Method for preparing agricultural fertilizer from amino acid type ammonium sulfate crystallization mother liquor

Abstract

The invention relates to the technical field of agricultural fertilizers, in particular to a method for preparing an agricultural fertilizer from amino acid type ammonium sulfate crystallization mother liquor, which comprises the following steps: concentrating and drying the amino acid type ammonium sulfate crystallization mother liquor, mixing with a nitrogen-phosphorus-potassium compound fertilizer, an organic matter carrier, a trace element additive and a functional aid in proportion, and granulating. Industrial by-products are used as core raw materials, efficient synergism of nutrients is achieved by optimizing the process, the quick-acting and long-acting characteristics are achieved, the yield and quality of crops are remarkably improved, and meanwhile environmental pollution is reduced. The method is simple in process, low in cost, remarkable in environmental protection benefit and suitable for various crop planting scenes, and technical support is provided for agricultural green sustainable development.

Description

Technical Field

[0001] This invention belongs to the field of agricultural fertilizer technology, specifically a method for preparing agricultural fertilizer from amino acid-type ammonium sulfate crystallization mother liquor. Background Technology

[0002] Currently, agricultural fertilizers largely rely on traditional chemical synthesis processes, leading to problems such as soil structure degradation and nutrient imbalance after long-term use. Continued use of such fertilizers will degrade crop quality and burden the ecological environment. Furthermore, the resource utilization rate of industrial byproducts, such as amino acid-based ammonium sulfate crystallization mother liquor, is low, failing to fully tap its potential rich in amino acids and various nutrients, thus hindering the high-value utilization of agricultural waste.

[0003] A search revealed that patent CN104311337B relates to a method for producing liquid fertilizer from glutamic acid wastewater, achieving resource utilization through steps such as fermentation broth filtration, decolorization, and concentration. However, this method only focuses on the separation of ammonium sulfate, failing to fully integrate amino acids and other nutrients in the mother liquor, thus limiting the overall performance of the fertilizer product. Furthermore, the stringent wastewater pretreatment requirements increase energy consumption and cost, hindering its widespread application.

[0004] Another patent, CN101913957B, discloses a technology for preparing insect-repellent organic-inorganic compound fertilizer from tobacco waste. This method diversifies fertilizer functions by mixing tobacco waste with raw materials such as ammonium sulfate. However, this method has limited efficiency in converting proteins into amino acids, failing to fully utilize the growth-promoting effects of amino acids on crops. Furthermore, the extensive methods of treating organic waste may result in residual harmful substances, further impacting the safety and environmental friendliness of the fertilizer.

[0005] Therefore, how to optimize the resource utilization of amino acid-type ammonium sulfate crystallization mother liquor, enhance the synergistic effect of organic components and nutrients in fertilizers, and reduce energy consumption and environmental burden in the production process has become an urgent problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a process for preparing agricultural fertilizer based on amino acid-type ammonium sulfate crystallization mother liquor, so as to solve the problems of single fertilizer nutrients, complex process, insufficient environmental friendliness, and low degree of resource utilization of industrial by-products in the prior art.

[0007] This invention provides a method for preparing agricultural fertilizer from amino acid-type ammonium sulfate crystallization mother liquor, comprising the following steps: S1: Concentrating the amino acid-type ammonium sulfate crystallization mother liquor using a single-effect or quadruple-effect concentrator to reduce the volume of the mother liquor to 1 / 16 to 1 / 20 of its original volume; S2: Converting the concentrated mother liquor into a solid powder base material using a spray drying device; S3: Mixing nitrogen, phosphorus, and potassium compound fertilizer, organic matter carrier, trace element additives, and functional auxiliaries uniformly according to a weight ratio to form an auxiliary material mixture; S4: Injecting the dried mother liquor base material and the auxiliary material mixture into a twin-shaft mixer for thorough mixing; S5: Granulating the mixture using a granulator and then performing low-temperature drying in a blower drying device to obtain the finished fertilizer.

