A soil conditioner for improving the structure of agglomerates and a method for preparing the same

Abstract

The application belongs to the technical field of soil conditioner synthesis, and particularly relates to a soil conditioner for improving aggregate structure and a preparation method thereof. The soil conditioner comprises the following raw materials in parts by weight: gasified slag 7-10 parts, fly ash 2.4-3.7 parts, starch 0.8-1.5 parts, kaolin 3-5 parts, chitosan 2.5-4 parts, sodium alginate 1-2 parts, carbon powder 0.3-0.5 parts, PVP 0.1-0.3 parts, light-heat material 0.6-0.9 parts and citric acid 0.3-0.6 parts. A porous ceramic skeleton is prepared from solid waste, kaolin and starch, the light-heat material is loaded and anchored, and a composite gel is coated, so that the soil conditioner for improving aggregate, adjusting pH and preventing soil compaction is prepared.

Description

Technical Field

[0001] This invention belongs to the field of soil conditioner synthesis technology, specifically referring to a soil conditioner that improves aggregate structure and its preparation method. Background Technology

[0002] Soil compaction and acidification are becoming increasingly serious problems.

[0003] Existing soil conditioners such as lime, organic fertilizer, and biochar either suffer from drawbacks such as easy acid reversion, long improvement cycles, and low mechanical strength, or have high energy consumption during preparation, weak binding force with soil, and difficulty in forming stable aggregate structures. Meanwhile, my country's coal chemical industry generates large amounts of industrial solid waste such as gasification slag and fly ash, and current utilization methods are mostly limited to low-value-added blending, failing to fully exploit the high-value potential of silicon, aluminum, calcium, and iron elements. While porous ceramic materials possess structural support advantages, conventional preparation methods often involve single-function pore-forming agents, a lack of synergistic design between pores and crystal phases, and their function is limited to physical improvement, unable to actively intervene in soil acidification and compaction. Furthermore, while photothermal materials such as TiO2 / C and Fe3O4 are widely used in energy and medical fields, they are currently lacking in agricultural soil improvement. Although organic gels such as chitosan-sodium alginate have water retention and pH adjustment functions, pure organic systems have low mechanical strength, are easily washed away, and have weak interfacial bonding with inorganic soil particles, making long-term stability difficult.

[0004] Therefore, developing composite soil conditioners that combine solid waste resource utilization, structural support, photothermal anti-caking properties, and organic-inorganic synergistic stability is of great significance for solving the dual problems of soil degradation and industrial solid waste disposal. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention discloses a soil conditioner for improving aggregate structure and its preparation method. Using gasification slag, fly ash, and kaolin as main materials, and starch as a pore-forming agent and carbon source, the process involves low-temperature carbonization to decompose starch, releasing CO2 and H2O to create pores in situ, leaving residual amorphous carbon. High-temperature calcination then causes a solid-phase reaction between fly ash and SiO2, Al2O3, CaO, and Fe2O3 in kaolin, generating in situ anorthite and iron-aluminum spinel crystal phases, forming a porous-crystalline composite ceramic framework. Subsequently, TiO2-Fe3O4 is introduced and calcined under an inert atmosphere, allowing amorphous carbon to coat the TiO2-Fe3O4 / C composite photothermal material. Simultaneously, Ti-O-Si and Ti-O-Al chemical bonds are formed through interfacial diffusion, achieving stable anchoring of the photocatalytic components. This photothermal conversion effect increases soil surface temperature and promotes water evaporation to alleviate hydration expansion and compaction. Finally, a chitosan-sodium alginate polyelectrolyte gel network is used to connect the soil with CaO and Fe2O3. 2+Cross-linking and metal ion coordination prolong the retention time of organic gels in soil, simultaneously achieving pH regulation of acidic soils and supply of carbon sources for microorganisms, ultimately resulting in an aggregate structure-modified soil conditioner with synergistic effects of inorganic porous framework and organic gel network.

