A three-dimensional coupled water retention and moisture conservation method for coal mine spoil heaps in sandy wasteland

Abstract

This invention discloses a three-dimensional coupled water retention and moisture conservation method for coal mine spoil heaps in sandy wastelands. It utilizes the characteristic of superoxide dehydrogenase, an activating substance produced by an activator, to rapidly stimulate the release of organic nutrients, thereby improving the structure of newly formed soil in sandy coal mine spoil heaps and solving the problem of low efficiency in improving water retention and moisture conservation capacity. Through vegetation configuration, a vegetation-soil synergistic remediation system of "activator improvement - sand-resistant herbaceous cover - root system integration" is formed, addressing the lack of sustainability in the improvement of the ecosystem of newly formed soil in sandy coal mine spoil heaps. Furthermore, through a constant-temperature and constant-pressure high-order acidification reaction with wood vinegar, the heavy metal elements in earthworm castings and peat in the materials are delayed, solving the problem of heavy metal ion pollution in the materials and eliminating ecological risks.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration of mining areas, especially the restoration of special landforms such as coal mine spoil heaps in sandy wastelands, and specifically to a three-dimensional coupled water retention and moisture conservation method for coal mine spoil heaps in sandy wastelands. Background Technology

[0002] In recent years, the remediation technology of coal mine spoil heaps in sandy wastelands has received widespread attention and yielded fruitful research results. Currently, the main remediation technologies are divided into three categories: one is to improve the soil water retention capacity of coal mine spoil heaps in sandy wastelands through special configurations of psammophytic plants, such as the mixed sowing of black locust + Chinese pine + Caragana korshinskii (1:2:1), which increases the survival rate and coverage of vegetation. However, due to nutrient deficiency, vegetation growth is sluggish, reducing the efficiency of improving the water retention capacity of coal mine spoil heaps. Secondly, engineering measures are used to restore coal mine spoil heaps in sandy wastelands. For example, land-saving and time-saving mining methods such as "land-saving and loss-reducing slope control technology," "stripping-mining-dumping-covering collaborative operation method," and "inner dumping method with inclined base" are used to reduce groundwater damage caused by open-pit mining, thereby increasing soil moisture content. Ecological blankets made from composite materials, combining fiber and coconut fiber (1.5:1), have increased surface soil nutrients and improved surface soil moisture content and enzyme activity in sandy coal mine spoil heaps. However, the raw materials contain heavy metal ions, posing an ecological risk. Physical modification methods, such as using imported soil (yellow cotton soil), are also employed to improve soil water and fertilizer retention capacity in sandy coal mine spoil heaps. Thirdly, biotechnology is used to improve site conditions in sandy coal mine spoil heaps by utilizing the rhizobia found in legumes. Inoculation with extracted rhizobia can enhance plant resistance, improve site conditions, and enhance the moisture retention capacity of sandy coal mine spoil heaps. Ecological restoration of mining areas, especially the restoration of special landforms such as coal mine spoil heaps in sandy wastelands, is a major issue that urgently needs to be addressed to achieve high-quality development in my country's energy regions.

[0003] The existing disadvantages of the above technologies include: (1) In the short term, due to the poor soil nutrients in the original landform, the vegetation restoration effect is slow and lagging, which affects the efficiency of improving the water retention capacity of the newly constructed soil in the coal mine spoil heap in sandy wasteland; (2) Engineering measures can improve the water retention capacity of the newly constructed soil in the coal mine spoil heap in sandy wasteland to a certain extent, but considering the high cost and the pollution of heavy metal ions, it is not possible to promote it on a large scale and in an ecological manner; (3) Through biotechnology, some fungi or microorganisms can be used to improve the physicochemical properties of the newly constructed soil in the coal mine spoil heap in sandy wasteland from the microstructure, thereby improving the water retention capacity of the newly constructed soil in the spoil heap. However, fungi or microorganisms are easily affected by environmental factors and lack the sustainability of systematic improvement of the newly constructed soil in the coal mine spoil heap in sandy wasteland.

