A phosphogypsum-based modified clay impermeable material and a preparation method thereof

Abstract

The application discloses a phosphogypsum-based modified clay anti-seepage material and a preparation method thereof, and belongs to the technical field of clay anti-seepage materials. The modified clay anti-seepage material comprises 60-70 wt% of phosphogypsum, 10-15 wt% of ceramic aggregate, 10-15 wt% of carbide slag powder, 5-8 wt% of zeolite powder, 15-20 wt% of silicon-manganese slag powder and 0.8-1 wt% of a hydrophobic organic material; wherein the hydrophobic organic material contains polyacrylamide resin, potassium dihydrogen phosphate, octadecyl trimethyl ammonium chloride and epoxy-modified phenolic resin. The application can greatly improve the utilization efficiency and added value of phosphogypsum, and obtain an anti-seepage material with excellent low permeability, good mechanical strength and volume stability.

Description

Technical Field

[0001] This invention relates to the technical field of clay impermeable materials, and particularly to a phosphogypsum-based modified clay impermeable material and its preparation method. Background Technology

[0002] Polymer-modified clay waterproofing material (TSP) is a high-quality waterproofing material widely used in civil and industrial construction fields such as roof composite waterproofing, indoor waterproofing, landscaping, and site ecological restoration. Its common components include carefully selected graded sand, natural sodium-based bentonite, and special polymers. The natural sodium-based bentonite absorbs water and expands, forming a strong, dense spiderweb-like hydrogel structure with the polymers, resulting in a novel composite waterproofing material with excellent performance and extremely low permeability.

[0003] However, existing TSP materials still have many shortcomings. First, their weather resistance and stability are poor. In high-temperature or humid environments, their structure is prone to change, leading to a decrease in adsorption capacity and mechanical properties. Simultaneously, their acid and alkali resistance is insufficient; under strong acid or alkali conditions, the polymeric modifiers within the TSP are easily decomposed or dissolved, causing material performance failure. Second, during long-term use, the modifiers may gradually be lost due to repeated adsorption-desorption processes, significantly shortening the material's lifespan. Furthermore, TSP also faces challenges in practical applications, such as high construction requirements and high material costs, limiting its widespread use in more scenarios.

[0004] On the other hand, as a large-volume chemical byproduct, phosphogypsum's existing uses mainly include cement additives, road fillers, gypsum boards, building gypsum powder, and gypsum blocks. However, these uses generally suffer from low added value, limited consumption, and susceptibility to pollutant leaching, making it difficult to achieve large-scale, efficient, and high-value utilization of phosphogypsum. Furthermore, existing phosphogypsum-based materials often exhibit inherent defects such as slow strength development, poor water resistance, and poor volume stability, severely impacting their application in seepage prevention and structural engineering.

[0005] Therefore, developing a new type of low-cost, high-performance, environmentally friendly, and complex-condition-suitable seepage-proof material that can consume large quantities of phosphogypsum is of great practical significance and application value. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to propose a novel phosphogypsum-based modified clay seepage-proof material and its preparation method. This preparation method can simultaneously consume industrial solid waste phosphogypsum to form TSP-modified clay, achieving efficient and high-value-added resource utilization of phosphogypsum, creating economic benefits, reducing raw material costs, and alleviating environmental pressure. Furthermore, it effectively solves the problems of insufficient durability and stability of existing TSP materials, significantly improving the long-term performance stability of the material under high temperature, humidity, and acid / alkali environments, and preventing the loss of functional components.

[0007] The technical solution of the present invention is as follows:

[0008] A phosphogypsum-based modified clay impermeable material comprises the following raw material components by weight: 60-70 wt% phosphogypsum, 10-15 wt% ceramic aggregate, 10-15 wt% carbide slag powder, 5-8 wt% zeolite powder, 12-20 wt% ferromanganese slag powder, and 0.8-1 wt% hydrophobic organic material; wherein the ceramic aggregate is granular material obtained from crushing waste ceramics; and the hydrophobic organic material contains polyacrylamide resin, potassium dihydrogen phosphate, octadecyltrimethylammonium chloride, and epoxy-modified phenolic resin.

