Wide-proportion ecological nutrient soil based on geopolymer modified iron tailings and preparation method of wide-proportion ecological nutrient soil

Abstract

The invention discloses wide-proportion ecological nutrient soil based on geopolymer modified iron tailings and a preparation method of the wide-proportion ecological nutrient soil, relates to the technical field of waste resource utilization and ecological restoration, and aims to solve the technical problems of land occupation due to accumulation of the iron tailings, heavy metal pollution, structure hardening and low resource utilization rate. Iron tailings are used as a core raw material and matched with a geopolymer gel system to construct a stable framework and solidify heavy metal, organic nutrient components and a function regulator are compounded to optimize physicochemical properties and nutrient supply, and the ecological nutrient soil is prepared through the processes of raw material pretreatment, synergistic excitation, gradient maintenance and the like. According to the nutrient soil, large-scale flexible absorption (the proportion is 40-80%) of the iron tailings is achieved, meanwhile, the nutrient soil has a pore structure suitable for plant growth, the water and fertilizer retention capacity and the pH value (6.0-7.8) are achieved, the heavy metal leaching amount meets the Soil Environment Quality Agricultural Land Soil Pollution Risk Management and Control Standard, and the method is suitable for large-scale popularization and application. The multi-scene plant growth requirements of farmland improvement, landscaping, mine regreening, side slope ecological protection and the like can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste resource utilization and ecological restoration, more specifically, to a wide-proportion ecological nutrient soil based on geopolymer modified iron tailings and a preparation method thereof. BACKGROUND

[0002] Iron tailings are the main solid waste generated in the process of iron ore mining and beneficiation. This kind of solid waste not only occupies a large amount of land resources, but also contains heavy metals such as lead, cadmium, arsenic and chromium, which can continuously pollute the surrounding soil, water and air through leaching and weathering processes, leading to soil quality degradation and difficulty in vegetation survival. At the same time, iron tailings are dense, with a low porosity and poor water and fertilizer retention capacity, making natural restoration extremely difficult, which has become a key ecological bottleneck restricting the green and sustainable development of the steel industry.

[0003] At present, the resource utilization of iron tailings mainly focuses on low-value road base fillers, brick-making raw materials, cement admixtures, etc., with a utilization rate of less than 30%, and the problem of heavy metal pollution and structural hardening has not been fundamentally solved. In the existing technology of preparing nutrient soil from solid waste, the addition amount of iron tailings is generally less than 50%, which cannot realize large-scale consumption, and there are problems such as fixed proportion, poor adaptability, limited heavy metal stabilization effect, insufficient structural stability of nutrient soil, etc., which cannot meet the ecological restoration and plant growth requirements of different scenes.

[0004] As a new type of inorganic cementing material, geopolymer is formed by alkali activation reaction of aluminosilicate raw materials to form a three-dimensional network structure, which not only has the characteristics of high strength and high stability, but also can effectively immobilize heavy metals through physical encapsulation, chemical adsorption and chemical bonding. It can also produce good interfacial bonding and synergistic reaction with the silicate and aluminate components in iron tailings, optimizing the soil pore structure. At the same time, the geopolymer cementing system can be flexibly adjusted according to the addition amount of iron tailings, adapting to the performance requirements of a wide proportion range. SUMMARY

[0005] In view of the problems of serious pollution, low utilization rate and structural hardening of iron tailings, and the problems of limited consumption, fixed proportion and poor adaptability of existing solid waste nutrient soil, one of the purposes of the present application is to provide a wide-proportion ecological nutrient soil based on geopolymer modified iron tailings, which realizes large-scale flexible consumption (40-80%) and harmless disposal of iron tailings, and at the same time obtains high-quality ecological nutrient soil suitable for plant growth in multiple scenes.

[0006] To solve the above technical problems, the present application provides the following technical solutions: A wide-proportion ecological nutrient soil based on geopolymer modified iron tailings, comprising the following raw materials by weight: iron tailings (iron ore mining / mining byproducts) 40-80 parts, geopolymer cementing system 10-25 parts, organic nutrient component 5-15 parts, functional regulator 2-6 parts, and water 5-9 parts.

