Preparation process of graphene organic fertilizer

Abstract

The application discloses a kind of production processes of graphene organic fertilizer, belong to organic fertilizer preparation technical field.The application directly uses commercial raw materials, without high-temperature modification, by pig manure pretreatment, mixing dispersion, medium-high temperature subsection fermentation and post-processing to obtain composite organic fertilizer.The process is optimized by subsection temperature control and aeration, and the fermentation cycle is 18-22 days, with high degree of decomposition, which is more than 30% higher than the efficiency of traditional process.The production cost of the application is reduced by 80% compared with the traditional process, the production process is odorless and easy to scale production, the organic matter content of the product is ≥58%, the mortality rate of insect eggs is 99%, and the product has heavy metal passivation and soil improvement functions, which can significantly improve crop yield, suitable for livestock and poultry manure resource utilization, in line with relevant national policies, with outstanding economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of organic bio-fertilizer preparation technology, specifically to a process for producing graphene organic fertilizer. Background Technology

[0002] With the acceleration of agricultural modernization, traditional livestock and poultry manure composting suffers from problems such as low fertilizer efficiency, long fermentation cycles, and incomplete elimination of pests and diseases. Graphene-based fertilizers, however, have become a research hotspot in the fertilizer field due to their advantages such as slow nutrient release, soil remediation, and enhanced microbial activity. Currently, some technical solutions for combining graphene materials with livestock and poultry manure to prepare organic bio-fertilizers have been disclosed, but existing technologies still have many shortcomings that urgently need to be addressed.

[0003] In the existing technology, CN109879709A discloses a biochar-based organic fertilizer and its preparation method. This technology uses pig manure as the main raw material and adds graphene / Mn / biochar composite modification material to achieve yield increase through two-stage fermentation. However, this technology has obvious shortcomings: First, graphene needs to be mixed with corn stalk residue powder and manganese chloride, and then undergo multiple processes such as heating at 90-110℃, high-temperature carbonization at 500-600℃, and ash removal for composite modification. The process is complex and energy-intensive, which greatly increases the cost of industrial production. Second, the formula requires the addition of more than 6 specific auxiliary materials such as brewer's lees and zinc potassium humate. The raw material compatibility is poor, which is not conducive to large-scale promotion. Third, the fermentation process only controls the basic temperature range and does not design a precise temperature, humidity, and aeration control strategy for the synergistic effect of graphene and pig manure, resulting in limited organic matter degradation efficiency and a fermentation cycle of 25-32 days.

[0004] CN201710645000.0 discloses a graphene oxide compound fertilizer and its preparation method. This technology uses graphene oxide and polymers to prepare a coating material, achieving controlled release of fertilizer nutrients. However, the core defects of this technology are: firstly, graphene requires complex treatments such as oxidation modification and polymer coating, preventing the direct application of commercially available finished products; secondly, the raw material system is mainly based on chemical fertilizers, lacking organic raw materials such as pig manure, failing to meet the dual needs of organic matter supply and soil improvement; and thirdly, the process route involves chemical coating and molding without a biological fermentation step, resulting in a lack of microbial activity and poor fertilizer efficacy.

[0005] In addition, CN108117459A discloses a fermented organic fertilizer made from pig manure and its preparation method. This technology adds carbon nanotubes to improve fertilizer efficiency, but the carbon material is carbon nanotubes rather than graphene, and only adopts an aerobic fermentation mode with natural heating. There is no precise control of process parameters, resulting in problems such as insufficient fermentation, low kill rate of pests and diseases, and unstable fertilizer efficiency.

[0006] Existing technologies also have significant shortcomings in adjusting the carbon-nitrogen ratio: they generally use a single straw material, which is difficult to adapt to the graphene organic fertilizer system, and is prone to problems such as carbon-nitrogen ratio imbalance, insufficient air permeability, and uneven fermentation, resulting in low composting efficiency and large fluctuations in product quality.

[0007] In summary, existing technologies in the field of graphene and pig manure co-fermentation generally adopt the technical route of "graphene composite modification + multi-auxiliary material formulation + extensive fermentation control". This approach has drawbacks such as complex processes, high costs, single functions, and poor adaptability of carbon-nitrogen ratio adjustment, and cannot meet the actual needs of agricultural production for low-cost, high-efficiency, and multifunctional organic bio-fertilizers. Summary of the Invention

[0008] (a) Purpose of the invention The purpose of this invention is to provide a process for producing graphene organic fertilizer, which solves the problems of graphene requiring composite modification, complex process, high cost, single fertilizer effect, and poor adaptability of carbon-nitrogen ratio adjustment in the existing technology, so as to achieve low-cost and high-efficiency preparation of organic bio-fertilizer, while also having multiple functions such as slow release of nutrients, adsorption of heavy metals in soil, and improvement of crop quality.