[0008] Preferably, the fertilizer is made from the following components in the following weight ratio: 500-600 parts of amino acid-type ammonium sulfate crystallization mother liquor, 200-300 parts of nitrogen-phosphorus-potassium compound fertilizer, 100-150 parts of organic matter carrier, 5-10 parts of trace element additives, and 3-8 parts of functional adjuvants; the nutrient ratio of the nitrogen-phosphorus-potassium compound fertilizer is N-P2O5-K2O=15-15-15 to 20-10-20; the organic matter carrier is one or more of humic acid and straw powder; the trace element additives are a mixture of zinc sulfate, copper sulfate, and boric acid; and the functional adjuvants are chitosan or sodium alginate.

[0009] Preferably, the fertilizer is made from the following components in the following weight ratio: 550 parts of amino acid-type ammonium sulfate crystal mother liquor, 250 parts of nitrogen, phosphorus and potassium compound fertilizer, 120 parts of organic matter carrier, 7 parts of trace element additives and 5 parts of functional adjuvants.

[0010] Preferably, the evaporation temperature of the concentration process is 60-80℃, and the vacuum degree is -0.08 to -0.09 MPa.

[0011] Preferably, the inlet air temperature of the spray drying equipment is 180-200℃, the outlet air temperature is 80-90℃, and the spray disc rotation speed is 12000-15000 revolutions per minute.

[0012] Preferably, the mixing time of the auxiliary material mixture is 15-20 minutes and the rotation speed is 30-40 r / min.

[0013] Preferably, the mixing time of the twin-shaft mixer is 25-30 minutes, and the rotation speed is 20 to 25 r / min.

[0014] Preferably, the granulator speed in the granulation process is 20-25 r / min, and the tilt angle is 45-50 degrees.

[0015] Preferably, the drying temperature of the blower drying equipment is 60-70℃ and the drying time is 30-40 minutes.

[0016] Preferably, the particle size of the finished fertilizer is 2-4 mm.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) This invention uses amino acid-type ammonium sulfate crystallization mother liquor, a byproduct of amino acid fermentation wastewater treatment, as the core raw material, realizing the high-value utilization of industrial waste and constructing a closed-loop model of "wastewater-resource-fertilizer".

[0019] (2) The present invention simplifies the mother liquor treatment process through concentration and drying processes, reduces energy consumption and production costs, and avoids the environmental pollution problems caused by traditional spray granulation process.

[0020] (3) The fertilizer formula of this invention takes into account both rapid and long-term effects. It can meet the rapid nutrient needs of crops in the early stage of growth and continuously supply the nutrients needed in the middle and late stages. It is suitable for planting scenarios of various crops.

[0021] (4) This invention reduces the amount of fertilizer used, reduces agricultural non-point source pollution, meets the national policy requirement of "zero growth in fertilizer use", and promotes green and sustainable agricultural development. Attached Figure Description

[0022] Figure 1 This is a flowchart of the preparation method for agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to the present invention. Detailed Implementation

[0023] The process flow diagram of the "Method for Preparing Agricultural Fertilizer from Amino Acid Type Ammonium Sulfate Crystallization Mother Liquor" provided by this invention is as follows: Figure 1 As shown, the main processes include mother liquor concentration, spray drying, auxiliary material mixing, biaxial stirring, granulation and drying, etc. The resource utilization of industrial by-products is achieved through parameter optimization of each step.

[0024] Example 1

[0025] S1. Raw material preparation: Take 550 parts of amino acid type ammonium sulfate crystallization mother liquor (COD=50000mg / L, amino acid content 8%), 250 parts of nitrogen-phosphorus-potassium compound fertilizer (N-P2O5-K2O=18-12-20), 120 parts of organic matter carrier (humic acid), 7 parts of trace element additive (zinc sulfate: copper sulfate: boric acid=3:2:1), and 5 parts of functional aid (chitosan).

