Tailing composite modifier for acid soil treatment and preparation method thereof

Abstract

The invention relates to the technical field of tailing treatment, and particularly discloses a tailing composite modifier for acid soil treatment and a preparation method thereof.The tailing composite modifier is prepared from, by weight, 30-60 parts of alkaline conditioning materials, 20-50 parts of organic matter materials, 10-30 parts of mineral adsorption materials, 0.5-5 parts of microbial agents and 10 parts of tailing powder. The alkaline conditioning material is selected from one or more of quick lime, slaked lime, calcium carbonate, dolomite powder, steel slag, carbide slag and red mud, and the organic matter material is selected from one or more of humic acid, weathered coal, decomposed straw, decomposed livestock and poultry manure, biochar and organic sludge fermentation products. The mineral adsorption material is selected from one or more of bentonite, sepiolite, zeolite, vermiculite, attapulgite and ardealite. According to the tailing composite modifier for acidic soil treatment and the preparation method of the tailing composite modifier, efficient, stable and long-acting ecological restoration can be carried out on acidic soil.

Description

Technical Field

[0001] This invention relates to the field of tailings management technology, specifically to a composite tailings amendment for acidic soil management and its preparation method. Background Technology

[0002] The remediation of acidic soils faces multiple obstacles, including low pH, high heavy metal activity, nutrient deficiency, and loss of microbial function. Current technologies primarily employ methods such as applying alkaline substances like lime, adding passivating materials, or increasing organic fertilizer application. However, these methods generally suffer from limited effectiveness, lack of long-term sustainability, or the potential to cause soil compaction. While composite soil conditioners have emerged in recent years and achieved initial synergy through the physical mixing of multiple materials, they still suffer from insufficient internal functional coupling, easy loss of added nutrients, difficulty in establishing and utilizing exogenous microorganisms in harsh environments, and a lack of long-term self-sustaining mechanisms. These shortcomings prevent them from fundamentally driving the benign cycle and stable recovery of damaged ecosystems.

[0003] Chinese patent CN119463883A discloses a soil conditioner prepared from industrial tailings, its preparation method, and its application in improving acidic arable land. The soil conditioner of this invention comprises a powder obtained by calcining and pulverizing basic raw materials and additives; the basic raw materials include 85-95 parts by weight of phosphate tailings and 2-10 parts by weight of plant straw; the additives are 3-5 parts by weight. This invention can utilize phosphate tailings and crop straw as main raw materials to manufacture an acidic soil conditioner. The preparation process is simple, low-cost, and has good treatment effects, enabling the treatment of acidic arable land. It can also be used as a soil conditioner for calcium magnesium phosphate fertilizer application, along with its preparation method and application. However, this method cannot achieve slow release and biological cycling of nutrients, and cannot achieve efficient, stable, and long-term ecological restoration of acidic soil. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides: a tailings composite amendment for acidic soil remediation and its preparation method, which is made from the following raw materials in parts by weight:

[0005] 30-60 parts alkaline conditioning material, 20-50 parts organic material, 10-30 parts mineral adsorbent material, 0.5-5 parts microbial agent, and 10 parts tailings powder.

[0006] Preferably, the alkaline conditioning material is selected from one or more of quicklime, hydrated lime, calcium carbonate, dolomite powder, steel slag, carbide slag, and red mud.

[0007] Preferably, the organic material is selected from one or more of humic acid, weathered coal, decomposed straw, decomposed livestock and poultry manure, biochar, and organic sludge fermentation products.

[0008] Preferably, the mineral adsorbent material is selected from one or more of bentonite, sepiolite, zeolite, vermiculite, attapulgite, and phosphogypsum.

[0009] Preferably, the microbial agent contains at least one of nitrogen-fixing bacteria, phosphate-solubilizing bacteria, potassium-solubilizing bacteria, and photosynthetic bacteria, and the total number of viable bacteria is not less than 2.0 × 10^8 CFU / g.

