Ecological slope protection material, system and method based on struvite biomineralization technology

Abstract

The invention discloses an ecological slope protection material, system and method based on struvite biomineralization technology.The ecological slope protection material comprises a slope stabilization material and a vegetation matrix, the slope stabilization material is composed of an enzyme-induced phosphate precipitation reaction solution and an enzyme-induced carbonate precipitation reaction solution, and through the synergistic effect of the two biomineralization technologies, the slope stabilization material can be used for slope protection. A biological mineralization reaction occurs in the side slope to generate struvite, magnesium carbonate and other minerals, so that side slope tailing sand reinforcement and heavy metal stabilization are realized, and slow-release nutrition is provided for plant growth. The invention further constructs a multi-layer slope protection system comprising a slope lattice beam, an in-situ remediation area, a slope drainage layer and a slope vegetation layer, and the multi-layer slope protection system is achieved through a construction method combined with a special grouting-sprinkling irrigation device. And finally, integrated safety reinforcement and ecological regreening of the side slope of the heavy metal tailings pond are achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of slope treatment and ecological restoration, and particularly relates to an ecological slope protection material, system and method based on struvite biomineralization technology. BACKGROUND

[0002] Tailings, as the main solid waste in the process of mining and ore dressing, have been stored for a long time, which leads to land resource occupation, excessive heavy metal dissolution, loss of guest soil, soil structure barren, soil and water loss aggravation, and even tailings dam collapse and other geological disaster risks, which seriously threaten the safety of the surrounding ecological system and human living environment. Therefore, ecological restoration of tailings pond is not only a key measure to prevent and control the spread of heavy metal pollution and curb soil and water loss and secondary geological disasters, but also an important way to restore land function and improve regional biodiversity and ecological service value.

[0003] In recent years, biomineralization technology has been widely explored for ecological stabilization and heavy metal stabilization of loose substrates such as tailings due to its advantages of in-situ implementation, small disturbance, and environmental friendliness. Among them, the microorganism / enzyme induced carbonate precipitation technology (MICP / EICP) can effectively cement particles and improve soil strength by generating carbonate cement such as calcite through urease-producing bacterial strains metabolism of urea or exogenous urease catalytic hydrolysis to generate carbonate ions and combine with calcium ions. However, this technology has limitations in practical application: (1) The fixation of heavy metals is mainly based on surface adsorption or coprecipitation, and the carbonate combination state is easy to dissolve in acidic environment (such as acid rain, microbial metabolic acid), which has insufficient long-term stability; (2) The urea hydrolysis process is accompanied by the release of a large amount of ammonia nitrogen, which easily causes secondary environmental pollution, limiting its application in ecologically sensitive areas; (3) The simultaneous stabilization efficiency of multiple heavy metals is low, which is difficult to meet the restoration needs of complex tailings pollution scenarios.

[0004] Compared with the above, the microorganism / enzyme induced phosphate precipitation technology (MIPP / EIPP) can form heavy metal phosphate minerals with extremely low solubility and stable crystal structure by secreting phytase or directly adding phytase to catalyze the hydrolysis of organic phosphorus sources (such as glycerophosphate) to generate phosphate, and then combine with heavy metal ions. However, the existing MIPP / EIPP technology has high cost and low biomineralization efficiency, which leads to poor economic efficiency of engineering application and limited large-scale promotion.

[0005] Therefore, it is urgent to develop a new type of biological stabilization technology with high heavy metal stabilization efficiency, good environmental adaptability, low secondary pollution risk and low cost feasibility, in order to break through the dual constraints of insufficient stability of MICP / EICP and poor economy of MIPP / EIPP, and provide sustainable and popularized technical support for ecological restoration of tailings pond. SUMMARY

[0006] The purpose of this invention is to provide an ecological slope protection material, system, and method based on struvite biomineralization technology, so as to solve at least one of the above-mentioned technical problems.

[0007] To achieve the above objectives, the first aspect of the present invention provides an ecological slope protection material based on struvite biomineralization technology. The ecological slope protection material includes a slope stabilization material and a vegetation substrate. The slope stabilization material is composed of an enzyme-induced phosphate precipitation reaction solution and an enzyme-induced carbonate precipitation reaction solution. The enzyme-induced phosphate precipitation reaction solution includes phytase solution, glycerol phosphate salt, and magnesium salt. The enzyme-induced carbonate precipitation reaction solution includes urease solution, urea, and magnesium salt. The vegetation substrate, by weight percentage, comprises: 45%-65% base substrate, 20%-30% organic amendment, 0.1%-0.3% water-retaining agent, 0.5%-1% fiber material, 10%-20% soil loosening agent, and 0.2%-5% slow-release compound fertilizer. The base substrate is tailings sand treated with the slope stabilization material.

[0008] In the first aspect, the enzyme-induced phosphate precipitation reaction solution is prepared by the following steps: dissolving equal amounts of glycerol phosphate salt and magnesium salt in water to obtain an EIPP gel, and mixing the EIPP gel with the phytase solution to obtain the enzyme-induced phosphate precipitation reaction solution, wherein the volume of the EIPP gel is 90%-99% of the volume of the enzyme-induced phosphate precipitation reaction solution, and the volume of the phytase solution is 1%-10% of the volume of the enzyme-induced phosphate precipitation reaction solution; the enzyme-induced carbonate precipitation reaction solution is prepared by the following steps: dissolving equal amounts of urea and magnesium salt in water to obtain an EICP gel, and mixing the EICP gel with the urease solution to obtain the enzyme-induced carbonate precipitation reaction solution, wherein the volume of the EICP gel is 70%-90% of the volume of the enzyme-induced carbonate precipitation reaction solution, and the volume of the urease solution is 10%-30% of the volume of the enzyme-induced carbonate precipitation reaction solution.

[0009] In the first aspect, the concentration of the enzyme-induced phosphate precipitation reaction solution, based on the concentration of glycerophosphate salt, includes a low-concentration EIPP reaction solution of 0.03-0.1 mol / L and a high-concentration EIPP reaction solution of 0.2-0.3 mol / L; the concentration of the enzyme-induced carbonate precipitation reaction solution, based on the concentration of urea, includes a low-concentration EICP reaction solution of 0.06-0.2 mol / L and a high-concentration EICP reaction solution of 1.0-1.5 mol / L; wherein the high-concentration EIPP reaction solution and the high-concentration EICP reaction solution are used for grouting reinforcement; and the low-concentration EIPP reaction solution and the low-concentration EICP reaction solution are used for sprinkler irrigation repair.

