Fly ash artificial soil and preparation method thereof

Abstract

The invention discloses fly ash artificial soil and a preparation method thereof, and relates to the technical field of artificial soil, the key point of the technical scheme is that the preparation method comprises the following steps: step 1, acid treatment: taking fly ash, adding acid, mixing with the fly ash, and stirring to obtain acid-treated fly ash with the pH value of 7-7.5; step 2, washing and desalting: putting the acid-treated fly ash into water, stirring for 30-60 minutes, standing for 3-5 hours, and filtering to remove supernate, so as to obtain washed fly ash; step 3, pretreating cattle and sheep manure; step 4, chelating humic acid; step 5, fermentation treatment: mixing the washed fly ash, the decomposed cattle and sheep manure and the humic acid iron chelate, and adding a fermentation inoculant for fermentation to obtain an artificial soil blank; and 6, post-treatment: carrying out particle size grading screening on the artificial soil blank, adding a pH buffer agent and / or carrying out embedding synergism to obtain the fly ash-based artificial soil. The fly ash artificial soil is prepared by combining industrial solid waste fly ash with agricultural waste, and the effects of no pollution and effective improvement of the soil environment are achieved.

Description

Technical Field

[0001] This invention relates to the field of artificial soil technology, and more specifically to a fly ash artificial soil and its preparation method. Background Technology

[0002] Soil is the essential material basis and resource for plant survival; the cultivation of potted flowers and the greening of garden landscapes both rely on soil. Currently, land resources are becoming increasingly strained due to natural forces and urbanization, leading to continuous degradation of soil quality in some areas. Fly ash shares a similar chemical composition with soil, primarily consisting of SiO2 and Al2O3, and is rich in essential micronutrients necessary for plant growth. This gives it a natural advantage in preparing soil amendment materials. Therefore, current technologies often use fly ash to prepare artificial planting soil, which not only improves soil quality but also addresses the problems of industrial solid waste fly ash occupying large amounts of land, polluting the environment, and harming human health.

[0003] Chinese Patent Publication No. CN107556132A discloses a method for producing fly ash-based artificial soil. The method includes the following steps: Step 1, mixing fly ash with acid evenly to obtain a first mixture; Step 2, mixing the first mixture obtained in Step 1 with raw cow and sheep manure, slag soil, and humic acid evenly to obtain a second mixture; Step 3, adding water and fermentation agent to the second mixture obtained in Step 2 for composting and fermentation to obtain fly ash-based artificial soil.

[0004] However, the method for producing fly ash-based artificial soil involves only simple mixing of materials when preparing fly ash, which results in poor bonding between the components. This makes it impossible to fully express the trace elements of fly ash in the soil and fails to effectively avoid potential environmental pollution problems, thus requiring improvement. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method for manufacturing fly ash artificial soil, which has the effects of being pollution-free and effectively improving the soil environment.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for manufacturing fly ash artificial soil includes the following steps: Step 1, Acid Treatment: Take fly ash and measure its pH to obtain the pH value. Calculate the required amount of acid based on the neutralization calculation. Mix 60-70% of the required amount of low-concentration acid with fly ash and stir once, then let it stand. Add the remaining amount of high-concentration acid and mix with fly ash a second time to obtain acid-treated fly ash with a pH of 7-7.5. Step 2, water washing and desalination: Add the acid-treated fly ash into water and stir for 30-60 minutes. Control the mass mixing ratio of water to acid-treated fly ash to be 1-2:1. After standing for 3-5 hours, filter to remove the supernatant to obtain water-washed fly ash. Step 3, Pre-treatment of cow and sheep manure: The raw cow and sheep manure is piled up separately for composting to obtain composted cow and sheep manure; Step 4, Humic acid chelation: Mix humic acid with ferric sulfate solution and stir to form humic acid-ferric sulfate chelate; Step 5, Fermentation treatment: Mix the washed fly ash, decomposed cow and sheep manure and humic acid iron chelate to form a mixture. Add fermentation agent to the mixture. Turn the pile when the temperature is controlled above 65℃ and control the ambient temperature below 15℃. Maintain the temperature at 50-60℃ and the fermentation cycle is 10-12 days to obtain artificial soil material. Step 6, Post-processing: The artificial soil embryo is subjected to particle size classification and sieving, and pH buffer and / or encapsulation enhancement are added to obtain fly ash-based artificial soil.

