Fly ash-based matrix soil and preparation method and application thereof

Abstract

The application provides a fly ash-based substrate soil and a preparation method and application thereof, and belongs to the technical field of waste utilization and improved fly ash soil. The fly ash-based substrate soil takes fly ash and slag as main raw materials, and by adding organic peat soil, coconut shell activated carbon, coconut chaff, diatomite, biological organic fertilizer, vermiculite, rotten sugar cane straw, coconut shell, photosensitive organic carbon, SiC and graphene gel suspension fertilizer, the soil colloid particle structure of the fly ash as the substrate soil can be significantly improved. Meanwhile, the preparation method of the fly ash-based substrate soil promotes plant growth, does not cause the plant to enrich heavy metals, the content of heavy metals in the plant meets the requirement of the heavy metal limitation in the GB2762-2022 "National Food Safety Standard Limit of Pollutants in Food", and promotes the healthy growth of the plant. In addition, the fly ash-based substrate soil can be used as soil for greening and forest land.

Description

Technical Field

[0001] This invention belongs to the field of waste utilization and improved fly ash soil technology, and particularly relates to a fly ash-based matrix soil and its preparation method and application. Background Technology

[0002] Fly ash, as an industrial solid waste, has received considerable attention and research. Its generation and treatment are increasingly valued. Fly ash is the solid, fine particulate matter carried into the flue gas duct after coal combustion in the furnace, collected by dust removal equipment. Larger particles, or lumps, are discharged from the bottom of the furnace and are called bottom ash, or simply ash or large ash. Coal is a major energy source in the energy structure, and coal-fired power generation is one of the main ways to utilize coal. With the development of the power industry, the amount of fly ash emitted by coal-fired power plants is increasing year by year, as is the land area occupied by fly ash dumping. If large amounts of fly ash are not treated, they will generate dust, and the air pollution and environmental pollution caused by fly ash dust emissions are becoming increasingly serious. Therefore, the treatment of fly ash is urgent. How to turn fly ash into a valuable resource and utilize it rationally will not only promote the widespread adoption of green development concepts but also increase economic benefits, transforming fly ash from waste into a valuable resource.

[0003] Fly ash has specific physical properties, such as texture, water holding capacity, bulk density and pH value, and contains almost all essential nutrients for plants. It can be used to improve soil, improve soil physical and chemical properties, reduce crop pests and increase crop yield. Therefore, the application of fly ash in agricultural production can be considered. However, fly ash has the following main problems in various soil improvement and remediation: (1) Fly ash contains almost no clay particles, the particles are single particles, loose when dry and do not stick together when wet, making it difficult to form a granular structure. (2) The use of fly ash may lead to the accumulation of heavy metals in crops or cause crop poisoning. Excessive application may also cause heavy metal pollution of groundwater or soil surface. (3) Since fly ash contains almost no nitrogen and organic matter, the single application of fly ash cannot provide a balanced supply of soil nutrients. The combined adaptation of fly ash with other solid wastes can make up for the shortcomings of single application, but the type, ratio and combined use of solid waste will affect the improvement effect.

[0004] Therefore, there is still a need to design a fly ash-based matrix soil and its preparation method, which can reduce environmental pollution caused by fly ash, increase the planting of green crops, and increase economic benefits to a certain extent. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a fly ash-based matrix soil, its preparation method and application. The fly ash-based matrix soil has excellent soil colloidal aggregate structure, which can promote plant growth and will not cause plants to accumulate heavy metals.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a fly ash-based matrix soil, comprising the following components: Fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC and graphene gel suspension fertilizer dilution; The mass-to-volume ratio of the diluted fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC, and graphene gel suspension fertilizer is (4~8) kg: (1~4) kg: (1~4) kg: (0.5~2.5) kg: (0.5~2.5) kg: (0.1~1.2) kg: (0.5~1.5) kg: (0.1~0.6) kg: (1~2.5) kg: (0.05~0.15) kg: (0.05~0.6) kg: (0.1~0.6) kg: (500~5000) mL.

[0007] Preferably, the method for preparing the decomposed sugarcane straw includes the following steps: Sugarcane stalks were mixed with ammonium nitrate to obtain a mixture; The mixture is mixed with EM bacteria, water is added, and the mixture is stirred evenly to obtain a fermentation mixture. Fermentation is then carried out to obtain decomposed sugarcane straw.

[0008] Preferably, the diluent of the graphene gel suspension fertilizer is prepared by mixing water with the graphene gel suspension fertilizer.

[0009] More preferably, the volume ratio of water to graphene gel suspension fertilizer is 500~2000:1.

[0010] Preferably, the mass ratio of sugarcane straw to ammonium nitrate is 8-12:1; the mass ratio of the mixture to EM bacteria is 980-1000:10; the water content is such that the moisture content of the fermentation mixture is 55%-65%; during fermentation, the fermentation mixture is covered with polyethylene film, turned over once on the 7th-10th day of fermentation, and turned over again on the 11th-20th day of fermentation, for a total fermentation period of 25-35 days.

[0011] This invention provides a method for preparing the above-mentioned fly ash-based matrix soil, comprising the following steps: The fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon and SiC are mixed, crushed and sieved to obtain a mixture powder, granulated, and sprayed with a diluted solution of graphene gel suspension fertilizer during granulation to obtain fly ash-based matrix soil.

[0012] Preferably, the pulverized and sieved material has a mesh size of 40-60; during granulation, the tilt angle is 30°-35°, the rotation speed is 10-15 r / min, and the granulation time is 5-20 min.

[0013] Preferably, the diluent of the graphene gel suspension fertilizer is prepared by mixing water with the graphene gel suspension fertilizer.

