A method for reducing sulfate radical content in dihydrate dilute phosphoric acid

A technology of sulfate radical and dilute phosphoric acid, applied in the field of phosphoric acid, can solve the problems of long desulfurization time, high phosphorus residue in filter residues, difficult to handle, etc., and achieve the effect of good desulfurization effect, short desulfurization reaction time and fast reaction.

Active Publication Date: 2016-01-06
WENGFU (GRP) CO LTD
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  • Claims
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Problems solved by technology

Although the method of adding phosphate rock to dilute phosphoric acid can reduce the content of sulfate radicals in dilute phosphoric acid, there are disadvantages such as long desulfurization time, phosphoric acid needs to be settled and filtered after desulfurization, sedimentation residue is difficult to handle, and residual phosphorus in filter residue is high.

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  • A method for reducing sulfate radical content in dihydrate dilute phosphoric acid

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Embodiment 1

[0019] 10 tons of wet-process phosphoric acid extraction slurry that has completed the phosphoric acid extraction reaction obtained by the dihydric wet-process phosphoric acid process has a liquid phase mass of 7.1t, and a liquid phase sulfate radical mass percentage of 3.0%. Add 395 kg of desulfurizer (fertilizer grade calcium hydrogen phosphate) with a phosphorus content of 13% and a calcium content of 22%, that is, the mass ratio of the calcium content in the desulfurizer to the sulfate radical in the slurry phase of the wet-process phosphoric acid extraction material is about 0.41:1 , the desulfurizer is added to the phosphoric acid extraction slurry, mixed and stirred at 75°C for 20 minutes, and then the mixed slurry is sent to the filter of the phosphoric acid extraction device for filtration, and dilute phosphoric acid is obtained by filtration, and the mass percentage of sulfate radicals in dilute phosphoric acid is 0.6 %.

Embodiment 2

[0021] 8 tons of wet-process phosphoric acid extraction slurry that has completed the phosphoric acid extraction reaction obtained by the dihydric wet-process phosphoric acid process, its liquid phase quality is 5.5t, and the mass percentage content of liquid phase sulfate is 4.5%, in this phosphoric acid extraction slurry Add 310kg of desulfurizer (fertilizer grade calcium hydrogen phosphate) with a phosphorus content of 10% and a calcium content of 28%, that is, the mass ratio of the calcium content in the desulfurizer to the sulfate radical in the slurry phase of the wet-process phosphoric acid extraction material is about 0.35:1 , the desulfurizer is added to the phosphoric acid extraction slurry, mixed and stirred at 80°C for 5 minutes, and then the mixed slurry is sent to the filter of the phosphoric acid extraction device for filtration, and the diluted phosphoric acid is obtained by filtration. The mass percentage of sulfate radicals in the diluted phosphoric acid is 1.1...

Embodiment 3

[0023] 15 tons of wet-process phosphoric acid extraction slurry obtained by the dihydric wet-process phosphoric acid process has completed the phosphoric acid extraction reaction, its liquid phase quality is 11t, and the liquid phase sulfate radical mass percentage is 1.8%. In this phosphoric acid extraction slurry Add 550kg of desulfurizer (fertilizer grade calcium hydrogen phosphate) with a phosphorus content of 17% and a calcium content of 18%, that is, the mass ratio of the calcium content in the desulfurizer to the sulfate radical in the slurry phase of the wet-process phosphoric acid extraction material is about 0.50:1, After the desulfurizer is added to the phosphoric acid extraction slurry, mix and stir at 60°C for 30 minutes, then send the mixed slurry to the filter of the phosphoric acid extraction device for filtration, and filter to obtain dilute phosphoric acid. The mass percentage of sulfate radicals in dilute phosphoric acid is 0.2% .

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Abstract

The invention discloses a method for reducing the content of sulfate radicals in dihydric dilute phosphoric acid, which is characterized in that a desulfurizer is added to wet-process phosphoric acid extraction slurry, mixed and stirred, and mixed and reacted at 60-80°C for 5-30 minutes. Then the mixed slurry is sent to the filter of the phosphoric acid extraction device for filtration, and the diluted phosphoric acid with a sulfate mass percentage content of less than 1.2% is obtained by filtration; The mass ratio of sulfate radicals in the medium is 0.35-0.50:1. The present invention solves the problem of high sulfate content in the dilute phosphoric acid of the dihydrate method, and is beneficial to the use of the dihydrate method phosphoric acid in the production of high-nutrient ammonium phosphate fertilizer, feed grade phosphate, industrial grade ammonium phosphate and phosphoric acid purification products. Simple, short desulfurization reaction time, good desulfurization effect and low desulfurization cost.

Description

technical field [0001] The invention relates to the field of phosphoric acid, in particular to a method for reducing the content of sulfate radicals in dilute phosphoric acid obtained from a dihydric wet-process phosphoric acid process. Background technique [0002] The production of wet-process phosphoric acid in my country mainly adopts the process of dihydrate wet-process phosphoric acid. In order to obtain dihydrate gypsum crystals with coarse crystals and easy to filter, sulfuric acid must be in excess. Generally, the excess of sulfuric acid is about 5%. As the impurity content of phosphate rock increases, the amount of sulfuric acid needs to be properly excessive. Therefore, there is a certain amount of sulfate in the obtained phosphoric acid, and the sulfate content is as high as about 2.5% to 4.5%. The existence of sulfate affects the quality of phosphoric acid deep-processing products, reducing the content of sulfate in dihydrate phosphoric acid, which is conducive ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/237
Inventor 刘旭解田胡宏杨丽萍石玲元杨俊
Owner WENGFU (GRP) CO LTD
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