[0007] Preferably, in step 1, the low-concentration acid is 10% phosphoric acid by mass, and the high-concentration acid is 20% phosphoric acid by mass; the first stirring treatment is a stirring treatment of 30 minutes, and the standing time is 2 hours; the second stirring treatment is a stirring treatment of 1 hour.

[0008] Preferably, step 2 is repeated 1-2 times, and the EC value of the washed fly ash is less than 1.5 mS / cm.

[0009] Preferably, in step 3, the composting process involves adding 5% by weight of straw and 0.5% of fermentation agent to the raw cattle and sheep manure, piling it to a height of 1.2-1.5m, covering it with a moisture-retaining film, and turning it over at least once a day for 7-10 days to obtain composted cattle and sheep manure.

[0010] Preferably, in step 4, the mass concentration of the ferric sulfate solution is 10%, and the amount added is 0.5% of the mass of the humic acid.

[0011] Preferably, in step 5, the fermentation agent comprises actinomycetes, yeasts and Bacillus subtilis in a weight ratio of 1-1.1:1-1.1:2, and the amount of the fermentation agent added is 0.3-0.5% of the mass of the mixture.

[0012] Preferably, in step 6, the particle size grading sieving is performed using 10-mesh and 30-mesh sieves; the pH buffer is peat moss and the amount added is 0.5-1% of the mass of the fly ash-based artificial soil; the encapsulation enhancement is achieved by adding 2-3% of urea or diammonium phosphate based on the mass of the fly ash-based artificial soil.

[0013] A second objective of this invention is to provide a fly ash artificial soil, comprising a fly ash artificial soil prepared by the method described above.

[0014] As shown in the above scheme, this application provides a fly ash artificial soil and its preparation method. This method uses industrial solid waste fly ash as the main raw material, co-producing it with agricultural waste, thereby reducing solid waste accumulation pollution and improving the ecological environment while enhancing the economic value of fly ash. Simultaneously, this fly ash artificial soil is prepared through acid treatment, water washing desalination, and chelation treatment, effectively reducing the alkalinity of fly ash and controlling salt content and heavy metal bioavailability. This allows the fly ash artificial soil to meet planting safety standards and be suitable for landscaping and agricultural planting. This fly ash artificial soil has environmental protection and soil environment improvement effects. Detailed Implementation

[0015] To make the technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0016] The following will provide a detailed description of a fly ash artificial soil and its manufacturing method, which are based on this application.