[0010] In the first aspect, the organic amendment includes at least one of compost, humus, peat, and coconut coir; the fibrous material includes at least one of rice straw, wheat straw, corn stalks, and peanut shells; the soil loosening agent includes at least one of bentonite, pumice, and perlite; and the slow-release compound fertilizer includes an organic-inorganic compound fertilizer.

[0011] The second aspect of this invention provides an ecological slope protection system based on struvite biomineralization technology. The system comprises ecological slope protection materials constructed using the struvite biomineralization technology described in the first aspect, used for the safety reinforcement and ecological restoration of heavy metal tailings pond slopes. The system includes: a slope grid beam, formed by grouting and solidifying a high-concentration slope stabilizing material within the slope to form a grid-like reinforcement structure; an in-situ restoration zone, including the slope grid beam and the area enclosed by it, formed by spraying a low-concentration slope stabilizing material across the entire slope surface; a slope drainage layer, laid on the surface of the in-situ restoration zone; and a slope vegetation layer, formed by spraying a mixture of vegetation substrate and plant seeds onto the slope drainage layer.

[0012] In the second aspect, the grid spacing of the slope grid beam is 2-5m, and the cross-sectional width and height of the grid beam are both 0.3-1m; the slope drainage layer is made of gravel or crushed stone with a particle size of 5-20mm, and the thickness of the slope drainage layer is 0.05-0.2m; the thickness of the slope vegetation layer is 0.1-0.3m.

[0013] The third aspect of this invention provides an ecological slope protection method based on struvite biomineralization technology. The method includes constructing the ecological slope protection system based on struvite biomineralization technology described in the second aspect. The method comprises the following steps: in-situ slope treatment using a grouting-spraying device; first, injecting high-concentration EIPP reaction solution and high-concentration EICP reaction solution into pre-set holes on the slope, forming a slope grid beam after curing; then, spraying low-concentration EIPP reaction solution and low-concentration EICP reaction solution onto the entire slope surface, forming an in-situ restoration zone after curing; laying a slope drainage layer with a thickness of 0.05-0.2m on the surface of the cured in-situ restoration zone; and spraying a mixture of vegetation substrate and plant seeds onto the slope drainage layer to form a slope vegetation layer, thus completing the ecological restoration of the slope.

[0014] In the third aspect, the grouting-spraying device includes: a first storage tank for storing EIPP cementing solution or EICP cementing solution; a second storage tank for storing phytase solution or urease solution; an automatic mixing tank, wherein a first flow control valve is installed between the inlet of the automatic mixing tank and the outlet of the first storage tank, and a second flow control valve is installed between the inlet of the automatic mixing tank and the outlet of the second storage tank; a grouting pump connected to the automatic mixing tank; and a plurality of pipes, all of which converge at... The automatic mixing tank has a liquid outlet; several grouting pipes, each of which is connected to a corresponding pipeline, and a grouting shut-off valve is installed at each connection; each grouting pipe has a grouting hole at its end, the diameter of which gradually increases with the distance from the end of the grouting pipe; several sprinkler heads, each of which is connected to a corresponding pipeline, and a sprinkler shut-off valve is installed at each connection; wherein, each pipeline is equipped with a constant pressure valve and a flow meter.

[0015] In the third aspect, the volume ratio of the high-concentration EIPP reaction solution to the high-concentration EICP reaction solution is 1:1, and the concentration ratio of the high-concentration EIPP reaction solution to the high-concentration EICP reaction solution is 1:5; the volume ratio of the low-concentration EIPP reaction solution to the low-concentration EICP reaction solution is 1:1, and the concentration ratio of the low-concentration EIPP reaction solution to the low-concentration EICP reaction solution is 1:2; wherein, after injecting the high-concentration EIPP reaction solution, it is necessary to cure for 12-48 hours before injecting the high-concentration EICP reaction solution; after spraying the low-concentration EIPP reaction solution, it is necessary to cure for 12-48 hours before spraying the low-concentration EICP reaction solution; the high-concentration EIPP reaction solution, the high-concentration EICP reaction solution, the low-concentration EIPP reaction solution, and the low-concentration EICP reaction solution must all be mixed and prepared immediately before injection or spraying.

[0016] In the third aspect, the plant seeds include ryegrass, tall fescue, bermudagrass, alfalfa, and purple acacia, with a sowing rate of 20-50 g / m². 2 .

[0017] Beneficial effects: This invention provides an ecological slope protection material based on struvite biomineralization technology, comprising a slope stabilization material and a vegetation substrate. The slope stabilization material consists of an enzyme-induced phosphate precipitation reaction solution and an enzyme-induced carbonate precipitation reaction solution. Through the synergistic effect of EIPP and EICP biomineralization technologies, urease solution can efficiently catalyze the decomposition of urea to produce carbonate and ammonium ions, while phytase solution catalyzes the hydrolysis of glycerophosphate salts to generate phosphate ions, which combine with magnesium ions in the solution and capture ammonium ions continuously generated during the EICP reaction, thereby forming struvite precipitates with a cementing effect to effectively fill and consolidate the slope pores. At the same time, the magnesium carbonate precipitate generated by the reaction of carbonate and magnesium ions can further enhance the slope's erosion resistance and structural stability. In addition, the vegetation substrate uses tailings sand treated with the slope stabilization material as the base substrate, and is compounded with organic amendments, water-retaining agents, fiber materials, soil loosening agents, and slow-release compound fertilizers to provide the necessary water and fertilizer conditions and root development environment for plant growth. This invention combines two biomineralization technologies, EIPP and EICP, which can both reinforce slopes and stabilize heavy metals by generating mineral cement, and provide slow-release nutrients for plants by generating products such as struvite. At the same time, the specific formula of the vegetation substrate ensures the site conditions and continuous growth of plants on the improved tailings sand, thus achieving the dual effect of slope reinforcement and ecological restoration. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of an ecological slope protection system based on struvite biomineralization technology in this invention; Figure 2 This is a schematic diagram of the slope grid beam in this invention; Figure 3 This is a schematic diagram of the grouting-sprinkler irrigation device in this invention; Figure 4 This is a schematic diagram of the grouting hole positions in an embodiment of the present invention; Figure 5 This is an XRD pattern of the product after tailings sand has been treated with high-concentration and low-concentration slope stabilization materials in this invention. Figure 6 This is an XRD pattern of the product detected after mixing the EIPP reaction solution and the EICP reaction solution in this invention. Figure label: 1. First storage tank; 2. Second storage tank; 3. Automatic mixing tank; 4. First flow control valve; 5. Second flow control valve; 6. Grouting pump; 7. Pipeline; 8. Grouting pipe; 9. Grouting shut-off valve; 10. Grouting hole; 11. Sprinkler nozzle; 12. Sprinkler shut-off valve; 13. Constant pressure valve; 14. Flow meter; L1, slope vegetation layer; L2, slope drainage layer; L3, in-situ restoration zone (including lattice beams); L4, in-situ restoration zone (excluding lattice beams). Detailed Implementation

[0020] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments 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 are within the scope of protection of the present invention.

