Method and stirring device for producing crystalline monoammonium phosphate by using wet method to purify phosphoric acid

A monoammonium phosphate, wet purification technology, applied in the direction of phosphate, phosphorus oxyacids, etc., can solve the problems of high purity crystal monoammonium phosphate, unsatisfactory purity, long crystallization time, etc., to achieve good appearance quality, Good crystallization effect, good product crystallization effect

Active Publication Date: 2016-06-01
WENGFU DAZHOU CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The process is complex and costly
At the same time, in the process of producing monoammonium phosphate by thermal phosphoric acid, the power consumption is high, the mixing effect is poor, the crystallization time is long, and the effect is not ideal
[0011] The cost of producing crystalline monoammonium phosphate by wet process phosphoric acid is relatively low, but its product purity is not as high as that of crystalline monoammonium phosphate produced by thermal process phosphoric acid. Even after the subsequent purification process, its purity is still not ideal

Method used

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  • Method and stirring device for producing crystalline monoammonium phosphate by using wet method to purify phosphoric acid
  • Method and stirring device for producing crystalline monoammonium phosphate by using wet method to purify phosphoric acid
  • Method and stirring device for producing crystalline monoammonium phosphate by using wet method to purify phosphoric acid

Examples

Experimental program
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Effect test

Embodiment 1

[0073] A method for producing crystalline monoammonium phosphate by wet purification of phosphoric acid, comprising the following steps:

[0074] (1) After adding a preset amount of mother liquor in the neutralization tank, add purified wet-process phosphoric acid with a metered purity of 85% and mix until the mass concentration of phosphoric acid in the mixed solution is 35-45%;

[0075] (2) Start the stirring device, add ammonia to neutralize by adding liquid ammonia at multiple points, control the speed of adding liquid ammonia, and continue adding for 80-100 minutes until the pH value of the solution reaches 4.2-4.6, stop neutralization;

[0076] (3) After passing the test, enter the cooling and crystallization stage;

[0077] (4) After the crystallization is completed, the slurry is dehydrated and dried to obtain crystalline monoammonium phosphate, and the detached mother liquor is sent to the mother liquor storage tank for recycling.

Embodiment 2

[0079] A method for producing crystalline monoammonium phosphate by wet purification of phosphoric acid, comprising the following steps:

[0080] (1) After adding a preset amount of mother liquor in the neutralization tank, add purified wet-process phosphoric acid with a metered purity of 85% and mix until the mass concentration of phosphoric acid in the mixed solution is 40%;

[0081] (2) Start the stirring device, add liquid ammonia to neutralize by adding ammonia at multiple points, control the speed of adding liquid ammonia, continue adding for 90 minutes until the pH value of the solution reaches 4.3, and stop neutralization;

[0082] (3) After passing the test, enter the cooling and crystallization stage; when starting to cool, use natural cooling; when the slurry temperature drops to 70°C, turn on the reactor jacket cooling water for forced cooling; until the temperature drops to normal temperature, the cooling time The control is 90 minutes.

[0083] (4) After the cry...

Embodiment 3

[0085]The stirring device used in the method for producing crystalline monoammonium phosphate by using wet purification phosphoric acid is characterized in that it includes a stirring bin and a stirring paddle; shaft 3, and the stirring blades arranged on the fixed shaft 3;

[0086] The stirring paddle is provided with a first stirring paddle 1 and a second stirring paddle 2, both sleeved on the fixed shaft 3; the blade surface of the first stirring paddle 1 is horizontal and in an "L" shape structure, one end of which is fixedly connected to the central shaft, and the other end extends horizontally; the blade of the second stirring paddle 2 is arc-shaped, one end of which is fixedly connected to the central shaft, and the other end extends horizontally.

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Abstract

The invention relates to the field of preparation of monoammonium phosphate, particularly a method and stirring device for producing crystalline monoammonium phosphate by using wet-process purified phosphoric acid. The method cancels the pretreatment technique required by hot-process phosphoric acid, saves the investment and simplifies the operation. The method comprises the following steps: (1) adding a preset amount of mother solution into a neutralizing tank, and adding metered purified wet-process phosphoric acid with the purity of 85% until the mass concentration of phosphoric acid in the mixed solution is 35-45%; (2) starting a stirring device, adding liquid ammonia for neutralization by multipoint ammonification, continuously adding the liquid ammonia for 80-100 minutes while controlling the liquid ammonia addition speed, and stopping neutralization when the pH value reaches 4.2-4.6; (3) sending the qualified product into a cooling crystallization stage; and (4) after finishing crystallization, dehydrating and drying the slurry to obtain crystalline monoammonium phosphate, and sending the mother solution to a mother solution storage tank for cyclic use.

Description

technical field [0001] The invention relates to the field of preparation of monoammonium phosphate, in particular to a method and a stirring device for producing crystalline monoammonium phosphate by using wet method to purify phosphoric acid. Background technique [0002] Ammoniumdihydrogenphosphate; Ammoniumphosphate, monobasic, molecular formula: NH 4 h 2 PO 4 Molecular weight: 115.03 Monoammonium phosphate is also called ammonium dihydrogen phosphate. Colorless transparent tetragonal crystal, density 1.803 (19°C). Melting point 190°C, easily soluble in water, slightly soluble in alcohol, insoluble in acetone. The aqueous solution is acidic, suitable for feed additives and high-efficiency compound fertilizers. [ [0003] Monoammonium phosphate (MAP) is a water-soluble quick-acting compound fertilizer, available phosphorus (AP 2 o 5 ) to total nitrogen (TN) content ratio of about 5.44:1, is one of the main varieties of high-concentration phosphorus compound fertili...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/28
Inventor 刘立锋伍泽绵陈刚
Owner WENGFU DAZHOU CHEM CO LTD
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