CN116813400A - Method for producing multi-component full-water-soluble solid water-soluble fertilizer by co-crystallization method - Google Patents
Method for producing multi-component full-water-soluble solid water-soluble fertilizer by co-crystallization method Download PDFInfo
- Publication number
- CN116813400A CN116813400A CN202310691441.XA CN202310691441A CN116813400A CN 116813400 A CN116813400 A CN 116813400A CN 202310691441 A CN202310691441 A CN 202310691441A CN 116813400 A CN116813400 A CN 116813400A
- Authority
- CN
- China
- Prior art keywords
- water
- crystallization
- soluble fertilizer
- product
- soluble
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000003337 fertilizer Substances 0.000 title claims abstract description 80
- 238000000034 method Methods 0.000 title claims abstract description 52
- 239000007787 solid Substances 0.000 title claims abstract description 46
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 43
- 238000002288 cocrystallisation Methods 0.000 title claims abstract description 42
- 239000002994 raw material Substances 0.000 claims abstract description 59
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 29
- 235000015097 nutrients Nutrition 0.000 claims abstract description 21
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 10
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 6
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 5
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000011574 phosphorus Substances 0.000 claims abstract description 5
- 239000011591 potassium Substances 0.000 claims abstract description 5
- 150000003839 salts Chemical class 0.000 claims abstract description 4
- 239000013078 crystal Substances 0.000 claims description 65
- 239000000047 product Substances 0.000 claims description 60
- 238000001816 cooling Methods 0.000 claims description 44
- 238000002425 crystallisation Methods 0.000 claims description 43
- 230000008025 crystallization Effects 0.000 claims description 43
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 27
- 238000001914 filtration Methods 0.000 claims description 24
- 239000000706 filtrate Substances 0.000 claims description 23
- 238000007738 vacuum evaporation Methods 0.000 claims description 20
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 claims description 18
- 239000012452 mother liquor Substances 0.000 claims description 17
- 239000000203 mixture Substances 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 12
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 12
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 10
- 238000001471 micro-filtration Methods 0.000 claims description 10
- 239000002609 medium Substances 0.000 claims description 9
- 239000001103 potassium chloride Substances 0.000 claims description 9
- 235000011164 potassium chloride Nutrition 0.000 claims description 9
- 235000011118 potassium hydroxide Nutrition 0.000 claims description 9
- 239000005696 Diammonium phosphate Substances 0.000 claims description 8
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 claims description 8
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 claims description 8
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 claims description 8
- 229910000388 diammonium phosphate Inorganic materials 0.000 claims description 8
- 235000019838 diammonium phosphate Nutrition 0.000 claims description 8
- 239000006012 monoammonium phosphate Substances 0.000 claims description 8
- 235000019837 monoammonium phosphate Nutrition 0.000 claims description 8
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 6
- 239000004202 carbamide Substances 0.000 claims description 6
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 6
- 235000010333 potassium nitrate Nutrition 0.000 claims description 6
- 239000004323 potassium nitrate Substances 0.000 claims description 6
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 4
- 239000004115 Sodium Silicate Substances 0.000 claims description 2
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims description 2
- 229960003390 magnesium sulfate Drugs 0.000 claims description 2
- 235000019341 magnesium sulphate Nutrition 0.000 claims description 2
- 229940099596 manganese sulfate Drugs 0.000 claims description 2
- 239000011702 manganese sulphate Substances 0.000 claims description 2
- 235000007079 manganese sulphate Nutrition 0.000 claims description 2
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 claims description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 2
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 2
- 239000000725 suspension Substances 0.000 claims description 2
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 claims description 2
- 229960001763 zinc sulfate Drugs 0.000 claims description 2
- 229910000368 zinc sulfate Inorganic materials 0.000 claims description 2
- 235000016709 nutrition Nutrition 0.000 abstract description 13
- 239000004615 ingredient Substances 0.000 abstract description 9
- 239000002738 chelating agent Substances 0.000 abstract description 5
- 239000002270 dispersing agent Substances 0.000 abstract description 5
- 230000008901 benefit Effects 0.000 abstract description 4
- 239000006184 cosolvent Substances 0.000 abstract description 4
- 239000003795 chemical substances by application Substances 0.000 abstract description 3
- 230000005496 eutectics Effects 0.000 abstract description 2
- 238000003756 stirring Methods 0.000 description 20
- 238000005086 pumping Methods 0.000 description 15
- 239000002245 particle Substances 0.000 description 10
- 230000008569 process Effects 0.000 description 7
- 230000009467 reduction Effects 0.000 description 7
- 238000003860 storage Methods 0.000 description 7
- 238000004458 analytical method Methods 0.000 description 6
- 239000002826 coolant Substances 0.000 description 6
- 239000000498 cooling water Substances 0.000 description 6
- 238000004321 preservation Methods 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 238000000967 suction filtration Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 235000013877 carbamide Nutrition 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 230000035764 nutrition Effects 0.000 description 4
- 235000011181 potassium carbonates Nutrition 0.000 description 4
- 230000006837 decompression Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 239000012047 saturated solution Substances 0.000 description 3
- 239000001692 EU approved anti-caking agent Substances 0.000 description 2
- 239000002671 adjuvant Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 238000012432 intermediate storage Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000010413 mother solution Substances 0.000 description 2
- 230000006911 nucleation Effects 0.000 description 2
- 238000010899 nucleation Methods 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05B—PHOSPHATIC FERTILISERS
- C05B7/00—Fertilisers based essentially on alkali or ammonium orthophosphates
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Fertilizers (AREA)
Abstract
The invention discloses a method for producing a multi-component full water-soluble solid water-soluble fertilizer by using a co-crystallization method. Producing a multi-component full-water-soluble solid water-soluble fertilizer by using water-soluble fertilizer raw materials through a co-crystallization method; the water-soluble fertilizer raw material is a fertilizer grade or industrial grade raw material. The water-soluble fertilizer raw materials comprise nitrogen, phosphorus and potassium raw materials and medium and trace nutrient raw materials; the solid water-soluble fertilizer is a eutectic, simple solid adduct or double salt. The invention has the advantages that no cosolvent, dispersant and chelating agent are needed in production, and no anti-caking agent is needed in the product; the production process is green and environment-friendly; the nutritional ingredients of the product can be used for producing the multi-component solid water-soluble fertilizer with different nutritional ingredient proportions according to different crops and different nutritional ingredient requirements in different growth periods; the product has the characteristics of high purity and full water solubility, and is suitable for industrialized popularization.
