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Method for crystallizing large-grained industrial ammonium dihydrogen phosphate

An industrial-grade monoammonium phosphate technology, which is applied in the direction of phosphate, phosphorus oxyacid, etc., to achieve the effect of improving the product's easy agglomeration, regular shape, and improved filtration performance

Active Publication Date: 2014-02-12
WUHAN INSTITUTE OF TECHNOLOGY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In recent years, the isothermal crystallization process of industrial monoammonium phosphate has also been studied in China, but most of them are limited to isothermal conditions.

Method used

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  • Method for crystallizing large-grained industrial ammonium dihydrogen phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] 1. Wet process phosphoric acid pretreatment

[0024] Take wet-process phosphoric acid and place it in a three-necked flask, add potassium carbonate and phosphate rock powder, where in molar ratio, wet-process phosphoric acid: potassium carbonate: phosphate rock powder=1:1.2:1.5, cover the bottle stopper, and place in a constant temperature water bath , the reaction temperature is 90°C, the stirring speed is 200r / min, the reaction time is 3h, and filtered; the filtrate is placed in a reaction vessel, and barium carbonate is added, wherein in terms of molar ratio, wet-process phosphoric acid: barium carbonate=1:1.1, Cover the bottle with a stopper, place it in a constant temperature water bath at 50°C, control the stirring speed to 200r / min, react with suction for 60min, and filter with suction. The filtrate is the pretreatment solution of wet-process phosphoric acid.

[0025] 2. Preparation of neutralizing solution

[0026] Weigh a certain amount of wet-process phosphor...

Embodiment 2

[0030] The preparation of wet-process phosphoric acid pretreatment and neutralizing liquid is as described in Example 1, and the density of neutralizing liquid of the present invention is concentrated to 1.36g / cm 3 , the concentrated solution was cooled and crystallized, and the temperature was lowered to 44°C under the conditions of a rotation speed of 270r / min and a temperature drop gradient of 0.1°C / min. Obtain 68.80 g of industrial grade monoammonium phosphate, with a purity of 98.24%. The product is a white crystal that is more uniform than industrial products, and the particle size distribution is too wide.

Embodiment 3

[0032] The preparation of wet-process phosphoric acid pretreatment and neutralizing liquid is as described in Example 1, and the density of neutralizing liquid of the present invention is concentrated to 1.37g / cm 3 , the concentrated solution was cooled and crystallized, and the temperature was lowered to 43°C under the conditions of a rotation speed of 280rmp and a temperature drop gradient of 0.5°C / min. Obtain 81.19g of industrial grade monoammonium phosphate with a purity of 98.53%. The product is a relatively uniform white crystal with an average surface area particle size of 1119.241 μm, a volume average particle size of 998.051 μm, and an average particle size of 1086.919 μm.

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Abstract

The invention relates to a method for crystallizing large-grained industrial ammonium dihydrogen phosphate. The method comprises the following steps of neutralizing a wet-process phosphoric acid pretreatment solution and ammonia gas which serve as starting raw materials twice to obtain a neutralization solution, concentrating the neutralization solution to obtain a required concentrated solution, crystallizing the obtained concentrated solution under a cooling gradient of 0.1 to 0.6 DEG C per minute, and filtering the crystallized solution to obtain grained industrial ammonium dihydrogen phosphate in a stable crystal form. Compared with the prior art, the method mainly has the advantages that the technical problems of small crystallization grain sizes, non-uniform graini size distribution, irregular shapes and the like of the industrial ammonium dihydrogen phosphate are solved, and the filtering performance and agglomeration rate of a product are improved; based on P2O5 in a wet-process phosphoric acid, the yield of the product is 3 to 5 percent higher than that of conventional industrial production yield, and the purity of the industrial ammonium dihydrogen phosphate is more than 98 percent; compared with a conventional industrial production method, the method has the advantages that the industrial ammonium dihydrogen phosphate has large grain sizes and regular shapes, and is uniform in grain size distribution, and an average grain size is 1,285mu m.

Description

technical field [0001] The invention relates to an industrial crystallization process, namely a crystallization method for producing large-grain industrial-grade monoammonium phosphate from wet-process phosphoric acid. Background technique [0002] With the development of science and economy and the progress of human society, people's awareness of environmental protection is increasing, and the requirements for fire extinguishing agent technology and environmental protection are also further improved. Because halon fire extinguishing agent is destructive to the ozone in the atmosphere and is not conducive to the sustainable development of the environment, it has been banned internationally. However, industrial grade monoammonium phosphate is a good phosphorus flame retardant and has no damage to the ozone in the atmosphere. , can be used as one of the preferred materials to replace halon, so the demand for industrial grade monoammonium phosphate fire extinguishing agent will...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/28
Inventor 丁一刚李青龙秉文吴元欣何俊陈遵逵李鹏涛
Owner WUHAN INSTITUTE OF TECHNOLOGY
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