[0007] Preferably, the particle size of the iron tailings is 100-200 mesh, wherein the SiO2 content is ≥50%, the Al2O3 content is ≥8%, the Fe2O3 content is 15-30%, the water content is ≤5%, and the pH value is 6.5-9.0; after pretreatment, the heavy metal (lead, cadmium, arsenic, chromium, etc.) leaching amount meets the GB 15618-2018 standard.

[0008] Preferably, the geopolymer cementing system is compounded by an alkali activator and an aluminosilicate precursor at a mass ratio of 1:2.5-1:5; the alkali activator is a mixed system of sodium hydroxide and water glass, and the mass ratio of sodium hydroxide to water glass is 1:3-1:6, and the modulus of the water glass is 2.0-2.8; the aluminosilicate precursor is a mixture of one or more of fly ash, slag, and metakaolin, and the active SiO2+Al2O3 content in the aluminosilicate precursor is ≥75%.

[0009] Preferably, the organic nutrient component is a mixture of one or more of decomposed straw, humus soil, biochar, and decomposed livestock and poultry manure, and the organic matter content is ≥45% and the particle size is ≤3 mm.

[0010] Preferably, the functional regulator is compounded by a water-retaining agent, slow-release fertilizer, heavy metal stabilizer, and pH regulator at a mass ratio of 1:1:1:1-2:1:1:1; the water-retaining agent is a polyacrylamide water-retaining agent; the slow-release fertilizer is a urea-formaldehyde resin coated compound fertilizer; the heavy metal stabilizer is humic acid, zeolite powder, or phosphorite powder; and the pH regulator is wood ash or potassium dihydrogen phosphate.

[0011] The core innovation of the present application is to break through the dual bottleneck of consumption amount and proportion adaptability of traditional iron tailings utilization, take 40-80 parts by weight of iron tailings as the core raw material, and utilize the triple action of the geopolymer cementing system: first, build a nutrient soil stable skeleton through a three-dimensional network structure, break the iron tailings' caking characteristics, and optimize the pore structure to provide sufficient space for plant root growth; second, solidify heavy metals through physical wrapping, chemical adsorption, and chemical bonding to block their migration and diffusion path and reduce pollution risk; third, the cementing system proportion can be flexibly adjusted with the addition amount of iron tailings to ensure stable performance of the nutrient soil under different proportions; and finally, combine the nutrient supply function of the organic nutrient component and the performance optimization effect of the functional regulator to prepare an ecological nutrient soil that has the characteristics of flexible consumption, heavy metal stabilization, and multi-scene adaptation through scientific proportioning and process control.

[0012] As the core raw material, the iron tailings are rich in SiO2 and Al2O3, which can have a synergistic alkali-activation reaction with the geopolymer cementitious system, ensuring the structural stability of the nutrient soil and realizing a wide range of absorption (40-80 parts); the geopolymer cementitious system selects industrial solid wastes such as fly ash and slag as aluminosilicate precursors, further improving the comprehensive utilization efficiency of solid wastes and realizing "waste treatment with waste". The organic nutrient component provides organic matter, nitrogen, phosphorus, potassium and other nutrients required for plant growth, and improves soil aggregation; the functional regulator optimizes the water retention, slow-release fertilizer efficiency and pH value, and at the same time strengthens the heavy metal stabilization effect, ensuring the ecological safety and scene adaptability of the nutrient soil.

[0013] The second purpose of the present application is to provide a preparation method of a wide-proportion ecological nutrient soil based on geopolymer modified iron tailings, comprising the following steps: (1) The raw materials are treated by a combined process of "magnetic separation and chemical stabilization": the iron tailings are dried to a water content of ≤5%, crushed and then sieved through a 100-200 mesh sieve, the ferromagnetic impurities and part of the heavy metal sulfides are removed by magnetic separation, then 1-3% of a heavy metal stabilizer by mass of the iron tailings is added, the mixture is stirred uniformly and then left to stand for 24-48 hours to reduce the activity of heavy metals through adsorption and chelation; the organic nutrient component is crushed to a particle size of ≤3 mm and reserved; (2) Preparation of the geopolymer cementitious system: the alkali activator and the aluminosilicate precursor are mixed in proportion, stirred uniformly and then left to stand for 15-30 minutes to ensure that the alkali activation activity is fully released, and reserved; (3) Mixing and stirring: the pretreated iron tailings and the organic nutrient component are first added to a stirrer, dry-mixed for 8-15 minutes until they are uniformly mixed; then the geopolymer cementitious system and water are added, wet-mixed for 20-30 minutes until the material is loose and free of lumps, and the stirring speed is controlled at 350-500 r / min; (4) Activation and curing: the mixed material is spread on a curing site, the environmental temperature is controlled at 22-32℃, the humidity is controlled at 65-85%, and the material is cured for 5-10 days; it is cured in a closed environment for the first 3 days, and then it is turned over once a day and gradually ventilated and dehumidified for the next 7 days to ensure uniform curing and stable structure; (5) Product processing: after curing, the material is crushed and sieved through an 8-10 mesh sieve, and a small amount of lumps and impurities are removed to obtain the ecological nutrient soil product.