Description
Technical Field
The invention relates to a method for producing solid water-soluble fertilizer, in particular to a method for producing multi-component full water-soluble solid water-soluble fertilizer by using a co-crystallization method.
Background
The water-soluble fertilizer is a multi-element compound quick-acting fertilizer which can be completely dissolved in water, and is characterized in that the water-soluble fertilizer can be fully dissolved in water and can be absorbed by rhizomes and leaves of plants to realize water-fertilizer integration. The multi-component soluble fertilizer can not only improve the utilization rate of water and nutrients, but also save labor force and improve the utilization rate of cultivated lands, can ensure the nutrition balance of crops, is beneficial to environmental protection and soil improvement, and improves the production and quality of agriculture. Along with the increasingly mature and popularization of industrial and soilless culture technologies, the requirements of the multi-component water-soluble fertilizer are also increasingly greater. The water-soluble fertilizer is divided into liquid and solid, and the liquid water-soluble fertilizer is inconvenient to store and transport, has high transportation cost and is limited in use. Solid water-soluble fertilizers become the main development trend of water-soluble fertilizers.
The existing solid water-soluble fertilizer is produced by adopting a physical and mechanical mixing method, and is usually prepared by physically mixing raw material fertilizer containing N, P, K and other nutrients through a mechanical device. Although the method has low cost, the fertilizer product has uneven nutrient distribution, more insoluble impurities, uneven product particle size, poor stability, easy caking and slow dissolution in use. To overcome these drawbacks, dispersants, chelating agents, dissolution aids and anti-caking agents are often added during production. The use of these adjuvants not only increases the cost, but also has many adverse effects on the soil and the environment, and these adjuvants can remain in the crop product.
Aiming at the technical problems, the invention provides a method for producing a multi-component full water-soluble solid water-soluble fertilizer by using a co-crystallization method.
Disclosure of Invention
The invention aims to provide a method for producing a multi-component full water-soluble solid water-soluble fertilizer by using a co-crystallization method. The invention has the advantages that no cosolvent, dispersant and chelating agent are needed in production, and no anti-caking agent is needed in the product; the production process is green and environment-friendly; the nutritional ingredients of the product can be used for producing the multi-component solid water-soluble fertilizer with different nutritional ingredient proportions according to different crops and different nutritional ingredient requirements in different growth periods; the product has the characteristics of high purity and full water solubility, and is suitable for industrialized popularization.
The technical scheme of the invention is as follows: a method for producing multi-component full water-soluble solid water-soluble fertilizer by using a co-crystallization method uses water-soluble fertilizer raw materials to produce the multi-component full water-soluble solid water-soluble fertilizer by using the co-crystallization method.
In the method for producing the multi-component full-water-soluble solid water-soluble fertilizer by using the co-crystallization method, the water-soluble fertilizer raw material is a fertilizer grade or industrial grade raw material. The water-soluble fertilizer raw materials comprise raw materials of nitrogen, phosphorus, potassium and medium and trace nutrient elements; the solid water-soluble fertilizer is one or a mixture of a plurality of co-crystals, simple solid adducts and double salts.
In the method for producing the multi-component full-water-soluble solid water-soluble fertilizer by using the co-crystallization method, the nitrogen raw material is urea, monoammonium phosphate or/and diammonium phosphate; the phosphorus raw material is monoammonium phosphate or/and diammonium phosphate; the potassium raw material is potassium chloride, potassium nitrate, potassium hydroxide or/and potassium carbonate; the medium and trace nutrient elements are zinc sulfate, magnesium sulfate, manganese sulfate or/and sodium silicate.
In the method for producing the multi-component full water-soluble solid water-soluble fertilizer by using the co-crystallization method, the co-crystallization method adopts cooling crystallization or vacuum evaporation crystallization.
The method for producing the multi-component full water-soluble solid water-soluble fertilizer by using the co-crystallization method comprises the following steps of:
(1) Adding water and part of circulating mother liquor into the water-soluble fertilizer raw material, heating and dissolving to obtain a product A;
(2) Filtering the A product and carrying out microfiltration to obtain a B product;
(3) Adding the rest part of concentrated circulating mother liquor into the product B, adopting cooling crystallization or vacuum evaporation crystallization, adding seed crystal, and continuing crystallization operation until crystallization is finished to obtain suspension as product C;
(4) Filtering the product C to obtain a crystal product D, wherein the filtrate is a mother liquor product E; directly returning the E product part to the step (1) for use, and returning the E product of the rest part to the step (3) for use after concentrating;
(5) And (5) drying the D product to obtain a finished product.
