Planting substrate and preparation method and application thereof

Abstract

The invention relates to the technical field of solid waste resource utilization, and provides a planting matrix and a preparation method and application thereof.The planting matrix comprises solid waste and a water-based polymer material, the solid waste comprises secondary particles formed by a plurality of primary particles, and at least part of the water-based polymer material is combined to the outer surfaces of the primary particles; and the plurality of primary particles are connected with one another through a water-based polymer material to form secondary particles. According to the planting substrate provided by the invention, the solid wastes are combined with the water-based polymer material, so that the accumulation of the solid wastes and the environmental pollution can be reduced, the solid wastes can be converted into valuable resources, the resource utilization of the wastes is realized, and the resource utilization rate is relatively high.

Description

Technical Field

[0001] This application belongs to the field of solid waste resource utilization technology, and in particular relates to a planting substrate, its preparation method and application. Background Technology

[0002] my country's industrial production activities generate hundreds of millions of tons of industrial solid waste annually, such as fly ash and slag from coal-fired power generation, coal gangue from coal mining, and red mud from aluminum smelting. If these industrial solid wastes are not properly treated and are simply landfilled, they will not only occupy vast amounts of land resources but also cause serious environmental pollution, threatening ecological balance and human health. Therefore, the recycling and utilization of industrial solid waste is of paramount importance.

[0003] Currently, composting is a common resource recovery technology for the treatment and utilization of industrial solid waste. This technology involves adding microbial agents and other materials to industrial solid waste to create a suitable planting substrate, thus achieving high-value utilization of the waste. However, traditional composting technologies have some limitations. For example, the composting process is time-consuming, typically taking several months to complete, resulting in high time costs. Furthermore, the long composting cycle leads to relatively low production efficiency, which is not conducive to large-scale industrial production. In addition, energy consumption and cost control during large-scale production are also significant challenges.

[0004] Therefore, developing an industrial solid waste treatment technology that can improve the efficiency of industrial solid waste resource utilization, shorten processing time, reduce production costs, and is environmentally friendly has important practical significance and social value. Summary of the Invention

[0005] The purpose of this application is to provide a planting substrate, its preparation method and application, in order to solve the problems of low resource utilization rate and high cost of solid waste.

[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0007] In a first aspect, this application provides a planting substrate, comprising:

[0008] Solid waste, including secondary particles formed from multiple primary particles;

[0009] A water-based polymer material is at least partially bonded to the outer surface of the primary particles, and a plurality of the primary particles are connected to each other through the water-based polymer material to form secondary particles.

[0010] Secondly, this application provides a method for preparing a planting substrate, comprising the following steps:

[0011] Solid waste and water-based polymer materials are added to water and mixed to obtain a slurry.

[0012] The slurry is dried to obtain a planting substrate.

[0013] Thirdly, this application provides an application of a planting substrate in the fields of agriculture or horticulture.

[0014] The planting substrate provided in the first aspect of this application incorporates a water-based polymer material to bond primary particles of solid waste, allowing these particles to connect and form secondary particles. On one hand, the water-based polymer material provides support, increasing the gaps between the primary solid waste particles and resulting in a more porous structure with larger pores in the secondary particles. Furthermore, the water-based polymer material acts as a binder, making the structure of the secondary particles more stable. This results in a stable, large-pore structure in the secondary particles, which facilitates air circulation and water penetration, significantly improving the permeability and aeration of the planting substrate to meet the needs of plant root growth. On the other hand, the water-based polymer material has high hydrophilicity. When bonded to the outer surface of the primary solid waste particles, it effectively improves the water absorption and retention of the solid waste, giving the planting substrate good water stability and high water retention capacity. Due to the good water absorption of the planting substrate, its water content is increased, which helps maintain the distance between the planting substrate particles and prevents the particles from clumping together due to insufficient water content, thus preventing the planting substrate from hardening and compacting.

[0015] Therefore, by combining solid waste with water-based polymer materials, this application can not only reduce the accumulation of solid waste and environmental pollution, but also transform it into valuable resources, realizing the resource utilization of waste with a high resource utilization rate.