[0010] Preferably, the raw materials further include 5-15 parts of a bio-mineral composite conditioning core, and the preparation method of the bio-mineral composite conditioning core is as follows:

[0011] S1. Mineral carrier modification:

[0012] The zeolite ore was crushed to 100 mesh and placed in a 1.5 mol / L citric acid solution. The mixture was stirred at 60°C for 3 hours. After the reaction was completed, the mixture was filtered and washed with deionized water until the filtrate was neutral. The filter cake was dried at 105°C and then placed in a muffle furnace and calcined at 350°C for 2 hours to obtain an acidified-thermally activated modified mineral carrier, which was then cooled for later use.

[0013] S2. Preparation of functionalized biochar:

[0014] Rice husks were washed, dried, and crushed, then placed in a tube furnace and heated to 550°C at a rate of 10°C / min under nitrogen protection. The temperature was maintained for pyrolysis for 1 hour, and after natural cooling, basic biochar was obtained. The biochar was then ground through a 100-mesh sieve and immersed in a 10% diammonium hydrogen phosphate solution. The mixture was shaken and impregnated for 24 hours, then filtered. The nutrient-loaded wet biochar was vacuum dried at 80°C to constant weight to obtain nitrogen and phosphorus functionalized biochar.

[0015] S3. Compound microbial agent propagation and protection:

[0016] The selected acid-tolerant nitrogen-fixing bacteria and phosphate-solubilizing fungi were cultured in liquid culture to the late logarithmic growth phase. The three bacterial solutions were mixed in equal volume ratio to obtain a composite microbial solution. A protectant was added to the bacterial solution and mixed evenly to prepare a microbial protective suspension.

[0017] S4. Assembly and granulation of conditioning cores:

[0018] The following dry-mixed materials were prepared in weight percentages: 70 parts of the modified mineral carrier obtained in step S1, 25 parts of the nitrogen and phosphorus functionalized biochar obtained in step S2, and 5 parts of the binder. The above dry-mixed materials were thoroughly mixed in a mixer for 10 minutes. Then, under stirring, the microbial protective suspension prepared in step S3 was slowly sprayed. The spraying amount was controlled so that the final water content of the mixture reached 20 parts. The moistened material was fed into a disc granulator to produce uniform particles with a particle size of 2 mm.

[0019] S5, Low-temperature curing and post-curing:

[0020] The wet granules were dried at low temperature under circulating ventilation at 40℃ for 18 hours to reduce their moisture content to below 15%. The dried granules were then placed in a cool, room-temperature environment for 10 days to allow microorganisms to adapt and stabilize inside the granules, thus obtaining the final biological-mineral composite conditioning core.

[0021] Preferably, the bio-mineral composite conditioning core is composed of an acidified-thermally activated porous mineral carrier, nitrogen and phosphorus functionalized biochar, and a targeted composite microbial agent, which are then compounded through a granulation process.

[0022] A method for preparing a tailings composite amendment for acidic soil remediation includes the following steps:

[0023] S1. Raw material pretreatment: The alkaline conditioning material, organic material and mineral adsorbent material are crushed to a fineness of 80 mesh or higher.

[0024] S2, Primary Mixing: The pretreated alkaline conditioning material, organic material and mineral adsorbent material are added into the mixer in proportion and the first stage of dry mixing is carried out for 10-30 minutes to obtain the basic mixture;

[0025] S3. Conditioning Core Addition: After diluting the biological-mineral composite conditioning core, it is uniformly added to the base mixture by atomization spraying, while simultaneously performing a second-stage wet mixing.

[0026] S4. Aging and Drying: The uniformly mixed material is aged at room temperature for 24-72 hours, and then dried at a low temperature of 50-70℃ until the moisture content is below 15%.

[0027] S5. Finished product processing: The dried material is screened, measured and packaged.

