Method for preparing nutrient soil by using slag, slurry and silt

Abstract

This invention relates to the field of nutrient soil technology, specifically providing a method for preparing nutrient soil using slag, mud, and silt. The slag, mud, and silt are pretreated and then mixed with phosphorus-doped biomass porous carbon, sodium tripolyphosphate, bagasse, sodium alginate, wood ash, boric acid, and a nonionic surfactant. After composting and fermentation, the mixture is dried and sieved to obtain the nutrient soil. The method proposed in this invention effectively improves the nutrient content, water retention, and aeration of the nutrient soil, enhances soil fertility and soil improvement effects, and simultaneously achieves resource utilization of waste, resulting in significant economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of nutrient soil technology, specifically to a method for preparing nutrient soil using slag, mud, and silt. Background Technology

[0002] Currently, there are various methods for preparing nutrient soil, but traditional methods mostly rely on mixing natural soil, chemical fertilizers, and organic waste. However, with the acceleration of urbanization, the amount of construction waste such as slag, mud, and silt has increased dramatically. These wastes are often directly landfilled or piled up without treatment, not only occupying a large amount of land resources but also potentially polluting the environment. Traditional methods for preparing nutrient soil cannot effectively utilize these wastes, leading to resource waste and an increased environmental burden. In addition, the excessive use of chemical fertilizers easily leads to soil salinization and fertility decline; long-term reliance on chemical fertilizers will damage soil structure, affecting crop growth and the stability of the ecological environment.

[0003] Existing technologies have significant limitations in treating construction waste and preparing high-quality nutrient soil. Many methods fail to fully consider the principles of waste reuse and the circular economy, and lack systematic research on the resource utilization of waste such as slag, mud, and silt. In particular, existing processes are complex, costly, and inadequate in terms of nutrient balance, water retention, and aeration in nutrient soil. In summary, current technologies urgently need improvement to achieve efficient utilization of construction waste and production of high-quality nutrient soil, meeting the demands of modern agriculture and horticulture for environmentally friendly and resource-saving soil conditioners. Summary of the Invention

[0004] In view of the above situation and to overcome the defects of the prior art, the present invention provides a method for preparing nutrient soil using slag, mud and silt.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention proposes a method for preparing nutrient soil using slag, mud, and silt, specifically including the following steps: S1. Use a crusher to crush the slag and obtain slag particles with a particle size of 10~20 mm; S2. Pre-treat the mud and sludge by using a slag and sand removal device to remove impurities from the mud and sludge respectively, and then further dewater them by centrifugal thickening device. The moisture content of the dewatered mud and sludge is 20-30%. S3. Add 40-50 parts by weight of slag particles, 20-30 parts by weight of dewatered slurry and 20-30 parts by weight of dewatered sludge to a mixer and mix evenly to obtain a slag-slurry-sludge mixture. S4. Add 2-5 parts by weight of phosphorus-doped biomass porous carbon, 1-3 parts by weight of sodium tripolyphosphate, 10-15 parts by weight of bagasse, 2-4 parts by weight of sodium alginate, 2-5 parts by weight of wood ash, 0.5-1 parts by weight of boric acid, and 0.5-1 parts by weight of nonionic surfactant to the mixture prepared in step S3 to obtain mixed soil material. S5. Ferment the mixed soil material using a mixed pile fermentation method, adjust the humidity to 40%~50%, seal it, and ferment at 50~60℃ for 5~7 days. S6. Adjust the humidity of the mixed soil after fermentation in step S5 to 50%~60%, and maintain it at 50~60℃ for secondary fermentation for 4~6 days. During this period, turn the mixed soil every 24 hours to ensure oxygen supply. S7. After the secondary fermentation in step S6, the mixed soil is dried at 70°C until the moisture content is 10%, and then sieved through a 100-mesh sieve to obtain nutrient soil.

[0006] Preferably, the method for preparing the phosphorus-doped biomass porous carbon includes the following steps: ① Wash the biomass waste with water, put it in an oven at 80~100℃ and dry it for 12 hours, then put it in a pulverizer to pulverize it to obtain biomass powder with a diameter of 2±0.5 mm; ② Weigh 4-5 g of the biomass powder prepared in step ① and mix it evenly with 1-2 g of potassium carbonate and 1-2 g of dipotassium hydrogen phosphate. Place the mixture in the constant temperature zone of a tube furnace and heat it to 800-900℃ at a rate of 5℃ / min under the continuous protection of nitrogen gas at a flow rate of 100 mL / min. Heat it at this temperature for 2-4 h and then let it cool naturally to room temperature to obtain the high-temperature carbonization product. ③ The high-temperature carbonization product prepared in step ② is washed three times with 0.5 mol / L dilute hydrochloric acid to remove impurities, and then washed three times with water to remove hydrochloric acid. It is then placed in an oven and dried at 80~100℃ for 12 h to obtain phosphorus-doped biomass porous carbon.