In the method for producing the multi-component full-water-soluble solid water-soluble fertilizer by using the co-crystallization method, in the step (1), the heating and dissolving temperature is 50-95 ℃; in the step (2), the temperature of filtration and microfiltration is 50-95 ℃, and when the water-soluble fertilizer raw material is industrial grade, no filtration is carried out.
In the method for producing the multi-component full water-soluble solid water-soluble fertilizer by the co-crystallization method, in the step (3), when the continuous operation is carried out, only when the solution temperature is lower than the saturation temperature by 0.5-5 ℃, seed crystals which have the same proportion as the raw materials and are 0.1-5% of the mass of the raw materials are added, and after steady-state production, the seed crystals are not needed to be added; the grain size of the seed crystal is 200-500 mu m.
In the aforementioned method for producing a multi-component fully water-soluble solid water-soluble fertilizer by using a co-crystallization method, in the step (3), the cooling crystallization specifically comprises the following steps: program cooling, wherein the cooling rate is 0.5-5 ℃/h, and the crystallization final temperature is 15-50 ℃; growing the crystals for 0-3h at the crystallization finish degree; the cooling crystallization adopts intermittent or continuous operation, and three-stage crystallization operation is adopted during continuous operation; the crystallizer used is a general purpose OSLO, DTB cooled crystallizer.
In the aforementioned method for producing a multi-component fully water-soluble solid water-soluble fertilizer by using a co-crystallization method, in the step (3), the vacuum evaporation crystallization specifically comprises the following steps: program control pressure and cooling, vacuum degree is 53000pa-7000pa absolute pressure, cooling rate is 0.5-5 ℃/h, crystallization final temperature is 15-50 ℃; growing the crystal for 0-3h at the crystallization finishing temperature; the vacuum evaporation crystallization adopts intermittent or continuous operation, and three-stage crystallization operation is adopted in the continuous operation; the crystallizer used is a conventional OSLO or DTB vacuum evaporation crystallizer.
In the method for producing the multi-component full water-soluble solid water-soluble fertilizer by the co-crystallization method, in the step (4), 0-20wt% of E product is directly returned to the step (1) for use, and 80-100deg.C of E product in the rest is concentrated and returned to the step (3) for use;
in the step 5, a tunnel dryer or a fluidized bed dryer is adopted;
the steps (1) - (5) are operated in batch or continuous mode.
Compared with the prior art, the invention has the following beneficial effects:
the co-crystallization method of the present invention refers to a method in which multiple components precipitate solid materials from vapor, solution or melt in the form of eutectic or simple adducts or double salts. It is distinguished from conventional single component crystallization. The process not only can effectively solve the problems of poor dispersibility and poor uniformity of the compound, but also can improve the crystal form, fluidity, hygroscopicity and stability of the product. The melting point, the solubility, the stability and the bioavailability of the material are improved on the premise of not affecting the physical and chemical properties of the material. By changing the proportion of different components of the raw materials, the solid water-soluble fertilizer with multiple nutrient elements in different plant nutrient component proportions can be produced, and the requirements of different crops and different growth periods on the nutrient elements are met. Co-crystallization technology, which was developed in the last century as one of industrial crystallization technologies, has been gaining attention because of the advantage of green environmental protection without using auxiliary agents. The multi-component full water-soluble fertilizer is produced by using a co-crystallization method, so that the addition of various dispersing agents, cosolvent, chelating agents and anti-caking agents can be effectively avoided.
Experiments prove that:
the technical scheme of the invention comprises four typical process flows:
1. schematic flow chart of batch cooling co-crystallization, see fig. 1, comprising the following steps:
(1) 2-3 of fertilizer grade or industrial grade urea, potassium chloride, potassium nitrate, potassium hydroxide, potassium carbonate, monoammonium phosphate, diammonium phosphate and the like serving as raw materials of main nutrients are dissolved in proper water and partial mother liquor at 50-95 ℃ according to the proportion in a batching tank with stirring and heating;
(2) If necessary, adding appropriate amount of medium or trace nutrient raw materials;
(3) Filtering and micro-filtering while the materials are hot, wherein the filters and the micro-filters need to be kept warm;
(4) Placing the filtrate in a crystallizer with stirring and cooling; setting a program cooling rate of 0.5-5 ℃/h;
(5) Adding 0.1-5% of the mass of the raw materials at the temperature lower than the saturation temperature by 0.5-5%, proportioning the raw materials as the main nutrient raw materials, and grinding the raw materials to seed crystals with the particle size of 200-500 mu m;
(6) Continuing program cooling to 15-50 ℃ of crystallization finishing temperature; growing the crystal for 0-3h at the crystallization finishing temperature;
(7) Filtering;
(8) Drying the obtained crystal to obtain a product;
(9) And (3) concentrating one part of the filtrate to an appropriate concentration, returning to the step (4), and returning the other part of the filtrate to the dosing tank.
2. A schematic flow chart of continuous cooling co-crystallization comprises the following steps, and is shown in fig. 2.
