Preparation method of PEG / diatomite composite phase change mining area ecological restoration blanket

Abstract

The invention discloses a preparation method of a PEG / diatomite composite phase change mining area ecological restoration blanket, and belongs to the technical field of ecological restoration materials. The microclimate is regulated and controlled through the phase change material, and the yak hair heat preservation layer, the PLA root system induction layer and the honeycomb structure are combined, so that efficient vegetation recovery and slope stabilization in the low-temperature environment are achieved; the phase change core layer adsorbs PEG by using modified diatomite to realize day and night temperature difference regulation and control; the honeycomb structure enhances the soil fixation capability, and the seed-matrix complex promotes the growth of cold-resistant plants. The restoration blanket overcomes the defects of a traditional technology in a low-temperature and freeze-thaw environment, has the advantages of being accurate in temperature regulation and control, high in freeze-thaw resistance, environmentally friendly and the like, and is suitable for ecological restoration of complex slopes.

Description

Technical Field

[0001] The present invention belongs to the technical field of ecological restoration materials, and specifically relates to a preparation method of a PEG / diatomaceous earth composite phase change ecological restoration blanket suitable for high-altitude and cold mining areas, and especially relates to a design of a composite structure of a composite phase change material and a functional layer. Background Art

[0002] With the intensification of mineral resource development activities in high-altitude mining areas, the emergence of exposed slopes has become an ecological problem that needs to be solved urgently. The exposed slopes formed during the mining process are often prone to soil loss and difficult for plants to establish due to their large slopes, poor soil conditions, and lack of vegetation. Conventional planting methods are usually ineffective on these high and steep slopes because the roots of the plants lack a stable soil environment to support their growth. In addition, these exposed slopes are often exposed to wind and rain erosion, which leads to increased soil erosion and further worsens the conditions for vegetation restoration. Therefore, how to achieve efficient vegetation restoration in such a harsh environment has become the key to restoring the ecosystem in high-altitude mining areas. Concrete spraying uses cement as a binder and mixes organic matter, planting soil, etc. to form a sprayed mixture for slope protection. The technology is difficult, the engineering risk is high, the benefits are short-lived, and the adaptability to high altitudes is average. There are problems with concrete solidification of the ground and difficulty in vegetation growth. The cost is 120-150 yuan / m 2 Netting spraying involves spraying organic soil, fertilizer, and other organic base materials onto the netted slope surface before spraying grass seeds. This technique is difficult and carries high engineering risks. The benefits are long-lasting, but the erosion resistance and greening durability are poor. The cost is 150-200 yuan / m 2 The imported soil spraying method uses the liquid seeding principle to mix and spray. It has simple technology and low engineering risk, but the benefits are short-lived and the adaptability to high altitude is poor. The cost is 80-120 yuan / m 2 As described in "Comparative Study on the Application of Steep Slope Restoration Technologies in Mine Ecological Restoration" ("Environmental Engineering", 2023), different technologies have their own advantages and disadvantages in terms of slope adaptability, environmental risks and costs. It is necessary to find ecological restoration products with low economic costs and good restoration effects according to different situations and terrains.

[0003] Traditional insulation materials, such as straw blankets and ground films, rely on physical isolation and cannot dynamically adjust the surface temperature. For example, although ordinary ground films can provide short-term insulation, they have insufficient oxygen permeability (<200mg / m 2 ·h), hindering CO2 / O2 exchange and inhibiting plant respiration. However, the application of existing phase change materials (PCMs) faces two major bottlenecks: the first is low phase change enthalpy. Conventional paraffin-based PCMs generally have a phase change enthalpy below 150 J / g, making them ineffective in buffering day and night temperature differences. Another drawback is their poor cyclic stability. After 100 thermal cycles, the heat storage efficiency drops by >40%, making them difficult to adapt to the permafrost structure of the plateau.

