Preparation method of efficient organic fertilizer based on sheep manure

Abstract

The invention discloses a method for preparing an efficient organic fertilizer based on sheep manure. The method comprises two steps of catalytic conversion of organic matters and compounding of the organic fertilizer. Catalytic conversion of organic matters: crushing sheep manure, adding potassium hydroxide and iron oxyhydroxide, adding water, uniformly stirring and mixing, and then performing hydrothermal treatment on the mixture to obtain slurry; compounding an organic fertilizer: filtering the slurry to respectively obtain filtrate and filter residues, adding acid into the filtrate, and standing to obtain humic acid precipitate; washing filter residues with water; and drying, crushing and mixing the humic acid precipitate and the washed filter residue to finally obtain the humic acid high-efficiency organic fertilizer. According to the method, organic matters in sheep manure are used for producing the efficient organic fertilizer, so that the resource conversion of biomass solid wastes is realized, the environmental protection benefit is remarkably improved, the quality and yield of crops are improved, the use of traditional chemical fertilizers is reduced, and the method shows sustainability and wide application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste treatment, and in particular to a method for preparing a high-efficiency organic fertilizer based on sheep manure. Background Art

[0002] As a common livestock and poultry manure, sheep manure is rich in organic matter and nutrients and has the potential to be converted into high-efficiency organic fertilizer. Sheep manure composting is a common treatment method that converts manure into organic fertilizer through aerobic fermentation. According to the different composting facilities and processes, it can be divided into traditional static composting, dynamic turning composting and static ventilation composting. These composting treatments have the disadvantages of easy loss of fertilizer and long treatment cycle. In addition, the traditional stacking method occupies a lot of land and requires long-term maintenance costs. Sheep manure is mainly cellulose, hemicellulose and lignin, rich in carbon, hydrogen, oxygen and nitrogen elements, and is a very suitable raw material for fertilizer products. Therefore, the development of efficient and environmentally friendly organic fertilizers has become a research hotspot.

[0003] In the agricultural field, humic acid can improve soil, increase fertilizer utilization, stimulate crop growth and improve stress resistance. In the environmental field, humic acid can complex with heavy metal ions to achieve the effect of soil remediation. Humic acid also performs well in sewage treatment. The key to extracting humic acid from sheep manure is to improve the extraction rate while taking into account environmental friendliness. Obviously, the traditional composting form has low extraction efficiency and takes a long time, so a rapid humification technology is needed. Since the components of sheep manure are large molecular organic matter, it can be pyrolyzed into small molecular organic matter through catalytic conversion technology to obtain humic acid. Therefore, efficient catalytic conversion technology is a key factor. Summary of the invention

[0004] Purpose of the invention: The present invention aims to provide a method for preparing a high-efficiency organic fertilizer based on sheep manure, which utilizes components such as lignocellulose in sheep manure to prepare a humic acid organic fertilizer with high fertility. It is a low-cost and rapid method for converting lignocellulose in sheep manure into highly active humic acid.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] A method for preparing high-efficiency organic fertilizer based on sheep manure comprises the following steps:

[0007] (1) crushing sheep manure, adding a certain proportion of potassium hydroxide and ferric oxyhydroxide and mixing;

[0008] (2) adding water to the mixed material and stirring it evenly, performing a hydrothermal reaction under high temperature and high pressure conditions for a certain period of time, and obtaining a slurry through catalytic conversion;

[0009] (3) Centrifuge the slurry after cooling, and then filter it to obtain the filtrate and the filter residue;

[0010] (4) Add a certain amount of acid solution to the filtrate to adjust the pH value, let the target product settle, and then filter, wash, and dry the precipitate to obtain humic acid;

[0011] (5) Wash the filter residue with water and then dry it to obtain the hydrothermal carbon matrix.

[0012] (6) Grind and mix the humic acid in step (4) and the hydrothermal carbon matrix in step (5) to obtain the high-efficiency organic fertilizer of humic acid.

[0013] Furthermore, the mass ratio of the lake sheep manure to potassium hydroxide in step (1) is 10:1 to 2, the mass ratio of the sheep manure to iron hydroxide is 10000:1 to 5, and the particle size is 500 to 700 mesh.