[0014] Preferably, the volume ratio of water to graphene gel suspension fertilizer is 500~2000:1.

[0015] This invention provides the application of the above-mentioned fly ash-based matrix soil or the fly ash-based matrix soil prepared by the above-mentioned preparation method in promoting plant growth.

[0016] Preferably, the plant includes one or more of bahia grass, wheat, and alfalfa; the growth traits include germination rate and plant height.

[0017] This invention provides a method for promoting plant growth, comprising the following steps: The plant is planted in the fly ash-based matrix soil or the fly ash-based matrix soil prepared by the preparation method.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a fly ash-based matrix soil, its preparation method, and its applications. The fly ash-based matrix soil of this invention uses fly ash and slag as the main raw materials. By adding organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC, and graphene gel suspension fertilizer, the soil colloidal aggregate structure of fly ash-based matrix soil can be significantly improved. It can also improve the bulk density, organic matter, and ammonium nitrogen (N) retention of the fly ash-based matrix soil. Simultaneously, the fly ash-based matrix soil prepared by this invention promotes plant growth and does not lead to the accumulation of heavy metals in plants. The heavy metal content in plants meets the heavy metal limits required by GB2762-2022, "National Food Safety Standard: Limits of Contaminants in Food." Furthermore, the fly ash-based matrix soil of this invention can be used as soil for landscaping and forestry. Therefore, this invention increases environmental and economic benefits, turning fly ash waste into a valuable resource and realizing the resource utilization of waste. Detailed Implementation

[0019] This invention provides a fly ash-based matrix soil, comprising the following components: Fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC and graphene gel suspension fertilizer dilution; The mass-to-volume ratio of the diluted fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC, and graphene gel suspension fertilizer is (4~8) kg: (1~4) kg: (1~4) kg: (0.5~2.5) kg: (0.5~2.5) kg: (0.1~1.2) kg: (0.5~1.5) kg: (0.1~0.6) kg: (1~2.5) kg: (0.05~0.15) kg: (0.05~0.6) kg: (0.1~0.6) kg: (500~5000) mL.

[0020] In a preferred embodiment, the mass-to-volume ratio of the diluted fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC, and graphene gel suspension fertilizer is (5~7) kg: (2~3) kg: (2~3) kg: (1~2) kg: (1~2) kg: (0.2~1) kg: (0.9~1.1) kg: (0.2~0.5) kg: (1.5~2) kg: (0.07~0.12) kg: (0.1~0.5) kg: (0.2~0.5) kg: (1000~5000) mL. In a preferred embodiment, the fly ash-based matrix soil is made from the following components: fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC, and graphene gel suspension fertilizer dilution. The fly ash-based matrix soil of this invention uses fly ash and slag as the main raw materials. By adding fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC, and graphene gel suspension fertilizer dilution, the soil colloidal aggregate structure of the fly ash-based matrix soil is significantly improved. Simultaneously, the organic matter and ammonium nitrogen (N) retention of the fly ash-based matrix soil are increased, and the bulk density of the fly ash-based matrix soil is improved, making the fly ash-based matrix soil suitable for plant growth.

[0021] In this invention, the preferred method for preparing the decomposed sugarcane straw includes the following steps: mixing sugarcane straw with ammonium nitrate to obtain a mixture; The mixture is mixed with EM bacteria, water is added, and the mixture is stirred evenly to obtain a fermentation mixture. Fermentation is then carried out to obtain decomposed sugarcane straw.

[0022] In this invention, the diluted solution of the graphene gel suspension fertilizer is prepared by mixing water with the graphene gel suspension fertilizer. The volume ratio of water to graphene gel suspension fertilizer is preferably 500~2000:1, such as 500:1, 1000:1 or 2000:1.

[0023] In this invention, sugarcane straw is mixed with ammonium nitrate to obtain a mixture. The preferred mass ratio of sugarcane straw to ammonium nitrate is 8-12:1, more preferably 9-11:1, and even more preferably 10:1; the mass ratio of the mixture to EM bacteria is 980-1000:10, more preferably 985-995:10, such as 990:10; the added water content, resulting in a moisture content of the fermentation mixture, is preferably 55%-65%, more preferably 58%-62%, such as 60%; during fermentation, the fermentation mixture is covered with a polyethylene film, turned over once on days 7-10, and again on days 11-20, for a total fermentation period of 25-35 days. As a preferred embodiment, during fermentation, the fermentation mixture is covered with a polyethylene film, turned over once on day 9, and again on day 15, for a total fermentation period of 30 days. The thickness of the polyethylene film is 0.02 mm. This invention does not have a specific limitation on the source of the polyethylene film; commercially available products in the field are acceptable.

[0024] This invention provides a method for preparing the above-mentioned fly ash-based matrix soil, comprising the following steps: The fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon and SiC are mixed, crushed and sieved to obtain a mixture powder, granulated, and sprayed with a diluted solution of graphene gel suspension fertilizer during granulation to obtain fly ash-based matrix soil.

[0025] In this invention, fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, and SiC are mixed, pulverized, and sieved to obtain a mixed powder. The preferred mesh size for pulverization and sieving is 40-60 mesh, more preferably 45-55 mesh, and even more preferably 50 mesh. During granulation, the tilt angle is 30°-35°, the rotation speed is 10-15 r / min, and the granulation time is 5-20 min. As a preferred embodiment, the tilt angle is 33°, the rotation speed is 11 r / min, and the granulation time is 15 min.

