A porous artificial soil based on coal gangue, its preparation method and application

Abstract

This invention relates to a porous artificial soil based on coal gangue, its preparation method, and its applications. The method provided by this invention is environmentally friendly and does not involve heating reaction devices. The production conditions are mild, and the process control is precise, making it suitable for industrial production. The porous planting layer ecological substrate developed in this invention uses coal gangue as the main raw material, providing a reliable new approach for the comprehensive utilization of coal gangue. It can also improve soil, replace loess resources, and facilitate ecological restoration. Simultaneously, the porous planting layer ecological substrate possesses many of the functions of soil, including aggregation, porous water and fertilizer retention, and its organic matter, available phosphorus, total nitrogen, and available potassium levels meet the physical and chemical performance requirements of arable soil. It can not only replace soil but also act as a soil conditioner to improve soil conditions.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization and ecological restoration technology of coal gangue, specifically relating to a preparation technology of porous artificial soil based on coal gangue that can be produced industrially. Background Technology

[0002] Coal gangue is a solid waste generated during coal mining and washing. Its main components include carbonaceous shale, argillaceous shale, and sandstone, with small amounts of coal and inorganic minerals. Its chemical composition is complex, typically containing elements such as silicon, aluminum, iron, calcium, and magnesium, as well as small amounts of sulfur and phosphorus.

[0003] Coal gangue, as a waste product, leads to land occupation and environmental pollution. To turn waste into treasure, existing technologies mainly utilize coal gangue in the following ways: as building materials, it can be used to produce bricks, cement, ceramsite, and other building materials; for landfilling and reclamation, it can be used to fill subsidence areas or reclaim land; and as a chemical raw material, it can be used to extract elements such as aluminum and silicon, or to produce chemical products.

[0004] In existing technologies, there are techniques for preparing artificial soil based on coal gangue for plant cultivation. However, a prominent technical problem with this type of artificial soil is that it needs to have excellent permeability, meaning that the soil particles must be uniform and of appropriate size to maintain good aeration and prevent rapid soil loss after watering. Furthermore, the processing and preparation of this artificial soil requires relatively mild conditions. If harsh processing conditions are required, it will inevitably lead to increased costs and is not suitable for industrial production. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a technology for the comprehensive utilization of coal gangue under mild conditions that is suitable for use as artificial soil.

[0006] To achieve the above objectives, the present invention provides a method for preparing porous artificial soil based on coal gangue, comprising the following steps:

[0007] Step 1: Crush 100 portions of gangue to a size between 13mm and 50mm for later use;

[0008] Step 2: Add 2 to 5 parts of slag and 1 to 3 parts of fly ash to the gangue obtained in Step 1 and grind it to 120 to 140 mesh. Add 0.5 to 2 parts of a regulator and stir evenly. The regulator is desulfurized gypsum, which has undergone drying pretreatment.

[0009] Step 3: Dilute 2.5 to 6 parts of foaming agent and 3.0 to 8 parts of foam stabilizer with water and add them to the material in Step 2 and mix evenly; the foaming agent is selected from alkyl glycosides, animal and plant protein products and polysaccharides, and the proportion of animal and plant protein products and polysaccharides in the foaming agent is 10% to 20%; the foam stabilizer is at least one of the following substances: starch, polytetrafluoroethylene, phosphorylated starch, starch xanthate, grafted cellulose, carboxymethylated cellulose, hydroxypropylated cellulose;

[0010] Step 4: After drying the well-mixed slurry, we obtain porous artificial soil based on coal gangue.

[0011] Preferably, the animal or plant protein product is at least one of the following substances: soy protein, silk protein, and gluten;

[0012] The polysaccharide is at least one of the following substances: pectin, alginate, or chitosan.

[0013] Preferably, the desulfurized gypsum undergoes a drying pretreatment process of drying at 150°C for 1 hour before use;

[0014] Dilute the foaming agent and foam stabilizer with water 10 to 25 times and then add them to the material in step 2 and mix well.

[0015] Preferably, the slag and fly ash are industrial solid waste generated from industrial production, with a pH value of less than 8.5 and a heavy metal content that meets the requirements of GB15618-2018 for the risk control of agricultural land.