(1) In a batching tank with stirring and heating, 2-3 of raw materials of main nutrients, fertilizer grade or industrial grade urea, potassium chloride, potassium nitrate, potassium hydroxide, potassium carbonate, monoammonium phosphate and diammonium phosphate are dissolved in proper water and circulating mother liquor at 50-95 ℃ according to the proportion;
(2) If necessary, adding appropriate amount of medium or trace nutrient raw materials;
(3) Filtering while the mixture is hot, and then carrying out microfiltration; the filter and the micro-filter need to be insulated; the filtrate is sent into a buffer tank with heating;
(4) Pumping the first stage crystallizer continuously from the buffer tank at a set flow rate by a pump, wherein the temperature of the stage cooling water is set to be 40-60 ℃; pumping the mixture into a second stage crystallizer continuously according to a set flow rate by a pump, wherein the temperature of cooling water of the second stage is set to be 35-50 ℃ at the final temperature of crystallization; pumping the mixed solution into a third-stage crystallizer continuously according to a set flow rate by a pump, wherein the temperature of cooling water of the third-stage crystallizer is set to be 15-40 ℃ at the final crystallization temperature, and the third-stage crystallizer is a crystal growing crystallizer; only when the first stage crystallizer is started, adding seed crystals with the mass of 0.1-5% of the raw materials when the temperature of the solution is lower than the saturation temperature by 0.5-5 ℃ so as to avoid burst nucleation; after steady-state production, seed crystals are not needed to be added;
(5) Continuously feeding the solid-liquid mixture into a continuous filter by using a pump or by using the position height difference of equipment, and continuously filtering;
(6) Drying the obtained crystal to obtain a product;
(7) Part of the filtrate is concentrated to proper concentration and returned to the buffer tank, and the other part of the filtrate is directly returned to the proportioning tank.
3. A schematic flow chart of batch vacuum evaporation co-crystallization, see fig. 3, comprises the following steps:
(1) 2-3 of fertilizer grade or industrial grade urea, potassium chloride, potassium nitrate, potassium hydroxide, potassium carbonate, monoammonium phosphate and diammonium phosphate which are raw materials of main nutrients are dissolved in proper water at 50-95 ℃ according to the proportion in a batching tank with stirring and heating;
(2) If necessary, adding appropriate amount of medium or trace nutrient raw materials;
(3) Filtering while the mixture is hot, and then carrying out microfiltration; the filter and the micro-filter need to be insulated;
(4) Placing the filtrate in a vacuum evaporation crystallizer with stirring and cooling functions; setting a program cooling rate of 0.5-5 ℃/h;
(5) Adding 0.5-5% of the mass of the raw materials at the temperature lower than the saturation temperature by 0.5-5%, proportioning the raw materials as the main nutrient raw materials, and grinding the raw materials to seed crystals with the particle size of 200-500 mu m;
(6) Starting a vacuum pump, setting a program for vacuum adjustment, wherein the vacuum degree range is 53000pa (absolute pressure) -7000pa (absolute pressure); the vacuum adjustment is carried out through a variable frequency motor of the vacuum pump; growing the crystal for 0-3h at the crystallization finishing temperature of 15-30 ℃ and the vacuum degree of 9000pa (absolute pressure) -7000pa (absolute pressure);
(7) After the crystal growing is finished, opening and emptying, and stopping vacuumizing;
(8) Filtering, and drying the obtained crystal to obtain a product;
(9) And (3) concentrating part of filtrate to proper concentration, returning to the step (4), and directly returning the other part of mother liquor to the batching tank.
4. A schematic flow chart of continuous vacuum evaporation co-crystallization, see fig. 4, comprises the following steps:
(1) In a batching tank with stirring and heating, 2-3 of raw materials of main nutrients, fertilizer grade or industrial grade urea, potassium chloride, potassium nitrate, potassium hydroxide, potassium carbonate, monoammonium phosphate and diammonium phosphate are dissolved in a proper amount at 50-95 ℃ according to the proportion;
(2) If necessary, adding appropriate amount of medium or trace nutrient raw materials;
(3) Filtering while the mixture is hot, and then carrying out microfiltration; the filter and the micro-filter need to be insulated; the filtrate is sent into a buffer tank with heating;
(4) Continuously pumping the first-stage crystallizer from a buffer tank according to a set flow rate by a pump, wherein the temperature of the cooling water of the first-stage crystallizer is set to be 40-60 ℃ and the vacuum degree is 53000pa (absolute pressure) -43000pa (absolute pressure); continuously pumping the mixture into a second stage crystallizer according to a set flow rate by a pump, wherein the temperature of cooling water of the second stage is set to be 35-50 ℃ at the final crystallization temperature, and the vacuum degree is 43000pa (absolute pressure) -9000pa (absolute pressure); continuously pumping the mixture into a third-stage crystallizer according to a set flow rate by a pump, wherein the temperature of cooling water of the third-stage crystallizer is set to be 15-40 ℃ at the final crystallization temperature and the vacuum degree is 9000pa (absolute pressure) -7000pa (absolute pressure); the stage crystallizer is a crystal growing crystallizer. Only when the first stage crystallizer is started, adding seed crystals with the mass of 0.1-5% of the raw materials when the temperature of the solution is lower than the saturation temperature by 0.5-5 ℃ so as to avoid burst nucleation; after the seed is added, the vacuum pump is turned on. After steady-state production, seed crystals are not needed to be added;
(5) Continuously feeding the solid-liquid mixture into a continuous filter by using a pump or by using the position height difference of equipment, and continuously filtering;
(6) Drying the obtained crystal to obtain a product;
(7) Part of the filtrate is concentrated to proper concentration and returned to the buffer tank, and the other part of the mother liquor is directly returned to the proportioning tank.
Specific statement: during intermittent operation, any increase and decrease program cooling or vacuum degree progression is within the protection scope of the patent.
Specific statement: during continuous operation, seed crystals are only needed to be added at proper time when the equipment is started, so that seed crystals are not needed to be added after stable production; the pump flow rate is determined after calculation according to the capacity; the size of the crystallizer is determined by calculation according to the residence time of the material in the crystallizer. Any increase or decrease in the number of crystallization stages, as well as changes in the operating temperature and vacuum of the crystallizer, are within the scope of the present patent claims.
