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Preparation of low aldehyde long-acting urea-formaldehyde slow release fertilizer

A slow-release and long-acting technology of urea-formaldehyde, applied in nitrogen fertilizers, fertilization devices, urea compound fertilizers, etc., can solve the problems of damage to the health of users, escape of formaldehyde, health threats to transporters and warehouse managers, etc., and achieve long-term fertilizer efficiency. , Improve the activity index, the effect of high activity index

Active Publication Date: 2009-01-28
CNOOC FUDAO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When storing or using this kind of urea-formaldehyde slow-release fertilizer with high free formaldehyde content, a large amount of formaldehyde will escape, which will seriously pollute the environment and damage the health of users, especially in places where urea-formaldehyde slow-release fertilizer is stored, due to the continuous release of formaldehyde and The accumulation in the environment makes the concentration of formaldehyde in the air high, posing a threat to the health of movers and warehouse managers

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Prepare raw materials: 100 parts of urea, 52 parts of 37% formaldehyde. Take 800 parts of water, add 100 parts of urea, stir, add 20% sulfuric acid to adjust the pH to 1.7, and adjust the temperature to 25°C. Add 52 parts of 37% formaldehyde solution, and adjust the pH to 6.5 with 100 g / L NaOH solution immediately after reacting for 30 minutes. The solution is cooled to 25° C., filtered, and dried to obtain columnar urea-formaldehyde slow-release fertilizer granules with lateral pressure in the range of 40-50 N / CM.

[0015] The main technical indicators of the obtained urea-formaldehyde slow-release fertilizer are: total nitrogen content: 36.5%; water-soluble nitrogen content: 11.0%; cold-water insoluble nitrogen: 25.5%; activity coefficient: 41%; free formaldehyde content: 0.78%. The urea-formaldehyde slow-release fertilizer granules are soaked in still water at 25° C. for 7 days, and the granules are cracked. The initial (24 hours) nutrient release rate is 12%, and i...

Embodiment 2

[0017] Prepare raw materials: 100 parts of urea, 1 part of melamine, 52 parts of 37% formaldehyde, ammonia gas. Take 800 parts of water, add 100 parts of urea and 1 part of melamine, stir, add 20% sulfuric acid to adjust the pH to 1.7, and adjust the temperature to 25°C. After the solid reactant was dissolved, 52 parts of 37% formaldehyde solution was added, and after reacting for 30 minutes, the pH was adjusted to 6.5 with 100 g / L NaOH solution. Open the decompression valve, and feed 0.5 parts of ammonia as an aldehyde remover within 20 minutes under stirring conditions. The solution is cooled to 25° C., filtered, and dried to obtain columnar urea-formaldehyde slow-release fertilizer granules with lateral pressure in the range of 40-50 N / CM.

[0018] The main technical indicators of the obtained urea-formaldehyde slow-release fertilizer are: total nitrogen content: 36.7%; water-soluble nitrogen content: 10.8%; cold-water insoluble nitrogen: 25.9%; activity coefficient: 44%. ...

Embodiment 3

[0020] Prepare raw materials: 100 parts of urea, 5 parts of phenol, 52 parts of 37% formaldehyde, 27% hydrogen peroxide. Take 800 parts of water, add 100 parts of urea and 5 parts of phenol, stir, add 20% sulfuric acid to adjust the pH to 1.7, and adjust the temperature to 25°C. After the solid reactant was dissolved, 52 parts of 37% formaldehyde solution was added, and after reacting for 30 minutes, the pH was adjusted to 6.5 with 100 g / L NaOH solution. Then add 1.5 parts of aldehyde removing agent 27% hydrogen peroxide under stirring condition, stop stirring after 20 minutes. The solution is cooled to 25° C., filtered, and dried to obtain columnar urea-formaldehyde slow-release fertilizer granules with lateral pressure in the range of 40-50 N / CM. The free formaldehyde content of the urea-formaldehyde slow-release fertilizer is 0.012%. After soaking in still water at 25°C for 42 days, the particles disintegrated.

[0021] The main technical indicators of the obtained urea-...

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Abstract

The invention discloses a preparation method of a low aldehyde long-acting slow-release urea formaldehyde fertilizer. The method comprises the following steps: urea aqueous solution and formaldehyde aqueous solution are prepared, then added with an active assistant, after the solution is stable, the PH value of the solution is regulated to 0.9-4.5, after polymerization is finished, the PH value of the solution is regulated to 6.5-7.5, then the solution is added with an aldehyde removing agent, and after the solution is cooled to the room temperature, the suspension is filtrated, the filtrate obtained is collected for recycling, and the low aldehyde long-acting slow-release urea formaldehyde fertilizer is obtained after a filter cake is dried, crushed and prilled. The method has simple process, effectively reduces the release rate of cold water soluble nutrients of the low urea formaldehyde slow-release fertilizer particles by the active assistant and the aldehyde removing agent, reduces the content of free formaldehyde, and increases the active index of the slow-release urea formaldehyde fertilizer, and provides the slow-release urea formaldehyde fertilizer with low formaldehyde content, high activity index and long fertilizer effect for crop growing.

Description

technical field [0001] The invention relates to a preparation method of a urea-formaldehyde slow-release fertilizer, in particular to a preparation method of a low-formaldehyde low-formaldehyde long-acting urea-formaldehyde slow-release fertilizer. Background technique [0002] Urea-formaldehyde slow-release fertilizer is a condensate of urea and formaldehyde, a general term for solid fertilizers that provide slow-release nitrogen nutrients for plant growth. The production method of urea-formaldehyde slow-release fertilizer also has two kinds of one-step method and two-step method. The one-step method is the direct condensation of urea and formaldehyde under acidic conditions. The two-step method is to firstly generate hydroxymethylene urea from urea and formaldehyde under alkaline conditions, and then condense hydroxymethylene urea with urea under acidic conditions to obtain urea-formaldehyde slow-release fertilizer. [0003] U.S. Patent US2644806 introduces a one-step sy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C05C9/02
Inventor 赵福军李子芬傅送保姚光前梁明初曲均峰郭涛王亮亮
Owner CNOOC FUDAO
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