[0009] A process for manufacturing graphene organic fertilizer includes the following steps:

[0010] Collect fresh pig manure, remove impurities such as gravel and plastic, and use mechanical crushing to control the particle size of pig manure to ≤5mm; adjust the initial moisture content of pig manure to 55%-65%; adjust the C / N ratio to 25-30 by adding a carbon-nitrogen ratio regulator; after pretreatment, let it stand for 24 hours to reduce the inhibitory effect of volatile fatty acids on the microbial community.

[0011] Commercially available powdered graphene organic fertilizer with an effective graphene content ≥0.05% was selected; the graphene organic fertilizer was mixed with pretreated pig manure at a mass ratio of 1:8-1:12; and dispersed using a method of "low-speed mechanical stirring + intermittent turning and scattering". Stir at 80-100 rpm for 30 minutes each time, with a 2-hour interval, for a total of 3 times. After stirring, turn the mixture over once a day to ensure uniform dispersion of graphene.

[0012] The materials are piled into fermentation heaps 1.2-1.5m high, and medium- and high-temperature staged control is adopted: First 7 days: Temperature 32-38℃, ventilation 0.3 m³ / (m³·h), to activate the gut microbiota. Days 8-15: Raise the temperature to 50-55℃, increase ventilation to 0.5 m³ / (m³·h), and sterilize and kill eggs. The humidity is controlled at 60%-70% throughout the process, requiring no additional water replenishment, and the total fermentation cycle is 18-22 days.

[0013] After fermentation, the product is dried until the moisture content is ≤15%, then granulated into 2-4mm granules using a disc granulator. Utilizing the properties of graphene, no binder is required, and the molding rate is ≥92%. The product is sealed in packaging and has a shelf life of ≥12 months.

[0014] Furthermore, the carbon-nitrogen ratio regulator is one or more of corn stalk powder, wheat stalk powder, rice husk, and sawdust, with a particle size ≤3mm, and the addition amount is 3%-8% of the weight of pig manure (sawdust used alone shall not exceed 5%).

[0015] Furthermore, the graphene organic fertilizer is preferably a microbial compound formulation containing at least one of Bacillus subtilis, yeast, and actinomycetes.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] It directly uses commercially available graphene organic fertilizer, eliminating the need for complex pretreatments such as oxidation, modification, coating, and high-temperature compounding of graphene. The formula consists only of graphene organic fertilizer, pig manure, and a multi-component carbon-nitrogen ratio regulator. The raw materials are simple and readily available, and the process steps are reduced by more than 60% compared to traditional technologies, resulting in a reduction of more than 80% in overall production costs. It is suitable for large-scale, low-cost promotion and application.

[0018] Through this process, the organic matter degradation rate of the material is ≥85%, the fermentation cycle is shortened from the traditional 30-45 days to 18-22 days, and the fermentation efficiency is increased by more than 30%. According to NY 525-2021 "Organic Fertilizer" and GB 7959-2012 "Sanitary Requirements for Harmless Treatment of Feces", the ascarid egg mortality rate of the fermentation product is ≥99%, the fecal coliform count meets the harmless sanitation standard, pathogens and parasite eggs are thoroughly killed, and the composting is uniform and stable. The product fully complies with national organic fertilizer and sanitary safety requirements.

[0019] According to tests conducted by a third-party agricultural testing institution and field plot trials (3 replicates, randomized block design), the fertilizer of this invention shows outstanding performance in soil remediation, crop growth promotion, quality improvement, and yield increase. Soil cadmium (Cd) and lead (Pb) passivation adsorption rate ≥75% (testing standard: NY / T 3499-2019); A pot experiment on crop seedlings at 45 days showed that root biomass increased by ≥30% and root vigor was significantly enhanced. Field demonstration trials (rice, leafy greens, and chili peppers) showed an average yield increase of 18.0%-27.3%. The nitrate content of agricultural products decreased by 15.0%-20.0% (testing basis: GB 5009.167-2014).

[0020] The product has multiple functions including slow release of nutrients, passivation of heavy metals, activation of microorganisms, and soil improvement. It is suitable for scenarios such as greenhouse vegetables, continuous cropping obstacle management in orchards, and improvement of acidified soil.

