A micro-ecological regulation and restoration method based on autocatalytic acidification control in mining areas

Abstract

This invention discloses a micro-ecological regulation and restoration method based on the autocatalytic acidification control of mining areas. The method includes the following steps: S1 source acid suppression and mineral transformation; S2 heavy metal fixation and mineral stabilization; and S3 micro-ecological reconstruction and ecological restoration. This invention utilizes in-situ iron-sulfur minerals as catalysts to activate added persulfate, generating free radicals. Then, by increasing the release of slow-release alkali sources, a lattice reconstruction reaction occurs, achieving stability. Furthermore, it introduces or enriches native extracellular electroactive microorganisms into the stable system and provides a slow-release carbon source, allowing them to compete with residual acidophilic microorganisms, resulting in antagonistic inhibition. This promotes the establishment and growth of acid-tolerant pioneer plants, achieving a low-consumption, long-lasting, and autonomously guided ecological restoration effect.

Description

Technical Field

[0001] This invention relates to the field of mine soil environment management and ecological restoration technology, and in particular to a micro-ecological regulation and restoration method based on the self-catalytic acidification control of mining areas. Background Technology

[0002] Mining area acidification, especially soil acidification caused by the oxidation of sulfide minerals and its associated heavy metal pollution, has become a global environmental problem. Currently, the mainstream remediation technology is still mainly based on end-of-pipe chemical neutralization, such as adding lime. Although this method can quickly raise the soil pH, it has significant drawbacks: First, it cannot inactivate acidophilic oxidizing microorganisms that cause acidification (such as *Thiobacillus ferrooxidans*), failing to block the acidification process at its source, and the acid source persists; second, it is difficult to effectively fix heavy metals, which still have strong mobility and pose a risk of continuous release; third, drastic changes in the chemical environment can easily damage the soil micro-ecosystem, leading to barren land after remediation, difficulty in natural vegetation establishment, and difficulty in restoring ecological functions.

[0003] In recent years, advanced oxidation processes based on persulfate have been studied for the degradation of organic pollutants due to their ability to generate strong oxidizing free radicals. However, this technology has not yet been applied to the inhibition of acidophilic microorganisms and the remediation of heavy metals in acidified mining areas. Furthermore, its practical application faces challenges such as inconsistent treatment efficiency in complex geological matrices and the potential for indiscriminate attack on native beneficial microbial communities. More critically, most existing technologies treat "pollution control" and "ecological restoration" as two separate stages, lacking an integrated technical solution that organically couples multiple processes—including "eliminating acid-producing bacteria at the source—simultaneously passivating heavy metals—in-situ generation of stable minerals to fix heavy metals—targeted construction of healthy soil habitats—driving vegetation restoration"—to form a self-driven remediation cycle.

[0004] Therefore, developing an in-situ remediation technology that can fully utilize the mineral resources and energy of the mining area to achieve low-consumption, long-term, and autonomously guided ecological restoration has significant theoretical value and practical urgency. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of current technologies for restoring acidified mines, this invention provides a micro-ecological regulation and restoration method based on the self-catalytic acidification control of the mining area, which can achieve low consumption, long-term effect, and autonomous guidance of ecological restoration.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] A micro-ecological regulation and restoration method based on the control of autocatalytic acidification in mining areas, comprising the following steps:

[0008] S1. Source Suppression of Acidity and Mineral Transformation: In acidified mining areas containing iron-sulfur minerals, persulfate is added to generate sulfate radicals and hydroxyl radicals, which inactivate acidophilic oxidizing microorganisms, oxidize and passivate the surface of iron-sulfur minerals, and generate amorphous secondary mineral phases including ferric hydroxysulfate, thereby inhibiting soil acidification and acidic mine water from the source.

[0009] S2. Fixing heavy metals and stabilizing minerals: The pH of the mine soil system is gradually increased to 5.5-7.5 through slow-release alkali source. Under the action of monovalent cation slow-release minerals, the amorphous ferric sulfate secondary mineral phase generated in step S1 undergoes lattice reconstruction and is transformed into structurally stable jaundice or jaundice crystal minerals. The phase transition fixes the heavy metal ions in the solution into the mineral lattice through isomorphous substitution or adsorption, achieving long-term stability.