[0004] The soil in alpine mining areas is primarily sandy, with extremely poor water retention. Freeze-thaw cycles cause soil aggregates to break down, leading to soil erosion rates 30%-50% higher than in more temperate regions. Traditional water-retaining agents, such as sodium polyacrylate, experience a sharp drop in water absorption at low temperatures, reaching well below 30% in extreme cold. They also have poor soil adhesion and are easily lost in runoff. Existing diatomaceous earth-based composite materials, despite their porous structure, have limited water retention. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite phase change ecological restoration blanket with temperature control, water conservation and soil consolidation, and plant induction functions to solve the limitations of ecological restoration caused by low temperature, large temperature difference, and short growing season in high-altitude mining areas.

[0006] The present invention is achieved through the following technical solutions:

[0007] A preparation method for a PEG / diatomite composite phase-change ecological restoration blanket for mining areas, comprising: a PEG nanoporous adsorption phase-change core layer constructed through nano-modification to achieve temperature control and freeze-thaw cycle resistance; a yak hair photothermal insulation layer and a PLA root induction layer integrated through a needle-punching composite and hot-pressing molding process; and a honeycomb three-dimensional structure to achieve three-dimensional anchoring, significantly improving slope adaptability and soil-fixing capacity; and a "seed-microbial matrix filling" integrated into one to achieve biological synergy, ensure basic nutrient conversion function, and maintain a germination rate above 65%. The method specifically comprises the following steps:

[0008] (1) Diatomaceous earth is mixed with a NaOH solution, stirred for reaction, washed with water, and dried to obtain diatomaceous earth with a pore size of 30 to 60 nm; the treated diatomaceous earth is then impregnated with a glycerol aqueous solution.

[0009] (2) Industrial-grade PEG-4000 or PEG-6000 is mixed with diatomaceous earth, and the diatomaceous earth particles are uniformly wrapped with PEG by normal pressure heating and stirring, and a phase change sheet is obtained by hot pressing. The phase change sheet is processed into a honeycomb structure to obtain a phase change layer; PEG is fixed in the pores of the diatomaceous earth in a crystalline state, and the appearance is loose granular and can flow freely.

[0010] (3) A phase change layer is placed on the degradable fiber induction layer, and the seed antifreeze slurry is mixed evenly with the matrix and filled into the honeycomb unit of the phase change layer. The surface is covered with 0.2 to 0.4 cm thick local fine soil, and then covered with a thermal insulation fiber felt layer. The edges of the degradable fiber induction layer, the phase change layer, and the thermal insulation fiber felt layer are fixed (for example, natural rubber latex bonding, edge industrial suture).

[0011] The particle size of the diatomaceous earth in step (1) is ≤150 μm, the mass percentage concentration of the NaOH solution is 5% to 15%; the solid-liquid ratio of the diatomaceous earth to the NaOH solution is 1:3 to 1:7; and the stirring reaction conditions are stirring at 50 to 70° C. for 1 to 3 hours.

[0012] The mass percentage concentration of the glycerol aqueous solution in step (1) is 3% to 7%, the solid-liquid ratio of the treated diatomaceous earth to the glycerol aqueous solution is 1:2 to 1:4, and the impregnation process is stirred at 15 to 30° C. for 0.5 to 1.5 hours.

[0013] In step (2), the mass ratio of industrial-grade PEG-4000 to diatomaceous earth is 1:1 to 1:2, and the heating and stirring method is: stirring at 80° C. for 2 h.

[0014] The hot pressing molding parameters in step (2) are: temperature 65℃~90℃, pressure 5~9MPa, phase change sheet thickness 0.7~1mm, 1~2mm hot melt zone reserved on the edge for interlayer bonding, and the honeycomb unit side length of the honeycomb structure is set to 4~6cm.

[0015] The preparation process of the seed antifreeze paste in step (3) is as follows: bluegrass, dwarf ...

[0016] The preparation process of the matrix in step (3) is as follows: diatomaceous earth: 30% to 50%, peat soil: 25% to 35%, tailings sand: 15% to 25%, yak dung: 5% to 15% are mixed in volume ratio to obtain a mixture A, and 2% to 4% by mass of a slow-release nitrogen fertilizer and 1×10 6 ~1×10 8 CFU / kg, and then adjust the moisture content to 30% to 35% to obtain the matrix.