[0026] In this invention, after obtaining the mixed powder, it is granulated. During granulation, a diluted solution of graphene gel suspension fertilizer is sprayed onto the soil to obtain fly ash-based matrix soil. The diluted solution of graphene gel suspension fertilizer is prepared by mixing water with graphene gel suspension fertilizer. The volume ratio of water to graphene gel suspension fertilizer is 500~2000:1, such as 500:1, 1000:1, or 2000:1.

[0027] The fly ash-based matrix soil obtained by the above granulation method has a particle size of 0.1~10mm.

[0028] This invention provides the application of the above-mentioned fly ash-based matrix soil or the fly ash-based matrix soil prepared by the above-mentioned preparation method in promoting plant growth.

[0029] In this invention, the plant includes one or more of bahia grass, wheat, and alfalfa; the growth traits include germination rate and plant height. The fly ash-based substrate soil of this invention can promote the germination rate of bahia grass and increase the plant height of wheat and / or alfalfa.

[0030] This invention provides a method for promoting plant growth, comprising the following steps: The plant is planted in the fly ash-based matrix soil or the fly ash-based matrix soil prepared by the preparation method.

[0031] In this invention, the plant includes one or more of bahia grass, wheat, and alfalfa. This invention does not impose any particular limitation on the planting method; planting methods well-known in the art or local planting practices can be used.

[0032] In this invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

[0033] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0034] In the following embodiments, the fly ash and slag are fly ash and slag produced by Baise Baikuang Power Generation Co., Ltd. The generated ash and slag are all produced by circulating fluidized bed combustion dry runoff.

[0035] The organic peat moss was purchased from Guangxi Landsol Technology Co., Ltd., and the coconut shell activated carbon was purchased from Guangdong Huayi Activated Carbon Co., Ltd. Diatomaceous earth was purchased from Hebei Runhuabang New Material Technology Co., Ltd. The bio-organic fertilizer was purchased from Guangxi Qinglu Biotechnology Co., Ltd., a technology transfer product from Tsinghua University, with patent number ZL201310078539.4 and registration certificate number Nongfei (2018) Zhunzi 12363. The photosensitive organic carbon was purchased from Guangxi Qinglu Biotechnology Co., Ltd. ® Photosensitive organic carbon is an organic water-soluble fertilizer, with registration certificate number Microbial Fertilizer (2018) Approval No. (6158). The graphene gel suspension fertilizer, purchased from Guangxi Qinglu Biotechnology Co., Ltd., is a Jian Tu Wei Shi graphene gel suspension fertilizer, an organic water-soluble fertilizer, with registration certificate number Agricultural Fertilizer (2018) Approval No. 12364. Registered indicators: organic matter ≥120g / L; NPK ≥120g / L; Zn+B: 2g / L~10g / L; pH 7.0~9.0; water-insoluble matter ≤50g / L.

[0036] In the following embodiments, the method for preparing the decomposed sugarcane straw is as follows: Sugarcane straw and ammonium nitrate are mixed at a mass ratio of 10:1 to obtain a mixture. 990 kg of the mixture is mixed with 10 kg of EM bacteria (EM bacteria were purchased from Anhui Lingwo Biotechnology Co., Ltd., registration certificate number: Microbial Fertilizer (2021) No. 10618). Water is then added until the moisture content of the fermentation mixture is 60%. The mixture is mixed evenly to obtain a fermentation mixture. The fermentation mixture is covered with polyethylene agricultural film (film thickness 0.02 mm) (generally the temperature rises to a maximum of 70°C within 48 hours and remains there for a long time). The pile is turned over once on the 9th day and once again on the 15th day. Fermentation is carried out for 30 days to obtain decomposed sugarcane straw.

[0037] Example 1 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 5 kg fly ash, 3 kg slag, 2 kg organic peat, 1 kg coconut shell activated carbon, 1.5 kg coconut coir, 0.2 kg diatomaceous earth, 1 kg bio-organic fertilizer, 0.2 kg vermiculite, 1.5 kg decomposed sugarcane straw, 0.1 kg coconut shell, 0.1 kg photosensitive organic carbon, 0.2 kg SiC, and 2000 mL graphene gel suspension fertilizer dilution.

[0038] The preparation method of the fly ash-based matrix soil includes the following steps: 5 kg of fly ash, 3 kg of slag, 2 kg of organic peat, 1 kg of coconut shell activated carbon, 1.5 kg of coconut coir, 0.2 kg of diatomaceous earth, 1 kg of bio-organic fertilizer, 0.2 kg of vermiculite, 1.5 kg of decomposed sugarcane straw, 0.1 kg of coconut shell, 0.1 kg of photosensitive organic carbon, and 0.2 kg of SiC are mixed evenly and pulverized through a 50-mesh sieve to obtain a powder mixture. The powder mixture is conveyed to a disc granulator via a conveyor belt and granulated at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 2000 mL of graphene gel suspension fertilizer dilution is sprayed through atomization. Granulation is carried out for 15 min to obtain fly ash-based matrix soil.

[0039] The graphene gel suspension fertilizer dilution was prepared by mixing 1000 mL of water with 1 mL of graphene gel suspension fertilizer.

[0040] The fly ash-based matrix soil prepared in this embodiment has a particle size of 2~10mm.

[0041] Example 2 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 5 kg fly ash, 2 kg slag, 3 kg organic peat, 1 kg coconut shell activated carbon, 1 kg coconut coir, 0.2 kg diatomaceous earth, 1 kg bio-organic fertilizer, 0.2 kg vermiculite, 1.5 kg decomposed sugarcane straw, 0.1 kg coconut shell, 0.1 kg photosensitive organic carbon, 0.2 kg SiC, and 3000 mL graphene gel suspension fertilizer dilution.

