Preparation method of porous solid waste plant-growing substrate, in-situ ecological restoration integrated system and application of porous solid waste plant-growing substrate

Abstract

The invention discloses a preparation method of a porous solid waste vegetation substrate, an in-situ ecological restoration integrated system and application of the porous solid waste vegetation substrate, and the preparation method comprises the following steps: foaming an anionic surfactant solution, mixing the foamed anionic surfactant solution with phosphogypsum to reduce the volume weight and increase the specific surface area of water and fertilizer retention, sequentially adding an alkaline conditioner for harmless treatment, and then adding a water-retaining agent; the method comprises the following steps: adding decomposed biomass to provide organic matters, conditioning the humidity by using a water-retention agglomerating agent polyacrylamide solution, granulating and forming, promoting further decomposition of the decomposed biomass by using a synergistic nitrogen fixation effect of nodule bacteria and alfalfa, and reducing the application cost of the nitrogen fertilizer. The porous solid waste vegetation substrate prepared by the method has proper size fraction structure, pore structure and nutrient content, can effectively promote plant growth, realizes resource utilization of ardealite, realizes continuous operation of waste ardealite in-situ treatment and ecological restoration by combining with the integrated system provided by the invention, and has good application prospects. The transportation cost of the solid waste and the risk of secondary pollution are reduced, and the working efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization and ecological restoration materials technology, and specifically relates to an integrated system for the preparation of porous solid waste vegetation substrate and in-situ ecological restoration, as well as its application. Background Technology

[0002] Phosphogypsum is a solid waste generated during the wet-process phosphoric acid production process, producing approximately 5 tons of phosphogypsum for every ton of phosphoric acid produced. Currently, the amount of phosphogypsum stockpiled is enormous, but its comprehensive utilization rate remains low. The vast majority is still disposed of through open-air stockpiling. This method not only occupies a large amount of land resources, but also allows impurities such as soluble phosphorus, soluble fluorine, trace heavy metals, and acidic substances contained in the phosphogypsum to easily leach into the surrounding soil and water bodies through rainwater, causing environmental pollution. Therefore, there is an urgent need to find effective ways to utilize this resource.

[0003] Currently, the resource utilization of phosphogypsum is mainly concentrated in the building materials and agricultural sectors. However, these applications all have certain limitations. In building materials, impurities in phosphogypsum can affect the performance of building materials, and its application market is limited by geographical location and transportation radius, making it difficult to absorb large quantities of stockpiled phosphogypsum on a large scale. In agricultural applications, although phosphogypsum itself contains nutrients such as calcium and sulfur, its acidic substances, soluble fluorine, and heavy metals pose a risk of migration and accumulation of pollutants into crops if applied directly or after simple treatment to the soil. The long-term environmental safety of its use remains questionable, severely limiting its direct application in agriculture and ecology.

[0004] Especially in ecological restoration projects such as slope ecological restoration and mine reclamation, topsoil spraying is a commonly used technique. However, this technique requires the extraction of large amounts of high-quality topsoil, which is costly and damages the ecological environment of the extraction site. At the same time, ordinary topsoil substrates after spraying often have problems such as poor structural stability, easy soil erosion, and insufficient water and fertilizer retention capacity, which affect the rapid establishment and long-term stability of vegetation.

[0005] Therefore, there is an urgent need to develop a method for preparing porous solid waste vegetation substrate to dispose of waste phosphogypsum on a large scale and convert it into a vegetation substrate suitable for ecological restoration, thereby realizing the resource utilization of waste phosphogypsum and alleviating the environmental pressure caused by the stockpiling of waste phosphogypsum. Summary of the Invention

[0006] The purpose of this invention is to provide an integrated system for the preparation of porous solid waste vegetation substrate and in-situ ecological restoration, as well as its application, so as to solve at least one of the above-mentioned technical problems.

[0007] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a porous solid waste vegetative substrate, the method comprising: S1, adding water to an anionic surfactant to prepare a solution, and foaming the solution using a foaming machine to obtain foam; S2, mixing the foam with waste phosphogypsum at a mass ratio of 1:4 to obtain foamed phosphogypsum; S3, adding an alkaline conditioner to the foamed phosphogypsum, and stirring evenly to obtain harmless phosphogypsum; S4, adding composted biomass to the harmless phosphogypsum, and stirring evenly to obtain organic phosphogypsum; S5, dissolving polyacrylamide in water and adding it to the organic phosphogypsum, mixing evenly, wherein the water content of the mixture is 30%-35%; S6, transferring the mixture to a granulator for granulation to obtain a porous solid waste vegetative substrate.

[0008] In the first aspect, the particle size distribution of the porous solid waste vegetation substrate is as follows: 10% by mass in the range of 0.074mm ≤ d < 0.5mm; 20% by mass in the range of 0.5mm ≤ d < 1.0mm; 50% by mass in the range of 1.0mm ≤ d < 2.0mm; and 20% by mass in the range of 2.0mm ≤ d ≤ 5.0mm; wherein d is the particle size of the porous solid waste vegetation substrate.

[0009] In the first aspect, in step S1, the concentration of the solution is 300-700 mg / L; the volume of the foam is 3-5 times the volume of the solution; and the anionic surfactant includes at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and sodium fatty alcohol polyoxyethylene ether sulfate.

[0010] In the first aspect, the amount of alkaline conditioning agent added is 0.5% of the mass of the foamed phosphogypsum; the alkaline conditioning agent includes at least one of quicklime, carbide slag and steel slag.

[0011] In the first aspect, the amount of the composted biomass added is 3%-5% of the mass of the foamed phosphogypsum; the composted biomass includes at least one of composted pine needles, composted rice husks, and composted straw.

[0012] In the first aspect, the amount of polyacrylamide added is 0.05% of the mass of the waste phosphogypsum.