[0017] The thermal insulation fiber felt layer is preferably made of local yak hair coarse felt with a gram weight of 180-300g / ㎡, and the surface is coated with a graphite powder-acrylic emulsion coating with a mass percentage concentration of 8%-15% and a coating thickness of 0.1-0.3mm. Various materials such as yak hair, camel hair, and basalt fiber are allowed to be used.

[0018] The degradable fiber induction layer is preferably made of industrial general-purpose PLA fiber felt with a gram weight of 100g / ㎡, with holes drilled at the bottom, with a hole diameter of 0.3-0.6mm and a hole density of 15-25 holes / cm 2 , allowing snowmelt and rainwater to penetrate, increasing soil moisture content by 22%, and guiding the root system to achieve "directional deep rooting".

[0019] The present invention cooperates with the phase change layer, diatomaceous earth load, honeycomb unit, upper and lower covering layers to obtain a stable composite phase change material, which absorbs heat for cooling, releases heat for insulation, and can also avoid liquid leakage. At the same time, it provides a porous skeleton to enhance air permeability, prevent material failure caused by water accumulation in the phase change layer, and provide suitable humidity for plants to induce root growth; honeycomb rigid support is formed by molding at room temperature, which confines the phase change material in independent units to prevent overall displacement; and the actual service life can be extended to 8-12 years.

[0020] The beneficial effects of the present invention are:

[0021] (1) The phase change core layer uses a PEG-diatomaceous earth composite system to absorb and store heat during the day and release and keep warm at night, controlling the temperature difference between day and night in the blanket to within 15°C. The effective growth period is increased by 20-30 days compared with the bare slope, the seed germination temperature threshold is reduced to 0°C, and the germination rate can reach more than 60%.

[0022] (2) The nanopores of diatomaceous earth are expanded by NaOH and modified with propylene glycol, making the low-temperature distribution of PEG more stable, without leakage during freeze-thaw cycles, and the anti-freeze-thaw ability is improved by 50% compared with traditional materials, ensuring the survival rate of seedlings over the winter at 65%.

[0023] (3) The honeycomb-shaped three-dimensional grid provides mechanical support and strong wind resistance. Combined with edge anchoring, the anti-slip force is increased by 40% compared with the flat blanket, effectively resisting high-altitude strong winds and rain erosion, and reducing runoff erosion by more than 50%.

[0024] (4) The root induction layer PLA fiber felt and naphthaleneacetic acid coating guide the roots of deep-rooted plants to grow directional along the mesh holes. Three months after repair, the average root depth reaches 15 cm, forming a dual soil reinforcement system of "material anchoring + root reinforcement".

[0025] (5) The upper layer of yak wool felt and the lower layer of PLA fiber felt are degradable, replacing traditional non-degradable materials and reducing white pollution; the phase change core layer has a lifespan of 5-8 years, achieving "short-term support-long-term ecological transition".

[0026] (6) Cow and sheep manure and Bacillus subtilis promote the decomposition of organic matter and nutrient recycling. Within 3 months, the total nitrogen content in the rhizosphere soil increased by 20%, the number of microorganisms increased by 3 times, and the fertility of poor mineral soil was improved simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the composite phase change blanket structure.

[0028] 1-Upper layer: thermal insulation fiber felt (yak hair felt); 2-Photo layer: honeycomb; 3-Lower layer: degradable fiber induction layer (PLA fiber felt). DETAILED DESCRIPTION

[0029] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0030] Example 1

[0031] A method for preparing a PEG / diatomite composite phase change ecological restoration blanket suitable for high-altitude mining areas comprises the following steps:

[0032] (1) Screening diatomaceous earth with a local particle size of less than 100 μm and mixing it with 10% NaOH solution in a ratio of 1:5, stirring at 60°C for 2 hours, washing with water and drying to obtain diatomaceous earth with a pore size of 30 to 60 nm, and then impregnating the treated diatomaceous earth with a glycerol aqueous solution, wherein the mass percentage concentration of the glycerol aqueous solution is 3%, and the solid-liquid ratio of the treated diatomaceous earth to the glycerol aqueous solution is 1:2. The impregnation process is stirring at 15°C for 0.5 hours, draining and setting aside.