[0007] Preferably, the biomass waste in step ① is any one of sugarcane bagasse, corn stalks, or rice straw.

[0008] Preferably, the nonionic surfactant is any one of Tween 20, Tween 80, or alkyl glycoside APG0810.

[0009] The beneficial effects achieved by this invention are as follows: This invention utilizes slag, mud, and silt to prepare nutrient soil, effectively solving the problem of resource utilization of construction waste and producing high-quality nutrient soil. By adding phosphorus-doped biomass porous carbon, sodium tripolyphosphate, bagasse, sodium alginate, wood ash, and boric acid to the nutrient soil, not only are the nutrient content, water retention, and aeration properties of the nutrient soil improved, but the soil fertility and improvement effect are also enhanced, effectively meeting the needs of modern agriculture and horticulture for environmentally friendly and resource-saving soil conditioners.

[0010] Specifically, phosphorus-doped biomass porous carbon, through high-temperature carbonization and chemical activation during preparation, possesses a large specific surface area and abundant pore structure, enabling it to slowly release phosphorus, continuously providing nutrients to plants and improving soil water retention and aeration. Sodium tripolyphosphate, as a highly efficient phosphate fertilizer, promotes root development and growth, also exhibiting the characteristic of slowly releasing phosphorus, thereby enhancing crop resistance and yield. The slow phosphorus release capabilities of phosphorus-doped biomass porous carbon and sodium tripolyphosphate not only extend the effective lifespan of phosphorus in the nutrient soil, avoiding environmental pollution problems caused by excessive phosphate fertilizer use, but also continuously provide plants with the necessary phosphorus nutrition, promoting healthy plant growth. Sugarcane bagasse, as a source of organic matter, not only provides abundant organic carbon but also improves soil structure, increases soil aeration and water retention, and facilitates microbial reproduction and activity. Sodium alginate, through its unique water-retention properties, can significantly improve soil water-holding capacity, reduce water loss, and ensure plant growth under drought conditions. Wood ash is rich in potassium and other trace elements, which help improve soil fertility and balance. Furthermore, boric acid, an important trace element, promotes plant growth and development. The addition of surfactants improves the adhesion and dispersibility of soil particles, further optimizing soil structure and properties.

[0011] Throughout the preparation process, high-temperature composting and secondary fermentation not only effectively eliminate harmful substances from the waste, but also transform organic matter into plant-usable nutrients through microbial decomposition and transformation, further improving the quality and effectiveness of the nutrient soil. The nutrient soil prepared using this method is rich in nutrients, has good water retention, strong aeration, and long-lasting fertility, significantly promoting plant growth while realizing the resource utilization of waste, resulting in significant economic and environmental benefits.

[0012] Furthermore, the innovation of the phosphorus-doped biomass porous carbon and sodium tripolyphosphate in this invention lies in their ability to slowly release phosphorus. This characteristic not only extends the shelf life of phosphorus in the nutrient soil, avoiding the environmental pollution problems caused by excessive use of phosphate fertilizers, but also continuously provides plants with the necessary phosphorus nutrition, promoting healthy plant growth. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a scanning electron microscope image of the phosphorus-doped biomass porous carbon prepared in Example 1. Detailed Implementation

[0015] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0016] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.