[0010] S3. Microecological Reconstruction and Ecological Restoration: Introducing or enriching native extracellular electroactive microorganisms into the system treated in steps S1 and S2, and stimulating their metabolic activity by providing a slow-release carbon source or applying a micro-electric field; the extracellular electroactive microorganisms compete with the residual acidophilic microorganisms through extracellular electron transfer, producing antagonistic inhibition, while the metabolites secreted by the extracellular electroactive microorganisms promote the colonization and growth of acid-tolerant pioneer plants, thereby reconstructing a healthy microecology.

[0011] According to one aspect of the present invention, the iron-sulfur minerals present in situ in S1 are pyrite, pyrrhotite, or sulfur-containing tailings.

[0012] According to one aspect of the present invention, the persulfate added in S1 is permonosulfate or perdisulfate.

[0013] According to one aspect of the present invention, the amount of persulfate added is 1-8 millimoles of persulfate per kilogram of contaminated soil or 1-8 millimoles of persulfate per cubic meter of acidic mine wastewater.

[0014] According to one aspect of the present invention, in step S1, before and after adding persulfate for reaction, the treated area is tilled or stirred to a depth of 30-60 cm to ensure that the agent and minerals are in full contact, and the reaction time is not less than 72 hours.

[0015] According to one aspect of the invention, the monovalent cation of S2 is a slow-release potassium salt, sodium salt, or ammonium salt.

[0016] According to one aspect of the invention, the slow-release potassium, sodium, and ammonium salts include potassium feldspar, biotite, potash, and sodium sulfate.

[0017] According to one aspect of the present invention, the slow-release alkali source of S2 is a mineral with a long-lasting slow-release effect.

[0018] According to one aspect of the invention, the minerals having a long-lasting sustained-release effect include dolomite, limestone, and modified minerals thereof.

[0019] According to one aspect of the present invention, the heavy metal ions in the solution in S2 are Cu. 2+ Pb 2+ Zn 2+ Cd 2+ .

[0020] According to one aspect of the invention, the extracellular electroactive microorganisms in S3 include one or more of the following selected from *Geobacillus thioreductoides*, *Shewanella oneneidae*, and *Pseudomonas aeruginosa*, which are screened and domesticated from the mining area.

[0021] According to one aspect of the present invention, the slow-release carbon source in S3 is sodium lactate, sodium acetate or straw biochar, and the amount of the slow-release carbon source added is 0.5%-2% of the soil mass.

[0022] According to one aspect of the present invention, the acid-resistant pioneer plant in S3 is one or more combinations of Miscanthus sinensis, Vetiver, Reed, and Centipede Grass.

[0023] Advantages of this invention: The above technical solution achieves the following effects:

[0024] (1) Eradicating pollution sources and synergistic transformation: Creatively utilizing iron-sulfur minerals from pollution sources as catalysts to drive advanced oxidation processes, while efficiently inactivating acidophilic and free microorganisms colonizing iron-sulfur mineral bodies and cutting off the source of biological acidification, the acid-producing mineral precursors are simultaneously transformed into secondary mineral precursors (amorphous ferric hydroxysulfate) with the potential to fix heavy metals, realizing "waste treatment" and in-situ resource transformation of pollutants, and synergistically controlling the risk of acidification and heavy metal migration from the source;

[0025] (2) Long-term stability and self-sustaining microenvironment: The synergistic effect of slow-release alkali source and slow-release monovalent cationic minerals drives the formation of potassium ferric sulfate and other mineral phases into stable mineral phases under neutral to weakly acidic conditions. This process not only seals heavy metals for a long time through lattice fixation, but the stable mineral phase itself has good pH buffering capacity, which can maintain the neutral microenvironment of the remediated soil for a long time, effectively preventing the acidification rebound phenomenon common in the traditional lime method, and achieving long-term stability;

[0026] (3) Targeted ecological driving and rapid soil habitat construction: The introduced extracellular electroactive microorganisms act as ecological engineers. On the one hand, they competitively inhibit residual acidophilic bacteria through extracellular electron transfer. On the other hand, the abundant extracellular polymers (EPS) secreted by these microorganisms serve as natural and environmentally friendly soil cementing agents, which can rapidly and effectively promote the formation of water-stable soil aggregates. This fundamentally improves the physical structure problems of compaction and poor aeration and permeability that are common in acidified mining areas, creating an excellent growth space for plant roots, which cannot be achieved by simple chemical remediation.