[0033] (2) Industrial-grade PEG-4000 and diatomaceous earth were mixed in a mass ratio of 1:1, and stirred at 80°C for 2 h to allow the PEG to evenly wrap the diatomaceous earth particles. Under the conditions of temperature of 65°C and pressure of 5 MPa, a phase change sheet with a thickness of 0.7 mm was obtained by hot pressing. The phase change sheet was processed into a honeycomb structure (the side length of the honeycomb unit was set to 4 cm) to obtain a phase change layer.

[0034] (3) Place the phase change layer on the degradable fiber induction layer, mix the seed antifreeze slurry with the matrix evenly and fill it into the honeycomb unit of the phase change layer, cover the surface with 0.2 cm thick local fine soil, and then cover it with the thermal insulation fiber felt layer. Fix the edges of the degradable fiber induction layer, phase change layer, and thermal insulation fiber felt layer.

[0035] The preparation process of the seed antifreeze paste is as follows: bluegrass, dwarf ...

[0036] The preparation process of the matrix is ​​as follows: diatomaceous earth: 30%, peat soil: 35%, tailings sand: 25%, yak dung: 10% are mixed in a volume ratio to obtain a mixture A, and 2% by mass of a slow-release nitrogen fertilizer and 1×10 cold-resistant Bacillus subtilis inoculant are added to the mixture A. 6 ~1×10 8 CFU / kg, and then the moisture content was adjusted to 30% to obtain the matrix.

[0037] (4) The seeds and substrate were mixed manually at a ratio of 1:12 and directly filled into the honeycomb unit to 90% of the volume. The surface was covered with 0.2 cm of local fine soil, and finally the composite blanket was anchored at a distance of 20 cm.

[0038] The degradable fiber induction layer described in this embodiment is preferably a local yak hair woolen felt with a gram weight of 180g / ㎡, and the surface is coated with a graphite powder-acrylic emulsion coating with a mass percentage concentration of 8% and a coating thickness of 0.1mm. Various materials such as yak hair, camel hair, and basalt fiber are allowed to be used.

[0039] The thermal insulation fiber felt layer of this embodiment is preferably an industrial general-purpose PLA fiber felt with a gram weight of 100 g / ㎡, and the bottom is drilled with holes with a diameter of 0.3 mm and a hole density of 15 holes / cm 2 , allowing snowmelt and rainwater to penetrate, increasing soil moisture content by 22%, and guiding the root system to achieve "directional deep rooting".

[0040] (5) The upper layer of the composite blanket is made of yak wool felt and the phase change sheet bonded together by natural rubber latex, and the lower layer of the composite blanket is made of PLA fiber felt with a gram weight of 100g / ㎡, and the edges are sewn with cotton thread.

[0041] (6) The repair blanket is connected to the protective net through edge clips and reinforced with 4 U-shaped anchor nails with a diameter of 8mm per square meter. Water is sprayed every day in the first week after construction, and twice a week from the second week onwards.

[0042] The PEG / diatomaceous earth composite phase change mining ecological restoration blanket was laid in the mining slag dump for restoration. The germination rate was 65%, the root system depth reached 12 cm in 3 months, forming a network soil-solidifying structure, and the vegetation coverage rate reached 60% in 3 months. The phase change layer maintained the day and night temperature difference in the blanket at <15°C, which increased the effective growth period by 18 days compared with the bare slag dump. After 30 freeze-thaw cycles of -5°C to 10°C, the blanket did not crack.

[0043] Example 2

[0044] A method for preparing a PEG / diatomite composite phase change ecological restoration blanket suitable for high-altitude mining areas comprises the following steps:

[0045] (1) Screening diatomaceous earth with a local particle size of less than 100 μm and mixing it with 10% NaOH solution in a ratio of 1:5, stirring at 60° C. for 2 h, washing with water and drying to obtain diatomaceous earth with a pore size of 30 to 60 nm, and then impregnating the treated diatomaceous earth with a glycerol aqueous solution, wherein the mass percentage concentration of the glycerol aqueous solution is 5%, and the solid-liquid ratio of the treated diatomaceous earth to the glycerol aqueous solution is 1:3. The impregnation process is stirring at 25° C. for 1 hour, draining and setting aside.