[0017] Example 1: This example proposes a method for preparing nutrient soil using slag, mud, and silt, specifically including the following steps: S1. Use a crusher to crush the slag and obtain slag particles with a particle size of 10 mm. S2. Pre-treat the mud and sludge by using a slag and sand removal device to remove impurities from the mud and sludge respectively, and then further dewater them by centrifugal thickening device. The moisture content of the dewatered mud and sludge is 20%. S3. Add 45 parts by weight of slag particles, 20 parts by weight of dewatered slurry and 30 parts by weight of dewatered sludge to a mixer and mix evenly to obtain a slag-slurry-sludge mixture. S4. Add 5 parts by weight of phosphorus-doped biomass porous carbon, 2 parts by weight of sodium tripolyphosphate, 12 parts by weight of bagasse, 4 parts by weight of sodium alginate, 3 parts by weight of wood ash, 0.5 parts by weight of boric acid, and 0.5 parts by weight of Tween 20 to the mixture prepared in step S3 to obtain mixed soil. S5. Ferment the mixed soil material using a mixed pile fermentation method, adjust the humidity to 45%, seal it, and ferment at 50℃ for 5 days. S6. Adjust the humidity of the mixed soil after fermentation in step S5 to 55%, and keep it at 60℃ for secondary fermentation for 6 days. During this period, turn the mixed soil every 24 hours to ensure oxygen supply. S7. After the secondary fermentation in step S6, the mixed soil is dried at 70°C until the moisture content is 10%, and then sieved through a 100-mesh sieve to obtain nutrient soil.

[0018] The method for preparing phosphorus-doped biomass porous carbon includes the following steps: ① Wash the sugarcane bagasse with water, dry it in an oven at 80℃ for 12 hours, and then grind it in a pulverizer to obtain biomass powder with a diameter of 2±0.5 mm. ② Weigh 5 g of the biomass powder prepared in step ① and mix it evenly with 2 g of potassium carbonate and 2 g of dipotassium hydrogen phosphate. Place it in the constant temperature zone of a tube furnace and heat it to 900℃ at a rate of 5℃ / min under the continuous protection of nitrogen gas at a flow rate of 100 mL / min. Heat it at this temperature for 2 h and then cool it naturally to room temperature to obtain the high-temperature carbonization product. ③ The high-temperature carbonization product prepared in step ② is washed three times with 0.5 mol / L dilute hydrochloric acid to remove impurities, and then washed three times with water to remove hydrochloric acid. It is then placed in an oven and dried at 80℃ for 12 h to obtain phosphorus-doped biomass porous carbon.

[0019] Example 2: This example proposes a method for preparing nutrient soil using slag, mud, and silt, specifically including the following steps: S1. Use a crusher to crush the slag and obtain slag particles with a particle size of 15 mm. S2. Pre-treat the mud and sludge by using a slag and sand removal device to remove impurities from the mud and sludge respectively, and then further dewater them by centrifugal thickening device. The moisture content of the dewatered mud and sludge is 30%. S3. Add 40 parts by weight of slag particles, 30 parts by weight of dewatered slurry and 20 parts by weight of dewatered sludge to a mixer and mix evenly to obtain a slag-slurry-sludge mixture. S4. Add 4 parts by weight of phosphorus-doped biomass porous carbon, 1 part by weight of sodium tripolyphosphate, 10 parts by weight of bagasse, 2 parts by weight of sodium alginate, 2 parts by weight of wood ash, 0.7 parts by weight of boric acid, and 0.8 parts by weight of Tween 80 to the mixture prepared in step S3 to obtain mixed soil. S5. Ferment the mixed soil material using a mixed pile fermentation method, adjust the humidity to 40%, seal it, and ferment at 54℃ for 7 days. S6. Adjust the humidity of the mixed soil after fermentation in step S5 to 50%, and keep it at 60℃ for secondary fermentation for 4 days. During this period, turn the mixed soil over every 24 hours to ensure oxygen supply. S7. After the secondary fermentation in step S6, the mixed soil is dried at 70°C until the moisture content is 10%, and then sieved through a 100-mesh sieve to obtain nutrient soil.

[0020] The method for preparing phosphorus-doped biomass porous carbon includes the following steps: ① Wash the corn stalks with water, dry them in an oven at 100℃ for 12 hours, and then grind them in a pulverizer to obtain biomass powder with a diameter of 2±0.5 mm. ② Weigh 4 g of the biomass powder prepared in step ① and mix it evenly with 1 g of potassium carbonate and 1 g of dipotassium hydrogen phosphate. Place it in the constant temperature zone of a tube furnace and heat it to 800℃ at a rate of 5℃ / min under the continuous protection of nitrogen gas at a flow rate of 100 mL / min. Heat it at this temperature for 3 h and then cool it naturally to room temperature to obtain the high-temperature carbonization product. ③ The high-temperature carbonization product prepared in step ② is washed three times with 0.5 mol / L dilute hydrochloric acid to remove impurities, and then washed three times with water to remove hydrochloric acid. It is then placed in an oven and dried at 100℃ for 12 h to obtain phosphorus-doped biomass porous carbon.

