Loss-preventing slow-release fertilizer and preparation method thereof

Abstract

The invention discloses a preparation method of an anti-loss slow-release fertilizer, which comprises the following steps: (1) protein modification: adding a phosphoric acid aqueous solution and sodium tripolyphosphate into biomass protein, uniformly stirring, then carrying out heating reaction, and after the reaction is completed, cooling to room temperature to obtain a modified protein mixture; (2) coating: putting the fertilizer into a rotary drum granulator for granulation treatment, spraying the modified protein mixture on the surface of the fertilizer for coating treatment in a rotating state of the rotary drum granulator after the fertilizer is granulated, and drying after the fertilizer is coated, so as to obtain the anti-loss slow-release fertilizer. According to the fertilizer disclosed by the invention, the biomass protein is used for coating the fertilizer, so that the effect of improving the fertility of the fertilizer is achieved, the biomass protein is modified by phosphoric acid, the modified biomass protein has compactness, and phosphoric acid residues can be combined with calcium and magnesium elements in soil through chemical bonds, so that the binding force of the fertilizer and the soil can be improved, and the effect of preventing loss is achieved.

Description

Technical Field

[0001] The invention relates to the field of fertilizers, and in particular to an anti-loss slow-release fertilizer and a preparation method thereof. Background Art

[0002] With the development of agricultural technology, a new type of fertilizer has emerged - slow-release fertilizer. Slow-release fertilizer is a traditional fertilizer particle wrapped with a layer of film (such as protein film, polymer film, etc.) that can control the rate and amount of nutrient release. It can gradually release nutrients according to the nutrient demand of crop growth.

[0003] However, there is another problem with the use of slow-release fertilizers. That is, after the fertilizer is applied, in rainy weather, especially when there is heavy rainfall, the rainwater will wash away the fertilizer particles as it flows through the soil and is lost with the rainwater, resulting in low fertilizer utilization. Summary of the invention

[0004] The main purpose of the present invention is to provide a loss-proof slow-release fertilizer and a preparation method thereof.

[0005] To achieve the above object, the present invention provides a method for preparing an anti-loss slow-release fertilizer, comprising the following steps:

[0006] (1) Protein modification

[0007] Adding phosphoric acid aqueous solution and sodium tripolyphosphate to the biomass protein, stirring evenly, and then heating to react, and after the reaction is completed, cooling to room temperature to obtain a modified protein mixture;

[0008] (2) Encapsulation

[0009] The fertilizer is put into a drum granulator for granulation. After the fertilizer is granulated, the modified protein mixture is sprayed on the surface of the fertilizer for coating while the drum granulator is rotating. After the fertilizer is coated, it is dried to obtain the anti-loss slow-release fertilizer.

[0010] Furthermore, the biomass protein is keratin or collagen.

[0011] Furthermore, in step (1), the concentration of the phosphoric acid aqueous solution is 5-10wt%, and the amount of the phosphoric acid aqueous solution is 3-8 parts by weight, the amount of sodium tripolyphosphate is 8-20 parts by weight, and the amount of biomass protein is 75-90 parts by weight. If the amount of sodium tripolyphosphate is too low, the phosphating effect is not good. If the amount is too high, it will be lost in water and the cost is high. It has been verified that the above ratio is set to have a better comprehensive effect.

[0012] Furthermore, in step (1), the heating reaction conditions are a temperature of 20 to 80° C. and a reaction time of 3 to 6 hours.

[0013] Furthermore, the fertilizer is any one of nitrogen fertilizer, phosphorus fertilizer, potash fertilizer, urea, and compound fertilizer, or a mixture of two or more thereof.

[0014] Furthermore, in step (2), the fertilizer is obtained by mixing nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer and stirring at 80 to 105° C. for 30 to 50 minutes.

[0015] Furthermore, in step (2), the particle size of the particles after granulation treatment is 2 to 3 mm.

[0016] Furthermore, in step (2), the amount of the modified protein mixture added is 3-5% of the total amount of the fertilizer, the speed of the coating-treated drum granulator is 10-12 r / min, and the time is 15-50 minutes.

[0017] Furthermore, in step (2), the drying treatment conditions are a temperature of 105 to 110° C. and a drying time of 3 to 5 hours.

[0018] The present invention also provides an anti-loss slow-release fertilizer, which is prepared according to the above preparation method.

[0019] The beneficial effects of the present invention are embodied in:

[0020] The fertilizer coating of the present invention uses biomass protein, which contains various other amino acids such as serine and has the effect of enhancing the fertility of chemical fertilizers.