[0046] (2) Industrial-grade PEG-4000 and diatomaceous earth were mixed in a mass ratio of 1:1.5, and stirred at 80°C for 2 h to allow the PEG to evenly wrap the diatomaceous earth particles. Under the conditions of temperature of 78°C and pressure of 7 MPa, a phase change sheet with a thickness of 0.8 mm was obtained by hot pressing. The phase change sheet was processed into a honeycomb structure (the side length of the honeycomb unit was set to 5 cm) to obtain a phase change layer.

[0047] (3) Place the phase change layer on the degradable fiber induction layer, mix the seed antifreeze slurry with the matrix evenly and fill it into the honeycomb unit of the phase change layer. Cover the surface with 0.3 cm thick local fine soil, and then cover it with the thermal insulation fiber felt layer. Fix the edges of the degradable fiber induction layer, phase change layer, and thermal insulation fiber felt layer.

[0048] The preparation process of the seed antifreeze paste is as follows: bluegrass, dwarf ...

[0049] The preparation process of the matrix is ​​as follows: diatomaceous earth: 40%, peat soil: 30%, tailings sand: 15%, yak dung: 15% are mixed in a volume ratio to obtain a mixture A, and 3% by mass of a slow-release nitrogen fertilizer and 1×10 cold-resistant Bacillus subtilis inoculant are added to the mixture A. 6 ~1×10 8 CFU / kg, and then the moisture content was adjusted to 32% to obtain the matrix.

[0050] (4) The seeds and substrate were mixed manually at a ratio of 1:12 and directly filled into the honeycomb unit to 90% of the volume. The surface was covered with 0.2 cm of local fine soil, and finally the composite blanket was anchored at a distance of 20 cm.

[0051] The degradable fiber induction layer described in this embodiment is preferably a local yak hair woolen felt with a gram weight of 240g / ㎡, and the surface is coated with a graphite powder-acrylic emulsion coating with a mass percentage concentration of 12% and a coating thickness of 0.2mm. Various materials such as yak hair, camel hair, and basalt fiber are allowed to be used.

[0052] The thermal insulation fiber felt layer in this embodiment is preferably an industrial general-purpose PLA fiber mesh with a gram weight of 110g / ㎡, and the bottom is drilled with holes with a diameter of 0.4mm and a hole density of 20 holes / cm 2 , allowing snowmelt and rainwater to penetrate, increasing soil moisture content by 25%, and guiding the root system to achieve "directional deep rooting".

[0053] (5) The upper layer of the composite blanket is made of yak wool felt and the phase change sheet bonded together by natural rubber latex. The lower layer of the composite blanket is made of PLA fiber felt with a gram weight of 110g / ㎡, and the edges are sewn with cotton thread.

[0054] (6) The repair blanket is connected to the protective net through edge clips and reinforced with 4 U-shaped anchor nails with a diameter of 8mm per square meter. Water is sprayed every day in the first week after construction, and twice a week from the second week onwards.

[0055] The PEG / diatomaceous earth composite phase change mining ecological restoration blanket was laid in the mining slag dump for restoration. The germination rate was 70%, the root system depth reached 15 cm in 3 months, forming a network soil-solidifying structure, and the vegetation coverage rate reached 72% in 3 months. The phase change layer maintained the day and night temperature difference in the blanket at <15°C, which increased the effective growth period by 22 days compared with the bare slag dump. After 40 freeze-thaw cycles of -5°C to 10°C, the blanket did not crack.

[0056] Example 3

[0057] A method for preparing a PEG / diatomite composite phase change ecological restoration blanket suitable for high-altitude mining areas comprises the following steps:

[0058] (1) Screening diatomaceous earth with a local particle size of less than 100 μm and mixing it with 10% NaOH solution in a ratio of 1:5, stirring at 60° C. for 2 h, washing with water and drying to obtain diatomaceous earth with a pore size of 30 to 60 nm, and then impregnating the treated diatomaceous earth with a glycerol aqueous solution, wherein the mass percentage concentration of the glycerol aqueous solution is 7%, and the solid-liquid ratio of the treated diatomaceous earth to the glycerol aqueous solution is 1:4. The impregnation process is stirring at 30° C. for 1.5 hours, draining and setting aside.

