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Coated slow-release urea and its preparation method

A slow-release urea and coating technology, which is applied in the field of coated slow-release urea and its preparation, can solve the problems of short sustained-release time and the like

Inactive Publication Date: 2006-10-25
NANJING UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0013] 2. The coating material must be biodegradable, that is, the coating material left in the soil after release can be degraded or decomposed by microorganisms;
At present, although there are research literature reports on this kind of resin-coated slow-release nitrogen fertilizer in China, the slow-release time is generally short, so it has not been popularized and applied.

Method used

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  • Coated slow-release urea and its preparation method
  • Coated slow-release urea and its preparation method
  • Coated slow-release urea and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045]Take 1 kg of cylindrical urea of ​​10×4mm, place it in the coating pan of the coating machine, and adjust the rotating speed at about 500 rpm. Set the wind temperature at 50°C, and heat the temperature of the flake urea to 40°C. Put 200mL of acidic formaldehyde solution in the feeding barrel of the coating machine, open the spray gun to spray the formaldehyde solution, when the surface of urea flakes becomes sticky, stop spraying until the surface of the flakes is dry. At this time, the spray gun is opened again to spray formaldehyde solution, and a new round of reaction coating cycle is carried out. Reciprocate in this way until the required amount of formaldehyde solution is sprayed and the surface of the sheet is dry. The whole process takes about 4 hours, and the formed coating layer accounts for about 10% of the total mass of the fertilizer. Finally, soak the dried urea flakes in tung oil for about 10 days, and then dry to obtain sample 1.

Embodiment 2

[0047] Take 1 kg of cylindrical urea of ​​10×4mm, place it in the coating pan of the coating machine, and adjust the rotating speed at about 500 rpm. Set the wind temperature at 50°C, and heat the temperature of the flake urea to 40°C. Put 300mL of acidic formaldehyde solution in the feeding barrel of the coating machine, open the spray gun to spray formaldehyde solution, when the surface of urea flakes becomes sticky, stop spraying until the surface of the flakes is dry. At this time, the spray gun is opened again to spray formaldehyde solution, and a new round of reaction coating cycle is carried out. Reciprocate in this way until the required amount of formaldehyde solution is sprayed and the surface of the sheet is dry. The whole process takes about 6 hours, and the formed coating layer accounts for about 15% of the total mass of the fertilizer. Finally, soak the dried urea flakes in tung oil for about 10 days, and then dry to obtain sample 2.

[0048] The dissolution ...

Embodiment 3

[0054] Preparation of surface treatment agent: Take 12.5g of phenol, heat it to melt, add 8.5ml of tung oil, several drops of concentrated sulfuric acid, and react at 100°C-115°C for 2 hours. Add concentrated ammonia water to adjust the pH ≈ 8.5, add 8ml of formaldehyde, react at 75°C to 85°C for 2 hours, and dehydrate under reduced pressure.

[0055] The surface treatment agent obtained by this embodiment 3 is called tung oil modified phenolic resin 1.

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Abstract

The invention provides a coated slow-release urea, which is composed of a core layer and a coating layer, wherein the core layer is a sheet-shaped water-soluble urea, and the coating layer is a slightly soluble urea-formaldehyde resin. The weight of the core layer accounts for The total weight of the film-type slow-release urea is 85%-95%, and the weight of the coating layer accounts for 5%-15% of the total weight of the film-type slow-release urea. The slow-release urea uses the idea of ​​wrapping fertilizer with fertilizer. After the urea is pressed into tablets by a tablet press, the acidic formaldehyde solution is directly sprayed through the coating machine to react with the surface of the sheet-shaped urea to form a film, and finally the surface of the film is hydrophobically modified. manufacture. It not only has a simple manufacturing method and low cost, but also its coating material can be decomposed by microorganisms in the soil into nutrients that can be absorbed by plants, so it is an environmentally friendly slow-release fertilizer.

Description

technical field [0001] The invention belongs to the technical field of fertilizers, and relates to an environment-friendly slow-release fertilizer capable of controlling the slow release of urea, in particular to a coated slow-release urea and a preparation method thereof. Background technique [0002] As a kind of nitrogen fertilizer with the highest nitrogen content and the largest amount of use, urea plays a pivotal role in the industrial and agricultural production of various countries. However, the utilization rate of urea is surprisingly low, generally only 30% to 40%. This high-consumption and low-efficiency nitrogen fertilizer not only leads to a huge waste of resources, but also deteriorates the ecological environment, endangers human survival and health, and affects the quality and yield of crops. As countries pay more and more attention to ecological environment protection and the implementation of sustainable economic development strategies, improving the effici...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C05C9/00C05G3/00
Inventor 殷以华王治流杨琥程镕时周建民
Owner NANJING UNIV