus content of ≥8 mg / kg in the solidified soil of the modified silt, and an organic matter content of ≥20 g / kg in the solidified soil of the modified silt, all of which meet the pH, effective nitrogen, available phosphorus and organic matter content in the solidified soil in the "Garden Greening Planting Soil CJ / T340-2016" standard.

[0043] Furthermore, the present invention prepares a new type of slope protection soil by adding a water-resistant plasticizer and auxiliary materials, which not only solves the problem of treatment and disposal of industrial waste residues, but also can utilize the solidification effect of industrial waste residues to replace the commonly used solidification material - cement. In addition, the modified silt is used for slope ecological protection, which can save conventional materials such as gravel, achieve good slope protection and ecological restoration effects, and have good environmental benefits.

[0044] Example 1

[0045] The modified sludge is composed of industrial waste, auxiliary modification materials, dried silt, coarse sand, cement, and other raw materials. After adding these materials in a certain proportion to a reaction vessel, an appropriate amount of water is added to prepare a modified sludge with an initial moisture content of 55%. After stirring with a stirrer for 1 hour, the modified sludge is allowed to air dry in a cool place until the soil is no longer sticky. The modified sludge is then transferred to a planting container, and grass seeds are sown into the soil. The grass is allowed to grow to 3-4 cm, and then vegetation experiments and indoor scour resistance simulations are carried out.

[0046] The industrial waste slag has a slag content of 2.0% and a phosphogypsum content of 1.5%. The slag is mainly composed of CaO, with a content of 50-60%. The phosphogypsum has a particle size of 0.15 mm and a chemical composition of calcium sulfate dihydrate (CaSO4·2H2O), with a content of 70-90%.

[0047] The auxiliary modification materials include: 1.5% PVAc emulsion (polyvinyl acetate emulsion), 1% green vitriol, 2% activated carbon, 2% attapulgite, 3% fertilizer, and 1% KH-550 (γ-aminopropyltriethoxysilane).

[0048] The specification of the attapulgite soil is 200-800 meshes, and the fertilizer is organic fertilizer such as decomposed and fermented chicken manure.

[0049] The amount of coarse sand mixed is 40%.

[0050] The pH, available nitrogen, available phosphorus and organic matter in the solidified soil refer to the standard "Garden Greening Planting Soil CJ / T340-2016".

[0051] The vegetation experiment involved placing modified silt soil in square plastic boxes and evenly sowing grass seeds. Each box contained 55 to 80 seeds and was placed on a sunny, well-ventilated platform for approximately 14 days. The boxes were positioned at a 15-degree angle to simulate the vegetation effects of slope protection soil on various slopes.

[0052] The indoor anti-scour simulation is to install a sprinkler water supply device and use a rainfall simulation system to control the rainfall intensity, and determine the rainfall duration by recording the time. After the experiment, the remaining mud is collected and placed in an oven for drying and weighing, and the amount of sediment lost during the scour process is calculated.

[0053] The rainfall intensity is adjusted to 3.0 mm / h, and the total duration of each rainfall is 25 minutes. At the same time, 13 minutes after the start of the rainfall, the slope runoff is collected once every 1 minute, 2 minutes, 3 minutes, and 4 minutes using a mud and water collection box, for a total of 5 times.

[0054] Analysis and conclusion: (1) The three nutritional indicators of organic matter (≥20g / kg), available nitrogen (≥100mg / kg), and available phosphorus (≥8mg / kg) of the sludge modified with two industrial waste residues, phosphogypsum and slag, all meet the standards of "Landscaping Planting Soil CJ / T340-2016". (2) The modified soil under vegetation cover has higher organic matter and nitrogen contents. Compared with the modified soil without vegetation cover, the organic matter content is about 40% higher and the available nitrogen content is about 20% higher. (3) The addition of sand increases the porosity and bulk density of the modified soil, and increases the germination speed of the modified soil. At a slope of 15° and a sand content of 40%, the germination rate of the modified soil reaches 90.91%. (4) The modified sludge can have a certain adsorption effect on lead ions, with a removal rate of 24%. (5) The silt modified by industrial waste residue has the ability to grow vegetation and resist erosion. When used in combination with vegetation, it can achieve better results and has certain feasibility for application in ecological slope protection.

[0055] Example 2

[0056] The modified sludge is composed of industrial waste, auxiliary modification materials, dried silt, coarse sand, cement, and other raw materials. After adding these materials in a certain proportion to a reaction vessel, an appropriate amount of water is added to prepare a modified sludge with an initial moisture content of 55%. After stirring with a stirrer for 1 hour, the modified sludge is allowed to air dry in a cool place until the soil is no longer sticky. The modified sludge is then transferred to a planting container, and grass seeds are sown into the soil. The grass is allowed to grow to 3-4 cm, and then vegetation experiments and indoor scour resistance simulations are carried out.