[0021] Furthermore, in the embodiments of this specification, when a component is described as "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is considered to be "set on" another component, it can be directly set on the other component or there may be an intervening component.

[0022] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0023] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be obtained by purchasing them from the market or by existing methods.

[0024] This invention provides an ecological slope protection material based on struvite biomineralization technology. The ecological slope protection material includes a slope stabilization material and a vegetation substrate. The slope stabilization material is composed of an enzyme-induced phosphate precipitation reaction solution and an enzyme-induced carbonate precipitation reaction solution. The enzyme-induced phosphate precipitation reaction solution includes phytase solution, glycerol phosphate salt, and magnesium salt. The enzyme-induced carbonate precipitation reaction solution includes urease solution, urea, and magnesium salt. The vegetation substrate, by weight percentage, includes: 45%-65% base substrate, 20%-30% organic amendment, 0.1%-0.3% water-retaining agent, 0.5%-1% fiber material, 10%-20% soil loosening agent, and 0.2%-5% slow-release compound fertilizer. The base substrate is tailings sand treated with the slope stabilization material.

[0025] Specifically, this invention provides an ecological slope protection material based on struvite biomineralization technology, comprising a slope stabilization material and a vegetation substrate. The slope stabilization material consists of an enzyme-induced phosphate precipitation reaction solution and an enzyme-induced carbonate precipitation reaction solution. Through the synergistic effect of EIPP and EICP biomineralization technologies, urease solution can efficiently catalyze the decomposition of urea to produce carbonate and ammonium ions, while phytase solution catalyzes the hydrolysis of glycerophosphate salts to generate phosphate ions, which combine with magnesium ions in the solution and capture ammonium ions continuously generated during the EICP reaction, thereby forming struvite precipitates with a cementing effect to effectively fill and consolidate the pores of the slope. At the same time, the magnesium carbonate precipitate generated by the reaction of carbonate and magnesium ions can further enhance the erosion resistance and structural stability of the slope. In addition, the vegetation substrate uses tailings sand treated with the slope stabilization material as the base substrate, and is compounded with organic amendments, water-retaining agents, fiber materials, soil loosening agents, and slow-release compound fertilizers to provide the necessary water and fertilizer conditions and root development environment for plant growth. This invention combines two biomineralization technologies, EIPP and EICP, which can both reinforce slopes and stabilize heavy metals by generating mineral cement, and provide slow-release nutrients for plants by generating products such as struvite. At the same time, the specific formula of the vegetation substrate ensures the site conditions and continuous growth of plants on the improved tailings sand, thus achieving the dual effect of slope reinforcement and ecological restoration.

[0026] In some possible embodiments, the enzyme-induced phosphate precipitation reaction solution is prepared by the following steps: dissolving equal amounts of glycerol phosphate salt and magnesium salt in water to obtain an EIPP gel, and mixing the EIPP gel with the phytase solution to obtain the enzyme-induced phosphate precipitation reaction solution, wherein the volume of the EIPP gel is 90%-99% of the volume of the enzyme-induced phosphate precipitation reaction solution, and the volume of the phytase solution is 1%-10% of the volume of the enzyme-induced phosphate precipitation reaction solution; the enzyme-induced carbonate precipitation reaction solution is prepared by the following steps: dissolving equal amounts of urea and magnesium salt in water to obtain an EICP gel, and mixing the EICP gel with the urease solution to obtain the enzyme-induced carbonate precipitation reaction solution, wherein the volume of the EICP gel is 70%-90% of the volume of the enzyme-induced carbonate precipitation reaction solution, and the volume of the urease solution is 10%-30% of the volume of the enzyme-induced carbonate precipitation reaction solution.

[0027] In this application, by specifying the optimal molar ratio of reactants, the reactants are ensured to fully participate in the reaction, maximizing the precipitation efficiency, avoiding waste or side reactions caused by excessive amounts of certain reactants, and ensuring the reinforcement and stabilization effect.

[0028] It should be noted that the phytase solution in this application can be a commercially available product with an enzyme activity range of 10,000-100,000 U / mL. Here, one unit of phytase activity (U) is defined as the amount of enzyme required to release 1 μmol of phosphorus per minute from a 0.005 M sodium phytate solution under conditions of pH 5.5 and temperature 37°C.

[0029] The urease solution of this application can be prepared independently. The preparation process is as follows: Purchase any one of raw soybean powder, soybean flour, mung bean powder, pea flour, or lentil flour, dissolve it in water to prepare a mixture with a concentration of 100-200 g / L, stir and let it stand for 12-24 hours, then filter it with gauze to remove the residue, and obtain a light yellow crude urease extract. Finally, adjust its activity by adding water to prepare a urease solution with an enzyme activity of 10-30 mM urea / min. In this process, the activity of urease solution was determined by conductivity method. The specific detection method is as follows: 3 mL of the urease solution to be tested was thoroughly mixed with 27 mL of 1.1 mol / L urea solution, and the conductivity increment (ΔE) of the solution was recorded within a specific time (t, in minutes). Combined with the dilution factor of urease solution (m, i.e., total volume / enzyme solution volume = 30 / 3 = 10), the activity U of urease solution per unit volume was calculated using the formula U = 11.11 × ΔE × m / t, and the unit was mM urea / min.

[0030] In some possible embodiments, the concentration of the enzyme-induced phosphate precipitation reaction solution is based on the concentration of glycerophosphate salts, including a low-concentration EIPP reaction solution of 0.03-0.1 mol / L and a high-concentration EIPP reaction solution of 0.2-0.3 mol / L; the concentration of the enzyme-induced carbonate precipitation reaction solution is based on the concentration of urea, including a low-concentration EICP reaction solution of 0.06-0.2 mol / L and a high-concentration EICP reaction solution of 1.0-1.5 mol / L; wherein the high-concentration EIPP reaction solution and the high-concentration EICP reaction solution are used for grouting reinforcement; and the low-concentration EIPP reaction solution and the low-concentration EICP reaction solution are used for sprinkler irrigation repair.

[0031] Specifically, this application sets concentration gradients for different application scenarios. High-concentration solutions are mainly used to form structural lattice beams, providing strong mechanical support; low-concentration solutions are used for large-area surface remediation, stabilizing heavy metals while avoiding severe soil compaction, preserving vegetation pores, and facilitating plant rooting.