[0028] This invention provides a composite amendment for tailings remediation in acidic soil and its preparation method. It has the following beneficial effects:

[0029] This invention achieves synergistic "chemical-physical-biological" governance. It not only neutralizes acidity and improves soil structure through the scientific combination of multiple materials, but more importantly, it introduces a "biological-mineral composite conditioning core" as the core of ecological driving. Its unique structure provides microorganisms with colonization shelter in adversity, realizes the slow release and biological cycle of nutrients, and enhances the passivation ability of heavy metals, thereby constructing a rhizosphere micro-ecosystem with self-sustaining function. At the same time, the preparation process takes into account the maintenance of microbial activity and industrial feasibility, and realizes the resource utilization of bulk solid waste, ultimately achieving efficient, stable and long-term ecological restoration of acidic soil. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention have been clearly and completely described. 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.

[0031] In a first embodiment, the present invention provides a technical solution: a tailings composite amendment for acidic soil remediation, made from the following raw materials in parts by weight:

[0032] 30 parts quicklime, 20 parts biochar, 10 parts zeolite, 0.5 parts phosphate-solubilizing bacteria, and 10 parts tailings powder;

[0033] The preparation method is as follows:

[0034] S1. Raw material pretreatment: The quicklime, biochar and zeolite are crushed to a fineness of 80 mesh or higher.

[0035] S2. Primary mixing: The pretreated quicklime, biochar and zeolite are added to the mixer in proportion and the first stage of dry mixing is carried out for 10 minutes to obtain the basic mixture.

[0036] S3. Aging and Drying: The uniformly mixed material is aged at room temperature for 24 hours, and then dried at a low temperature of 50℃ until the moisture content is below 15%;

[0037] S4. Finished product processing: The dried material is screened, measured and packaged.

[0038] In a second embodiment, the present invention provides a technical solution: a tailings composite amendment for acidic soil remediation, made from the following raw materials in parts by weight:

[0039] 40 parts quicklime, 35 parts biochar, 20 parts zeolite, 2.5 parts phosphate-solubilizing bacteria, and 10 parts tailings powder.

[0040] The preparation method is as follows:

[0041] S1. Raw material pretreatment: The quicklime, biochar and zeolite are crushed to a fineness of 80 mesh or higher.

[0042] S2. Primary mixing: The pretreated quicklime, biochar and zeolite are added to the mixer in proportion and the first stage of dry mixing is carried out for 20 minutes to obtain the basic mixture.

[0043] S3. Aging and Drying: The uniformly mixed material is aged at room temperature for 48 hours, and then dried at a low temperature of 60℃ until the moisture content is less than 15%;

[0044] S4. Finished product processing: The dried material is screened, measured and packaged.

[0045] In a third embodiment, the present invention provides a technical solution: a composite amendment for tailings in acidic soil remediation, made from the following raw materials in parts by weight:

[0046] 60 parts quicklime, 50 parts biochar, 30 parts zeolite, 5 parts phosphate-solubilizing bacteria, and 10 parts tailings powder.

[0047] The preparation method is as follows:

[0048] S1. Raw material pretreatment: The quicklime, biochar and zeolite are crushed to a fineness of 80 mesh or higher.

[0049] S2. Primary mixing: The pretreated quicklime, biochar and zeolite are added to the mixer in proportion and the first stage of dry mixing is carried out for 30 minutes to obtain the basic mixture.

[0050] S3. Aging and Drying: The uniformly mixed material is aged at room temperature for 72 hours, and then dried at a low temperature of 70℃ until the moisture content is less than 15%;

[0051] S4. Finished product processing: The dried material is screened, measured and packaged.

[0052] Fourth embodiment: The present invention provides a technical solution: a tailings composite amendment for acidic soil remediation, made from the following raw materials in parts by weight:

[0053] 40 parts quicklime, 35 parts biochar, 20 parts zeolite, 2.5 parts phosphate-solubilizing bacteria, 10 parts biological-mineral composite conditioning core, and 10 parts tailings powder.