[0021] Example 3: This example proposes a method for preparing nutrient soil using slag, mud, and silt, specifically including the following steps: S1. Use a crusher to crush the slag and obtain slag particles with a particle size of 20 mm. S2. Pre-treat the mud and sludge by using a slag and sand removal device to remove impurities from the mud and sludge respectively, and then further dewater them by centrifugal thickening device. The moisture content of the dewatered mud and sludge is 25%. S3. Add 50 parts by weight of slag particles, 25 parts by weight of dewatered slurry and 26 parts by weight of dewatered sludge to a mixer and mix evenly to obtain a slag-slurry-sludge mixture. S4. Add 5 parts by weight of phosphorus-doped biomass porous carbon, 3 parts by weight of sodium tripolyphosphate, 15 parts by weight of bagasse, 3 parts by weight of sodium alginate, 5 parts by weight of wood ash, 1 part by weight of boric acid, and 0.8 parts by weight of alkyl glycoside APG0810 to the mixture prepared in step S3 to obtain mixed soil. S5. Ferment the mixed soil material using a mixed pile fermentation method, adjust the humidity to 50%, seal it, and ferment at 60℃ for 6 days. S6. Adjust the humidity of the mixed soil after fermentation in step S5 to 60%, and keep it at 50℃ for secondary fermentation for 5 days. During this period, turn the mixed soil over every 24 hours to ensure oxygen supply. S7. After the secondary fermentation in step S6, the mixed soil is dried at 70°C until the moisture content is 10%, and then sieved through a 100-mesh sieve to obtain nutrient soil.

[0022] The method for preparing phosphorus-doped biomass porous carbon includes the following steps: ① Wash the rice straw with water, put it in an oven and dry it at 90℃ for 12 hours, then put it in a pulverizer to pulverize it to obtain biomass powder with a diameter of 2±0.5 mm; ② Weigh 4.5 g of the biomass powder prepared in step ① and mix it evenly with 1.5 g of potassium carbonate and 1.5 g of dipotassium hydrogen phosphate. Place it in the constant temperature zone of a tube furnace and heat it to 840°C at a rate of 5°C / min under the continuous protection of nitrogen gas at a flow rate of 100 mL / min. Heat it at this temperature for 4 h and then cool it naturally to room temperature to obtain the high-temperature carbonization product. ③ The high-temperature carbonization product prepared in step ② is washed three times with 0.5 mol / L dilute hydrochloric acid to remove impurities, and then washed three times with water to remove hydrochloric acid. It is then placed in an oven and dried at 90℃ for 12 h to obtain phosphorus-doped biomass porous carbon.

[0023] Comparative Example 1: This comparative example proposes a method for preparing nutrient soil using slag, mud and silt. The only difference between this method and Example 1 is that phosphorus-doped biomass porous carbon is not added. All other components, component contents and experimental steps are the same as in Example 1.

[0024] Comparative Example 2: This comparative example proposes a method for preparing nutrient soil using slag, mud and silt. The only difference between this method and Example 1 is that sodium alginate is not added. All other components, component contents and experimental steps are the same as in Example 1.

[0025] Experimental Example 1: The microstructure of the phosphorus-doped biomass porous carbon prepared in Example 1 was observed using a scanning electron microscope.

[0026] Figure 1 The image shows a scanning electron microscope (SEM) image of the phosphorus-doped biomass porous carbon prepared in Example 1. As shown in the figure, the prepared porous carbon material has a uniform pore size of approximately 200 nm, which is beneficial for improving its adsorption performance, indicating the successful preparation of phosphorus-doped biomass porous carbon.

[0027] Experiment Example 2: Performance Test of Nutrient Soil Water absorption rate: Take 20 g of the nutrient soil prepared in Examples 1-3 and Comparative Examples 1-2 and place it in a funnel. Place a filter paper at the bottom of the funnel, slowly add water, record the amount of water remaining in the soil sample after infiltration, and calculate the water absorption rate. Water retention time: After testing the water absorption rate, the nutrient soil was spread evenly in a 120 mL flat container, placed in natural air, and the drying time was recorded. Loose density: The nutrient soil prepared in Examples 1-3 and Comparative Examples 1-2 was respectively packed into 1 m³ of soil. 3 In the container, avoid vibration, and gently scrape off the excess nutrient soil with a glass plate until it is flush with the mouth of the measuring cylinder. Loose density = soil mass / container volume; Looseness: The looseness of the nutrient soil prepared in Examples 1-3 and Comparative Examples 1-2 was evaluated by touch. The test results are shown in Table 1.

