CN114478143A - Natural latex coated controlled-release fertilizer and preparation method thereof - Google Patents
Natural latex coated controlled-release fertilizer and preparation method thereof Download PDFInfo
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- CN114478143A CN114478143A CN202210216437.3A CN202210216437A CN114478143A CN 114478143 A CN114478143 A CN 114478143A CN 202210216437 A CN202210216437 A CN 202210216437A CN 114478143 A CN114478143 A CN 114478143A
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- 239000003337 fertilizer Substances 0.000 title claims abstract description 64
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- 238000013270 controlled release Methods 0.000 title claims abstract description 57
- 238000002360 preparation method Methods 0.000 title claims abstract description 17
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- 238000002156 mixing Methods 0.000 claims abstract description 40
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- 239000002245 particle Substances 0.000 claims abstract description 31
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 26
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- 238000001027 hydrothermal synthesis Methods 0.000 claims abstract description 14
- 238000001035 drying Methods 0.000 claims abstract description 11
- 239000000203 mixture Substances 0.000 claims abstract description 10
- 159000000007 calcium salts Chemical class 0.000 claims abstract description 7
- 238000007598 dipping method Methods 0.000 claims abstract description 6
- 229910021538 borax Inorganic materials 0.000 claims description 24
- 235000010339 sodium tetraborate Nutrition 0.000 claims description 24
- 239000004328 sodium tetraborate Substances 0.000 claims description 24
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical group [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims description 20
- 238000006243 chemical reaction Methods 0.000 claims description 19
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- 229920002261 Corn starch Polymers 0.000 claims description 13
- 239000008120 corn starch Substances 0.000 claims description 13
- -1 polytetrafluoroethylene Polymers 0.000 claims description 13
- 239000007864 aqueous solution Substances 0.000 claims description 11
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 9
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 9
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical group [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 claims description 8
- 239000000243 solution Substances 0.000 claims description 7
- 238000007873 sieving Methods 0.000 claims description 6
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- 239000002253 acid Substances 0.000 claims 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims 1
- 239000001301 oxygen Substances 0.000 claims 1
- 229910052760 oxygen Inorganic materials 0.000 claims 1
- 239000002994 raw material Substances 0.000 abstract description 2
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- 238000011031 large-scale manufacturing process Methods 0.000 abstract 1
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- 235000019698 starch Nutrition 0.000 description 7
- 239000008107 starch Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 238000005520 cutting process Methods 0.000 description 6
- 229920005615 natural polymer Polymers 0.000 description 6
- 238000002791 soaking Methods 0.000 description 6
- 239000012265 solid product Substances 0.000 description 6
- ZHJGWYRLJUCMRT-UHFFFAOYSA-N 5-[6-[(4-methylpiperazin-1-yl)methyl]benzimidazol-1-yl]-3-[1-[2-(trifluoromethyl)phenyl]ethoxy]thiophene-2-carboxamide Chemical compound C=1C=CC=C(C(F)(F)F)C=1C(C)OC(=C(S1)C(N)=O)C=C1N(C1=C2)C=NC1=CC=C2CN1CCN(C)CC1 ZHJGWYRLJUCMRT-UHFFFAOYSA-N 0.000 description 5
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- 238000005563 spheronization Methods 0.000 description 4
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- 230000015572 biosynthetic process Effects 0.000 description 2
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- 239000003999 initiator Substances 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
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- 238000004519 manufacturing process Methods 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
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- 244000043261 Hevea brasiliensis Species 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000004695 Polyether sulfone Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229960000892 attapulgite Drugs 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
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- 238000007334 copolymerization reaction Methods 0.000 description 1
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- MJCSLOQMXMCZMD-UHFFFAOYSA-N dicalcium tetranitrate Chemical compound [Ca++].[Ca++].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O MJCSLOQMXMCZMD-UHFFFAOYSA-N 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000012851 eutrophication Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 230000002262 irrigation Effects 0.000 description 1
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- 238000002386 leaching Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 229910052625 palygorskite Inorganic materials 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 229920006393 polyether sulfone Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000002881 soil fertilizer Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G5/00—Fertilisers characterised by their form
- C05G5/30—Layered or coated, e.g. dust-preventing coatings