[0016] Preferably, the gangue raw material is gangue excavated or washed gangue.

[0017] The present invention provides a porous artificial soil based on coal gangue, which is obtained by any of the preparation methods described herein.

[0018] Preferably, the electrical conductivity EC = 0.23256 ± 2.52 dS / m; the water-soluble salt content is 1.47 g / kg.

[0019] Preferably, the porous artificial soil based on coal gangue has a water retention rate of 37%, a thermal insulation performance of 8.1℃, and a loose density of 0.43 g / cm³. 3 The soil loss rate was 1.27%.

[0020] Preferably, a foaming maintenance agent is used during the planting process. The foaming maintenance agent is applied directly to the surface of the artificial soil by spraying, or the soil is tilled in the gaps between the plants to mix the foaming maintenance agent into the artificial soil. The foaming maintenance agent is a combination of alkyl glycosides, animal and plant protein products and polysaccharides. The composition is obtained by soaking alkyl glycosides and animal and plant protein products in a polysaccharide solution and then drying them.

[0021] Preferably, 1% to 2% by weight of foaming maintainer is applied to the artificial soil every 6 to 8 months.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. The method and process provided by this invention are green and environmentally friendly, do not involve heating reaction devices, have mild production conditions and precise process control, and are suitable for industrial production.

[0024] 2. The artificial soil prepared by this method can meet the national soil survey level 2 standard for N, P, and K fertilizer efficiency, and its electrical conductivity meets the requirements for electrical conductivity in soil reclamation.

[0025] 3. In addition, the product of this invention has the properties of water retention, fertilizer retention, heat preservation, loose and porous structure, resistance to leaching, and high germination rate.

[0026] 4. The porous planting layer ecological substrate developed in this invention is based on coal gangue as the main raw material. It not only provides a reliable new approach for the comprehensive utilization of coal gangue, but also improves soil, replaces loess resources, and facilitates ecological restoration. Simultaneously, the porous planting layer ecological substrate possesses many of the functions of soil: it aggregates, retains water and fertilizer through its porous structure, and its organic matter, available phosphorus, total nitrogen, and available potassium levels meet the physical and chemical performance requirements of arable land soil. It can not only replace soil but also act as a soil conditioner to improve soil conditions.

[0027] The mechanism of action of the preparation method of this invention is as follows: alkyl glycosides themselves are surfactants with basic foaming functions, thus they can combine with coal gangue particles on the surface to form foam and achieve a loose granular state. Furthermore, the application of animal and plant protein products can reduce the surface tension of the liquid, thereby forming a stable film on the foam surface, which helps to extend the foam's lifespan, increase soil looseness, and correspondingly improve air permeability. Moreover, the viscosity of polysaccharides helps to enhance the foam structure, making the foam more stable. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 The images show actual photos of existing coal gangue raw materials (left) and porous artificial soil prepared by processing (right).

[0030] Figure 2 yes Figure 1 Enlarged view of the actual product of the present invention.

[0031] Figure 3 This is a photograph of a different plant grown in the porous artificial soil of this invention.

[0032] Figure 4 The experimental crop was pole beans. After sowing leguminous plants, the growth and development of the plants were observed on the first day. The four types of soil used, from left to right, were soil improved from gangue in Huating, Gansu; soil improved from gangue in Shuozhou No. 3 Mine; soil from the flower bed in the courtyard of Xiqu Park, Gujiao; and soil improved from gangue in Xiqu, Gujiao.

[0033] Figure 5 The experimental crop was pole beans. After sowing leguminous plants, the growth and development of the plants were observed on the 6th day. The two types of soil used, from left to right, are soil improved from gangue from Shuozhou No. 3 Mine, soil from the flower bed in the courtyard of Gujiao Xiqu Park, and soil improved from gangue from Gujiao Xiqu.

[0034] Figure 6 The experimental crop was pole beans. After sowing leguminous plants, the growth and development of the plants were observed on the 10th day. The three types of soil used, from left to right, are soil from the flower beds in the courtyard of Gujiao Xiqu Park and soil improved based on Gujiao Xiqu gangue.