[0021] The invention uses phosphoric acid to modify biomass protein, and the carboxyl group and amide group in the protein undergo esterification reaction with the phosphoric acid. The addition of sodium tripolyphosphate can enhance the phosphating effect and make the reaction more complete. The modified biomass protein has compactness, is not easy to be hydrolyzed in moist soil, has better slow-release effect, and the phosphoric acid residue can be combined with calcium and magnesium elements in the soil by chemical bonds, thereby improving the binding force between the fertilizer and the soil and preventing loss. In addition, phosphoric acid cannot be used alone as a fertilizer, but after phosphoric acid reacts with the protein, it can be used as a fertilizer, thereby increasing the phosphorus content of the fertilizer and having the effect of enhancing the fertility of the fertilizer. DETAILED DESCRIPTION

[0022] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be noted that the following embodiments do not limit the protection scope of the present invention.

[0023] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial channels or by existing known methods; unless otherwise specified, the methods used in the embodiments of the present invention are methods known to those skilled in the art. Among them, porcine collagen was purchased from Hubei Langbowan Biomedicine Co., Ltd., and urea was purchased from Anqing Petrochemical.

[0024] Example 1

[0025] Preparation of anti-loss slow-release fertilizer

[0026] (1) Protein modification

[0027] Adding phosphoric acid aqueous solution and sodium tripolyphosphate to porcine collagen, wherein the concentration of the phosphoric acid aqueous solution is 8wt%, and the amount of the phosphoric acid aqueous solution is 6 parts, the amount of the sodium tripolyphosphate is 15 parts, and the amount of the biomass protein is 80 parts, and the above mixture is stirred evenly, and then reacted at a temperature of 50° C. for 5 hours. After the reaction is completed, cooling to room temperature to obtain a modified protein mixture;

[0028] (2) Encapsulation

[0029] Urea was put into a drum granulator and granulated at a speed of 20 r / min to obtain fertilizer particles with a particle size of 3 mm. The drum granulator was kept rotating, and a modified protein mixture accounting for 4% of the total amount of the fertilizer was sprayed on the surface of the fertilizer. The fertilizer was then treated at a speed of 10 r / min for 40 minutes to coat the fertilizer. Finally, it was dried at a temperature of 105°C for 5 hours to obtain an anti-loss slow-release fertilizer.

[0030] Example 2

[0031] Preparation of anti-loss slow-release fertilizer

[0032] (1) Protein modification

[0033] Adding phosphoric acid aqueous solution and sodium tripolyphosphate to porcine collagen, wherein the concentration of the phosphoric acid aqueous solution is 5wt%, and the amount of the phosphoric acid aqueous solution is 8 parts, the amount of the sodium tripolyphosphate is 20 parts, and the amount of the biomass protein is 90 parts, and the above mixture is stirred evenly, and then reacted at a temperature of 20° C. for 6 hours. After the reaction is completed, the mixture is cooled to room temperature to obtain a modified protein mixture;

[0034] (2) Encapsulation

[0035] Urea was put into a drum granulator and granulated at a speed of 15 r / min to obtain fertilizer particles with a particle size of 2 mm. The drum granulator was kept rotating, and a modified protein mixture accounting for 5% of the total amount of the fertilizer was sprayed on the surface of the fertilizer. The fertilizer was then treated at a speed of 12 r / min for 15 minutes to coat the fertilizer. Finally, it was dried at 110°C for 3 hours to obtain an anti-loss slow-release fertilizer.

[0036] Example 3

[0037] Preparation of anti-loss slow-release fertilizer

[0038] (1) Protein modification

[0039] Adding phosphoric acid aqueous solution and sodium tripolyphosphate to porcine collagen, wherein the concentration of the phosphoric acid aqueous solution is 10wt%, and the amount of the phosphoric acid aqueous solution is 3 parts, the amount of the sodium tripolyphosphate is 8 parts, and the amount of the biomass protein is 75 parts, and the above mixture is stirred evenly, and then reacted at a temperature of 80° C. for 3 hours. After the reaction is completed, cooling to room temperature to obtain a modified protein mixture;

[0040] (2) Encapsulation

[0041] Urea was put into a drum granulator and granulated at a speed of 20 r / min to obtain fertilizer particles with a particle size of 3 mm. The drum granulator was kept rotating, and a modified protein mixture accounting for 3% of the total amount of the fertilizer was sprayed on the surface of the fertilizer. Then, the fertilizer was treated at a speed of 10 r / min for 50 minutes to coat the fertilizer. Finally, it was dried at a temperature of 105°C for 5 hours to obtain an anti-loss slow-release fertilizer.

[0042] Comparative Example 1

[0043] This comparative example was operated according to the method of Example 1, except that the phosphoric acid aqueous solution was omitted.

[0044] Comparative Example 2

[0045] This comparative example was operated according to the method of Example 1, except that sodium tripolyphosphate was omitted.

[0046] Comparative Example 3

[0047] This comparative example was operated according to the method of Example 1, except that the phosphoric acid aqueous solution and sodium tripolyphosphate were omitted.