[0042] The preparation method of the fly ash-based matrix soil includes the following steps: 5 kg of fly ash, 2 kg of slag, 3 kg of organic peat, 1 kg of coconut shell activated carbon, 1 kg of coconut coir, 0.2 kg of diatomaceous earth, 1 kg of bio-organic fertilizer, 0.2 kg of vermiculite, 1.5 kg of decomposed sugarcane straw, 0.1 kg of coconut shell, 0.1 kg of photosensitive organic carbon, and 0.2 kg of SiC are mixed evenly and pulverized through a 50-mesh sieve to obtain a powder mixture. The powder mixture is conveyed to a disc granulator via a conveyor belt and granulated at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 3000 mL of graphene gel suspension fertilizer dilution is sprayed through atomization. Granulation is carried out for 10 min to obtain fly ash-based matrix soil.

[0043] The graphene gel suspension fertilizer dilution was prepared by mixing 1000 mL of water with 1 mL of graphene gel suspension fertilizer.

[0044] The fly ash-based matrix soil prepared in this embodiment has a particle size of 0.5~10mm.

[0045] Example 3 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 6 kg fly ash, 3 kg slag, 2 kg organic peat, 1 kg coconut shell activated carbon, 1 kg coconut coir, 0.2 kg diatomaceous earth, 1 kg bio-organic fertilizer, 0.2 kg vermiculite, 1.5 kg decomposed sugarcane straw, 0.1 kg coconut shell, 0.1 kg photosensitive organic carbon, 0.2 kg SiC, and 1000 mL graphene gel suspension fertilizer dilution.

[0046] The preparation method of the fly ash-based matrix soil includes the following steps: Mix 6 kg of fly ash, 3 kg of slag, 2 kg of organic peat, 1 kg of coconut shell activated carbon, 1 kg of coconut coir, 0.2 kg of diatomaceous earth, 1 kg of bio-organic fertilizer, 0.2 kg of vermiculite, 1.5 kg of decomposed sugarcane straw, 0.1 kg of coconut shell, 0.1 kg of photosensitive organic carbon, and 0.2 kg of SiC evenly, pulverize the mixture through a 50-mesh sieve to obtain a powder. The powder is then conveyed to a disc granulator via a conveyor belt. Granulation is carried out in the disc granulator at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 1000 mL of graphene gel suspension fertilizer dilution is sprayed through atomization. Granulation is carried out for 5 min to obtain fly ash-based matrix soil.

[0047] The graphene gel suspension fertilizer dilution was prepared by mixing 500 mL of water with 1 mL of graphene gel suspension fertilizer.

[0048] The fly ash-based matrix soil prepared in this embodiment has a particle size of 0.1~2mm.

[0049] Example 4 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 6 kg fly ash, 2 kg slag, 3 kg organic peat, 1 kg coconut shell activated carbon, 1 kg coconut coir, 0.2 kg diatomaceous earth, 1 kg bio-organic fertilizer, 0.2 kg vermiculite, 1.5 kg decomposed sugarcane straw, 0.1 kg coconut shell, 0.1 kg photosensitive organic carbon, 0.2 kg SiC, and 3000 mL graphene gel suspension fertilizer dilution.

[0050] The preparation method of the fly ash-based matrix soil includes the following steps: 6 kg of fly ash, 2 kg of slag, 3 kg of organic peat, 1 kg of coconut shell activated carbon, 1 kg of coconut coir, 0.2 kg of diatomaceous earth, 1 kg of bio-organic fertilizer, 0.2 kg of vermiculite, 1.5 kg of decomposed sugarcane straw, 0.1 kg of coconut shell, 0.1 kg of photosensitive organic carbon, and 0.2 kg of SiC were mixed evenly and pulverized through a 50-mesh sieve to obtain a powder mixture. The powder mixture was conveyed to a disc granulator via a conveyor belt and granulated at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 3000 mL of graphene gel suspension fertilizer dilution was sprayed through atomization. Granulation was carried out for 15 min to obtain fly ash-based matrix soil.

[0051] The graphene gel suspension fertilizer dilution was prepared by mixing 500 mL of water with 1 mL of graphene gel suspension fertilizer.

[0052] The fly ash-based matrix soil prepared in this embodiment has a particle size of 2~10mm.

[0053] Example 5 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 7 kg fly ash, 2 kg slag, 3 kg organic peat, 1 kg coconut shell activated carbon, 1 kg coconut coir, 0.2 kg diatomaceous earth, 1 kg bio-organic fertilizer, 0.2 kg vermiculite, 1.5 kg decomposed sugarcane straw, 0.1 kg coconut shell, 0.1 kg photosensitive organic carbon, 0.2 kg SiC, and 5000 mL graphene gel suspension fertilizer dilution.

[0054] The preparation method of the fly ash-based matrix soil includes the following steps: 7 kg of fly ash, 2 kg of slag, 3 kg of organic peat, 1 kg of coconut shell activated carbon, 1 kg of coconut coir, 0.2 kg of diatomaceous earth, 1 kg of bio-organic fertilizer, 0.2 kg of vermiculite, 1.5 kg of decomposed sugarcane straw, 0.1 kg of coconut shell, 0.1 kg of photosensitive organic carbon, and 0.2 kg of SiC were mixed evenly and pulverized through a 50-mesh sieve to obtain a powder mixture. The powder mixture was conveyed to a disc granulator via a conveyor belt and granulated at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 5000 mL of graphene gel suspension fertilizer dilution was sprayed through atomization. Granulation was carried out for 15 min to obtain fly ash-based matrix soil.

[0055] The graphene gel suspension fertilizer dilution was prepared by mixing 1000 mL of water with 1 mL of graphene gel suspension fertilizer.

