阅读说明：本技术 一种发酵牛粪制备硝基黄腐酸的方法及其设备 (Method and equipment for preparing nitrofulvic acid by fermenting cow dung ) 是由 程宽利 刘丽军 成绍鑫 高亚萍 吉子平 于 2019-12-26 设计创作，主要内容包括：本发明涉及一种发酵牛粪制备硝基黄腐酸的方法及其设备,采用专门培育的特种复合微生物作为发酵菌剂,发酵牛粪,以便定向生成以芳香族羟基羧酸为主的黄腐酸类产物,克服了用普通菌剂盲目发酵,黄腐酸产率低的缺憾；采用硝酸轻度催化氧化技术,不仅降低大分子生化腐植酸和黄腐酸的分子量,增加酸性官能团含量,而且在芳香族分子中引入硝基,进一步提高酸性官能团活性；硝酸氧化还可消除粪便中的虫卵、有害细菌和病毒,保证产品的安全；本发明所得硝基黄腐酸主要作为高效植物生长调节剂或水溶肥料,也可配入无机化肥制成高浓度多元素叶面肥料。农田试验表明,喷施硝基黄腐酸,不仅可使蔬菜、瓜果增产18～35％,而且具有改善作物品质、提高抗逆的功能。(The invention relates to a method for preparing nitrofulvic acid by fermenting cow dung and equipment thereof, wherein specially cultivated special compound microorganisms are used as a fermentation microbial inoculum to ferment the cow dung so as to directionally generate fulvic acid products mainly comprising aromatic hydroxycarboxylic acids, thereby overcoming the defects of blind fermentation by using a common microbial inoculum and low yield of the fulvic acid; by adopting a nitric acid mild catalytic oxidation technology, the molecular weight of macromolecular biochemical humic acid and fulvic acid is reduced, the content of acidic functional groups is increased, and the nitro is introduced into aromatic molecules, so that the activity of the acidic functional groups is further improved; the nitric acid oxidation can also eliminate worm eggs, harmful bacteria and viruses in the excrement, so that the safety of the product is ensured; the obtained nitrofulvic acid is mainly used as a high-efficiency plant growth regulator or a water-soluble fertilizer, and can be prepared into a high-concentration multi-element foliar fertilizer by being matched with an inorganic fertilizer. Farmland tests show that the spraying of the nitrofulvic acid can increase the yield of vegetables and melons and fruits by 18-35%, and has the functions of improving the quality of crops and improving the stress resistance.)

1. The method for preparing the nitrofulvic acid by fermenting the cow dung is characterized by comprising the following steps of:

(1) adding auxiliary materials into naturally air-dried cow dung to form a material to be fermented, and then inoculating brewing yeast for primary fermentation to form a primary fermentation material;

(2) inoculating the primary fermentation material in the step (1) with a complex microbial inoculum for secondary fermentation to form a secondary fermentation material;

(3) adding nitric acid into the secondary fermentation material obtained in the step (2) for oxidation; adding alkaline substance for neutralization and extraction to obtain extract;

(4) and (4) carrying out solid-liquid separation and washing on the extract obtained in the step (3) to respectively obtain nitrofulvic acid liquid and a nitrohumic acid byproduct.

2. The method for preparing nitrofulvic acid by fermenting cow dung according to claim 1, wherein in the step (1), the brewer's yeast is brewer's yeast Hm, and the number of effective viable bacteria of the brewer's yeast is not less than 8 x 10¹⁰Per gram.

3. The method for preparing nitrofulvic acid by fermenting cow dung according to claim 1, wherein in the step (1), the auxiliary materials comprise rice bran and humic acid, and the adding amount ratio of the cow dung to the rice bran to the humic acid is 6-10:2-5: 1-3.

4. The method for preparing nitrofulvic acid by fermenting cow dung according to claim 1, wherein 20 to 50kg of the brewer's yeast is added to per cubic meter of the material to be fermented in step (1).

5. The method for preparing nitrofulvic acid by fermenting cow dung according to claim 1, wherein in the step (2), the composite microbial inoculum comprises bacillus, pseudomonas, thermophilic sporotrichum and rhizopus, and the ratio of the number of viable bacteria of the bacillus, the pseudomonas, the thermophilic sporotrichum and the rhizopus is 4-6:3-5:3-5: 1-3; the effective viable count of the composite microbial inoculum is more than or equal to 9 multiplied by 10⁸Per gram; the addition amount of the complex microbial inoculum is 1-5% of the weight of the material to be fermented.