Specific statement: by adopting the method, only by changing the raw material proportion and adding other medium and trace elements, a certain special fertilizer is added, and the method is within the protection scope of the patent.
In summary, the invention has the advantages that no cosolvent, dispersant and chelating agent are needed in production, and no anti-caking agent is needed in the product; the production process is green and environment-friendly; the nutritional ingredients of the product can be used for producing the multi-component solid water-soluble fertilizer with different nutritional ingredient proportions according to different crops and different nutritional ingredient requirements in different growth periods; the product has the characteristics of high purity and full water solubility, and is suitable for industrialized popularization.
Drawings
FIG. 1 is a schematic flow diagram of a batch cooling co-crystallization process according to the present invention;
FIG. 2 is a schematic flow chart of the continuous cooling co-crystallization of the present invention;
FIG. 3 is a schematic flow chart of batch vacuum evaporation co-crystallization according to the present invention;
FIG. 4 is a schematic flow chart of the continuous vacuum evaporation co-crystallization of the invention.
Detailed Description
The invention is further illustrated in the following examples with reference to figures 1-4, which are not intended to be limiting.
Example 1:
at 95℃technical grade 32gNH 4 H 2 PO 4 And 68g (NH) 2 ) 2 CO, dissolved in 80g of water. Microfiltration is carried out while the filtrate is hot at 95 ℃, and the filtrate is placed in a crystallizer with a cooling jacket. Stirring is started, and the stirring speed is fixed at 300r/min. Program cooling: the temperature reduction rate is 0.5 ℃/h in the range of 95-80 ℃; the temperature reduction rate is 5 ℃/h in the range of 80-50 ℃. At 94℃NH was added 4 H 2 PO 4 /(NH 2 ) 2 The mass ratio of CO is 1:1, and the seed crystal with the particle size of 500 μm is 1g. Stopping cooling when the temperature is reduced to 50 ℃, and growing the crystal for 1h. After suction filtration and drying, 55.5g of crystal product is obtained. After analysis, the product is N29.94% and P 2 O 5 27.38% of water insoluble matter 0.01%.
Example 2:
at 80℃technical grade 23.8g KCl, 27.5g (NH) 2 ) 2 CO and 10g MnSO 4 Dissolved in 52.9g of water. Microfiltration was carried out at 80℃while hot, and the filtrate was placed in a cooling jacketed crystallizer. Stirring is started, and the stirring speed is fixed at 250r/min. Program cooling: the temperature reduction rate is 1 ℃/h in the range of 80-50 ℃; the temperature reduction rate is 4 ℃/h in the range of 50-30 ℃. At 78 ℃, KCl/(NH) is added 2 ) 2 The mass ratio of CO is 1:1, and the seed crystal with the particle size of 200 mu m is 0.5g. Stopping cooling when the temperature is reduced to 30 ℃, and growing the crystal for 0.5h. After suction filtration and drying, 35.91g of a crystal product was obtained. After analysis, the product is 40.99% N and K 2 O20.05%, mn2.11% and S1.22%. No water insoluble matter.
Example 3:
at 50 ℃, willTechnical grade 76.2gNH 4 H 2 PO 4 、32.8g(NH 2 ) 2 CO and ZnSO 4 10g, dissolved in 150g of water. Microfiltration was carried out at 50℃while hot, and the filtrate was placed in a crystallizer with a cooling jacket and connected to a vacuum pump. The magnetic stirring is started, and the stirring speed is fixed at 400r/min. Program cooling: the temperature reduction rate is 0.5 ℃/h in the range of 50-45 ℃; the cooling rate is 3 ℃/h in the temperature range of 45-15 ℃. At 48.5℃NH was added 4 H 2 PO 4 /(NH 2 ) 2 The mass ratio of CO is 1:1, and the seed crystal with the particle size of 400 μm is 1g. Then vacuumizing, wherein the vacuum degree is 43000pa (absolute pressure) in the temperature range of 50-45 ℃; vacuum 9000pa (absolute pressure) at 45-15deg.C. Stopping cooling when the temperature is reduced to 45 ℃, and growing the crystal for 3 hours. After suction filtration and drying, 42.6g of a crystal product was obtained. After analysis, the product was 28.76% N and P 2 O 5 47.38%, containing Zn2.46% and S1.41%. 0.01% of water insoluble matter.
Example 4:
fertilizer grade 62gNH at 75 ℃ 4 H 2 PO 4 、42gK 2 CO 3 And 14.4MgSO 4 Dissolved in 110g of water. Filtering and micro-filtering the hot solution at 75 ℃, and placing the filtrate into a crystallizer with a cooling jacket. Stirring is started, and the stirring speed is fixed at 500r/min. Program cooling: the cooling rate is 1 ℃/h in the temperature range of 75-65 ℃; the cooling rate is 5 ℃/h in the temperature range of 65-25 ℃. At 72℃add (NH) 4 ) 2 HPO 4 And K 2 The mass ratio of CO is 1:1, and the seed crystal with the particle size of 100 μm is 1.5g. Stopping cooling when the temperature is reduced to 25 ℃, and growing the crystal for 2 hours. After suction filtration and drying, 55.5g of crystal product is obtained. After analysis, the product was 22.84% N and P 2 O 5 20.35%, K-containing 2 20.25% of O, 1.51% of Mgand 1.01% of S. 0.05% of water insoluble matter.