[0056] The fly ash-based matrix soil prepared in this embodiment has a particle size of 2~10mm.

[0057] Example 6 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 7 kg fly ash, 2 kg slag, 3 kg organic peat, 2 kg coconut shell activated carbon, 1 kg coconut coir, 0.2 kg diatomaceous earth, 1 kg bio-organic fertilizer, 0.2 kg vermiculite, 1.5 kg decomposed sugarcane straw, 0.1 kg coconut shell, 0.1 kg photosensitive organic carbon, 0.2 kg SiC, and 5000 mL graphene gel suspension fertilizer dilution.

[0058] The preparation method of the fly ash-based matrix soil includes the following steps: 7 kg of fly ash, 2 kg of slag, 3 kg of organic peat, 2 kg of coconut shell activated carbon, 1 kg of coconut coir, 0.2 kg of diatomaceous earth, 1 kg of bio-organic fertilizer, 0.2 kg of vermiculite, 1.5 kg of decomposed sugarcane straw, 0.1 kg of coconut shell, 0.1 kg of photosensitive organic carbon, and 0.2 kg of SiC were mixed evenly and pulverized through a 50-mesh sieve to obtain a powder mixture. The powder mixture was conveyed to a disc granulator via a conveyor belt and granulated at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 5000 mL of graphene gel suspension fertilizer dilution was sprayed through atomization. Granulation was carried out for 10 min to obtain fly ash-based matrix soil.

[0059] The graphene gel suspension fertilizer dilution was prepared by mixing 1000 mL of water with 1 mL of graphene gel suspension fertilizer.

[0060] The fly ash-based matrix soil prepared in this embodiment has a particle size of 0.5~10mm.

[0061] Example 7 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 7 kg fly ash, 2 kg slag, 3 kg organic peat, 1 kg coconut shell activated carbon, 2 kg coconut coir, 1 kg diatomaceous earth, 1 kg bio-organic fertilizer, 0.2 kg vermiculite, 1.5 kg decomposed sugarcane straw, 0.1 kg coconut shell, 0.1 kg photosensitive organic carbon, 0.2 kg SiC, and 5000 mL graphene gel suspension fertilizer dilution.

[0062] The preparation method of the fly ash-based matrix soil includes the following steps: 7 kg of fly ash, 2 kg of slag, 3 kg of organic peat, 1 kg of coconut shell activated carbon, 2 kg of coconut coir, 1 kg of diatomaceous earth, 1 kg of bio-organic fertilizer, 0.2 kg of vermiculite, 1.5 kg of decomposed sugarcane straw, 0.1 kg of coconut shell, 0.1 kg of photosensitive organic carbon, and 0.2 kg of SiC were mixed evenly and pulverized through a 50-mesh sieve to obtain a powder mixture. The powder mixture was conveyed to a disc granulator via a conveyor belt and granulated at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 5000 mL of graphene gel suspension fertilizer dilution was sprayed through atomization. Granulation was carried out for 10 min to obtain fly ash-based matrix soil.

[0063] The graphene gel suspension fertilizer dilution was prepared by mixing 500 mL of water with 1 mL of graphene gel suspension fertilizer.

[0064] The fly ash-based matrix soil prepared in this embodiment has a particle size of 0.5~10mm.

[0065] Example 8 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 7 kg fly ash, 2 kg slag, 3 kg organic peat, 1 kg coconut shell activated carbon, 2 kg coconut coir, 1 kg diatomaceous earth, 1 kg bio-organic fertilizer, 0.5 kg vermiculite, 2 kg decomposed sugarcane straw, 0.1 kg coconut shell, 0.1 kg photosensitive organic carbon, 0.2 kg SiC, and 4000 mL graphene gel suspension fertilizer dilution.

[0066] The preparation method of the fly ash-based matrix soil includes the following steps: 7 kg of fly ash, 2 kg of slag, 3 kg of organic peat, 1 kg of coconut shell activated carbon, 2 kg of coconut coir, 1 kg of diatomaceous earth, 1 kg of bio-organic fertilizer, 0.5 kg of vermiculite, 2 kg of decomposed sugarcane straw, 0.1 kg of coconut shell, 0.1 kg of photosensitive organic carbon, and 0.2 kg of SiC were mixed evenly and pulverized through a 50-mesh sieve to obtain a powder mixture. The powder mixture was conveyed to a disc granulator via a conveyor belt and granulated at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 4000 mL of graphene gel suspension fertilizer dilution was sprayed through atomization. Granulation was carried out for 5 min to obtain fly ash-based matrix soil.

[0067] The graphene gel suspension fertilizer dilution was prepared by mixing 1000 mL of water with 1 mL of graphene gel suspension fertilizer.

[0068] The fly ash-based matrix soil prepared in this embodiment has a particle size of 0.1~2mm.

[0069] Example 9 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 7 kg fly ash, 2 kg slag, 3 kg organic peat, 1 kg coconut shell activated carbon, 2 kg coconut coir, 1 kg diatomaceous earth, 1 kg bio-organic fertilizer, 0.5 kg vermiculite, 2 kg decomposed sugarcane straw, 0.1 kg coconut shell, 0.5 kg photosensitive organic carbon, 0.5 kg SiC, and 4000 mL graphene gel suspension fertilizer dilution.