[0032] In some possible implementations, the organic amendment includes at least one of compost, humus, peat, and coconut coir; the fibrous material includes at least one of rice straw, wheat straw, corn stalks, and peanut shells; the soil loosening agent includes at least one of bentonite, pumice, and perlite; and the slow-release compound fertilizer includes an organic-inorganic compound fertilizer.

[0033] Specifically, organic amendments and slow-release compound fertilizers provide long-term nutrients; water-retaining agents enhance drought resistance; and fiber materials and soil loosening agents improve substrate structure, prevent compaction and erosion, and create an ideal environment for seed germination and plant growth. This application improves vegetation cover by optimizing the formulation of the vegetation substrate and utilizing the synergistic effect of each component. The slow-release compound fertilizer is an organic-inorganic compound fertilizer, wherein organic matter (on a dry basis): 20%–45%, total nutrients (N+P2O5+K2O): 15%–30%, of which the N:P2O5:K2O range is N: 6%–12%, P2O5: 1%–6%, K2O: 8%–15%.

[0034] Based on a general inventive concept, please refer to... Figures 1-2The second aspect of this invention provides an ecological slope protection system based on struvite biomineralization technology. The system comprises ecological slope protection materials constructed using the struvite biomineralization technology described in the first aspect, used for the safety reinforcement and ecological restoration of heavy metal tailings pond slopes. The system includes: a slope grid beam, formed by grouting and solidifying a high-concentration slope stabilizing material within the slope to form a grid-like reinforcement structure; an in-situ restoration zone, including the slope grid beam and the area enclosed by it, formed by spraying a low-concentration slope stabilizing material across the entire slope surface; a slope drainage layer, laid on the surface of the in-situ restoration zone; and a slope vegetation layer, formed by spraying a mixture of vegetation substrate and plant seeds onto the slope drainage layer.

[0035] Specifically, the present invention provides an ecological slope protection system based on struvite biomineralization technology, which is used to achieve safe reinforcement and ecological synergistic restoration of the slope of heavy metal tailings pond. It is constructed based on the above-mentioned ecological slope protection materials. Its core lies in using biocatalysts such as phytase or urease to induce a controllable precipitation reaction of magnesium ions, phosphate (or carbonate) and ammonium ions in the solution in situ, generating struvite minerals with cementing properties. The specific structure includes: a slope grid beam, which is grouted into the slope with high-concentration slope stabilization material, and rapidly forms a high-strength, grid-like struvite cemented skeleton through enzymatic reaction, significantly improving the overall stability of the slope; an in-situ restoration zone, covering the grid beam and its enclosed area, where the entire slope is treated with low-concentration stabilization material by spraying, which slowly mineralizes under mild conditions to form a dense but permeable struvite cover layer, effectively passivating heavy metals, suppressing dust, and improving the surface soil structure; a slope drainage layer, laid on top of the in-situ restoration zone, to ensure the orderly drainage of rainwater and prevent erosion and water accumulation; and an uppermost slope vegetation layer, which is a mixture of vegetation substrate and plant seeds sprayed onto the surface of the slope drainage layer. With the stable base provided by the struvite mineralization layer and the support of slow-release nutrients (such as phosphorus, nitrogen, and magnesium), it promotes rapid vegetation establishment and growth, achieving long-term ecological function restoration of the slope. The ecological slope protection system provided by this invention organically combines the chemical stabilization effect of biomineralization with ecological restoration, and has multiple functions such as mechanical enhancement, pollutant fixation and green revegetation. It is suitable for the sustainable management of slopes of high-risk heavy metal tailings ponds.

[0036] In conjunction with the second aspect of the present invention, the grid spacing of the slope grid beam is 2-5m, and the cross-sectional width and height of the grid beam are both 0.3-1m; the slope drainage layer is made of gravel or crushed stone with a particle size of 5-20mm, and the thickness of the slope drainage layer is 0.05-0.2m; the thickness of the slope vegetation layer is 0.1-0.3m.

[0037] In this application, the spacing of the lattice beams is controlled at 2-5m, and the cross-sectional width and height are both 0.3-1m. This ensures sufficient anti-sliding and shear support for the tailings dam slope while avoiding excessive hardening that could affect ecological permeability. In the in-situ remediation area enclosed by the lattice beams, a low-concentration stabilizing material is sprayed to form a dense but porous struvite mineralization layer on the slope surface through a slow-release enzymatic reaction. This effectively passivates heavy metal ions and improves the surface physical structure. The slope drainage layer laid on top consists of gravel or crushed stone with a particle size of 5-20 mm and a thickness of 0.05-0.2m. This not only ensures rapid drainage of rainfall and prevents erosion but also provides a good aeration and permeability environment for the underlying mineralization layer. The outermost vegetation layer on the slope is 0.1-0.3 m thick and is formed by spraying a mixture of vegetation substrate and suitable plant seeds. Relying on nutrients such as nitrogen, phosphorus, and magnesium slowly released from struvite, it promotes rapid vegetation germination and root anchoring, further enhancing slope stability and achieving ecological self-sustainability. The overall system achieves a synergistic restoration mechanism integrating "chemical stabilization, hydrological regulation, and ecological reconstruction" through precise control of material concentration, structural scale, and mineralization kinetics.

[0038] Based on a general inventive concept, the third aspect of this invention provides an ecological slope protection method based on struvite biomineralization technology. The method includes constructing the ecological slope protection system based on struvite biomineralization technology described in the second aspect. The method comprises the following steps: in-situ slope treatment using a grouting-spraying device; firstly, injecting high-concentration EIPP reaction solution and high-concentration EICP reaction solution into pre-set holes on the slope, forming a slope grid beam after curing; then spraying low-concentration EIPP reaction solution and low-concentration EICP reaction solution onto the entire slope surface, forming an in-situ restoration zone after curing; laying a slope drainage layer with a thickness of 0.05-0.2m on the surface of the cured in-situ restoration zone; and spraying a mixture of vegetation substrate and plant seeds onto the slope drainage layer to form a slope vegetation layer, thus completing the ecological restoration of the slope.