[0004] The technical problems to be solved by this application include: (1) improving the structure of newly constructed soil in sandy wasteland coal mine spoil heaps by rapidly stimulating the release of organic nutrients through the activating substance superoxide dehydrogenase generated by the activator, thus solving the problem of low efficiency in improving water retention capacity; (2) forming a vegetation-soil synergistic restoration system of "activator improvement - sand-resistant herbaceous covering - root system integration" through vegetation configuration, thus solving the problem of lack of sustainability in the improvement of the ecosystem of newly constructed soil in sandy wasteland coal mine spoil heaps; (3) delaying the heavy metal elements (Ni, Cu, Zn and Cr) in earthworm castings and peat in the material through the constant temperature and pressure high-order acidification reaction of wood vinegar, thus solving the problem of heavy metal ion pollution in the material and eliminating ecological risks. Summary of the Invention

[0005] A three-dimensional coupled water retention and moisture conservation method for coal mine spoil heaps in sandy wastelands, the method comprising:

[0006] Step S1: Mix straw and peat in a ratio of (25%-35%):(65%-75%) and mix for 10-20 minutes using a mixer;

[0007] Step S2: Mix the mixture obtained in step S1 with earthworm castings at a ratio of (60%-70%):(30%-40%) and mix for 10-20 minutes using a mixer.

[0008] Step S3: Grind the mixture obtained in step S2 for 25-35 minutes, and then screen out materials with a particle size of 0.30mm-0.40mm.

[0009] Step S4: The mixture obtained in step S3 is subjected to high-level acidification treatment at a constant temperature of 79℃-82℃ and a constant pressure of 1.58MPa-1.62MPa in a spherical reactor with a radius of 5m-7m for 390-410 minutes. The acidification reaction reagent is wood vinegar, and the reaction reagent is added at a ratio of 10%-12%.

[0010] Step S5: The product obtained in step S4 is pressed into spherical structures with a diameter of 7mm-9mm using a granulator. The final product is a new soil activator.

[0011] Step S6: Drill holes on the surface of the open-pit coal mine spoil heap in the sandy wasteland. The holes should be 7cm-9cm in diameter and 6cm-8cm deep, forming an angle of 40°-50° with the ground. Drill up to 60 holes per meter. 2 -100 pieces / m 2 After determining the density, the product obtained in step S5 is then filled into the pores.

[0012] Step S7: Use a novel sand-resistant plant, *Leymus chinensis* and *Apocynum venetum*, in a ratio of 2:1 to 3:2, and sow them in the holes of Step S6 by hole sowing. The sowing dosage of mixed seeds is 30-35 seeds per hole; forming a vegetation-soil synergistic remediation system of "activator improvement - sand-resistant herb cover - root integration".

[0013] When the peat and straw are mixed in a ratio of (25%-35%):(65%-75%), the straw will quickly disperse when it comes into contact with water, and the activator can quickly combine with the coal mine spoil heap in the sandy wasteland, which can stimulate the metabolism of microorganisms to produce activating substances such as superoxide dehydrogenase.

[0014] The vegetation-soil synergistic remediation technology system of "activator improvement - sand-resistant herbaceous cover - root system integration" has the ability to continuously remediate coal mine spoil heaps in sandy wastelands.

[0015] The wood vinegar solution has a retardation effect on heavy metal ions in peat and earthworm castings under a constant temperature of 79℃-82℃ and a constant pressure of 1.58MPa-1.62MPa. It transforms the free state that can be absorbed by plants into a fixed state that cannot be absorbed, reduces the activity of chromium, copper, and zinc, and removes the ecological risks of soil activators.