[0009] In the above technical solutions of this invention, phosphogypsum is used as the main material to realize the resource utilization of solid waste. Simultaneously, under the action of a polymer flocculant, phosphogypsum can form a strong, dense gel structure with other materials. Fine phosphogypsum particles can also form more tortuous seepage paths with other substances, effectively blocking water penetration, reducing the overall permeability coefficient of the material, and improving its self-healing properties, thereby enhancing the material's seepage-proof stability. Ceramic aggregate has high strength and hardness, serving as the skeleton of the seepage-proof material, effectively resisting external pressure and improving the material's compressive strength and durability. To ensure the seepage-proof material maintains a stable structure during use, preventing deformation or damage, it can fill the voids in phosphogypsum-based modified clay, making the internal structure more compact, reducing water penetration channels, thereby lowering the material's permeability coefficient and improving its impermeability. Calcium carbide slag powder accelerates the fusion of raw material components through its excellent exothermic properties, and neutralizes the acidity of phosphogypsum through the alkaline substances generated after exothermic reactions, promoting the full utilization of hydrophobic organic materials. Zeolite powder increases the adsorption capacity of modified clay seepage-proof materials, enhancing their ability to fix Cd and Hg through ion exchange and surface adsorption. It can remove heavy metals and reduce their bioavailability, while also reducing odor diffusion. Hydrophobic organic materials can fully ensure the bonding stability of modified clay impermeable materials, and can form a low surface energy protective film on the material surface to prevent water intrusion, thereby reducing the water absorption rate of the material. It can fill the pores and microcracks inside the material, making the internal structure of the material more compact, reducing the channels for water penetration, lowering the permeability coefficient of the material, and improving its impermeability. Some hydrophobic organic materials can also form good interfacial bonding with other components in phosphogypsum-based materials, playing a role in stress transfer, thereby improving the mechanical properties of the material.

[0010] According to some preferred embodiments of the present invention, in the hydrophobic organic material, the mass ratio of the polyacrylamide resin, potassium dihydrogen phosphate, octadecyltrimethylammonium chloride and epoxy-modified phenolic resin is 1:1:3:1.

[0011] In the above technical solutions of this invention, in the phosphogypsum-based modified clay impermeable material, polyacrylamide resin, potassium dihydrogen phosphate, octadecyltrimethylammonium chloride, and epoxy-modified phenolic resin each play different roles and can work synergistically to improve the impermeability of the material. Polyacrylamide, a high-molecular polymer, has excellent flocculation and bonding properties, which can promote the aggregation of soil particles, forming a stable structure, thereby reducing porosity and water infiltration channels in the soil and improving the material's impermeability. Simultaneously, polyacrylamide can also enhance the material's toughness and durability, making it less prone to cracking under external pressure or environmental changes. Potassium dihydrogen phosphate (KH2PO4) can participate in internal chemical reactions within materials, forming complexes with other components to improve the material's structure and performance. Furthermore, its potassium ions can exchange with ions on the surface of soil particles, altering their surface properties and reducing their surface energy, thus decreasing water adsorption and penetration. Additionally, KH2PO4 may regulate the pH of the material, helping to maintain its chemical stability. Octadecyltrimethylammonium chloride (OCC) is a cationic surfactant with excellent surface activity and hydrophobicity. It can adsorb onto the surface of soil particles or phosphogypsum particles, forming a hydrophobic protective film and reducing surface saturation. Hydrophilicity prevents water intrusion. Simultaneously, it can alter the surface charge of particles through ion exchange, promoting particle aggregation and flocculation, resulting in a denser internal structure and further improving impermeability. Epoxy-modified phenolic resin combines the excellent adhesion of epoxy resin with the good heat resistance of phenolic resin. It can be used as a binder to firmly bond phosphogypsum, clay, and other components together, forming a unified whole and improving the material's strength and stability. Furthermore, epoxy-modified phenolic resin also exhibits good corrosion resistance and water resistance, enhancing the material's durability in harsh environments and preventing damage from water and chemical erosion. In terms of overall function, polyacrylamide resin can agglomerate soil particles and phosphogypsum particles together through flocculation to form a preliminary structural framework. Octadecyltrimethylammonium chloride, through its hydrophobic properties and ion exchange, reduces the hydrophilicity of the particle surface, fills the pores between particles, makes the internal structure of the material more compact, and reduces the channels for water penetration. Potassium dihydrogen phosphate further optimizes the structure and performance of the material by participating in chemical reactions and regulating the surface properties of particles, enhancing the material's impermeability and chemical stability. Epoxy-modified phenolic resin, as a binder, firmly bonds all components together to form a whole with high strength, high durability, and good impermeability. At the same time, its corrosion resistance and water resistance also help to extend the service life of the material. The synergistic effect of the above components can significantly improve the impermeability of phosphogypsum-based modified clay impermeable materials.