[0027] (4) Formation of a complete ecological restoration closed loop: A complete technological closed loop of mutual promotion has been formed, which involves inactivating acidophilic microorganisms at the source (eliminating biological acid sources) → chemically transforming and passivating mineral acid sources and simultaneously fixing heavy metals (eliminating chemical toxicity) → introducing beneficial functional microorganisms (starting the ecological engine and improving soil physical structure) → supporting the establishment and growth of pioneer plants (achieving vegetation cover and ecological functions). This closed loop ultimately promotes the natural evolution of the damaged mining area ecosystem towards a healthy, stable, and self-sustaining direction, realizing a leap from simple pollution control to overall ecological restoration. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying 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.

[0029] Figure 1 This is a schematic diagram of the process of a micro-ecological regulation and restoration method based on the autocatalytic acidification control of mining areas as described in this invention.

[0030] Figure 2 This is a schematic diagram showing the number of acidophilic microorganisms before and after treatment in Example 1 of the present invention;

[0031] Figure 3 The XRD patterns of pyrite before and after treatment in Example 1 of the present invention are shown below.

[0032] Figure 4 The images show the FTIR spectra before and after treatment in Example 1 of this invention.

[0033] Figure 5 This is a schematic diagram of the pH during the treatment process in Embodiment 1 of the present invention;

[0034] Figure 6 This is a scanning electron microscope image showing the changes in surface morphology and elemental composition of pyrite before treatment in Example 1 of the present invention;

[0035] Figure 7This is a scanning electron microscope image showing the changes in surface morphology and elemental composition of pyrite after treatment in Example 1 of the present invention;

[0036] Figure 8 This is a schematic diagram showing the content of water-stable aggregates in the soil before and after treatment in Example 1 of the present invention;

[0037] Figure 9 This is a schematic diagram of the microbial composition before treatment in Example 1 of the present invention;

[0038] Figure 10 This is a schematic diagram of the microbial composition after treatment in Example 1 of the present invention;

[0039] Figure 11 This is a schematic diagram showing the leaching concentration of arsenic before and after treatment according to TCLP in Example 2 of the present invention;

[0040] Figure 12 The images show the XRD patterns of pyrite mineral crystal structures in the oxygen environment of the sedimentation pond before reaction and the XRD patterns of pyrite mineral crystal structures in the oxygen environment at different soil depths in the sedimentation pond after reaction, according to Example 2 of the present invention.

[0041] Figure 13 This is the EDX surface energy spectrum of pyrite mineral crystals after the reaction in Example 2 of the present invention;

[0042] Figure 14 This is the EDX surface energy spectrum of ore from the early stage of the reaction in Example 3 of the present invention;

[0043] Figure 15 This is the EDX surface energy spectrum of the ore in the mining area during the later stage of the reaction in Example 3 of the present invention;

[0044] Figure 16 This is a schematic diagram showing the heavy metal content of waste rock, the amount of leaching before remediation, and the amount of leaching after remediation in Example 3 of the present invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] A micro-ecological regulation and restoration method based on the control of autocatalytic acidification in mining areas, including, for example Figure 1 The steps shown are as follows:

[0047] S1. Source Suppression of Acidity and Mineral Transformation: In acidified mining areas containing iron-sulfur minerals, persulfate is added to generate sulfate radicals and hydroxyl radicals, which inactivate acidophilic oxidizing microorganisms, oxidize and passivate the surface of iron-sulfur minerals, and generate amorphous secondary mineral phases including ferric hydroxysulfate, thereby inhibiting soil acidification and acidic mine water bodies from the source.

[0048] The persulfate is preferably a permonosulfate or a perdisulfate, such as sodium perdisulfate.

[0049] The dosage of persulfate is determined based on the degree of soil acidification and the number of microorganisms in the mine, and is preferably 5-15 millimoles per kilogram of contaminated soil.

[0050] The inactivated acidophilic oxidizing microorganisms include: Acidobacterium ferrooxidans, Leptospira ferrooxidans, and Thiobacterium thiooxidans.

[0051] The in-situ iron-sulfur minerals are pyrite, pyrrhotite, or pyrite tailings, which are widely found in the mining area.

[0052] The iron-sulfur minerals include pyrite, etc. The surface of the iron-sulfur minerals is oxidized and passivated to generate secondary mineral phases mainly composed of amorphous ferric hydroxysulfate / ferric hydroxyoxide such as Schieleite and ferrous hydride, which inhibits further oxidation and acid production of sulfide minerals from the source.