- C05G5/37—Layered or coated, e.g. dust-preventing coatings layered or coated with a polymer
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C5/00—Fertilisers containing other nitrates
- C05C5/04—Fertilisers containing other nitrates containing calcium nitrate
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
- C05G3/40—Mixtures of one or more fertilisers with additives not having a specially fertilising activity for affecting fertiliser dosage or release rate; for affecting solubility
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Pest Control & Pesticides (AREA)
- Fertilizers (AREA)
Abstract
The invention discloses a natural latex coated controlled release fertilizer and a preparation method thereof. The method comprises the steps of reacting high-molecular carbohydrate with oxysalt and distilled water in a hydrothermal reaction kettle, uniformly stirring and mixing the obtained modified high-molecular carbohydrate with urea, water-based bentonite and water-soluble calcium salt until a mixture forms wet gel, granulating the obtained wet gel by using a granulator, dipping the obtained wet gel particles in a natural latex solution, dispersing in inorganic dry powder, and finally drying to obtain the coated controlled-release fertilizer. The particle size, the urea content and the urea release rate of the natural latex coated controlled release fertilizer can be regulated, the preparation method is simple, the raw materials are green, the sustainability is high, and the large-scale production is expected to be realized.
Description
Technical Field
The invention belongs to the technical field of fertilizers, and particularly relates to a natural latex coated controlled release fertilizer and a preparation method thereof.
Background
Fertilizers are widely used in the agricultural field because they promote crop growth and increase yield. As the world population continues to grow, the demand for food from human society continues to increase, which leads to exponential growth in the use of fertilizers in the world. Among the three major elements (N, P, K) essential to crops, nitrogen is the most important element for crop growth. Urea is commonly used as a nitrogen-based fertilizer due to its high nitrogen content (46 wt.%) and low cost. However, urea is directly used as a fertilizer, has low utilization rate, cannot be sufficiently absorbed and utilized by crops, and causes environmental problems such as: nitrate leaching, fresh water eutrophication, soil acidification and the like. Multiple periodic applications of crops not only increase labor costs, but also cause fluctuations in the concentration of fertilizer in the soil, which may affect the normal growth of certain crops.
Controlled release fertilizers have received intense attention in recent years because they provide a safer, more economical and more efficient means of providing nutrients. Controlled release fertilizers generally refer to products that contain water-soluble nutrients and whose release in the soil can be controlled by a fertilizer coating. By regulating and controlling the composition and structure of the controlled release fertilizer, the controlled release fertilizer can meet the nutrient supply required by different growth cycles of crops at a more ideal release rate and mode, and can keep the soil fertilizer efficiency for a long time. The fertilizer application efficiency is greatly improved, and the fertilizer application frequency and the labor cost are also reduced. In addition, the controlled release fertilizer can reduce nutrient loss caused by rain wash and soil irrigation, thereby reducing harm to the environment. Currently, coated controlled release fertilizers have been developed that typically employ thermoplastic resins such as: polyethylene, polyurethane, polyethersulfone, and the like as coating materials. However, such coating materials are not only not easily degradable and costly, but also require the use of toxic monomers or solvents. Therefore, there is a need to develop environmentally friendly and safe materials to prepare controlled release fertilizers with superior performance.
At present, the application of biodegradable and environment-friendly natural polymers in controlled release fertilizers has attracted strong attention and research. Natural polymeric materials often do not have sufficient mechanical integrity and other desirable properties needed for controlled release fertilizers and therefore need to work with other materials to form composites. The filling of inorganic minerals (such as bentonite, attapulgite and the like) in natural polymer materials is an important way for improving the controlled release performance of the natural polymer materials. The aim of slowing the release rate of the urea can be achieved through the interaction between the inorganic mineral, the natural polymer and the urea. In addition, the hydrophilic and hydrophobic properties of the natural macromolecule can be adjusted by modification and modification of the natural macromolecule, such as: potassium persulfate is used as an initiator to promote the graft copolymerization of starch and natural rubber, so that the hydrophobicity of the starch is improved and the slow release performance of the coated controlled release fertilizer is improved. However, most of the controlled release fertilizers based on natural polymers have poor controlled release effect and cannot meet the international standard of the controlled release fertilizers. Therefore, there is a need to develop a more economical and efficient way to prepare controlled release fertilizers based on natural polymers.