[0017] A method for manufacturing fly ash artificial soil includes the following steps: Step 1, Acid Treatment: Take fly ash and measure its pH to obtain the required amount of acid based on the neutralization calculation. Mix 60-70% of the required amount of 10% phosphoric acid with fly ash and stir for 30 minutes, then let it stand for 2 hours. Add the remaining 20% ​​phosphoric acid and mix with fly ash for 1 hour to obtain acid-treated fly ash with a pH of 7-7.5. Step 2, water washing and desalination: Add the acid-treated fly ash to water and stir for 30-60 minutes. Control the mass mixing ratio of water to acid-treated fly ash to be 1-2:1. After standing for 3-5 hours, filter to remove the supernatant. Repeat step 2 1-2 times to obtain water-washed fly ash with an EC value of less than 1.5 mS / cm. Step 3, Pretreatment of cattle and sheep manure: The raw cattle and sheep manure is piled up separately for composting. The composting process involves adding 5% straw and 0.5% Bacillus subtilis by weight as fermentation agents to the raw cattle and sheep manure. After piling to a height of 1.2-1.5m, covering with a moisture-retaining film, and turning the pile at least once a day for 7-10 days, the composted cattle and sheep manure is obtained after mixing. Step 4, Humic acid chelation: Humic acid is mixed and stirred with a 10% ferric sulfate solution, and the amount of ferric sulfate solution added is controlled to be 0.5% of the mass of the humic acid to form ferric humate chelate. Step 5, Fermentation Treatment: Mix washed fly ash, well-rotted cow and sheep manure, and humic acid iron chelate to form a mixture. Add fermentation agents to the mixture. The fermentation agents include actinomycetes, yeasts, and Bacillus subtilis in a weight ratio of 1-1.1:1-1.1:2, and the amount of fermentation agents added is 0.3-0.5% of the mass of the mixture. Turn the pile when the temperature is controlled above 65℃, and control the ambient temperature below 15℃. Maintain the temperature at 50-60℃. The fermentation cycle is 10-12 days to obtain artificial soil material. Step 6, Post-processing: The artificial soil embryo is subjected to particle size classification and sieving, and pH buffer and / or encapsulation enhancement are added to obtain fly ash-based artificial soil.

[0018] The particle size classification and sieving are performed using 10-mesh and 30-mesh sieves. The pH buffer is peat moss, and the amount added is 0.5-1% of the mass of fly ash-based artificial soil. The encapsulation enhancement is achieved by adding 2-3% urea or diammonium phosphate based on the mass of fly ash-based artificial soil.

[0019] A fly ash artificial soil is prepared by the method described above for manufacturing fly ash artificial soil. Example

[0020] A method for manufacturing fly ash artificial soil includes the following steps: Step 1, Acid Treatment: Take fly ash and measure its pH to obtain the required amount of acid based on the neutralization calculation. Mix 60% of the required amount of 10% phosphoric acid with fly ash and stir for 30 minutes, then let it stand for 2 hours. Add the remaining 20% ​​phosphoric acid and mix with fly ash for 1 hour to obtain acid-treated fly ash with a pH of 7.5. Step 2, water washing and desalination: Add acid-treated fly ash to water and stir for 30 minutes. Control the mass mixing ratio of water to acid-treated fly ash to be 1:1. After standing for 3 hours, filter to remove the supernatant. Repeat step 2 once to obtain water-washed fly ash with an EC value of less than 1.5 mS / cm. Step 3, Pretreatment of cattle and sheep manure: Raw cattle and sheep manure is piled up separately for composting treatment. The composting treatment involves adding 5% straw and 0.5% Bacillus subtilis by weight as fermentation agents to the raw cattle and sheep manure. After piling up to a height of 1.2m, covering with a moisture-retaining film, and turning the pile at least once a day for 7 days, the composted cattle and sheep manure is obtained after mixing. Step 4, Humic acid chelation: Humic acid is mixed and stirred with a 10% ferric sulfate solution, and the amount of ferric sulfate solution added is controlled to be 0.5% of the mass of the humic acid to form ferric humate chelate. Step 5, Fermentation treatment: Washed fly ash, decomposed cow and sheep manure and humic acid iron chelate are mixed to form a mixture. Fermentation agents are added to the mixture. The fermentation agents include actinomycetes, yeast and Bacillus subtilis in a weight ratio of 1:1:2, and the amount of fermentation agents added is 0.3% of the mass of the mixture. The mixture is turned over when the temperature is controlled above 65℃, and the ambient temperature is controlled below 15℃. The temperature is maintained at 50-54℃, and the fermentation cycle is 10 days to obtain artificial soil material. Step 6, Post-processing: The artificial soil embryo is subjected to particle size classification and sieving, pH buffer is added and encapsulation is performed to obtain fly ash-based artificial soil.

[0021] The particle size grading and sieving were performed using 10-mesh and 30-mesh sieves. The pH buffer was peat moss, added at 0.5% of the mass of the fly ash-based artificial soil. The encapsulation enhancement was achieved by adding urea at 2% of the mass of the fly ash-based artificial soil.