[0053] Before and after adding persulfate, the treated area can be tilled or stirred to a depth of 30-60 cm to increase the contact area between the agent and the minerals. The reaction time should be no less than 72 hours to ensure a full oxidation reaction.

[0054] S2. Fixing heavy metals and stabilizing minerals: By slowly releasing an alkaline source, the pH of the mine soil system is gradually increased to a weakly acidic to near-neutral range of 5.5-7.5. Under the action of monovalent cation-releasing minerals, the amorphous ferric sulfate secondary mineral phase generated in step S1 undergoes lattice reconstruction and is transformed into structurally stable jaundice or jaundice crystal minerals. This phase transition fixes the heavy metal ions in the solution into the mineral lattice through isomorphous substitution or adsorption, achieving long-term stability.

[0055] The slow-release alkali source is a mineral with a long-lasting slow-release effect, including dolomite, limestone, and their modified products. The modified products are obtained through calcination and grinding. The particle size of the slow-release alkali source is preferably 60-200 mesh, and the application rate is 1%-5% of the soil mass, ensuring that heavy metals effectively enter the stable mineral lattice during a slow pH rise.

[0056] The monovalent cations are derived from potassium, sodium, and ammonium-containing silicate or sulfate minerals with slow-release properties, including potassium feldspar, biotite, potash, and sodium magnesium sulfate.

[0057] The amount of exogenous replenishment of the monovalent cation is based on the estimated total iron (Fe) in the system. 3+ Based on the molar amount, control the molar ratio (M) of monovalent cations to total iron. + / Fe 3+ The ratio should be between 0.5 and 0.8:1 to ensure that there are sufficient but not excessive cations to drive the formation of crystalline minerals such as jaundice and iron oxide.

[0058] The phase transition process can efficiently capture and fix Cu. 2+ Pb 2+ Zn 2+ Cd 2+ Heavy metal ions.

[0059] The isomorphic substitution, such as Cu 2+ Fe replacement 3+ It is fixed inside the mineral lattice.

[0060] The mineral stabilization process requires a sufficient settling and aging time of no less than 14 days after pH adjustment to promote the full growth and maturation of crystalline minerals such as potassium ferric sulfate and ferric sulfate, and to obtain optimal stability.

[0061] S3. Microecological Reconstruction and Ecological Restoration: Microecological reconstruction and ecological restoration: Introducing or enriching native extracellular electroactive microorganisms into the system treated in steps S1 and S2, and stimulating their metabolic activity by providing a slow-release carbon source or applying a micro-electric field; the extracellular electroactive microorganisms compete with residual acidophilic microorganisms through extracellular electron transfer, producing antagonistic inhibition, while the metabolites secreted by the extracellular electroactive microorganisms promote the colonization and growth of acid-tolerant pioneer plants, thereby rebuilding a healthy microecology.

[0062] The extracellular electroactive microorganisms are preferably functional strains screened and domesticated from the local environment of the target mining area, such as *Geotrichum thioreductoides* which has the ability to directly transfer extracellular electrons; *Schizophyllum moniliforme* which has multiple extracellular electron transfer pathways; and *Pseudomonas aeruginosa* which can both generate electricity and secrete abundant extracellular polymers.

[0063] The extracellular electroactive microorganisms can be used alone or in combination.

[0064] The metabolic activities of these extracellular electroactive microorganisms can produce polysaccharides, proteins, and humic substances, which are key cementing agents for the formation of soil aggregates. They can effectively promote the formation of soil aggregate structure and build a healthy soil matrix.

[0065] The preferred inoculum size of the extracellular electroactive microorganisms is 10. 6 -10 8 CFU / Granary Mine Soil.

[0066] The slow-release carbon source is a combination of small-molecule organic acids such as straw, biochar, and sodium acetate.

[0067] The slow-release carbon source can be efficiently utilized by electroactive microorganisms.

[0068] The amount of the slow-release carbon source added is preferably 0.5%-2% of the soil mass.

[0069] The metabolites of these extracellular electroactive microorganisms, such as polysaccharides and proteins, act as natural bio-cementing agents, effectively promoting the formation of water-stable aggregates in the soil and significantly improving the soil's physical structure, water retention, and aeration.