[0035] Figure 7 The experimental crop was pole beans. After sowing leguminous plants, the growth and development of the plants were observed one month (30 days). The four types of soil used from left to right were: soil improved from gangue in Huating, Gansu; soil improved from gangue in Shuozhou No. 3 Mine; soil improved from gangue in Xiqu, Gujiao; and soil from the flower beds in the courtyard of Xiqu Park, Gujiao.

[0036] Figure 8 This is a real-life image showing the outdoor growth of a mixture of this porous planting layer ecological substrate and loess from an unnamed ditch.

[0037] Figure 9 It is an existing indicator for classifying the fertility level of cultivated land in a certain type of region.

[0038] Figure 10 This is a photograph of a coal gangue-based porous artificial soil of the present invention applied to a water layer for plant growth.

[0039] Figure 11 This is a photograph of the application of the coal gangue-based porous artificial soil of the present invention in an aquatic layer for plant growth. From a top viewpoint, the water layer is purified and plants have grown on the underwater artificial soil.

[0040] Figure 12 This is a photograph of a coal gangue-based porous artificial soil of the present invention applied to an aquatic layer for fish farming.

[0041] Figure 13This is another set of top-view images showing the application of the coal gangue-based porous artificial soil of the present invention to a water layer.

[0042] Figure 14 This is a diagram of porous artificial soil based on coal gangue that has been soaked in water.

[0043] Figure 15 This is another set of images of porous artificial soil based on coal gangue that has been soaked in water. Figure 14 The amount of foaming agent used is greater than Figure 15 The group. Detailed Implementation

[0044] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0045] This embodiment provides a method for preparing porous artificial soil based on coal gangue, which includes the following steps:

[0046] Step 1: Crush 100 portions of gangue to a size between 13mm and 50mm for later use;

[0047] Step 2: Add 3 parts of slag and 2 parts of fly ash to the gangue obtained in Step 1 and grind it to 130 mesh. Add 1 part of regulator and stir evenly. The regulator is desulfurized gypsum, which has undergone drying pretreatment. The drying pretreatment process of desulfurized gypsum is to dry it at 150℃ for 1 hour before use.

[0048] Step 3: Dilute 3 parts foaming agent and 5 parts foam stabilizer with water and add them to the material in Step 2 and mix well; that is, dilute the foaming agent and foam stabilizer with water 10 times and add them to the material in Step 2 and mix well.

[0049] The foaming agent is selected from alkyl glycosides, soy protein (from animal and plant protein products), and chitosan (a polysaccharide), with animal and plant protein products and polysaccharides each accounting for 10% of the foaming agent. The foam stabilizer is starch.

[0050] Step 4: After drying the well-mixed slurry, we obtain porous artificial soil based on coal gangue.

[0051] The following experiments were conducted on the porous artificial soil based on coal gangue obtained in this embodiment to verify its relevant properties.

[0052] Experiment Example 1: Appearance Observation Experiment.

[0053] The porous structure of the coal gangue artificial soil product of this invention uses coal gangue as the main raw material, and the soil product has the following appearance: Figure 1 right side and Figure 2 As shown. Compared to existing coal gangue materials, the soil obtained by this invention forms a soil-like planting layer ecological substrate with a loose and porous structure, i.e. Figure 1 and Figure 2 It is evident that the coal gangue artificial soil particles are larger, more compactly aggregated, and loose and porous.

[0054] After being processed by this technology, coal gangue has high porosity and adsorption capacity. It can effectively improve soil aeration and water retention, thereby improving soil structure. It has good water absorption and retention properties, does not caking after natural drying, and can be recycled.

[0055] Experiment Example 2: Planting Results Experiment.

[0056] The above-mentioned plants grew well in the coal gangue artificial soil product prepared by this invention. The germination status of different crops is shown in the table below:

[0057] Plant species Survival rate Germination time wheat 100％ 4 days Wheat (soaked and sprouted in advance) 100％ 3 days corn 100％ 4 days Corn (soaked and sprouted in advance) 100％ 2 days Leymus chinensis 90％ 4 days alfalfa 85％ 6 days

[0058] Based on the germination results of various crops, the coal gangue artificial soil product prepared by this invention exhibits better germination performance than ordinary soil. Figure 3 The image shows actual photos of the coal gangue artificial soil product prepared by this invention used for planting various types of plants. For example, plants such as mint, podocarpus, and coriander have grown very good plant morphology, which is better than that of plants grown in ordinary soil.