Natural high molecular carbohydrates (such as starch) can form hydrogel with high water retention capacity, so that the controlled release fertilizer attracts attention. However, the hydrogel is easy to expand rapidly and even gelatinize in the process of water absorption, and is not beneficial to preparing high-performance controlled release fertilizer. Therefore, the invention adopts a kind of oxoacid salt to modify the oxoacid salt, thereby enhancing the oxoacid salt and the metal ions (such as Ca)2+) The chelating ability of the hydrogel is improved, and the purpose of improving the stability of the hydrogel is achieved. Meanwhile, the water-based bentonite is introduced into the hydrogel, so that the water resistance is further enhanced, and the interaction force of the urea and the compound can be improved. Based on the method, the natural latex coated controlled release fertilizer can be prepared by a simple dipping method, and a layer of inorganic powder is processed on the surface of the natural latex coated controlled release fertilizer, so that the adhesion among the coated controlled release fertilizer particles is reduced, and the controlled release fertilizer based on natural macromolecules with better performance is finally obtained.
Disclosure of Invention
The invention aims to provide a natural latex coated controlled-release fertilizer and a preparation method thereof aiming at the defects of the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method of a natural latex coated controlled release fertilizer specifically comprises the following steps:
1) carrying out hydrothermal reaction on natural high-molecular carbohydrate, oxysalt and distilled water in a polytetrafluoroethylene reaction kettle to obtain modified high-molecular carbohydrate;
2) mechanically mixing the modified macromolecular carbohydrate obtained in the step 1) with urea, water-based bentonite and water-soluble calcium salt until the mixture forms wet gel;
3) granulating the wet gel obtained in the step 2) by using a granulator to obtain wet gel particles;
4) dipping the wet gel particles obtained in the step 3) in a natural latex solution, dispersing the dipped wet gel particles in non-hygroscopic inorganic dry powder, uniformly mixing the wet gel particles in the non-hygroscopic inorganic dry powder, sieving the non-hygroscopic inorganic dry powder, and drying the sieved non-hygroscopic inorganic dry powder to obtain the natural latex coated controlled release fertilizer.
Preferably, the natural polymeric carbohydrate is corn starch.
Preferably, the salt of oxyacid is any one of borax, sodium polyphosphate or sodium polymetaphosphate.
Preferably, the water-soluble calcium salt is calcium nitrate, and the inorganic dry powder is calcium sulfate.
The corn starch modification effect of the borax hydrothermal reaction in the invention is influenced by the following factors: borax: the influence of the mass ratio of water, when the amount of borax used is lower or higher, will result in the water stability of the modified wet gel being reduced. Therefore, in the above production method, preferably, the ratio of corn starch: borax: the mass ratio of water is 1.5-3: 1: 2-5.
When borax is used for modifying corn starch, the hydrothermal temperature and time have direct influence on the formation and stability of modified wet gel. Therefore, in the above preparation method, the hydrothermal reaction is preferably carried out at 60 to 200 ℃ for 0.5 to 4 hours.
Further, when the corn starch is subjected to hydrothermal reaction with borax and distilled water in a polytetrafluoroethylene reaction kettle, the following relevant reactions occur:
the apparatus used for the above-mentioned mechanical mixing is not limited, and the order of the mechanical mixing of the respective substances is not particularly limited as long as the respective substances are uniformly stirred and mixed. The purpose of mechanical mixing is to fully disperse urea and bentonite in the modified macromolecular carbohydrate and promote the chelating and crosslinking of water-soluble calcium salt and the modified macromolecular carbohydrate.