[0016] The second aspect of this application provides a method for preparing a planting substrate by mixing the raw material components contained in the planting substrate of this application, so that the water-based polymer material is combined with the surface of the primary particles of solid waste, thereby effectively preparing a planting substrate with good water stability, high porosity, and excellent permeability and air permeability. In addition, the preparation method of the planting substrate of this application has simple, reliable and controllable process conditions, which can ensure that the prepared planting substrate has stable performance, high efficiency, low cost, and is suitable for industrial application and promotion.

[0017] The application of the planting substrate provided in the third aspect of this application in the fields of agriculture and horticulture is beneficial because the planting substrate of this application has good water stability, high porosity and excellent permeability and air permeability. It can be applied to the fields of agriculture and horticulture, and can meet the needs of plant roots to absorb water and breathe oxygen, thereby promoting the smooth growth of plants. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a planting substrate provided in an embodiment of this application;

[0020] Figure 2 This is a schematic diagram of another planting substrate provided in an embodiment of this application;

[0021] Figure 3 These are photographs of solid waste and planting substrate provided in the embodiments of this application;

[0022] Figure 4 This is a scanning electron microscope image of fly ash provided in Embodiment 1 of this application;

[0023] Figure 5 This is a scanning electron microscope image of the planting substrate provided in Embodiment 1 of this application.

[0024] The following are the labeling elements in the figure:

[0025] 10. Primary particles, 20. Secondary particles, 30. Waterborne polymer materials. Detailed Implementation

[0026] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0028] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0029] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0030] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0031] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0032] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0033] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0034] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0035] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0036] The term "aqueous polymeric material" refers to polymeric materials that can be dispersed or dissolved in water, and these polymeric materials can be dispersed in water by physical or chemical methods to form stable emulsions or solutions.

[0037] The first aspect of this application provides a planting substrate, including:

[0038] Solid waste, including secondary particles formed from multiple primary particles;

[0039] A water-based polymer material is at least partially bonded to the outer surface of primary particles, and multiple primary particles are connected to each other through the water-based polymer material to form secondary particles.

[0040] As an example, please see Figure 1 The planting substrate includes solid waste and aqueous polymer material 30. The solid waste includes a plurality of secondary particles 20, which are formed by the aggregation of a plurality of primary particles 10. At least a portion of the aqueous polymer material 30 is bonded to the outer surface of the primary particles 10, and the plurality of primary particles 10 are connected by the aqueous polymer material 30 to form secondary particles 20.

[0041] As an example, please see Figure 2 The planting substrate includes solid waste and aqueous polymer material 30. The solid waste includes a plurality of secondary particles 20, which are formed by the aggregation of a plurality of primary particles 10. At least a portion of the aqueous polymer material 30 is bonded to the outer surface of the primary particles 10, and the plurality of primary particles 10 are connected by the aqueous polymer material 30 to form secondary particles 20.

[0042] This application does not limit the form of secondary particles composed of multiple primary particles connected by an aqueous polymer material. As an example, the aqueous polymer material can be located between two adjacent primary particles, and where the polymer has adhesive properties, the adjacent primary particles are connected by the aqueous polymer material. As an example, the aqueous polymer material is simultaneously connected to the surface of at least two primary particles, and since the aqueous polymer material is a continuous phase, at least two primary particles are connected by the aqueous polymer material. As an example, primary particles can first be combined with the aqueous polymer material to form composite particles, and then multiple composite particles can form secondary particles. In this way, the aqueous polymer material separates at least a portion of the gaps between adjacent primary particles, thereby allowing the primary particles to form independent particles; and at least some of the primary particles do not have direct contact but achieve indirect contact through the aqueous polymer material.

[0043] This application embodiment utilizes an embedded aqueous polymer material to bond primary solid waste particles, allowing these particles to connect and form secondary particles. On one hand, the aqueous polymer material provides support, increasing the gaps between the primary solid waste particles and resulting in a more porous structure with larger pores in the secondary particles. Furthermore, the aqueous polymer material has a binding effect, making the structure of the secondary particles more stable. This results in a stable, large-pore structure in the secondary particles, which facilitates air circulation and water penetration, significantly improving the permeability and aeration of the planting substrate and meeting the needs of plant root growth. On the other hand, the aqueous polymer material has high hydrophilicity. When bonded to the outer surface of the primary solid waste particles, it effectively improves the water absorption and retention of the solid waste, giving the planting substrate good water stability and high water retention capacity, preventing it from easily dispersing in water. The good water absorption of the planting substrate increases its water content, helping to maintain the distance between the particles and preventing the particles from clumping together due to insufficient water content, thus preventing the planting substrate from hardening and compacting.

