Coal gangue-based artificial soil as well as preparation method and application thereof

Abstract

The invention provides coal gangue-based artificial soil as well as a preparation method and application thereof. The preparation method of the coal gangue-based artificial soil comprises the following steps: S1, modifying coal gangue by adopting a solution containing citric acid and ethylenediamine tetraacetic acid to obtain modified coal gangue; s2, preparing the modified coal gangue into artificial soil. According to the invention, the citric acid can dissolve carbonate in the coal gangue, the released carbonate can be combined with heavy metals, and citrate ions and ferric ions can form a complex to destroy the outer layer of ferric oxide of the heavy metals; ethylenediamine tetraacetic acid can permeate into mineral lattices of the coal gangue, lattice bound state heavy metal is released through octahedral Al-O bond breakage, the ethylenediamine tetraacetic acid can capture heavy metal combined with citric acid, a more stable heavy metal complex is formed, the heavy metal complex carries strong negative charges, and the heavy metal complex can be separated from the coal gangue. And electrostatic repulsion can be generated on the surface of the coal gangue with negative electricity, so that the heavy metal removal effect is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of planting substrate, and particularly relates to a coal gangue-based artificial soil and a preparation method and application thereof. BACKGROUND

[0002] Coal gangue is a solid waste discharged in the process of coal mining and coal washing, and is a black gray rock with low carbon content and high hardness associated with coal seams in the process of coal formation. The coal gangue includes tunneling gangue in the process of tunneling, gangue mined from the roof, floor and interlayer in the process of mining, and washing gangue picked in the process of coal washing. The main components of the coal gangue are aluminum oxide, silicon dioxide and iron oxide, and also contain a small amount of carbonate and other substances. The coal gangue accounts for about 15% of the total amount of industrial solid waste in China, and the annual discharge amount exceeds 700 million tons. The coal gangue has high hardness and low porosity, and directly used as soil substrate will result in poor air permeability; the pH value is high, and the trace heavy metals contained in the coal gangue are easy to be leached by rainwater to pollute the environment.

[0003] The pyrite in the coal gangue is easy to be oxidized to generate sulfuric acid to acidify the soil, and the heavy metals in the coal gangue will exchange ions with calcium ions in the soil to reduce the soil fertility and aggravate the heavy metal pollution, thereby endangering the health of human body and environment.

[0004] In the related art, a lemon acid solution is used to leach the coal gangue to remove the heavy metals in the coal gangue. However, the removal effect of the heavy metal ions in the coal gangue by using the method needs to be further improved. SUMMARY

[0005] The present application provides a coal gangue-based artificial soil and a preparation method and application thereof, so as to further improve the removal effect of the heavy metal ions in the coal gangue.

[0006] The present application provides a preparation method of a coal gangue-based artificial soil, which comprises the following steps: S1. A solution containing lemon acid and ethylenediaminetetraacetic acid (EDTA) is used to modify the coal gangue to obtain modified coal gangue; S2. The modified coal gangue is made into artificial soil.

[0007] In an embodiment of the present application, in the solution of step S1, the molar ratio of the lemon acid to the ethylenediaminetetraacetic acid is 0.45-0.50:0.075-0.1.

[0008] In an embodiment of the present application, in step S1, the mass ratio of the solution to the coal gangue is 3.75-5:1.

[0009] In an embodiment of the present application, in step S1, the modification process comprises: the coal gangue is added into the solution, oscillated, filtered, washed, and dried to obtain the modified coal gangue.

[0010] In an embodiment of the present application, before the modification treatment in step S1, the coal gangue is pretreated.

[0011] In an embodiment of the present application, the pretreatment in step S1 includes: crushing and ball milling the coal gangue.

[0012] In an embodiment of the present application, in step S2, the modified coal gangue is made into artificial soil by mixing the modified coal gangue with organic matter, heavy metal adsorbent, pH regulator, water-retaining agent and microbial agent, fermentation, and post-treatment.

[0013] In an embodiment of the present application, in step S2, the mass ratio of the modified coal gangue, the organic matter, the heavy metal adsorbent, the pH regulator, the water-retaining agent and the microbial agent is 60-70:15-25:8-10:2-4:0.2-0.5:2.5-2.8.

[0014] The present application also provides a coal gangue-based artificial soil prepared according to the method as described above.

[0015] The present application also provides the application of the coal gangue-based artificial soil as described above in ecological restoration and landscaping.

