Synthesis of urea-formaldehyde controlled releasing fertilizer

A technology of controlled release fertilizer and synthesis method, applied in fertilizer mixture, nitrogen fertilizer, fertilization device and other directions, can solve the problems of long slow release period, easy overflow of formaldehyde, poor uniformity, etc., to improve effectiveness, improve environmental quality and production Efficiency, quality improvement effect

Inactive Publication Date: 2004-06-23
北京市农林科学院植物营养与资源研究所
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Problems solved by technology

[0004] Formaldehyde is easy to overflow during the polymerization process; unreacted urea has no slow-release effect during the polymerization process: the uniformity of the polymerization reactant in the synthesis of the concentrated solution is poor, and the violent polymerization reaction is prone to occur (the local concentration is too high to cause the cross-linking reaction of the condensation polymer, affect the effectiveness of the polymer); the slow-release period of urea-formaldehyde slow-acting fertilizer is long, which affects the availability of polymer nitrogen, and the slow-release process of granular and powder is not much different

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0026] The preparation process of the urea-formaldehyde controlled-release fertilizer of this example is as follows:

[0027] 1. Weigh 20.0g of flour and add it to a 1000ml beaker, add 240.0g of water, heat to boiling, and keep warm for 5min;

[0028] 2. After stopping heating, 272.0g urea is directly added in the solution of step (1);

[0029] 3. Put the beaker in a constant temperature water bath at 60°C. When the urea is completely dissolved, add 170ml of formaldehyde solution (37%) into the solution at an even speed (add 1.7g of polyacrylamide water-absorbing resin to the 170ml of formaldehyde solution in advance, after completely absorbing use);

[0030] 4. Measure the pH value and adjust the pH of the solution to 8.0 with 10% NaOH, then add 50ml of cottonseed oil to cover the surface of the solution, stir gently and place it in a water bath, when the temperature of the solution rises to 60°C, start timing , keep warm for 40min;

[0031] 5. Weighing 60g zeolite powder ...

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Abstract

The synthesis process of urea-formaldehyde controlled releasing fertilizer includes mixing gelatinized starch and urea, adding the mixture of polymer water absorbing resin and formaldehyde solution, adding vegetable oil, organic matter including turf and stalk and adsorbent including zeolite, adding sulfuric acid for acidifying to obtain solid product, and final drying, crushing and sieving to obtain the product. The said process avoids excessive crosslinking of polymer to raise the utility of nitrogen, avoids volatizing of formaldehyde during reaction to raise environment quality and production efficiency, and adds zeolite and other inorganic stuffing to raise product quality and provide water maintaining and fertilizer maintaining function and trace elements. In addition, phosphate fertilizer and potash fertilizer may be also added to produce re-compounded fertilizer.

Description

technical field [0001] The invention relates to a method for manufacturing chemical fertilizers, more specifically a method for synthesizing urea-formaldehyde controlled-release fertilizers. Background technique [0002] Urea-formaldehyde, also known as urea-formaldehyde fertilizer, was produced by BASF in 1955 and was the first commercially produced slow-release fertilizer. Urea-formaldehyde is formed by the condensation of urea and formaldehyde, and it is white, odorless powder or granule. According to the molar ratio (U / F) of urea to formaldehyde, urea-formaldehyde fertilizers with different degrees of condensation can be prepared. Usually, the preparation process of urea-formaldehyde fertilizer: urea and formaldehyde are added into the reactor in a certain proportion to make the urea excess to prevent excessive polymerization. Usually, the molar ratio of urea to formaldehyde is controlled to be greater than 1:1, and the solution is adjusted to be alkaline with NaOH, Re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C05C9/02C05G3/00C08G12/12
Inventor 邢礼军李亚星徐秋明王幼珊倪小会
Owner 北京市农林科学院植物营养与资源研究所
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