[0044] In addition, water-based polymer materials have high safety, low environmental impact, are not easily absorbed and accumulated by vegetation, and degrade slowly, effectively extending their effective duration. Therefore, they are more conducive to the industrial promotion and application of planting substrates.

[0045] In the technical solution of this application, solid waste contains a variety of organic matter and minerals, which can serve as a nutrient provider. The water-based polymer material is not affected by the positive or negative charge of the solid waste and has multiple action sites, thus significantly improving adhesion performance. This allows for more effective bonding of primary particles of solid waste, enabling these particles to be connected by the water-based polymer material to form secondary particles. This results in a planting substrate with good water stability, high porosity, and excellent permeability and aeration. This not only reduces the accumulation of solid waste and environmental pollution but also transforms it into valuable resources, achieving resource utilization of waste with a high utilization rate.

[0046] In some embodiments, the aqueous polymer material is linked to the primary particles via hydrogen bonds.

[0047] Waterborne polymer materials contain abundant polar groups, such as hydroxyl (-OH), carboxyl (-COOH), and amino (-NH2). These polar groups can form hydrogen bonds with substances in solid waste, such as inorganic minerals. As a result, a strong binding force is formed between the waterborne polymer material and the primary particles of solid waste. This not only facilitates the connection of multiple primary particles through the waterborne polymer material to form secondary particles and obtain planting substrates with suitable sizes, but also helps to improve the stability of the planting substrate.

[0048] As an example, the inorganic minerals contained in solid waste include, but are not limited to, at least one of quartz, mullite, and potassium feldspar.

[0049] In some embodiments, a particle gap is formed between adjacent primary particles.

[0050] Interparticle gaps can form between primary particles, and there are many reasons for the formation of these gaps. For example, primary particles may have different particle sizes. When primary particles of different sizes are stacked, gaps that other particles cannot fill will be created. Another example is that the surface of primary particles may be bonded with water-based polymer materials, which prevents the primary particles from making direct contact when they are stacked, thus forming gaps.

[0051] The presence of gaps between particles creates a porous structure in the planting substrate, including secondary particles. This facilitates air circulation and water penetration, effectively improving the aeration and permeability of the planting substrate.

[0052] In some embodiments, solid waste includes at least one of fly ash, coal gangue, red mud, slag, and silt.

[0053] These solid wastes mainly originate from industrial production and energy utilization processes. They are widely available, relatively inexpensive to obtain, and contain abundant nutrients such as nitrogen, phosphorus, potassium, calcium, magnesium, iron, and zinc. Therefore, these solid wastes can serve as nutrient providers for plant growth. For example, fly ash contains high levels of silicon, calcium, and magnesium; coal gangue contains nitrogen, phosphorus, and potassium; red mud is rich in iron, aluminum, and calcium; slag contains significant amounts of silicon, calcium, and magnesium; and silt contains abundant organic matter and nutrients.

[0054] In some embodiments, the waterborne polymer material includes at least one of waterborne polyurethane, waterborne ethylene-vinyl acetate copolymer, styrene-butadiene rubber, polyvinyl alcohol, polyacrylic acid, and polyacrylamide.

[0055] These water-based polymer materials have a certain degree of adhesion, which is conducive to their bonding with primary solid waste particles, allowing multiple primary solid waste particles to be connected through the water-based polymer materials; moreover, these water-based polymer materials have high hydrophilicity, which is beneficial to improving the water retention and water absorption of the planting substrate.

[0056] Solid waste tends to form a viscous paste when wet and hardens and compacts when dry, resulting in low permeability and air permeability, making it unsuitable for direct use as a planting substrate. Therefore, this application incorporates an aqueous polymer material onto the surface of primary solid waste particles, connecting multiple primary particles to form secondary particles. The presence of the aqueous polymer material gives the secondary particles a stable, large-pore structure, which facilitates air circulation and water penetration. This significantly improves the permeability and air permeability of the planting substrate, promoting plant root growth. Furthermore, the aqueous polymer material has high hydrophilicity, giving the planting substrate good water stability and high water retention capacity. The good water absorption of the planting substrate increases its moisture content, helping to maintain the distance between particles and preventing dense particle packing due to insufficient moisture content, thus preventing hardening and compaction.