[0006] To achieve the above objectives, the technical solution adopted by this invention is a soil conditioner for improving aggregate structure, comprising the following raw materials in parts by weight: 7-10 parts gasification slag, 2.4-3.7 parts fly ash, 0.8-1.5 parts starch, 3-5 parts kaolin, 2.5-4 parts chitosan, 1-2 parts sodium alginate, 0.3-0.5 parts carbon powder, 0.1-0.3 parts polyvinylpyrrolidone (PVP), 0.6-0.9 parts photothermal material, and 0.3-0.6 parts citric acid; Furthermore, the preparation method of the photothermal material includes the following steps: α. Weigh 0.05-0.15 parts of silane coupling agent and add them to 30 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 0.1-0.4 parts of sodium bicarbonate and add them to the mixture. Heat at 40-50℃ for 15-25 min to obtain a composite dispersion. β. Weigh 1.2-1.5 parts TiO2, 0.25-0.45 parts Fe3O4 and 0.2 parts red mud and ball mill them at 150 r / min for 30 min to obtain a photothermal substrate. Add the obtained photothermal substrate to 50 parts of composite acid solution, wherein the composite acid solution is composed of the following mass ratio of glacial acetic acid: deionized water = 1-1.5:9. Heat in a polytetrafluoroethylene hydrothermal reactor at 150-180℃ for 24 h. Wash with deionized water and anhydrous ethanol alternately 3 times each. Dry at 70℃ for 24 h to obtain the loaded powder. γ. The loaded powder obtained in step β is added to the composite dispersion obtained in step α, stirred at a speed of 500 r / min, heated in a polytetrafluoroethylene hydrothermal reactor at a temperature of 60-90℃ for 24 h, ground for 10 min, nitrogen gas with a flow rate of 100 mL / min is introduced, and calcined at a temperature of 400-600℃ for 2-4 h to obtain the photothermal material.

[0007] The present invention provides a method for preparing a soil conditioner that improves aggregate structure, comprising the following steps: Step 1. Weigh 7-10 parts of gasification slag, 2.4-3.7 parts of fly ash, 3-5 parts of kaolin, 0.8-1.5 parts of starch, and 0.3-0.5 parts of carbon powder and add them to 50 parts of alcohol solution. The alcohol solution is composed of the following mass ratio: ethanol:deionized water = 5-8:10. Stir at 500 r / min, and reflux at 5℃ for 6-10 h under normal pressure and oil bath temperature of 90-120℃. Filter and dry at 80℃ for 24 h to obtain calcined substrate. Grind the obtained calcined substrate for 10 min and calcine at 900-1200℃ for 4-6 h. Cool naturally to room temperature to obtain composite inorganic powder. Step 2. Weigh 0.6-0.9 parts of photothermal material, 0.3-0.6 parts of citric acid and the composite inorganic powder obtained in Step 1 and mix them. Ball mill the mixture at 300 r / min for 10 min, introduce nitrogen gas at a flow rate of 100 mL / min, and calcine it at 550-650℃ for 2-4 h. Allow it to cool naturally to room temperature to obtain the photothermal composite powder. Step 3. Weigh 2.5-4 parts of chitosan and 1-2 parts of sodium alginate and add them to 30 parts of deionized water. Stir at 500 r / min and reflux at 5°C for 24 h in an oil bath at 70-90°C. Weigh 0.1-0.3 parts of PVP and add them to the mixture. Add the photothermal composite powder obtained in Step 2 and continue heating at the above temperature for 12 h. Wash the mixture three times each with deionized water and anhydrous ethanol. Extrude the product into particles with a diameter of 3-5 mm and dry them at 70°C for 24 h to obtain a soil conditioner that improves the aggregate structure.

[0008] The beneficial effects achieved by this invention are as follows: The soil conditioner for improving aggregate structure prepared by this invention uses industrial solid waste gasification slag, fly ash, and kaolin as the main materials, and introduces starch as a pore-forming agent and carbon source. The starch gradually carbonizes and decomposes, releasing CO2 and H2O vapors, forming a porous structure in situ in the gasification slag matrix. At the same time, the generated amorphous carbon powder is dispersed in the pores and particle surfaces, serving as an in-situ reinforcing phase for subsequent high-temperature sintering, improving the mechanical strength of the ceramic skeleton. During high-temperature calcination in an air atmosphere, the fly ash reacts with SiO2, Al2O3, CaO, and Fe2O3 in the kaolin to generate crystalline phases such as CaAl2Si2O8 and FeAl2O4 in situ, which fill the pores as ceramic bonding phases, forming a porous-crystalline composite skeleton, thus realizing the high-value utilization of waste.