Example 5:
at 65℃the fertilizer grade 60g (NH 4 ) 2 HPO 4 40g KOH and 20g15% NaSiO 3 The solution was dissolved in 150g of water. At 65℃the filtrate was filtered while hot, microfiltered, jacketed with a cooling jacket and connected to a vacuum pump crystallizer, and 32g of the concentrated crystallization mother liquor of example 2 was added. Opening the valveMagnetic stirring is carried out, and the fixed stirring speed is 400r/min. Program cooling: the cooling rate is 0.5 ℃/h in the temperature range of 65-55 ℃; the temperature reduction rate is 2 ℃/h in the range of 55-25 ℃. At 62.5℃add (NH) 4 ) 2 HPO 4 The mass ratio of KOH/seed crystal is 1:1, and the seed crystal with the particle size of 200 mu m is 5g. Then vacuumizing, wherein the vacuum degree is 33000pa (absolute pressure) at the temperature of 65-55 ℃; vacuum degree 7000pa (absolute pressure) in the range of 55-25 ℃. Stopping cooling when the temperature is reduced to 25 ℃, and growing the crystal for 0h. After suction filtration and drying, 65.5g of crystal product is obtained. After analysis, the product was 26.75% N and P 2 O 5 18.35%, K-containing 2 24.15% of O and 1.31% of Si. 0.08% of water insoluble matter.
Example 6:
fertilizer grade 42gNH at 85 DEG C 4 H 2 PO 4 And 78g (NH) 2 ) 2 CO，38gKNO 3 Dissolved in 140g of water and 30g of the filtrate from example 1. Filtering and micro-filtering at 85deg.C, and placing the filtrate in a crystallizer with cooling jacket. Stirring is started, and the stirring speed is fixed at 200r/min. Program cooling: the temperature reduction rate is 2 ℃/h in the range of 85-75 ℃; the cooling rate is 5 ℃/h in the temperature range of 75-35 ℃. At 82℃NH was added 4 H 2 PO 4 /(NH 2 ) 2 The mass ratio of CO is 1:1, and the seed crystal with the particle size of 250 μm is 5g. Stopping cooling when the temperature is reduced to 35 ℃, and growing crystals 0.h. After suction filtration and drying, 55.5g of crystal product is obtained. After analysis, the product was found to contain 32.65% N and P 2 O 5 20.15%, K-containing 2 O19.15%. 0.05% of water insoluble matter.
Example 7:
fertilizer grade (NH) 2 ) 2 CO、K 2 CO 3 、NH 4 H 2 PO 4 And ZnSO 4 The saturated solution is prepared according to the proportion of 55%,20% and 5% (mass ratio) at 70 ℃ and is placed in a raw material storage tank with stirring and heat preservation. At a certain flow rate, e.g. 6m, by a pump 3 And (h) pumping the mixture into a filter, a micro-filter and placing the filtrate in a middle storage tank with heat preservation. From the tank by a pump at a flow rate of, for example, 6m 3 Continuously feeding into first-stage vacuum evaporation crystallizer, feeding at 70 deg.C and 6 deg.CAt 5 deg.c (during running and 68 deg.c), seed crystal of 300 microns size in 1kg is added, the seed crystal is mixed with the material and the mixture is pumped to vacuum, and the seed crystal is not required to be added after stable production and the operation pressure is about 23000 Pa. With a pump at 6m 3 And pumping into a second-stage vacuum evaporation crystallizer, wherein the feeding temperature of the second-stage vacuum evaporation crystallizer is 65 ℃, the operating temperature of the crystallizer is 55 ℃, and the operating pressure is about 13000pa (absolute). With a pump at 6m 3 And pumping the flow rate/h into a third-stage vacuum evaporation crystallizer, wherein the feeding temperature of the third-stage vacuum evaporation crystallizer is 55 ℃, the operating temperature of the crystallizer is 45 ℃, and the operating pressure is about 7000pa (absolute). With a pump at 6m 3 And/h, pumping into a continuous filter. And (5) filtering. And (3) feeding 60% of filtered mother liquor into a decompression MVR evaporation concentration system, concentrating, returning to the intermediate storage tank, and returning 40% of mother liquor to the proportioning tank. And (5) the filtered crystals enter a continuous dryer and are dried to obtain the product. The yield was 3t/h, the once-through yield was 36.24%, and the whole process yield (mother liquor recycle) was 94.21%. The product contains N35.21%, P 2 O 5 18.15％，K 2 O25.65%, zn2.1% and S2.01%. The water insolubles were 0.08%.
The solid full-water soluble fertilizer with different yields and different nutrition component proportions can be obtained by changing the proportion of raw materials and the operating conditions of each stage of crystallizer, and different yields can be obtained by changing the flow.
Example 8:
fertilizer grade (NH) 2 ) 2 CO, KCl and (NH) 4 ) 2 HPO 4 The saturated solution is prepared according to the proportion of 40 percent, 20 percent and 40 percent (mass ratio) at 65 ℃ and is placed in a raw material storage tank with stirring and heat preservation. At a certain flow rate, e.g. 4m, by a pump 3 And (h) pumping the mixture into a filter, a micro-filter and placing the filtrate in a middle storage tank with heat preservation. From the tank, 4m by pump 3 And (3) continuously pumping the mixture into a first-stage cooling crystallizer at the flow rate of/h, wherein the feeding temperature is 65 ℃ (when the vehicle is started, 1kg of seed crystal with the grain diameter of 400 mu m is added at the temperature of 60 ℃, the seed crystal with the raw material ratio is proportioned, then vacuumizing is carried out, the seed crystal is not needed after stable production), and the coolant inlet temperature is 50 ℃. With a pump at 4m 3 Flow rate/h, pump into second stage cooling crystallizer, feed temperature of second stage cooling crystallizer 48 ℃, coolant inlet temperature of 30 ℃. By pumpsAt 4m 3 The flow rate/h was pumped into a third stage cooling crystallizer at a feed temperature of 26℃and a coolant inlet temperature of 25 ℃. With a pump at 4m 3 And/h, pumping into a continuous filter. And (5) filtering. 80% of the filtered mother solution enters a decompression MVR evaporation concentration system, and returns to the middle storage tank after being concentrated. The 20% mother liquor is returned to the batching tank. And (5) the filtered crystals enter a continuous dryer and are dried to obtain the product. The yield was 2t/h, the single pass yield was 44.79%, and the whole process yield (mother liquor recycle) was 95.67%. The product contains N35.21%, P 2 O 5 20.15%, K-containing 2 O21.25%. The water insoluble content was 0.07%.