[0039] Specifically, this invention provides an ecological slope protection method based on struvite biomineralization technology. By synergistically utilizing a dual reaction system of EIPP and EICP, it achieves structural reinforcement and ecological function reconstruction of heavy metal tailings dam slopes. The method relies on an integrated grouting-sprinkler irrigation device for in-situ treatment: First, high-concentration EIPP and EICP reaction solutions are injected into pre-set holes on the slope. Under enzymatic catalysis, these solutions hydrolyze to generate phosphate / ammonium ions or carbonate / ammonium ions, which rapidly combine with magnesium ions to form a high-strength cementitious body primarily composed of struvite supplemented with basic magnesium carbonate and other minerals. After curing, this forms a grid-like slope truss, providing deep anti-sliding and overall stability. Subsequently, low-concentration EIPP and EICP reaction solutions are evenly sprayed across the entire slope. Through slow-release enzymatic reactions, a dense but porous mineralized layer is generated in situ on the surface, forming an in-situ remediation zone with heavy metal passivation, erosion resistance, and water retention capabilities. Based on this, a layer with a thickness of 0.05-0.2 m and a particle size of 5-20 is laid. The slope drainage layer, composed of gravel or crushed stone, effectively guides surface runoff, prevents erosion, and maintains good water and air exchange. Finally, a vegetation substrate rich in organic matter and nutrients is mixed with suitable plant seeds and sprayed onto the drainage layer to form a slope vegetation layer. This vegetation layer not only promotes plant establishment and growth by utilizing the nitrogen, phosphorus, magnesium, and other nutrients slowly released during the mineralization process of struvite, but its root system can also further anchor the surface and enhance erosion resistance, ultimately achieving a long-term ecological slope protection effect through the coupling of multiple mechanisms of "chemical bonding - physical drainage - biological cover".

[0040] It should be further explained that the pre-set hole positions on the slope are distributed along the central axis of the slope grid beam, with the spacing equal to the width of the pre-set grid beam and the hole depth equal to the depth of the grid beam. The total grouting volume of the high-concentration EIPP reaction solution and the high-concentration EICP reaction solution is determined based on the slope porosity, and the relevant calculation formula is: Total grouting volume = π × (width of pre-set grid beam / 2)² × height of pre-set grid beam × porosity × number of holes. The calculation formula for the total spraying volume of the low-concentration EIPP reaction solution and the low-concentration EICP reaction solution is: Total spraying volume = volume of the slope area to be treated × porosity.

[0041] In conjunction with the third aspect of the invention, such as Figure 3As shown, the grouting-spraying device includes: a first storage tank 1 for storing EIPP or EICP cementing solution; a second storage tank 2 for storing phytase or urease solution; an automatic mixing tank 3, wherein a first flow control valve 4 is installed between the inlet of the automatic mixing tank 3 and the outlet of the first storage tank 1, and a second flow control valve 5 is installed between the inlet of the automatic mixing tank 3 and the outlet of the second storage tank 2; a grouting pump 6 connected to the automatic mixing tank 3; and a plurality of pipes 7, all of which converge at the automatic mixing tank. The system includes: an outlet for grouting; several grouting pipes 8, each of which is connected to a corresponding pipe 7, and a grouting shut-off valve 9 installed at each connection; a grouting hole 10 at the end of each grouting pipe 8, the diameter of which gradually increases with the distance from the end of the grouting pipe 8; several sprinkler heads 11, each of which is connected to a corresponding pipe 7, and a sprinkler shut-off valve 12 installed at each connection; and a constant pressure valve 13 and a flow meter 14 installed on each pipe 7.

[0042] Specifically, the grouting-spraying device of this application includes a first storage tank 1 and a second storage tank 2, which are used to independently store stable EIPP cementing solution (containing glycerol phosphate salts and magnesium salts) or EICP cementing solution (containing urea and magnesium salts) and corresponding enzyme solutions (phytase solution or urease solution), respectively, to avoid premature enzyme catalysis during storage. The two solutions are precisely introduced into the automatic mixing tank 3 in a preset ratio through the first flow control valve 4 and the second flow control valve 5, so as to achieve immediate and uniform mixing of cementing solution and enzyme solution before use, ensuring that the reaction starts instantly during injection or spraying, thereby accurately controlling the mineralization initiation time and spatial distribution. The mixed reaction solution is pressurized and transported by the grouting pump 6 to several parallel pipes 7. Each pipe 7 is equipped with a constant pressure valve 13 and a flow meter 14 to maintain stable system pressure and monitor the flow of each branch in real time, ensuring the uniformity and repeatability of construction. The pipeline 7 is connected to two types of functional outlets at its end: one is a grouting pipe 8 with a grouting shut-off valve 9, used for deep injection of high-concentration solutions. The grouting holes 10 at its end are designed to gradually expand along the pipe axis (the hole diameter increases with distance from the end, and the diameter of the grouting holes 10 at the end of the grouting pipe 8 is smaller), effectively balancing the injection pressure and diffusion range of the grout at different depths, promoting uniform nucleation and dense cementation of struvite crystals inside the lattice beam; the other is a sprinkler nozzle 11 with a sprinkler shut-off valve 12, used for uniform surface spraying of low-concentration solutions, forming an in-situ remediation mineralization layer covering the entire slope. The grouting-sprinkler irrigation device provided in this application, through modular flow path control, dynamic proportioning and mixing, and differentiated application processes, achieves precise control of the entire process from deep structural reinforcement to surface ecological restoration, significantly improving the biomineralization efficiency, cementation quality, and ecological restoration effect of struvite, providing efficient and controllable technical support for the safety, stability, and green regeneration of heavy metal tailings dam slopes.

[0043] In conjunction with the third aspect of the present invention, the volume ratio of the high-concentration EIPP reaction solution to the high-concentration EICP reaction solution is 1:1, and the concentration ratio of the high-concentration EIPP reaction solution to the high-concentration EICP reaction solution is 1:5; the volume ratio of the low-concentration EIPP reaction solution to the low-concentration EICP reaction solution is 1:1, and the concentration ratio of the low-concentration EIPP reaction solution to the low-concentration EICP reaction solution is 1:2; wherein, after injecting the high-concentration EIPP reaction solution, it is necessary to cure for 12-48 hours before injecting the high-concentration EICP reaction solution; after spraying the low-concentration EIPP reaction solution, it is necessary to cure for 12-48 hours before spraying the low-concentration EICP reaction solution; the high-concentration EIPP reaction solution, the high-concentration EICP reaction solution, the low-concentration EIPP reaction solution, and the low-concentration EICP reaction solution must all be mixed and prepared immediately before injection or spraying.

[0044] Specifically, this application first applies an EIPP reaction solution to provide phosphate and magnesium ions, forming a pre-set reaction field in the tailings pores. The large amount of ammonium ions generated by the subsequently applied EICP reaction solution can be efficiently captured by the pre-existing phosphate and magnesium ions, rapidly forming a highly stable struvite precipitate. This cleverly avoids the strongly alkaline environment caused by conducting the EICP reaction first, as strong alkali would inhibit the activity of phytase, thus affecting the progress of the EIPP reaction.