[0059] Experiment Example 3: Component Detection Experiment.

[0060] The experimental and testing results of coal gangue from Xiqu Mine in Gujiao City;

[0061] Using the washed gangue from Xiqu Mine, after sorting, high-value-added pyrite and low-calorific-value coal are extracted. Then, after processing and foaming according to the preparation method above, a planting layer ecological substrate (based on Xiqu Mine gangue) is prepared. The full composition analysis of the product is shown in the table below.

[0062] Serial Number name Test results Serial Number name Test results 1 <![CDATA[SiO2]]> 62.132 11 <![CDATA[Na2O]]> 0.114 2 <![CDATA[Al2O3]]> 23.880 12 Cl 0.052 3 <![CDATA[Fe2O3]]> 6.239 13 SrO 0.030 4 <![CDATA[SO3]]> 2.565 14 <![CDATA[ZrO2]]> 0.029 5 <![CDATA[K2O]]> 2.189 15 <![CDATA[WO3]]> 0.025 6 CaO 0.897 16 <![CDATA[Rb2O]]> 0.009 7 <![CDATA[TiO2]]> 0.795 17 ZnO 0.008 8 MgO 0.754 18 PbO 0.008 9 <![CDATA[P2O5]]> 0.151 19 <![CDATA[Y2O3]]> 0.005 10 MnO 0.119 20 Total 100.0

[0063] As shown in the table above, the main components of the planting layer ecological substrate (coal gangue-based porous artificial soil) are SiO2, Al2O3, and Fe2O3, accounting for 62.132%, 23.880%, and 6.239% of the total, respectively. Therefore, the planting layer ecological substrate prepared from coal gangue contains the same components as the topsoil, mainly SiO2 and Al2O3, containing humic acid, and also containing about 30 trace elements such as calcium, iron, zinc, sulfur, phosphorus, and potassium. All 15 elements that plants need to obtain from the soil for growth are included in it.

[0064] Experiment Example 4: Salt Content Experiment.

[0065] Soil water-soluble salts are a significant property of saline-alkali soils and a limiting factor for crop growth. This study analyzed the impact of the soluble salt content of the planting layer ecological substrate (coal gangue-based porous artificial soil) on seed germination and crop growth by measuring its concentration. The soluble salt content of the planting layer ecological substrate was determined in the laboratory using both electrical conductivity and gravimetric methods.

[0066] The electrical conductivity (EC) of the porous planting layer ecological substrate (coal gangue-based porous artificial soil) of this invention was determined according to the electrode method for determining soil electrical conductivity (HJ 802-2016). EC25 = 0.23256 ± 2.52 dS / m.

[0067] The water-soluble salt content of the porous planting layer ecological substrate (coal gangue-based porous artificial soil) of the present invention was determined according to "LY / T1251-1999 Analysis of Water-Soluble Salt Content in Forest Soil". The water-soluble salt content was 1.47 g / kg.

[0068] The table below shows the relationship between the electrical conductivity, salinity, and crop growth of saturated soil leachate. This analysis examines the relationship between the salinity of the planting layer's ecological substrate and plant growth.

[0069] Relationship between electrical conductivity of saturated soil leachate and salinity and crop growth:

[0070]

[0071] Based on the above two test results, the ecological substrate (coal gangue-based porous artificial soil) prepared from coal gangue has a low salt content and its salinization level is classified as non-salinized soil. Long-term planting will not cause salinization of the local soil.

[0072] Based on the salinity level given by the soil survey, the salinity of the artificial soil of this invention is extremely low. When mixed with loess, it will not cause changes in the salinity of the loess and can improve the original saline-alkali soil.

[0073] Experimental Example 5: Analysis of Artificial Soil Pollution.

[0074] Heavy metals and organic pollutants were determined according to the "Soil Environmental Quality Standard for Agricultural Land Soil Pollution Risk Control" (GB15618-2018). The test results are shown in the table below:

[0075]

[0076]

[0077] The test results show that the heavy metal and organic pollution monitoring indicators of foamed soil are all lower than the risk screening value standards in the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB 15618-2018); from the perspective of pollution, foamed soil can be used as soil for planting crops.