Further, carrying out hydrothermal reaction on corn starch, borax and distilled water in a polytetrafluoroethylene reaction kettle to obtain modified high-molecular carbohydrate, and mechanically mixing the modified high-molecular carbohydrate with urea, water-based bentonite and water-soluble calcium salt calcium nitrate, wherein the chelating and crosslinking reaction of the water-soluble calcium salt and the modified high-molecular carbohydrate is as follows:
preferably, the modified polymeric carbohydrate is first mechanically mixed with urea to form a first complex; then mechanically mixing the mixture with water-based bentonite to obtain a second compound; thereafter, it was mechanically mixed with calcium nitrate to obtain a third compound (wet gel).
Extruding the wet gel into strips by a granulator and cutting and granulating, preferably, the size of a die is 1-10mm, and the length of the cut granules is 1-10mm to obtain first granules; and directly soaking the first particles in a natural latex solution to obtain second particles.
The adopted natural latex solution is a mixed solution of natural latex and water, and the ratio of the natural latex to the water has direct influence on the quality of the envelope and the thickness of the envelope. The increased amount of natural latex favors the formation of thicker envelopes, but tends to result in rapid adhesion between particles. Therefore, in the above preparation method, the natural latex aqueous solution preferably has a volume ratio of natural latex to water of 1 to 4:1, mixing and preparing.
Preferably, in the above production method, the immersion time is 5 to 120 seconds.
Preferably, in the above preparation method, the drying temperature is 40-70 deg.C, and the drying time is 1-3 days.
Compared with the prior art, the invention has the advantages that:
1) the method is simple, the raw material source is wide, the biodegradable property is realized, and the green sustainability is strong;
2) a natural latex solution is directly adopted for coating without a catalyst or an initiator;
3) toxic or dangerous organic solvents are not needed, and an aqueous solution impregnation method is adopted, so that the method is economic and environment-friendly;
4) compared with the conventional spraying and coating method, the used dipping method has high utilization rate of the coating solution and can further reduce the cost.
Drawings
FIG. 1 shows the wet gel obtained in example 1.
FIG. 2 shows the wet gel particles obtained in example 1.
FIG. 3 shows the natural latex coated controlled release fertilizer product obtained in example 1.
FIG. 4 shows the borax modified starch wet gel obtained in example 2.
FIG. 5 shows the starch paste obtained in example 3.
FIG. 6 shows the borax modified starch wet gel obtained in example 4.
FIG. 7 shows the natural latex coated controlled release fertilizer product obtained in example 5.
FIG. 8 shows the release rate of the urea in still water in distilled water of the controlled release fertilizer products coated with natural latex obtained in examples 1 and 2 as a function of the standing time. Curve 1: example 1; curve 2: example 2.
Detailed Description
In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.
Example 1
The embodiment provides a preparation method of a natural latex coated controlled release fertilizer, which comprises the following steps:
(1) adding 6g of corn starch, 3g of borax and 10mL of distilled water into a polytetrafluoroethylene reaction kettle at room temperature, stirring and mixing uniformly by using a glass rod, sealing, placing the sealed reaction kettle into a ventilation oven, and carrying out hydrothermal reaction for 2h at 180 ℃ to obtain the borax modified starch wet gel.
(2) Mechanically mixing the borax modified starch wet gel of (1) with 15g of urea uniformly until no obvious urea particles are observed, then adding 3g of water-based bentonite, stirring and mixing uniformly, adding 2.36g of calcium nitrate tetrahydrate, stirring and mixing uniformly until the mixture forms a wet gel again (figure 1).
(3) And (3) adding the wet gel obtained in the step (2) into a granulator, stirring, and carrying out strip forming, cutting and rolling on the stirred wet soft material to obtain wet gel granules, wherein the size of the cross section of the granules is about 4-8mm (shown in figure 2).
(4) And (3) directly dispersing the wet gel particles obtained in the step (3) into a natural latex aqueous solution (the natural latex aqueous solution is prepared by mixing natural latex and water in a volume ratio of 3: 1), soaking for 60 seconds, then carrying out rapid suction filtration, fully oscillating and uniformly mixing the obtained solid product and 50g of calcium sulfate dry powder, and then sieving to remove the redundant calcium sulfate dry powder.
(5) And (3) drying the particles sieved in the step (4) in an oven at 50 ℃ for 2 days to obtain the natural latex coated controlled release fertilizer product (figure 3).