6. The method for preparing nitrofulvic acid by fermenting cow dung according to claim 5, wherein in the step (2), the complex microbial inoculum comprises Bacillus megaterium T3, Pseudomonas stutzeri B40, Bt Fie and Rhizopus 7 #.

7. The method for preparing nitrofulvic acid by fermenting cow dung according to claim 1, wherein in the step (1), before the brewing yeast is inoculated on the material to be fermented, the moisture content is adjusted to 50-65%, the carbon-nitrogen ratio is adjusted to 15-25:1, and the pH is adjusted to 5-7; in the step (2), before the compound microbial inoculum is inoculated on the primary fermentation material, the water content is adjusted to 65-80%, and the pH is adjusted to 5-7.

8. The method for preparing nitrofulvic acid by fermenting cow dung according to claim 1, wherein in the step (3), the mass ratio of the secondary fermentation material to the nitric acid is 100:3-5, and the catalyst added in the catalysis process is one of zinc sulfate, ferrous sulfate and sodium metavanadate.

9. The method for preparing nitrofulvic acid by fermenting cow dung according to any one of claims 1 to 8, wherein the method for preparing nitrofulvic acid by fermenting cow dung comprises the following steps:

(1) adding auxiliary materials into naturally air-dried cow dung to form a material to be fermented, adjusting the water content to be 50-65%, adjusting the carbon-nitrogen ratio to be 15-25:1 by using urea, adjusting the pH to be 5-7 by using ammonia water or KOH, then inoculating brewing yeast, uniformly mixing, stacking into a trapezoidal fermentation pile with the volume of more than 3 cubic meters for primary fermentation, and maintaining for 3 days after the temperature at the depth of 20-30cm of the fermentation pile is automatically raised to 40-50 ℃; then turning over the piles once, continuing to ferment and turning over the piles once every 3 days for 4-6 times to form a primary fermented material;

(2) putting the primary fermentation material obtained in the step (1) into a fermentation tank, adjusting the moisture of the primary fermentation material to 65-80%, adjusting the pH to 5-7, then inoculating a composite microbial inoculum, uniformly mixing, performing secondary fermentation, stirring once every 2h for 20min when the temperature of the primary fermentation material is raised to 30-40 ℃, and performing secondary fermentation for 7-10 days to form a secondary fermentation material;

(3) diluting nitric acid into nitric acid with the concentration of 50-60%, adding the nitric acid with the concentration of 50-60% slowly into the secondary fermentation material obtained in the step (2) for mild catalytic oxidation, wherein the mass ratio of the secondary fermentation material to the undiluted nitric acid is 100: 3-5; simultaneously adding a catalyst accounting for 0.1-0.3 percent of the weight of the secondary fermentation material, heating to 50-60 ℃, and reacting for 5-8 hours; adding KOH for neutralization to pH 7-8.5, heating to 50-65 deg.C, maintaining the temperature, and stirring for 1-2 hr to obtain extract;

(4) filtering the extract obtained in the step (3) in a filter for solid-liquid separation and washing to respectively obtain filtered liquid and solid filter residue, washing the solid filter residue with water, combining the filtered washing water with the filtered liquid, packaging and storing to obtain the nitrofulvic acid; the solid filter residue is nitro humic acid byproduct.

10. The apparatus for preparing nitrofulvic acid by fermenting cow dung according to claims 1 to 9, wherein the apparatus comprises a reaction kettle and a filter, and the reaction kettle is connected with the filter through a pipeline; the reaction kettle comprises an inner layer and an outer sleeve, an interlayer space is arranged between the inner layer and the outer sleeve, and a heating rod is arranged in the interlayer space; a stirring paddle is arranged in the reaction kettle, and a speed reduction motor is arranged at the top of the reaction kettle; the reaction kettle is fixed on the bracket, and a discharge valve and a slurry pump are arranged on the pipeline; the lower part of the filter is provided with a discharge hole.