[0057] In some embodiments, the mass ratio of solid waste to aqueous polymer material is 100:0.1-10. Exemplary examples include typical but non-limiting values ​​such as 100:0.1, 100:0.5, 100:1, 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8, 100:9, and 100:10.

[0058] By controlling the mass ratio of solid waste to water-based polymer materials within the above range, sufficient water-based polymer materials can exert their binding properties to connect multiple primary solid waste particles together to form secondary particles.

[0059] In some embodiments, the particle size of the solid waste is 0.1 μm-1000 μm. Exemplary examples include typical but non-limiting values ​​such as 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 30 μm, 50 μm, 80 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, and 1000 μm.

[0060] Controlling the particle size of solid waste within the above-mentioned range is beneficial for the combination of water-based polymer materials and solid waste. This allows multiple solid waste particles to be connected together in one step by the water-based polymer materials, forming a planting substrate with good porosity and water retention capacity.

[0061] In some embodiments, the particle size of the planting substrate is 0.01mm-30mm. For example, the particle size of the planting substrate can be typical but not limiting values ​​such as 0.01mm, 0.1mm, 0.5mm, 1mm, 5mm, 10mm, 15mm, 20mm, 25mm, and 30mm.

[0062] Controlling the particle size of the planting substrate within the above-mentioned range helps to improve its porosity, permeability, and air permeability.

[0063] In some embodiments, the particle size of the planting substrate is 0.05 mm to 2 mm. For example, the particle size of the planting substrate can be typical but not limiting values ​​such as 0.05 mm, 0.1 mm, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, and 2 mm.

[0064] Multiple primary solid waste particles are bonded together with an aqueous polymer material to form secondary particles, thereby obtaining a planting substrate. Therefore, controlling the particle size of the planting substrate within the above range means that the secondary particles have a high porosity, thus giving the planting substrate high permeability and air permeability.

[0065] In some embodiments, the porosity of the planting substrate is 40%-85%. Exemplary examples include typical but non-limiting values ​​such as 40%, 50%, 60%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, and 85%.

[0066] The porosity of a planting substrate refers to the ratio of the volume of pores to the total volume of the substrate, usually expressed as a percentage, and can be obtained using the following formula (I):

[0067]

[0068] In formula (I), particle density refers to the mass per unit volume of particles in the planting substrate; bulk density refers to the weight of a certain substance per unit volume. For planting substrates, bulk density refers to the weight of a unit volume of planting substrate (including planting substrate pores) under natural conditions.

[0069] The porosity of the planting substrate in this application originates from two sources. Firstly, it is generated when the primary particles of solid waste are piled up. Since the outer surface of the primary particles is bonded with water-based polymer materials, large gaps are formed between the primary particles. Secondly, the particles of the planting substrate can also generate interparticle gaps when piled up.

[0070] Controlling the porosity of the planting substrate within the aforementioned range has several advantages. First, the pores in the planting substrate can serve as channels for air circulation and storage space for water, thereby significantly improving the permeability and aeration of the planting substrate and meeting the needs of plant root growth. Second, it means that the bulk density of the planting substrate is lower, making it looser and more conducive to the extension of plant roots.

[0071] In some embodiments, the saturated water content of the planting substrate is 40%-80%. Exemplary examples show that the saturated water content of the planting substrate can be typical but not limiting values ​​such as 40%, 50%, 60%, 70%, and 80%.

[0072] Saturated water content refers to the maximum amount of water that a planting substrate can hold under specific temperature and pressure conditions, at which point the substance is in a water-saturated state. In this application, the saturated water content of the planting substrate refers to the maximum amount of water that the planting substrate can hold under normal temperature and pressure.

[0073] Controlling the saturated water content of the planting substrate within the above-mentioned range means, on the one hand, that the planting substrate can store more water, thereby promoting plant growth and development; on the other hand, it indicates that the planting substrate has good water retention and air permeability, which can reduce compaction and have a positive impact on promoting plant root growth and the survival and reproduction of microorganisms.

[0074] In some embodiments, the saturated hydraulic conductivity of the planting substrate is 0.0001-0.01 cm / s. Exemplary examples include typical but non-limiting values ​​such as 0.0001 cm / s, 0.0005 cm / s, 0.001 cm / s, 0.002 cm / s, 0.005 cm / s, 0.008 cm / s, and 0.01 cm / s.

[0075] Saturated hydraulic conductivity refers to the flow rate of water through a unit area per unit time when the planting substrate is fully saturated, and is used to reflect the rate of water penetration in a saturated medium.

[0076] Controlling the saturated hydraulic conductivity of the planting substrate within the above range means that water can pass through the planting substrate quickly and is less likely to accumulate, which helps the plant roots breathe and grow.

[0077] In some embodiments, the bulk density of the planting substrate is 0.5-1 g / cm³. 3 For example, the bulk density of the planting substrate can be 0.5 g / cm³. 3 0.55g / cm 3 0.6g / cm 3 0.65g / cm 3 0.7g / cm 3 0.75g / cm 3 0.8g / cm 3 0.85g / cm 3 0.9g / cm 3 0.95g / cm 3 1g / cm 3 Typical but not restrictive values.

[0078] Bulk density, also known as density, refers to the weight of a unit volume of a substance. For planting substrates, bulk density refers to the weight of a unit volume of planting substrate (including the pores of the planting substrate) under natural conditions.

[0079] By controlling the bulk density of the planting substrate within the above-mentioned range, the planting substrate contains larger pores and has a loose overall structure, which is conducive to the circulation of water and air, thereby promoting the growth and extension of plant roots.

[0080] The second aspect of this application provides a method for preparing a planting substrate, comprising the following steps:

[0081] Step S10: Add solid waste and water-based polymer materials to water, mix and process to obtain slurry;

[0082] Step S20: Dry the slurry to obtain the planting substrate.

[0083] The second aspect of the embodiments of this application provides a method for preparing a planting substrate. This method involves mixing the raw material components of the planting substrate according to the method described above, so that the aqueous polymer material binds to the surface of the primary solid waste particles. This effectively prepares a planting substrate with good water stability, high porosity, and excellent permeability and air permeability. Furthermore, the preparation method of the planting substrate in this application has simple, reliable, and controllable process conditions, ensuring stable performance, high efficiency, low cost, and suitability for industrial application and promotion.

[0084] In some embodiments, the selection of solid waste in step S10 is as described above and will not be repeated here.

[0085] In some embodiments, the selection of the aqueous polymer material in step S10 is as described above and will not be repeated here.

[0086] In some embodiments, in step S10, the aqueous polymer material is added in the form of an aqueous polymer emulsion or an aqueous polymer solution, wherein the solid content of the aqueous polymer emulsion is 10%-50% and the solid content of the aqueous polymer solution is 1%-15%.

[0087] Solid content refers to the percentage of the mass of solid components in a substance under certain conditions. In this application, solid content refers to the content of aqueous polymer materials in aqueous polymer emulsions or aqueous polymer solutions.

[0088] Using water as the dispersion medium, aqueous polymer emulsions or solutions have good compatibility with water, can be rapidly dispersed in water to form a stable system, and can more easily mix with solid waste in water.

[0089] In some embodiments, based on the total weight of the slurry (100%), the amount of solid waste added is 50%-80%, the amount of waterborne polymer material added is 1%-25%, and the amount of water added is 5%-50%.

[0090] For example, the amount of solid waste added can be typical but not limiting values ​​such as 50%, 55%, 60%, 65%, 70%, 75%, 80%.

[0091] For example, the amount of aqueous polymer material added can be typical but not limiting values ​​such as 1%, 5%, 10%, 20%, 25%.

[0092] For example, the amount of water added can be typical but not limiting values ​​such as 5%, 10%, 20%, 30%, 40%, 50%.

[0093] In some embodiments, the amount of aqueous polymer material added is 1%-10% based on 100% of the total weight of the slurry. Exemplary examples include typical but non-limiting values ​​such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%.

[0094] Controlling the amount of water-based polymer material added within the above range not only allows solid waste to be connected by the water-based polymer material to form secondary particles, but also helps to improve the water retention of the planting substrate.

[0095] In some embodiments, the amount of water added is 15%-25% of the total weight of the slurry. Exemplary examples include typical but non-limiting values ​​such as 15%, 18%, 20%, 22%, and 25%.

[0096] Controlling the amount of water added within the above range helps to mix solid waste and water-based polymer materials evenly, thereby allowing the solid waste particles to be connected through the water-based polymer materials to obtain the planting substrate.

[0097] In some embodiments, the mixing conditions include stirring at 20 rpm to 100 rpm for 10 min to 200 min. For example, the stirring speed can be typical but not limiting values ​​such as 20 rpm, 30 rpm, 40 rpm, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, and 100 rpm, and the stirring time can be typical but not limiting values ​​such as 10 min, 20 min, 50 min, 80 min, 100 min, 120 min, 150 min, 180 min, and 200 min.

[0098] Under the above-mentioned mixing conditions, solid waste and water-based polymer materials can be mixed evenly in water, thereby increasing the contact effect between solid waste and water-based polymer materials.

[0099] In some embodiments, the drying conditions include: heat treatment at 35°C-60°C for 6h-24h, followed by heat treatment at 90°C-120°C for 0.5h-12h.

[0100] The drying process consists of two stages. The first stage involves heat treatment at 35℃-60℃ for 6-24 hours, and the second stage involves heat treatment at 90℃-120℃ for 0.5-12 hours. During the drying process, the contact distance between the solid waste and the aqueous polymer material gradually decreases, which increases the contact area between the aqueous polymer material and the solid waste. This provides favorable conditions for the formation of hydrogen bonds between the aqueous polymer material and the solid waste, strengthens the binding ability of the aqueous polymer material with the inorganic minerals in the solid waste, and, due to the improved binding ability, enables the aqueous polymer material to connect multiple solid waste particles to form a planting substrate with specific particle size characteristics.

[0101] In particular, the second stage of the drying process allows some of the water-based polymer materials to crystallize, resulting in a more ordered molecular arrangement. This not only makes it easier for the water-based polymer materials to retain moisture in the planting substrate, reducing water evaporation and increasing the water retention of the planting substrate, but also makes the pore size within the planting substrate more uniform, thereby increasing its air permeability and water permeability, which is more conducive to root growth and respiration.

[0102] Please see Figure 3 , Figure 3 -A shows photos of solid waste. Figure 3 -B shows a photo of the planting substrate, from Figure 3 It is evident from the above that the planting substrate prepared in this embodiment has large gaps between the particles, and the particles are loose, which is more conducive to plant growth.

[0103] In some embodiments, after drying the slurry, a screening step is further included, as follows:

[0104] The dried granules are screened to obtain a planting substrate with a particle size of 0.01mm-30mm.

[0105] The third aspect of this application provides an application of a planting substrate in the fields of agriculture and horticulture.

[0106] Since the planting substrate in the first aspect of this application and / or the planting substrate prepared by the method in the second aspect have good water stability, high porosity and excellent permeability and air permeability, they can be applied to agriculture or horticulture and other fields, and can meet the needs of plant roots to absorb water and breathe oxygen, thereby promoting the smooth growth of plants.

[0107] The following description is based on specific embodiments.

[0108] Example 1

[0109] This embodiment provides a planting substrate and its preparation method.

[0110] A planting substrate includes solid waste (fly ash, particle size 1-30 μm) and water-based polymer material (anionic water-based polyurethane) in a mass ratio of 100:3. The solid waste includes secondary particles composed of multiple primary particles, at least a portion of the water-based polymer material is bonded to the outer surface of the primary particles, and the multiple primary particles are connected by the water-based polymer material to form secondary particles.

[0111] A method for preparing a planting substrate includes the following steps:

[0112] Step S1: Add 100kg of solid waste and 10kg of aqueous polymerization solution with a solid content of 30% to 50kg of water and mix. Then use a cement mixer to stir at 50rpm for 10min to obtain slurry.

[0113] Step S2: Treat the slurry at 40℃ for 10 hours, and then at 100℃ for 5 hours to obtain dry material;

[0114] Step S3: Pass the dry material through a 1mm sieve to obtain the planting substrate.

[0115] Example 2

[0116] This embodiment provides a planting substrate and its preparation method.

