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Production method for by-product alpha-hemihydrate gypsum of wet-process phosphoric acid

A technology of hemihydrate gypsum and wet-process phosphoric acid, which is applied in chemical instruments and methods, nitric acid, phosphorus compounds, etc., can solve the problems of uncontrollable length-to-diameter ratio of α hemihydrate gypsum, application restrictions, and restrictions on high-end applications, etc., to achieve industrialization Continuous large-scale production, improve utilization rate, and solve difficult-to-handle effects

Active Publication Date: 2016-01-20
贵州正磷科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method cannot control the aspect ratio of α hemihydrate gypsum under the condition of dihydrate-hemihydrate crystallization. Although α hemihydrate gypsum products can be produced, the strength of α hemihydrate gypsum products is low, and the application of the products is limited, and the phosphorus in the products content is still high
[0005] To sum up, the problems existing in the prior art are: firstly, wastes such as acid-insoluble matter still need to be discharged; secondly, the by-product gypsum is dihydrate, which needs subsequent processing to become α hemihydrate gypsum or β hemihydrate gypsum, etc. The third is that the obtained α hemihydrate gypsum product has low strength and high phosphorus content, which limits its high-end application

Method used

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  • Production method for by-product alpha-hemihydrate gypsum of wet-process phosphoric acid
  • Production method for by-product alpha-hemihydrate gypsum of wet-process phosphoric acid
  • Production method for by-product alpha-hemihydrate gypsum of wet-process phosphoric acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] Embodiment 1. The phosphate rock is collected in Kailin, Guizhou; the content of phosphorus pentoxide in the phosphate rock is about 32%.

[0054] A kind of production method of wet-process phosphoric acid by-product α hemihydrate gypsum, the steps are as follows:

[0055] (1) First, phosphate rock powder and dilute sulfuric acid with a mass concentration of 20% are added to the extraction tank at a solid-to-liquid mass ratio of 1:4, the fineness of the phosphate rock powder is 100 mesh, and the content of phosphorus pentoxide in the phosphate rock is 32 %, under continuous stirring, the temperature of the extraction tank was controlled at 80°C for an extraction reaction for 30 minutes to obtain a mixed slurry A;

[0056] (2) Separate 1 / 6 of the volume of the mixed slurry A obtained in step (1) through a filter for solid-liquid separation to obtain clear liquid B and solid C, and the separated clear liquid B is sent to the acid storage as finished phosphoric acid , the...

Embodiment 2

[0062] Embodiment 2, the phosphate rock is collected in Lufa, Guizhou; the content of phosphorus pentoxide in the phosphate rock is 27%.

[0063] A kind of production method of wet-process phosphoric acid by-product α hemihydrate gypsum, the steps are as follows:

[0064] (1) Firstly, phosphate rock powder and dilute sulfuric acid with a mass concentration of 30% are added to the extraction tank at a solid-to-liquid mass ratio of 1:3. The fineness of the phosphate rock powder is 100 mesh, and the content of phosphorus pentoxide in the phosphate rock is 27%. , under continuous stirring, control the temperature of the extraction tank at 70°C for 50 minutes of extraction reaction to obtain a mixed slurry A;

[0065] (2) Separate 2 / 3 of the volume of the mixed slurry A obtained in step (1) through a filter for solid-liquid separation to obtain clear liquid B and solid C, and the separated clear liquid B is sent to the acid storage as finished phosphoric acid , the solid C is tran...

Embodiment 3

[0072] With the production method of a kind of wet-process phosphoric acid by-product α hemihydrate gypsum described in embodiment 1, the difference is that the crystal modifier component and content of use are different, as shown in table 1:

[0073] Table 1 crystal transformation agent component, content and the performance that obtains product

[0074]

[0075] It can be known from the above table that the present invention can produce gypsum powder with an aspect ratio of <10 or less. It can be seen that the shape of the α hemihydrate gypsum prepared by the present invention can be controlled, and α hemihydrate gypsum powders with different aspect ratios can be prepared by adjusting the formula of the crystal modifier to meet different market demands.

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Abstract

The invention discloses a production method for a by-product alpha-hemihydrate gypsum of wet-process phosphoric acid. The method comprises the following steps: adding ground phosphate rock and a part of dilute sulfuric acid into an extraction tank, carrying out an extraction reaction, separating a clear liquid from obtained mixed slurry, using the clear liquid as a finished product phosphoric acid, sending the phosphoric acid into an acid pool, and transferring a separated solid and residual mixed slurry into a crystal transformation tank together; adding sulfuric acid and a crystal transformation agent into the crystal transformation tank, carrying out a crystal transformation reaction at 60 to 130 DEG C for 1.5 to 7.5 h, subjecting obtained mixed acid slurry to solid-liquid separation, and subjecting the obtained solid to drying so as to obtain gypsum powder or adding water into the solid without drying so as to prepare gypsum products like gypsum boards, gypsum building blocks and gypsum members. The production method provided by the invention improves traditional technology and the prior art, eliminates discharge of phosphogypsum and acid non-soluble substances, reduces the content of phosphorus in gypsum, improves the utilization rate of phosphorus, makes full use of dilution heat of concentrated sulfuric acid and realizes energy saving and emission reduction.

Description

technical field [0001] The invention relates to a production method of wet-process phosphoric acid, in particular to a production method of wet-process phosphoric acid by-product α hemihydrate gypsum. Background technique [0002] The so-called "wet-process phosphoric acid" actually refers to the sulfuric acid wet-process phosphoric acid, that is, the phosphoric acid produced by decomposing phosphate rock with sulfuric acid. More than 80% of phosphoric acid in my country is produced by the wet process phosphoric acid dihydrate process. The dihydric process has the characteristics of simple process, mature technology and strong adaptability to ore types. It is especially suitable for medium and low-grade ores, and occupies a dominant position in the production of wet-process phosphoric acid. However, there are still some insurmountable defects in the dihydric process. The by-product phosphogypsum is subject to many restrictions because of its high phosphorus content. coagul...

Claims

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Application Information

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IPC IPC(8): C01B21/38C01F11/46
CPCC01F11/46C01B25/2204C01B25/2295C01B25/226C01F11/466
Inventor 胡兆平陈宏坤姚华龙刘永秀李成志张西兴
Owner 贵州正磷科技有限公司
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