[0016] The advantages and effects of this application are as follows:

[0017] (1) Promotes rapid increase in moisture content of open-pit coal mine spoil heaps in sandy wastelands: This invention contains straw, which disperses rapidly upon contact with water, and the activator can quickly combine with the spoil heaps in sandy wastelands, such as... Figure 1 As shown, after applying the activator to the spoil heap in July, the soil moisture content increased significantly within one month, from 6.95% to 9.83%, an increase of 41.44%, achieving a rapid improvement in water retention capacity. Secondly, the superoxide dehydrogenase produced by straw and peat moss can promote the release of organic nutrients from earthworm castings, promote the formation of soil aggregates in the spoil heap, enhance soil interfacial strength, and reduce water evaporation, thus comprehensively improving the water retention capacity of the soil in sandy coal mine spoil heaps from multiple physical and chemical dimensions. Compared with July, the increase in soil moisture content in spoil heaps after applying the activator in August, September, and October ranged from 41.44% to 88.49%.

[0018] (2) Promoting the sustainability of vegetation systems in coal mine spoil heaps in sandy wastelands: Through long-term research, it has been found that when *Leymus chinensis* and *Apocynum venetum* are planted in a specific ratio, their root systems achieve a three-dimensional interweaving, forming a vegetation-soil synergistic remediation system of "activator improvement + sand-resistant herbaceous cover + root fusion" in combination with activators. This continuously improves the soil porosity of the spoil heap, thereby sustainably enhancing the water retention capacity of coal mine spoil heaps in sandy wastelands and improving the soil's water retention properties. Figure 2 As shown, after planting in 2021, no human intervention was carried out in 2021, 2022, and 2023, and the plant biomass still increased significantly, by 99.59%, 191.30%, and 271.58% respectively compared with the original landform in 2021, achieving a long-term and stable restoration effect.

[0019] (3) High-level acidification reaction of wood vinegar at constant temperature and pressure delays the release of heavy metal ions in the soil activator: After high-level acidification reaction of wood vinegar at constant temperature and pressure, the heavy metal ions in the soil activator can be delayed, converting the free state that can be absorbed by plants into the fixed state that cannot be absorbed, reducing the activity of chromium, copper, zinc, etc., and removing the ecological risks of the soil activator. Figure 3 As shown, after the isothermal high-order acidification reaction, the heavy metal contents of Ni, Cu, Zn and Cr in the activator decreased by 62.5%, 67.84%, 81.75% and 83.33%, respectively.

[0020] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0021] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0023] in:

[0024] Figure 1 Soil moisture content of spoil heaps at different times;

[0025] Figure 2 Plant biomass in spoil heaps at different times;

[0026] Figure 3 Changes in heavy metal ions after isothermal high-order acidification treatment. Specific Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0028] It should be understood that the phrase "an embodiment" or "this embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "an embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0029] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0030] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.

[0031] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0032] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.

[0033] Example 1

[0034] This embodiment provides an overall process for a three-dimensional coupled water retention and moisture conservation method for coal mine spoil heaps in sandy wastelands.

[0035] Step S1: Mix straw (30% ± 0.1%) and peat (70% ± 0.1%) together using a mixer for 15 minutes;

[0036] Step S2: Combine the mixture obtained in step S1 with earthworm castings at a ratio of (65%:35%) and mix for 15 minutes using a mixer.

[0037] Step S3: Grind the mixture obtained in step S2 for 30 minutes and then screen out the material with a particle size of 0.35±0.01mm;

[0038] Step S4: The mixture obtained in step S3 is subjected to high-level acidification treatment under constant temperature and pressure in a spherical reactor with a radius of 5m. The acidification treatment time is 400±5 minutes, the constant temperature is 80℃±0.5℃, the constant pressure is 1.60±0.05MPa, and the acidification reaction reagent is wood vinegar (pH 3.5±0.01), with an addition ratio of 10%±0.05% (to delay Ni, Cu, Zn and Cr heavy metal ions).

[0039] Step S5: The product obtained in step S4 is pressed into spherical structures with a diameter of 7mm ± 0.05mm using a granulator. The final product is a new soil activator.