Technical Field

The invention relates to a method for preparing nitrofulvic acid, in particular to a method for preparing nitrofulvic acid by fermenting cow dung and equipment thereof.

Background

With the rapid development of the intensification, scale and specialization of the modern breeding industry, the discharge amount of the livestock and poultry excrement is gradually increased. At present, the annual total discharge amount of livestock and poultry manure in China reaches about 60 hundred million tons, wherein the amount of cow manure is nearly half. Cow dung is an important organic fertilizer resource originally, but the treatment is still seriously delayed at present, the total consumption is less than 40%, so the problem of environmental pollution caused by dung is still outstanding, and the harmless and resource utilization of cow dung is still a problem to be solved urgently at present. Secondly, most of the existing cow dung treatment methods still use the technology of preparing organic fertilizer by using wild normal-temperature composting, and the used quick-rotting agent is mainly a conventional microbial agent. For example, CN107382472.A reports that a cow dung organic fertilizer fermentation microbial inoculum is common yeast, bacteria and actinomycetes. The Biochemical Fulvic Acid (BFA) technology which has emerged in recent years is a new technology of high-efficiency green environment-friendly bioactive preparation, but is prepared by fermenting biomass such as straws, vegetables, kitchen waste and the like, reports of BFA preparation by biochemical treatment of livestock and poultry manure are not found, and a zymogen of the BFA is not a special microorganism. For example, a BFA preparation method reported in cn110106225.a is prepared by inoculating a mixture of straw, wood chips, pomace and black paper-making liquid with a culture of aspergillus niger, yeast and bacillus, and fermenting. As reported in cn110117623.a, the BFA production process is prepared by adding vinasse powder, straws and livestock and poultry manure (only 0.1-0.2%) into fermentation yellow water of liquor-making waste liquid, inoculating common bacillus, and fermenting. Because of the non-specific culture of the BFA (mainly aromatic hydroxycarboxylic acid structure) preparing microorganism, the yield of the BFA product is low, and the BFA product hardly contains aromatic carboxylic acid and has low biological activity.

The invention takes the cow dung as the main fermentation substrate, can fully utilize the advantages of high humus content and high biological nutrients in the cow dung, solve the problem of environmental pollution caused by the dung, overcome the defect of extensive processing and utilization of the dung at present, and provide a new way for preparing efficient, cheap, green and environment-friendly agricultural products from the livestock and poultry dung.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a method and equipment for preparing nitrofulvic acid by fermenting cow dung, which is a method for preparing a high-activity biological agent, a liquid fertilizer and a byproduct humic acid organic fertilizer by using cow dung as a raw material through microbial fermentation and nitric acid oxidation.

The invention aims to provide a method for preparing nitrofulvic acid by fermenting cow dung.

According to the method for preparing the nitrofulvic acid by fermenting the cow dung, the method for preparing the nitrofulvic acid by fermenting the cow dung comprises the following steps:

(1) adding auxiliary materials into naturally air-dried cow dung to form a material to be fermented, and then inoculating brewing yeast for primary fermentation to form a primary fermentation material;

(2) inoculating the primary fermentation material in the step (1) with a complex microbial inoculum for secondary fermentation to form a secondary fermentation material;

(3) adding nitric acid and a catalyst into the secondary fermentation material obtained in the step (2) for catalytic oxidation; adding alkaline substance for neutralization and extraction to obtain extract;

(4) and (4) carrying out solid-liquid separation and washing on the extract obtained in the step (3) to respectively obtain nitrofulvic acid liquid and a nitrohumic acid byproduct.

According to the method for preparing nitrofulvic acid by fermenting cow dung, the brewing yeast is brewing yeast Hm in the step (1), and the effective viable count of the brewing yeast is more than or equal to 8 multiplied by 10¹⁰Per gram.

According to the method for preparing nitrofulvic acid by fermenting cow dung, disclosed by the embodiment of the invention, in the step (1), the auxiliary materials comprise bran coats and humic acid, and the adding amount ratio of the cow dung, the bran coats and the humic acid is 6-10:2-5: 1-3.

The method for preparing nitrofulvic acid by fermenting cow dung according to the embodiment of the invention, wherein in the step (1), 20-50kg of the brewer's yeast is added to per cubic meter of the material to be fermented.