[0117] A planting substrate includes solid waste (red mud, with a particle size of 60 μm) and water-based polymeric material (polyvinyl alcohol) in a mass ratio of 100:0.5. The solid waste includes secondary particles composed of multiple primary particles, at least a portion of which is bonded to the outer surface of the primary particles, and the multiple primary particles are connected by the water-based polymeric material to form secondary particles.

[0118] A method for preparing a planting substrate includes the following steps:

[0119] Step S1: Add 100kg of solid waste and 5kg of aqueous polymer solution with a solid content of 10% to 30kg of water and mix. Then use a cement mixer to stir at 30rpm for 30min to obtain slurry.

[0120] Step S2: Treat the slurry at 50℃ for 15 hours, and then at 110℃ for 6 hours to obtain dry material;

[0121] Step S3: Pass the dry material through a 3mm sieve to obtain the planting substrate.

[0122] Example 3

[0123] This embodiment provides a planting substrate and its preparation method.

[0124] A planting substrate includes solid waste (coal gangue powder, particle size 74 μm) in a mass ratio of 100:1.8 and water-based polymeric material (polyacrylic acid and styrene-butadiene rubber in a mass ratio of 1:8), wherein the solid waste includes secondary particles composed of multiple primary particles, at least a portion of the water-based polymeric material is bonded to the outer surface of the primary particles, and the multiple primary particles are connected by the water-based polymeric material to form secondary particles.

[0125] A method for preparing a planting substrate includes the following steps:

[0126] Step S1: Add 100kg of solid waste, 1kg of polyacrylic acid solution with a solid content of 20%, and 8kg of styrene-butadiene rubber latex with a solid content of 20% to 50kg of water and mix. Then use a cement mixer to stir at 40rpm for 15min to obtain slurry.

[0127] Step S2: Treat the slurry at 30℃ for 20 hours, and then at 120℃ for 1 hour to obtain dry material;

[0128] Step S3: Pass the dry material through a 0.5mm sieve to obtain the planting substrate.

[0129] Example 4

[0130] This embodiment provides a planting substrate and its preparation method.

[0131] A planting substrate, which differs from Example 1 in that the ratio of solid waste to water-based polymeric material is 100:0.1, while the rest is the same as in Example 1.

[0132] Example 5

[0133] This embodiment provides a planting substrate and its preparation method.

[0134] A planting substrate, which differs from Example 1 in that the ratio of solid waste to water-based polymeric material is 100:1, otherwise it is the same as Example 1.

[0135] Example 6

[0136] This embodiment provides a planting substrate and its preparation method.

[0137] A planting substrate, which differs from Example 1 in that the ratio of solid waste to water-based polymeric material is 100:10, otherwise it is the same as Example 1.

[0138] Example 7

[0139] This embodiment provides a planting substrate and its preparation method.

[0140] A planting substrate, which differs from Example 1 in that the particle size of the planting substrate is different.

[0141] A method for preparing a planting substrate, which differs from Example 1 in that the sieve in step S3 has a size of 5 mm.

[0142] Example 8

[0143] This embodiment provides a planting substrate and its preparation method.

[0144] A planting substrate, which differs from Example 1 in that the particle size of the planting substrate is different.

[0145] A method for preparing a planting substrate, which differs from Example 1 in that the sieve in step S3 has a size of 10 mm.

[0146] Example 9

[0147] This embodiment provides a planting substrate and its preparation method.

[0148] A planting substrate, which differs from Example 1 in that the particle size of the planting substrate is different.

[0149] A method for preparing a planting substrate, which differs from Example 1 in that the sieve in step S3 has a size of 30 mm.

[0150] Comparative Example 1

[0151] This comparative example provides a planting substrate consisting only of fly ash.

[0152] Comparative Example 2

[0153] This comparative example provides a planting substrate consisting only of red mud.

[0154] Performance testing

[0155] (1) Morphological test

[0156] The fly ash and planting substrate provided in Example 1 were analyzed by scanning electron microscopy (SEM). The SEM image of the fly ash is shown below. Figure 4 As shown, the scanning electron microscope image of the planting substrate is as follows: Figure 5 As shown.

[0157] from Figure 4 It can be clearly observed that the primary fly ash particles are spherical or near-spherical, and there is no obvious aggregation between adjacent particles.

[0158] from Figure 5 It is evident that multiple primary particles are tightly packed together to form secondary particles, and the bonding between the particles is quite strong.