[0014] Furthermore, the mass ratio of the sheep manure to potassium hydroxide in step (1) is the key influencing factor. In the single-factor experiments with mass ratios of 10:1, 10:1.5, and 10:2, according to the final mass of the humic acid obtained in step (4), the preferred ratio is 10:1.5.

[0015] Furthermore, in step (2), the ratio of deionized water to the mixed materials is 2:1, the stirring time is 20 to 30 minutes, the hydrothermal temperature is 250 °C, and the heat preservation time is 2 hours.

[0016] Furthermore, in step (3), a centrifuge is used to centrifuge the slurry, and then a vacuum filter is used for filtration.

[0017] Furthermore, in step (4), phosphoric acid or hydrochloric acid is used to adjust the pH of the filtrate to below 2, and the precipitation process needs to be placed in a refrigerated environment for 10 to 12 hours; then filter, wash, and dry to finally obtain humic acid.

[0018] Furthermore, in step (5), the washing operation uses a vacuum filter and is washed with deionized water; then it is dried in an oven at 60 °C for 10 to 12 hours.

[0019] Furthermore, in step (6), the humic acid and the hydrothermal carbon organic matter are mixed and ground in a mortar, with a ratio of 1:3 to 4, and the grinding time is 20 to 30 minutes, and finally the solid powder of the high-efficiency organic fertilizer of humic acid is obtained.

[0020] Furthermore, the final product is the high-efficiency organic fertilizer of humic acid, with a humic acid content greater than 20%, an organic matter content greater than 60%, and the product is rich in essential elements for crops such as nitrogen, phosphorus, and potassium.

[0021] The preparation technical principle of the high-efficiency organic fertilizer based on sheep manure in the present invention:

[0022] In agricultural production, the use of organic fertilizers is of great significance for improving soil fertility and promoting crop growth. The efficient organic fertilizer preparation method based on sheep manure in the present invention not only realizes the recycling of resources, but also significantly improves the performance of organic fertilizers through scientific technological steps and raw material ratios. The following is a detailed analysis of the technical principle, the role of raw materials, the synergistic effect, and the optimization of process parameters.

[0023] I. Technical Principle

[0024] The technology of the present invention takes sheep manure as the main raw material, and through a series of chemical reactions and physical treatments, converts the organic matter and nutrients in sheep manure into highly efficient and easily absorbable organic fertilizers. The specific steps include the crushing and mixing of sheep manure, hydrothermal reaction, centrifugal filtration, acid-base adjustment, precipitation filtration, drying, and final mixing, etc. Each step is carefully designed to maximize the extraction and retention of nutrients in sheep manure, while removing harmful substances and improving the quality of organic fertilizers.

[0025] II. Role of Raw Materials and Synergistic Effect

[0026] 1. Sheep manure: As the main raw material, sheep manure is rich in essential elements for crops such as organic matter, nitrogen, phosphorus, and potassium. Through the crushing treatment, the specific surface area of sheep manure is increased, which is beneficial to the subsequent reactions.

[0027] 2. Potassium hydroxide: As an alkaline catalyst, potassium hydroxide plays a role in adjusting the pH value and promoting the decomposition of organic matter in the reaction. At the same time, it also undergoes chemical reactions with certain components in sheep manure to generate nutrients that are more easily absorbed by plants.

[0028] 3. Iron(III) hydroxide: As an efficient adsorbent, iron(III) hydroxide can adsorb heavy metals and other harmful substances in sheep manure, purifying the organic fertilizer. In addition, it can act synergistically with potassium hydroxide to enhance the reaction effect.

[0029] 4. Deionized water: In the hydrothermal reaction, deionized water serves as a solvent and heat transfer medium, promoting the mixing and reaction between reactants. At the same time, it also helps to dissolve the reaction products in water, facilitating subsequent centrifugation and filtration operations.