According to the method for preparing nitrofulvic acid by fermenting cow dung, the compound microbial inoculum comprises bacillus, pseudomonas, thermophilic sporotrichum and rhizopus in the step (2).

According to the method for preparing the nitrofulvic acid by fermenting the cow dung, the ratio of the viable count of the bacillus, the pseudomonas, the sporotrichum thermophilum and the rhizopus is 4-6:3-5:3-5: 1-3.

The method for preparing nitrofulvic acid by fermenting cow dung according to the embodiment of the invention, wherein in the step (2), the complex microbial inoculum comprises bacillus megaterium T3, pseudomonas stutzeri B40, sporotrichum thermophilum Fie and rhizopus 7 #.

According to the method for preparing the nitrofulvic acid by fermenting the cow dung, the effective viable count of the compound microbial inoculum is more than or equal to 9 multiplied by 10 in the step (2)⁸Per gram.

According to the method for preparing the nitrofulvic acid by fermenting the cow dung, in the step (2), the adding amount of the composite microbial inoculum is 1-5% of the weight of the material to be fermented.

According to the method for preparing nitrofulvic acid by fermenting cow dung, disclosed by the specific embodiment of the invention, in the step (1), before the brewing yeast is inoculated on the material to be fermented, the moisture content is adjusted to be 50-65%, the carbon-nitrogen ratio is adjusted to be 15-25:1, and the pH is adjusted to be 5-7; in the step (2), before the compound microbial inoculum is inoculated on the primary fermentation material, the water content is adjusted to 65-80%, and the pH is adjusted to 5-7.

According to the method for preparing the nitrofulvic acid by fermenting the cow dung, in the step (3), the mass ratio of the secondary fermentation material to the nitric acid is 100:3-5, and the catalyst added in the catalysis process is one of zinc sulfate, ferrous sulfate and sodium metavanadate.

According to the method for preparing the nitrofulvic acid by fermenting the cow dung, the method for preparing the nitrofulvic acid by fermenting the cow dung further comprises the following steps:

(1) adding auxiliary materials into naturally air-dried cow dung to form a material to be fermented, adjusting the water content to be 50-65%, adjusting the carbon-nitrogen ratio to be 15-25:1 by using urea, adjusting the pH to be 5-7 by using ammonia water or KOH, then inoculating brewing yeast, uniformly mixing, stacking into a trapezoidal fermentation pile with the volume of more than 3 cubic meters for primary fermentation, and maintaining for 3 days after the temperature at the depth of 20-30cm of the fermentation pile is automatically raised to 40-50 ℃; then turning over the piles once, continuing to ferment and turning over the piles once every 3 days for 4-6 times to form a primary fermented material;

(2) putting the primary fermentation material obtained in the step (1) into a fermentation tank, adjusting the moisture of the primary fermentation material to 65-80%, adjusting the pH to 5-7, then inoculating a composite microbial inoculum, uniformly mixing, performing secondary fermentation, stirring once every 2h for 20min when the temperature of the primary fermentation material is raised to 30-40 ℃, and performing secondary fermentation for 7-10 days to form a secondary fermentation material;

(3) diluting nitric acid into nitric acid with the concentration of 50-60%, adding the nitric acid with the concentration of 50-60% slowly into the secondary fermentation material obtained in the step (2) for mild catalytic oxidation, wherein the mass ratio of the secondary fermentation material to the undiluted nitric acid is 100: 3-5; simultaneously adding a catalyst accounting for 0.1-0.3 percent of the weight of the secondary fermentation material, heating to 50-60 ℃, and reacting for 5-8 hours; adding KOH for neutralization to pH 7-8.5, heating to 50-65 deg.C, maintaining the temperature, and stirring for 1-2 hr to obtain extract;

(4) filtering the extract obtained in the step (3) in a filter for solid-liquid separation and washing to respectively obtain filtered liquid and solid filter residue, washing the solid filter residue with water, combining the filtered washing water with the filtered liquid, packaging and storing to obtain the nitrofulvic acid; the solid filter residue is nitro humic acid byproduct.

The method for preparing nitrofulvic acid by fermenting cow dung according to an embodiment of the present invention, wherein the brewery yeast used in step (1) is a strain selected and cultured from yeast used for brewing beer.