[0045] In conjunction with a third aspect of the invention, the plant seeds include ryegrass, tall fescue, bermudagrass, alfalfa, and purple acacia, with a sowing rate of 20-50 g / m². 2 .

[0046] In this application, suitable plant seeds can be selected based on the climate and growth conditions of the slope to be restored. By combining various plant seeds, a three-dimensional vegetation can be quickly formed, effectively preventing soil erosion and further reinforcing the slope through the root system, thereby enhancing the stability and diversity of the ecosystem.

[0047] In summary, the ecological slope protection material provided by this invention, through the stepwise application of specific enzyme-induced phosphate precipitation (EIPP) and enzyme-induced carbonate precipitation (EICP) reaction solutions, synergistically combines two biomineralization technologies. This not only retains the high heavy metal removal rate of EIPP but also releases HPO4 during the EIPP reaction process. 2- and Mg 2+ Capture NH4 continuously generated during the EICP reaction. + This forms struvite, releasing H2O. + This process improves the ammonia nitrogen pollution and alkaline environment caused by EICP (Excessive ICP), while simultaneously forming struvite, an excellent nitrogen and phosphorus fertilizer, providing N and P elements for tailings ecological restoration. Compared with the direct application of N and P fertilizers, the slow-release effect of struvite enhances the sustainability of vegetation growth in tailings and is less susceptible to erosion by rainwater. Furthermore, glycerol, a byproduct of EICP, is fully utilized as a carbon source for plants. In application, low-concentration materials can stabilize heavy metals without causing severe compaction of the tailings, preserving vegetation potential for plant growth. High-concentration mineralization primarily plays a cementing and solidifying role through carbonate and phosphate precipitation, improving the stability of tailings dam slopes. Based on this, a multi-layered slope protection system was constructed, including slope grid beams, in-situ restoration zones, slope drainage layers, and slope vegetation layers. This system was implemented using a specialized grouting-sprinkler irrigation method, ultimately achieving integrated safety reinforcement and ecological restoration of heavy metal tailings dam slopes.

[0048] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0049] This embodiment provides a complete process solution for ecological restoration of tailings dam slopes, as detailed below: 1. Test section conditions and pre-set structural parameters of the ecological slope protection system Selected test section of tailings dam slope: slope area 169m² 2 The tailings sand is square (side length 13m), with a slope of 30° and a porosity of 0.35. Preset structural parameters for the ecological slope protection system: Slope grid beams: The grid beams are spaced 3m apart, with a width of 1m and a height of 0.5m. Therefore, there are a total of 88 pre-set holes on the slope to be repaired. In-situ restoration zone: formed by spraying low-concentration slope stabilization material, with an effective spraying depth of 5m; Slope drainage layer: It is made of gravel or crushed stone with a particle size of 5-20mm and a thickness of 0.1m; Slope vegetation layer: formed by spraying vegetation substrate and plant seeds, with a thickness of 0.2m.

[0050] 2. Calculation of the amount of each structure and corresponding raw material used during the repair process. (1) Calculation of grouting volume for slope grid beam Total grouting volume = π × (width of the pre-set lattice beam / 2)² × height of the pre-set lattice beam × porosity × number of holes. Substituting these parameters, the total grouting volume is calculated to be 12.10 m³. 3 (Approximately 12095.07 L), the reaction solution is prepared according to the requirements of a volume ratio of 1:1 for high-concentration EIPP reaction solution and a concentration ratio of 1:5 for high-concentration EICP reaction solution. The specific amounts of raw materials used are as follows: The high-concentration EIPP reaction solution had a volume of 6.05 m³ (approximately 6047.54 L) and a concentration of 0.25 mol / L. The amount of glycerol phosphate salt and magnesium salt was 1511.88 mol. The glycerol phosphate salt and magnesium salt were dissolved in water to prepare an EIPP cementing solution with a volume of 5745.16 L (95% of the reaction solution volume). The phytase solution had a volume of 302.38 L (5% of the reaction solution volume). The volume of the high-concentration EICP reaction solution is 6.05 m³. 3The concentration of the urea solution was 1.25 mol / L, and the amount of urea was 7559.43 mol and the amount of magnesium salt was 7559.42 mol. The urea and magnesium salt were dissolved in water to prepare an EICP cementing solution with a volume of 4838.03 L (80% of the reaction solution volume). The volume of the urease solution was 1209.51 L (20% of the reaction solution volume).

[0051] (2) Calculation of spraying volume in the in-situ remediation area The total spraying volume = volume of the slope area to be treated × porosity. Substituting the parameters, the total spraying volume is 295.75 m³. 3 (295750.00L), then the reaction solution is prepared according to the requirements of a volume ratio of 1:1 for low-concentration EIPP reaction solution and a concentration ratio of 1:2 for low-concentration EICP reaction solution. The specific amounts of raw materials used are as follows: The volume of the low-concentration EIPP reaction solution is 147.88 m³. 3 (Approximately 147875.00 L), concentration 0.08 mol / L; the amount of glycerol phosphate salt is 11830.00 mol, the amount of magnesium salt is 11830.00 mol, the glycerol phosphate salt and magnesium salt are dissolved in water to prepare an EIPP cementing solution with a volume of 140481.25 L (95% of the reaction solution volume), and the volume of phytase solution is 7393.75 L (5% of the reaction solution volume). The volume of the low-concentration EICP reaction solution is 147.88 m³. 3 The concentration of the solution is 0.16 mol / L. The amount of urea is 23660.00 mol, the amount of magnesium salt is 23660.00 mol, and the amount of urea and magnesium salt is 23660.00 mol. After dissolving the urea and magnesium salt in water, an EICP cementing solution with a volume of 118300.00 L (80% of the reaction solution volume) is prepared. The volume of the urease solution is 29575.00 L (20% of the reaction solution volume).

[0052] (3) Calculation of the amount of crushed stone used in the slope drainage layer The slope drainage layer is 0.10m thick and covers an area of ​​169m². 2 The volume of the slope drainage layer is 16.90 m³. 3 That is, the amount of crushed stone used in the slope drainage layer is 16.90m³. 3 .

[0053] (4) Calculation of the amount of vegetation layer used on the slope The thickness of the slope vegetation layer is 0.2m, and the paving area is 169m². 2 The vegetative substrate and plant seeds are mixed, with the plant seeds being sown at a rate of 30 g / m². 2: The vegetation substrate comprises, by weight percentage: 57% base substrate (tailings sand treated stepwise with low-concentration EIPP reaction solution and low-concentration EICP reaction solution), 25% organic amendment, 0.2% water-retaining agent, 0.8% fiber material, 15% soil loosening agent, and 2% organic-inorganic compound fertilizer (N-P2O5-K2O=10-2-12); The plant seeds, by weight percentage, consist of: 50% ryegrass, 15% tall fescue, 15% bermudagrass, 10% alfalfa and 10% purple acacia.