[0030] These raw materials have a significant synergistic effect. The addition of potassium hydroxide and iron(III) hydroxide not only improves the extraction efficiency of nutrients in sheep manure, but also purifies the organic fertilizer, making it safer and more efficient. The high-temperature and high-pressure conditions of the hydrothermal reaction further promote the decomposition and transformation of organic matter in sheep manure, generating more nutrients that are easily absorbed by plants.

[0031] III. Necessity and Importance of Optimizing Process Parameters

[0032] 1. Raw material dosage: The optimization of raw material dosage is the key to ensuring the quality of organic fertilizer. Through single-factor experiments, it is found that when the mass ratio of sheep manure to potassium hydroxide is 10:1.5, the quality of the obtained humic acid is the best. This indicates that at this ratio, the catalytic effect of potassium hydroxide is the best, and it can maximize the extraction of nutrients from sheep manure.

[0033] 2. Process parameters: Process parameters such as the temperature, time of the hydrothermal reaction, and stirring time also have an important impact on the quality of organic fertilizer. By optimizing these parameters, it is possible to ensure that the reaction proceeds fully while avoiding nutrient loss caused by overreaction. For example, when the hydrothermal temperature is controlled at 250 °C and the heat preservation time is 2 hours, it can ensure the full decomposition of organic matter; and when the stirring time is controlled at 20 - 30 minutes, it is beneficial to the full mixing of reactants.

[0034] 3. Centrifugation and filtration: Centrifugation and filtration operations are key steps to remove impurities and improve the purity of organic fertilizer. Using a centrifuge and a vacuum filtration machine for centrifugation and filtration can ensure that impurities are completely removed while retaining as many nutrients as possible.

[0035] 4. Acid-base adjustment and precipitation: By adjusting the pH value of the filtrate, the target product can be allowed to stand and precipitate. This step not only helps to remove excess acid and base substances but also enables effective components such as humic acid to precipitate better. A refrigerated environment helps to accelerate the precipitation process and improve the precipitation efficiency.

[0036] 5. Drying and mixing: The drying operation can remove the moisture in the organic fertilizer and improve its stability; while the mixing operation can ensure the uniform distribution of humic acid and hydrothermal carbon organic matter, improving the fertilizer efficiency of the organic fertilizer.

[0037] Through the optimization of these process parameters, not only the quality and fertilizer efficiency of the organic fertilizer are improved, but also the production cost is reduced, achieving the maximum utilization of resources.

[0038] IV. Unexpected technical effects

[0039] The high-efficiency organic fertilizer preparation technology based on sheep manure has achieved unexpected technical effects. First of all, the humic acid content of this organic fertilizer is greater than 20%, and the organic matter content is greater than 60%, far higher than that of traditional organic fertilizers. This means that this organic fertilizer has higher fertility and more lasting fertilizer efficiency. Secondly, this organic fertilizer is rich in essential elements for crops such as nitrogen, phosphorus, and potassium, which can meet various needs of crop growth. In addition, this organic fertilizer also has multiple effects such as improving soil structure, enhancing soil fertility, and promoting crop growth.

[0040] In summary, the efficient organic fertilizer preparation technology based on sheep manure not only realizes the recycling of resources and the harmless treatment of waste, but also significantly improves the performance and quality of organic fertilizers through scientific technological steps and raw material ratios. The successful application of this technology will provide more high-quality and efficient organic fertilizer products for agricultural production and promote the sustainable development of agriculture.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] (1) The preparation method of the present invention is an efficient catalytic conversion technology with high extraction efficiency, low energy consumption, and easily available catalysts.

[0043] (2) The catalyst of the present invention is iron hydroxide, which is green and harmless in agricultural operations, and the supplementation of iron elements is beneficial to chlorophyll synthesis, photosynthesis, and root development.

[0044] (3) The organic matter content of the present invention is greater than 60%, meeting the national standard (NY525 - 2021).