According to the method for preparing the nitrofulvic acid by fermenting the cow dung, disclosed by the specific embodiment of the invention, in the step (1), the auxiliary materials are the bran coat and the humic acid, and the addition amount of the humic acid is 10% of the weight of the cow dung.

According to the method for preparing nitrofulvic acid by fermenting cow dung, disclosed by the specific embodiment of the invention, in the step (1), the bran coat is one of rice hull, wheat bran and sorghum hull.

According to the method for preparing nitrofulvic acid by fermenting cow dung, disclosed by the invention, in the step (1), the humic acid is crushed and then sieved by a 80-mesh sieve, and the humic acid is weathered coal powder, lignite powder or coal humic acid powder with the content of more than or equal to 60%.

The complex microbial inoculum is cultured by adopting a special technology. In the step (2), the preparation method of the complex microbial inoculum comprises the following steps: inoculating bacillus megatherium T3, pseudomonas stutzeri B40, sporotrichum thermophilum Fie and rhizopus 7# in a test tube at 25-30 ℃, mixing the 4 inocula in proportion after 24 hours, culturing in a shake flask for 18-24 hours, then inoculating the mixed inocula into a fermentation tank according to 8-15% of the weight of the primary fermentation material, introducing air, stirring and fermenting for 18-24 hours until the number of viable bacteria reaches 9 multiplied by 10⁸And finishing the preparation of the complex microbial inoculum after each gram.

The quality indexes of the obtained nitrofulvic acid are as follows: the pH is 7-8.5, the content of nitrofulvic acid is more than or equal to 30 percent, the content of amino acid is more than or equal to 5 percent, the total content of nucleic acid, low-molecular organic acid, saccharides and inositol is more than or equal to 8 percent, and the content of insoluble substances is less than or equal to 1 percent; the total heavy metal content is less than or equal to 20mg/L, the detection rate of fecal escherichia coli is zero, and the death rate of ascarid eggs is more than or equal to 99 percent.

The nitro humic acid prepared by the invention can be used as a plant high-end growth regulator, a liquid fertilizer or a raw material for producing a multi-element spray fertilizer; the paste by-product can be sent to a fertilizer factory to be used as a raw material for producing organic fertilizer or organic-inorganic compound fertilizer.

The equipment for preparing the nitrofulvic acid by fermenting the cow dung comprises a reaction kettle and a filter, wherein the reaction kettle is connected with the filter through a pipeline; the reaction kettle comprises an inner layer and an outer sleeve, an interlayer space is arranged between the inner layer and the outer sleeve, and a heating rod is arranged in the interlayer space; the reactor is characterized in that a stirring paddle is arranged in the reactor, a feed inlet is arranged at the side top of the reactor, and a discharge outlet is arranged at the lower part of the filter.

The equipment for preparing the nitrofulvic acid by fermenting the cow dung is characterized in that the reaction kettle is fixed on a reaction kettle bracket.

According to the equipment for preparing the nitrofulvic acid by fermenting the cow dung, the discharge valve is arranged on the pipeline.

The equipment for preparing the nitrofulvic acid by fermenting the cow dung is provided with a mud pump on the pipeline.

According to the equipment for preparing the nitrofulvic acid by fermenting the cow dung, the reduction motor for controlling the stirring paddle is arranged at the upper outer side part of the reaction kettle.

The device for preparing nitrofulvic acid by fermenting cow dung according to the embodiment of the invention, wherein the inner layer is made of stainless steel material.

According to the equipment for preparing the nitrofulvic acid by fermenting the cow dung, the lower part of the speed reducer is provided with the speed reducer bracket.

According to the equipment for preparing the nitrofulvic acid by fermenting the cow dung, the other upper side surface opposite to the feeding port is provided with the water replenishing pipe.

According to the equipment for preparing the nitrofulvic acid by fermenting the cow dung, one end of the water supplementing pipe extends into the reaction kettle, and a spraying device is arranged at one end extending into the reaction kettle.

The equipment for preparing the nitrofulvic acid by fermenting the cow dung according to the specific embodiment of the invention is characterized in that the spraying device is a shower nozzle or an atomizing nozzle.

The device for preparing the nitrofulvic acid by fermenting the cow dung according to the embodiment of the invention, wherein a filtering membrane with 100-200 meshes is arranged in the filtering machine.