[0059] (2) Industrial-grade PEG-4000 and diatomaceous earth were mixed in a mass ratio of 1:2, and stirred at 80°C for 2 h to allow the PEG to evenly wrap the diatomaceous earth particles. Under the conditions of temperature of 90°C and pressure of 9 MPa, a phase change sheet with a thickness of 1 mm was obtained by hot pressing. The phase change sheet was processed into a honeycomb structure (the side length of the honeycomb unit was set to 6 cm) to obtain a phase change layer.

[0060] (3) Place the phase change layer on the degradable fiber induction layer, mix the seed antifreeze slurry with the matrix evenly and fill it into the honeycomb unit of the phase change layer. Cover the surface with 0.4 cm thick local fine soil, and then cover it with the thermal insulation fiber felt layer. Fix the edges of the degradable fiber induction layer, phase change layer, and thermal insulation fiber felt layer.

[0061] The preparation process of the seed antifreeze paste is as follows: bluegrass, dwarf ...

[0062] The preparation process of the matrix is ​​as follows: diatomaceous earth: 50%, peat soil: 25%, tailings sand: 20%, yak dung: 5% are mixed in a volume ratio to obtain a mixture A, and 2% by mass of a slow-release nitrogen fertilizer and 1×10 cold-resistant Bacillus subtilis inoculant are added to the mixture A. 6 ~1×10 8 CFU / kg, and then the moisture content was adjusted to 35% to obtain the matrix.

[0063] (4) The seeds and substrate were mixed manually at a ratio of 1:12 and directly filled into the honeycomb unit to 90% of the volume. The surface was covered with 0.2 cm of local fine soil, and finally the composite blanket was anchored at a distance of 20 cm.

[0064] The degradable fiber induction layer described in this embodiment is preferably a local yak hair woolen felt with a gram weight of 300g / ㎡, and the surface is coated with a graphite powder-acrylic emulsion coating with a mass percentage concentration of 15% and a coating thickness of 0.3mm. Various materials such as yak hair, camel hair, and basalt fiber are allowed to be used.

[0065] The thermal insulation fiber felt layer in this embodiment is preferably an industrial general-purpose PLA fiber mesh with a gram weight of 120g / ㎡, and the bottom is drilled with holes with a diameter of 0.6mm and a hole density of 25 holes / cm 2 , allowing snowmelt and rainwater to penetrate, increasing soil moisture content by 30%, and guiding the root system to achieve "directional deep rooting".

[0066] (5) The upper layer of the composite blanket is made of yak wool felt and the phase change sheet bonded together by natural rubber latex. The lower layer of the composite blanket is made of a PLA fiber mesh with a gram weight of 120 g / ㎡, and the edges are sewn with cotton thread.

[0067] (6) The repair blanket is connected to the protective net through edge clips and reinforced with 4 U-shaped anchor nails with a diameter of 8mm per square meter. Water is sprayed every day in the first week after construction, and twice a week from the second week onwards.

[0068] The PEG / diatomaceous earth composite phase change mining ecological restoration blanket was laid in the mining slag dump for restoration. The germination rate was 75%, the root system depth reached 18 cm in 3 months, forming a network soil-solidifying structure, and the vegetation coverage rate reached 75% in 3 months. The phase change layer maintained the day and night temperature difference in the blanket at <15°C, which increased the effective growth period by 25 days compared with the bare slag dump. After 60 freeze-thaw cycles of -5°C to 10°C, the blanket did not crack.

[0069] Various embodiments of the present invention have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The choice of terms used in the present invention is intended to best explain the principles, practical applications, or improvements to technologies in the market of the various embodiments, or to enable other persons skilled in the art to understand the various embodiments disclosed in the present invention.