[0078] Experiment Example 6: Comparison of Effects Experiment.

[0079] In this embodiment, the planting layer ecological substrate, namely a porous artificial soil product based on coal gangue (using gangue from Huating, Gansu; gangue from Shuozhou No. 3 Mine; and gangue from Xiqu Mine as raw materials), was used as the experimental crop: pole bean. After sowing leguminous plants, plant growth and development were observed on days 1, 6, 10, and 30. During the experiment, the porous planting layer ecological substrate was compared with local soil. The experimental results of the porous planting layer ecological substrate (coal gangue-based porous artificial soil) 30 days after sowing are as follows:

[0080] Day 1 shows the growth status of porous artificial soils based on different coal gangue: From left to right, the first two images show the porous planting layer ecological substrates of coal gangue from different provinces (Huating gangue in Gansu and Shuozhou No. 3 Mine gangue, respectively). The two groups of improved soils on the left are pre-planted with plants. The last two images show the planting soil layers of local garden soil and Xiqu coal gangue porous planting layer ecological substrates, planted simultaneously with the same soil layer thickness. As can be seen from the images, since the two groups of improved soils on the left are pre-planted with plants, this coal gangue soil shows good growth and well-developed root systems. This indicates that porous artificial soils formed from coal gangue substrates in different regions are suitable for plant cultivation. The two groups of soils on the right are actual photos from the first day of planting, and no germination has yet occurred.

[0081] On day 6, to compare the germination of plants grown in the porous artificial soil formed from the coal gangue base of this invention and in local garden soil, [the following was observed]. Figure 6 It is evident that the porous planting layer ecological substrate (porous artificial soil formed by coal gangue) predates the local garden soil and has a well-developed root system. The growth status shows that the porous planting layer ecological substrate has excellent growth conditions.

[0082] On the 10th day, the improved soil (coal gangue) in other places (planted earlier) was growing very vigorously, the local garden soil began to sprout and the roots were visible, while the porous planting layer ecological substrate of coal gangue in this project had grown many leaves and was growing well.

[0083] After a long period of time (one month, or 30 days), the local garden soil gradually withered, while the porous planting layer ecological substrate continued to grow vigorously; this demonstrates that the porous artificial soil formed by the coal gangue base of this invention has strong durability and is suitable for long-term planting and use.

[0084] Experiment Example 7: Experiment on compound planting.

[0085] The outdoor growth results of the porous planting layer ecological substrate (porous artificial soil formed from coal gangue) of the present invention, when mixed with ordinary loess, are as follows:

[0086] like Figure 8 As shown, when using porous artificial soil based on coal gangue as the main raw material from Xiqu Mine for on-site planting, the germination rate is nearly 98%, and the germination is fast and the growth is excellent.

[0087] Experimental Example 8: Analysis of Fertilizer Efficacy Testing Results

[0088]

[0089] According to the test results, the relevant indicators of the porous planting layer ecological substrate (porous artificial soil formed by coal gangue) of this invention meet the relevant indicator requirements of the Loess Plateau Loess Type Cultivated Land Type Area Cultivated Land Fertility Grade Classification Indicators in Table 4 of the National Cultivated Land Type Area and Cultivated Land Fertility Grade Classification Standard NY / T 309-1999. Specifically, as follows... Figure 9 The table data shown is as follows.

[0090] In summary, the porous planting layer ecological substrate developed in this invention uses coal gangue as the main raw material, providing a reliable new approach for the comprehensive utilization of coal gangue. It can also improve soil, replace loess resources, and facilitate ecological restoration. Furthermore, the porous planting layer ecological substrate possesses many of the functions of soil, including aggregation, porous water and fertilizer retention, and its organic matter, available phosphorus, total nitrogen, and available potassium content meet the physical and chemical performance requirements of arable land. Therefore, it can not only replace soil but also act as a soil conditioner to improve soil conditions.

[0091] Example 9: Physical Properties and Performance Indicators of Artificial Soil. The soil in the table refers to ordinary garden soil, and the gangue powder is pure gangue powder applied directly without the addition of amendments or other substances. The product refers to the porous artificial soil based on coal gangue prepared according to this invention.