[0022] A fly ash artificial soil is prepared by the method described above for manufacturing fly ash artificial soil. Example

[0023] A method for manufacturing fly ash artificial soil includes the following steps: Step 1, Acid Treatment: Take fly ash and measure its pH to obtain the required amount of acid based on the neutralization calculation. Mix 65% of the required amount of 10% phosphoric acid with fly ash and stir for 30 minutes, then let it stand for 2 hours. Add the remaining 20% ​​phosphoric acid and mix with fly ash for 1 hour to obtain acid-treated fly ash with a pH of 7.2. Step 2, water washing and desalination: Add acid-treated fly ash to water and stir for 45 minutes. Control the mass mixing ratio of water to acid-treated fly ash to be 1.5:1. After standing for 4 hours, filter to remove the supernatant. Repeat step 2 twice to obtain water-washed fly ash with an EC value of less than 1.5 mS / cm. Step 3, Pretreatment of cattle and sheep manure: Raw cattle and sheep manure is piled up separately for composting treatment. The composting treatment involves adding 5% straw and 0.5% Bacillus subtilis by weight as fermentation agents to the raw cattle and sheep manure. After piling up to a height of 1.35m, covering with a moisture-retaining film, and turning the pile at least once a day for 8 days, the composted cattle and sheep manure is obtained after mixing. Step 4, Humic acid chelation: Humic acid is mixed and stirred with a 10% ferric sulfate solution, and the amount of ferric sulfate solution added is controlled to be 0.5% of the mass of the humic acid to form ferric humate chelate. Step 5, Fermentation treatment: Washed fly ash, decomposed cow and sheep manure and humic acid iron chelate are mixed to form a mixture. Fermentation agents are added to the mixture. The fermentation agents include actinomycetes, yeast and Bacillus subtilis in a weight ratio of 1:1.1:2, and the amount of fermentation agents added is 0.4% of the mass of the mixture. The pile is turned when the temperature is controlled above 65℃, and the ambient temperature is controlled below 15℃. The temperature is maintained at 53-57℃, and the fermentation cycle is 11 days to obtain artificial soil material. Step 6, Post-processing: The artificial soil embryo is subjected to particle size classification and sieving, pH buffer is added and encapsulation is performed to obtain fly ash-based artificial soil.

[0024] The particle size classification and sieving were performed using 10-mesh and 30-mesh sieves. The pH buffer was peat moss, added at 0.7% of the mass of fly ash-based artificial soil. The encapsulation enhancement was achieved by adding 2.5% diammonium phosphate based on the mass of fly ash-based artificial soil.

[0025] A fly ash artificial soil is prepared by the method described above for manufacturing fly ash artificial soil. Example

[0026] A method for manufacturing fly ash artificial soil includes the following steps: Step 1, Acid Treatment: Take fly ash and measure its pH to obtain the required amount of acid based on the neutralization calculation. Mix 70% of the required amount of 10% phosphoric acid with fly ash and stir for 30 minutes, then let it stand for 2 hours. Add the remaining 20% ​​phosphoric acid and mix with fly ash for 1 hour to obtain acid-treated fly ash with a pH of 7.1. Step 2, water washing and desalination: Add acid-treated fly ash to water and stir for 60 minutes. Control the mass mixing ratio of water to acid-treated fly ash to be 2:1. After standing for 5 hours, filter to remove the supernatant. Repeat step 2 twice to obtain water-washed fly ash with an EC value of less than 1.5 mS / cm. Step 3, Pretreatment of cattle and sheep manure: Raw cattle and sheep manure is piled up separately for composting treatment. The composting treatment involves adding 5% straw and 0.5% Bacillus as fermentation agents to the raw cattle and sheep manure. After piling up to a height of 1.5m, covering with a moisture-retaining film, and turning the pile at least once a day for 10 days, the composted cattle and sheep manure is obtained after mixing. Step 4, Humic acid chelation: Humic acid is mixed and stirred with a 10% ferric sulfate solution, and the amount of ferric sulfate solution added is controlled to be 0.5% of the mass of the humic acid to form ferric humate chelate. Step 5, Fermentation treatment: Washed fly ash, decomposed cow and sheep manure and humic acid iron chelate are mixed to form a mixture. Fermentation agents are added to the mixture. The fermentation agents include actinomycetes, yeast and Bacillus subtilis in a weight ratio of 1.1:1.1:2, and the amount of fermentation agents added is 0.5% of the mass of the mixture. The pile is turned when the temperature is controlled above 65℃, and the ambient temperature is controlled below 15℃. The temperature is maintained at 56-60℃, and the fermentation cycle is 12 days to obtain artificial soil material. Step 6, Post-processing: The artificial soil embryo is subjected to particle size classification and screening and pH buffer is added to obtain fly ash-based artificial soil.