[0054] The preparation method is as follows:

[0055] S1. Preparation of bio-mineral composite conditioning core:

[0056] S1.1, Mineral carrier modification:

[0057] The zeolite ore was crushed to 100 mesh and placed in a 1.5 mol / L citric acid solution. The mixture was stirred at 60°C for 3 hours. After the reaction was completed, the mixture was filtered and washed with deionized water until the filtrate was neutral. The filter cake was dried at 105°C and then placed in a muffle furnace and calcined at 350°C for 2 hours to obtain an acidified-thermally activated modified mineral carrier, which was then cooled for later use.

[0058] S1.2 Preparation of Functionalized Biochar:

[0059] Rice husks were washed, dried, and crushed, then placed in a tube furnace and heated to 550°C at a rate of 10°C / min under nitrogen protection. The temperature was maintained for pyrolysis for 1 hour, and after natural cooling, basic biochar was obtained. The biochar was then ground through a 100-mesh sieve and immersed in a 10% diammonium hydrogen phosphate solution. The mixture was shaken and impregnated for 24 hours, then filtered. The nutrient-loaded wet biochar was vacuum dried at 80°C to constant weight to obtain nitrogen and phosphorus functionalized biochar.

[0060] S1.3, Compound Microbial Agent Propagation and Protection:

[0061] The selected acid-tolerant nitrogen-fixing bacteria and phosphate-solubilizing fungi were cultured in liquid culture to the late logarithmic growth phase. The three bacterial solutions were mixed in equal volume ratio to obtain a composite microbial solution. A protectant was added to the bacterial solution and mixed evenly to prepare a microbial protective suspension.

[0062] S1.4 Assembly and granulation of conditioning cores:

[0063] The following dry-mixed materials were prepared in weight percentages: 70 parts of the modified mineral carrier obtained in step S1, 25 parts of the nitrogen and phosphorus functionalized biochar obtained in step S2, and 5 parts of the binder. The above dry-mixed materials were thoroughly mixed in a mixer for 10 minutes. Then, under stirring, the microbial protective suspension prepared in step S3 was slowly sprayed. The spraying amount was controlled so that the final water content of the mixture reached 20 parts. The moistened material was fed into a disc granulator to produce uniform particles with a particle size of 2 mm.

[0064] S1.5, Low-temperature curing and post-curing:

[0065] The wet granules were dried at low temperature under circulating ventilation at 40℃ for 18 hours to reduce their moisture content to below 15%. The dried granules were then placed in a cool, room-temperature environment for 10 days to allow microorganisms to adapt to and stabilize inside the granules, thus obtaining the final biological-mineral composite conditioning core.

[0066] S2. Raw material pretreatment: The quicklime, biochar and zeolite are crushed to a fineness of 80 mesh or higher.

[0067] S3. Primary mixing: The pretreated quicklime, biochar and zeolite are added to the mixer in proportion and the first stage of dry mixing is carried out for 20 minutes to obtain the basic mixture.

[0068] S4. Conditioning Core Addition: After diluting the bio-mineral composite conditioning core prepared in step S1, it is uniformly added to the base mixture by atomized spraying, while simultaneously performing a second-stage wet mixing.

[0069] S5. Aging and Drying: The uniformly mixed material is aged at room temperature for 48 hours, and then dried at a low temperature of 60℃ until the moisture content is less than 15%;

[0070] S6. Finished product processing: The dried material is screened, measured and packaged.

[0071] Fifth embodiment: The present invention provides a technical solution: a tailings composite amendment for acidic soil remediation, made from the following raw materials in parts by weight:

[0072] 30 parts quicklime, 20 parts biochar, 10 parts zeolite, 0.5 parts phosphate-solubilizing bacteria, 5 parts biological-mineral composite conditioning core, and 10 parts tailings powder;

[0073] The preparation method is as follows:

[0074] S1. Preparation of bio-mineral composite conditioning core:

[0075] S1.1, Mineral carrier modification:

[0076] The zeolite ore was crushed to 100 mesh and placed in a 1.5 mol / L citric acid solution. The mixture was stirred at 60°C for 3 hours. After the reaction was completed, the mixture was filtered and washed with deionized water until the filtrate was neutral. The filter cake was dried at 105°C and then placed in a muffle furnace and calcined at 350°C for 2 hours to obtain an acidified-thermally activated modified mineral carrier, which was then cooled for later use.