[0009] This invention prepares a soil conditioner that improves aggregate structure. It introduces a semiconductor photocatalytic material by blending the photothermal material with the aforementioned inorganic powder and calcining it under N2. This allows amorphous carbon to coat the TiO2 surface, forming a TiO2-Fe3O4 / C composite photothermal material. Simultaneously, TiO2 diffuses through the interface with SiO2 and Al2O3 in gasification slag and fly ash to form Ti-O-Si and Ti-O-Al chemical bonds, achieving stable anchoring of the photocatalytic active components on the inorganic framework. This TiO2-Fe3O4 / C composite material generates a photothermal conversion effect under sunlight irradiation, synergistically increasing the soil surface temperature, promoting water evaporation, and reducing soil compaction caused by hydration expansion. Furthermore, it introduces chitosan and sodium alginate to construct an organic gel network. Chitosan, as an alkaline polysaccharide, can regulate the pH of acidic soil and provide a carbon source for soil microorganisms; its -COO bond with sodium alginate... - Groups and Ca in soil 2+ The formation of polyelectrolyte composite gels through electrostatic interactions, while the -NH2 in chitosan forms coordination compounds with metal ions such as Ca and Al in kaolin, significantly improves the retention time of organic gels in soil and achieves synergistic aggregation and enhancement of inorganic porous framework and organic gel network. Attached Figure Description

[0010] Figure 1 This is a simplified flowchart of the preparation process of the soil conditioner for improving aggregate structure proposed in this invention; Figure 2 SEM images of TiO2 (a), Fe3O4 (b), and photothermal material (c) in Example 2; Figure 3 Infrared thermal imaging of the soil conditioner for improving aggregate structure prepared in Example 2; Figure 4 The test graph shows the water loss rate of the soil after application of the soil conditioner for improving aggregate structure prepared in the examples and comparative examples. Figure 5 The test graphs show the compressive strength of the soil conditioners for improving aggregate structure prepared in the examples and comparative examples; Figure 6 The test graph shows the bulk density of the soil after application of the soil conditioner for improving aggregate structure prepared in the examples and comparative examples. Figure 7 The pH test results of the soil after application of the soil conditioner for improving aggregate structure prepared in the examples and comparative examples are shown. Figure 8 The soil temperature test diagrams are shown for the soils after the application of the soil conditioners for improving aggregate structure prepared in the examples and comparative examples. Figure 9The test graph shows the organic carbon content of the soil after application of the soil conditioner for improving aggregate structure prepared for the examples and comparative examples. Figure 10 The BET test results are shown for the soil conditioners prepared in the examples and comparative examples to improve the aggregate structure.

[0011] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0012] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0014] The preparation method and performance in the following examples are as follows: Figures 1-10 Unless otherwise specified, all methods are conventional. Unless otherwise specified, the materials used in the following examples are calculated by mass. The calcination heating rate is 5℃ / min. The silane coupling agent is KH-550. The gasification slag, fly ash, kaolin and red mud are all screened using a 200-mesh screen.

[0015] Table 1 shows the main components and proportions involved in gasification slag, fly ash, kaolin, and red mud:

[0016] Example 1: A soil conditioner for improving aggregate structure, comprising the following raw materials in parts by weight: 7 parts gasification slag, 2.4 parts fly ash, 0.8 parts starch, 3 parts kaolin, 2.5 parts chitosan, 1 part sodium alginate, 0.3 parts carbon powder, 0.1 parts PVP, 0.6 parts photothermal material, and 0.3 parts citric acid; The preparation method of photothermal materials includes the following steps: α. Weigh 0.05 parts of silane coupling agent and add it to 30 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 0.1 parts of sodium bicarbonate and add it to the mixture. Heat at 40℃ for 15 min to obtain a composite dispersion. β. Weigh 1.2 parts TiO2, 0.25 parts Fe3O4 and 0.2 parts red mud and ball mill them at 150 r / min for 30 min to obtain a photothermal substrate. Add the obtained photothermal substrate to 50 parts of composite acid solution, wherein the composite acid solution is composed of the following materials by mass: 1 part glacial acetic acid and 9 parts deionized water. Heat in a polytetrafluoroethylene hydrothermal reactor at 150℃ for 24 h. Wash with deionized water and anhydrous ethanol alternately 3 times each. Dry at 70℃ for 24 h to obtain the loaded powder. γ. The loaded powder obtained in step β is added to the composite dispersion obtained in step α, stirred at a speed of 500 r / min, heated in a polytetrafluoroethylene hydrothermal reactor at a temperature of 60℃ for 24 h, ground for 10 min, nitrogen gas with a flow rate of 100 mL / min is introduced, and calcined at a temperature of 400℃ for 2 h to obtain the photothermal material.

[0017] This embodiment also provides a method for preparing a soil conditioner that improves aggregate structure, the steps of which are as follows: Step 1. Weigh 7 parts of gasification slag, 2.4 parts of fly ash, 3 parts of kaolin, 0.8 parts of starch, and 0.3 parts of carbon powder and add them to 50 parts of alcohol solution. The alcohol solution is composed of the following materials by mass: 5 parts of ethanol and 10 parts of deionized water. Stir at 500 r / min, and heat under normal pressure at 90℃ in an oil bath at 5℃ for 6 hours. Filter and dry at 80℃ for 24 hours to obtain calcined substrate. Grind the obtained calcined substrate for 10 minutes and calcine at 900℃ for 4 hours. Cool naturally to room temperature to obtain composite inorganic powder. Step 2. Weigh 0.6 parts of photothermal material, 0.3 parts of citric acid and the composite inorganic powder obtained in Step 1 and mix them. Ball mill the mixture for 10 minutes at a speed of 300 r / min. Then, introduce nitrogen gas at a flow rate of 100 mL / min and calcine it at a temperature of 550℃ for 2 hours. Allow it to cool naturally to room temperature to obtain the photothermal composite powder. Step 3. Weigh 2.5 parts chitosan and 1 part sodium alginate and add them to 30 parts deionized water. Stir at 500 r / min and reflux at 5°C for 24 h in an oil bath at 70°C. Weigh 0.1 parts PVP and add them to the mixture. Add the photothermal composite powder obtained in Step 2 and continue heating at the above temperature for 12 h. Wash the mixture three times each with deionized water and anhydrous ethanol. Extrude the product into particles with a diameter of 3-5 mm and dry them at 70°C for 24 h to obtain a soil conditioner that improves the aggregate structure.

[0018] Example 2: A soil conditioner for improving aggregate structure, comprising the following raw materials in parts by weight: 8.5 parts gasification slag, 3 parts fly ash, 1.2 parts starch, 4 parts kaolin, 3.3 parts chitosan, 1.5 parts sodium alginate, 0.4 parts carbon powder, 0.2 parts PVP, 0.8 parts photothermal material, and 0.5 parts citric acid; The preparation method of photothermal materials includes the following steps: α. Weigh 0.1 parts of silane coupling agent and add them to 30 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 0.3 parts of sodium bicarbonate and add them to the mixture. Heat at 45℃ for 20 min to obtain a composite dispersion. β. Weigh 1.4 parts TiO2, 0.35 parts Fe3O4 and 0.2 parts red mud and ball mill them at 150 r / min for 30 min to obtain a photothermal substrate. Add the obtained photothermal substrate to 50 parts of composite acid solution, wherein the composite acid solution is composed of the following materials by mass: 1.3 parts glacial acetic acid and 9 parts deionized water. Heat in a polytetrafluoroethylene hydrothermal reactor at 170℃ for 24 h. Wash with deionized water and anhydrous ethanol alternately 3 times each. Dry at 70℃ for 24 h to obtain the loaded powder. γ. The loaded powder obtained in step β is added to the composite dispersion obtained in step α, stirred at a speed of 500 r / min, heated in a polytetrafluoroethylene hydrothermal reactor at a temperature of 80℃ for 24 h, ground for 10 min, nitrogen gas with a flow rate of 100 mL / min is introduced, and calcined at a temperature of 500℃ for 3 h to obtain the photothermal material.