[0013] The second aspect of the present invention provides a porous solid waste vegetation substrate, which is prepared by the method for preparing porous solid waste vegetation substrate described in the first aspect.

[0014] The third aspect of this invention provides an application of porous solid waste vegetation substrate in ecological restoration, the application comprising the following steps: laying a 50cm high vegetation layer on the land to be restored, the vegetation layer being the porous solid waste vegetation substrate described in the second aspect; and applying compound fertilizer at a spreading rate of 30-50g / m². 2 The seeds are evenly sown on the vegetation layer, and the first tillage is performed to a depth of 5-10 cm. The compound fertilizer contains nitrogen, potassium, and organic matter. The grass seeds are sown at a rate of 150 g / m². 2 The seeds are evenly sown on the vegetation layer after the first tillage, and then tilled a second time to a depth of 2-5 cm. The grass seed is a mixture of ryegrass, tall fescue, and alfalfa in a mass ratio of 4:4:3. The compound microbial agent solution is sprayed at a rate of 1 L / m². 2 The compound microbial agent solution is evenly sprayed onto the vegetation layer after the second tillage. The mass ratio of rhizobium to Bacillus subtilis in the compound microbial agent solution is 1:1, and the concentration of the compound microbial agent solution is 1g / 100mL. After spraying, the land is maintained to complete the vegetation ecological restoration of the land to be restored.

[0015] A fourth aspect of this invention provides an integrated system for in-situ ecological restoration of porous solid waste vegetative substrates. The system includes: a walking module comprising a walking section and a support platform, the support platform being mounted on the walking section; and a phosphogypsum collection and pretreatment module comprising a pre-scraper collector, a crushing and screening machine, and a metering feeder. The pre-scraper collector is connected to the inlet of the crushing and screening machine via a conveyor belt, and the outlet of the crushing and screening machine is connected to the inlet of the metering feeder. The pre-scraper collector is used to collect waste phosphogypsum, and the pre-scraper collector and the crushing and screening machine... Fixed to the support platform; the online mixing and modification module includes a surfactant foaming device, an alkaline conditioner addition chamber, an organic matter addition chamber, a binder addition chamber, and a biaxial spiral dynamic mixer; the surfactant foaming device includes a solution preparation tank and a high-pressure foaming machine, the high-pressure foaming machine being used to foam the solution in the solution preparation tank; the outlet of the solution preparation tank is connected to the first section of the biaxial spiral dynamic mixer, and the outlet of the metering feed device is connected to the inlet of the biaxial spiral dynamic mixer; the outlet of the alkaline conditioner addition chamber is connected to the biaxial spiral dynamic mixer. The second section of the mixer is connected; the outlet of the organic matter addition chamber is connected to the third section of the twin-screw dynamic mixer; the outlet of the binder addition chamber is connected to the fourth section of the twin-screw dynamic mixer; the twin-screw dynamic mixer is fixed to the support platform; the granulation and spreading module includes an adjustable-angle granulation disc, a substrate spreader, and a seed-fertilizer-microbe compound spreading device. The inlet of the adjustable-angle granulation disc is connected to the outlet of the twin-screw dynamic mixer, and the outlet of the adjustable-angle granulation disc is connected to the substrate spreader. The substrate spreader is used to spread the substrate on the land to be restored. A vegetation layer is provided; the seed-fertilizer-microorganism compound spreading device includes several independent storage chambers for storing grass seeds, compound fertilizer, and microbial agents, and each storage chamber is equipped with a meter for calculating the spreading amount; the tilt-adjustable granulation disc is fixed on the support platform; an intelligent control module is used to control the walking module, the phosphogypsum collection and pretreatment module, the online mixing and modification module, and the granulation and spreading module to achieve continuous operation; wherein, the vegetation layer is the porous solid waste vegetation substrate described in the second aspect, and the porous solid waste vegetation substrate is formed in the tilt-adjustable granulation disc.

[0016] In the fourth aspect, the system further includes a pre-dust suppression spray device and a post-dust suppression spray device; the pre-dust suppression spray device is fixed on the conveyor belt; and the post-dust suppression spray device is fixed on the support platform.

[0017] Beneficial effects: This invention provides a method for preparing a porous solid waste vegetative substrate. First, an anionic surfactant is dissolved in water and foamed using a foaming machine to obtain a large amount of fine, uniform, and stable foam. The obtained foam is then mixed with waste phosphogypsum at a mass ratio of 1:4, ensuring the foam is evenly dispersed between the phosphogypsum particles. This introduces a large number of air pores into the originally dense phosphogypsum, resulting in loose and porous foamed phosphogypsum. This promotes the dissolution of phosphorus and fluorine from the phosphogypsum and reduces its bulk density. Then, [the method involves adding...] An alkaline conditioner is added to neutralize the acidic substances in the phosphogypsum and fix the dissolved phosphorus and nitrogen, forming harmless phosphogypsum. Next, decomposed biomass is added to the harmless phosphogypsum to improve the organic nutrient status of the phosphogypsum and further reduce its bulk density, resulting in organic phosphogypsum. Finally, polyacrylamide is added to the organic phosphogypsum to enhance its water and fertilizer retention capacity and control the moisture content to 30%-50%, which is beneficial for maintaining the granulation shape and stability in the granulator, thereby obtaining a porous solid waste vegetation substrate with good particle size distribution. This invention uses waste phosphogypsum as the main raw material to prepare a porous solid waste vegetative substrate. By adding foam made of anionic surfactant to the waste phosphogypsum, the porosity of the vegetative substrate is increased, allowing the subsequently added alkaline conditioner to more fully contact and fix harmful impurities. After adding decomposed biomass and polyacrylamide, the organic nutrients and water and fertilizer retention capacity of the vegetative substrate are improved, providing continuous and stable nutrients and water for plant growth. It can be widely used in slope restoration, mine ecological restoration, saline-alkali land improvement and desert control and other restoration scenarios.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of a method for preparing a porous solid waste vegetation substrate according to the present invention; Figure 2 This is a modular schematic diagram of an integrated system for in-situ ecological restoration of porous solid waste vegetation substrate, as described in this invention. Detailed Implementation

[0021] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0022] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0023] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be obtained by purchasing them from the market or by existing methods.

[0024] Please see Figure 1 This invention provides a method for preparing a porous solid waste vegetative substrate, the method comprising: S1, adding water to an anionic surfactant to prepare a solution, and foaming the solution using a foaming machine to obtain foam; S2, mixing the foam with waste phosphogypsum at a mass ratio of 1:4 to obtain foamed phosphogypsum; S3, adding an alkaline conditioner to the foamed phosphogypsum, and stirring evenly to obtain harmless phosphogypsum; S4, adding composted biomass to the harmless phosphogypsum, and stirring evenly to obtain organic phosphogypsum; S5, dissolving polyacrylamide in water and adding it to the organic phosphogypsum, mixing evenly, wherein the water content of the mixture is 30%-35%; S6, transferring the mixture to a granulator for granulation to obtain a porous solid waste vegetative substrate.

[0025] Specifically, this invention provides a method for preparing a porous solid waste vegetative substrate. First, an anionic surfactant is dissolved in water and foamed using a foaming machine to obtain a large amount of fine, uniform, and stable foam. The obtained foam is then mixed with waste phosphogypsum at a mass ratio of 1:4, ensuring the foam is evenly dispersed between the phosphogypsum particles. This introduces a large number of air pores into the originally dense phosphogypsum, resulting in loose and porous foamed phosphogypsum. This promotes the dissolution of phosphorus and fluorine from the phosphogypsum and reduces its bulk density. Then, the foamed phosphogypsum... An alkaline conditioner is added to the phosphogypsum to neutralize the acidic substances and fix the dissolved phosphorus and nitrogen, forming harmless phosphogypsum. Next, decomposed biomass is added to the harmless phosphogypsum to improve its organic nutrient status and further reduce its bulk density, resulting in organic phosphogypsum. Finally, polyacrylamide is added to the organic phosphogypsum to enhance its water and fertilizer retention capacity and control the moisture content to 30%-50%, which is beneficial for maintaining the granulation shape and stability in the granulator, thereby obtaining a porous solid waste vegetation substrate with good particle size distribution. This invention uses waste phosphogypsum as the main raw material to prepare a porous solid waste vegetative substrate. By adding foam made of anionic surfactant to the waste phosphogypsum, the porosity of the vegetative substrate is increased, allowing the subsequently added alkaline conditioner to more fully contact and fix harmful impurities. After adding decomposed biomass and polyacrylamide, the organic nutrients and water and fertilizer retention capacity of the vegetative substrate are improved, providing continuous and stable nutrients and water for plant growth. It can be widely used in slope restoration, mine ecological restoration, saline-alkali land improvement and desert control and other restoration scenarios.

[0026] In some possible embodiments, the particle size distribution of the porous solid waste vegetation substrate is as follows: 10% by mass in the range of 0.074mm ≤ d < 0.5mm; 20% by mass in the range of 0.5mm ≤ d < 1.0mm; 50% by mass in the range of 1.0mm ≤ d < 2.0mm; and 20% by mass in the range of 2.0mm ≤ d ≤ 5.0mm; wherein d is the particle size of the porous solid waste vegetation substrate.

[0027] In this application, a mixture with a moisture content of 30%-50% is granulated in a granulator to form a porous solid waste vegetative substrate with different particle sizes, and these particles are combined in a certain proportion. The interlocking of particles of different sizes improves the stability and erosion resistance of the vegetative substrate, while also ensuring good permeability and aeration. The porous solid waste vegetative substrate with the particle size distribution provided in this application has good flowability, is not prone to clumping, and can be operated with a hydroseeding machine, improving construction efficiency and quality. It also promotes plant root growth, allowing plant roots to extend downwards and outwards through the gaps between particles.

[0028] In some possible embodiments, in step S1, the concentration of the solution is 300-700 mg / L; the volume of the foam is 3-5 times the volume of the solution.

[0029] In some possible embodiments, the anionic surfactant includes at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and sodium fatty alcohol polyoxyethylene ether sulfate.

[0030] In this application, anionic surfactants are first dissolved in water to prepare a solution with a concentration of 300-700 mg / L. The solution is then foamed to 3-5 times its original volume using a foaming machine. Under the action of the foaming machine, air is introduced into the solution, and the anionic surfactants quickly encapsulate the air bubbles, forming a large number of fine, uniform, and stable foams, which form the basis for subsequent mixing with phosphogypsum to construct a porous structure.

[0031] In some possible embodiments, the amount of alkaline conditioner added is 0.5% of the mass of the foamed phosphogypsum; the alkaline conditioner includes at least one of quicklime, carbide slag and steel slag.

[0032] Those skilled in the art will understand that using industrial wastes such as quicklime, carbide slag, and steel slag as alkaline conditioning agents embodies the environmental protection concept of "treating waste with waste." At the same time, it can neutralize the acidic substances in phosphogypsum, and the calcium ions it contains can efficiently fix soluble phosphorus and nitrogen to form stable precipitates, thus achieving the harmless treatment of phosphogypsum.

[0033] In some possible embodiments, the amount of composted biomass added is 3%-5% of the mass of the foamed phosphogypsum; the composted biomass includes at least one of composted pine needles, composted rice husks, and composted straw.

[0034] Specifically, decomposed biomass such as decomposed pine needles, decomposed rice husks, and decomposed straw are common agricultural wastes that are widely available and inexpensive. When added to phosphogypsum as organic matter, they not only provide slow-release nutrients but also improve the granular structure of the vegetation substrate, enhance water and fertilizer retention capacity, and further reduce the overall bulk density, thus facilitating mechanized spraying and creating a suitable growth environment for microorganisms and plant roots.

[0035] In some possible embodiments, the amount of polyacrylamide added is 0.05% of the mass of the waste phosphogypsum.

[0036] In this application, by adding polyacrylamide and controlling the moisture content, the mixture has excellent water stability in the granulator, thereby obtaining a vegetation substrate with ideal particle size distribution, ensuring the success rate of granulation and the roundness of the particles. Furthermore, the vegetation substrate is not easy to disintegrate or disperse after contact with water, which is beneficial to prevent soil erosion after hydroseeding.

[0037] Based on a general inventive concept, the second aspect of the present invention provides a porous solid waste vegetation substrate, which is prepared by the method for preparing porous solid waste vegetation substrate described in the first aspect.

[0038] In this application, the porous solid waste vegetative substrate prepared by the preparation method of the first aspect has low bulk density, good water permeability, water retention and water temperature properties, and a porosity as high as 30%-50%, which is beneficial to plant root growth and water and fertilizer retention.

[0039] Based on a general inventive concept, the third aspect of this invention provides an application of porous solid waste vegetation substrate in ecological restoration, the application comprising the following steps: laying a 50cm high vegetation layer on the land to be restored, the vegetation layer being the porous solid waste vegetation substrate described in the second aspect; and applying compound fertilizer at a spreading rate of 30-50g / m². 2 The seeds are evenly sown on the vegetation layer, and the first tillage is performed to a depth of 5-10 cm. The compound fertilizer contains nitrogen, potassium, and organic matter. The grass seeds are sown at a rate of 150 g / m². 2 The seeds are evenly sown on the vegetation layer after the first tillage, and then tilled a second time to a depth of 2-5 cm. The grass seed is a mixture of ryegrass, tall fescue, and alfalfa in a mass ratio of 4:4:3. The compound microbial agent solution is sprayed at a rate of 1 L / m². 2 The compound microbial agent solution is evenly sprayed onto the vegetation layer after the second tillage. The mass ratio of rhizobium to Bacillus subtilis in the compound microbial agent solution is 1:1, and the concentration of the compound microbial agent solution is 1g / 100mL. After spraying, the land is maintained to complete the vegetation ecological restoration of the land to be restored.

[0040] The applications include slope restoration, mine ecological restoration, saline-alkali land improvement, or desert restoration.

[0041] Specifically, this invention constructs a plant-microbe synergistic restoration ecosystem. By combining ryegrass, tall fescue, and alfalfa in specific proportions and adding rhizobia, nitrogen fixation by alfalfa is promoted, thereby boosting the growth of tall fescue and ryegrass. Simultaneously, alfalfa's nitrogen fixation also promotes the degradation of residual cellulose and other organic matter in decomposed biomass by Bacillus subtilis, accelerating the maturation process of the solid waste vegetative substrate soil and increasing the abundance and activity of soil microorganisms, forming a virtuous cycle. Furthermore, the porous solid waste vegetative substrate contains phosphorus, and the nitrogen fixation of alfalfa reduces the need for nitrogen and phosphorus fertilizer supplementation during subsequent vegetation maintenance.

[0042] In summary, the preparation method provided by this invention includes: foaming an anionic surfactant solution and mixing it with phosphogypsum to reduce bulk density and increase water- and fertilizer-retaining surface area; sequentially adding an alkaline conditioner for harmless treatment; adding decomposed biomass to provide organic matter; then conditioning the humidity with a water-retaining agglomerating agent polyacrylamide solution before granulation; and utilizing the synergistic nitrogen-fixing effect of rhizobia and alfalfa to further decompose the decomposed biomass and reduce the cost of nitrogen fertilizer application. The porous solid waste vegetative substrate prepared by this invention has suitable particle size distribution, pore structure, and nutrient content, which can effectively promote plant growth, realize the resource utilization of phosphogypsum, and can be widely used in ecological environment construction projects such as slope restoration and mine ecological restoration, with significant environmental and economic benefits.

[0043] Based on a general inventive concept, please refer to... Figure 2The fourth aspect of this invention provides an integrated system for in-situ ecological restoration of porous solid waste vegetative substrates. The system includes: a walking module comprising a walking section and a support platform, the support platform being mounted on the walking section; and a phosphogypsum collection and pretreatment module comprising a pre-scraper collector, a crushing and screening machine, and a metering feeder. The pre-scraper collector is connected to the inlet of the crushing and screening machine via a conveyor belt, and the outlet of the crushing and screening machine is connected to the inlet of the metering feeder. The pre-scraper collector is used to collect waste phosphogypsum, and the pre-scraper collector and the crushing and screening machine... The machine is fixed on the support platform; the online mixing and modification module includes a surfactant foaming device, an alkaline conditioner addition chamber, an organic matter addition chamber, a binder addition chamber, and a twin-screw dynamic mixer; the surfactant foaming device includes a solution preparation tank and a high-pressure foaming machine, the high-pressure foaming machine being used to foam the solution in the solution preparation tank; the outlet of the solution preparation tank is connected to the first section of the twin-screw dynamic mixer, and the outlet of the metering feed device is connected to the inlet of the twin-screw dynamic mixer; the outlet of the alkaline conditioner addition chamber is connected to the twin-screw dynamic mixer. The second section of the mixer is connected; the outlet of the organic matter addition chamber is connected to the third section of the twin-screw dynamic mixer; the outlet of the binder addition chamber is connected to the fourth section of the twin-screw dynamic mixer; the twin-screw dynamic mixer is fixed to the support platform; the granulation and spreading module includes an adjustable-angle granulation disc, a substrate spreader, and a seed-fertilizer-microbe composite spreading device, wherein the inlet of the adjustable-angle granulation disc is connected to the outlet of the twin-screw dynamic mixer, and the outlet of the adjustable-angle granulation disc is connected to the substrate spreader, which is used to spread the substrate on the land to be restored. A vegetation layer is laid; the seed-fertilizer-microorganism compound spreading device includes several independent storage chambers for storing grass seeds, compound fertilizer, and microbial agents, and each storage chamber is equipped with a meter for calculating the spreading amount; the tilt-adjustable granulation disc is fixed on the support platform; an intelligent control module is used to control the walking module, the phosphogypsum collection and pretreatment module, the online mixing and modification module, and the granulation and spreading module to achieve continuous operation; wherein, the vegetation layer is the porous solid waste vegetation substrate described in the second aspect, and the porous solid waste vegetation substrate is formed in the tilt-adjustable granulation disc.

[0044] The system also includes a pre-dust suppression spray device and a post-dust suppression spray device; the pre-dust suppression spray device is fixed on the conveyor belt; the post-dust suppression spray device is fixed on the support platform.

[0045] Specifically, this invention provides an integrated system for in-situ ecological restoration of porous solid waste vegetative substrates, comprising a walking module, a phosphogypsum collection and pretreatment module, an online mixing and modification module, a granulation and spreading module, and an intelligent control module. The walking module includes a walking section and a support platform, with the support platform mounted on the walking section, allowing the integrated system to be directly moved to the work site. The phosphogypsum collection and pretreatment module includes a pre-scraper collector, a crushing and screening machine, and a metering and feeding device. The pre-scraper collector collects waste phosphogypsum in situ, which is then conveyed by a conveyor belt to the crushing and screening machine for crushing. After crushing, the phosphogypsum is conveyed by the metering and feeding device to a twin-screw dynamic mixer, where it is combined with a surfactant foaming device. The prepared foam is used to prepare foamed phosphogypsum in the first section of a biaxial spiral dynamic mixer; alkaline conditioner is added to the second section of the biaxial spiral dynamic mixer through an alkaline conditioner addition bin to prepare harmless phosphogypsum; decomposed biomass is added to the third section of the biaxial spiral dynamic mixer through an organic matter addition bin to prepare organic phosphogypsum; binder is added to the fourth section of the biaxial spiral dynamic mixer through a binder addition bin and mixed evenly, then conveyed to an adjustable tilting granulation tray for granulation to obtain a porous solid waste vegetative substrate. Then, the porous solid waste vegetative substrate is spread onto the land to be remediated through a substrate spreader, followed by the sequential spreading of grass seeds, compound fertilizer and microbial agents, and water spraying for maintenance to complete the continuous remediation operation of the land to be remediated. This invention integrates the treatment and ecological restoration of waste phosphogypsum, realizing a fully integrated operation from phosphogypsum collection to vegetation establishment, which greatly improves work efficiency, reduces phosphogypsum transportation costs, and effectively controls dust diffusion during the operation by combining pre-dust suppression spray devices and post-dust suppression spray devices, thus reducing the impact on the environment.

[0046] In this application, the front-mounted scraper collector employs a hydraulically controlled, liftable design, with a collection width of 2-3m and a collection depth of 10-50cm. The collected waste phosphogypsum is crushed in a crushing and screening machine to obtain phosphogypsum particles with a particle size ≤5mm. A twin-shaft spiral dynamic mixer ensures that the crushed waste phosphogypsum is thoroughly mixed sequentially with surfactants, alkaline conditioners, composted biomass, and binders, facilitating granulation. The substrate spreader uses a hydraulically controlled scraper structure to control the thickness of the vegetation layer. The intelligent control module, developed based on industrial PLC and IoT technology, includes a GPS positioning module, a vision recognition module, and an automatic control module, enabling autonomous navigation, automatic adjustment of process parameters, and obstacle avoidance.

[0047] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0048] Example 1 This embodiment provides a method for preparing a porous solid waste vegetation substrate, which specifically includes the following steps: (1) Weigh 500mg of industrial grade sodium dodecyl sulfate and dissolve it in 1L of water to prepare a solution with a concentration of 500mg / L. Transfer the solution to a foaming machine and foam it to 4 times the volume of the solution to obtain foam with good stability. (2) Weigh 10 kg of foam and add 40 kg of waste phosphogypsum with a moisture content of 15%. Stir in a mixer at a speed of 60 r / min for 5 min to make the foam evenly coat the phosphogypsum particles and obtain foamed phosphogypsum. (3) Weigh 250g of quicklime (which is 0.5% of the mass of foamed phosphogypsum), add it to the foamed phosphogypsum and continue stirring for 3 minutes to make the quicklime and foamed phosphogypsum evenly mixed to obtain harmless phosphogypsum. (4) Weigh 2 kg of decomposed pine needles (which is 4% of the mass of foamed phosphogypsum), add them to the harmless phosphogypsum and continue stirring for 5 minutes to make the decomposed pine needles and harmless phosphogypsum evenly mixed to obtain organic phosphogypsum. (5) Weigh 2g of polyacrylamide (which is 0.05% of the mass of waste phosphogypsum) and dissolve it in 100mL of water. Add it to the organic phosphogypsum, mix well, and add water so that the water content of the mixture of polyacrylamide and organic phosphogypsum is 32%. (6) The mixture is transferred to a disc granulator with an inclination angle of 25°. By adjusting the rotation speed and discharge time of the disc granulator, a porous solid waste plant substrate with good particle size distribution is obtained. Its porosity is 38.2%, and it has a light bulk density and good water and fertilizer retention effect. The particle size distribution is as follows: the mass proportion between 0.074mm≤d<0.5mm is 10%; the mass proportion between 0.5mm≤d<1.0mm is 20%; the mass proportion between 1.0mm≤d<2.0mm is 50%; and the mass proportion between 2.0mm≤d≤5.0mm is 20%.

[0049] The porous solid waste vegetative substrate prepared above is used for ecological restoration. The specific steps are as follows: First, a 50cm high vegetative layer of the prepared porous solid waste vegetative substrate is laid on the land to be restored; second, a compound fertilizer with a nitrogen content greater than 15%, a phosphorus content greater than 15%, a potassium content greater than 10%, and an organic matter content greater than 45% is selected and broadcast at a rate of 40g / m². 2 Evenly sow the seeds on the surface of the vegetative substrate and till them to a depth of 5-10 cm using a rake; then, apply a mixture of ryegrass, tall fescue, and alfalfa at a mass ratio of 4:4:3 at a rate of 150 g / m². 2 The seeding agent is evenly spread on the surface and then raked to a depth of 2-5 cm. Finally, a compound inoculant of rhizobium and Bacillus subtilis (both with a viable count of 1 billion U / g) is mixed at a 1:1 mass ratio. 1g of the mixed inoculant is dissolved in 100mL of water to prepare a compound inoculant solution, and this solution is applied at a rate of 1L / m³. 2 Spray the appropriate amount onto the surface; for the first two weeks after sowing, water every two days to keep the substrate surface moist. After 15 days, the grass seeds will begin to emerge, and after 30 days, the coverage will reach more than 70%.

[0050] Furthermore, to verify the effectiveness of the product of this invention, a 60-day plant growth experiment was conducted. The experimental group used the porous solid waste vegetative substrate prepared according to this invention, while the control group used conventional topsoil. The topsoil was taken from the surface covering soil of a phosphogypsum warehouse in Hubei Province, and its basic physicochemical properties were: pH 6.2, organic matter content 1.8%, available phosphorus content 18.5 mg / kg, available potassium content 125.3 mg / kg, and bulk density 1.35 g / cm³. 3 .

[0051] The results showed that the germination rates of ryegrass, tall fescue, and alfalfa in the experimental group were 92%, 89%, and 90%, respectively, significantly higher than those in the control group (75%, 78%, and 72%). After 60 days, the average biomass of the plants in the experimental group was 35% higher than that in the control group, and the root length was 40% longer. These results indicate that the porous solid waste vegetative substrate prepared in this invention can not only effectively utilize phosphogypsum, an industrial solid waste, but also provide an excellent substrate environment for plant growth, showing broad application prospects in the field of ecological restoration.

[0052] Comparative Example 1 The difference between the preparation method of the porous solid waste vegetative substrate in this comparative example and that in Example 1 is that: instead of using a foaming machine for foaming, 10 kg of sodium dodecyl sulfate solution with a concentration of 500 mg / L is directly weighed and mixed evenly with 40 kg of waste phosphogypsum with a water content of 15%. The porosity of the porous solid waste vegetation substrate prepared in this comparative example was found to be 19.5%.

[0053] The porous solid waste vegetation substrate prepared in Comparative Example 1 was applied for ecological restoration according to the steps in Example 1. After 60 days, the germination rates of ryegrass, tall fescue and alfalfa were 65%, 62% and 58% respectively, and the overall vegetation rate was only 70%.

[0054] Comparative Example 2 The difference between the preparation method of the porous solid waste vegetative substrate in this comparative example and that in Example 1 is that: no anionic surfactant is added, and 10 kg of pure water and 40 kg of waste phosphogypsum with a water content of 15% are directly weighed and mixed evenly; wherein, the foam generated by foaming pure water has extremely poor stability. Testing revealed that the porosity of the porous solid waste vegetation substrate prepared in this comparative example was 15.1%; the fluoride leaching amount was higher than that in comparative example 1, but both were within the groundwater requirement range (5 mg / L), which demonstrates the effect of surfactants in promoting fluoride passivation.

[0055] The porous solid waste vegetation substrate prepared in Comparative Example 2 was applied for ecological restoration according to the steps in Example 1. After 60 days, the germination rates of ryegrass, tall fescue and alfalfa were 65%, 62% and 58% respectively, and the overall vegetation rate was only 70%.

[0056] Comparative Example 3 The preparation method of the porous solid waste vegetation substrate in this comparative example is as follows: (1) Weigh 500mg of industrial grade sodium dodecyl sulfate and dissolve it in 1L of water to prepare a solution with a concentration of 500mg / L. Transfer the solution to a foaming machine and foam it to 4 times the volume of the solution to obtain foam with good stability. (2) Weigh 10 kg of foam and add 40 kg of waste phosphogypsum with a moisture content of 15%. Stir in a mixer at a speed of 60 r / min for 5 min to make the foam evenly coat the phosphogypsum particles and obtain foamed phosphogypsum. (3) Weigh 2 kg of decomposed pine needles (which is 4% of the mass of foamed phosphogypsum), add them to the foamed phosphogypsum and continue stirring for 5 minutes to make the decomposed pine needles and foamed phosphogypsum evenly mixed to obtain organic phosphogypsum. (4) Weigh 2g of polyacrylamide (which is 0.05% of the mass of waste phosphogypsum) and dissolve it in 100mL of water. Add it to the organic phosphogypsum, mix well, and add water so that the water content of the mixture of polyacrylamide and organic phosphogypsum is 32%. (5) The mixture is transferred to a disc granulator with an inclination angle of 25° for granulation to obtain porous phosphogypsum particles of different particle sizes; (6) Weigh 250g of quicklime (which is 0.5% of the mass of foamed phosphogypsum), add it to the porous phosphogypsum particles and stir to treat the porous phosphogypsum particles to obtain a porous solid waste plant substrate. Testing revealed that quicklime failed to penetrate evenly into the porous phosphogypsum particles, resulting in a high content of residual acidic substances and soluble impurities in the porous solid waste vegetative substrate. Among these, salts such as phosphorus, fluorine, and sulfate were not passivated and stabilized. Under long-term irrigation-drying or wetting-drying cycles caused by diurnal temperature variations, the salts in the porous solid waste vegetative substrate would continuously migrate to the surface of the substrate due to capillary forces, making the surface prone to salinization and affecting root development. At the same time, the highly alkaline quicklime failed to react fully with the vegetative substrate, resulting in excessively high local alkalinity, which could easily burn seedlings.

[0057] The porous solid waste vegetation substrate prepared in Comparative Example 3 was applied for ecological restoration according to the steps in Example 1. After 60 days, the emergence rates of ryegrass, tall fescue and alfalfa were 45%, 48% and 40% respectively, and the overall vegetation rate was only 41%. Moreover, in the vegetation growth experiment, the emergence was uneven, some seedlings were scorched in the later stage, and white frost appeared on the surface of the vegetation substrate.

[0058] Example 2 This embodiment provides a method for ecological restoration of a phosphogypsum stockpile using the integrated system provided in the fourth aspect of the present invention, covering an area of ​​approximately 50,000 square meters. First, the integrated system is driven to the work area by an intelligent control module, which can autonomously navigate according to a preset work path. A front-mounted scraper collector collects waste phosphogypsum from the surface at a depth of 20 cm, with a collection rate of 8 tons / hour. The collected phosphogypsum is crushed and screened by a crusher and then fed into an online mixing and modification module via a metering feeder. Next, foam is generated in a surfactant foaming device, and the foam is initially mixed with phosphogypsum in the first stage of a twin-screw dynamic mixer to obtain foamed phosphogypsum. This foamed phosphogypsum is then transported to the second stage of the twin-screw dynamic mixer and mixed with added alkaline conditioner (carbide slag) to obtain harmless phosphogypsum. Finally, this harmless phosphogypsum is transported to the third stage of the twin-screw dynamic mixer and mixed with added decomposed pine needles to obtain organic phosphogypsum. The fourth section of the twin-screw dynamic mixer is mixed with the added binder to obtain a mixture. The modification of waste phosphogypsum is completed in the twin-screw dynamic mixer. Then, the modified phosphogypsum mixture is conveyed to the tilt-adjustable granulation tray for granulation to form a porous solid waste vegetation substrate with a particle size of 2-5 mm. Finally, the porous solid waste vegetation substrate is evenly spread on the ground surface through a substrate spreader to form a 50 cm thick vegetation layer. Compound fertilizer (compound fertilizer with nitrogen content greater than 15%, phosphorus content greater than 15%, and organic matter content greater than 45%), grass seeds (ryegrass, tall fescue, and alfalfa in a mass ratio of 4:4:3) and microbial agents (compound microbial agents of rhizobium and Bacillus subtilis in a mass ratio of 1:1) are then sprayed on the vegetation layer and watered for maintenance.

[0059] Fifteen days after construction, grass seeds began to sprout; after 30 days, vegetation coverage reached over 60%; and after 60 days, vegetation coverage reached over 85%. Monitoring data showed that the leaching concentration of heavy metals in the phosphogypsum in the remediated area was below the national standard limit, and vegetation growth was good. The integrated system of this application operates at a speed of 1 km / h, and can remediate an area of ​​8,000 square meters per day working 8 hours, with a remediation efficiency more than 5 times that of traditional methods and a cost reduction of more than 40%.

[0060] In summary, compared with the prior art, the present invention has the following advantages: (1) This invention uses phosphogypsum as the main raw material, which is consumed in large quantities. It not only solves the environmental problems caused by phosphogypsum stockpiling, but also produces ecological restoration materials with economic value, thus achieving a balance between environmental and economic benefits. (2) By foaming anionic surfactants, the present invention promotes the dissolution of phosphorus and fluorine in waste phosphogypsum and enables alkaline conditioners to fix more phosphorus and fluorine, thereby improving the deep solidification effect of alkaline conditioners.

[0061] (3) The porous structure formed by the foaming and granulation process of this invention reduces the bulk density of the plant substrate and has good permeability, water retention and water stability. The porosity is as high as 30-50%, which is beneficial to plant root growth and water and fertilizer retention.

[0062] (4) The present invention uses ryegrass, tall fescue and alfalfa for planting, and adds rhizobia to promote nitrogen fixation of alfalfa, promote the growth of ryegrass and tall fescue, and promote the decomposition of decomposed biomass, further promoting the diversity of substrate microorganisms and forming a positive cycle.

[0063] (5) The porous solid waste plant substrate prepared by the present invention has a strong water retention capacity and can continuously replenish water to seeds and roots; it provides a good habitat for plant beneficial microorganisms, promotes the recruitment of microorganisms by roots, and forms a good micro-ecological accelerator; it promotes the increase of microbial diversity and further promotes the inorganic-organic fertility conversion; it has a strong fertility retention capacity and avoids loss due to irrigation or rainwater, and can continuously replenish water to seeds and roots.

[0064] (6) The porous solid waste vegetative substrate prepared by this invention has a germination rate of over 90% and a biomass that is more than 30% higher than that of ordinary soil. It can be used in various scenarios such as slope restoration, mine ecological restoration, saline-alkali land improvement and desert control, and has broad application prospects.

[0065] (7) The integrated system provided by the present invention has an operating speed of 0.5-2 km / h, a phosphogypsum treatment capacity of 5-10 tons / hour, and a daily repair area of ​​2000-5000 square meters.

[0066] Finally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0067] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0068] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method of preparing a porous solid waste phytogenic substrate, characterized in that, The preparation method comprises: S1, water is added to an anionic surfactant to prepare a solution, the solution is foamed by a foaming machine to obtain a foam; S2, the foam is uniformly mixed with waste phosphogypsum at a mass ratio of 1:4 to obtain foamed phosphogypsum; S3, an alkaline conditioner is added to the foamed phosphogypsum, and after uniform stirring, harmless phosphogypsum is obtained; S4, adding matured biomass to the harmless phosphogypsum, and after uniform stirring, organic phosphogypsum is obtained; S5, polyacrylamide is dissolved in water and then added to the organic phosphogypsum, and after uniform mixing, a mixture is obtained, and the moisture content of the mixture is 30%-35%; S6, the mixture is transferred to a granulator for granulation to obtain a porous solid waste plant growth substrate.