[0014] Further, in step (1), the heavy metal species in the iron tailings are adjusted: when the content of lead and cadmium is high, phosphorus ore powder is preferred; when the content of arsenic and chromium is high, humic acid is preferred; when there is complex heavy metal pollution, a stabilizer composed of humic acid and zeolite powder (mass ratio 1:1) is selected.

[0015] Further, 0.5-1.2 parts by weight of biological bacteria are added in the wet mixing process in step (3) to improve the nutrient soil nutrient conversion efficiency and heavy metal tolerance, wherein the biological bacteria are a Bacillus subtilis, a phosphorus solubilizing bacteria, and a heavy metal tolerant bacteria compound system.

[0016] Further, the curing parameters are adjusted according to the iron tailings addition amount in step (4): when the iron tailings account for ≥70%, the curing temperature is controlled at 25-32℃, and the curing time is extended to 8-10d; when the iron tailings account for ≤50%, the curing temperature is 22-28℃, and the curing time is 5-7d, to ensure the structural stability.

[0017] Further, natural airing combined with ventilation is adopted in the later curing stage of step (4) in the 7th-10th day to control the moisture content of the finished product at 15-20%, facilitating storage and transportation.

[0018] In the preparation process, the combined pretreatment process of "magnetic separation impurity removal + chemical stabilization" effectively removes impurities and reduces the activity of heavy metals; the geopolymer activation step ensures sufficient alkali activation reaction; the mixed stirring and gradient curing process (which can adjust the parameters according to the iron tailings addition amount) ensures that the nutrient soil has stable structure and performance within a wide range of mixing ratios, and the overall process is simple and easy to operate, suitable for large-scale production.

[0019] Compared with the prior art, the beneficial effects of the present application are: 1. wide and flexible consumption amount: the iron tailings account for 40-80 parts by weight, and the mixing ratio can be flexibly adjusted according to the regional iron tailings reserves and application scene requirements, the single batch consumption amount is much higher than that of the prior art, which can quickly digest different sizes of iron tailings accumulation and solve the solid waste disposal pressure; the geopolymer cementing system selects industrial solid waste precursors, and the comprehensive utilization rate of solid waste is more than 90%; 2. significant heavy metal stabilization effect: through the triple synergistic effect of "magnetic separation + chemical stabilization + geopolymer wrapping", the heavy metal leaching amount meets the GB 15618-2018 standard, wherein the lead and cadmium leaching amounts are lower than the detection limit, the arsenic and chromium leaching amounts are ≤0.1mg / L, there is no secondary pollution risk, and the ecological safety is high; 3. strong physicochemical property adaptability: the pore structure formed by the cooperation of geopolymer and iron tailings has a porosity of 35-50%, effectively improving the iron tailings hardening problem, a water retention rate ≥65%, and a pH value stable in the suitable range of 6.0-7.8, which can meet the growth needs of crops such as wheat and corn, ecological restoration pioneer plants such as alfalfa, sea buckthorn, and rye grass, and garden green plants; 4. Low cost and wide application: the raw material is mainly iron tailings, which is easy to obtain and low in price. The preparation process is simple, the ratio is flexible, and the cost is only 40-65% of that of traditional ecological restoration soil after large-scale production. It can be widely used in farmland improvement, landscaping, mine re-greening, slope ecological protection, and contaminated soil improvement, etc., with significant environmental, economic and social benefits. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below clearly and completely. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0021] In the following examples, the test materials and reagents used, unless otherwise specified, can be obtained commercially. If a specific technique or condition is not specified in the examples, it can be performed according to the technique or condition described in the literature in the art or according to the product manual. EMBODIMENT

[0022] The present embodiment provides a wide-ratio ecological nutrient soil based on geopolymer modified iron tailings (iron tailings account for 40 parts).