[0045] (4) Sheep manure is a solid biomass waste containing a large amount of useful elements such as C, H, O, and N. Using iron hydroxide as a catalyst, after pyrolyzing macromolecular lignocellulose, 100% utilization of solid waste raw materials is achieved, promoting the development of circular economy. At the same time, it also significantly reduces the time cost of manufacturing humic acid organic fertilizers, opening up a new path for the green transformation and sustainable development of the biomass solid waste industry. Description of the Drawings

[0046] Figure 1 is the preparation flow chart of humic acid organic fertilizer;

[0047] Figure 2 is the stratification phenomenon diagram of the acidified filtrate during refrigeration precipitation;

[0048] Figure 3 is the diagram of the pure humic acid sample after washing and drying;

[0049] Figure 4 is the ultraviolet and infrared spectrogram of humic acid;

[0050] Figure 5 is the germination rate diagram of pea seeds applied with different fertilizers. Detailed Embodiments

[0051] The following further elaborates on the present invention in combination with specific embodiments. These embodiments should be understood as only for illustrating the present invention and not for limiting the protection scope of the present invention. After reading the content recorded in the present invention, various changes or modifications made to the present invention based on the principle of the present invention also fall within the scope defined by the claims of the present invention. In this embodiment, the preparation flow schematic diagram of the present invention is as shown in Figure 1 shown.

[0052] Example 1

[0053] Mix 100 g of sheep manure with 15 g of potassium hydroxide and 0.01 g of iron oxyhydroxide, then add 200 ml of deionized water and stir for 20 min. Put the slurry into a hydrothermal reactor with a PPL inner liner and conduct hydrothermal reaction in a forced-air oven. Set the temperature at 250 °C and the holding time at 2 h. After the reaction, centrifuge the slurry and filter the upper liquid using a vacuum filter to obtain the filtrate and the solid residue after filtration. Then slowly drop 30% hydrochloric acid into the filtrate to lower the pH of the filtrate to below 2, and place it in the refrigerator for overnight precipitation; wash the filter residue 5 times with deionized water using a vacuum filter to obtain the hydrochar matrix. Filter out the overnight precipitate and wash it 5 times with deionized water to obtain humic acid. Then dry the two solids in a forced-air oven at 60 °C for 10 hours, and finally obtain a mixture of 20 g of humic acid and 70 g of hydrochar. Grind and mix the two evenly to prepare an organic fertilizer rich in humic acid.

[0054] Figure 2 During the preparation of humic acid in Example 1, it is the precipitation phenomenon after acidification and refrigeration of the filtrate filtered from the hydrothermal slurry. Due to the property of humic acid being insoluble in acid but soluble in base, when the pH of the solution is lowered to below 2 using hydrochloric acid, there is an obvious precipitation effect of humic acid.

[0055] Figure 3 The humic acid sample after washing and drying in Example 1 has been washed 5 times to remove the salt ions therein, such as Cl - etc.

[0056] Example 2

[0057] Mix 100 g of sheep manure with 20 g of potassium hydroxide and 0.01 g of iron oxyhydroxide, then add 200 ml of deionized water and stir for 20 min. Put the slurry into a hydrothermal reactor with a PPL inner liner and conduct hydrothermal reaction in a forced-air oven. Set the temperature at 250 °C and the holding time at 2 h. After the reaction, centrifuge the slurry and filter the upper liquid using a vacuum filter to obtain the filtrate and the solid residue after filtration. Then slowly drop 30% hydrochloric acid into the filtrate to lower the pH of the filtrate to below 2, and place it in the refrigerator for overnight precipitation; wash the filter residue 5 times with deionized water using a vacuum filter to obtain the hydrochar matrix. Filter out the overnight precipitate and wash it 5 times with deionized water to obtain humic acid. Then dry the two solids in a forced-air oven at 60 °C for 10 hours, and finally obtain a mixture of 22 g of humic acid and 68 g of hydrochar. Grind and mix the two evenly to prepare an organic fertilizer rich in humic acid.

[0058] Table 1 shows the elemental contents in the humic acid sample prepared in Example 2.

[0059] Table 1 shows the elemental contents of humic acid

[0060] sample N(％) C(％) H(％) S(％) O(％) humic acid 2.38 49.45 4.97 0.71 20.91

[0061] Since humic acid is rich in functional groups such as carboxyl, ketone, alkane, and phenolic hydroxyl groups, elements such as C and O are abundant, which are important indicators of humic acid products.