[0019] This embodiment also provides a method for preparing a soil conditioner that improves aggregate structure, the steps of which are as follows: Step 1. Weigh 8.5 parts of gasification slag, 3 parts of fly ash, 4 parts of kaolin, 1.2 parts of starch and 0.4 parts of carbon powder and add them to 50 parts of alcohol solution. The alcohol solution is composed of the following materials by mass: 7 parts of ethanol and 10 parts of deionized water. Stir at 500 r / min, and heat under normal pressure at 110℃ in an oil bath at 5℃ for 8 hours. Filter and dry at 80℃ for 24 hours to obtain calcined substrate. Grind the obtained calcined substrate for 10 minutes and calcine at 1050℃ for 5 hours. Cool naturally to room temperature to obtain composite inorganic powder. Step 2. Weigh 0.8 parts of photothermal material, 0.5 parts of citric acid and the composite inorganic powder obtained in Step 1 and mix them. Ball mill the mixture for 10 minutes at a speed of 300 r / min. Then, introduce nitrogen gas at a flow rate of 100 mL / min and calcine it at a temperature of 600℃ for 3 hours. Allow it to cool naturally to room temperature to obtain the photothermal composite powder. Step 3. Weigh 3.3 parts chitosan and 1.5 parts sodium alginate and add them to 30 parts deionized water. Stir at 500 r / min and reflux at 5°C for 24 h in an oil bath at 80°C. Weigh 0.2 parts PVP and add them to the mixture. Add the photothermal composite powder obtained in Step 2 and continue heating at the above temperature for 12 h. Wash the mixture three times each with deionized water and anhydrous ethanol. Extrude the product into particles with a diameter of 3-5 mm and dry them at 70°C for 24 h to obtain a soil conditioner that improves the aggregate structure.

[0020] Example 3: A soil conditioner for improving aggregate structure, comprising the following raw materials in parts by weight: 10 parts gasification slag, 3.7 parts fly ash, 1.5 parts starch, 5 parts kaolin, 4 parts chitosan, 2 parts sodium alginate, 0.5 parts carbon powder, 0.3 parts PVP, 0.9 parts photothermal material, and 0.6 parts citric acid; The preparation method of photothermal materials includes the following steps: α. Weigh 0.15 parts of silane coupling agent and add them to 30 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 0.4 parts of sodium bicarbonate and add them to the mixture. Heat at 50℃ for 25 min to obtain a composite dispersion. β. Weigh 1.5 parts TiO2, 0.45 parts Fe3O4 and 0.2 parts red mud and ball mill them at 150 r / min for 30 min to obtain a photothermal substrate. Add the obtained photothermal substrate to 50 parts of composite acid solution, wherein the composite acid solution is composed of the following materials by mass: 1.5 parts glacial acetic acid and 9 parts deionized water. Heat in a polytetrafluoroethylene hydrothermal reactor at 180℃ for 24 h. Wash with deionized water and anhydrous ethanol alternately 3 times each. Dry at 70℃ for 24 h to obtain the loaded powder. γ. The loaded powder obtained in step β is added to the composite dispersion obtained in step α, stirred at a speed of 500 r / min, heated in a polytetrafluoroethylene hydrothermal reactor at a temperature of 90℃ for 24 h, ground for 10 min, nitrogen gas with a flow rate of 100 mL / min is introduced, and calcined at a temperature of 600℃ for 4 h to obtain the photothermal material.

[0021] This embodiment also provides a method for preparing a soil conditioner that improves aggregate structure, the steps of which are as follows: Step 1. Weigh 10 parts of gasification slag, 3.7 parts of fly ash, 5 parts of kaolin, 1.5 parts of starch and 0.5 parts of carbon powder and add them to 50 parts of alcohol solution. The alcohol solution is composed of the following materials by mass: 8 parts of ethanol and 10 parts of deionized water. Stir at 500 r / min, and heat under normal pressure at 120℃ in an oil bath at 5℃ for 10 h. Filter and dry at 80℃ for 24 h to obtain calcined substrate. Grind the obtained calcined substrate for 10 min and calcine at 1200℃ for 6 h. Cool naturally to room temperature to obtain composite inorganic powder. Step 2. Weigh 0.9 parts of photothermal material, 0.6 parts of citric acid and the composite inorganic powder obtained in Step 1 and mix them. Ball mill the mixture for 10 minutes at a speed of 300 r / min. Then, introduce nitrogen gas at a flow rate of 100 mL / min and calcine it at a temperature of 650℃ for 4 hours. Allow it to cool naturally to room temperature to obtain the photothermal composite powder. Step 3. Weigh 4 parts chitosan and 2 parts sodium alginate and add them to 30 parts deionized water. Stir at 500 r / min and reflux at 5°C for 24 h in an oil bath at 90°C. Weigh 0.3 parts PVP and add them to the mixture. Add the photothermal composite powder obtained in Step 2 and continue heating at the above temperature for 12 h. Wash the mixture three times each with deionized water and anhydrous ethanol. Extrude the product into particles with a diameter of 3-5 mm and dry them at 70°C for 24 h to obtain a soil conditioner that improves the aggregate structure.

[0022] Comparative example: The difference between Comparative Example 1 and Example 2 is that no photothermal material was added; the rest is the same as Example 2. The difference between Comparative Example 2 and Example 2 is that chitosan and sodium alginate were not added; the rest of the parts are the same as Example 2. The difference between Comparative Example 3 and Example 2 is that no starch was added; the rest of the parts are the same as Example 2. The difference between Comparative Example 4 and Example 2 is that TiO2 is used as the photothermal material, while the rest is the same as Example 2; Comparative Example 5 is soil that has not undergone any treatment.

[0023] The following tests were conducted to assess the performance of the soil conditioners for improving aggregate structure prepared in the examples and comparative examples: Figure 2(a) and (b) are SEM images of TiO2 and Fe3O4 in Example 2, respectively. It can be seen that both exhibit irregular blocky morphology. Figure 2 (c) is a SEM image of the photothermal material in Example 2. It can be seen that TiO2 and Fe3O4 are in close contact, indicating successful composite formation. Figure 3 The image shows an infrared thermal image of the soil conditioner prepared in Example 2, created using an infrared thermal imager (FLIR T540, resolution 320×240, thermal sensitivity <30 mK) and a xenon lamp solar simulator (AM 1.5G filter, light intensity 100 mW / cm²). 2 The test was conducted at an ambient temperature of 25±1℃ and a relative humidity of 50±5%. The sample powder was spread evenly on a polytetrafluoroethylene heat-insulating substrate (5mm thick), with a stack thickness of about 2mm. The total test duration was 300s, and the surface center temperature was recorded. It can be seen that as the light irradiation time increased, the surface temperature of the material continued to rise to 61.5℃, indicating that the prepared soil conditioner has good photothermal performance. Figure 4 To test the soil water loss rate after application of the soil conditioner prepared in the examples and comparative examples, the soil conditioner was mixed at 2 wt% with air-dried soil that had passed through a 2 mm sieve, and the mixture was placed in a 9 cm diameter petri dish (soil layer thickness 2 cm). The initial moisture content was adjusted to 80% of the field capacity, and the mixture was subjected to constant temperature of 25°C and xenon lamp irradiation (100 mW / cm²). 2 Under these conditions, weigh the total mass of the petri dish after 6 hours, and calculate the cumulative water loss rate (%) using the formula: (m0 - m) t ) / (m0- m 干土 -m 皿 ) ×100% calculation, where m0 is the initial total mass, m t Let m be the total mass at time t. 干土 To determine the soil mass after drying to constant weight, m 皿 The quality of the petri dish is shown; it can be seen that the cumulative water loss rate of the example after 6 hours of light exposure is significantly higher than that of the comparative example, indicating that the introduction of photothermal materials is beneficial to the evaporation of water in the soil. Figure 5 The compressive strength test results of the soil conditioners prepared in the examples and comparative examples are shown below. The compressive strength of a single particle was determined using an intelligent particle strength testing machine (range 0-500N, accuracy 0.1N). Ten conditioner particles with a particle diameter of 3-5mm were randomly selected from Examples 1-2 and Comparative Examples 1-4 and applied vertically at a constant rate of 1mm / min. The maximum pressure value when the particles broke was recorded. The average value of 10 tests was taken. It can be seen that the compressive strength of the soil conditioner in the examples is higher than that in the comparative examples, indicating that it has higher structural strength. Figure 6 The soil bulk density test results after soil conditioner application are shown in the examples and comparative examples. The soil bulk density was determined according to NY / T 1121.4-2006 using a volume of 200 cm³.3 The test was conducted using a stainless steel ring cutter (5.4 cm high, 5.05 cm in diameter). The conditioner and soil were mixed at a mass ratio of 1:50, then the mixture was placed into the ring cutter. After natural settling, the mixture was leveled and dried at 105℃ to constant weight. The final weight was calculated using the formula ρb = m 干 / V is used to calculate the bulk density, with units of g / cm³. 3 The result is as follows Figure 6 As shown, the soil bulk density after application in the embodiment is significantly lower than that in the comparative example. Figure 7 The pH test results of the soil after application of the soil conditioner prepared for the examples and comparative examples were obtained by measuring the pH of the soil using a pH meter (Mettler Toledo FE28, equipped with a composite electrode) according to NY / T1377-2007, with a water-to-soil ratio of 2.5:1 (m / V), magnetic stirring for 30 min, and standing for 30 min. The pH of the supernatant was measured after each sample was measured three times and the average value was taken. The pH was calibrated with standard buffer solutions with pH values ​​of 4.01, 6.86, and 9.18 before the measurement. It can be seen that the pH of the prepared soil conditioner tends to be neutral overall. Figure 8 The surface temperature of the soil after 30 minutes of sunlight exposure following application of the soil conditioner prepared for the examples and comparative examples was measured. The soil conditioner was mixed with air-dried soil (passed through a 2 mm sieve) at a ratio of 1:50 (by mass), and the mixture was placed in plastic flowerpots (15 cm in diameter, 10 cm in height). The moisture content was adjusted to 20%. Measurements were taken using a K-type thermocouple (accuracy ±0.1℃, probe inserted 1 cm into the soil surface) in conjunction with an infrared thermal imager. The light source was a xenon lamp solar simulator (AM 1.5G, 100 mW / cm²). 2 The temperature was read immediately after 30 minutes of light exposure; it can be seen that the temperature of Example 2 reached 44.7℃, which is much higher than the soil temperature of the comparative example. Figure 9 The relative organic carbon content of the soil conditioner prepared for the examples and comparative examples was tested on day 30 after application. The determination was performed using the potassium dichromate external heating method according to NY / T 1121.6-2006. A 0-5 cm layer of topsoil was taken, air-dried, and sieved through a 0.25 mm sieve. 0.3 g of soil sample was weighed, and 10.00 mL of 0.8000 mol / L (1 / 6 K2Cr2O7) standard solution and 20 mL of concentrated sulfuric acid were added. The mixture was boiled in an oil bath at 170℃ for 5 min. After cooling, titration was performed using o-phenanthroline as an indicator with 0.2 mol / L ferrous sulfate standard solution. The organic carbon content was calculated using the formula: Organic carbon content = c × (V0 - V) × 0.003 × 1.1 / m × 1000 (g / kg). The organic carbon residue rate (%) was calculated using the formula: C 30 Calculate / C0 × 100%, where C 30The organic carbon content is 30 days, C0 is the initial organic carbon content, and Comparative Example 5 is the original soil without the application of the soil conditioner. The residual rate of organic carbon content reflects the natural retention of background organic carbon in the soil. It can be seen that after 30 days of application, the relative value of organic carbon in the soil after the application of the soil conditioner prepared in Example 2 reaches more than 80%, which is much higher than that of the comparative example. Figure 10 For the BET specific surface area test results of the soil conditioners in the examples and comparative examples, the samples were ground through a 200-mesh sieve, and 0.3 g was taken and degassed under vacuum at 120℃ for 6 h. N2 adsorption-desorption tests were then conducted at liquid nitrogen temperature (77 K), with the relative pressure P / P0 ranging from 0.15 to 0.25. The specific surface area was calculated using the multi-point BET method, with units in m². 2 / g, each sample was tested twice and the average value was taken, with a relative deviation of <5%; it can be seen that the specific surface area of ​​the example is significantly higher than that of the comparative examples.

[0024] The above descriptions are merely some embodiments and comparative examples of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention should still fall within the scope of the present invention.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0026] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A soil conditioner for improving aggregate structure, characterized in that, The raw materials include the following parts by weight: 7-10 parts gasification slag, 2.4-3.7 parts fly ash, 0.8-1.5 parts starch, 3-5 parts kaolin, 2.5-4 parts chitosan, 1-2 parts sodium alginate, 0.3-0.5 parts carbon powder, 0.1-0.3 parts polyvinylpyrrolidone, 0.6-0.9 parts photothermal material, and 0.3-0.6 parts citric acid; The preparation method of the photothermal material includes the following steps: α. Weigh the silane coupling agent and add it to water, stir, weigh the sodium bicarbonate and add it, heat, and obtain a composite dispersion; β. TiO2, Fe3O4 and red mud are ball-milled to obtain a photothermal substrate. The photothermal substrate is added to a composite acid solution and heated to obtain a supported powder. γ. The loaded powder is added to the composite dispersion, heated, aerated, and calcined to obtain the photothermal material.

2. The soil conditioner for improving aggregate structure according to claim 1, characterized in that, The raw material mass ratio of the photothermal material is as follows: TiO2:Fe3O4:silane coupling agent:red mud:sodium bicarbonate = 1.2-1.5:0.25-0.45:0.05-0.15:0.2:0.1-0.

4.

3. The soil conditioner for improving aggregate structure according to claim 1, characterized in that, The heating temperature in step α is 40-50℃, and the heating time is 15-25 minutes.

4. The soil conditioner for improving aggregate structure according to claim 1, characterized in that, The composite acid solution described in step β is composed of materials in the following mass ratio: glacial acetic acid: water = 1-1.5:9, and the heating temperature is 150-180℃.

5. The soil conditioner for improving aggregate structure according to claim 1, characterized in that, The heating temperature described in step γ is 60-90℃.

6. The soil conditioner for improving aggregate structure according to claim 1, characterized in that, The calcination temperature in step γ is 400-600℃, the calcination time is 2-4 hours, and the gas used for ventilation is nitrogen.

7. A method for preparing a soil conditioner for improving aggregate structure as described in any one of claims 1-6, characterized in that, The steps are as follows: Step 1. Weigh the gasification slag, fly ash, kaolin and carbon powder and add them to the alcohol solution. Stir and heat to obtain the calcined substrate. Grind the calcined substrate and calcinate it to obtain the composite inorganic powder. Step 2. Weigh the photothermal material, citric acid, and composite inorganic powder, mix them, ball mill, ventilate, and calcine to obtain the photothermal composite powder; Step 3. Weigh chitosan and sodium alginate and add them to water, stir, heat, weigh polyvinylpyrrolidone and add, add photothermal composite powder, heat, wash, granulate, and dry to obtain a soil conditioner that improves aggregate structure.

8. The method for preparing the soil conditioner for improving aggregate structure according to claim 7, characterized in that, The alcohol solution described in step one is composed of materials in the following mass ratio: ethanol:water = 5-8:10, the calcination temperature is 900-1200℃, and the calcination time is 4-6 hours.

9. The method for preparing the soil conditioner for improving aggregate structure according to claim 7, characterized in that, The calcination temperature described in step two is 550-650℃.

10. The method for preparing the soil conditioner for improving aggregate structure according to claim 7, characterized in that, The heating temperature described in step three is 70-90℃.

Images