[0077] S1.2 Preparation of Functionalized Biochar:

[0078] Rice husks were washed, dried, and crushed, then placed in a tube furnace and heated to 550°C at a rate of 10°C / min under nitrogen protection. The temperature was maintained for pyrolysis for 1 hour, and after natural cooling, basic biochar was obtained. The biochar was then ground through a 100-mesh sieve and immersed in a 10% diammonium hydrogen phosphate solution. The mixture was shaken and impregnated for 24 hours, then filtered. The nutrient-loaded wet biochar was vacuum dried at 80°C to constant weight to obtain nitrogen and phosphorus functionalized biochar.

[0079] S1.3, Compound Microbial Agent Propagation and Protection:

[0080] The selected acid-tolerant nitrogen-fixing bacteria and phosphate-solubilizing fungi were cultured in liquid culture to the late logarithmic growth phase. The three bacterial solutions were mixed in equal volume ratio to obtain a composite microbial solution. A protectant was added to the bacterial solution and mixed evenly to prepare a microbial protective suspension.

[0081] S1.4 Assembly and granulation of conditioning cores:

[0082] The following dry-mixed materials were prepared in weight percentages: 70 parts of the modified mineral carrier obtained in step S1, 25 parts of the nitrogen and phosphorus functionalized biochar obtained in step S2, and 5 parts of the binder. The above dry-mixed materials were thoroughly mixed in a mixer for 10 minutes. Then, under stirring, the microbial protective suspension prepared in step S3 was slowly sprayed. The spraying amount was controlled so that the final water content of the mixture reached 20 parts. The moistened material was fed into a disc granulator to produce uniform particles with a particle size of 2 mm.

[0083] S1.5, Low-temperature curing and post-curing:

[0084] The wet granules were dried at low temperature under circulating ventilation at 40℃ for 18 hours to reduce their moisture content to below 15%. The dried granules were then placed in a cool, room-temperature environment for 10 days to allow microorganisms to adapt to and stabilize inside the granules, thus obtaining the final biological-mineral composite conditioning core.

[0085] S2. Raw material pretreatment: The quicklime, biochar and zeolite are crushed to a fineness of 80 mesh or higher.

[0086] S3. Primary mixing: The pretreated quicklime, biochar and zeolite are added to the mixer in proportion and the first stage of dry mixing is carried out for 10 minutes to obtain the basic mixture.

[0087] S4. Conditioning Core Addition: After diluting the bio-mineral composite conditioning core prepared in step S1, it is uniformly added to the base mixture by atomized spraying, while simultaneously performing a second-stage wet mixing.

[0088] S5. Aging and Drying: The uniformly mixed material is aged at room temperature for 24 hours, and then dried at a low temperature of 50℃ until the moisture content is below 15%;

[0089] S6. Finished product processing: The dried material is screened, measured and packaged.

[0090] In the sixth embodiment, the present invention provides a technical solution: a tailings composite amendment for acidic soil remediation, made from the following raw materials in parts by weight:

[0091] 60 parts quicklime, 50 parts biochar, 30 parts zeolite, 5 parts phosphate-solubilizing bacteria, 15 parts biological-mineral composite conditioning core, and 10 parts tailings powder.

[0092] The preparation method is as follows:

[0093] S1. Preparation of bio-mineral composite conditioning core:

[0094] S1.1, Mineral carrier modification:

[0095] The zeolite ore was crushed to 100 mesh and placed in a 1.5 mol / L citric acid solution. The mixture was stirred at 60°C for 3 hours. After the reaction was completed, the mixture was filtered and washed with deionized water until the filtrate was neutral. The filter cake was dried at 105°C and then placed in a muffle furnace and calcined at 350°C for 2 hours to obtain an acidified-thermally activated modified mineral carrier, which was then cooled for later use.