[0016] The present application has the following advantages: In the present application, the citric acid can dissolve the carbonates in the coal gangue, and the released carbonates can combine with the heavy metals, and the citrate ions can form a complex with the trivalent iron ions, destroying the outer layer of the oxidized iron of the heavy metals; the ethylenediaminetetraacetic acid can penetrate into the mineral crystal lattice of the coal gangue, releasing the lattice-bound heavy metals by breaking the octahedral Al-O bond, and the ethylenediaminetetraacetic acid can take away the heavy metals combined with the citric acid, forming a more stable heavy metal complex with strong negative charge, which can produce electrostatic repulsion with the negatively charged surface of the coal gangue, thereby improving the removal effect of the heavy metals. BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawings incorporated into the specification and forming a part thereof, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application. It is to be expressly understood, however, that the drawings are only for the purpose of illustration and are not intended as a definition of the limits of the application. From the drawings, it can be seen that other drawings can be derived by those skilled in the art without paying creative labor.

[0018] In the drawings: Figure 1 The physical picture of the artificial soil provided for Embodiment 1 of the present application. DETAILED DESCRIPTION

[0019] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0020] An embodiment of the present application provides a preparation method of a coal gangue-based artificial soil, comprising the following steps: S1. modifying coal gangue by using a solution containing citric acid and ethylenediaminetetraacetic acid to obtain modified coal gangue; S2. preparing artificial soil from the modified coal gangue.

[0021] In the present application, by compounding a specific acid (citric acid) and ethylenediaminetetraacetic acid, the removal effect of heavy metals can be improved through the synergistic effect of the two, wherein the carbonates in the coal gangue can be dissolved by the citric acid, and the released carbonates can be combined with heavy metals, and the citrate ions can form a complex with the trivalent iron ions to destroy the outer layer of iron oxide of the heavy metals; the ethylenediaminetetraacetic acid can penetrate into the mineral crystal lattice of the coal gangue to release the lattice-bound heavy metals through the rupture of the octahedral Al-O bond, and the ethylenediaminetetraacetic acid can also capture the heavy metals combined with the citric acid to form a more stable heavy metal complex, which has a strong negative charge and can produce electrostatic repulsion with the surface of the coal gangue with a negative charge, thereby improving the removal effect of heavy metals.

[0022] In an embodiment of the present application, in the solution of step S1, the molar ratio of citric acid to ethylenediaminetetraacetic acid is 0.45-0.50:0.075-0.1, preferably 0.48-0.5:8-10.

[0023] In an embodiment of the present application, in the solution of step S1, the concentration of citric acid is 0.45-0.50 mol / L, preferably 0.48-0.5 mol / L.

[0024] In an embodiment of the present application, in step S1, the mass ratio of the solution to the coal gangue is 3.75-5:1, preferably 4-5:1.

[0025] In an embodiment of the present application, in step S1, the modification treatment comprises: adding the coal gangue into the solution, oscillating, suction filtering, washing, and drying to obtain the modified coal gangue.

[0026] In an embodiment of the present application, in step S1, oscillation is performed at a temperature of 20-30℃, preferably at a temperature of 24-30℃.

[0027] In an embodiment of the present application, in step S1, the oscillation time is 2-4 hours, preferably 2.5-4 hours.

[0028] In an embodiment of the present application, in step S1, the washing is until the pH is greater than 6.0.

[0029] In an embodiment of the present application, in step S1, the drying temperature is 100-110 DEG C, preferably 104-110 DEG C.

[0030] In an embodiment of the present application, in step S1, the coal gangue is pretreated before the modification treatment.

[0031] In an embodiment of the present application, in step S1, the pretreatment includes: crushing the coal gangue and then ball milling.

[0032] In an embodiment of the present application, in step S1, the crushing is to a particle size of less than or equal to 5 mm.

[0033] In an embodiment of the present application, in step S1, the ball milling is to a particle size of 40-50 microns.

[0034] In an embodiment of the present application, in step S2, the modified coal gangue is made into artificial soil by mixing the modified coal gangue with organic matter, heavy metal adsorbent, pH regulator, water retaining agent and bacterial agent, fermentation and post-treatment.

[0035] In an embodiment of the present application, in step S2, the mass ratio of the modified coal gangue, organic matter, heavy metal adsorbent, pH regulator, water retaining agent and bacterial agent is 60-70:15-25:8-10:2-4:0.2-0.5:2.5-2.8, preferably 65-70:16-25:9-10:3-4:0.3-0.5:2.6-2.8.