[0023] 1. Raw material ratio (weight parts): iron tailings 40 parts (150 mesh, SiO2 content 58%, Al2O3 content 10%, Al2O3 content 22%, water content 4%, pH value 7.5), geopolymer cementing system 25 parts (alkali activator: sodium hydroxide + water glass = 1:4, modulus 2.2; precursor: fly ash + slag = 1:1, active SiO2 + Al2O3 content 78%), organic nutrient component 15 parts (matured straw + biochar = 1:1, organic matter content 48%), functional regulator 3 parts (water retention agent + slow-release fertilizer + phosphate rock powder + wood ash = 1:1:1:1), water 7 parts; 2. Preparation steps: (1) The iron tailings are dried to a water content of 4%, crushed to 150 mesh, and then 1.5% of phosphate rock powder is added after magnetic separation and stirring. After uniform stirring, it is left for 36 hours. The matured straw and biochar are crushed to a particle size of ≤2 mm; (2) Mix the alkali activator and the precursor, and activate for 20 minutes; (3) Dry mix the iron tailings and the organic nutrient component for 10 minutes, then add the geopolymer cementing system, water, and 1.0 parts of bio-inoculant, and wet mix at 400 r / min for 25 minutes; (4) Curing at 25°C and 75% humidity for 6 days, with the first 3 days being sealed, and the last 3 days being turned over once a day and ventilated; (5) The crushed product is passed through a 10-mesh sieve to obtain the finished product.

[0024] 3. Performance detection: The prepared ecological nutrient soil in this embodiment has a porosity of 48%, a water retention rate of 75%, a pH value of 7.2, an organic matter content of 10.5%, a heavy metal (lead, cadmium, arsenic) leaching amount lower than the detection limit, a wheat germination rate of 97%, and a yield increase of 15% compared with ordinary soil. Example

[0025] This embodiment provides a wide-proportion ecological nutrient soil based on geopolymer modified iron tailings (iron tailings account for 60 parts).

[0026] 1. Raw material proportioning (weight parts): iron tailings 60 parts (180 mesh, SiO2 content 55%, Al2O3 content 9%, Fe2O3 content 25%, water content 3%, pH value 8.0), geopolymer cementitious system 18 parts (alkali activator: sodium hydroxide + water glass = 1:5, modulus 2.5; precursor: metakaolin + fly ash = 1:2, active SiO2 + Al2O3 content 82%), organic nutrient component 10 parts (humus + livestock and poultry manure compost = 2:1, organic matter content 46%), functional regulator 4 parts (water retention agent + slow-release fertilizer + humic acid + potassium dihydrogen phosphate = 2:1:1:1), water 6 parts; 2. Preparation steps: same as example 1, 2% humic acid is added after magnetic separation, stirring is uniform, and standing is 40 h, and the curing time is 7 d; 3. Performance detection: The prepared ecological nutrient soil in this embodiment has a porosity of 45%, a water retention rate of 72%, a pH value of 7.5, an organic matter content of 8.8%, and a heavy metal leaching amount that meets the standard. It is used for planting roses in landscaping, and the survival rate is 96%, and the flowering amount is increased by 20% compared with ordinary nutrient soil. Example

[0027] This embodiment provides a wide-proportion ecological nutrient soil based on geopolymer modified iron tailings (iron tailings account for 80 parts).

[0028] 1. Raw material proportioning (weight parts): iron tailings 80 parts (200 mesh, SiO2 content 50%, Al2O3 content 8%, Fe2O3 content 28%, water content 5%, pH value 8.5), geopolymer cementitious system 10 parts (alkali activator: sodium hydroxide + water glass = 1:6, modulus 2.8; precursor: slag + metakaolin = 3:1, active SiO2 + Al2O3 content 76%), organic nutrient component 5 parts (biochar + composted straw = 1:1, organic matter content 45%), functional regulator 6 parts (water retention agent + slow-release fertilizer + humic acid + zeolite powder + wood ash = 2:1:0.5:0.5:1), water 9 parts; 2. Preparation step: add 3% humic acid + zeolite powder compound stabilizer (mass ratio 1:1) after magnetic separation and impurity removal, stir uniformly, and stand for 48 h; the curing temperature is 28 DEG C, and the curing time is 10 d; 3. Performance detection: through detection, the porosity of the ecological nutrient soil prepared in the embodiment is 38%, the water retention rate is 68%, the pH value is 7.8, the organic matter content is 6.5%, the heavy metal leaching amount meets the standard, and the germination rate is 94% when the ecological nutrient soil is used for planting alfalfa and sea buckthorn in mine re-greening, the coverage rate is increased by 40% compared with ordinary re-greening soil, and the anti-scouring capacity is increased by 35%.