[0070] The acid-resistant pioneer plants include Miscanthus sinensis, Vetiver, Reed, and Centipede Grass, which are selected and combined according to the main heavy metal pollutants in the mining area.

[0071] The acid-tolerant pioneer plant and the metabolic products of the extracellular electroactive microorganisms form a stable growth-promoting system.

[0072] Example 1

[0073] Copper-lead-zinc polymetallic tailings dam acidification soil remediation

[0074] The tailings pond is severely acidified, with an initial pH of 3.2. It is rich in pyrite and exhibits significant heavy metal contamination. The available copper, zinc, and lead content in the tailings pond soil is 154.7 mg / kg, 289.5 mg / kg, and 94.8 mg / kg, respectively. The soil structure in the mining area is completely destroyed, such as... Figure 6 As shown, it is gravelly, without aggregates, and devoid of vegetation. Figure 9 The acidophilic oxidizing microorganisms shown are mainly *Acidithiobacillus ferrooxidans*, with a number as high as 5.6 × 10⁻⁶. 6 CFU / g.

[0075] Use a large rotary tiller to perform two deep tillages on tailings at a depth of 0-40 cm to ensure the soil layer is loose.

[0076] At a dose of 10 mmol / kg, potassium persulfate compound salt powder was evenly spread on the surface of acidified soil in a copper-lead-zinc polymetallic tailings pond, and then lightly mixed to a depth of 20 cm with a disc rake.

[0077] The soil moisture content was maintained at 25% using a spray system, and the reaction lasted for 96 hours. Figure 4 As shown, pyrite in tailings catalyzes the production of potassium persulfate to form SO4. - and •OH.

[0078] After the reaction, the soil pH rose slightly to 3.5. Microbial plate counting showed an inactivation rate of >99.89% for acidophilic oxidizing bacteria. Figure 3As shown, the X-ray diffraction (XRD) spectrum of the sample indicates that the characteristic peaks of pyrite are weakened, and amorphous ferric hydroxysulfate is generated.

[0079] Apply 180-mesh dolomite powder at a ratio of 4% of the soil mass as a slow-release alkali source. (According to K...) + / Fe 3+ Finely ground potassium feldspar powder (200 mesh) was incorporated at a molar ratio of 0.7:1 as a slow-release source of monovalent potassium ions.

[0080] By maintaining the soil under natural conditions, the pH will be steadily and slowly raised to 6.8 over 60 days through the slow dissolution of dolomite and potassium feldspar. Avoid using strong alkaline agents such as quicklime to prevent localized excessively high pH levels.

[0081] After adjusting the pH, allow the mixture to stand for 28 days. Samples were then taken for XRD and scanning electron microscopy analysis, such as... Figure 7 As shown, obvious and well-crystallized jaundice alum crystals are visible, typically in the form of small plates or pseudo-cubic shapes.

[0082] The *Pseudomonas aeruginosa* PA-Z1 and *Shewanella onenei* strains selected locally were inoculated using a 1:1 mixture of liquid bacterial agent, with an inoculation volume of 10. 7 CFU / g soil.

[0083] Simultaneously apply 1.5% (w / w) of straw biochar with a particle size <2mm as a slow-release carbon source and a physically modified matrix.

[0084] Keep the soil moist and incubate at room temperature for 85 days. After incubation, if... Figure 8 As shown, the proportion of soil aggregates (≈0.25-5 mm) increased significantly from <5% before remediation to 16.5%. Soil organic matter content increased from almost 0% to 0.7%.

[0085] Vetiver and Miscanthus were selected as pioneer plants and transplanted by mixed cuttings with a row spacing of 30cm.

[0086] One year after restoration, the vegetation coverage reached 85%, forming a stable grass cover, such as Figure 5 As shown, the soil pH remained stable between 6.5 and 7.0. High-throughput sequencing revealed restored microbial community diversity, such as... Figure 2 As shown, the number of acidophilic oxidizing microorganisms decreased to 0.12 × 10⁻⁶. 6 CFU / g, such as Figure 10 As shown, Proteobacteria, Actinobacteria, Firmicutes, Acidobacteria, and Bacteroidetes are the dominant phyla.