The solid full-water soluble fertilizer with different yields and different nutrition component proportions can be obtained by changing the proportion of raw materials and the operation conditions of each stage of crystallizer: varying the flow rate can result in different yields.
Example 9:
industrial grade (NH) 2 ) 2 CO, KOH and NH 4 H 2 PO 4 The saturated solution is prepared according to the proportion of 40 percent, 20 percent and 60 percent (mass ratio) at the temperature of 85 ℃ and is placed in a raw material storage tank with stirring and heat preservation. At a certain flow rate, e.g. 5m, by a pump 3 And (h) pumping the mixture into a micro-filter, and placing the filtrate in a middle storage tank with heat preservation. From the tank, 5m by a pump 3 And (3) continuously pumping the mixture into a first-stage cooling crystallizer at the flow rate of/h, wherein the feeding temperature is 85 ℃ (at 84.5 ℃ in the starting process), 5kg of seed crystals with the particle size of 300 mu m are added, the seed crystals with the same raw material proportion are proportioned, then vacuumizing is carried out, the seed crystals are not needed after stable production), and the coolant inlet temperature is 60 ℃. With a pump at 5m 3 The flow rate/h was pumped into a second stage cooling crystallizer with a feed temperature of 65℃and a coolant inlet temperature of 50 ℃. With a pump at 5m 3 The flow rate/h was pumped into a third stage cooling crystallizer at a feed temperature of 55℃and a coolant inlet temperature of 35 ℃. Using the height difference of the equipment to be 5m 3 And/h, feeding into a continuous filter. And (5) filtering. 100% of the filtered mother solution enters a decompression MVR evaporation concentration system, and returns to the intermediate storage tank after being concentrated. And (5) the filtered crystals enter a continuous dryer and are dried to obtain the product. The yield was 2.5t/h, the once-through yield was 51.23%, and the whole process yield (mother liquor circulation) was 98.10%. The product contains N32.41%, P 2 O 5 30.35%, containing K 2 O31.28%. The water insoluble content was 0.04%.
The solid full-water soluble fertilizer with different yields and different nutrition component proportions can be obtained by changing the proportion of raw materials and the operation conditions of each stage of crystallizer: varying the flow rate can result in different yields.
Claims (10)
1. A method for producing multi-component full water-soluble solid water-soluble fertilizer by using a co-crystallization method is characterized in that: the water-soluble fertilizer raw material is used for producing the multi-component full water-soluble solid water-soluble fertilizer by a co-crystallization method.
2. The method for producing a multi-component fully water-soluble solid water-soluble fertilizer by a co-crystallization method according to claim 1, wherein the method comprises the following steps: the water-soluble fertilizer raw material is a fertilizer grade or industrial grade raw material. The water-soluble fertilizer raw materials comprise raw materials of nitrogen, phosphorus, potassium and medium and trace nutrient elements; the solid water-soluble fertilizer is one or a mixture of a plurality of co-crystals, simple solid adducts and double salts.
3. The method for producing a multi-component fully water-soluble solid water-soluble fertilizer by a co-crystallization method according to claim 2, wherein: the nitrogen raw material is urea, monoammonium phosphate or/and diammonium phosphate; the phosphorus raw material is monoammonium phosphate or/and diammonium phosphate; the potassium raw material is potassium chloride, potassium nitrate, potassium hydroxide or/and potassium carbonate; the medium and trace nutrient elements are zinc sulfate, magnesium sulfate, manganese sulfate or/and sodium silicate.
4. The method for producing a multi-component fully water-soluble solid water-soluble fertilizer by a co-crystallization method according to claim 2, wherein: the co-crystallization method adopts cooling crystallization or vacuum evaporation crystallization.
5. The method for producing a multi-component fully water-soluble solid water-soluble fertilizer by a co-crystallization method according to any one of claims 1 to 4, wherein: the method comprises the following steps:
(1) Adding water and part of circulating mother liquor into the water-soluble fertilizer raw material, heating and dissolving to obtain a product A;
(2) Filtering the A product and carrying out microfiltration to obtain a B product;
(3) Adding the rest part of concentrated circulating mother liquor into the product B, adopting cooling crystallization or vacuum evaporation crystallization, adding seed crystal, and continuing crystallization operation until crystallization is finished to obtain suspension as product C;
(4) Filtering the product C to obtain a crystal product D, wherein the filtrate is a mother liquor product E; directly returning the E product part to the step (1) for use, and returning the E product of the rest part to the step (3) for use after concentrating;
(5) And (5) drying the D product to obtain a finished product.
6. The method for producing a multi-component fully water-soluble solid water-soluble fertilizer by a co-crystallization method according to claim 5, wherein the method comprises the following steps: in the step (1), the temperature of heating and dissolving is 50-95 ℃; in the step (2), the temperature of filtration and microfiltration is 50-95 ℃, and when the water-soluble fertilizer raw material is industrial grade, no filtration is carried out.