[0026] S2. Concentration treatment: The mother liquor is put into a four-effect concentration device, the evaporation temperature is 70℃, the vacuum degree is -0.085MPa, and it is concentrated to 1 / 18 of the original volume to obtain concentrated liquid.

[0027] S3. Spray drying: Using spray drying equipment, the inlet air temperature is 190℃, the outlet air temperature is 85℃, and the spray disc speed is 13000 rpm, the concentrated liquid is converted into solid powder base material.

[0028] S4. Additive Mixing: Add nitrogen, phosphorus and potassium compound fertilizer, organic matter carrier, trace element additives and functional auxiliaries into a horizontal mixer and mix at a speed of 35 r / min for 18 minutes to form an additive mixture.

[0029] S5. Twin-shaft mixing: The dried mother liquor base material and auxiliary material mixture are put into a twin-shaft mixer and mixed at a speed of 22r / min for 28 minutes.

[0030] S6. Granulation and Drying: Granules are formed by granulation using a granulator (22 r / min, 48 degrees inclination), and then dried at 65°C for 35 minutes in a blower drying equipment to obtain finished fertilizer with a particle size of 2-4 mm.

[0031] Example 2

[0032] Unlike Example 1:

[0033] 1. The amount of amino acid-type ammonium sulfate crystallization mother liquor used is 500 parts, nitrogen, phosphorus and potassium compound fertilizer is 300 parts, and organic matter carrier is 100 parts.

[0034] 2. Concentrate to 1 / 16 of the original volume, evaporation temperature 60℃, vacuum degree -0.08MPa.

[0035] 3. Spray drying inlet air temperature 180℃, outlet air temperature 80℃, spray disc rotation speed 12000 rpm.

[0036] 4. Mixing time for auxiliary materials: 15 minutes, speed: 30 r / min; mixing time for dual-shaft mixing: 25 minutes, speed: 20 r / min.

[0037] 5. Granulator tilt angle 45 degrees, forced air drying temperature 60℃, drying time 40 minutes.

[0038] Example 3

[0039] Unlike Example 1:

[0040] 1. The dosage of amino acid-type ammonium sulfate crystallization mother liquor is 600 parts, nitrogen, phosphorus and potassium compound fertilizer is 200 parts, organic matter carrier is 150 parts, trace element additive is 10 parts, and functional additive is 8 parts.

[0041] 2. Concentrate to 1 / 20 of the original volume, evaporation temperature 80℃, vacuum degree -0.09MPa.

[0042] 3. Spray drying inlet air temperature 200℃, outlet air temperature 90℃, spray disc rotation speed 15000 rpm.

[0043] 4. Mixing time for auxiliary materials: 20 minutes, speed: 40 r / min; mixing time for dual-shaft mixing: 30 minutes, speed: 25 r / min.

[0044] 5. Granulator speed 25r / min, tilt angle 50 degrees, forced air drying temperature 70℃, drying time 30 minutes.

[0045] Comparative Example 1

[0046] Unlike Example 1, no amino acid-type ammonium sulfate crystallization mother liquor was added; instead, an equal amount of industrial ammonium sulfate (containing 21% nitrogen) was used. The amounts of other raw materials and the preparation method were the same as in Example 1.

[0047] Comparative Example 2

[0048] Unlike Example 1, no trace element additives were added, but the amounts of other raw materials and the preparation method were the same as in Example 1.

[0049] Comparative Example 3

[0050] Commercially available ordinary compound fertilizer (N-P2O5-K2O=15-15-15) was used, without the use of amino acid-type ammonium sulfate crystallization mother liquor or the process of this invention.

[0051] The following experiments were conducted for the above embodiments:

[0052] I. Nutrient Content Test

[0053] 1. Test method: The contents of N, P2O5, K2O and trace elements in fertilizers were determined according to the NY / T 2542-2014 standard.