[0036] In the present application, the water retaining agent can lock the water in the soil, the heavy metal adsorbent can reduce the content of harmful ingredients in the soil, the pH regulator can adjust the soil acidity and alkalinity to be more suitable for plant growth, and the organic matter and bacterial agent can increase the soil fertility to create favorable conditions for plant growth.

[0037] In the present application, the organic matter is not limited and can be exemplified by substances such as matured cow dung, kitchen waste, biogas residue, traditional Chinese medicine residue, mushroom dregs, and algal sludge.

[0038] In an embodiment of the present application, in step S2, the heavy metal adsorbent is selected from at least one of bentonite, sepiolite, manganese oxide zeolite and biochar.

[0039] In an embodiment of the present application, in step S2, the pH regulator is selected from at least one of sulfur powder, dihydrogen phosphate, humic acid and citric acid.

[0040] In an embodiment of the present application, in step S2, the water-retaining agent is selected from at least one of polyacrylamide, regenerated sponge particles and cellulose gel.

[0041] In an embodiment of the present application, in step S2, the bacterial agent comprises Bacillus mucilaginosus spore powder and Bacillus subtilis fermentation liquor.

[0042] In an embodiment of the present application, in step S2, the mass ratio of the Bacillus mucilaginosus spore powder to the Bacillus subtilis fermentation liquor is 6.5-7.5:2.5-3.5.

[0043] In an embodiment of the present application, in step S2, the fermentation comprises: first fermentation at a temperature of 53-57℃ for 2-4 days, and then fermentation at a temperature of 39-41℃ for 11-13 days.

[0044] In the present application, the combination of three-stage activation physical crushing, chemical modification and two-stage biological fermentation can further improve the soil fertility.

[0045] In an embodiment of the present application, in step S2, during the fermentation process, the moisture content is 50%-55%, preferably 52%-55%; and the aeration amount is 0.4-0.6 L / (min·kg), preferably 0.45-0.6 L / (min·kg).

[0046] In an embodiment of the present application, in step S2, the post-processing comprises: spreading and airing to a moisture content of 25%-32%, preferably 26%-32%; and sieving.

[0047] In an embodiment of the present application, in step S2, the mesh size of the sieve is 1.5-2.5 mm, preferably 1.8-2.1 mm.

[0048] Another embodiment of the present application further provides a coal gangue-based artificial soil prepared according to the method as described above.

[0049] Another embodiment of the present application further provides application of the coal gangue-based artificial soil as described above in ecological restoration and landscaping.

[0050] In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on that a person having ordinary skill in the art can realize, when the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0051] Example 1 S1. Preparation of modified coal gangue The coal gangue was coarsely crushed to a particle size of less than or equal to 5 mm by using a jaw crusher to obtain a primary crushed coal gangue powder; Take 500 g of the primary crushed coal gangue powder and place it in a ball mill tank to grind to a particle size of 45 μm, obtaining the coal gangue powder; A solution containing 0.5 mol / L citric acid and 0.1 mol / L EDTA is prepared, and the coal gangue powder is added to the solution according to a mass ratio of 5:1, and oscillated at 25°C for 4 h; The filtrate is washed with deionized water until the pH is greater than 6.0, and then dried in an oven at 105°C, obtaining the modified coal gangue; S2. Preparation of artificial soil The modified coal gangue 65 parts, matured cow dung 20 parts, bentonite 10 parts, sulfur powder 2 parts, polyacrylamide 0.5 parts and microbial agent (consisting of Bacillus mucilaginosus spore powder and Bacillus subtilis fermentation broth according to a mass ratio of 7:3, both of which are commercially available products) 2.5 parts are placed in a mixer and stirred for 15 min until uniform, and then transferred to a compost reactor for fermentation for 15 days, wherein the fermentation temperature is 55°C for the first 3 days and 40°C for the last 12 days, the moisture content is controlled at 55% throughout the fermentation process, and the air flow (specifically air) is controlled at 0.5 L / (min·kg) throughout the fermentation process. After fermentation, spread out to air dry to a moisture content of 32%, remove undecomposed impurities through a 2 mm sieve, and obtain the artificial soil (as shown in Figure 1 ).