[0062] Figure 4 They are the ultraviolet spectrum and infrared spectrum of the humic acid sample in Example 2. From the absorbance ratio at wavelengths of 465 nm and 665 nm in the ultraviolet spectrum, the degree of humification of humic acid can be obtained as 9.58, which is an important indicator of humic acid products. The peaks at wavelengths of 3401 nm, 2926 nm, 1720 nm, and 1208 nm in the infrared spectrum represent -OH, -CH2, C=O, and C=C respectively. These functional groups play important roles in promoting plant growth, improving soil structure, and enhancing plant stress resistance.

[0063] Figure 5 They are the effects of the humic acid organic fertilizer prepared in Example 2 and two other groups on the germination rate of peas. By applying Hoagland nutrient solution, tap water, and the product of the present invention and comparing the germination rates of pea seeds, it is obvious that the humic acid organic fertilizer product prepared by the present invention has a positive effect on promoting pea germination.

Claims

1. A method for preparing high-efficiency organic fertilizer based on sheep manure, characterized in that: The following steps are involved: (1) crushing sheep manure, adding a certain proportion of potassium hydroxide and ferric oxyhydroxide and mixing; (2) adding water to the mixed material and stirring it evenly, performing a hydrothermal reaction under high temperature and high pressure conditions for a certain period of time, and obtaining a slurry through catalytic conversion; (3) cooling the slurry, centrifuging and filtering to obtain a filtrate and a filter residue; (4) adding a certain amount of acid solution to the filtrate to adjust the pH value, allowing the target product to precipitate, and then filtering, washing, and drying the precipitate to obtain humic acid; (5) washing the filter residue with water and drying it to obtain a hydrothermal carbon matrix; (6) Grinding and mixing the humic acid in step (4) and the hydrothermal carbon matrix in step (5) to obtain humic acid high-efficiency organic fertilizer.

2. The method for preparing high-efficiency organic fertilizer based on sheep manure according to claim 1, characterized in that: The mass ratio of sheep manure to potassium hydroxide in step (1) is 10:1-2, the mass ratio of sheep manure to ferric oxyhydroxide is 10000:1-5, and the particle size is 500-700 meshes.

3. The method for preparing high-efficiency organic fertilizer based on sheep manure according to claim 1, characterized in that: The mass ratio of sheep manure to potassium hydroxide in step (1) is 10:1-2.

4. The method for preparing high-efficiency organic fertilizer based on sheep manure according to claim 3, characterized in that: The mass ratio of the sheep manure to potassium hydroxide is 10:1.

5.

5. The method for preparing high-efficiency organic fertilizer based on sheep manure according to claim 1, characterized in that: The liquid-to-solid ratio of the mixed material in step (2) is 1-2:1, the stirring time is 20-30 minutes, the hydrothermal temperature is 220-250° C., and the insulation time is 1-2 hours.

6. The method for preparing high-efficiency organic fertilizer based on sheep manure according to claim 1, characterized in that: In step (4), the pH of the filtrate is adjusted to below 2 with acid solution, and the precipitation process needs to be placed in a refrigerated environment for 10 to 12 hours.

7. The method for preparing high-efficiency organic fertilizer based on sheep manure according to claim 6, characterized in that: The filtered solid is dried at 60-80°C for 10-12 hours to obtain humic acid.

8. The method for preparing high-efficiency organic fertilizer based on sheep manure according to claim 1, characterized in that: The mixing ratio of humic acid to hydrocharcoal matrix in step (6) is 1:3-4, and the mixture is fully mixed by grinding for 20-30 minutes to finally obtain humic acid organic fertilizer solid powder.

9. The method for preparing high-efficiency organic fertilizer based on sheep manure according to claim 8, characterized in that: The obtained organic fertilizer is sealed and moisture-proof and stored.

10. A high-efficiency organic fertilizer based on sheep manure prepared according to the method according to any one of claims 1 to 9, characterized in that: The organic matter content is greater than 60%, the humic acid content is greater than 20%, and it is rich in nitrogen, phosphorus and potassium.

Images