[0054] 2. The test results are shown in Table 1:

[0055] Table 1. Trace element content of different samples

[0056]

[0057] 3. Results Analysis: The N and K2O contents of Examples 1-3 were significantly higher than those of Comparative Example 3, and they were rich in trace elements such as Zn, Cu, and B, as well as amino acids. Comparative Example 1 did not use the mother liquor, and its amino acid content was 0, proving that the mother liquor is the main source of amino acids; Comparative Example 2 did not add trace elements, and its corresponding element content was 0, verifying the necessity of trace element additives.

[0058] II. Comparative Experiment on Maize Planting

[0059] 1. Experimental Design: The experimental site was selected in farmland in Jiyang District, Jinan City, Shandong Province. The soil type was brown soil, with a pH of 6.8 and an organic matter content of 1.8%. The maize variety "Zhengdan 958" was used. Six treatments were set up, including Examples 1-3 and Comparative Examples 1-3, with three replicates per treatment. The plots were randomized to 30 m². 2 The fertilizer application rate was 18 kg / mu (approximately 12.5 kg / acre) of total N-P2O5-K2O nutrients. Each group was set up with 3 replicates in a randomized block design. The experimental data were taken as average values, with an error range of ±2%.

[0060] 2. Measurement indicators: emergence rate, plant height, grain weight per plant, grain yield, and amino acid content in grains.

[0061] 3. The experimental results are shown in Table 2:

[0062] Table 2. Data on indicators measured using different corn planting samples.

[0063]

[0064] 4. Results Analysis: The emergence rate, plant height, yield, and grain amino acid content of Examples 1-3 were significantly higher than those of Comparative Example 3. Comparative Example 1, which did not use the mother liquor, experienced a yield decrease of approximately 15.3% and an amino acid content decrease of 31.4%, indicating that the amino acids in the mother liquor are crucial for improving crop quality. Comparative Example 2, lacking micronutrients, experienced a yield decrease of approximately 13.0%, demonstrating the promoting effect of micronutrients on crop growth.

[0065] III. Fertilizer Degradation Experiment

[0066] 1. Test method: The fertilizer granules were buried in farmland soil (moisture content 20%, temperature 25℃), and samples were taken after 30 days, 60 days and 90 days respectively. The residue rate was determined by gravimetric method.

[0067] 2. The test results are shown in Table 3:

[0068] Table 3. Fertilizer degradation residue data for different samples

[0069]

[0070]

[0071] 3. Results Analysis: The 90-day residue rates of Examples 1-3 were all below 10%, significantly lower than the 41.8% of Comparative Example 3, indicating that the fertilizer of the present invention has good biodegradability. Comparative Example 1, lacking the organic components of the mother liquor, had a slower degradation rate than the examples, verifying the role of organic matter in the mother liquor in improving the fertilizer's biodegradability.

[0072] IV. Economic Benefit Analysis

[0073] Taking Example 1 as an example, processing 1 ton of amino acid-type ammonium sulfate crystallization mother liquor can produce approximately 0.8 tons of agricultural fertilizer. The raw material cost includes a mother liquor treatment fee of 50 yuan, nitrogen-phosphorus-potassium compound fertilizer of 400 yuan, organic matter carrier of 120 yuan, and trace elements and functional additives of 80 yuan, totaling 650 yuan. Assuming a market price of 2000 yuan / ton, the net profit per ton of mother liquor treated is 0.8 × 2000 - 650 = 950 yuan. If a company processes 100,000 tons of mother liquor annually, the annual profit will increase by approximately 95 million yuan, while simultaneously reducing wastewater treatment costs by approximately 10 million yuan per year, demonstrating significant economic and environmental benefits.

[0074] In summary, through comparative experiments using examples and comparative examples, the method for preparing agricultural fertilizer from amino acid-type ammonium sulfate crystallization mother liquor provided by this invention has the following advantages:

[0075] 1. Realize the high-value utilization of industrial by-products, construct a closed-loop model of "wastewater-resource-fertilizer", and reduce environmental pollution.