[0070] The preparation method of the fly ash-based matrix soil includes the following steps: 7 kg of fly ash, 2 kg of slag, 3 kg of organic peat, 1 kg of coconut shell activated carbon, 2 kg of coconut coir, 1 kg of diatomaceous earth, 1 kg of bio-organic fertilizer, 0.5 kg of vermiculite, 2 kg of decomposed sugarcane straw, 0.1 kg of coconut shell, 0.5 kg of photosensitive organic carbon, and 0.5 kg of SiC were mixed evenly and pulverized through a 50-mesh sieve to obtain a powder mixture. The powder mixture was conveyed to a disc granulator via a conveyor belt and granulated at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 4000 mL of graphene gel suspension fertilizer dilution was sprayed through atomization. Granulation was carried out for 5 minutes to obtain fly ash-based matrix soil.

[0071] The graphene gel suspension fertilizer dilution was prepared by mixing 2000 mL of water with 1 mL of graphene gel suspension fertilizer.

[0072] The fly ash-based matrix soil prepared in this embodiment has a particle size of 0.1~2mm.

[0073] Comparative Example 1 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 7 kg of fly ash and 2 kg of slag.

[0074] The preparation method of the fly ash-based matrix soil includes the following steps: Mix 7 kg of fly ash and 2 kg of slag evenly, crush them through a 50-mesh sieve to obtain a powder mixture. The powder mixture is then conveyed to a disc granulator via a conveyor belt. In the disc granulator, granulation is carried out at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 1000 mL of water is sprayed through atomization. Granulation takes 15 minutes, and the particle size is 1~10 mm, thus obtaining fly ash-based matrix soil.

[0075] Comparative Example 2 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 6 kg of fly ash and 3 kg of slag.

[0076] The preparation method of the fly ash-based matrix soil includes the following steps: Mix 6 kg of fly ash and 3 kg of slag evenly, crush them through a 50-mesh sieve to obtain a powder mixture. The powder mixture is then conveyed to a disc granulator via a conveyor belt. In the disc granulator, granulation is carried out at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 1000 mL of water is sprayed through atomization. Granulation takes 15 minutes, and the particle size is 1~10 mm, thus obtaining fly ash-based matrix soil.

[0077] Comparative Example 3 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 5 kg of fly ash and 4 kg of slag.

[0078] The preparation method of the fly ash-based matrix soil includes the following steps: Mix 5 kg of fly ash and 4 kg of slag evenly, crush them through a 50-mesh sieve to obtain a powder mixture. The powder mixture is then conveyed to a disc granulator via a conveyor belt. In the disc granulator, granulation is carried out at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 1000 mL of water is sprayed through atomization. Granulation takes 15 minutes, and the particle size is 1~10 mm, thus obtaining fly ash-based matrix soil.

[0079] Comparative Example 4 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 3 kg of fly ash and 6 kg of slag.

[0080] The preparation method of the fly ash-based matrix soil includes the following steps: Mix 3 kg of fly ash and 6 kg of slag evenly, crush them through a 50-mesh sieve to obtain a powder mixture. The powder mixture is then conveyed to a disc granulator via a conveyor belt. In the disc granulator, granulation is carried out at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 1000 mL of water is sprayed through atomization. Granulation takes 15 minutes, and the particle size is 1~10 mm, thus obtaining fly ash-based matrix soil.

[0081] Comparative Example 5 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 7 kg of fly ash, 2 kg of slag, and 1 kg of organic peat.

[0082] The preparation method of the fly ash-based matrix soil includes the following steps: Mix 7 kg of fly ash, 2 kg of slag, and 1 kg of organic peat soil evenly, crush them through a 50-mesh sieve to obtain a powder mixture, and convey the powder mixture to a disc granulator via a conveyor belt. In the disc granulator, granulation is carried out at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 2000 mL of water is sprayed through atomization. Granulation takes 15 min and the particle size is 1~10 mm to obtain fly ash-based matrix soil.

[0083] Comparative Example 6 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 7 kg fly ash, 2 kg slag, 1 kg organic peat soil and 1 kg coconut shell activated carbon.

[0084] The preparation method of the fly ash-based matrix soil includes the following steps: Mix 7 kg of fly ash, 2 kg of slag, 1 kg of organic peat soil and 1 kg of coconut shell activated carbon evenly, crush them through a 50-mesh sieve to obtain a mixture powder. The mixture powder is conveyed to a disc granulator via a conveyor belt. In the disc granulator, granulation is carried out at an inclination angle of 33° and a rotation speed of 11 r / min. During granulation, 2000 mL of water is sprayed through atomization. Granulation takes 15 min and the particle size is 1~10 mm to obtain fly ash-based matrix soil.

[0085] Comparative Example 7 A fly ash-based matrix soil, wherein the fly ash-based matrix soil is composed of the following components by mass: 7 kg fly ash, 2 kg slag, 1 kg organic peat, 1 kg coconut shell activated carbon, 1 kg bio-organic fertilizer, 0.1 kg coconut shell, and 0.1 kg photosensitive organic carbon.

[0086] The preparation method of the fly ash-based matrix soil includes the following steps: Mix 7 kg of fly ash, 2 kg of slag, 1 kg of organic peat, 1 kg of coconut shell activated carbon, 1 kg of bio-organic fertilizer, 0.1 kg of coconut shell, and 0.1 kg of photosensitive organic carbon evenly, pulverize through a 50-mesh sieve to obtain a powder mixture, and convey the powder mixture to a disc granulator via a conveyor belt. Granulate in the disc granulator at an inclination angle of 33° and a rotation speed of 11 r / min. Spray 2000 mL of water atomized during granulation, and granulate for 15 min. The particle size is 1~10 mm, and fly ash-based matrix soil is obtained.

[0087] Comparative Example 8 The planting soil comes from the black soil of Heilongjiang (the organic fertilizer in this soil is equivalent to 1 ton / mu).