[0029] The core innovation of the present application is to break through the double bottleneck of consumption amount and ratio adaptability of traditional iron tailings utilization, to take 40-80 parts by weight of iron tailings as the core raw material, and to utilize the triple action of the geopolymer cementing system: first, to build a nutrient soil stable skeleton through a three-dimensional network structure, to break the iron tailings caking characteristics, to optimize the pore structure, and to provide sufficient space for plant root growth; second, to solidify heavy metals through physical wrapping, chemical adsorption and chemical bonding, to block their migration and diffusion path, and to reduce pollution risk; third, the cementing system ratio can be flexibly adjusted according to the amount of iron tailings added, to ensure the stability of the nutrient soil performance under different ratios; and then, combined with the nutrient supply function of the organic nutrient component and the performance optimization effect of the functional regulator, through scientific ratio and process control, to prepare the ecological nutrient soil which has the characteristics of flexible consumption, heavy metal stabilization and multi-scene adaptability.

[0030] The SiO2 and Al2O3 content of iron tailings as the core raw material is rich, which can have a synergistic alkali activation reaction with the geopolymer cementing system, ensuring the stability of the nutrient soil structure and realizing wide-range consumption (40-80 parts); the geopolymer cementing system selects fly ash, slag and other industrial solid wastes as aluminosilicate precursors, further improving the comprehensive utilization efficiency of solid wastes and realizing "waste treatment with waste". The organic nutrient component provides organic matter, nitrogen, phosphorus, potassium and other nutrients required for plant growth, and improves soil aggregation; the functional regulator optimizes the water retention, fertilizer efficiency release and pH value, and at the same time, strengthens the heavy metal stabilization effect, ensuring the ecological safety and scene adaptability of the nutrient soil.

[0031] In the preparation process, the combined pretreatment process of "magnetic separation and impurity removal + chemical stabilization" effectively removes impurities and reduces the activity of heavy metals; the geopolymer activation step ensures sufficient alkali activation reaction; the mixing and stirring and gradient curing process (the parameters can be adjusted according to the amount of iron tailings added) ensure that the nutrient soil has stable structure and performance in a wide range of ratios, and the overall process is simple and easy to operate, suitable for large-scale production.

[0032] The embodiments of the present application are disclosed above, but not limited to, the preferred embodiments, and those skilled in the art can make different deductions and changes according to the above embodiments, and the different deductions and changes should be within the protection scope of the present application as long as they do not deviate from the spirit of the present application.

Claims

1. A wide-proportion ecological nutrient soil based on geopolymer modified iron tailings, characterized in that, The raw materials include the following components by weight: iron tailings 40-80 parts, geopolymer cementitious system 10-25 parts, organic nutrient component 5-15 parts, functional regulator 2-6 parts, and water 5-9 parts.

2. The wide-proportion ecological nutrient soil based on the geopolymer-modified iron tailings according to claim 1, characterized in that: The iron tailings have a particle size of 100-200 mesh, a SiO2 content of ≥50%, an Al2O3 content of ≥8%, an Fe2O3 content of 15-30%, a water content of ≤5%, and a pH value of 6.5-9.

0.

3. The wide-proportion ecological nutrient soil based on the geopolymer-modified iron tailings according to claim 1, characterized in that: The geopolymer cementitious system is compounded from an alkali activator and an aluminosilicate precursor at a mass ratio of 1:2.5-1:

5. The alkali activator is a mixed system of sodium hydroxide and water glass at a mass ratio of 1:3-1:6, and the water glass has a modulus of 2.0-2.

8. The aluminosilicate precursor is a mixture of one or more of fly ash, slag, and metakaolin, and the active SiO2+Al2O3 content in the aluminosilicate precursor is ≥75%.