[0040] Step S6: Drill holes on the surface of the open-pit coal mine spoil heap in the sandy wasteland. The holes should form a 45° angle with the ground, with a diameter of 9cm ± 0.5cm and a depth of 6cm ± 0.05cm. The drilling density should be 80 ± 2 holes / m². 2 Then fill the holes with the product obtained in step S5.

[0041] Step S7: A novel sand-resistant plant mixture of *Leymus chinensis* and *Apocynum venetum* in a 2:1 ratio is used. The mixture is sown in the holes from Step S6 using a hole-sowing method, with a seed density of 35 seeds per hole. After sowing, the mixture is covered with undisturbed soil and leveled. This forms a vegetation-soil synergistic remediation system of "activator improvement - sand-resistant herbaceous cover - root integration," significantly improving the water retention capacity of open-pit coal mine spoil heaps in sandy wastelands.

[0042] Example 2

[0043] This embodiment provides an overall process for a three-dimensional coupled water retention and moisture conservation method for coal mine spoil heaps in sandy wastelands.

[0044] Step S1: Mix straw (25% ± 0.1%) and peat (75% ± 0.1%) together using a mixer for 10 minutes;

[0045] Step S2: Mix the mixture obtained in step S1 with earthworm castings at a ratio of 60%:40% and mix for 10 minutes using a mixer;

[0046] Step S3: Grind the mixture obtained in step S2 for 25 minutes and then screen out the material with a particle size of 0.30±0.01mm;

[0047] Step S4: The mixture obtained in step S3 is subjected to high-level acidification treatment under constant temperature and pressure in a spherical reactor with a radius of 6m. The acidification treatment time is 390±5 minutes, the constant temperature is 81℃±0.5℃, the constant pressure is 1.58±0.05MPa, and the acidification reaction reagent is wood vinegar (pH 3.4±0.01) with an addition ratio of 11%±0.05%.

[0048] Step S5: The product obtained in step S4 is pressed into spherical structures with a diameter of 8mm ± 0.05mm using a granulator. The final product is a new soil activator.

[0049] Step S6: Drill holes on the surface of the open-pit coal mine spoil heap in the sandy wasteland. The holes should form a 40° angle with the ground, with a diameter of 8cm ± 0.5cm and a depth of 7cm ± 0.05cm. The drilling density should be 90 ± 2 holes / m². 2 Then fill the holes with the product obtained in step S5.

[0050] Step S7: Mix the new sand-resistant plants, Leymus chinensis and Apocynum venetum, in a 3:2 ratio and sow them in the holes from Step S6 by hill sowing. The sowing dose of the mixed seeds is 30 seeds per hole. After hill sowing, cover with the original soil and level the soil.

[0051] Example 3

[0052] This embodiment provides an overall process for a three-dimensional coupled water retention and moisture conservation method for coal mine spoil heaps in sandy wastelands.

[0053] Step S1: Mix straw (35% ± 0.1%) and peat (65% ± 0.1%) together and mix for 20 minutes using a mixer;

[0054] Step S2: Mix the mixture obtained in step S1 with earthworm castings at a ratio of 70%:30% and mix for 20 minutes using a mixer.

[0055] Step S3: Grind the mixture obtained in step S2 for 35 minutes and then screen out the material with a particle size of 0.40±0.01mm;

[0056] Step S4: The mixture obtained in step S3 is subjected to high-level acidification treatment under constant temperature and pressure in a spherical reactor with a radius of 7m. The acidification treatment time is 410±5 minutes, the constant temperature is 82℃±0.5℃, the constant pressure is 1.62±0.05MPa, and the acidification reaction reagent is wood vinegar (pH 3.6±0.01) with an addition ratio of 12%±0.05%.

[0057] Step S5: The product obtained in step S4 is pressed into spherical structures with a diameter of 9mm ± 0.05mm using a granulator. The final product is a new soil activator.