[0088] Experimental Example 1 The fly ash-based matrix soils prepared in Examples 1 to 9 (referred to as Examples 1 to 9), the fly ash-based matrix soils prepared in Comparative Examples 1 to 7 (referred to as Comparative Examples 1 to 7), and the planting soil of Comparative Example 8 (referred to as Comparative Example 8) were subjected to Zeta potential, bulk density, organic matter, and ammonium nitrogen (N) retention. Each measurement was performed in triplicate.

[0089] The bulk density was determined using the ring cutter method, and the organic matter was determined using the potassium dichromate volumetric method-dilution heat method.

[0090] Determination of Ammonium Nitrogen (N) Preservation: The experimental setup consisted of three parts: an upper water injection system, a middle soil column, and a lower leaching solution receiving device. The water injection system comprised an adjustable-flow 500mL titration bottle. The soil column container was a transparent tube with an inner diameter of 6cm and a height of 30cm, one end of which was sealed with a rubber stopper, with a 2cm circular hole in the center for the permeate to flow out. A layer of filter paper was placed on the rubber stopper at the bottom of the soil column to prevent soil particles from being lost with the water during leaching. After filling with the predetermined amount of soil, a 3mm thick layer of sand and gravel was laid on top of the soil column. This prevented damage to the surface soil layer during leaching and facilitated uniform water penetration. When slowly adding soil to the transparent tube, it was crucial to spread it evenly. Every 5cm of soil added required vibrating the tube to ensure even distribution and compacting the edges to prevent water seepage from the walls. The lower part of the setup contained a 250mL plastic cup for receiving the filtrate.

[0091] Leaching test method In the experimental setup, 500 g of different dry modified soils were weighed out, and then 0.1 g of water-soluble fertilizer containing macro-elements was weighed out. The fertilizer was then slowly and evenly added to the soil column containing soil using a titration device. The leaching experiment lasted for 5 hours. Each experimental group was set up with 3 replicates.

[0092] Collection and analysis of leached soil: The soil column is divided into three parts: upper (0-5cm), middle (5-10cm), and lower (10-15cm). The soil column is divided into three parts and taken out to air dry naturally. The parts are mixed evenly and passed through a 60-mesh sieve. The air-dried soil is placed in a beaker and stored in a cool place for later use.

[0093] Determination of ammonium nitrogen in soil: Ammonium nitrogen was determined using the K₂SO₄ extraction-indophenol blue colorimetric method. 1 g of dry soil was placed in a 100 mL Erlenmeyer flask, and 20 mL of K₂SO₄ solution was added. The flask was then placed on a magnetic stirrer at 500 rpm for 10 minutes. The mixture was then filtered through qualitative filter paper into a dry Erlenmeyer flask to obtain the soil available nutrient test solution. 2 mL of the test solution was pipetted into a test tube, and 5 mL of phenol solution and 5 mL of sodium hypochlorite alkaline solution were added. The mixture was shaken well, and after 5 minutes, it was transferred to a cuvette for measurement using a soil fertilizer nutrient analyzer.

[0094] The test results of different fly ash-based substrate soils and planting soils are shown in Table 1. The results in Table 1 are average values.

[0095] Table 1. Test results of properties of different fly ash-based substrate soils and planting soils

[0096] Zeta potential is the basis of soil colloidal structure. The larger the absolute value of the zeta potential, the better the aggregate structure of the soil colloid.

[0097] The results in Table 1 show that the absolute values ​​of the Zeta potential in Examples 1 to 9 are larger than those in Comparative Examples 1 to 7, and similar to those in Comparative Example 8, indicating that the fly ash-based matrix soils of Examples 1 to 9 have good soil colloid aggregate structure. Compared with the bulk density of the fly ash-based matrix soils in Comparative Examples 1 to 7, the bulk density of the fly ash-based matrix soils in Examples 1 to 9 is closer to that of the planting soil in Comparative Example 8. Compared with the organic matter content and ammonium nitrogen (N) retention of the fly ash-based matrix soils in Comparative Examples 1 to 7, the organic matter content and ammonium nitrogen (N) retention of the fly ash-based matrix soils in Examples 1 to 9 are higher, indicating that the fly ash-based matrix soils of Examples 1 to 9 have good performance.

[0098] Experimental Example 2 Using the fly ash-based substrate soil prepared in Examples 1-9 (denoted as Examples 1-9) and the planting soil of Comparative Example 8 (denoted as Comparative Example 8), 50 plants of bahia grass, 50 plants of wheat, and 100 plants of alfalfa were planted respectively. The planting methods for bahia grass, wheat, and alfalfa followed local planting practices. The germination rate of bahia grass was calculated as follows: Germination rate (%) = Number of germinated bahia grass plants ÷ Total number of bahia grass plants × 100. The germination rate was the average of the germination rates of the 50 bahia grass plants. One month after planting, the height of wheat plants was recorded to calculate wheat growth. The plant height was the average of the 50 wheat plants. Two months after planting alfalfa in the field, the height of alfalfa plants was recorded to calculate alfalfa growth. The plant height was the average of the 100 alfalfa plants.

[0099] Table 2 Results of the effects of different fly ash-based substrate soils and planting soils on crop growth traits

[0100] The results in Table 2 show that the fly ash-based matrix soil of the present invention can guarantee the germination rate of Bahia grass, the growth of wheat and alfalfa. In fact, compared with the planting soil of Comparative Example 8, the fly ash-based matrix soil prepared in Examples 1, 2 and 9 promotes the germination rate of Bahia grass, the growth of wheat and alfalfa.