[0159] (2) Performance Testing

[0160] The planting substrates provided in Examples 1-9 and Comparative Examples 1-2 were subjected to performance tests, and the results are shown in Table 1 below.

[0161] Table 1

[0162] Item Container weight (g / cm 3 ) Porosity (%) Saturation water content (%) Example 1 0.8 70 70 Example 2 0.6 80 78 Example 3 0.74 72 74 Example 4 0.82 69 67 Example 5 0.77 71 73 Example 6 0.74 72 75 Example 7 0.62 77 62 Example 8 0.55 79 52 Example 9 0.48 82 42 Comparative Example 1 1.5 44 30 Comparative Example 2 1.6 38 36

[0163] in:

[0164] The method for testing bulk density is as follows:

[0165] Fill a 1L cylindrical container with dry planting substrate, then weigh the substrate in the cylindrical container. Here, mass refers to the mass of the planting substrate in the cylindrical container, and volume refers to the volume of the cylindrical container.

[0166] Porosity can be calculated using formula (I):

[0167]

[0168] The particle density was tested using the specific gravity bottle method, which involved placing the dry planting substrate into the specific gravity bottle; then adding enough water to completely submerge the planting substrate, with the water level reaching the marked line on the specific gravity bottle; finally, sealing the specific gravity bottle to ensure there were no air bubbles.

[0169]

[0170] In formula (II):

[0171] m s This refers to the mass of the planting substrate, measured in grams (g).

[0172] m1 refers to the sum of the mass of water and the specific gravity bottle, expressed in grams (g).

[0173] m2 refers to the sum of the mass of the planting substrate, water, and specific gravity bottle, expressed in grams (g).

[0174] G wt This refers to the specific gravity of distilled water at t℃.

[0175] The test method for saturated water content is as follows:

[0176] A certain amount of planting substrate is weighed out, and its mass in the dry state is recorded as m. a Its mass in the water-saturated state is denoted as m. b ,but:

[0177]

[0178] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A growing substrate, characterized in that, The solid waste comprises at least one of fly ash, coal gangue, red mud, slag and silt; and / or The water-based polymer material comprises at least one of water-based polyurethane, water-based ethylene-vinyl acetate copolymer, styrene-butadiene rubber, polyvinyl alcohol, polyacrylic acid and polyacrylamide. The mass ratio of the solid waste to the water-based polymer material is 100:0.1-10; and / or 2. The growing medium of claim 1, wherein, The particle size of the solid waste is 0.1 μm-1000 μm.

3. The growing medium of claim 1, wherein, The planting substrate satisfies at least one of the following characteristics (1)-(5):

4. The growing medium of claim 1, wherein, (1) The particle size of the planting substrate is 0.01 mm-30 mm; (2) The porosity of the planting substrate is 40%-85%; 5. The growing medium of claim 1, wherein, (3) The saturated water content of the planting substrate is 40%-80%; (4) The saturated hydraulic conductivity of the planting substrate is 0.0001-0.01 cm / s; 6. The growing medium of any one of claims 1 to 5, wherein, The method comprises the following steps: adding the solid waste and the water-based polymer material into water, mixing and treating to obtain a slurry; drying the slurry to obtain the planting substrate. The water-based polymer material is added in the form of water-based polymer emulsion or water-based polymer solution, the solid content of the water-based polymer emulsion is 10%-50%, and the solid content of the water-based polymer solution is 1%-15%; and / or The adding amount of the solid waste is 50%-80%, the adding amount of the water-based polymer material is 1%-25%, and the adding amount of water is 5%-50%, based on the total weight of the slurry being 100%. (5) the bulk density of the planting substrate is 0.5-1 g / cm 3 .

7. A method of preparing a growing substrate, characterized by, The mixing and treating conditions comprise stirring at 20 rpm-100 rpm for 10 min-200 min; and / or The drying conditions comprise heat treating at 35°C-60°C for 6 h-24 h, and then heat treating at 90°C-120°C for 0.5 h-12 h.

10. The application of the planting substrate of any one of claims 1-6 and / or the planting substrate prepared by the method of any one of claims 7-9 in the field of agriculture or horticulture.

8. The method for producing a planting medium according to claim 7, characterized by, ​ ​ 9. The method for preparing a planting medium according to claim 7, wherein ​ ​ ​

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