[0027] The particle size grading and screening were performed using 10-mesh and 30-mesh sieves. The pH buffer was peat moss, and its addition amount was 1% of the mass of the fly ash-based artificial soil.

[0028] A fly ash artificial soil is prepared by the method described above for manufacturing fly ash artificial soil.

[0029] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the raw cattle and sheep manure in Comparative Example 1 was not pretreated.

[0030] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the fly ash in Comparative Example 2 was treated with a low-concentration acid with a sufficient amount of acid.

[0031] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the fly ash in Comparative Example 3 was not acid-treated.

[0032] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the humic acid in Comparative Example 4 was not subjected to humic acid chelation treatment.

[0033] Performance testing: 1. Determination of heavy metal leaching: Take 100g of fly ash artificial soil as a sample, add 1L of deionized water, shake at 25℃ for 8h, and let stand for 16h; filter the leachate and use inductively coupled plasma mass spectrometry (ICP-MS) to determine the concentration of heavy metals in the leachate, and determine whether it exceeds the limit according to the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard" (GB 15618-2018); 2. EC value stability determination: Take 50g of fly ash artificial soil as a sample, add 250mL of deionized water, stir for 30min and let stand for 1h, and measure the EC value of the supernatant. 3. Soil physical property improvement test: The saline-alkali soil to be improved and fly ash artificial soil were mixed at a mass ratio of 1:1, and the unimproved saline-alkali soil was used as a control. The bulk density and total porosity of the mixed soil were determined by the ring cutter method according to "Determination of Soil Physical Properties" NY / T 1121.4, and the maximum water holding capacity of the soil was determined by the tensiometer method.

[0034] 4. Plant growth verification experiment: Fly ash artificial soil, mixed soil made by mixing fly ash artificial soil and saline-alkali soil at a mass ratio of 1:1, and saline-alkali soil were tested and compared in separate groups. Each group was planted with 10 seedlings, and the light and watering conditions were kept consistent. After 30 days of cultivation, the plant height, fresh weight, and leaf chlorophyll content were measured. After harvest, the amount of heavy metal accumulation in the plants was measured to assess safety.

[0035] The performance test results are shown in Table 1 below.

[0036] Table 1 Performance Test Results

[0037] As can be seen from Table 1 above, the fly ash artificial soil in this application embodiment performs excellently in terms of environmental safety and soil improvement effect. Among them, embodiment 2 has the best effect due to parameter optimization. The reason is that acid treatment, full composting, and humic acid chelation are the core processes to ensure the safety performance of fly ash artificial soil.

[0038] In summary, this application provides a fly ash artificial soil and its preparation method. This method uses industrial solid waste fly ash as the main raw material, co-producing it with agricultural waste, thereby reducing solid waste accumulation pollution and improving the ecological environment while enhancing the economic value of fly ash. Furthermore, this fly ash artificial soil is prepared through acid treatment, water washing desalination, and chelation treatment, effectively reducing the alkalinity of fly ash and controlling salt content and heavy metal bioavailability. This allows the fly ash artificial soil to meet planting safety standards and be suitable for landscaping and agricultural applications. This fly ash artificial soil has environmental protection and soil environment improvement effects.