[0054] 3. Implementation steps for ecological restoration Assemble the grouting-sprinkler system provided above in situ on the slope to be repaired, and insert its grouting pipes into the slope according to the preset hole positions for constant pressure seepage grouting. Figure 4 As shown, the grouting pressure is 0.1-0.5 MPa. The grouting stop valve is opened, and the sprinkler stop valve is closed. First, 6047.54 L of high-concentration EIPP reaction solution is injected and cured for 12-48 hours. Then, another 6047.54 L of high-concentration EICP reaction solution is injected and cured to form a slope grid beam. The grouting stop valve is closed, and the sprinkler stop valve is opened. First, 147875.00 L of low-concentration EIPP reaction solution is sprayed and cured for 12-48 hours. Then, another 147875.00 L of low-concentration EICP reaction solution is sprayed and cured to form an in-situ repair zone. A 16.90 m thick layer is laid on the surface of the oxidized in-situ repair zone. 3 The crushed stone forms a drainage layer on the slope; then the mixed vegetation substrate and plant seeds are sprayed onto the drainage layer to form a vegetation layer on the slope. The slope can be watered and maintained by a grouting-sprinkler irrigation device to keep the vegetation layer at a suitable moisture level until the plant seeds germinate and enter a stable growth period, thus completing the ecological restoration of the tailings dam slope.

[0055] The tailings dam slopes repaired according to the above embodiments were monitored, and the results are shown in Table 1: Table 1 Monitoring Results Note: The control group consisted of plant seeds sprayed only on the slope of the tailings dam, with a consolidation stress of 0 as tested by direct shear test and a shear rate of 1 mm / min.

[0056] In addition, this application also conducted XRD analysis on the products of tailings sand treated with high-concentration and low-concentration slope stabilization materials. Solution experiments were also conducted on both treatment methods, i.e., without the addition of tailings sand, only the EIPP and EICP reaction solutions were mixed, with the reaction time the same as the tailings sand group. The results showed the presence of magnesium carbonate, magnesium hydrogen phosphate, and magnesium ammonium phosphate in both cases. Figures 5-6As shown, the feasibility of this method is demonstrated.

[0057] In summary, compared with the prior art, the present invention has the following advantages: (1) To address the issue of ammonia release due to urea decomposition during EICP, this invention introduces EIPP technology to convert ammonia nitrogen into struvite precipitate, thereby reducing ammonia pollution and converting nitrogen resources into slow-release fertilizer usable by plants. Simultaneously, byproducts such as glycerol further improve the soil, promote vegetation recovery, and create a virtuous cycle in the environment. The stepwise method of EIPP followed by EICP avoids interference from excessive alkalinity caused by EICP, resulting in good heavy metal stability. EIPP first provides phosphate and Mg... 2+ Magnesium hydrogen phosphate, along with other magnesium phosphates, captures ammonia nitrogen during subsequent EICP production, forming struvite and releasing H2O. + It buffers alkalinity.

[0058] (2) This invention uses a special vegetation substrate containing ammonia nitrogen, struvite, glycerol and compound fertilizer, combined with a seed formula that integrates grass and shrubs, to provide plants with comprehensive nutrition and a foundation for growth, thereby achieving rapid and continuous ecological revegetation of slopes. The fiber material ensures the stability of the surface layer in the early stage, while the plant roots provide long-term soil stabilization, enhancing the slope's resistance to erosion and overall durability.

[0059] (3) The present invention forms a slope grid beam by constant pressure infiltration grouting to achieve slope bonding and load-bearing reinforcement; then spray low concentration repair agent to form an in-situ repair zone. The grid gap area retains the suitability for vegetation, is rich in nutrients, and is conducive to the long-term downward infiltration of the roots of Amorpha fruticosa, which can grow beyond the vegetation layer and drainage layer to a deeper depth, and finally form a root-soil composite slope long-term reinforcement system.

[0060] (4) This invention achieves the triple goals of slope mechanical reinforcement, heavy metal ion stabilization, and soil ecological restoration in one go. The struvite generated by the reaction is a slow-release fertilizer, and the byproduct glycerol is a carbon source, realizing in-situ and green treatment of tailings. By first constructing a grid beam and then strengthening the root system, a reliable structural system is formed, which anchors the grid beam, stabilizes the surface layer for a long time, and stabilizes the deep layer in the later stage. Combined with the drainage layer, the stability of the slope is ensured under the erosion of a large amount of rainwater.

[0061] (5) The enzyme-driven reaction in this invention has controllable kinetic characteristics and can provide a suitable reaction buffer period, so that the treatment liquid can achieve more uniform transmission and penetration in the complex pore network of loose sediment tailings. This effectively avoids the problem of local pore blockage caused by near-field instantaneous precipitation in traditional rapid gelation systems, thereby ensuring the overall uniformity and permeability of the solidified body.

[0062] (6) Compared with traditional cement-based materials or geopolymers, which require high-pressure pumping during in-situ injection and are prone to causing disturbance to the tailings structure, the method provided by this invention can be implemented under low-pressure conditions, with mild reaction and small volume change, significantly reducing the disturbance to the original tailings structure during construction. It is more suitable for in-situ reinforcement of loose tailings sites that are sensitive to disturbance, and has both environmental friendliness and engineering operability.

[0063] Finally, it should be noted that the above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. All should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0064] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. An ecological slope protection material based on struvite biomineralization technology, characterized in that, The ecological slope protection materials include slope stabilization materials and vegetation substrates; The slope stabilization material is composed of an enzyme-induced phosphate precipitation reaction solution and an enzyme-induced carbonate precipitation reaction solution. The enzyme-induced phosphate precipitation reaction solution includes phytase solution, glycerol phosphate salt, and magnesium salt; The enzyme-induced carbonate precipitation reaction solution includes urease solution, urea, and magnesium salt; The vegetative substrate comprises, by weight percentage: 45%-65% base substrate, 20%-30% organic amendment, 0.1%-0.3% water-retaining agent, 0.5%-1% fiber material, 10%-20% soil loosening agent, and 0.2%-5% slow-release compound fertilizer; The basic matrix is ​​tailings sand that has been treated with slope stabilization materials.