[0052] Example 2 S1. Preparation of modified coal gangue The coal gangue is coarsely crushed to a particle size of less than or equal to 5 mm using a jaw crusher, obtaining the primary crushed coal gangue powder; Take 500 g of the primary crushed coal gangue powder and place it in a ball mill tank to grind to a particle size of 45 μm, obtaining the coal gangue powder; A solution containing 0.45 mol / L citric acid and 0.075 mol / L EDTA is prepared, and the coal gangue powder is added to the solution according to a mass ratio of 3.75:1, and oscillated at 25°C for 4 h; The filtrate is washed with deionized water until the pH is greater than 6.0, and then dried in an oven at 105°C, obtaining the modified coal gangue; S2. Preparation of artificial soil Put 70 parts of modified coal gangue, 15 parts of algal sludge, 8 parts of biochar, 4 parts of ammonium dihydrogen phosphate, 0.2 parts of recycled sponge particles (commercially available), and 2.8 parts of microbial agent (consisting of Bacillus mucilaginosus spore powder and Bacillus subtilis fermentation broth in a mass ratio of 7:3, both of which are commercially available) into a mixer, stir for 15 min until uniform, and transfer into a compost reactor for fermentation for 15 days. During the first 3 days, the fermentation temperature is 55°C, and during the last 12 days, the fermentation temperature is 40°C. During the entire fermentation process, the moisture content is controlled at 55%, and the ventilation amount (specifically air) is controlled at 0.5 L / (min·kg). After fermentation, spread out to air dry until the moisture content is 25%, pass through a 2 mm sieve to remove undecomposed impurities, and prepare artificial soil.

[0053] Example 3 S1. Preparation of modified coal gangue Coarsely crush the coal gangue to a particle size of less than or equal to 5 mm using a jaw crusher to obtain primary crushed coal gangue powder; Take 500 g of the primary crushed coal gangue powder and place it in a ball mill jar for ball milling to a particle size of 45 μm to obtain coal gangue powder; Prepare a solution containing 0.47 mol / L citric acid and 0.08 mol / L EDTA, and add the coal gangue powder to the solution at a solution to coal gangue powder mass ratio of 4:1, and shake at 25°C for 3 h; Filter and wash the filtrate with deionized water until the pH is >6.0, then place it in an oven at 105°C to dry, to obtain modified coal gangue; S2. Preparation of artificial soil Put 67.5 parts of modified coal gangue, 17.5 parts of mushroom dregs, 9 parts of sepiolite, 3 parts of humic acid, 0.3 parts of cellulose gel, and 2.7 parts of microbial agent (consisting of Bacillus mucilaginosus spore powder and Bacillus subtilis fermentation broth in a mass ratio of 7:3, both of which are commercially available) into a mixer, stir for 15 min until uniform, and transfer into a compost reactor for fermentation for 15 days. During the first 3 days, the fermentation temperature is 55°C, and during the last 12 days, the fermentation temperature is 40°C. During the entire fermentation process, the moisture content is controlled at 55%, and the ventilation amount (specifically air) is controlled at 0.5 L / (min·kg). After fermentation, spread out to air dry until the moisture content is 30%, pass through a 2 mm sieve to remove undecomposed impurities, and prepare artificial soil.

[0054] Example 4 S1. Preparation of modified coal gangue Coarsely crush the coal gangue to a particle size of less than or equal to 5 mm using a jaw crusher to obtain primary crushed coal gangue powder; Take 500 g of the primary crushed coal gangue powder and place it in a ball mill jar for ball milling for 2 h to a particle size of 45 μm to obtain coal gangue powder; A solution containing 0.48 mol / L citric acid and 0.09 mol / L EDTA was prepared, and coal gangue powder was added to the solution at a mass ratio of 4.5:1, and oscillated at 25°C for 4h; The filtrate was washed with deionized water until the pH was >6.0, and then dried in an oven at 105°C to obtain modified coal gangue; S2. Preparation of artificial soil The modified coal gangue 66 parts, traditional Chinese medicine residues (commercially available) 19 parts, manganese oxide zeolite (commercially available) 10 parts, citric acid 2 parts, cellulose gel 0.5 parts, and microbial agent (consisting of Bacillus mucilaginosus spore powder and Bacillus subtilis fermentation broth at a mass ratio of 7:3, both commercially available) 2.5 parts were placed in a mixer and stirred for 15 min until uniform, and then transferred to a compost reactor for fermentation for 15 days, wherein the fermentation temperature was 55°C for the first 3 days and 40°C for the last 12 days. During the entire fermentation process, the moisture content was controlled at 55%, and the air flow (specifically air) was controlled at 0.5 L / (min·kg). After fermentation, the mixture was spread out to dry to a moisture content of 28%, and then passed through a 2 mm sieve to remove undecomposed impurities, to obtain artificial soil.