[0087] Example 2

[0088] Remediation of acidic wastewater sedimentation ponds and surrounding contaminated soil in tin mines

[0089] Before remediation, the pH of the stagnant water in the mining area was 2.86, the pH of the soil was 3.0, and the total arsenic content was as high as 85 mg / kg, accompanied by high concentrations of iron and sulfate. The pollutants were mainly arsenic adsorbed on the surface of amorphous iron minerals, which was easily released again under acidic conditions. The microorganisms were mainly acidophilic iron-oxidizing archaea and sulfur-oxidizing bacteria.

[0090] Potassium persulfate was added to the water, sediment, and soil at a concentration of 8 mmol / L and mechanically mixed using a rotary tiller.

[0091] The reaction was maintained for 72 hours, utilizing the abundant ferrous ions and sulfides in the wastewater and sediment to catalyze persulfate, rapidly inactivating acidophilic microorganisms in the water and soil, and removing some of the Fe... 2+ Oxidized to Fe 3+ This forms an amorphous ferric arsenate / ferric hydroxysulfate coprecipitate precursor.

[0092] Adding 200-mesh limestone powder and ammonium alum to the water and sediment as a slow-release alkali source and ammonium ion source helps control NH4. + / Fe 3+ The molar ratio is approximately 0.6:1.

[0093] The pH of the system was raised to 6.1 within 40 days through slow stirring and natural sedimentation. During this process, the amorphous ferric hydroxyl sulfate precursor was reacted with NH4+. + Recrystallization occurs in its presence.

[0094] After standing for 42 days, XRD detected characteristic diffraction peaks of well-crystallized ferruginous minerals (potassium ferruginous alum, flavonoid ferruginous alum). Arsenic was detected as AsO4. 3- isomorphous substitution of SO4 2- It enters the flamonin iron alum lattice and achieves stable fixation.

[0095] Using TCLP testing, the arsenic leaching concentration decreased from 64 mg / L before remediation to below 25 mg / L. Figure 11 As shown.

[0096] The inoculation was performed using a bacterial agent primarily composed of locally selected, arsenic-resistant and extracellular electron-transfer-capable *Geobacterium thioreductoides*, at a dosage of 5 × 10⁻⁶. 6 CFU / g soil.

[0097] 1% sodium lactate and 0.5% humic acid were applied as a composite slow-release carbon source.

[0098] XRD patterns of pyrite mineral crystals in the sedimentation pond before reaction and XRD patterns of pyrite mineral crystal structures at different soil depths and oxygen environments in the sedimentation pond are shown below. Figure 12 As shown.

[0099] The EDX surface energy spectrum of the pyrite mineral crystals after the reaction is shown below. Figure 13 As shown.

[0100] After covering the stabilized sediment surface with 20 cm of soil, *Pteris vittata* was transplanted. *Pteris vittata* grew well, its roots forming a symbiotic system with functional microorganisms, further improving the local habitat. One year later, invasive, tolerant herbaceous plants appeared at the edge of the remediation area.

[0101] Example 3

[0102] Soil remediation of highly acidic waste rock dumps in metal mines

[0103] The waste rock, primarily composed of pyrite, is highly acidified, with leachate pH often below 2.0. The topsoil, actually weathered debris, has a pH of 2.5. Heavy metals are mainly copper, zinc, and cadmium. The local climate is arid with high evaporation rates, making moisture a limiting factor. The microbial community is dominated by extremely acidophilic iron-loving Leptospira, sulfur-oxidizing bacteria, and Thiobacillus.

[0104] Sodium persulfate was prepared into a high-concentration solution and sprayed onto the surface layer of the waste rock pile at a dose of 6 mmol / kg, from 0 to 30 cm.

[0105] After spraying, a water-retaining film is covered to reduce evaporation. The reaction lasts for 120 hours. The abundant pyrite in the waste rock catalyzes sodium disulfate, achieving efficient oxidation under low water conditions and inactivating acid-producing bacteria on the surface.

[0106] A composite mineral mixture of lightly calcined dolomite and potassium feldspar-montmorillonite is used as a composite conditioner. It is applied at 5% of the material mass, with potassium feldspar providing a slow-release potassium content. + Control K + / Fe 3+ The molar ratio is approximately 0.8:1 to accommodate the slow ion migration characteristic under arid conditions.

[0107] By applying small amounts of drip irrigation multiple times, the pH of the treatment layer material is slowly raised to 7.2 over 90 days. This long pH raising process is conducive to the slow growth of crystals.