[0096] S1.2 Preparation of Functionalized Biochar:

[0097] Rice husks were washed, dried, and crushed, then placed in a tube furnace and heated to 550°C at a rate of 10°C / min under nitrogen protection. The temperature was maintained for pyrolysis for 1 hour, and after natural cooling, basic biochar was obtained. The biochar was then ground through a 100-mesh sieve and immersed in a 10% diammonium hydrogen phosphate solution. The mixture was shaken and impregnated for 24 hours, then filtered. The nutrient-loaded wet biochar was vacuum dried at 80°C to constant weight to obtain nitrogen and phosphorus functionalized biochar.

[0098] S1.3, Compound Microbial Agent Propagation and Protection:

[0099] The selected acid-tolerant nitrogen-fixing bacteria and phosphate-solubilizing fungi were cultured in liquid culture to the late logarithmic growth phase. The three bacterial solutions were mixed in equal volume ratio to obtain a composite microbial solution. A protectant was added to the bacterial solution and mixed evenly to prepare a microbial protective suspension.

[0100] S1.4 Assembly and granulation of conditioning cores:

[0101] The following dry-mixed materials were prepared in weight percentages: 70 parts of the modified mineral carrier obtained in step S1, 25 parts of the nitrogen and phosphorus functionalized biochar obtained in step S2, and 5 parts of the binder. The above dry-mixed materials were thoroughly mixed in a mixer for 10 minutes. Then, under stirring, the microbial protective suspension prepared in step S3 was slowly sprayed. The spraying amount was controlled so that the final water content of the mixture reached 20 parts. The moistened material was fed into a disc granulator to produce uniform particles with a particle size of 2 mm.

[0102] S1.5, Low-temperature curing and post-curing:

[0103] The wet granules were dried at low temperature under circulating ventilation at 40℃ for 18 hours to reduce their moisture content to below 15%. The dried granules were then placed in a cool, room-temperature environment for 10 days to allow microorganisms to adapt to and stabilize inside the granules, thus obtaining the final biological-mineral composite conditioning core.

[0104] S2. Raw material pretreatment: The quicklime, biochar and zeolite are crushed to a fineness of 80 mesh or higher.

[0105] S3. Primary mixing: The pretreated quicklime, biochar and zeolite are added to the mixer in proportion and the first stage of dry mixing is carried out for 30 minutes to obtain the basic mixture.

[0106] S4. Conditioning Core Addition: After diluting the bio-mineral composite conditioning core prepared in step S1, it is uniformly added to the base mixture by atomized spraying, while simultaneously performing a second-stage wet mixing.

[0107] S5. Aging and Drying: The uniformly mixed material is aged at room temperature for 72 hours, and then dried at a low temperature of 70℃ until the moisture content is below 15%;

[0108] S6. Finished product processing: The dried material is screened, measured and packaged.

[0109] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A composite amendment for tailings in acidic soil remediation, characterized in that, It is made from the following raw materials in parts by weight: 30-60 parts alkaline conditioning material, 20-50 parts organic material, 10-30 parts mineral adsorbent material, 0.5-5 parts microbial agent, and 10 parts tailings powder.

2. The tailings composite amendment for acidic soil remediation according to claim 1, characterized in that: The alkaline conditioning material is selected from one or more of quicklime, hydrated lime, calcium carbonate, dolomite powder, steel slag, carbide slag, and red mud.

3. The tailings composite amendment for acidic soil remediation according to claim 1, characterized in that: The organic material is selected from one or more of the following: humic acid, weathered coal, decomposed straw, decomposed livestock and poultry manure, biochar, and fermented organic sludge.

4. The tailings composite amendment for acidic soil remediation according to claim 1, characterized in that: The mineral adsorbent material is selected from one or more of bentonite, sepiolite, zeolite, vermiculite, attapulgite, and phosphogypsum.