2. The method of claim 1, wherein the porous solid waste phytogenic substrate is prepared by the steps of: The particle size distribution of the porous solid waste plant growth substrate is: The mass percentage between 0.074 mm and d<0.5 mm is 10%; The mass percentage between 0.5 mm and d<1.0 mm is 20%; The mass percentage between 1.0 mm and d<2.0 mm is 50%; The mass percentage between 2.0 mm and d≤5.0 mm is 20%; Wherein, d is the particle size of the porous solid waste plant growth substrate.

3. The method of claim 1, wherein the porous solid waste phytogenic substrate is prepared by the steps of: In step S1, the concentration of the solution is 300-700 mg / L; the volume of the foam is 3-5 times the volume of the solution; the anionic surfactant includes at least one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and fatty alcohol polyoxyethylene ether sodium sulfate.

4. The method of claim 1, wherein the porous solid waste phytogenic substrate is prepared by the steps of: The addition amount of the alkaline conditioner is 0.5% of the mass of the foamed phosphogypsum; the alkaline conditioner includes at least one of quicklime, carbide slag and steel slag.

5. The method of claim 1, wherein the porous solid waste phytogenic substrate is prepared by the steps of: The addition amount of the matured biomass is 3%-5% of the mass of the foamed phosphogypsum; the matured biomass includes at least one of matured pine needles, matured rice husk and matured straw.

6. The method of claim 1, wherein the porous solid waste phytogenic substrate is prepared by the steps of: The addition amount of the polyacrylamide is 0.05% of the mass of the waste phosphogypsum.

7. A porous solid waste phytogenic substrate, characterized in that, The porous solid waste plant growth substrate is made by the preparation method of the porous solid waste plant growth substrate according to any one of claims 1-6.

8. Application of a porous solid waste phytogenic substrate in ecological restoration, characterized in that, The application comprises the following steps: Laying a plant growth layer with a height of 50 cm on the land to be repaired, the plant growth layer being the porous solid waste plant growth substrate according to claim 7; The compound fertilizer is uniformly spread on the vegetation layer in an amount of 30-50 g / m 2 and is subjected to a first ploughing operation to a depth of 5-10 cm, the compound fertilizer containing nitrogen, potassium and organic matter. The plant grass seeds are evenly spread on the vegetation layer after the first ploughing at a sowing amount of 150 g / m 2 The plant grass seeds are evenly spread on the vegetation layer after the first ploughing at a sowing amount of 150 g / m The complex microbial agent solution was sprayed on the vegetation layer after the second ploughing at a spraying amount of 1 L / m 2 The complex microbial agent solution was sprayed on the vegetation layer after the second ploughing at a spraying amount of 1 L / m After spraying, maintaining the land to complete the vegetation ecological restoration of the land to be repaired.

9. An integrated system for in-situ ecological remediation of porous solid waste phytogenic substrates, characterized by, The system comprises: A walking module comprising a walking part and a support platform, the support platform being installed on the walking part; A phosphogypsum collection and pretreatment module comprising a front scraper collector, a crushing and screening machine and a metering device, the front scraper collector being connected with the feeding port of the crushing and screening machine through a conveyor belt, and the discharging port of the crushing and screening machine being connected with the feeding port of the metering device; the front scraper collector is used for collecting waste phosphogypsum, and the front scraper collector and the crushing and screening machine are fixed on the support platform; The online mixing modification module comprises a surfactant foaming device, an alkaline conditioner adding bin, an organic matter adding bin, a binder adding bin and a double-shaft screw dynamic mixer; the surfactant foaming device comprises a solution configuration tank and a high-pressure foaming machine for foaming treatment of the solution in the solution configuration tank; the discharge port of the solution configuration tank is connected with the first section of the double-shaft screw dynamic mixer, and the discharge port of the metering device is connected with the inlet of the double-shaft screw dynamic mixer; the discharge port of the alkaline conditioner adding bin is connected with the second section of the double-shaft screw dynamic mixer; the discharge port of the organic matter adding bin is connected with the third section of the double-shaft screw dynamic mixer; the discharge port of the binder adding bin is connected with the fourth section of the double-shaft screw dynamic mixer; and the double-shaft screw dynamic mixer is fixed on the support platform; The granulation and spreading module comprises an angle-adjustable granulation disc, a substrate spreader and a seed-fertilizer-microbe compound spreading device; the inlet of the angle-adjustable granulation disc is connected with the outlet of the double-shaft screw dynamic mixer, the discharge port of the angle-adjustable granulation disc is connected with the substrate spreader, and the substrate spreader is used for laying a vegetation layer on the land to be repaired; the seed-fertilizer-microbe compound spreading device comprises a plurality of independent storage bins for storing grass seeds, compound fertilizers and microbial agents respectively, and each storage bin is provided with a meter for calculating the spreading amount; and the angle-adjustable granulation disc is fixed on the support platform. The intelligent control module is used for controlling the walking module, the phosphogypsum collection and pretreatment module, the online mixing modification module and the granulation and spreading module to realize continuous operation. The vegetation layer is the porous solid waste vegetation substrate according to claim 7, and the porous solid waste vegetation substrate is formed in the angle-adjustable granulation disc.

10. The integrated system for in-situ ecological remediation of porous solid waste phytogenic substrate according to claim 9, characterized in that, The system further comprises a front dust suppression spraying device and a rear dust suppression spraying device; the front dust suppression spraying device is fixed on the conveying belt; and the rear dust suppression spraying device is fixed on the support platform.

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