The invention has the beneficial effects that: the method for preparing the nitrofulvic acid by fermenting the cow dung takes the cow dung as a main material of an organic matrix, and obtains a nitrofulvic acid solution and a byproduct nitrohumic acid paste body after the fermentation of a special compound microbial agent, the mild oxidative degradation of dilute nitric acid, the neutralization, the extraction, the separation and the washing;

(1) the invention adopts special compound microorganism as fermentation microbial inoculum to directionally generate fulvic acid products mainly comprising aromatic hydroxycarboxylic acid, thus overcoming the defect that the yield of fulvic acid is low due to blind fermentation by using common microbial inoculum;

(2) by adopting the nitric acid mild catalytic oxidation technology, the molecular weight of macromolecular biochemical humic acid and fulvic acid is reduced, the content of acidic functional groups is increased, and nitro (-NO) is introduced into aromatic molecules₂) Further improving the activity of the acidic functional group; the nitric acid oxidation can also eliminate worm eggs, harmful bacteria and viruses in the excrement, so that the safety of the product is ensured;

(3) the preparation method of the invention can also provide liquid nitrofulvic acid products and byproduct pasty nitrohumic acid residues without any discharge. The former is a high-end plant growth promoter and a liquid fertilizer, and is also a raw material for preparing a high-quality multi-element composite water-soluble fertilizer; the latter is a high-end humic acid organic fertilizer and is also a high-quality raw material for preparing a high-performance organic-inorganic compound fertilizer;

(4) the obtained nitrofulvic acid is mainly used as a high-efficiency plant growth regulator or a water-soluble fertilizer, and can be prepared into a high-concentration multi-element foliar fertilizer by being matched with an inorganic fertilizer. As shown in farmland tests, the application of the nitro fulvic acid obtained by the method can increase the yield of vegetables and melons by 18-35%, and the nitro fulvic acid has the functions of improving the crop quality and improving the stress resistance (drought resistance, cold resistance, disease and insect resistance and salt and alkali resistance), and the comprehensive performance of the nitro fulvic acid is obviously superior to that of fulvic acid from coal sources. The paste byproduct is sent to a fertilizer factory to be used as a raw material for producing organic fertilizer and organic-inorganic compound fertilizer, and the yield and efficiency increasing effect of the paste byproduct is obviously better than that of coal-derived humic acid.

(5) Chemical and instrument analysis shows that the conversion rate of the cow dung nitro fulvic acid is more than 55%, the conversion rate of humic acid is more than 30%, and the total conversion rate is more than 85% (calculated on the dry matter of cow dung). The obtained nitrofulvic acid has a chemical structure similar to that of coal nitrofulvic acid, also has rich aromatic nucleus and active functional groups such as carboxyl, phenolic hydroxyl, nitro, quinonyl, carbonyl, methoxy and the like, and has good water solubility, metal complexation and electrolyte flocculation resistance. Through detection, the nitro fulvic acid solution of the invention: the pH value is 7-8.5, the content of nitrofulvic acid is more than or equal to 30%, the content of amino acid is more than or equal to 5%, the total content of nucleic acid, low-molecular organic acid, saccharide and inositol is more than or equal to 8%, the content of insoluble substances is less than or equal to 1%, and the condensation limit is more than or equal to 20 mmol/L; the total heavy metal content is less than or equal to 20mg/L, the detection rate of fecal escherichia coli is zero, and the death rate of ascarid eggs is more than or equal to 99 percent.

(6) The method for preparing the nitrofulvic acid by fermenting the cow dung has the advantages of small equipment investment, small occupied area, simple maintenance and low operation cost, and can be independently used for completing the preparation process. A discharge valve is specially arranged so as to check whether a semi-finished product in the preparation process meets the requirement, determine whether to continue preparation or readjust and the like; the slurry pump on the pipeline can pump the semi-finished product in the reaction kettle into the filter, and the filter is also specially provided with a 100-mesh and 200-mesh filter membrane; the arrangement ensures that the produced nitrofulvic acid can achieve higher conversion rate and yield.

Drawings

FIG. 1 is a process flow diagram for preparing nitrofulvic acid by fermenting cow dung according to the invention;

FIG. 2 shows the result of Fourier transform infrared spectroscopy analysis of the residue obtained in example 5;

FIG. 3 is a structural diagram of the equipment used for preparing nitrofulvic acid by fermenting cow dung.

1. A reaction kettle; 11. an inner layer; 12. a jacket; 13. a heating rod; 14. a stirring paddle 15 and a speed reducing motor; 16. A feeding port; 17. a water replenishing pipe; 18. a spray head; 2.a filter; 21. a discharge port; 3.a pipeline; 31. a discharge valve; 32. a slurry pump; 4. and (4) a bracket.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

As shown in figure 1, in some more specific embodiments, the method for preparing nitrofulvic acid by fermenting cow dung comprises the following steps:

(1) adding bran coats and humic acid into naturally air-dried cow dung to form a material to be fermented, and then inoculating brewing yeast for primary fermentation to form a primary fermented material; the adding amount ratio of the cow dung to the bran coat to the humic acid is 6-10:2-5: 1-3; adding 20-50kg of the brewing yeast into per cubic meter of the material to be fermented;

(2) inoculating the primary fermentation material in the step (1) with a complex microbial inoculum for secondary fermentation to form a secondary fermentation material; the complex microbial inoculum comprises bacillus, pseudomonas, thermophilic sporotrichum and rhizopus;

(3) adding nitric acid into the secondary fermentation material obtained in the step (2) for catalytic oxidation; adding alkaline substance for neutralization and extraction to obtain extract;

(4) and (4) carrying out solid-liquid separation and washing on the extract obtained in the step (3) to respectively obtain nitrofulvic acid liquid and a nitrohumic acid byproduct.

In a more specific embodiment, the method for preparing the nitrofulvic acid by fermenting the cow dung comprises the following steps:

(1) adding bran coats and humic acid into naturally air-dried cow dung to form a material to be fermented, wherein the addition amount of the humic acid is the amount of the humic acid, and then inoculating brewing yeast for primary fermentation to form a primary fermented material; the adding amount ratio of the cow dung to the bran coat to the humic acid is 6-10:2-5: 1-3; adding 20-50kg of the brewing yeast into per cubic meter of the material to be fermented; the brewing yeast is brewing yeast Hm, and the effective viable count of the brewing yeast is more than or equal to 8 multiplied by 10¹⁰Per gram; the bran coat is one of rice hull, wheat bran and sorghum hull; the humic acid is weathered coal powder, brown coal powder or coal humic acid powder with the content of more than or equal to 60 percent; the total humic acid and fulvic acid of the formed primary fermentation material are respectively more than or equal to 20 percent and more than or equal to 5 percent;

(2) inoculating the primary fermentation material in the step (1) with a complex microbial inoculum for secondary fermentation to form a secondary fermentation material; the composite microbial inoculum comprises bacillus megaterium T3, pseudomonas stutzeri B40, sporotrichum thermophilum Fie and rhizopus 7# with the ratio of viable count of 4-6:3-5:3-5: 1-3; the effective viable count of the composite microbial inoculum is more than or equal to 9 multiplied by 108/g; the addition amount of the complex microbial inoculum is 1-5% of the weight of the material to be fermented.

(3) Adding nitric acid into the secondary fermentation material obtained in the step (2) for catalytic oxidation; adding alkaline substance for neutralization and extraction to obtain extract; the catalyst is zinc sulfate, ferrous sulfate or sodium metavanadate;

(4) and (4) carrying out solid-liquid separation and washing on the extract obtained in the step (3) to respectively obtain nitrofulvic acid liquid and a nitrohumic acid byproduct.

The equipment for preparing the nitrofulvic acid by fermenting the cow dung comprises a reaction kettle and a filter, wherein the reaction kettle is connected with the filter through a pipeline; the reaction kettle comprises an inner layer and an outer sleeve, an interlayer space is arranged between the inner layer and the outer sleeve, and a heating rod is arranged in the interlayer space; a stirring paddle is arranged in the reaction kettle, and a speed reduction motor is arranged at the top of the reaction kettle; the reaction kettle is fixed on the bracket, and a discharge valve and a slurry pump are arranged on the pipeline; the lower part of the filter is provided with a discharge hole.