[0012] According to some preferred embodiments of the present invention, the particle size of the ceramic aggregate is less than 5 mm.

[0013] According to some preferred embodiments of the present invention, the calcium hydroxide content in the carbide slag powder is above 80 wt%, the free water content is below 10 wt%, and the fineness is 60-100 mesh.

[0014] According to some preferred embodiments of the present invention, the zeolite powder has a fineness of 80-120 mesh, a cation exchange capacity of more than 120 mmol / 100g, and a pH value of 7-8.

[0015] According to some preferred embodiments of the present invention, the specific surface area of ​​the ferrosilicon slag powder is above 400 m² / kg, the sieve residue is below 6 wt%, and the moisture content is below 1 wt%.

[0016] According to some preferred embodiments of the present invention, the epoxy value of the epoxy-modified phenolic resin is 0.15-0.25 eq / 100g.

[0017] This invention further provides a method for preparing the above-mentioned phosphogypsum-based modified clay impermeable material, comprising:

[0018] (1) The phosphogypsum is cleaned and impurities are removed to obtain cleaned phosphogypsum, which is then dried, ball-milled, and passed through a 100-mesh sieve to obtain pretreated phosphogypsum;

[0019] (2) The waste ceramics are crushed until the particle size reaches less than 5 mm to obtain ceramic aggregate;

[0020] (3) Polyacrylamide resin, potassium dihydrogen phosphate, octadecyltrimethylammonium chloride and epoxy-modified phenolic resin are mixed to obtain hydrophobic organic material;

[0021] (4) The pretreated phosphogypsum, the ceramic aggregate, the hydrophobic organic material, and carbide slag powder, zeolite powder, and ferrosilicon slag powder are mixed to obtain the phosphogypsum-based modified clay seepage prevention material.

[0022] According to some preferred embodiments of the present invention, the preparation of the epoxy-modified phenolic resin includes:

[0023] (1) After melting phenol, add sodium hydroxide aqueous solution, then slowly add formaldehyde solution, control the dropping rate so that the reaction temperature does not exceed 70℃, after the dropping is completed, raise the temperature to 80-90℃, keep the temperature for 2-3 hours to obtain phenolic prepolymer;

[0024] (2) Add epichlorohydrin to the phenolic prepolymer, heat to 90-100℃, stir and react for 3-4 hours until the epoxy value of the product reaches 0.15-0.25 eq / 100g, then stop the reaction to obtain the product system;

[0025] (3) Add water to the product system, let it stand and separate into layers, remove the lower aqueous phase, add ethanol to the upper organic phase to dilute, and adjust the pH to 6-7. Then remove excess solvent and water to obtain a brownish-black viscous product, namely epoxy-modified phenolic resin.

[0026] According to some preferred embodiments of the present invention, in the preparation of the epoxy-modified phenolic resin, the amount of phenol is 100 parts by mass, the concentration of sodium hydroxide aqueous solution is 15-25 wt% and the amount is 40-50 parts by mass, the formaldehyde solution is an industrial grade methanol aqueous solution and the amount is 80-100 parts by mass, and the amount of epichlorohydrin is 120-150 parts by mass.

[0027] According to some preferred embodiments of the present invention, obtaining the pretreated phosphogypsum includes: dispersing the phosphogypsum and adding water, then removing surface oil and screening out large impurities, then dispersing the formed phosphogypsum particles and performing multi-stage washing to remove soluble phosphates, fluorides and other impurities from the phosphogypsum, to obtain washed phosphogypsum; drying the washed phosphogypsum at 100-110°C to obtain dried phosphogypsum; ball milling the dried phosphogypsum to 80-120 mesh and passing it through a 100-mesh sieve to obtain the pretreated phosphogypsum.