5. The tailings composite amendment for acidic soil remediation according to claim 1, characterized in that: The microbial agent contains at least one of nitrogen-fixing bacteria, phosphate-solubilizing bacteria, potassium-solubilizing bacteria, and photosynthetic bacteria, and the total number of viable bacteria is not less than 2.0 × 10^8 CFU / g.

6. The tailings composite amendment for acidic soil remediation according to claim 1, characterized in that: The raw materials also include 5-15 parts of a bio-mineral composite conditioning core, and the preparation method of the bio-mineral composite conditioning core is as follows: S1. Mineral carrier modification: The zeolite ore was crushed to 100 mesh and placed in a 1.5 mol / L citric acid solution. The mixture was stirred at 60°C for 3 hours. After the reaction was completed, the mixture was filtered and washed with deionized water until the filtrate was neutral. The filter cake was dried at 105°C and then placed in a muffle furnace and calcined at 350°C for 2 hours to obtain an acidified-thermally activated modified mineral carrier, which was then cooled for later use. S2. Preparation of functionalized biochar: Rice husks were washed, dried, and crushed, then placed in a tube furnace and heated to 550°C at a rate of 10°C / min under nitrogen protection. The temperature was maintained for pyrolysis for 1 hour, and after natural cooling, basic biochar was obtained. The biochar was then ground through a 100-mesh sieve and immersed in a 10% diammonium hydrogen phosphate solution. The mixture was shaken and impregnated for 24 hours, then filtered. The nutrient-loaded wet biochar was vacuum dried at 80°C to constant weight to obtain nitrogen and phosphorus functionalized biochar. S3. Compound microbial agent propagation and protection: The selected acid-tolerant nitrogen-fixing bacteria and phosphate-solubilizing fungi were cultured in liquid culture to the late logarithmic growth phase. The three bacterial solutions were mixed in equal volume ratio to obtain a composite microbial solution. A protectant was added to the bacterial solution and mixed evenly to prepare a microbial protective suspension. S4. Assembly and granulation of conditioning cores: The following dry-mixed materials were prepared in weight percentages: 70 parts of the modified mineral carrier obtained in step S1, 25 parts of the nitrogen and phosphorus functionalized biochar obtained in step S2, and 5 parts of the binder. The above dry-mixed materials were thoroughly mixed in a mixer for 10 minutes. Then, under stirring, the microbial protective suspension prepared in step S3 was slowly sprayed. The spraying amount was controlled so that the final water content of the mixture reached 20 parts. The moistened material was fed into a disc granulator to produce uniform particles with a particle size of 2 mm. S5, Low-temperature curing and post-curing: The wet granules were dried at low temperature under circulating ventilation at 40℃ for 18 hours to reduce their moisture content to below 15%. The dried granules were then placed in a cool, room-temperature environment for 10 days to allow microorganisms to adapt and stabilize inside the granules, thus obtaining the final biological-mineral composite conditioning core.

7. The tailings composite amendment for acidic soil remediation according to claim 1, characterized in that: The bio-mineral composite conditioning core is composed of an acidified-thermally activated modified porous mineral carrier, nitrogen and phosphorus functionalized biochar, and targeted composite microbial agents through a granulation process.

8. A method for preparing a composite amendment for tailings in acidic soil remediation, characterized in that, Includes the following steps: S1. Raw material pretreatment: The alkaline conditioning material, organic material and mineral adsorbent material are crushed to a fineness of 80 mesh or higher. S2, Primary Mixing: The pretreated alkaline conditioning material, organic material and mineral adsorbent material are added into the mixer in proportion and the first stage of dry mixing is carried out for 10-30 minutes to obtain the basic mixture; S3. Conditioning Core Addition: After diluting the biological-mineral composite conditioning core, it is uniformly added to the base mixture by atomization spraying, while simultaneously performing a second-stage wet mixing. S4. Aging and Drying: The uniformly mixed material is aged at room temperature for 24-72 hours, and then dried at a low temperature of 50-70℃ until the moisture content is below 15%. S5. Finished product processing: The dried material is screened, measured and packaged.