7. The method for producing a multi-component fully water-soluble solid water-soluble fertilizer by a co-crystallization method according to claim 5, wherein the method comprises the following steps: in the step (3), during continuous operation, only when the solution temperature is lower than the saturation temperature by 0.5-5 ℃ during starting, seed crystals which have the same proportion as the raw materials and are 0.1-5% of the mass of the raw materials are added, and after steady-state production, the seed crystals are not needed to be added; the grain size of the seed crystal is 200-500 mu m.
8. The method for producing a multi-component fully water-soluble solid water-soluble fertilizer by a co-crystallization method according to claim 5, wherein the method comprises the following steps: in the step (3), the cooling crystallization specifically comprises the following steps: program cooling, wherein the cooling rate is 0.5-5 ℃/h, and the crystallization final temperature is 15-50 ℃; growing the crystal for 0-3h at the crystallization finishing temperature; the cooling crystallization adopts intermittent or continuous operation, and three-stage crystallization operation is adopted during continuous operation; the crystallizer used is a general purpose OSLO, DTB cooled crystallizer.
9. The method for producing a multi-component fully water-soluble solid water-soluble fertilizer by a co-crystallization method according to claim 5, wherein the method comprises the following steps: in the step (3), the vacuum evaporation crystallization specifically comprises the following steps: program control pressure and cooling, vacuum degree is 53000pa-7000pa absolute pressure, cooling rate is 0.5-5 ℃/h, crystallization final temperature is 15-50 ℃; growing the crystal for 0-3h at the crystallization finishing temperature; the vacuum evaporation crystallization adopts intermittent or continuous operation, and three-stage crystallization operation is adopted in the continuous operation; the crystallizer used is a conventional OSLO or DTB vacuum evaporation crystallizer.
10. The method for producing a multi-component fully water-soluble solid water-soluble fertilizer by a co-crystallization method according to claim 5, wherein the method comprises the following steps: in the step (4), 0-20wt% of E product is directly returned to the step (1) for use, and the rest 80-100deg.wt% of E product is returned to the step (3) for use after being concentrated;
in the step 5, a tunnel dryer or a fluidized bed dryer is adopted;
the steps (1) - (5) are operated in batch or continuous mode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310691441.XA CN116813400A (en) | 2023-06-13 | 2023-06-13 | Method for producing multi-component full-water-soluble solid water-soluble fertilizer by co-crystallization method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310691441.XA CN116813400A (en) | 2023-06-13 | 2023-06-13 | Method for producing multi-component full-water-soluble solid water-soluble fertilizer by co-crystallization method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116813400A true CN116813400A (en) | 2023-09-29 |
Family
ID=88123350
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310691441.XA Pending CN116813400A (en) | 2023-06-13 | 2023-06-13 | Method for producing multi-component full-water-soluble solid water-soluble fertilizer by co-crystallization method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116813400A (en) |
-
2023
- 2023-06-13 CN CN202310691441.XA patent/CN116813400A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101318914B (en) | Method for preparing urea phosphoric acid with wet-process phosphoric acid | |
| CN105646036A (en) | Method for producing multi-element water-soluble fertilizer | |
| CN112552167B (en) | Preparation method of calcium gluconate | |
| CN116813400A (en) | Method for producing multi-component full-water-soluble solid water-soluble fertilizer by co-crystallization method | |
| CN104876815A (en) | Sodium diformate preparation method | |
| CN115594545A (en) | Method for producing Gly-containing water-soluble fertilizer | |
| CN110590467B (en) | Balanced type suspension liquid fertilizer and preparation method thereof | |
| CN103771455B (en) | A kind of phosphogypsum sulphur ammonium increases the method for sulphur ammonium granularity | |
| JPS6351970B2 (en) | ||
| CN104261377B (en) | A kind of production method preparing potassium primary phosphate by-product shepherd's purse special fertilizer | |
| CN105237049A (en) | Production process of potassium sulfate specially used for drop irrigation | |
| CN105272601B (en) | A kind of water soluble fertilizer and preparation method thereof promoting Fruit containing moderate-element | |
| CN104291287B (en) | A kind of production method preparing ammonium dihydrogen phosphate by-product wax gourd special fertilizer | |
| JPH0764668B2 (en) | Liquid fertilizer manufacturing method | |
| CN104310343B (en) | A kind of production method preparing ammonium dihydrogen phosphate by-product Fructus Pruni pseudocerasi special fertilizer | |
| CN102515923B (en) | Drip irrigation-grade ammonium phosphate sulfate composite fertilizer and preparation process thereof | |
| CN107304138A (en) | Special water soluble fertilizer of a kind of watermelon and preparation method thereof | |
| CN115849318A (en) | Production process of full-water-soluble powdery potassium dihydrogen phosphate | |
| CN104291304A (en) | Production method for preparing calcium hydrogen phosphate and by-producing special fertilizer for cucurbit | |
| CN104291301B (en) | A kind of production method preparing dikalium phosphate by-product osmanthus fragrans special fertilizer | |
| CN102531709A (en) | Method for industrially and continuously producing crystalline urea | |
| CN104310329A (en) | Method for preparing ammonium dihydrogen phosphate and preparing special fertilizer for persimmons as byproduct | |
| CN104386660A (en) | Production method for special watermelon fertilizer as ammonium dihydrogen phosphate preparation byproduct | |
| CN104261378A (en) | Production method for preparing monopotassium phosphate and byproduct special fertilizer for medlar | |
| CN108863500A (en) | A kind of dedicated water soluble fertilizer of cucumber and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |