A preparation method of bio-organic fertilizer based on modified phosphate tailings

Abstract

This invention discloses a method for preparing bio-organic fertilizer based on modified phosphorus tailings, comprising the following steps: S1. Mixing phosphorus tailings, modified phosphorus tailings, kitchen waste, and / or plant straw, and / or poultry excrement to obtain a mixture, and then inoculating it with phosphorus-solubilizing microorganisms; S2. Fermenting to obtain a substrate; S3. Inoculating the fermented substrate with black soldier fly eggs, and then raising them to obtain black soldier fly larvae; S4. Separating the black soldier fly larvae and insect sand to obtain bio-organic fertilizer and black soldier fly larvae; wherein, the modification method of the modified phosphorus tailings is as follows: A1. Mixing phosphorus tailings and calcium oxide evenly, adding water, then adding hydrogen peroxide, generating bubbles and heating and stirring to form pellets, obtaining an intermediate product; A2. Drying and sintering the intermediate product to obtain modified phosphorus tailings. This invention uses a biological method to synergistically treat waste organic matter, which is highly efficient in treating phosphorus tailings and waste organic matter, safe and pollution-free, shortens the breeding cycle of black soldier flies, and obtains high-quality bio-organic fertilizer.

Description

Technical Field

[0001] This invention relates to the field of agricultural fertilizer production technology, specifically to a method for preparing bio-organic fertilizer based on modified phosphate tailings. Background Technology

[0002] Environmental governance and comprehensive resource utilization are receiving increasing attention, especially regarding tailings left over from large-scale mineral processing. These tailings are difficult to manage and, due to historical issues, accumulate in large quantities, posing significant safety hazards and causing subsequent surface and groundwater pollution. Currently, the situation regarding the disposal and comprehensive utilization of phosphate tailings is far from satisfactory, primarily relying on traditional methods of stockpiling and backfilling. Large amounts of tailings are piling up, failing to be effectively treated for a long time, placing significant pressure on treatment technology, costs, and space. With the progress of production and daily life, many types of organic waste are generated, including kitchen waste, agricultural waste, and livestock waste. These organic wastes are large in volume, pose significant social and environmental hazards, and have high treatment costs, attracting widespread attention from governments and researchers. If not treated promptly or properly, they will cause various environmental harms.

[0003] Phosphorus is an essential component of biomolecules such as DNA, RNA, ATP, and phosphate lipids, and a key substance for the growth and development of plants and animals. Insoluble phosphate tailings are difficult for plants and animals to absorb, but highly efficient and targeted phosphate-solubilizing microorganisms (PSMs) can largely convert insoluble inorganic phosphorus into water-soluble inorganic phosphorus, organic phosphorus, or microbial phosphorus. In existing technologies, phosphate-solubilizing organisms are added to phosphate tailings, followed by fermentation to release nutrients, with the products used as fertilizer or feed, thus improving the utilization rate of phosphate tailings. However, current processes still have relatively low utilization rates. Therefore, this invention improves upon existing technologies, developing a higher-utilization-rate and higher-quality organic fertilizer production process from phosphate tailings. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention develops a method for preparing bio-organic fertilizer based on modified phosphate tailings, comprising the following steps:

[0005] S1. Mix phosphorus tailings, modified phosphorus tailings, kitchen waste, and / or plant straw, and / or poultry excrement evenly to obtain a mixture, and then inoculate it with phosphorus-solubilizing microorganisms;

[0006] S2. Fermentation is carried out under specific temperature and humidity conditions to obtain the substrate;

[0007] S3. Black soldier fly eggs are inoculated onto the fermented substrate and then reared at a specific temperature and humidity to obtain black soldier fly larvae.

[0008] S4. Separate black soldier fly larvae and insect sand to obtain bio-organic fertilizer and black soldier fly larvae;

[0009] The modification method for the modified phosphate tailings is as follows:

[0010] A1. Mix phosphorus tailings and calcium oxide evenly, put them into water, then add hydrogen peroxide to generate bubbles and heat and stir. Then place them in a pelletizing machine to form pellets to obtain an intermediate product.

[0011] A2. The intermediate product is dried and sintered to obtain the modified phosphorus tailings, which have a porous structure.

[0012] Further, in step S1, the weight ratio of the phosphorus tailings, modified phosphorus tailings and the mixture is (1-5):(1-5):100.

[0013] Further, in step S1, the phosphorus-solubilizing microorganisms are selected from one or more of lactic acid bacteria, actinomycetes, Bacillus, and Kuterella.

[0014] Further, in step S1, the amount of phosphorus-solubilizing microorganisms added is 0.1 to 0.3% of the weight of the mixture.

[0015] Furthermore, in step S2, the fermentation period is 10 to 20 days.

[0016] Furthermore, in step S2, the specific temperature 1 is 25–35°C and the relative humidity is 70–90%.

[0017] Furthermore, in step S2, the number of days of rearing is 7 to 15 days.

[0018] Furthermore, in step S3, during the feeding process, the moisture content of the substrate is maintained at 65% to 75%.

[0019] Furthermore, in step S3, the specific temperature and humidity 2 are 25-35°C and relative humidity 50-90%.

[0020] Furthermore, in step A1, the concentration of the hydrogen peroxide is 20-35%.

[0021] Further, in step A1, the volume ratio of the water to the hydrogen peroxide is (30-60):1.

[0022] Further, in step A1, the weight ratio of the phosphorus tailings to calcium oxide is (5-20):1.

[0023] Furthermore, in step A1, the heating temperature is 40–80°C.

[0024] Furthermore, in step A1, the diameter of the intermediate product is controlled within the range of 0.5 to 5 mm.

[0025] Further, in step A2, the sintering conditions are: preheating temperature 300-500℃, preheating time 40-120min, sintering temperature 800-1100℃, and sintering time 40-120min.

[0026] The present invention has the following beneficial effects:

[0027] (1) This invention employs the introduction of exogenous microorganisms to promote the co-fermentation of formulated amounts of phosphorus tailings, modified phosphorus tailings, and kitchen waste, agricultural waste, and livestock waste. Under sufficient nutrient conditions, the microorganisms multiply, transforming lignin, cellulose, and hemicellulose in the organic waste into sugars, organic acids, amino acids, peptides, and phenols. Simultaneously, it promotes the reproduction of phosphorus-solubilizing microorganisms, efficiently converting phosphorus in the phosphorus tailings. Finally, the fermentation products of the organic waste and modified phosphorus tailings are transformed by insects, achieving efficient conversion and utilization of multiple elements including carbon, nitrogen, and phosphorus. Moreover, phosphorus, as a nutrient element, will inevitably promote the growth and development of microorganisms in black soldier fly larvae and insect sand, shortening the breeding cycle of black soldier fly larvae, thereby reducing breeding costs and improving the quality of black soldier fly products.

[0028] (2) This invention modifies phosphorus tailings to form a porous structure. This porous structure promotes the colonization of phosphorus-solubilizing microorganisms, providing them with more habitat and growth space, which is beneficial for their growth and reproduction, and improves the utilization rate of insoluble phosphorus. Simultaneously, it increases surface area and porosity, enhancing the effectiveness of the phosphorus tailings and making the phosphorus more readily available for utilization by these microorganisms. When phosphorus-solubilizing microorganisms colonize the porous phosphorus tailings, they can convert inorganic phosphorus into organic phosphorus or soluble inorganic phosphorus through the secretion of acids, enzymes, etc. The porous structure also increases the aeration and moisture retention capacity of the substrate, further facilitating the growth and activity of phosphorus-solubilizing microorganisms. Therefore, the treatment method of this invention achieves efficient disposal of phosphorus tailings and uses a biological method to co-treat waste organic matter. This method is highly efficient, safe, and pollution-free in treating phosphorus tailings and waste organic matter, shortens the breeding cycle of black soldier flies, and yields high-quality functional bio-organic fertilizer rich in P, Ca, and Mg elements, as well as economically valuable insects rich in P, Ca, Mg, and nutrients such as protein and oil. This treatment method is simple and feasible, and can be used for large-scale corporate processing as well as small-scale individual farming. It provides new ideas for enterprises to efficiently dispose of and utilize tailings resources and waste organic matter, and also provides a feasible implementation path for building beautiful villages and revitalizing rural areas. Detailed Implementation

[0029] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0030] The modified phosphate tailings in the embodiments of this invention were all prepared using the following method:

[0031] A1. Mix phosphorus tailings and calcium oxide (both with an average particle size of 0.09 mm and a weight ratio of 10:1) evenly, add water (the amount of water is 10% of the total weight of phosphorus tailings and calcium oxide), then add 30% hydrogen peroxide (the volume ratio of water to hydrogen peroxide is 40:1), generate bubbles, heat to 70°C and stir, then place in a pelletizer to form pellets, to obtain an intermediate product with a diameter of 1-3 mm;

[0032] A2. The intermediate product was placed in a drying oven and dried at 100°C for 1 hour. After drying, it was placed in a box-type resistance furnace and sintered at a preheating temperature of 350°C for 10 minutes, a sintering temperature of 1000°C, and a sintering time of 60 minutes to obtain modified phosphorus tailings, which have a porous structure.

[0033] Example 1

[0034] A method for preparing bio-organic fertilizer based on modified phosphate tailings, comprising the following steps:

[0035] S1. Mix 45g of phosphorus tailings (particle size ≤200 mesh), 30g of modified phosphorus tailings, 680g of kitchen waste, and 245g of corn stalks evenly to obtain a mixture, and then inoculate 2.5g of phosphorus-solubilizing microorganisms.

[0036] S2. The mixture is fermented at 28°C and 80% humidity for 15 days to obtain the base material;

[0037] S3. Take 0.5g of black soldier fly eggs, emulsify them with wheat bran, and then transfer them to the above-mentioned substrate for rearing. Control the moisture content of the substrate to about 70% by adding water. Rearing is carried out for 12 days under the conditions of ambient temperature of 28℃ and humidity of 70%.

[0038] S4. Separate the black soldier fly larvae and insect sand, and harvest the organic fertilizer and black soldier fly larvae.

[0039] Example 2

[0040] A method for preparing bio-organic fertilizer based on modified phosphate tailings, comprising the following steps:

[0041] S1. Mix 40g of phosphorus tailings (particle size ≤200 mesh), 20g of modified phosphorus tailings, 520g of kitchen waste, and 420g of fresh chicken manure evenly to obtain a mixture, and then inoculate 2.5g of phosphorus-solubilizing microorganisms.

[0042] S2. The mixture is fermented at 30°C and 75% humidity for 20 days to obtain the base material;

[0043] S3. Take 0.5g of black soldier fly eggs, emulsify them with wheat bran, and then transfer them to the above-mentioned substrate for rearing. Control the moisture content of the substrate to about 70% by adding water. Rearing is carried out for 12 days under the conditions of ambient temperature of 30℃ and humidity of 70%.

[0044] S4. Separate the black soldier fly larvae and insect sand, and harvest the organic fertilizer and black soldier fly larvae.

[0045] Example 3

[0046] A method for preparing bio-organic fertilizer based on modified phosphate tailings, comprising the following steps:

[0047] S1. Mix 40g of phosphorus tailings (particle size ≤200 mesh), 15g of modified phosphorus tailings, 395g of kitchen waste, 200g of corn stalks, and 350g of fresh chicken manure evenly to obtain a mixture, and then inoculate 2.5g of phosphorus-solubilizing microorganisms.

[0048] S2. The mixture is fermented at 30°C and 75% humidity for 15 days to obtain the base material;

[0049] S3. Take 0.5g of black soldier fly eggs, emulsify them with wheat bran, and then transfer them to the above-mentioned substrate for rearing. Control the moisture content of the substrate to about 70% by adding water. Rearing is carried out for 12 days under the conditions of ambient temperature of 30℃ and humidity of 70%.

[0050] S4. Separate the black soldier fly larvae and insect sand, and harvest the organic fertilizer and black soldier fly larvae.

[0051] Comparative Example 1

[0052] A method for preparing organic fertilizer, wherein the method for preparing organic fertilizer described in Comparative Example 2 is the same as that in Example 1, the only difference being that Comparative Example 2 does not contain modified phosphate tailings, but instead contains an equal weight of unmodified phosphate tailings.

[0053] Test Case

[0054] (1) Various indicators of Examples 1-3, Comparative Example 1 and commercially available organic fertilizer were measured, and the results are shown in Table 1.

[0055] Table 1. Comparison of various indicators between Examples 1-3, Comparative Example 1, and commercially available organic fertilizer.

[0056]

[0057]

[0058] As can be seen from Table 1, the phosphorus content of the organic fertilizer in Example 1 of this invention is higher than that in Comparative Example 1, and the contents of organic matter, potassium, and nitrogen are also significantly higher than those in Comparative Example 1. The contents of soluble calcium and magnesium are also higher than those in Comparative Example 1, while the heavy metal content is not significantly different from that in Comparative Example 1.

[0059] (2) Various indicators of the black soldier fly larvae obtained in Examples 1-3 and Comparative Example 1 were measured. Fifty black soldier fly larvae were taken, cleaned, and dried, and their average body length and weight were measured. The breeding environment of the black soldier fly larvae was room temperature 25℃ and humidity 60-80%. The results are shown in Table 2.

[0060] Table 2 Comparison of various indicators of black soldier fly larvae in Examples 1-3 and Comparative Example 1

[0061] Experiment number Example 1 Example 2 Example 3 Comparative Example 1 Average life cycle of black soldier fly larvae 7 7 8 9 Average weight (black soldier fly larvae) / g 0.153 0.147 0.141 0.132 Average body length (black soldier fly larva) / mm 19 18 18 16 P content in black soldier fly larvae / % 0.175 0.162 0.158 0.151 Ca content in black soldier fly larvae / % 0.077 0.068 0.065 0.064 Mg content in black soldier fly larvae / % 0.016 0.014 0.010 0.011

[0062] As can be seen from Table 2, the harvest period of black soldier fly larvae raised in the fermentation substrate of Examples 1-3 of the present invention was significantly shorter than that of Comparative Example 1. The weight and body length of the larvae raised in Example 1 were significantly increased compared with those of the Comparative Example. Moreover, the content of elements such as phosphorus, calcium and magnesium in the black soldier fly larvae of Example 1 was significantly higher than that of the Comparative Example.

[0063] (3) In accordance with the requirements of the "Technical Specifications for Chili Pepper Planting", the organic fertilizers obtained in Examples 1-3 and Comparative Example 1 were used as fertilizers, and a blank group (no fertilizer was used) was set up. Ten chili pepper plants were planted in each group, and then various indicators of the chili peppers were measured. The results are shown in Table 3.

[0064] Table 3 Comparison of various indicators of chili peppers

[0065]

[0066]

[0067] As can be seen from Table 3, the comparison of chili pepper planting experiments also shows that the plant height of chili peppers planted with the organic fertilizer of Example 1 is significantly higher than that of the control group and the blank group, and the flowering time, flowering quantity and fruit yield are also significantly better than those of the control group and the blank group.

[0068] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0069] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing bio-organic fertilizer based on modified phosphate tailings, characterized in that, The method for preparing bio-organic fertilizer based on modified phosphate tailings includes the following steps: S1. Mix phosphorus tailings, modified phosphorus tailings, kitchen waste, and / or plant straw, and / or poultry excrement evenly to obtain a mixture, and then inoculate it with phosphorus-solubilizing microorganisms; S2. Fermentation is carried out under specific temperature and humidity conditions to obtain the substrate; S3. Black soldier fly eggs are inoculated onto the fermented substrate and then reared at a specific temperature and humidity to obtain black soldier fly larvae. S4. Separate black soldier fly larvae and insect sand to obtain bio-organic fertilizer and black soldier fly larvae; The modification method for the modified phosphate tailings is as follows: A1. Mix phosphorus tailings and calcium oxide evenly, put them into water, then add hydrogen peroxide, generate bubbles, heat and stir to form pellets, and obtain intermediate product; A2. The intermediate product is dried and sintered to obtain the modified phosphate tailings; In step A1, the concentration of the hydrogen peroxide is 20-35%; In step A1, the heating temperature is 40–80°C.

2. The method for preparing bio-organic fertilizer based on modified phosphate tailings according to claim 1, characterized in that, In step S1, the phosphorus-solubilizing microorganisms are selected from one or more of lactic acid bacteria, actinomycetes, Bacillus, and Kuterella.

3. The method for preparing bio-organic fertilizer based on modified phosphate tailings according to claim 1, characterized in that, In step S1, the weight ratio of the phosphorus tailings, modified phosphorus tailings and the mixture is (1-5):(1-5):

100.

4. The method for preparing bio-organic fertilizer based on modified phosphate tailings according to claim 1, characterized in that, In step S2, the fermentation period is 10 to 20 days.

5. The method for preparing bio-organic fertilizer based on modified phosphate tailings according to claim 1, characterized in that, In step S2, the specific temperature 1 is 25-35°C and the relative humidity is 70-90%.

6. The method for preparing bio-organic fertilizer based on modified phosphate tailings according to claim 1, characterized in that, In step S3, during the feeding process, the moisture content of the substrate is maintained at 65% to 75%.

7. The method for preparing bio-organic fertilizer based on modified phosphate tailings according to claim 1, characterized in that, In step S3, the specific temperature and humidity 2 are 25-35°C and 50-90% relative humidity.

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