Example 2
The embodiment provides a preparation method of a natural latex coated controlled release fertilizer, which comprises the following steps:
(1) at room temperature, 6g of corn starch, 3g of borax and 10mL of distilled water are added into a polytetrafluoroethylene reaction kettle, a glass rod is used for stirring and mixing uniformly, then the reaction kettle is sealed, the sealed reaction kettle is placed in a ventilation oven, and hydrothermal reaction is carried out for 2h at the temperature of 80 ℃, so that the borax modified starch wet gel (shown in figure 4) is obtained, and as can be seen in the figure, the borax sinks at the bottom of the reaction kettle and does not fully react with the starch.
(2) Mechanically and uniformly mixing the borax modified starch wet gel in the step (1) with 15g of urea until no obvious urea particles are observed, then adding 3g of water-based bentonite, fully stirring and uniformly mixing, then adding 2.36g of calcium nitrate tetrahydrate, fully stirring and uniformly mixing until the mixture forms a wet gel again.
(3) And (3) adding the wet gel obtained in the step (2) into a granulator, stirring, and carrying out strip forming, cutting and spheronization on the stirred wet soft material to obtain wet gel granules, wherein the size of the cross section of the granules is about 4-8 mm.
(4) And (4) directly dispersing the wet gel particles obtained in the step (3) into a natural latex aqueous solution (the natural latex aqueous solution is prepared by mixing natural latex and water in a volume ratio of 3: 1), soaking for 60 seconds, then performing rapid suction filtration, fully oscillating and uniformly mixing the obtained solid product and 50g of calcium sulfate dry powder, and then sieving to remove the redundant calcium sulfate dry powder.
(5) And (5) drying the particles sieved in the step (4) in an oven at 50 ℃ for 2d to obtain the natural latex coated controlled release fertilizer product.
Example 3
The embodiment provides a preparation method of a natural latex coated controlled release fertilizer, which comprises the following steps:
(1) adding 6g of corn starch and 10mL of distilled water into a polytetrafluoroethylene reaction kettle at room temperature, stirring and mixing uniformly by using a glass rod, sealing, placing the sealed reaction kettle into a ventilation oven, and carrying out hydrothermal reaction for 2h at 80 ℃ to obtain starch paste (shown in figure 5), wherein the corn starch and the distilled water do not form wet gel through the hydrothermal reaction.
(2) Mechanically mixing the starch paste of (1) with 15g of urea until no obvious urea particles are observed, adding 3g of aqueous bentonite thereto, stirring and mixing well, adding 2.36g of calcium nitrate tetrahydrate, and stirring and mixing well until the mixture forms a wet gel.
(3) And (3) adding the wet gel obtained in the step (2) into a granulator, stirring, and carrying out strip forming, cutting and spheronization on the stirred wet soft material to obtain wet gel granules, wherein the size of the cross section of the granules is about 4-8 mm.
(4) And (3) directly dispersing the wet gel particles obtained in the step (3) into a natural latex aqueous solution (the natural latex aqueous solution is prepared by mixing natural latex and water in a volume ratio of 3: 1), soaking for 60 seconds, then carrying out rapid suction filtration, fully oscillating and uniformly mixing the obtained solid product and 50g of calcium sulfate dry powder, and then sieving to remove the redundant calcium sulfate dry powder.
(5) And (5) drying the particles sieved in the step (4) in an oven at 50 ℃ for 2d to obtain the natural latex coated controlled release fertilizer product.
Example 4
The embodiment provides a preparation method of a natural latex coated controlled release fertilizer, which comprises the following steps:
(1) at room temperature, 6g of corn starch, 3g of borax and 10mL of distilled water are added into a polytetrafluoroethylene reaction kettle, a glass rod is used for stirring and mixing uniformly, then the reaction kettle is sealed, the sealed reaction kettle is placed in a ventilation oven, and hydrothermal reaction is carried out for 6h at 180 ℃, so that the borax modified starch wet gel (figure 6) is obtained, and as can be seen in the figure, the stability of the wet gel is poor.