[0092]

[0093] As can be seen from the data in the table above, the water retention rate of the product of the present invention is 37%, the heat preservation performance is 8.1, the loose density is 0.43, and the soil loss rate is 1.27. These data are significantly better than those of existing ordinary soil, which shows that the product of the present invention is very suitable for plant cultivation.

[0094] Experimental Example 10: Performance indicators of soil in the control example. The product refers to the porous artificial soil formed from coal gangue prepared according to this invention. The difference between Control Example 1 and the product is that no animal or plant protein products are used in the foaming agent, while the difference between Control Example 2 and the product is that no polysaccharides are used in the foaming agent.

[0095] As can be seen from the data in the table, the soil properties decreased when animal and plant protein products or polysaccharides were not used. This is mainly because the application of animal and plant protein products can reduce the surface tension of the liquid, while the viscosity of polysaccharides helps to enhance the structure of the foam and make the foam more stable. When these two substances are not used, the performance of the corresponding soil products also decreases.

[0096]

[0097] Example 11:

[0098] In this embodiment, porous artificial soil based on coal gangue is applied underwater and then used for underwater plant cultivation. The porous artificial soil based on coal gangue forms a layered isolation underwater and forms a sponge structure.

[0099] like Figures 10 to 15 As shown, when porous artificial soil based on coal gangue is applied underwater, it forms natural upper and lower layers, and the decomposition is obvious, forming a sponge-like structure. When touched, this artificial soil has a certain elasticity and is immiscible with water. Figure 14 and Figure 15 These are sponge structures taken out after soaking in water for a period of time. It can be seen that they form a whole structure with uniform surface properties and a large number of pores, which can be used to adsorb and purify pollutants in water.

[0100] Figure 14 The artificial soil used in the group had a higher content of foaming maintainer than Figure 15 Different groups, using different amounts of foaming agent, yielded soil structures with varying surface porosity. Figure 14 The pores in the water are significantly larger after soaking. Figure 15 Depending on the environment in which it is used, different types of artificial soil can be selected for different water purification qualities, or suitable artificial soil can be selected by controlling the pore size according to the plant's growth preferences. The control of pore size or density can be achieved by controlling the amount of foaming agent used.

[0101] The sponge-like structure forms a natural, integrated state and will not float, disperse, or dissolve in water, which is significantly different from traditional soil. In addition, the porous artificial soil based on coal gangue obtained in the existing technology will not form this sponge-like structure due to the different binding materials used in its preparation method; it will not form a uniform, integrated structure.

[0102] exist Figures 11 to 13 As shown, after a period of time, the water layer above was purified, indicating that the pores inside the structure of this sponge have an adsorption effect, purifying the upper water layer, and aquatic plants grew on the soil.

[0103] exist Figure 12 As shown, after being applied underwater using porous artificial soil based on coal gangue, the purified water can be used for fish farming.

[0104] Experimental Example 11:

[0105] Foaming maintenance agent is used during the planting process. The foaming maintenance agent is applied directly to the surface of the artificial soil by spraying, or the soil is tilled in the gaps between the plants so that the foaming maintenance agent is mixed into the artificial soil.

[0106] The foaming agent is a composition of alkyl glycosides, animal and plant protein products, and polysaccharides. This composition is obtained by impregnating the alkyl glycosides and animal and plant protein products in a polysaccharide solution and then drying them. After a period of use, soil will inevitably experience changes in its heat retention and loose density due to compaction and other issues. To maintain the soil's inherent properties or slow down this decline, the foaming agent can be applied continuously during planting. This allows for the slow and continuous formation of foam, thus maintaining the soil's inherent properties and resulting in better soil performance.

[0107]

[0108] The preparation method of the foaming maintainer involves dissolving polysaccharides such as chitosan in water or an organic solvent, then immersing alkyl glycosides and solid animal / plant protein products (preferably granular solids) in the chitosan solution and quickly removing them, followed by drying. This forms granules coated with chitosan. When applied to soil, the three substances are combined, facilitating application and allowing for faster synergistic action, avoiding the problems associated with individual application. Furthermore, chitosan itself has a slow-release function; as it gradually degrades, the internal alkyl glycosides and solid animal / plant protein products leak out, gradually forming foam bubbles in the soil, thus maintaining high soil permeability and preserving soil properties. The gradual release of the foaming material from the chitosan membrane extends the application effect. The proportions of the substances in the prepared foaming maintainer are the same as those in the above preparation method.

