Phosphogypsum-based kurtosis repair material as well as preparation method and application thereof

Abstract

The invention discloses an ardealite-based kurtosis slope repairing material as well as a preparation method and application thereof. The ardealite-based kurtosis slope repairing material is prepared from the following raw materials in parts by weight: 100 parts of ardealite, 0.5 to 0.8 part of industrial solid waste, 43 to 82 parts of a composting aid, 0.01 to 0.05 part of a microbial agent and 0.2 to 0.5 part of a clustering agent, the preparation method comprises the following steps: mixing the raw materials, composting, fermenting, adding the clustering agent, and granulating. According to the method, the planting performance of the ardealite is improved through chemical remediation and biological remediation technologies, the engineering strength and the clustering performance of the ardealite are enhanced, and finally ecological remediation of the kurtosis slope with the gradient being 1: 1.5-1: 1 can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of slope restoration technology, specifically relating to a phosphogypsum-based slope restoration material, its preparation method, and its application. Background Technology

[0002] Steep slopes with a gradient between 1:1.5 and 1:1, consisting of soil or strongly weathered soft bedrock, are generally referred to as precipitous slopes. These include slopes cut during highway and railway construction, slopes of spoil heaps formed during mining operations, slopes of water conservancy projects, slopes of building foundation pits, and residual slopes formed after natural landslides. Due to the steep structure of precipitous slopes, gravitational potential energy is concentrated, making them prone to landslides, collapses, and debris flows. Furthermore, precipitous slopes, especially man-made ones, are often bare slopes with vegetation cover of less than 5%, resulting in severe soil erosion and biodiversity loss. Therefore, the restoration of precipitous slopes must first address their instability and poor ecological environment; ecological restoration is the final step in precipitous slope management.

[0003] Traditional slope restoration methods typically employ hydroseeding and vegetation concrete. Hydroseeding substrates are generally mixtures of topsoil, organic fertilizer, and grass seeds, which are prone to detachment under gravity or heavy rain. On steep slopes with a gradient greater than 60°, the adhesion rate is usually less than 30%, and under heavy rain, the substrate erosion rate can reach 40%-60%, with grass seed survival rates below 20%, making effective ecological restoration of steep slopes difficult. Vegetation concrete, with its "concrete skeleton + ecological substrate," suffers from insufficient substrate adhesion and erosion resistance under the gravity and water flow impact of steep slopes. The "concrete skeleton" is prone to high pH levels, nutrient imbalances, and concrete aging and cracking, making it unsuitable for long-term and effective ecological restoration of steep slopes.

[0004] Chinese patent CN120208623A discloses a phosphogypsum-based vegetation concrete and its application method. The concrete comprises the following raw materials by weight percentage: 40-50% sandy clay, 15-20% organic nutrient soil, 15-20% phosphogypsum, 1.5-2.5% cement, 0.2-0.5% water-retaining agent, 0.15-0.20‰ microbial agent, and the balance being water. The application method involves three-stage hydroseeding, with each stage requiring a 15-30 minute settling period. During the third stage, herbaceous and shrub seeds are added to the phosphogypsum-based vegetation concrete. However, this method is only suitable for general slopes, and its repair capacity is limited for steep slopes.

[0005] Chinese patent CN116986879A discloses a novel four-layer phosphogypsum-based sprayable material for revegetating steep slopes. From top to bottom, it consists of a bottom fixing layer, a middle nutrient layer, an upper planting layer, and a surface maintenance layer. The mass percentages of phosphogypsum in the four layers are 85-99%, 60-75%, 30-60%, and 7-15%, respectively. This material absorbs a large amount of phosphogypsum and allows for direct spraying without mesh on slopes with a gradient of less than 80°, significantly reducing construction costs and difficulty. However, each layer requires separate preparation and formulation of the raw materials, resulting in a complex structure and a relatively complicated on-site construction procedure.

[0006] Therefore, it is necessary to develop a restoration material that takes into account both ecological functions and engineering performance, so as to adapt to the complex environment of slope restoration and improve the ecological and safety benefits of slope restoration. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a phosphogypsum-based slope restoration material, its preparation method, and its application. This material utilizes chemical and biological remediation techniques to improve the planting performance of phosphogypsum and enhance its engineering strength and agglomeration properties, ultimately achieving ecological restoration of slopes.

[0008] To achieve the above objectives, the present invention provides a phosphogypsum-based slope restoration material, comprising the following raw materials in parts by weight: 100 parts by weight of phosphogypsum, 0.5-0.8 parts by weight of industrial solid waste, 43-82 parts by weight of composting aid, 0.01-0.05 parts by weight of microbial agent, and 0.2-0.5 parts by weight of a flocculating agent.

[0009] Preferably, the phosphogypsum-based slope repair material further includes water, such that the water content of the final phosphogypsum-based slope repair material is 25-30%.

[0010] Preferably, the phosphogypsum is aged phosphogypsum stored for 3-6 years, with a water content of 10-15% and a CaSO4·2H2O content of 80-85%.

[0011] Preferably, the industrial solid waste is one or more of boron mud, alkali slag, and electroplating waste.

[0012] More preferably, the industrial solid waste is composed of boron mud and electroplating waste residue in a mass ratio of 1:1.

[0013] More preferably, the magnesium oxide content in the boron mud is 35-40%, and the ferric oxide content in the electroplating waste residue is 22-25%.

[0014] Preferably, the composting aid is one or more of kitchen waste, animal manure, sawdust, and straw.

[0015] More preferably, the particle size of the composting aid is 40-60 μm.

[0016] More preferably, the kitchen waste mainly includes leftover food, as well as some fruit peels and vegetable scraps; the animal manure is a mixture of cow manure and sheep manure in a mass ratio of 5:1; the wood chips are a mixture of sawdust and wood shavings in a mass ratio of 1:1; and the straw is a mixture of corn stalks and rice straw in a mass ratio of 1:3.

[0017] Preferably, the effective viable count of the microbial agent is 1.2*10⁻⁶. 10 ufc / mL - 3.0*10 10 Between ufc / mL.

[0018] More preferably, the microbial agent is one or more of Alcaligenes mucosae, myxobacteria, Actinomyces violaceum, Flavobacterium brevesense, Flavobacterium ovalis, and Odontomonas orange.

[0019] More preferably, the microbial agent is composed of *Actinomyces violaceae*, *Odontospira*, and *Alcaligenes mucosa* in a mass ratio of (2-4):(3-5):(2-4).

[0020] Preferably, the agglomerating agent is one or more of the following: phosphorus-based water-reducing agent, yellow phosphorus tailings powder, phosphate rock tailings powder, bentonite, or kaolin.

[0021] More preferably, the phosphorus-based water-reducing agent is one or more of the following: high-performance phosphate water-reducing agent, self-compacting curing phosphate water-reducing agent, and ordinary phosphate water-reducing agent.

[0022] This invention also provides a method for preparing a phosphogypsum-based slope restoration material, comprising the following steps: (1) Mix phosphogypsum with industrial stock to obtain a mixture; (2) Add microbial agents and compost materials to the mixture, mix well and then compost to obtain compost materials; (3) Add a granulating agent to the compost material, mix evenly, and then granulate by disc to obtain phosphogypsum-based slope repair material.

[0023] The present invention also provides an application of a phosphogypsum-based slope restoration material, wherein the application is in the restoration of slopes with a gradient of 1:(1-1.5).

[0024] Preferably, the particle size of the phosphogypsum-based slope repair material is 45-100 mm.

[0025] The beneficial effects of this invention are as follows: 1. This invention uses one or more of the following microbial agents: purple cyst actinomycetes, orange dentomonas, and alkali-producing bacillus. These agents are mixed with phosphogypsum, industrial solid waste, etc., and then composted. This combination of microorganisms has the following advantages: (1) It can control the pH of the acidic phosphogypsum to just between 6 and 7 through microbial fermentation; (2) This combination of microorganisms can bring better gelling ability to phosphogypsum, ensuring the moisture retention and agglomeration ability of phosphogypsum; (3) After the combination of microorganisms, it can effectively solidify the mineral raw materials and heavy metals in the phosphogypsum that are added later, ensuring environmental safety; (4) It can provide nitrogen to phosphogypsum more quickly and efficiently, providing a good environment for subsequent plant growth.

[0026] 2. The addition of boron mud and electroplating waste can effectively alleviate the caking phenomenon after the phosphogypsum pellets are formed, which is conducive to plant survival; the addition of phosphorus-based water-reducing agent can shorten the plasticization time of phosphogypsum pellets; the addition of composting aid can effectively...

[0027] 3. This invention can process a portion of phosphogypsum, reducing the environmental impact of phosphogypsum. It can also be effectively used in slope restoration to alleviate soil weathering and prevent natural disasters. Attached Figure Description

[0028] Figure 1 The images show the slope restoration process. The left image shows the slope after restoration using the phosphogypsum-based slope restoration material prepared in Example 2, and the right image shows the slope after restoration using the phosphogypsum-based slope restoration material prepared in Comparative Example 7. Detailed Implementation

[0029] The technical solution of the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention should be determined by the contents of the claims. Modifications and substitutions made by those skilled in the art to the technical solution of the present invention without creative effort all fall within the scope of protection of the present invention.

[0030] In the following embodiments, the phosphogypsum was sourced from Yidu Xingfa Company, and was aged phosphogypsum that had been stored for 3 years, with a moisture content of 13% and a CaSO4·2H2O content of 86%. The boron mud was sourced from Liaoning Borda Technology Co., Ltd., and had a moisture content of 65% and a magnesium oxide content of 36%. The electroplating waste residue comes from Shandong Jingong Company, with a moisture content of 75%, a ferric oxide content of 23%, and a particle size of 34-47μm; The yellow phosphorus tailings powder is from Jixing Chemical, with a moisture content of 5%, a calcium fluorosilicate content of 53%, and a particle size of 78-94μm after grinding. The phosphate rock tailings powder is sourced from Dongsheng Chemical Co., Ltd., with a moisture content of 7%, a silica content of 47%, and a particle size of 36-87 μm.

[0031] Example 1 A phosphogypsum-based slope restoration material is composed of the following raw materials in parts by weight: 100 parts by weight of phosphogypsum, 0.8 parts by weight of industrial solid waste, 54 parts by weight of composting agent, 0.03 parts by weight of microbial agent, 0.47 parts by weight of a flocculating agent, and an appropriate amount of water. The preparation method is as follows: (1) Boron mud and electroplating waste residue are mixed at a mass ratio of 1:1 as industrial solid waste; (2) Add the industrial solid waste obtained in step (1) to the phosphogypsum and stir to mix evenly to obtain a mixture; (3) Mix purple cyst actinomycetes, orange odontomonads, and alcaligenes mycotoxin at a mass ratio of 3:4:3 to obtain a microbial inoculum with an effective viable count of 1.2*10⁻⁶. 10 ufc / mL; (4) Mix cow manure, sheep manure, kitchen waste and straw in a mass ratio of 5:1:3:2 and crush them to a particle size of 54-97 mm to obtain composting aid; (5) Add microbial inoculants to the mixture, mix well, add composting aids, mix well, and compost for 40 days to obtain compost material, while maintaining the temperature of the compost pile at 50℃-60℃. (6) Mix phosphorus-based water-reducing agent, high-performance phosphate water-reducing agent, yellow phosphorus tailings powder, and kaolin in a mass ratio of 0.1:5:1 as a flocculant; (7) Add a granulating agent to the compost material, mix well and place it in a disc granulator. Granulate at an inclination angle of 47° and a rotation speed of 13 rpm / min. Spray water while granulating to obtain pellets of phosphogypsum-based slope repair material, wherein the amount of water is 2.3%.

[0032] Example 2 A phosphogypsum-based slope restoration material is composed of the following raw materials in parts by weight: 100 parts by weight of phosphogypsum, 0.5 parts by weight of industrial solid waste, 43 parts by weight of composting aid, 0.01 parts by weight of microbial agent, 0.2 parts by weight of flocculating agent, and an appropriate amount of water. Preparation method: (1) Add boron mud as industrial solid waste to phosphogypsum and stir to mix evenly to obtain a mixture; (2) Mix and crush cow manure and sheep manure to a particle size of 59-80 mm to obtain composting aid; (3) Add myxobacteria (effective viable count of 1.5*10⁻⁶) to the mixture. 10 Mix the 1000 ufc / mL) as a microbial aid, then add the crushed kitchen waste as a composting aid, mix well, and compost for 50 days to obtain compost material, while maintaining the temperature of the compost pile at 50-60℃. (6) Add high-performance phosphate water-reducing agent to the compost material as a granulating agent, mix well and place it in a disc granulator, granulate at an inclination angle of 47° and a rotation speed of 13 rpm / min, spray water while granulating, and obtain pellets of phosphogypsum-based slope repair material, wherein the amount of water is 2.2%.

[0033] Example 3 A phosphogypsum-based slope restoration material is composed of the following raw materials in parts by weight: 100 parts by weight of phosphogypsum, 0.6 parts by weight of industrial solid waste, 82 parts by weight of composting aid, 0.05 parts by weight of microbial agent, 0.5 parts by weight of flocculating agent, and an appropriate amount of water. Preparation method: (1) Mix alkali residue and electroplating waste residue at a mass ratio of 1:1 as industrial solid waste; (2) Add the industrial solid waste obtained in step (1) to the phosphogypsum and stir to mix evenly to obtain a mixture; (3) Mix *Actinomyces violaceum*, *Flavobacterium breve*, and *Vitamin Ovo* in a mass ratio of 3:4:3 to obtain a microbial inoculum with an effective viable count of 3.0*10⁻⁶. 10 ufc / mL; (4) Mix kitchen waste, wood chips and straw in a mass ratio of 7:1:2 and crush them to a particle size of 74 mm to obtain composting aid; (5) Add microbial inoculants to the mixture, mix well, add composting aids, mix well, and compost for 38 days to obtain compost material, while maintaining the temperature of the compost pile at 50-60℃. (6) Add phosphate rock tailings powder to the compost material as a granulating agent, mix well and place it in a disc granulator, granulate at an inclination angle of 47° and a rotation speed of 13 rpm, spray water while granulating, and obtain pellets of phosphogypsum-based slope repair material, wherein the amount of water is 2.2%.

[0034] Example 4 A phosphogypsum-based slope restoration material is composed of the following raw materials in parts by weight: 100 parts by weight of phosphogypsum, 0.7 parts by weight of industrial solid waste, 65 parts by weight of composting agent, 0.02 parts by weight of microbial agent, 0.3 parts by weight of flocculating agent, and an appropriate amount of water. Preparation method: (1) Boron mud, alkali slag and electroplating waste residue are mixed in a mass ratio of 1:1:1 as industrial solid waste; (2) Add the industrial solid waste obtained in step (1) to the phosphogypsum and stir to mix evenly to obtain a mixture; (3) Mix *Alcaligenes mucosae*, myxobacteria, *Actinomyces violaceum*, *Vitobacter ovalis*, and *Odontomonas orange* in a mass ratio of 4:3:1:1:1 to obtain a microbial agent with an effective viable count of 1.2*10⁻⁶. 10 ufc / mL; (4) Mix cow manure, sheep manure, kitchen waste, goldenrain tree wood chips and straw in a mass ratio of 5:1:2:1:1 and crush them to a particle size of 82mm to obtain composting aid; (5) Add microbial inoculants to the mixture, mix well, add composting aids, mix well, and compost for 35 days to obtain compost material, while maintaining the temperature of the compost pile at 50-60℃. (6) Mix yellow phosphorus tailings powder, phosphate rock tailings powder, bentonite and kaolin in a mass ratio of 4:4:1:1 as a flocculant; (7) Add phosphate rock tailings powder to the compost material as a granulating agent, mix well and place it in a disc granulator, granulate at an inclination angle of 47° and a rotation speed of 13 rpm, spray water while granulating, and obtain pellets of phosphogypsum-based slope repair material, wherein the amount of water is 2.2%.

[0035] Comparative Example 1 The method and steps are the same as in Example 1, except that no microbial inoculant is added, and pellets of phosphogypsum-based slope restoration material are prepared by composting fermentation.

[0036] Comparative Example 2 The method and steps are the same as in Example 1, except that the effective viable count of the microbial agent is changed to 3.0*10⁻⁶. 10 Pelletized phosphogypsum-based slope restoration material pellets were prepared by composting fermentation at ufc / mL.

[0037] Comparative Example 3 The method and steps are the same as in Example 1, except that the microbial agent is replaced with cyanobacteria, and pellets of phosphogypsum-based slope restoration material are prepared by composting fermentation.

[0038] Comparative Example 4 The method and steps are the same as in Example 1, except that the amount of microbial agent is changed to 0.1 parts by weight, and pellets of phosphogypsum-based slope restoration material are prepared by composting fermentation.

[0039] Comparative Example 5 The method and steps are the same as in Example 1, except that no granulating agent is added, and the compost material is directly used as a phosphogypsum-based slope restoration material without granulation to prepare pellets.

[0040] Comparative Example 6 The method and steps are the same as in Example 1, except that the amount of the agglomerating agent is changed to 2 parts by weight, and the phosphogypsum-based slope repair material is prepared by disc granulation.

[0041] Comparative Example 7 The method and steps are the same as in Example 1, except that freshly produced phosphogypsum is used to prepare pellets of phosphogypsum-based slope restoration material through composting fermentation.

[0042] Comparative Example 8 The method and steps are the same as in Example 1, except that no industrial solid waste is added, and pellets of phosphogypsum-based slope restoration material are prepared by composting and fermentation.

[0043] Comparative Example 9 The method and steps are the same as in Example 1, except that the amount of industrial solid waste is changed to 2 parts by weight, and pellets of phosphogypsum-based slope restoration material are prepared by composting and fermentation.

[0044] Example 5 The phosphogypsum-based slope repair materials prepared in the above examples and comparative examples were used to detect their particle size using a laser particle size analyzer, their moisture content was detected by the drying method, and their erosion resistance was tested using a rainwater erosion resistance curve. The results are shown in Table 1. The phosphogypsum-based slope restoration materials prepared in the above examples and comparative examples were used to restore slopes with a gradient of 1:1.5. The thickness of the restoration material on each square meter of slope was 30 cm. A mesh was installed, with a mesh density of 5*5 cm and at least three meshes per square meter. The physicochemical properties of the surface soil of the slope were tested after six months, with a sampling depth of 25 cm. The results are shown in Table 2. After 180 days, the plant growth was assessed, and soil samples were taken to test for heavy metal content. The plants used were ryegrass and bermudagrass, with a planting density of 50 g seeds per square meter. The results are shown in Table 3. Table 1 Physicochemical properties of phosphogypsum-based slope restoration materials

[0045] Table 2. Physicochemical properties of the remediated soil

[0046] Table 3 Plant growth status

[0047] Table 4 Comparison of heavy metal content after 180 days

[0048] The results showed that the slope restoration materials prepared in Examples 1-4 had small particle sizes and high resistance to rainwater erosion, indicating that they could resist soil erosion under rainwater erosion. Furthermore, after slope restoration using the materials prepared in Examples 1-4, the total phosphorus content, soluble phosphorus, available potassium, water-soluble nitrogen, and TOC in the soil were significantly higher, indicating that they could effectively improve the physical and chemical properties of the soil on the slope. They also promoted plant growth, increased root density and coverage, accelerated the ecological restoration process of the slope, and further enhanced the slope's resistance to gravity and rainwater erosion, reducing soil erosion.

[0049] Comparative Examples 1-4 changed the type and amount of microbial inoculants, Comparative Examples 5-6 changed the amount of flocculating agents, Comparative Example 7 used freshly produced phosphogypsum, and Comparative Examples 8-9 changed the amount of industrial solid waste. The particle size of the prepared slope restoration materials all increased significantly, while the resistance to rainwater erosion decreased significantly. The physical and chemical properties of the soil also decreased significantly. The plant height, root density, and coverage of plants all decreased significantly. This indicates that microbial inoculants, phosphogypsum, industrial solid waste, and flocculating agents work together to restore slopes, improve the physical and chemical properties of the soil, promote plant growth, and achieve ecological restoration of slopes.

Claims

1. A phosphogypsum-based slope restoration material, characterized in that: The raw materials include the following parts by weight: 100 parts by weight of phosphogypsum, 0.5-0.8 parts by weight of industrial solid waste, 43-82 parts by weight of composting aid, 0.01-0.05 parts by weight of microbial agent, and 0.2-0.5 parts by weight of agglomerating agent.

2. The phosphogypsum-based slope restoration material according to claim 1, characterized in that: The phosphogypsum mentioned is aged phosphogypsum that has been stored for 3-6 years.

3. The phosphogypsum-based slope restoration material according to claim 1, characterized in that: The industrial solid waste is one or more of the following: boron mud, alkali slag, and electroplating waste.

4. The phosphogypsum-based slope restoration material according to claim 1, characterized in that: The composting aid is one or more of kitchen waste, animal manure, sawdust, and straw.

5. A phosphogypsum-based slope restoration material according to claim 1, characterized in that: The effective viable count of the microbial agent is 1.2*10⁻⁶. 10 ufc / mL - 3.0*10 10 ufc / mL.

6. A phosphogypsum-based slope restoration material according to claim 5, characterized in that: The microbial agent is one or more of the following: Alcaligenes mucosae, myxobacteria, Actinomyces violaceae, Flavobacterium brevesense, Vibrio ovalis, and Odontomonas orange.

7. A phosphogypsum-based slope restoration material according to claim 6, characterized in that: The microbial agent is composed of purple cyst actinomycetes, orange odontomonads and mucolytic algae-producing bacteria in a mass ratio of (2-4): (3-5): (2-4).

8. A phosphogypsum-based slope restoration material according to claim 1, characterized in that: The agglomerating agent is one or more of the following: phosphorus-based water-reducing agent, yellow phosphorus tailings powder, phosphate rock tailings powder, bentonite, or kaolin.

9. A method for preparing a phosphogypsum-based slope restoration material as described in any one of claims 1-8, characterized in that: Includes the following steps: (1) Mix phosphogypsum with industrial stock to obtain a mixture; (2) Add microbial agents and compost materials to the mixture, mix well and then compost to obtain compost materials; (3) Add a granulating agent to the compost material, mix evenly, and then granulate by disc to obtain phosphogypsum-based slope repair material.

10. The application of a phosphogypsum-based slope restoration material as described in any one of claims 1-8, characterized in that: The application is for repairing steep slopes with a gradient of 1:(1-1.5).

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