(2) Mechanically and uniformly mixing the borax modified starch wet gel in the step (1) with 15g of urea until no obvious urea particles are observed, then adding 3g of water-based bentonite, fully stirring and uniformly mixing, then adding 2.36g of calcium nitrate tetrahydrate, fully stirring and uniformly mixing until the mixture forms a wet gel again.
(3) And (3) adding the wet gel obtained in the step (2) into a granulator, stirring, and carrying out strip forming, cutting and spheronization on the stirred wet soft material to obtain wet gel granules, wherein the size of the cross section of the granules is about 4-8 mm.
(4) And (3) directly dispersing the wet gel particles obtained in the step (3) into a natural latex aqueous solution (the natural latex aqueous solution is prepared by mixing natural latex and water in a volume ratio of 3: 1), soaking for 60 seconds, then carrying out rapid suction filtration, fully oscillating and uniformly mixing the obtained solid product and 50g of calcium sulfate dry powder, and then sieving to remove the redundant calcium sulfate dry powder.
(5) And (5) drying the particles sieved in the step (4) in an oven at 50 ℃ for 2d to obtain the natural latex coated controlled release fertilizer product.
Example 5
The embodiment provides a preparation method of a natural latex coated controlled release fertilizer, which comprises the following steps:
(1) adding 6g of corn starch, 3g of borax and 10mL of distilled water into a polytetrafluoroethylene reaction kettle at room temperature, stirring and mixing uniformly by using a glass rod, sealing, placing the sealed reaction kettle into a ventilation oven, and carrying out hydrothermal reaction for 6h at 180 ℃ to obtain the borax modified starch wet gel.
(2) Mechanically and uniformly mixing the borax modified starch wet gel in the step (1) with 15g of urea until no obvious urea particles are observed, then adding 3g of water-based bentonite, fully stirring and uniformly mixing, then adding 2.36g of calcium nitrate tetrahydrate, fully stirring and uniformly mixing until the mixture forms a wet gel again.
(3) And (3) adding the wet gel obtained in the step (2) into a granulator, stirring, and carrying out strip forming, cutting and spheronization on the stirred wet soft material to obtain wet gel granules, wherein the size of the cross section of the granules is about 4-8 mm.
(4) And (4) directly dispersing the wet gel particles obtained in the step (3) into natural latex, soaking for 60 seconds, then carrying out rapid suction filtration, and collecting a solid product.
(5) And (3) drying the solid product obtained in the step (4) in an oven at 50 ℃ for 2d to obtain the natural latex coated controlled release fertilizer product (figure 7), wherein the natural latex coated controlled release fertilizer product is mutually sticky.
10g of the natural latex coated controlled-release fertilizer product obtained in example 1 and 10g of the natural latex coated controlled-release fertilizer product obtained in example 2 were soaked in 100mL of distilled water, and the change of the release rate of the urea in the still water with the standing time was measured, and the result is shown in FIG. 8.
The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.
Claims (10)
1. A preparation method of a natural latex coated controlled release fertilizer is characterized by comprising the following steps: the method comprises the following steps:
1) carrying out hydrothermal reaction on the macromolecular carbohydrate, oxysalt and distilled water in a polytetrafluoroethylene reaction kettle to obtain modified macromolecular carbohydrate;
2) uniformly stirring and mixing the modified macromolecular carbohydrate obtained in the step 1) with urea, water-based bentonite and water-soluble calcium salt until a mixture forms wet gel;
3) granulating the wet gel obtained in the step 2) by using a granulator to obtain wet gel particles;
4) dipping the wet gel particles obtained in the step 3) in a natural latex solution, dispersing the dipped wet gel particles in inorganic dry powder, vibrating and mixing the particles uniformly, then sieving the particles to remove redundant dry powder, and finally drying the particles to obtain the natural latex coated controlled release fertilizer.
2. The method for preparing the natural latex coated controlled-release fertilizer according to claim 1, wherein the method comprises the following steps: in the step 1), the macromolecular carbohydrate is corn starch.
3. The method for preparing the natural latex coated controlled-release fertilizer according to claim 1, wherein the method comprises the following steps: in the step 1), the oxysalt is any one of borax, sodium polyphosphate or sodium polymetaphosphate.