[0057] The industrial waste slag has a slag content of 2.5% and a phosphogypsum content of 2.0%. The slag is mainly composed of CaO, with a content of 50-60%. The particle size of the phosphogypsum is 0.15 mm, and the chemical composition is calcium sulfate dihydrate (CaSO4·2H2O), with a content of 70-90%.

[0058] The auxiliary modification materials include: 1.5% PVAc emulsion (polyvinyl acetate emulsion), 1% green vitriol, 2% activated carbon, 2% attapulgite, 3% fertilizer, and 1% KH-550 (γ-aminopropyltriethoxysilane).

[0059] The specification of the attapulgite soil is 200-800 meshes, and the fertilizer is organic fertilizer such as decomposed and fermented chicken manure.

[0060] The amount of coarse sand mixed is 35%.

[0061] The pH, available nitrogen, available phosphorus and organic matter in the solidified soil refer to the standard "Garden Greening Planting Soil CJ / T340-2016".

[0062] The vegetation experiment involved placing modified silt soil in square plastic boxes and evenly sowing grass seeds. Each box contained 55 to 80 seeds and was placed on a sunny, well-ventilated platform for approximately 14 days. The boxes were positioned at a 30-degree angle to simulate the vegetation effects of slope protection soil on various slopes.

[0063] The indoor anti-scour simulation is to install a sprinkler water supply device and use a rainfall simulation system to control the rainfall intensity, and determine the rainfall duration by recording the time. After the experiment, the remaining mud is collected and placed in an oven for drying and weighing, and the amount of sediment lost during the scour process is calculated.

[0064] The rainfall intensity is adjusted to 3.0 mm / h, and the total duration of each rainfall is 25 minutes. At the same time, 13 minutes after the start of the rainfall, the slope runoff is collected once every 1 minute, 2 minutes, 3 minutes, and 4 minutes using a mud and water collection box, for a total of 5 times.

[0065] Analysis and conclusion: (1) The three nutritional indicators of organic matter (≥20g / kg), effective nitrogen (≥100mg / kg), and available phosphorus (≥8mg / kg) of the sludge modified with two industrial waste residues, phosphogypsum and slag, all meet the standards of "Landscaping Planting Soil CJ / T340-2016". (2) The modified soil under vegetation cover has higher organic matter and nitrogen contents. Compared with the modified soil without vegetation cover, the organic matter content is about 30% higher and the effective nitrogen content is about 15% higher. (3) The addition of sand increases the porosity and bulk density of the modified soil, and increases the germination speed of the modified soil. At a slope of 30° and a sand content of 35%, the germination rate of the modified soil reaches 85.45%. (4) The modified sludge can have a certain adsorption effect on lead ions, with a removal rate of 25%. (5) The silt modified by industrial waste residue has the ability to grow vegetation and resist erosion. When used in combination with vegetation, it can achieve better results and has certain feasibility for application in ecological slope protection.

[0066] Example 3

[0067] The modified sludge is composed of industrial waste, auxiliary modification materials, dried silt, coarse sand, cement, and other raw materials. After adding these materials in a certain proportion to a reaction vessel, an appropriate amount of water is added to prepare a modified sludge with an initial moisture content of 55%. After stirring with a stirrer for 1 hour, the modified sludge is allowed to air dry in a cool place until the soil is no longer sticky. The modified sludge is then transferred to a planting container, and grass seeds are sown into the soil. The grass is allowed to grow to 3-4 cm, and then vegetation experiments and indoor scour resistance simulations are carried out.

[0068] The industrial waste slag has a slag content of 2.0% and a phosphogypsum content of 0.5%. The slag is mainly composed of CaO, with a content of 50-60%. The phosphogypsum has a particle size of 0.15 mm and a chemical composition of calcium sulfate dihydrate (CaSO4·2H2O), with a content of 70-90%.

[0069] The auxiliary modification materials include: 1.5% PVAc emulsion (polyvinyl acetate emulsion), 1% green vitriol, 2% activated carbon, 2% attapulgite, 3% fertilizer, and 1% KH-550 (γ-aminopropyltriethoxysilane).

[0070] The specification of the attapulgite soil is 200-800 meshes, and the fertilizer is organic fertilizer such as decomposed and fermented chicken manure.

[0071] The amount of coarse sand mixed is 40%.

[0072] The pH, available nitrogen, available phosphorus and organic matter in the solidified soil refer to the standard "Garden Greening Planting Soil CJ / T340-2016".

[0073] The vegetation experiment involved placing modified silt soil in square plastic boxes and evenly sowing grass seeds. Each box contained 55 to 80 seeds and was placed on a sunny, well-ventilated platform for approximately 14 days. The boxes were positioned at a 45-degree angle to simulate the vegetation effects of slope protection soil on various slopes.

[0074] The indoor anti-scour simulation is to install a sprinkler water supply device and use a rainfall simulation system to control the rainfall intensity, and determine the rainfall duration by recording the time. After the experiment, the remaining mud is collected and placed in an oven for drying and weighing, and the amount of sediment lost during the scour process is calculated.

[0075] The rainfall intensity is adjusted to 3.0 mm / h, and the total duration of each rainfall is 25 minutes. At the same time, 13 minutes after the start of the rainfall, the slope runoff is collected once every 1 minute, 2 minutes, 3 minutes, and 4 minutes using a mud and water collection box, for a total of 5 times.

[0076] Analysis and conclusion: (1) The three nutritional indicators of organic matter (≥20g / kg), available nitrogen (≥100mg / kg), and available phosphorus (≥8mg / kg) of the sludge modified with two industrial waste residues, phosphogypsum and slag, all meet the standards of "Landscaping Planting Soil CJ / T340-2016". (2) The modified soil under vegetation cover has higher organic matter and nitrogen contents. Compared with the modified soil without vegetation cover, the organic matter content is about 24% higher and the available nitrogen content is about 17% higher. (3) The addition of sand increases the porosity and bulk density of the modified soil, and increases the germination speed of the modified soil. At a slope of 45° and a sand content of 40%, the germination rate of the modified soil is 78.18%. (4) The modified sludge can have a certain adsorption effect on lead ions, with a removal rate of 23%. (5) The silt modified by industrial waste residue has the ability to grow vegetation and resist erosion. When used in combination with vegetation, it can achieve better results and has certain feasibility for application in ecological slope protection.

[0077] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing industrial waste residue composite solidified dredged sludge, characterized in that: The following steps are involved: S1 mixes industrial waste residue, auxiliary modified materials, silt dry soil, coarse sand and cement according to a preset ratio; S2: adding the ingredients obtained in step S1 to the reaction container in sequence, and then adding an appropriate amount of water to prepare a modified sludge with a certain initial moisture content; S3 sequentially stirs and suffocates the modified sludge; S4: Place the modified sludge after the stuffing treatment in a cool place to dry moderately until the soil is no longer sticky, transfer the modified sludge to a planting container, sow grass seeds into the soil, and conduct a planting experiment and indoor anti-scour simulation; In step S1, the mass of the industrial waste slag accounts for 0.5-2.5% of the mass of the sludge dry soil; The industrial waste residue includes slag and phosphogypsum, wherein the slag includes CaO, and the content of CaO is 50-60% of the slag; The phosphogypsum includes calcium sulfate dihydrate, wherein the content of the calcium sulfate dihydrate is 70-90% of the phosphogypsum; The auxiliary modification materials include: polyvinyl acetate emulsion, green vitriol, activated carbon, attapulgite, fertilizer, and γ-aminopropyltriethoxysilane; The mass proportion of the polyvinyl acetate emulsion is 3-5%, the mass proportion of the green vitriol is 8-10%, the mass proportion of the activated carbon is 10-15%, the mass proportion of the fertilizer is 3-5%, the mass proportion of the γ-aminopropyltriethoxysilane is 3-5%, and the rest is attapulgite.

2. The method for preparing industrial waste residue composite solidified dredged sludge according to claim 1, characterized in that: The effective nitrogen in the solidified soil of the modified silt is ≥100 mg / kg, the quick-acting phosphorus in the solidified soil of the modified silt is ≥8 mg / kg, and the organic matter in the solidified soil of the modified silt is ≥20 g / kg.

3. The method for preparing industrial waste residue composite solidified dredged sludge according to claim 1, characterized in that: The specification of the attapulgite is 200-800 meshes.

4. The method for preparing industrial waste residue composite solidified dredged sludge according to claim 3, characterized in that: The mass of the coarse sand accounts for 30-40% of the mass of the dry silt soil.

5. The method for preparing industrial waste residue composite solidified dredged sludge according to any one of claims 1 to 4, characterized in that: The planting experiment includes: placing the modified silt soil into planting containers, evenly sowing grass seeds into the planting containers, sowing 55 to 80 seeds in each planting container, placing them on a sunny and well-ventilated platform for cultivation for about 14 days, and placing the planting containers at an angle of 15 to 45 degrees to simulate the planting effect of slope protection soil under different slopes.

6. The method for preparing industrial waste residue composite solidified dredged sludge according to claim 5, characterized in that: The indoor anti-scour simulation includes: installing a sprinkler water supply device, using a rainfall simulation system to control the rainfall intensity, determining the rainfall duration by recording the time, collecting the remaining mud in the vegetation container after the experiment, placing it in an oven for drying and weighing, and calculating the amount of mud and sand lost during the scour process.

7. The method for preparing industrial waste residue composite solidified dredged sludge according to claim 6, characterized in that: The rainfall intensity is adjusted to 3.0 mm / h, and the total duration of each rainfall is 25 minutes. At the same time, 13 minutes after the start of the rainfall, the slope runoff is collected once every 1 minute, 2 minutes, 3 minutes, and 4 minutes using a mud and water collection box, for a total of 5 times.

8. Use of a product prepared by the preparation method according to any one of claims 1 to 7 in slope ecological protection.

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