[0055] Example 5 S1. Preparation of modified coal gangue The coal gangue was coarsely crushed to a particle size of less than or equal to 5 mm using a jaw crusher to obtain primary crushed coal gangue powder; 500 g of the primary crushed coal gangue powder was placed in a ball mill jar and ball milled for 2h to a particle size of 45 μm to obtain coal gangue powder; A solution containing 0.49 mol / L citric acid and 0.09 mol / L EDTA was prepared, and coal gangue powder was added to the solution at a mass ratio of 4.5:1, and oscillated at 25°C for 3.5h; The filtrate was washed with deionized water until the pH was >6.0, and then dried in an oven at 105°C to obtain modified coal gangue; S2. Preparation of artificial soil Put 60 parts of modified coal gangue, 25 parts of matured cow dung, 10 parts of bentonite, 2 parts of sulfur powder, 0.5 parts of polyacrylamide and 2.5 parts of microbial agent (consisting of Bacillus mucilaginosus spore powder and Bacillus subtilis fermentation broth in a mass ratio of 7:3, both of which are commercially available products) in a mixer, stir for 15 min until uniform, and transfer to a compost reactor for fermentation for 15 days, wherein the fermentation temperature is 55℃ for the first 3 days and 40℃ for the subsequent 12 days. During the entire fermentation process, the moisture content is controlled at 55%, and the air flow (specifically air) is controlled at 0.5 L / (min·kg). After fermentation, spread out to air dry until the moisture content is 32%, pass through a 2 mm sieve to remove undecomposed impurities, and obtain the artificial soil.

[0056] Comparative Example 1 The difference between this comparative example and Example 1 is that the coal gangue is not modified, i.e., the modified coal gangue in step S2 is replaced by coal gangue from the same source as in Example 1.

[0057] Comparative Example 2 The difference between this comparative example and Example 1 is that humic acid is used instead of citric acid.

[0058] Comparative Example 3 The difference between this comparative example and Example 1 is that oxalic acid is used instead of citric acid.

[0059] Comparative Example 4 The difference between this comparative example and Example 1 is that the solution does not contain citric acid, and the concentration of EDTA is 0.6 mol / L.

[0060] Comparative Example 5 The difference between this comparative example and Example 1 is that the solution does not contain EDTA, and the concentration of citric acid is 0.6 mol / L.

[0061] Test The artificial soil obtained in Examples 1-5 and Comparative Examples 1-4 was tested for germination rate. Specifically, each group of test samples was divided into 10 parts, each of which was filled into 10 pots of the same size. Standard ryegrass seeds were sown in 5 pots at a sowing density of 15 ryegrass seeds per pot, and small cabbage seeds were sown in the other 5 pots at a sowing density of 5 small cabbage seeds per pot. The light was on for 14 hours every day, and the photosynthetic photon flux was 20 μmol / s using LED plant growth lamps. Irrigation was performed every 3 days to maintain the soil moisture content at 30%. The germination rate was calculated on the 15th day (taking the sum of standard ryegrass seeds and small cabbage seeds as the base), and field soil (taken from Kunming University of Science and Technology in Wuhua District, Kunming City, Yunnan Province) was used as a reference. The results are shown in Table 1. 2 ​Cd content test was conducted on the artificial soil prepared according to the examples 1-5 and the comparative examples 1-4, specifically, each group of samples to be tested was placed in aqua regia, treated in water bath at 95℃ for 1h, and then diluted to 50mL, followed by centrifugation at 4000rmp / min for 10min, and then the supernatant was placed in an ICP spectrometer to detect the Cd content, thus the Cd content in the artificial soil was obtained, and the results are shown in Table 1. Cd content in the raw coal gangue used in the test examples 1-5 and the comparative examples 1-4 was tested, and then the Cd removal rate was calculated according to the formula Cd removal rate, Cd content in the coal gangue, unit: mg / kg, Cd content in the artificial soil, and the results are shown in Table 1.