[0039] The terms “first,” “second,” “third,” “fourth,” etc., used in this application (if applicable) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, or apparatus that includes a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, or apparatus.

[0040] It should be noted that the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0041] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for manufacturing fly ash artificial soil, characterized in that, Includes the following steps: Step 1, Acid Treatment: Take fly ash and measure its pH to obtain the pH value. Calculate the required amount of acid based on the neutralization calculation. Mix 60-70% of the required amount of low-concentration acid with fly ash and stir once, then let it stand. Add the remaining amount of high-concentration acid and mix with fly ash a second time to obtain acid-treated fly ash with a pH of 7-7.

5. Step 2, water washing and desalination: Add the acid-treated fly ash into water and stir for 30-60 minutes. Control the mass mixing ratio of water to acid-treated fly ash to be 1-2:

1. After standing for 3-5 hours, filter to remove the supernatant to obtain water-washed fly ash. Step 3, Pre-treatment of cow and sheep manure: The raw cow and sheep manure is piled up separately for composting to obtain composted cow and sheep manure; Step 4, Humic acid chelation: Mix humic acid with ferric sulfate solution and stir to form humic acid-ferric sulfate chelate; Step 5, Fermentation treatment: Mix the washed fly ash, decomposed cow and sheep manure and humic acid iron chelate to form a mixture. Add fermentation agent to the mixture. Turn the pile when the temperature is controlled above 65℃ and control the ambient temperature below 15℃. Maintain the temperature at 50-60℃ and the fermentation cycle is 10-12 days to obtain artificial soil material. Step 6, Post-processing: The artificial soil embryo is subjected to particle size classification and sieving, and pH buffer and / or encapsulation enhancement are added to obtain fly ash-based artificial soil.

2. The method for manufacturing fly ash artificial soil according to claim 1, characterized in that: In step 1, the low-concentration acid is 10% phosphoric acid by mass, and the high-concentration acid is 20% phosphoric acid by mass; the first stirring treatment is a stirring treatment of 30 minutes, and the standing time is 2 hours; the second stirring treatment is a stirring treatment of 1 hour.

3. The method for manufacturing fly ash artificial soil according to claim 1, characterized in that: The operation of step 2 is repeated 1-2 times, and the EC value of the washed fly ash is less than 1.5 mS / cm.

4. The method for manufacturing fly ash artificial soil according to claim 1, characterized in that: In step 3, the composting process involves adding 5% by weight of straw and 0.5% of fermentation agent to the raw cattle and sheep manure, piling it up to a height of 1.2-1.5m, covering it with a moisture-retaining film, and turning it over at least once a day for 7-10 days to obtain composted cattle and sheep manure.

5. The method for manufacturing fly ash artificial soil according to claim 1, characterized in that: In step 4, the ferric sulfate solution has a mass concentration of 10%, and the amount added is 0.5% of the mass of the humic acid.

6. The method for manufacturing fly ash artificial soil according to claim 1, characterized in that: In step 5, the fermentation agent includes actinomycetes, yeasts and Bacillus subtilis in a weight ratio of 1-1.1:1-1.1:2, and the amount of the fermentation agent added is 0.3-0.5% of the mass of the mixture.

7. The method for manufacturing fly ash artificial soil according to claim 1, characterized in that: In step 6, the particle size classification screening is performed using 10-mesh and 30-mesh sieves; the pH buffer is peat soil and the amount added is 0.5-1% of the mass of the fly ash-based artificial soil; the encapsulation enhancement is achieved by adding 2-3% of urea or diammonium phosphate according to the mass of the fly ash-based artificial soil.

8. A fly ash-based artificial soil, characterized in that: This includes preparation using the method for manufacturing fly ash artificial soil as described in any one of claims 1-7.

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