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Production method of urea formaldehyde slow-release nitrogen fertilizer

A production method, urea-formaldehyde technology, applied in the direction of nitrogen fertilizer, phosphate fertilizer, fertilization equipment, etc., can solve the problems of poor slow-release effect, complicated production process, difficult industrialization, etc.

Pending Publication Date: 2021-10-12
GUIZHOU RES INST OF CHEM IND +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, urea-formaldehyde fertilizer has limited its application in agriculture especially on field crops due to the following major problems: 1. The production cost of urea-formaldehyde slow-release fertilizer is too high, generally 3-8 times that of conventional fertilizers, resulting in Most of urea-formaldehyde is only suitable for vegetables, flowers, lawns and other crops with high economic value; 2. The production process of urea-formaldehyde slow-release fertilizer is more complicated than the traditional process, and the production cycle is long. The research on key equipment and process matching is relatively weak, and it is difficult to Form industrialization; 3. The product quality is unstable, easy to agglomerate, and the slow-release effect is poor

Method used

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  • Production method of urea formaldehyde slow-release nitrogen fertilizer
  • Production method of urea formaldehyde slow-release nitrogen fertilizer
  • Production method of urea formaldehyde slow-release nitrogen fertilizer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] The production method of urea-formaldehyde slow-release nitrogen fertilizer, the steps are as follows:

[0067] (1) Mix urea and a formaldehyde solution with a mass concentration of 35%, stir and add solid sodium hydroxide to adjust the pH of the mixed solution to 8; wherein the molar ratio of urea to formaldehyde is 2:1;

[0068] (2) The temperature of the mixed solution was raised to 50°C, and after the reaction was continued for 30 minutes, monoammonium phosphate was added to adjust the pH value of the reaction system to 3.5;

[0069] (3) After the solution system obtained in step (2) is solidified, age at room temperature for 12 hours;

[0070] (4) The aged urea-formaldehyde is dried in spin flash drying, the inlet temperature is 280-310°C, the product is collected in a settling chamber, and the product is recovered by cyclone separation and dust removal, and the tail gas is treated and then emptied.

Embodiment 2

[0072] The production method of urea-formaldehyde slow-release nitrogen fertilizer, the steps are as follows:

[0073] (1) Mix urea and a formaldehyde solution with a mass concentration of 40%, stir and add sodium hydroxide to adjust the pH of the mixed solution to 9; wherein the molar ratio of urea to formaldehyde is 1.5:1;

[0074] (2) The temperature of the mixed solution was raised to 40°C, and after the reaction was continued for 40 minutes, urea phosphate was added to adjust the pH value of the reaction system to 4.0;

[0075] (3) After the solution system obtained in step (2) is solidified, age at room temperature for 12 hours;

[0076] (4) The aged urea-formaldehyde is sent to the spin flash dryer for drying, the inlet temperature is 280-310°C, the product is collected in a settling chamber, and the product is recovered by cyclone separation and dust removal, and the tail gas is treated and then emptied.

Embodiment 3

[0078] The production method of changing urea-formaldehyde slow-release nitrogen fertilizer, the steps are as follows:

[0079] (1) Mix urea with a formaldehyde solution with a mass concentration of 50%, stir and add solid sodium hydroxide to adjust the pH of the mixed solution to 9; wherein the molar ratio of urea to formaldehyde is 1.8:1;

[0080] (2) The temperature of the mixed solution was raised to 45°C, and after the reaction was continued for 50 minutes, phosphoric acid was added to adjust the pH value of the reaction system to 4.5;

[0081] (3) After the solution system obtained in step (2) is solidified, age at room temperature for 12 hours;

[0082] (4) The aged urea-formaldehyde is sent to the spin flash dryer for drying, the inlet temperature is 280-310°C, the product is collected in a settling chamber, and the product is recovered by cyclone separation and dust removal, and the tail gas is treated and then emptied.

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Abstract

The invention belongs to the technical field of fertilizers, and particularly relates to a production method of a urea formaldehyde slow-release nitrogen fertilizer, which comprises the following steps: (1) mixing urea and a formaldehyde solution, stirring, adding a sodium hydroxide solid to adjust the pH value of the mixed solution to be alkaline, heating the mixed solution to a certain temperature, and continuously reacting for a certain time; (2) continuously discharging the reaction liquid in the step (1) to a conveyor belt type polymerization tank in a normal operation state, synchronously adding a regulator to regulate the pH value of the reaction liquid on the conveyor belt type polymerization tank to be acidic, and polymerizing to generate urea formaldehyde; (3) aging the urea formaldehyde produced in the step (2) for more than 12 hours; and (4) drying the aged urea formaldehyde in a rotary flash dryer, collecting a product by adopting a settling chamber, recycling the product through cyclone separation and dust removal, and emptying after tail gas treatment. The industrial production method of the urea formaldehyde, provided by the invention, has the characteristics that a process technology for continuously producing the urea formaldehyde slow-release fertilizer is provided, a powdery urea formaldehyde slow-release fertilizer product can be directly produced, the production process is simple, and the quality is stable.

Description

technical field [0001] The invention belongs to the technical field of fertilizers, in particular to a production method of urea-formaldehyde slow-release nitrogen fertilizer. Background technique [0002] Urea-formaldehyde fertilizer is a urea-formaldehyde polymer with relatively low solubility obtained by two-step reaction of urea and formaldehyde through hydroxylation addition reaction and methyleneation condensation reaction under certain conditions. Urea-formaldehyde fertilizer is a long-acting nitrogen fertilizer with good physical properties and slow-release properties. After it is applied to the soil, it releases its nutrients slowly under the dual effects of hydrolysis and microbial attack, prolonging the fertilizer effect period and high utilization rate; and it can Promote the formation of soil aggregate structure, improve soil permeability and increase root penetration of crops. The popularization and application of urea-formaldehyde fertilizer has far-reaching ...

Claims

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Application Information

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IPC IPC(8): C05G3/40C05C9/02C05G3/90
CPCC05B7/00C05C9/02C05G3/40C05G3/90C05B17/00C05C9/00Y02P60/21
Inventor 陈文兴周昌平田娟陈思帆王瑶虞江
Owner GUIZHOU RES INST OF CHEM IND