Claims

1. A method for preparing a PEG / diatomite composite phase change mining area ecological restoration blanket, characterized in that: The specific steps include: (1) diatomaceous earth is mixed with a NaOH solution, stirred for reaction, washed with water, and dried to obtain diatomaceous earth with a pore size of 30 to 60 nm; the treated diatomaceous earth is then impregnated with a glycerol aqueous solution; (2) industrial-grade PEG-4000 was mixed with diatomaceous earth, and the diatomaceous earth particles were uniformly coated with PEG by a normal pressure heating and stirring method, and a phase change sheet was obtained by hot pressing, and the phase change sheet was processed into a honeycomb structure to obtain a phase change layer; (3) Place a phase change layer on the degradable fiber induction layer, mix the seed antifreeze slurry with the matrix evenly and fill it into the honeycomb unit of the phase change layer. Cover the surface with 0.2 to 0.4 cm thick local fine soil, and then cover it with a thermal insulation fiber felt layer. Fix the edges of the degradable fiber induction layer, phase change layer, and thermal insulation fiber felt layer.

2. The method for preparing the PEG / diatomite composite phase change mining area ecological restoration blanket according to claim 1, characterized in that: The particle size of the diatomaceous earth in step (1) is ≤150 μm, the mass percentage concentration of the NaOH solution is 5% to 15%; the solid-liquid ratio of the diatomaceous earth to the NaOH solution is 1:3 to 1:7; and the stirring reaction conditions are stirring at 50 to 70° C. for 1 to 3 hours.

3. The method for preparing the PEG / diatomite composite phase change mining area ecological restoration blanket according to claim 1, characterized in that: The mass percentage concentration of the glycerol aqueous solution in step (1) is 3% to 7%, the solid-liquid ratio of the treated diatomaceous earth to the glycerol aqueous solution is 1:2 to 1:4, and the impregnation process is stirred at 15 to 30° C. for 0.5 to 1.5 hours.

4. The method for preparing the PEG / diatomite composite phase change mining area ecological restoration blanket according to claim 1, characterized in that: In step (2), the mass ratio of industrial-grade PEG-4000 to diatomaceous earth is 1:1 to 1:2, and the heating and stirring method is: stirring at 80° C. for 2 h.

5. The method for preparing the PEG / diatomite composite phase change mining area ecological restoration blanket according to claim 1, characterized in that: The hot pressing molding parameters in step (2) are: temperature 65℃~90℃, pressure 5~9MPa, thickness of the phase change sheet 0.7~1mm, and a 1~2mm hot melt zone reserved at the edge for interlayer bonding.

6. The method for preparing the PEG / diatomite composite phase change mining area ecological restoration blanket according to claim 1, characterized in that: The preparation process of the seed antifreeze paste in step (3) is as follows: bluegrass, dwarf ...

7. The method for preparing the PEG / diatomite composite phase change mining area ecological restoration blanket according to claim 1, characterized in that: The preparation process of the matrix in step (3) is as follows: diatomaceous earth: 30% to 50%, peat soil: 25% to 35%, tailings sand: 15% to 25%, yak dung: 5% to 15% are mixed in volume ratio to obtain a mixture A, and 2% to 4% by mass of a slow-release nitrogen fertilizer and 1×10 6 ~1×10 8 CFU / kg, and then adjust the moisture content to 30% to 35% to obtain the matrix.

8. The method for preparing the PEG / diatomite composite phase change mining area ecological restoration blanket according to claim 1, characterized in that: The degradable fiber induction layer is preferably made of industrial general-purpose PLA fiber felt with a gram weight of 100g / ㎡, with holes drilled at the bottom, with a hole diameter of 0.3-0.6mm and a hole density of 15-25 holes / cm 2 .

9. The method for preparing the PEG / diatomite composite phase change mining area ecological restoration blanket according to claim 1, characterized in that: The thermal insulation fiber felt layer is preferably a local yak hair roving felt with a gram weight of 180 to 300 g / m2, and the surface is coated with a graphite powder-acrylic acid emulsion coating with a mass percentage concentration of 8% to 15% and a coating thickness of 0.1 to 0.3 mm.

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