[0048] Testing the slow-release effect of fertilizers

[0049] The slow-release performance of the fertilizers prepared in the above-mentioned embodiments and comparative examples was tested in accordance with GBT23348-2009, and the release characteristics of nitrogen were used as the nutrient release characteristics of the fertilizer. The results are shown in Table 1 below.

[0050] Table 1 Nitrogen content release data of fertilizer (urea)

[0051]

[0052] It can be seen from the above that the fertilizers prepared in the embodiments of the present invention have good slow-release properties, while the comparative examples have no modification or poor modification effect, and the density of the protein film is not high, making the biomass protein easy to release.

[0053] Fertilizer loss prevention effect detection

[0054] The calcium content in the test soil is 345 mg / kg, and the magnesium content is 56 mg / kg. A rectangular container with a side length of 15 cm and a height of 10 cm is used for the test. A horizontal opening with a length of 10 cm and a width of 1 cm is opened at the bottom of one side wall of the container. The fertilizer and soil are evenly mixed in a ratio of 0.5:10 and filled into the container (the amount of fertilizer and soil used in each group of experiments is the same). Then, 1500 ml of pure water is used to elute the soil at a rate of 50 ml / min. A measuring cup is used to receive the eluent flowing out of the horizontal opening. Finally, the fertilizer content in the eluent is tested, and the fertilizer loss rate is calculated. The loss rate = the mass of fertilizer in the eluent ÷ the original mass of fertilizer. The results are shown in Table 2 below.

[0055] Table 2 Fertilizer loss rate

[0056] sample Churn rate Example 1 13％ Example 2 28％ Example 3 39％ Comparative Example 1 52％ Comparative Example 2 68％ Comparative Example 3 82％

[0057] As can be seen from the above table, the fertilizers prepared in various embodiments of the present invention have a low loss rate after water rinsing, while the comparative example 1 has a poor modification effect due to the lack of phosphoric acid modification, the comparative example 2 has an even worse modification effect due to the lack of sodium tripolyphosphate during modification, and the comparative example 3 has the worst effect due to the lack of phosphorus-based modification.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an anti-loss slow-release fertilizer, characterized in that: The following steps are involved: (1) Protein modification Adding phosphoric acid aqueous solution and sodium tripolyphosphate to the biomass protein, stirring evenly, and then heating to react, and after the reaction is completed, cooling to room temperature to obtain a modified protein mixture; (2) Encapsulation The fertilizer is put into a drum granulator for granulation. After the fertilizer is granulated, the modified protein mixture is sprayed on the surface of the fertilizer for coating while the drum granulator is rotating. After the fertilizer is coated, it is dried to obtain the anti-loss slow-release fertilizer.

2. The method for preparing the anti-loss slow-release fertilizer according to claim 1, characterized in that: The biomass protein is keratin or collagen.

3. The method for preparing the anti-loss slow-release fertilizer according to claim 1 or 2, characterized in that: In step (1), the concentration of the phosphoric acid aqueous solution is 5-10wt%, and the amount of the phosphoric acid aqueous solution is 3-8 parts by weight, the amount of sodium tripolyphosphate is 8-20 parts by weight, and the amount of biomass protein is 75-90 parts by weight.

4. The method for preparing the anti-loss slow-release fertilizer according to claim 1 or 2, characterized in that: In step (1), the heating reaction conditions are a temperature of 20 to 80° C. and a reaction time of 3 to 6 hours.

5. The method for preparing the anti-loss slow-release fertilizer according to claim 1 or 2, characterized in that: In step (2), the fertilizer is any one of nitrogen fertilizer, phosphorus fertilizer, potash fertilizer, and urea, or a mixture of two or more thereof.

6. The method for preparing the anti-loss slow-release fertilizer according to claim 1 or 2, characterized in that: In step (2), the fertilizer is obtained by mixing nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer and stirring them at 80-105° C. for 30-50 minutes.

7. The method for preparing the anti-loss slow-release fertilizer according to claim 1 or 2, characterized in that: In step (2), the particle size of the granules after granulation treatment is 2 to 3 mm.

8. The method for preparing the anti-loss slow-release fertilizer according to claim 1 or 2, characterized in that: In step (2), the amount of the modified protein mixture added is 3-5% of the total amount of the fertilizer, the speed of the coating-treated drum granulator is 10-12 r / min, and the time is 15-50 minutes.

9. The method for preparing the anti-loss slow-release fertilizer according to claim 1 or 2, characterized in that: In step (2), the drying conditions are a temperature of 105 to 110° C. and a drying time of 3 to 5 hours.

10. An anti-loss slow-release fertilizer, characterized in that: It is prepared according to the preparation method according to any one of claims 1 to 9.

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