4. The wide-proportion ecological soil based on geopolymer-modified iron tailings according to claim 1, characterized in that: The organic nutrient component is a mixture of one or more of decomposed straw, humus soil, biochar, and decomposed manure, and has an organic matter content of ≥45% and a particle size of ≤3 mm.

5. The wide-proportion ecological soil based on geopolymer-modified iron tailings according to claim 1, characterized in that: The functional regulator is compounded from a water-retaining agent, slow-release fertilizer, heavy metal stabilizer, and pH regulator at a mass ratio of 1:1:1:1-2:1:1:

1. The water-retaining agent is a polyacrylamide water-retaining agent. The slow-release fertilizer is a urea-formaldehyde resin coated compound fertilizer. The heavy metal stabilizer is humic acid, zeolite powder, or phosphorite powder. The pH regulator is wood ash or potassium dihydrogen phosphate.

6. A method for preparing a wide-range ecological soil amendment based on geopolymer-modified iron tailings according to any one of claims 1 to 5, characterized in that, The method includes the following steps: (1) The raw materials are treated by a combined process of "magnetic separation and chemical stabilization": the iron tailings are dried to a water content of ≤5%, crushed, and then sieved through a 100-200 mesh sieve, the iron magnetic impurities and part of the heavy metal sulfides are removed by magnetic separation, 1-3% of the iron tailings by mass of a heavy metal stabilizer is added, the mixture is stirred uniformly, and then is left to stand for 24-48 h to reduce the activity of heavy metals through adsorption and chelation; the organic nutrient component is crushed to a particle size of ≤3 mm and is ready for use; (2) The geopolymer cementitious system is prepared: the alkali activator and the aluminosilicate precursor are mixed in proportion, stirred uniformly, and then left to stand for 15-30 min to ensure that the alkali activation is fully released, and is ready for use; (3) Mixing and stirring: the pretreated iron tailings and the organic nutrient component are added to a stirrer, dry mixing is performed for 8-15 min until they are uniformly mixed; the geopolymer cementitious system and water are then added, wet mixing is performed for 20-30 min until the material is loose and free of lumps, and the stirring speed is controlled at 350-500 r / min; (4) Activation and curing: the mixed material is spread on a curing site, the environmental temperature is controlled at 22-32℃, the humidity is controlled at 65-85%, and the material is cured for 5-10 d; the material is cured in a closed environment for the first 3 d, is turned over once a day for the next 7 d, and is gradually ventilated and dehumidified to ensure uniform curing and stable structure; (5) Product processing: after curing, the material is crushed, sieved through an 8-10 mesh sieve, and a small amount of lumps and impurities are removed to obtain the finished ecological nutrient soil.

7. The method for preparing a wide-proportion ecological nutrient soil based on geopolymer-modified iron tailings according to claim 6, characterized in that, In step (1), adjust according to the heavy metal species of iron tailings: when the content of lead and cadmium is high, prefer to use phosphate rock powder; when the content of arsenic and chromium is high, prefer to use humic acid; when there is complex heavy metal pollution, use humic acid and zeolite powder compound stabilizer.

8. The method for preparing a wide-proportion ecological nutrient soil based on geopolymer modified iron tailings according to claim 6, characterized in that: In step (3), 0.5-1.2 parts by weight of biological bacteria are added in the wet mixing process to improve the nutrient conversion efficiency and heavy metal tolerance of the nutrient soil, wherein the biological bacteria are a compound system of bacillus subtilis, phosphorus solubilizing bacteria and heavy metal tolerant bacteria.

9. The method for preparing a wide-proportion ecological soil based on geopolymer modified iron tailings according to claim 6, characterized in that, In step (4), the curing parameters are adjusted according to the addition amount of iron tailings: When the proportion of iron tailings is greater than or equal to 70%, the curing temperature is controlled at 25-32℃, and the curing time is extended to 8-10d; When the proportion of iron tailings is less than or equal to 50%, the curing temperature is 22-28℃, and the curing time is 5-7d to ensure the stability of the structure.

10. The method for preparing a wide-proportion ecological nutrient soil based on geopolymer-modified iron tailings according to claim 6, characterized in that: In the later stage of step (4), natural airing combined with ventilation is adopted in the 7th-10th day after curing to control the moisture content of the finished product at 15-20% for easy storage and transportation.