[0076] 2. After optimization of process parameters, the fertilizer nutrients are balanced, with both fast and long-lasting effects, significantly improving crop yield and quality.

[0077] 3. The synergistic effect of microbial flora and bioactive adjuvants enhances the soil improvement capacity and biodegradability of fertilizers.

[0078] 4. Low production cost, suitable for large-scale industrial application, significant economic and social benefits, and promotes green and sustainable agricultural development.

[0079] The above embodiments are merely one of the preferred embodiments of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but solve the same technical problem as the present invention, should be included within the scope of protection of the present invention.

Claims

1. A method for preparing agricultural fertilizer from amino acid-type ammonium sulfate crystallization mother liquor, characterized in that, Includes the following steps: S1: The mother liquor of amino acid-type ammonium sulfate crystallization is concentrated by a single-effect or quadruple-effect concentrator, so that the volume of the mother liquor is reduced to 1 / 16 to 1 / 20 of the original volume. S2: The concentrated mother liquor is converted into a solid powder base material through a spray drying device; S3: Mix nitrogen, phosphorus and potassium compound fertilizer, organic matter carrier, trace element additives and functional additives evenly according to the weight ratio to form an auxiliary mixture; S4: Add the dried mother liquor base material and auxiliary material mixture into a twin-shaft mixer and mix thoroughly; S5: Granulation is carried out by a granulator and low-temperature drying in a blower drying equipment to obtain finished fertilizer.

2. The method for preparing agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to claim 1, characterized in that, The fertilizer is made from the following components in the following weight ratio: 500-600 parts of amino acid-type ammonium sulfate crystallization mother liquor, 200-300 parts of nitrogen-phosphorus-potassium compound fertilizer, 100-150 parts of organic matter carrier, 5-10 parts of trace element additives, and 3-8 parts of functional adjuvants; the nutrient ratio of the nitrogen-phosphorus-potassium compound fertilizer is N-P2O5-K2O=15-15-15 to 20-10-20; the organic matter carrier is one or more of humic acid and straw powder; the trace element additives are a mixture of zinc sulfate, copper sulfate, and boric acid; and the functional adjuvants are chitosan or sodium alginate.

3. The method for preparing agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to claim 2, characterized in that, The fertilizer is made from the following components in the following weight ratio: 550 parts of amino acid-type ammonium sulfate crystal mother liquor, 250 parts of nitrogen, phosphorus and potassium compound fertilizer, 120 parts of organic matter carrier, 7 parts of trace element additives and 5 parts of functional adjuvants.

4. The method for preparing agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to claim 1, characterized in that, The evaporation temperature of the concentration process is 60-80℃, and the vacuum degree is -0.08 to -0.09 MPa.

5. The method for preparing agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to claim 1, characterized in that, The inlet air temperature of the spray drying equipment is 180-200℃, the outlet air temperature is 80-90℃, and the spray disc rotation speed is 12000-15000 revolutions per minute.

6. The method for preparing agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to claim 1, characterized in that, The mixing time for the auxiliary material mixture is 15-20 minutes, and the rotation speed is 30-40 r / min.

7. The method for preparing agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to claim 1, characterized in that, The mixing time of the twin-shaft mixer is 25-30 minutes, and the rotation speed is 20 to 25 r / min.

8. The method for preparing agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to claim 1, characterized in that, The granulator in the granulation process has a rotation speed of 20-25 r / min and an inclination angle of 45-50 degrees.

9. The method for preparing agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to claim 1, characterized in that, The drying temperature of the blower drying equipment is 60-70℃, and the drying time is 30-40 minutes.

10. The method for preparing agricultural fertilizer from the mother liquor of amino acid-type ammonium sulfate crystallization according to claim 1, characterized in that, The finished fertilizer has a particle size of 2-4 mm.

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