2. The ecological slope protection material based on struvite biomineralization technology according to claim 1, characterized in that, The enzyme-induced phosphate precipitation reaction solution is prepared by the following steps: dissolving equal amounts of glycerol phosphate salt and magnesium salt in water to obtain an EIPP cementing solution, and mixing the EIPP cementing solution with the phytase solution to obtain the enzyme-induced phosphate precipitation reaction solution, wherein the volume of the EIPP cementing solution is 90%-99% of the volume of the enzyme-induced phosphate precipitation reaction solution, and the volume of the phytase solution is 1%-10% of the volume of the enzyme-induced phosphate precipitation reaction solution; The enzyme-induced carbonate precipitation reaction solution is prepared by the following steps: dissolving equal amounts of urea and magnesium salt in water to obtain an EICP cementing solution, and mixing the EICP cementing solution with the urease solution to obtain the enzyme-induced carbonate precipitation reaction solution, wherein the volume of the EICP cementing solution is 70%-90% of the volume of the enzyme-induced carbonate precipitation reaction solution, and the volume of the urease solution is 10%-30% of the volume of the enzyme-induced carbonate precipitation reaction solution.

3. The ecological slope protection material based on struvite biomineralization technology according to claim 1, characterized in that, The concentration of the enzyme-induced phosphate precipitation reaction solution is based on the concentration of glycerophosphate salt, including a low-concentration EIPP reaction solution of 0.03-0.1 mol / L and a high-concentration EIPP reaction solution of 0.2-0.3 mol / L; the concentration of the enzyme-induced carbonate precipitation reaction solution is based on the concentration of urea, including a low-concentration EICP reaction solution of 0.06-0.2 mol / L and a high-concentration EICP reaction solution of 1.0-1.5 mol / L. The high-concentration EIPP reaction solution and the high-concentration EICP reaction solution are used for grouting reinforcement; the low-concentration EIPP reaction solution and the low-concentration EICP reaction solution are used for sprinkler irrigation repair.

4. The ecological slope protection material based on struvite biomineralization technology according to claim 1, characterized in that, The organic amendment includes at least one of compost, humus, peat, and coconut coir; the fibrous material includes at least one of rice straw, wheat straw, corn stalks, and peanut shells; the soil loosening agent includes at least one of bentonite, pumice, and perlite; and the slow-release compound fertilizer includes an organic-inorganic compound fertilizer.

5. An ecological slope protection system based on struvite biomineralization technology, characterized in that, The system comprises an ecological slope protection material based on struvite biomineralization technology as described in any one of claims 1-4, used for the safety reinforcement and ecological restoration of heavy metal tailings dam slopes, and the system includes: Slope grid beams are formed by grouting high-concentration slope stabilization materials into a grid-like reinforcement structure within the slope. The in-situ remediation zone includes the slope grid beam and the area enclosed by the slope grid beam. The in-situ remediation zone is formed by spraying low-concentration slope stabilization material onto the entire slope surface. A slope drainage layer is laid on the surface of the in-situ remediation area; The slope vegetation layer is formed by spraying a mixture of vegetation substrate and plant seeds onto the slope drainage layer.

6. The ecological slope protection system based on struvite biomineralization technology according to claim 5, characterized in that, The grid spacing of the slope grid beam is 2-5m, and the cross-sectional width and height of the grid beam are both 0.3-1m; The slope drainage layer is made of gravel or crushed stone with a particle size of 5-20mm, and the thickness of the slope drainage layer is 0.05-0.2m. The thickness of the slope vegetation layer is 0.1-0.3m.

7. An ecological slope protection method based on struvite biomineralization technology, characterized in that, The method includes constructing the ecological slope protection system based on struvite biomineralization technology as described in claim 5 or 6, and the method includes the following steps: In-situ slope treatment is carried out using a grouting-spraying device. First, high-concentration EIPP reaction solution and high-concentration EICP reaction solution are injected into the pre-set holes on the slope. After curing, a grid beam is formed on the slope surface. Then, low-concentration EIPP reaction solution and low-concentration EICP reaction solution are sprayed on the entire slope surface. After curing, an in-situ repair area is formed. A 0.05-0.2m thick slope drainage layer is laid on the surface of the in-situ repair area after maintenance is completed; The mixture of vegetation substrate and plant seeds is sprayed onto the drainage layer of the slope to form a vegetation layer and complete the ecological restoration of the slope.

8. The ecological slope protection method based on struvite biomineralization technology according to claim 7, characterized in that, The grouting-spraying device includes: The first storage tank is used to store EIPP cementing solution or EICP cementing solution; The second storage tank is used to store phytase solution or urease solution; An automatic mixing tank, wherein a first flow control valve is installed between the inlet of the automatic mixing tank and the outlet of the first storage tank, and a second flow control valve is installed between the inlet of the automatic mixing tank and the outlet of the second storage tank. The grouting pump is connected to the automatic mixing tank; Several pipes converge at the outlet of the automatic mixing tank; A plurality of grouting pipes are provided, each of which is connected to a corresponding pipe and a grouting shut-off valve is installed at each connection point; each of the grouting pipes has a grouting hole at its end, the diameter of which gradually increases with the distance from the end of the grouting pipe. A plurality of irrigation nozzles, each of which is connected to a corresponding pipe, and an irrigation shut-off valve is installed at each connection point; Each of the aforementioned pipes is equipped with a constant pressure valve and a flow meter.

9. The ecological slope protection method based on struvite biomineralization technology according to claim 7, characterized in that, The volume ratio of the high-concentration EIPP reaction solution to the high-concentration EICP reaction solution is 1:1, and the concentration ratio of the high-concentration EIPP reaction solution to the high-concentration EICP reaction solution is 1:

5. The volume ratio of the low-concentration EIPP reaction solution to the low-concentration EICP reaction solution is 1:1, and the concentration ratio of the low-concentration EIPP reaction solution to the low-concentration EICP reaction solution is 1:

2. Specifically, after injecting the high-concentration EIPP reaction solution, it is necessary to cure for 12-48 hours before injecting the high-concentration EICP reaction solution; after spraying the low-concentration EIPP reaction solution, it is necessary to cure for 12-48 hours before spraying the low-concentration EICP reaction solution; the high-concentration EIPP reaction solution, the high-concentration EICP reaction solution, the low-concentration EIPP reaction solution, and the low-concentration EICP reaction solution must all be mixed and prepared immediately before injection or spraying.

10. The ecological slope protection method based on struvite biomineralization technology according to claim 7, characterized in that, The plant seeds include ryegrass, tall fescue, bermudagrass, alfalfa, and purple acacia, with a sowing rate of 20-50 g / m². 2 .

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