4. The method for preparing the natural latex coated controlled-release fertilizer according to claim 1, wherein the method comprises the following steps: in step 1), the polymeric carbohydrate: an oxygen acid salt: the mass ratio of the distilled water is 1: 0.1-0.5: 1-5, the conditions of the hydrothermal reaction are 60-200 ℃ and 0.5-4 h.
5. The method for preparing the natural latex coated controlled-release fertilizer according to claim 1, wherein the method comprises the following steps: in the step, the water-soluble calcium salt is calcium nitrate.
6. The method for preparing the natural latex coated controlled-release fertilizer according to claim 1, wherein the method comprises the following steps: in step 2), the urea: water-based bentonite: calcium nitrate: the mass ratio of the wet gel is 1: 1-3: 4-8.
7. The method for preparing the natural latex coated controlled-release fertilizer according to claim 1, wherein the method comprises the following steps: in the step 4), the natural latex aqueous solution is prepared by mixing the following natural latex: the volume ratio of the distilled water is 1-4: 1.
8. The method for preparing the natural latex coated controlled-release fertilizer according to claim 1, wherein the method comprises the following steps: in the step 4), the inorganic dry powder is calcium sulfate.
9. The method for preparing the natural latex coated controlled-release fertilizer according to claim 1, wherein the method comprises the following steps: in the step 4), the dipping time is 5-120 seconds, and the drying condition is 40-70 ℃ and 1-3 days.
10. The natural latex coated controlled release fertilizer prepared by the preparation method of claim 1.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB807505A (en) * | 1953-03-06 | 1959-01-14 | Starch Products Ltd | Improvements in adhesive compositions |
| US5516520A (en) * | 1992-07-31 | 1996-05-14 | Industrial Technology Research Institute | Controlled-release pesticides and methods for preparation and use thereof |
| JP2001251975A (en) * | 2000-03-11 | 2001-09-18 | Shihoro Tekko Kk | Agricultural degradable mulch film and its laying method |
| US20060148646A1 (en) * | 2004-09-23 | 2006-07-06 | Taylor Pursell | Controlled release fertilizers containing calcium sulfate and processes for making same |
| WO2009021385A1 (en) * | 2007-08-15 | 2009-02-19 | Shandong Kingenta Ecological Engineering Co., Ltd. | Aqueous polymer coated controlled release fertilizer friendly to environment and preparation thereof |
| CN105358506A (en) * | 2013-05-24 | 2016-02-24 | 领袖化学有限公司 | Method for manufacturing sustained-release matrix-type granular complex fertilizer and matrix-type granular complex fertilizer obtained therefrom |
| CN111035015A (en) * | 2019-12-27 | 2020-04-21 | 浙江新和成股份有限公司 | Water-insoluble fat-soluble nutrient microcapsule and preparation method thereof |
-
2022
- 2022-03-07 CN CN202210216437.3A patent/CN114478143A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB807505A (en) * | 1953-03-06 | 1959-01-14 | Starch Products Ltd | Improvements in adhesive compositions |
| US5516520A (en) * | 1992-07-31 | 1996-05-14 | Industrial Technology Research Institute | Controlled-release pesticides and methods for preparation and use thereof |
| JP2001251975A (en) * | 2000-03-11 | 2001-09-18 | Shihoro Tekko Kk | Agricultural degradable mulch film and its laying method |
| US20060148646A1 (en) * | 2004-09-23 | 2006-07-06 | Taylor Pursell | Controlled release fertilizers containing calcium sulfate and processes for making same |
| WO2009021385A1 (en) * | 2007-08-15 | 2009-02-19 | Shandong Kingenta Ecological Engineering Co., Ltd. | Aqueous polymer coated controlled release fertilizer friendly to environment and preparation thereof |
| CN105358506A (en) * | 2013-05-24 | 2016-02-24 | 领袖化学有限公司 | Method for manufacturing sustained-release matrix-type granular complex fertilizer and matrix-type granular complex fertilizer obtained therefrom |
| CN111035015A (en) * | 2019-12-27 | 2020-04-21 | 浙江新和成股份有限公司 | Water-insoluble fat-soluble nutrient microcapsule and preparation method thereof |
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Application publication date: 20220513 |