[0028] The phosphogypsum-based modified clay impermeable material obtained by the above preparation method is a multiphase composite material composed of various components including phosphogypsum, ceramic aggregate, carbide slag powder, zeolite powder, ferromanganese slag powder, and hydrophobic organic materials. Among them, the ceramic aggregate acts as a skeleton, providing support, while other fine-particle materials such as phosphogypsum, carbide slag powder, zeolite powder, and ferromanganese slag powder fill the pores of the skeleton, forming a relatively dense structure. The addition of ceramic aggregate and hydrophobic organic materials such as octadecyltrimethylammonium chloride further fills the voids in the phosphogypsum-based material; it also fills the pores between particles, optimizing the internal pore structure of the material, reducing pore size and making the distribution more uniform, thereby reducing the channels for water penetration and resulting in good interfacial bonding. The fine phosphogypsum particles and other substances can form tortuous seepage paths within the ceramic aggregate, and the phosphorus... The presence of gypsum allows the material to expand to a certain extent upon contact with water, thus providing some closure to micro-cracks and improving the material's self-healing ability and impermeability. Hydrophobic organic materials form a hydrophobic protective film on the material's surface and interior, preventing water intrusion; all of these effectively reduce the material's permeability coefficient and improve its impermeability. Epoxy-modified phenolic resin acts as a binder, firmly bonding the components together to form a good interfacial bond. Polyacrylamide resin, through flocculation, agglomerates particles, further enhancing the bonding force between components and creating a stable overall structure. The synergistic effect of these multiple components results in a material with a low permeability coefficient, high mechanical strength, good water resistance and durability, good self-healing properties, and environmental friendliness.

[0029] The present invention has the following beneficial effects:

[0030] This invention uses phosphogypsum as the main raw material, in conjunction with various solid wastes such as waste ceramics, carbide slag, and ferrosilicon manganese slag, to realize the resource utilization and material recycling of waste, and significantly improve the utilization efficiency and added value of industrial by-products. The resulting phosphogypsum-based modified clay seepage-proof material can be used as an ultra-low permeability seepage-proof material in civil and industrial construction fields such as landfills, industrial slag storage facilities, industrial plants, contaminated sites, and waterways, while saving clay resources and reducing the price of engineering implementation materials.

[0031] This invention introduces inorganic cementing components such as zeolite powder (high CEC characteristics), calcium carbide slag powder, and ferromanganese slag powder, and combines them with hydrophobic organic materials to form a stable and more weather-resistant dense network structure. This structure can effectively resist the erosion of high temperature, humidity and acid and alkaline environments, greatly delay the dissolution and loss of functional components, and has excellent low permeability, good mechanical strength and volume stability. It has low construction requirements and is easy to operate on site, overcoming the problems of rapid degradation of adsorption and mechanical properties and short life of traditional TSP materials under complex conditions.

[0032] The phosphogypsum-based modified clay impermeable material obtained by this invention can effectively adsorb and fix heavy metal ions and pollutants such as ammonium nitrogen in the environment. While preventing seepage, it also has the function of in-situ pollution blocking. It is especially suitable for contaminated sites and ecological restoration projects, and has significant environmental friendliness.

[0033] The preparation process of this invention is environmentally friendly, has good treatment effect, short cycle, and strong feasibility, and has great social, economic and environmental benefits. Attached Figure Description

[0034] Figure 1 The images show a comparison of SEM images of the phosphogypsum-based modified clay impermeable material (b) and natural soil (a) in Example 1. Detailed Implementation

[0035] The technical solutions of the present invention will be further described below with reference to embodiments thereof. The embodiments described below are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0036] The modified phenolic resin used in the following examples was obtained through the following process:

[0037] (1) Add phenol to a three-necked flask equipped with a stirrer, reflux condenser and thermometer, heat to 40-50℃ to melt it, then add a 20wt% sodium hydroxide aqueous solution, stir for 10 min, then slowly add formaldehyde solution (solvent is water), control the dropping rate so that the reaction temperature does not exceed 70℃, after the dropping is completed, raise the temperature to 80-90℃, keep the temperature for 2-3 h to obtain phenolic prepolymer;

[0038] (2) Add epichlorohydrin to the reaction system of step (1), heat to 90-100℃, stir for 3-4 hours, and monitor the reaction progress by taking samples to detect the epoxy value of the product (epoxy equivalents contained in 100g resin). When the epoxy value reaches 0.15-0.25eq / 100g, stop the reaction, add an appropriate amount of deionized water, stir evenly and let stand to separate the layers, remove the lower aqueous phase (containing byproducts such as sodium chloride), add solvent ethanol to dilute the organic phase, adjust the pH to 6-7 with dilute hydrochloric acid, and then remove excess solvent and water by vacuum distillation to obtain a brownish viscous epoxy modified phenolic resin, i.e., the modified phenolic resin.

[0039] The raw material ratio is as follows: 100 parts by weight of phenol, 40-50 parts by weight of 20wt% sodium hydroxide aqueous solution, 80-100 parts by weight of formaldehyde solution (solvent is water, 37wt% industrial grade), and 120-150 parts by weight of epichlorohydrin; in addition, 80-100 parts by weight of deionized water for layering and impurity removal, 60-80 parts by weight of ethanol for dilution, and about 5-10 parts by weight of dilute hydrochloric acid (concentration of 10wt%) for pH adjustment.

[0040] The polyacrylamide resins used in the following examples have a molecular weight between 5 million and 12 million and a degree of hydrolysis between 10% and 35%.

[0041] The calcium carbide slag powder used in the following examples has a Ca(OH)2 content of 80-85 wt%, is an industrial grade II product, has a free water content of ≤10 wt%, and a fineness of 60-100 mesh; the zeolite powder used has a fineness of 80-120 mesh, CEC ≥120 mmol / 100g, pH value of 7-8, specific surface area of ​​ferrosilicon slag powder ≥400 m² / kg, sieve residue ≤6 wt%, and water content ≤1 wt%.

[0042] Example 1

[0043] Phosphogypsum-based modified clay impermeable materials were prepared using the following process:

[0044] (1) Weigh 3kg of phosphogypsum, break it into a paste by stirring the roller of the washing machine, then add clean water, remove the oil stains on the surface by passing through the three-stage grid of the washing machine, then screen out large impurities by passing through the first-stage drum washing machine, and then break up the phosphogypsum particles by rotating the second-stage high-speed drum machine and thoroughly clean the phosphogypsum. Then remove soluble phosphates, fluorides, impurities, etc. from the phosphogypsum by passing through multi-stage cleaning equipment to obtain cleaned phosphogypsum.

[0045] (2) The cleaned phosphogypsum was dried in a drying oven at a temperature of 105°C for 24 hours to obtain dried phosphogypsum; the dried phosphogypsum was ball-milled to 80-120 mesh and passed through a 100-mesh sieve to obtain pretreated phosphogypsum.

[0046] (3) The waste ceramic particles are crushed by a crusher and then transferred to a disc mill to be ground to less than 5 mm to obtain aggregate;

[0047] (4) Mix 20g of polyacrylamide resin, 20g of potassium dihydrogen phosphate, 60g of octadecyltrimethylammonium chloride and 20g of modified phenolic resin to obtain a hydrophobic organic material.

[0048] (5) 600g of pretreated phosphogypsum, 150g of aggregate, 100g of carbide slag powder, 60g of zeolite powder, 150g of ferromanganese slag powder and 80g of hydrophobic organic material are thoroughly mixed and stirred, and filled into a 5cm diameter experimental tube (D50 diameter PE pipe) to obtain phosphogypsum-based modified clay seepage prevention material.

[0049] The obtained phosphogypsum-based modified clay impermeable material was stored for 3 days at 75% humidity and 25℃, and then sent for testing. The test results obtained according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-1999) are shown in Table 1 below:

[0050] Table 1 Detection results of Example 1

[0051]

[0052] As can be seen from Table 1, the parameters of this phosphogypsum-based modified clay seepage prevention material are far superior to those of natural clay.

[0053] The microstructure of the obtained phosphogypsum-based modified clay impermeable material was characterized, and it was compared with that of natural clay, as shown in the attached figure. Figure 1 As shown, the phosphogypsum-based modified clay seepage prevention material has denser interstices in the soil and higher soil strength and structure.

[0054] Example 2

[0055] Phosphogypsum-based modified clay impermeable materials were prepared using the following process:

[0056] (1) Weigh 3kg of phosphogypsum, break it into a paste by stirring the roller of the washing machine, then add clean water, remove the oil stains on the surface by passing through the three-stage grid of the washing machine, then screen out large impurities by passing through the first-stage drum washing machine, and then break up the phosphogypsum particles by rotating the second-stage high-speed drum machine and thoroughly clean the phosphogypsum. Then remove soluble phosphates, fluorides, impurities, etc. from the phosphogypsum by passing through multi-stage cleaning equipment to obtain cleaned phosphogypsum.

[0057] (4) The cleaned phosphogypsum was dried in a drying oven at a temperature of 105°C for 24 hours to obtain dried phosphogypsum.

[0058] (2) The waste ceramic particles are crushed by a crusher and then transferred to a disc mill to be ground to less than 5 mm to obtain aggregate;

[0059] (4) Mix 20g of polyacrylamide resin, 20g of potassium dihydrogen phosphate, 60g of octadecyltrimethylammonium chloride and 20g of modified phenolic resin to obtain a hydrophobic organic material.

[0060] (5) 600g of dried phosphogypsum, 150g of aggregate, 100g of carbide slag powder, 60g of zeolite powder, 150g of ferromanganese slag powder and 80g of hydrophobic organic material are thoroughly mixed and stirred, and then filled into a 5cm diameter experimental tube to obtain phosphogypsum-based modified clay seepage prevention material.

[0061] The obtained phosphogypsum-based modified clay impermeable material was stored for 3 days at 75% humidity and 25℃, and then sent for testing. The test results obtained according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-1999) are shown in Table 2 below:

[0062] Table 2 Detection Results of Example 2

[0063]

[0064] As can be seen from Table 2, the parameters of this phosphogypsum-based modified clay seepage-proof material are far superior to those of natural clay, but not as good as those of Example 1.

[0065] Example 3

[0066] Phosphogypsum-based modified clay impermeable materials were prepared using the following process:

[0067] (1) Weigh 1 kg of phosphogypsum, break up the lumps and stir evenly with a wooden stick to obtain phosphogypsum powder;

[0068] (2) The waste ceramic particles are crushed by a crusher and then transferred to a disc mill to be ground to less than 5 mm to obtain aggregate;

[0069] (3) Mix 20g of polyacrylamide resin, 20g of potassium dihydrogen phosphate, 60g of octadecyltrimethylammonium chloride and 20g of modified phenolic resin to obtain a hydrophobic organic material.

[0070] (4) 600g of phosphogypsum powder, 150g of aggregate, 100g of carbide slag powder, 60g of zeolite powder, 150g of ferromanganese slag powder and 80g of hydrophobic organic material are thoroughly mixed and stirred, and then filled into a 5cm diameter experimental tube to obtain phosphogypsum-based modified clay seepage prevention material.

[0071] The obtained phosphogypsum-based modified clay impermeable material was stored for 3 days at 75% humidity and 25℃, and then sent for testing. The test results obtained according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-1999) are shown in Table 3 below:

[0072] Table 3 Detection results of Example 3

[0073]

[0074] As can be seen from Table 3, the parameters of this phosphogypsum-based modified clay seepage-proof material are far superior to those of natural clay, but not as good as those of Example 2.

[0075] Example 4

[0076] Conventional clay impermeable materials are prepared through the following process:

[0077] Weigh 1 kg of commercially available TSP dry material A (LW-JS01 type), break it up and stir it evenly with a wooden stick to obtain TSP dry material powder; add 80 g of water to the TSP dry material powder according to the product ratio requirements, stir evenly, and obtain conventional clay seepage prevention material.

[0078] The obtained conventional clay impermeable material was stored for 3 days at 75% humidity and 25℃, and then sent for testing. The test results obtained according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-1999) are shown in Table 4 below:

[0079] Table 4 Detection Results of Example 4

[0080]

[0081] As can be seen from Table 4, the modified clay impermeable material has better performance in all parameters than natural clay, but not as good as Example 1.

[0082] Example 5

[0083] Conventional clay impermeable materials are prepared through the following process:

[0084] Weigh 1 kg of commercially available TSP dry material B (SYL003), break it up and stir it evenly with a wooden stick to obtain TSP dry material powder; add 80 g of water to the TSP dry material powder according to the product ratio requirements, stir evenly, and obtain conventional clay seepage prevention material.

[0085] The obtained conventional clay impermeable material was stored for 3 days at 75% humidity and 25℃, and then sent for testing. The test results obtained according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-1999) are shown in Table 5 below:

[0086] Table 5. Detection results of Example 5

[0087]

[0088] As can be seen from Table 5, the modified clay impermeable material has better performance in all parameters than natural clay, but not as good as in Example 1.

[0089] Example 6

[0090] Phosphogypsum-based modified clay impermeable materials were prepared using the following process:

[0091] (1) Weigh 1 kg of the pretreated phosphogypsum obtained in Example 1 after storage, break up the lumps and stir evenly with a wooden stick to obtain the pretreated phosphogypsum;

[0092] (2) The waste ceramic particles are crushed by a crusher and then transferred to a disc mill to be ground to less than 5 mm to obtain aggregate;

[0093] (3) 600g of pretreated phosphogypsum, 150g of aggregate, 100g of carbide slag powder, 60g of zeolite powder and 150g of ferromanganese slag powder are thoroughly mixed and stirred, and then filled into a 5cm diameter experimental tube to obtain phosphogypsum-based modified clay seepage prevention material.

[0094] The obtained phosphogypsum-based modified clay impermeable material was stored for 3 days at 75% humidity and 25℃, and then sent for testing. The test results obtained according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-1999) are shown in Table 6 below:

[0095] Table 6 Detection Results of Example 6

[0096]

[0097] As can be seen from Table 6, the parameters of this phosphogypsum-based modified clay seepage prevention material are far inferior to those of natural clay, but not as good as those of Example 1.

[0098] Example 7

[0099] Phosphogypsum-based modified clay impermeable materials were prepared using the following process:

[0100] (1) Weigh 1 kg of phosphogypsum, break up the lumps and stir evenly with a wooden stick to obtain phosphogypsum powder;

[0101] (2) The waste ceramic particles are crushed by a crusher and then transferred to a disc mill to be ground to less than 5 mm to obtain aggregate;

[0102] (3) 600g of phosphogypsum powder, 150g of aggregate, 100g of carbide slag powder, 60g of zeolite powder and 150g of ferromanganese slag powder are thoroughly mixed and stirred, and then filled into a 5cm diameter experimental tube to obtain phosphogypsum-based modified clay seepage prevention material.

[0103] The obtained phosphogypsum-based modified clay impermeable material was stored for 3 days at 75% humidity and 25℃, and then sent for testing. The test results are shown in Table 7 below:

[0104] Table 7 Detection Results of Example 7

[0105]

[0106] As can be seen from Table 7, the parameters of this phosphogypsum-based modified clay seepage prevention material are far inferior to those of natural clay, but not as good as those of Example 1.

[0107] Example 8

[0108] Phosphogypsum-based modified clay impermeable materials were prepared using the following process:

[0109] (1) Weigh 1 kg of the pretreated phosphogypsum obtained in Example 1 after storage, break up the lumps and stir evenly with a wooden stick to obtain the pretreated phosphogypsum;

[0110] (2) Mix 20g of polyacrylamide resin, 20g of potassium dihydrogen phosphate, 60g of octadecyltrimethylammonium chloride and 20g of modified phenolic resin to obtain a hydrophobic organic material.

[0111] (3) 600g of pretreated phosphogypsum, 100g of carbide slag powder, 60g of zeolite powder, 150g of ferromanganese slag powder and 80g of hydrophobic organic material are thoroughly mixed and stirred, and then filled into a 5cm diameter experimental tube to obtain phosphogypsum-based modified clay seepage prevention material.

[0112] The obtained phosphogypsum-based modified clay impermeable material was stored for 3 days at 75% humidity and 25℃, and then sent for testing. The test results obtained according to the "Standard for Geotechnical Testing Methods" (GB / T 50123-1999) are shown in Table 8 below:

[0113] Table 8 Detection Results of Example 8

[0114]

[0115] As can be seen from Table 8, the parameters of this phosphogypsum-based modified clay seepage-proof material are far superior to those of natural clay, but not as good as those of Example 1.

[0116] It should be noted that the above descriptions are merely preferred embodiments of the present invention and should not limit the scope of protection of the technical solutions of the present invention. Any modifications made to the technical solutions described in the foregoing embodiments, or equivalent substitutions of technical features, by those skilled in the art within the spirit and principles of the present invention, should be included within the scope of protection of the present invention.

Claims

1. A phosphogypsum-based modified clay seepage-proof material, characterized in that, It comprises the following raw material components by weight: 60-70 wt% phosphogypsum, 10-15 wt% ceramic aggregate, 10-15 wt% calcium carbide slag powder, 5-8 wt% zeolite powder, 12-20 wt% ferromanganese slag powder, and 0.8-1 wt% hydrophobic organic material; wherein the ceramic aggregate is granular material obtained from crushing waste ceramics; and the hydrophobic organic material contains polyacrylamide resin, potassium dihydrogen phosphate, octadecyltrimethylammonium chloride, and epoxy-modified phenolic resin.

2. The phosphogypsum-based modified clay seepage-proof material according to claim 1, characterized in that, In the hydrophobic organic material, the mass ratio of polyacrylamide resin, potassium dihydrogen phosphate, octadecyltrimethylammonium chloride, and epoxy-modified phenolic resin is 1:1:3:

1.

3. The phosphogypsum-based modified clay seepage-proof material according to claim 1, characterized in that, in, The ceramic aggregate has a particle size of less than 5 mm; and / or, the calcium hydroxide content in the calcium carbide slag powder is above 80 wt%, the free water content is below 10 wt%, and the fineness is 60-100 mesh; and / or, the fineness of the zeolite powder is 80-120 mesh, the cation exchange capacity is above 120 mmol / 100g, and the pH value is 7-8; and / or, the specific surface area of ​​the ferrosilicon manganese slag powder is above 400 m² / kg, the sieve residue is below 6 wt%, and the water content is below 1 wt%; and / or, the epoxy value of the epoxy-modified phenolic resin is 0.15-0.25 eq / 100g.

4. The method for preparing the phosphogypsum-based modified clay seepage-proof material according to any one of claims 1-3, characterized in that, It includes: (1) The phosphogypsum is cleaned and impurities are removed to obtain cleaned phosphogypsum, which is then dried, ball-milled, and passed through a 100-mesh sieve to obtain pretreated phosphogypsum; (2) The waste ceramics are crushed until the particle size reaches less than 5 mm to obtain ceramic aggregate; (3) Polyacrylamide resin, potassium dihydrogen phosphate, octadecyltrimethylammonium chloride and epoxy-modified phenolic resin are mixed to obtain hydrophobic organic material; (4) The pretreated phosphogypsum, the ceramic aggregate, the hydrophobic organic material, and carbide slag powder, zeolite powder, and ferrosilicon slag powder are mixed to obtain the phosphogypsum-based modified clay seepage prevention material.

5. The preparation method according to claim 4, characterized in that, The preparation of the epoxy-modified phenolic resin includes: (1) After melting phenol, add sodium hydroxide aqueous solution, then slowly add formaldehyde solution, control the dropping rate so that the reaction temperature does not exceed 70℃, after the dropping is completed, raise the temperature to 80-90℃, keep the temperature for 2-3 hours to obtain phenolic prepolymer; (2) Add epichlorohydrin to the phenolic prepolymer, heat to 90-100℃, stir and react for 3-4 hours until the epoxy value of the product reaches 0.15-0.25 eq / 100g, then stop the reaction to obtain the product system; (3) Add water to the product system, let it stand and separate into layers, remove the lower aqueous phase, add ethanol to the upper organic phase to dilute, and adjust the pH to 6-7. Then remove excess solvent and water to obtain a brownish-black viscous product, namely epoxy-modified phenolic resin.

6. The preparation method according to claim 5, characterized in that, in, The dosage of phenol is 100 parts by mass, the concentration of sodium hydroxide aqueous solution is 15-25 wt%, the dosage is 40-50 parts by mass, the formaldehyde solution is industrial grade methanol aqueous solution, the dosage is 80-100 parts by mass, and the dosage of epichlorohydrin is 120-150 parts by mass.

7. The preparation method according to claim 4, characterized in that, In the hydrophobic organic material, the mass ratio of polyacrylamide resin, potassium dihydrogen phosphate, octadecyltrimethylammonium chloride, and epoxy-modified phenolic resin is 1:1:3:

1.

8. The preparation method according to claim 4, characterized in that, in, The ceramic aggregate has a particle size of less than 5 mm; and / or, the calcium hydroxide content in the calcium carbide slag powder is above 80 wt%, the free water content is below 10 wt%, and the fineness is 60-100 mesh; and / or, the fineness of the zeolite powder is 80-120 mesh, the cation exchange capacity is above 120 mmol / 100g, and the pH value is 7-8; and / or, the specific surface area of ​​the ferrosilicon manganese slag powder is above 400 m² / kg, the sieve residue is below 6 wt%, and the water content is below 1 wt%; and / or, the epoxy value of the epoxy-modified phenolic resin is 0.15-0.25 eq / 100g.

9. The preparation method according to claim 4, characterized in that, The process of obtaining the pretreated phosphogypsum includes: dispersing the phosphogypsum and adding water, then removing surface oil and screening out large impurities, then dispersing the resulting phosphogypsum particles and performing multi-stage washing to remove soluble phosphates, fluorides and other impurities from the phosphogypsum, to obtain washed phosphogypsum; drying the washed phosphogypsum at 100-110℃ to obtain dried phosphogypsum; and ball milling the dried phosphogypsum to 80-120 mesh and passing it through a 100-mesh sieve to obtain the pretreated phosphogypsum.

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