[0028] Table 1 Performance Tests of Nutrient Soil

[0029] As shown in Table 1, the nutrient soils prepared in Examples 1-3 have high water absorption rates and long water retention times. This is because the added phosphorus-doped biomass porous carbon and sodium alginate can both improve the soil's water retention capacity and reduce water loss. The nutrient soils prepared in Examples 1-3 and Comparative Example 2 have low soil density and moderate looseness because they contain porous phosphorus-doped biomass porous carbon materials, resulting in a loose structure and good aeration.

[0030] Experiment 3: The application effect test was carried out using the nutrient soil prepared in Examples 1-3 and Comparative Examples 1-2. Ordinary soil was set as the control group, and pansy was selected as the test variety. Pansy seedlings were planted 8 cm below the surface of the nutrient soil and placed under the same environmental conditions (temperature 25±2℃, light 12 hours / day, relative humidity 60-70%). They were watered with the same amount for 7 days, and then watered once every 7 days after 7 days. All plants were harvested after 5 weeks, and the height of the plants, stem diameter and root condition were recorded. The results are shown in Table 2.

[0031] Table 2 Application Effect Test

[0032] As shown in Table 2, the nutrient soil prepared in Examples 1-3 had the best effect on the growth of pansy seedlings, which was better than that in Comparative Examples 1-2. The control group had the worst effect, indicating that the nutrient soil prepared by this method has the advantages of rich nutrients and long-lasting fertility, which can significantly promote plant growth. At the same time, it realizes the resource utilization of waste and has significant economic and environmental benefits.

[0033] The present invention and its embodiments have been described above. This description is not restrictive, and practical applications are not limited thereto. In conclusion, if those skilled in the art are inspired by this description and, without departing from the spirit of the invention, design similar methods and embodiments to this technical solution without creative effort, all such designs should fall within the protection scope of the present invention.

Claims

1. A method for preparing nutrient soil using slag, mud, and silt, characterized in that, Specifically, the following steps are included: S1. Crush the slag to obtain slag particles; S2. Pre-treat the mud and sludge to remove impurities from the mud and sludge respectively, and then further centrifuge and dewater to obtain dewatered mud and dewatered sludge. S3. Add 40-50 parts by weight of slag particles, 20-30 parts by weight of dewatered slurry and 20-30 parts by weight of dewatered sludge to a mixer and mix evenly to obtain a slag-slurry-sludge mixture. S4. Add 2-5 parts by weight of phosphorus-doped biomass porous carbon, 1-3 parts by weight of sodium tripolyphosphate, 10-15 parts by weight of bagasse, 2-4 parts by weight of sodium alginate, 2-5 parts by weight of wood ash, 0.5-1 parts by weight of boric acid, and 0.5-1 parts by weight of nonionic surfactant to the mixture prepared in step S3 to obtain mixed soil material. S5. Ferment the mixed soil material using a mixed pile fermentation method; S6. The mixed soil material after fermentation in step S5 is fermented a second time. S7. After drying the mixed soil material after the secondary fermentation in step S6, sieve it to obtain nutrient soil.

2. The method for preparing nutrient soil using slag, mud, and silt according to claim 1, characterized in that, The method for preparing phosphorus-doped biomass porous carbon includes the following steps: ① Clean the biomass waste, dry and crush it to obtain biomass powder; ② Weigh the biomass powder prepared in step ①, mix it evenly with potassium carbonate and dipotassium hydrogen phosphate, and pyrolyze it at high temperature to obtain high-temperature carbonization products; ③ The high-temperature carbonization product prepared in step ② is washed with dilute hydrochloric acid to remove impurities, then washed with water and dried to obtain phosphorus-doped biomass porous carbon.

3. The method for preparing nutrient soil using slag, mud, and silt according to claim 2, characterized in that, In step ①, the biomass waste can be any one of sugarcane bagasse, corn stalks, or rice straw.

4. The method for preparing nutrient soil using slag, mud, and silt according to claim 3, characterized in that, The nonionic surfactant is any one of Tween 20, Tween 80, or alkyl glycoside APG0810.

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