[0021] Carbon-nitrogen ratio regulators can be made from common agricultural wastes such as corn stalk powder, wheat stalk powder, rice husks, and sawdust, and can be flexibly formulated according to the availability of raw materials in the region. The process conditions are mild and do not require special or complicated equipment. It can be used for large-scale factory production as well as for small and medium-sized farms for local resource treatment, with significant environmental and economic benefits. Attached Figure Description Figure 1 This is a schematic diagram of the manufacturing process of a graphene organic fertilizer according to the present invention. The illustrated steps include: pretreatment of pig manure, mixing and dispersing of raw materials, medium-high temperature staged fermentation, post-processing of the product, and sealing and packaging. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0023] The raw materials and testing methods used in this embodiment all comply with relevant national and agricultural industry standards. The test site is an agricultural test base in a subtropical monsoon climate zone, with an ambient temperature of 20-32℃ and a relative humidity of 60%-80%. Example

[0024] A manufacturing process for a graphene organic fertilizer, see [link / reference]. Figure 1 The specific steps are as follows:

[0025] Collect fresh pig manure, remove impurities such as gravel and plastic, and mechanically crush it to a particle size ≤5mm; adjust the moisture content to 60%; add corn stalk powder as a carbon-nitrogen ratio regulator, the amount added is 5% of the mass of pig manure, and adjust the C / N ratio to 27; after pretreatment, let it stand for 24 hours.

[0026] Commercially available graphene organic fertilizer (containing Bacillus subtilis and yeast) with an effective graphene content of 0.06% was selected and mixed with pretreated pig manure at a mass ratio of 1:10. Low-speed stirring + intermittent turning and dispersing were adopted: stirring speed 90r / min, stirring for 30min each time, with an interval of 2h, for a total of 3 stirrings; after stirring, the mixture was turned and dispersed once a day to ensure uniform mixing.

[0027] The materials were piled into a 1.3m high fermentation pile, and fermented in stages with controlled temperature. For the first 7 days, control the temperature at 32-38℃ and the ventilation rate at 0.3 m³ / (m³·h); From day 8 to 15, maintain a temperature of 50-55℃ and a ventilation rate of 0.5 m³ / (m³·h). The humidity is maintained at 60%-70% throughout the process, and the total fermentation cycle is 20 days.

[0028] After fermentation, the product is naturally dried until the moisture content is 13%, then granulated into approximately 3mm particles using a disc granulator with a molding rate of 94%, and sealed in packaging for later use.

[0029] Performance test results (based on corresponding national / industry standards): Organic matter degradation rate: 87%; The mortality rate of Ascaris eggs was 99.5%, meeting the harmlessness requirements of GB 7959-2012; Soil Cd and Pb passivation adsorption rate was 77% (NY / T 3499-2019). Field trials of Chinese cabbage showed a 21.4% increase in yield. The nitrate content in the leaves decreased by 17.2% (GB 5009.167-2014). Example

[0030] A manufacturing process for a graphene organic fertilizer, see [link / reference]. Figure 1 The specific steps are as follows:

[0031] Fresh pig manure was cleaned and pulverized to a particle size ≤5mm, and the moisture content was adjusted to 58%. A rice husk + sawdust compound regulator (mass ratio 3:1) was added at a total amount of 6%, and the C / N ratio was adjusted to 28. The mixture was then left to stand for 24 hours.

[0032] Select commercially available compound microbial agent type graphene organic fertilizer with an effective graphene content of 0.07%, mix it with pig manure at a mass ratio of 1:9; stir at a speed of 85 r / min, stir for 30 minutes each time, with an interval of 2 hours, stir 3 times, and turn it over once a day.

[0033] The pile height was 1.4m, the temperature was 33-37℃ for the first 7 days, and 51-54℃ for the 8th-15th days. The aeration rate was the same as in Example 1, and the fermentation cycle was 19 days.

[0034] Sun-dry until the moisture content is 14%, and the granulation rate is 93%.

[0035] Performance test results: Organic matter degradation rate: 86%; The mortality rate of Ascaris eggs was 99.3%; Soil Cd and Pb passivation adsorption rates were 76%; Rice plot trials showed a yield increase of 24.7%; Rice nitrate levels decreased by 18.5%. Example

[0036] A manufacturing process for a graphene organic fertilizer, see [link / reference]. Figure 1 The specific steps are as follows:

[0037] Fresh pig manure was cleaned and pulverized to a particle size ≤5mm, and the moisture content was adjusted to 62%. Wheat straw powder was added as a carbon-nitrogen ratio regulator at a rate of 7% of the pig manure mass to adjust the C / N ratio to 26. The mixture was then left to stand for 24 hours.

[0038] Commercially available graphene organic fertilizer with an effective graphene content of 0.05% was selected and mixed with pretreated pig manure at a mass ratio of 1:11. The stirring speed was 100 r / min, and the stirring time was 30 min each time, with an interval of 2 h. The mixture was stirred 3 times and turned over once a day.

[0039] The pile height is 1.2m. The temperature is 34-38℃ for the first 7 days and 52-55℃ for the 8th-15th days. The aeration rate remains unchanged. The fermentation cycle is 21 days.

[0040] Sun-dry until the moisture content is 12%, and the granulation rate is 95%.