[0108] Irrigation was stopped, and the ore was aged for 60 days under natural drought-wetting cycles. SEM-EDS analysis showed that a large amount of mixed crystalline layers of jaundice and goethite were formed on the surface and pores of the waste rock particles, encapsulating and fixing heavy metals. The EDX surface energy spectra of the ore in the early and late stages of the reaction are shown below. Figure 14 and Figure 15 As shown.

[0109] like Figure 16As shown, the contents of Cu, Zn, and Cd in the mining area were 135.7 mg / kg, 167.3 mg / kg, and 6.4 mg / kg, respectively. Leaching column experiments showed that the leaching amounts of heavy metals before soil remediation were 120.4 mg / kg, 143.65 mg / kg, and 5.2 mg / kg, respectively, while the leaching amounts after remediation were 13.56 mg / kg, 16.73 mg / kg, and 1.1 mg / kg, respectively. The heavy metals were effectively fixed after remediation, significantly reducing ecological risks.

[0110] Inoculate with a drought-resistant compound bacterial agent composed of native drought-resistant strains *Pseudomonas schlegelii* and *Bacillus subtilis*; *Pseudomonas schlegelii* possesses electroactive properties and EPS production capabilities. Mix the drought-resistant compound bacterial agent with the water-retaining agent polyacrylamide for application.

[0111] Apply a mixture of 2% cow and sheep manure compost and biochar, which serves as both a carbon source and a water-retaining covering layer.

[0112] Extremely drought-tolerant and barren-tolerant plants such as *Saussurea involucrata* and *Caragana korshinskii* were selected as pioneer shrubs. Container seedlings were transplanted with soil attached, and water collection and moisture retention measures were implemented.

[0113] Two years after restoration, the survival rate of the pioneer shrubs reached over 70%. Their crowns and root systems effectively reduced surface evaporation and soil erosion, and began to form a shady and humid microenvironment under the shrubs, promoting the accumulation of organic matter and the colonization of richer soil microorganisms, thus initiating the initial process of ecological succession in the extreme habitat of arid areas.

[0114] Advantages of this invention: The above technical solution achieves the following effects:

[0115] (1) Eradicating pollution sources and synergistic transformation: Creatively utilizing iron-sulfur minerals from pollution sources as catalysts to drive advanced oxidation processes, while efficiently inactivating acidophilic and free microorganisms colonizing iron-sulfur mineral bodies and cutting off the source of biological acidification, the acid-producing mineral precursors are simultaneously transformed into secondary mineral precursors (amorphous ferric hydroxysulfate) with the potential to fix heavy metals, realizing "waste treatment" and in-situ resource transformation of pollutants, and synergistically controlling the risk of acidification and heavy metal migration from the source;

[0116] (2) Long-term stability and self-sustaining microenvironment: The synergistic effect of slow-release alkali source and slow-release monovalent cationic minerals drives the formation of potassium ferric sulfate and other mineral phases into stable mineral phases under neutral to weakly acidic conditions. This process not only seals heavy metals for a long time through lattice fixation, but the stable mineral phase itself has good pH buffering capacity, which can maintain the neutral microenvironment of the remediated soil for a long time, effectively preventing the acidification rebound phenomenon common in the traditional lime method, and achieving long-term stability;

[0117] (3) Targeted ecological driving and rapid soil habitat construction: The introduced extracellular electroactive microorganisms act as ecological engineers. On the one hand, they competitively inhibit residual acidophilic bacteria through extracellular electron transfer. On the other hand, the abundant extracellular polymers (EPS) secreted by these microorganisms serve as natural and environmentally friendly soil cementing agents, which can rapidly and effectively promote the formation of water-stable soil aggregates. This fundamentally improves the physical structure problems of compaction and poor aeration and permeability that are common in acidified mining areas, creating an excellent growth space for plant roots, which cannot be achieved by simple chemical remediation.

[0118] (4) Formation of a complete ecological restoration closed loop: A complete technological closed loop of mutual promotion has been formed, which involves inactivating acidophilic microorganisms at the source (eliminating biological acid sources) → chemically transforming and passivating mineral acid sources and simultaneously fixing heavy metals (eliminating chemical toxicity) → introducing beneficial functional microorganisms (starting the ecological engine and improving soil physical structure) → supporting the establishment and growth of pioneer plants (achieving vegetation cover and ecological functions). This closed loop ultimately promotes the natural evolution of the damaged mining area ecosystem towards a healthy, stable, and self-sustaining direction, realizing a leap from simple pollution control to overall ecological restoration.