[0062] Table 1 Test results

[0063] As can be seen from Table 1, compared with the comparative example 1 (without modification of the coal gangue), the germination rate of the example 1 (modification of the coal gangue) is significantly improved, the Cd content is significantly reduced, and the Cd removal rate is significantly improved. The results show that, in the present application, by modifying the coal gangue, the content of harmful components such as heavy metals in the coal gangue can be significantly reduced, the soil fertility can be improved, and thus the germination rate can be improved.

[0064] As can be seen from Table 1, compared with the comparative example 2 (using humic acid instead of citric acid), the comparative example 3 (using oxalic acid instead of citric acid), the comparative example 4 (without citric acid in the solution, and the concentration of EDTA is 0.6mol / L), and the comparative example 5 (without EDTA in the solution, and the concentration of citric acid is 0.6mol / L), the Cd removal rate of the example 1 is significantly improved. The results show that, in the present application, by compounding a specific acid (citric acid) and ethylenediaminetetraacetic acid, the removal effect of heavy metals can be improved through the synergistic effect of the two, wherein the citric acid can dissolve the carbonate in the coal gangue, and the released carbonate can combine with the heavy metals, and the citrate ion can form a complex with the trivalent iron ion, thereby destroying the outer layer of the heavy metal oxide; the ethylenediaminetetraacetic acid can penetrate into the mineral crystal lattice of the coal gangue, release the lattice-bound heavy metals through the rupture of the octahedral Al-O bond, and the ethylenediaminetetraacetic acid can capture the heavy metals combined with the citric acid to form a more stable heavy metal complex, which has strong negative charge and can produce electrostatic repulsion with the negatively charged surface of the coal gangue, thereby improving the removal effect of heavy metals.

[0065] ​The above embodiments are only illustrative of the principles of the present application and its efficacy, and are not intended to limit the present application. Any modification or change made by any person skilled in the art without departing from the spirit and scope of the present application shall be covered by the claims of the present application.

Claims

1. A method for preparing a coal gangue-based artificial soil, characterized in that, The method comprises the following steps: S1. modifying coal gangue with a solution containing citric acid and ethylenediaminetetraacetic acid to obtain modified coal gangue; S2. preparing artificial soil from the modified coal gangue.

2. The method of claim 1, wherein the coal refuse-based artificial soil is prepared by mixing the coal refuse, the soil, and the water in a ratio of 1: 1: 0.5 to 1: 1:

1. In the solution of step S1, the molar ratio of citric acid to ethylenediaminetetraacetic acid is 0.45-0.50:0.075-0.

1.

3. The method of claim 1, wherein the coal refuse-based artificial soil is prepared by mixing the coal refuse, the soil, and the water in a ratio of 1: 1: 0.5 to 1: 1:

1. In step S1, the mass ratio of the solution to coal gangue is 3.75-5:

1.

4. The method of claim 1, wherein the coal refuse-based artificial soil is prepared by mixing the coal refuse, the soil, and the water in a ratio of 1: 1:

1. In step S1, the modification process comprises adding the coal gangue into the solution, oscillating, suction filtering, washing, drying, and obtaining the modified coal gangue.

5. The method of claim 1, wherein the coal refuse-based artificial soil is prepared by mixing the coal refuse, the soil, and the water in a ratio of 1: 1: 0.5 to 1: 1:

1. In step S1, the coal gangue is pretreated before the modification process.

6. The method of claim 5, wherein the coal refuse-based artificial soil is prepared by mixing the coal refuse, the soil, and the water in a ratio of 1 : 1 :

1. In step S1, the pretreatment comprises crushing and ball milling the coal gangue.

7. The method of claim 1, wherein the coal refuse-based artificial soil is prepared by mixing the coal refuse, the soil, and the water in a ratio of 1: 1:

1. In step S2, preparing artificial soil from the modified coal gangue comprises mixing the modified coal gangue with organic matter, heavy metal adsorbent, pH regulator, water-retaining agent, and bacterial agent, fermenting, and post-processing.

8. The method of claim 7, wherein the coal refuse-based artificial soil is prepared by mixing the coal refuse, the soil, and the water in a ratio of 1 : 1 :

1. In step S2, the mass ratio of the modified coal gangue, the organic matter, the heavy metal adsorbent, the pH regulator, the water-retaining agent, and the bacterial agent is 60-70:15-25:8-10:2-4:0.2-0.5:2.5-2.

8.

9. Coal gangue-based artificial soil prepared according to the method of any one of claims 1-8.

10. Application of the coal gangue-based artificial soil of claim 9 in ecological restoration and landscaping.

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