[0041] Performance test results: Organic matter degradation rate: 88%; The mortality rate of Ascaris eggs was 99.6%; Soil Cd and Pb passivation adsorption rates were 78%; Chili peppers yielded an increase of 26.8% in field trials; The nitrate content of the fruit decreased by 19.1%. Example

[0042] A manufacturing process for a graphene organic fertilizer, see [link / reference]. Figure 1 The specific steps are as follows:

[0043] Fresh pig manure was cleaned and pulverized to a particle size ≤5mm, and the moisture content was adjusted to 65%. A compound regulator of corn stalk powder and rice husk (mass ratio 1:1) was added, with a total addition of 8%, and the C / N ratio was adjusted to 29. The mixture was then left to stand for 24 hours.

[0044] Commercially available graphene organic fertilizer with an effective graphene content of 0.06% was selected and mixed with pretreated pig manure at a mass ratio of 1:12. The stirring speed was 80 r / min, and the stirring was carried out for 30 minutes each time, with an interval of 2 hours. The mixture was stirred 3 times and turned over once a day.

[0045] The pile was 1.5m high, the temperature was 32-36℃ for the first 7 days, and 50-53℃ for the 8th-15th days. The aeration rate remained constant, and the fermentation cycle was 22 days.

[0046] Sun-dry until the moisture content is 15%, and the granulation rate is 92%.

[0047] Performance test results: Organic matter degradation rate: 85%; The mortality rate of Ascaris eggs was 99.2%; Soil Cd and Pb passivation adsorption rates were 75%; Rice field trials showed a yield increase of 18.2%; The nitrate content in rice decreased by 15.3%.

[0048] The same raw materials and proportions as in Example 1 were used, but the fermentation stage was not subject to segmented temperature control; it was simply natural composting fermentation over a period of 30 days.

[0049] Test results: The organic matter degradation rate is only 71%; Uneven fermentation and insufficient local temperature resulted in a 91.2% mortality rate for roundworm eggs, failing to meet the harmless and hygienic standards. The crop yield increase was only 8.3%, and the heavy metal adsorption rate was 59%.

[0050] This demonstrates that the segmented temperature control, multi-element carbon-nitrogen ratio adjustment, and precise process parameters of the present invention significantly improve fermentation effect, fertilizer efficiency, and safety.

Claims

1. A process for producing graphene organic fertilizer, characterized in that, Includes the following steps: (1) Pretreatment of pig manure: Collect fresh pig manure, remove impurities and crush it to a particle size ≤5mm; adjust the moisture content to 55%-65%; add carbon-nitrogen ratio adjuster to adjust the C / N ratio to 25-30; let it stand for 24 hours after pretreatment; (2) Raw material mixing and dispersion: Select commercially available graphene organic fertilizer with an effective graphene content ≥0.05% and mix it with pretreated pig manure at a mass ratio of 1:8-1:12; use low-speed mechanical stirring and intermittent turning and threshing for dispersion, stirring speed 80-100r / min, stirring for 30min each time, with an interval of 2h, for a total of 3 stirrings, and turning and threshing once a day after stirring is completed; (3) Medium- and high-temperature staged fermentation: The material is piled into a fermentation pile 1.2-1.5m high, and staged temperature-controlled fermentation is adopted. The temperature is 32-38℃ for the first 7 days and the aeration rate is 0.3m³ / (m³·h); the temperature is 50-55℃ for the 8th-15th days and the aeration rate is 0.5m³ / (m³·h); the humidity is controlled at 60%-70% throughout the process, and the fermentation cycle is 18-22 days; (4) Post-processing of the product: The fermented material is dried until the moisture content is ≤15%, then granulated into 2-4mm granules with a molding rate of ≥92%, and then sealed and packaged.

2. The process according to claim 1, characterized in that, The carbon-nitrogen ratio regulator is selected from one or more of corn stalk powder, wheat stalk powder, rice husk, and sawdust. The regulator particle size is ≤3mm, and the addition amount is 3%-8% of the weight of pig manure, of which sawdust alone does not exceed 5%.

3. The process according to claim 1, characterized in that, The graphene organic fertilizer is a microbial compound formulation containing at least one of Bacillus subtilis, yeast, and actinomycetes.

4. The process according to claim 1, characterized in that, No additional water is needed during the fermentation process.

5. The process according to claim 1, characterized in that, No binder is required for product granulation.

6. The process according to claim 1, characterized in that, After fermentation, the organic matter degradation rate of the material is ≥85%.

7. The process according to claim 1, characterized in that, The mortality rate of Ascaris eggs in the fermentation products is ≥99%, and the fecal coliform count meets the requirements of GB 7959-2012 "Sanitary Requirements for Harmless Treatment of Feces".

8. The process according to claim 1, characterized in that, The graphene organic fertilizer used is a commercially available product and does not require oxidation, modification, coating, or high-temperature compounding treatment.

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