[0101] Meanwhile, five months after wheat planting, the content of heavy metals arsenic, lead, cadmium, and mercury in wheat grains was statistically analyzed. The determination and calculation methods for the content of arsenic, lead, cadmium, and mercury were in accordance with NY / T 1938-2919 "Determination of Lead, Cadmium, Chromium, Mercury and Arsenic in Plants by Microwave Digestion-ICP-MS", and the evaluation was carried out in accordance with the requirements of the heavy metal limits in GB2762-2022 "National Food Safety Standard - Limits of Contaminants in Food". Six replicate experiments were set up for each experimental group.

[0102] The values ​​for the heavy metals arsenic, lead, cadmium, and mercury in each wheat grain in Table 3 are the average values ​​of the results from six repeated experiments.

[0103] Table 3. Results of heavy metal content determination in wheat from different fly ash-based substrates and planting soils.

[0104] The results in Table 3 show that wheat grown using the fly ash-based substrate soil of the present invention has low levels of arsenic, lead, cadmium, and mercury in the wheat grains. The levels of arsenic, lead, cadmium, and mercury in the wheat grains meet the heavy metal limits in GB2762-2022 "National Food Safety Standard - Limits of Contaminants in Food". This indicates that growing wheat using the fly ash-based substrate soil of the present invention will not cause toxicity to the wheat or lead to the accumulation of heavy metals in the crop.

[0105] Furthermore, the contents of heavy metals arsenic, lead, cadmium, and mercury, as well as pH, were determined in the fly ash-based matrix soils prepared in Examples 1 to 9 (referred to as Examples 1 to 9) and the planting soil of Comparative Example 8. The determination and calculation methods for the contents of arsenic, lead, cadmium, and mercury were in accordance with NY / T 1938-2919 "Determination of Lead, Cadmium, Chromium, Mercury and Arsenic in Plants by Microwave Digestion-ICP-MS". Six replicate experiments were set up for each experimental group.

[0106] Each result in Table 4 is the average of the results from 6 repeated experiments.

[0107] Table 4. Determination of heavy metal content in different coal ash-based matrix soils and planting soils.

[0108] The results in Table 4 show that the arsenic, lead, cadmium, and mercury content and pH of the fly ash-based matrix soil prepared by this invention are higher than those of the soil planted in Comparative Example 8. However, the arsenic, lead, cadmium, and mercury content of the fly ash-based matrix soil prepared by this invention meets the requirements of the soil pollution risk screening and control values ​​for garden and pasture soils specified in GB15618-2018 "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)". Therefore, the fly ash-based matrix soil of this invention can be used as soil for greening and forest land.

[0109] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A fly ash-based matrix soil, characterized in that, Including the following components: Fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC and graphene gel suspension fertilizer dilution; The mass-to-volume ratio of the diluted fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon, SiC, and graphene gel suspension fertilizer is (4~8) kg: (1~4) kg: (1~4) kg: (0.5~2.5) kg: (0.5~2.5) kg: (0.1~1.2) kg: (0.5~1.5) kg: (0.1~0.6) kg: (1~2.5) kg: (0.05~0.15) kg: (0.05~0.6) kg: (0.1~0.6) kg: (500~5000) mL.

2. The fly ash-based matrix soil according to claim 1, characterized in that, The method for preparing the decomposed sugarcane straw includes the following steps: Sugarcane stalks were mixed with ammonium nitrate to obtain a mixture; The mixture is mixed with EM bacteria, water is added, and the mixture is mixed evenly to obtain a fermentation mixture. Fermentation is carried out to obtain decomposed sugarcane straw. The diluted solution of the graphene gel suspension fertilizer is prepared by mixing water with the graphene gel suspension fertilizer.

3. The fly ash-based matrix soil according to claim 2, characterized in that, The mass ratio of sugarcane straw to ammonium nitrate is 8-12:1; the mass ratio of the mixture to EM bacteria is 980-1000:10; the water content added is such that the moisture content of the fermentation mixture is 55%-65%; during fermentation, the fermentation mixture is covered with polyethylene film, turned over once on the 7th-10th day of fermentation, and turned over again on the 11th-20th day of fermentation, and fermentation lasts for 25-35 days; The volume ratio of water to graphene gel suspension fertilizer is 500~2000:

1.

4. The method for preparing fly ash-based matrix soil according to any one of claims 1 to 3, characterized in that, Includes the following steps: The fly ash, slag, organic peat, coconut shell activated carbon, coconut coir, diatomaceous earth, bio-organic fertilizer, vermiculite, decomposed sugarcane straw, coconut shell, photosensitive organic carbon and SiC are mixed, crushed and sieved to obtain a mixture powder, granulated, and sprayed with graphene gel suspension fertilizer dilution during granulation to obtain fly ash-based matrix soil.

5. The preparation method according to claim 4, characterized in that, The pulverization and sieving process uses a mesh size of 40-60; during granulation, the tilt angle is 30°-35°, the rotation speed is 10-15 r / min, and the granulation time is 5-20 min.

6. The preparation method according to claim 4, characterized in that, The diluted solution of the graphene gel suspension fertilizer is prepared by mixing water with the graphene gel suspension fertilizer.

7. The preparation method according to claim 6, characterized in that, The volume ratio of water to graphene gel suspension fertilizer is 500~2000:

1.

8. The application of fly ash-based matrix soil according to any one of claims 1 to 3 or fly ash-based matrix soil prepared by the preparation method according to any one of claims 4 to 7 in promoting plant growth.

9. The application according to claim 8, characterized in that, The plant includes one or more of bahia grass, wheat, and alfalfa; the growth traits include germination rate and plant height.

10. A method for promoting plant growth, characterized in that, Includes the following steps: The plant is planted in the fly ash-based matrix soil according to any one of claims 1 to 3 or the fly ash-based matrix soil prepared by the preparation method according to any one of claims 4 to 7.

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