[0119] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included 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.

Claims

1. A micro-ecological regulation and restoration method based on the autocatalytic acidification control of mining areas, characterized in that, The micro-ecological regulation and restoration method based on the autocatalytic acidification control of the mining area includes the following steps: S1. Source Suppression of Acidity and Mineral Transformation: In acidified mining areas containing iron-sulfur minerals, persulfate is added to generate sulfate radicals and hydroxyl radicals, which inactivate acidophilic oxidizing microorganisms, oxidize and passivate the surface of iron-sulfur minerals, and generate amorphous secondary mineral phases including ferric hydroxysulfate, thereby inhibiting soil acidification and acidic mine water from the source. S2. Fixing heavy metals and stabilizing minerals: The pH of the mine soil system is gradually increased to 5.5-7.5 through slow-release alkali source. Under the action of monovalent cation slow-release minerals, the amorphous ferric sulfate secondary mineral phase generated in step S1 undergoes lattice reconstruction and is transformed into structurally stable jaundice or jaundice crystal minerals. The phase transition fixes the heavy metal ions in the solution into the mineral lattice through isomorphous substitution or adsorption, achieving long-term stability. S3. Microecological Reconstruction and Ecological Restoration: Introducing or enriching native extracellular electroactive microorganisms into the system treated in steps S1 and S2, and stimulating their metabolic activity by providing a slow-release carbon source or applying a micro-electric field; the extracellular electroactive microorganisms compete with the residual acidophilic microorganisms through extracellular electron transfer, producing antagonistic inhibition, while the metabolites secreted by the extracellular electroactive microorganisms promote the colonization and growth of acid-tolerant pioneer plants, thereby reconstructing a healthy microecology.

2. The micro-ecological regulation and restoration method based on the autocatalytic acidification control of mining areas according to claim 1, characterized in that, The iron-sulfur minerals present in situ in S1 are pyrite, pyrrhotite, or sulfur-containing tailings.

3. The micro-ecological regulation and restoration method based on the autocatalytic acidification control of mining areas according to claim 2, characterized in that, The persulfate added in S1 is permonosulfate or perdisulfate, and the amount of persulfate added is 1-8 millimoles of persulfate per kilogram of polluted soil or 1-8 millimoles of persulfate per cubic meter of acidic mine wastewater.

4. The micro-ecological regulation and restoration method based on the autocatalytic acidification control of mining areas according to claim 1, characterized in that, Before and after adding persulfate for the reaction, the treated area is tilled or stirred to a depth of 30-60 cm in S1 to ensure that the agent and minerals are in full contact, and the reaction time is not less than 72 hours.

5. The micro-ecological regulation and restoration method based on autocatalytic acidification control in mining areas according to claim 1, characterized in that, The monovalent cation of S2 is a slow-release potassium salt, sodium salt, and ammonium salt, which includes potassium feldspar, biotite, potash ore, and sodium sulfate.

6. The micro-ecological regulation and restoration method based on autocatalytic acidification control in mining areas according to claim 1, characterized in that, The slow-release alkali source of S2 is a mineral with a long-term slow-release effect, including dolomite, limestone and their modified minerals.

7. The micro-ecological regulation and restoration method based on autocatalytic acidification control in mining areas according to claim 1, characterized in that, The heavy metal ions in the solution of S2 are Cu. 2+ Pb 2+ Zn 2+ Cd 2+ .

8. The micro-ecological regulation and restoration method based on the autocatalytic acidification control of mining areas according to claim 1, characterized in that, The extracellular electroactive microorganisms in S3 include one or more of the following selected and domesticated from the local mining area: *Geobacterium thioreductoides*, *Schizella oneneidae*, and *Pseudomonas aeruginosa*.

9. The micro-ecological regulation and restoration method based on the autocatalytic acidification control of mining areas according to claim 1, characterized in that, The slow-release carbon source in S3 is sodium lactate, sodium acetate, or straw biochar, and the amount of the slow-release carbon source added is 0.5%-2% of the soil mass.

10. The micro-ecological regulation and restoration method based on autocatalytic acidification control in mining areas according to claim 1, characterized in that, The acid-resistant pioneer plants in S3 are one or more combinations of Miscanthus sinensis, Vetiver, Reed, and Centipede Grass.

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