[0109] Preferably, 1% to 2% by weight of foaming maintainer is applied to the artificial soil every 6 to 8 months.

[0110] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing porous artificial soil based on coal gangue, characterized in that, Includes the following steps: Step 1: Crush 100 portions of gangue to a size between 13mm and 50mm for later use; Step 2: Add 2 to 5 parts of slag and 1 to 3 parts of fly ash to the gangue obtained in Step 1 and grind it to 120 to 140 mesh. Add 0.5 to 2 parts of a regulator and stir evenly. The regulator is desulfurized gypsum, which has undergone drying pretreatment. Step 3: Dilute 2.5 to 6 parts of foaming agent and 3.0 to 8 parts of foam stabilizer with water and add them to the material from Step 2, mixing thoroughly. The foaming agent is selected from alkyl glycosides, animal and plant protein products, and polysaccharides. The weight percentage of animal and plant protein products and polysaccharides in the foaming agent is 10% to 20%, with the remainder being alkyl glycosides. The foam stabilizer is at least one of the following substances: starch, polytetrafluoroethylene, phosphorylated starch, starch xanthate, grafted cellulose, carboxymethylated cellulose, and hydroxypropylated cellulose. The application of animal and plant protein products can reduce the surface tension of the liquid, thereby forming a stable film on the foam surface, which helps to extend the life of the foam, increase soil looseness, and correspondingly improve air permeability. Step 4: After drying the well-mixed slurry, we obtain porous artificial soil based on coal gangue. It also includes the following steps: forming a layered isolation of coal gangue-based porous artificial soil underwater, and forming a sponge structure of coal gangue-based porous artificial soil.

2. The method for preparing coal gangue-based porous artificial soil according to claim 1, characterized in that, Animal and plant protein products are at least one of the following substances: soy protein, silk protein, and gluten protein; The polysaccharide is at least one of the following substances: pectin, alginate, or chitosan.

3. The method for preparing coal gangue-based porous artificial soil according to claim 1, characterized in that, The pretreatment process for desulfurized gypsum involves drying it at 150℃ for 1 hour before use. Dilute the foaming agent and foam stabilizer with water 10 to 25 times and then add them to the material in step 2 and mix well.

4. The method for preparing coal gangue-based porous artificial soil according to claim 1, characterized in that, Slag and fly ash are industrial solid wastes generated from industrial production, with a pH value less than 8.5 and heavy metal content that meets the requirements of GB 15618-2018 for risk control of agricultural land.

5. The method for preparing coal gangue-based porous artificial soil according to claim 1, characterized in that, The raw material for the gangue is either tunneled gangue or washed gangue; In step 4: After drying the well-mixed slurry, it is crushed to obtain coal gangue-based porous artificial soil.

6. A porous artificial soil based on coal gangue, characterized in that, Porous artificial soil based on coal gangue obtained by the preparation method according to any one of claims 1 to 5.

7. The coal gangue-based porous artificial soil according to claim 6, characterized in that, Electrical conductivity EC = 0.23256 ± 2.52 dS / m; water-soluble salt content is 1.47 g / kg; the water retention rate of the coal gangue-based porous artificial soil is 37%, the thermal insulation performance is 8.1℃, and the loose density is 0.43 g / cm³. 3 The soil loss rate was 1.27%.

8. The application of the coal gangue-based porous artificial soil according to claim 6 as a plant cultivation method, characterized in that, Coal gangue-based porous artificial soil is applied underwater and then used for underwater plant cultivation. Foaming maintenance agent is used during the planting process. The foaming maintenance agent is applied directly to the surface of the artificial soil by spraying, or the soil is tilled in the gaps between the plants so that the foaming maintenance agent is mixed into the artificial soil. The foaming maintainer is a composition of alkyl glycosides, animal and plant protein products, and polysaccharides; the composition is obtained by immersing alkyl glycosides and animal and plant protein products in a polysaccharide solution and then drying them. Apply 1% to 2% of the weight of the artificial soil as a foaming maintainer every 6-8 months.

Images