[0058] Step S6: Drill holes on the surface of the open-pit coal mine spoil heap in the sandy wasteland. The holes should form a 50° angle with the ground, with a diameter of 7cm ± 0.5cm and a depth of 8cm ± 0.05cm. The drilling density should be 100 ± 2 holes / m². 2 Then fill the holes with the product obtained in step S5.

[0059] Step S7: Mix the new sand-resistant plants, Leymus chinensis and Apocynum venetum, in a 7:4 ratio and sow them in the holes from Step S6 using a hole-sowing method. The mixed seed sowing dosage is 33 seeds per hole. After hole sowing, cover with the original soil and level the soil.

[0060] The above description is merely a preferred embodiment of the present invention and does not limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter alterations to these embodiments within the spirit and principles of the present invention, achieved through conventional substitutions or by achieving the same function without departing from the principles and spirit of the present invention, fall within the scope of protection of the present invention.

Claims

1. A three-dimensional coupled water retention and moisture conservation method for coal mine spoil heaps in sandy wasteland, characterized in that, The method includes: Step S1: Mix straw and peat in a ratio of (25%-35%):(65%-75%) and mix for 10-20 minutes using a mixer; Step S2: Mix the mixture obtained in step S1 with earthworm castings at a ratio of (60%-70%):(30%-40%) and mix for 10-20 minutes using a mixer. Step S3: Grind the mixture obtained in step S2 for 25-35 minutes, and then screen out materials with a particle size of 0.30mm-0.40mm. Step S4: The mixture obtained in step S3 is subjected to high-level acidification treatment at a constant temperature of 79℃-82℃ and a constant pressure of 1.58MPa-1.62MPa in a spherical reactor with a radius of 5m-7m for 390-410 minutes. The acidification reaction reagent is wood vinegar, and the reaction reagent is added at a ratio of 10%-12%. Step S5: The product obtained in step S4 is pressed into spherical structures with a diameter of 7mm-9mm using a granulator. The final product is a new soil activator. Step S6: Drill holes on the surface of the open-pit coal mine spoil heap in the sandy wasteland. The holes should be 7cm-9cm in diameter and 6cm-8cm deep, forming an angle of 40°-50° with the ground. Drill up to 60 holes per meter. 2 -100 pieces / m 2 After determining the density, the product obtained in step S5 is then filled into the pores. Step S7: Use a novel sand-resistant plant, Leymus chinensis and Apocynum venetum, in a ratio of 2:1 to 3:2, and sow them in the holes of Step S6 by hole sowing. The mixed seed sowing dosage is 30-35 seeds per hole; forming a vegetation-soil synergistic remediation system of "activator improvement - sand-resistant herb cover - root integration".

2. The method for three-dimensional coupling water retention and moisture conservation in a coal mine spoil heap in sandy wasteland according to claim 1, characterized in that, When the peat and straw are mixed in a ratio of (25%-35%):(65%-75%), the straw will quickly disperse when it comes into contact with water, and the activator can quickly combine with the coal mine spoil heap in the sandy wasteland, which can stimulate the metabolism of microorganisms to produce activating substances such as superoxide dehydrogenase.

3. The method for three-dimensional coupling water retention and moisture conservation in a coal mine spoil heap in sandy wasteland according to claim 1, characterized in that, The vegetation-soil synergistic remediation technology system of "activator improvement - sand-resistant herbaceous cover - root system integration" has the ability to continuously remediate coal mine spoil heaps in sandy wastelands.

4. The method for three-dimensional coupling water retention and moisture conservation in a coal mine spoil heap in sandy wasteland according to claim 1, characterized in that, The wood vinegar solution has a retardation effect on heavy metal ions in peat and earthworm castings under a constant temperature of 79℃-82℃ and a constant pressure of 1.58MPa-1.62MPa. It transforms the free state that can be absorbed by plants into a fixed state that cannot be absorbed, reduces the activity of chromium, copper, and zinc, and removes the ecological risks of soil activators.

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