Method for preparing alpha semi-hydrated gypsum from dihydrate gypsum

A technology of hemihydrate gypsum and dihydrate gypsum, which is applied in the field of preparation of α hemihydrate gypsum, which can solve the problems of unstrict control of dihydrate-semihydrate crystallization conditions, unreasonable distribution of aspect ratio of α hemihydrate gypsum, and α hemihydrate gypsum. Low gypsum strength and other problems, to achieve the effect of appropriate aspect ratio distribution range, good environmental and economic benefits, and concentrated aspect ratio distribution range

Active Publication Date: 2015-12-23
贵州正磷科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The dihydrate-hemihydrate crystallization conditions of this process are not strictly controlled, and the aspect ratio distribution of the obtained α hemihydrate gypsum is unreasonable. Although the α hemihydrate gypsum product can be produced, the strength of the α hemihydrate gypsum product is low, and the application of the product is limited. restrictions, and the phosphorus content in the product is still high

Method used

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  • Method for preparing alpha semi-hydrated gypsum from dihydrate gypsum
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  • Method for preparing alpha semi-hydrated gypsum from dihydrate gypsum

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Embodiment 1

[0045] Raw material 1: Phosphogypsum, collection location: Kingenta Ecological Engineering Group Co., Ltd.

[0046] Raw material 2: Phosphoric acid, 60%, commercially available

[0047] Raw material 3: sulfuric acid, 97%, commercially available

[0048] Raw material 4: sodium citrate, commercially available

[0049] Raw material 5: EDTA, commercially available

[0050] Raw material 6: iron sulfate, commercially available

[0051] Preparation:

[0052] (1) Add dihydrate gypsum into the strong acid aqueous solution containing sulfuric acid and phosphoric acid mixed acid according to the solid-to-liquid ratio of 1:2.5, and mix evenly to obtain mixed slurry A, wherein the mass of sulfuric acid is expressed as H 2 SO 4 The mass fraction of mixed acid is 9.00%, and the mass of phosphoric acid is represented by P 2 o 5 The mass fraction of the mixed acid is 20.00%, and the mass fraction of the added water is 34.79% of the mixed acid aqueous solution.

[0053] (2) Add a crysta...

Embodiment 2

[0061] Raw material 1: desulfurized gypsum, collection location: Linyi Power Plant

[0062] Raw material 2: Phosphoric acid, 60%, commercially available

[0063] Raw material 3: sulfuric acid, 97%, commercially available

[0064] Raw material 4: sodium dodecylbenzenesulfonate, commercially available

[0065] Raw material 5: EDTA, commercially available

[0066] Raw material 6: aluminum sulfate, commercially available

[0067] Preparation:

[0068] (1) Add dihydrate gypsum into the strong acidic aqueous solution containing sulfuric acid and phosphoric acid mixed acid according to the ratio of solid-to-liquid ratio of 1:3, and mix evenly to prepare mixed slurry A, wherein the mass of sulfuric acid is expressed as H 2 SO 4 The mass fraction of mixed acid is 10%, and the mass of phosphoric acid is expressed as P 2 o 5 The mass fraction of the mixed acid is 22%, and the mass fraction of the water is 31.27% of the mixed acid aqueous solution.

[0069] (2) Add a crystal-trans...

Embodiment 3

[0077] Raw material 1: Phosphogypsum, collection location: Kingenta Ecological Engineering Group Co., Ltd.

[0078] Raw material 2: Phosphoric acid, 60%, commercially available

[0079] Raw material 3: sulfuric acid, 97%, commercially available

[0080] Raw material 4: sodium glutarate, commercially available

[0081] Raw material 5: EDTA, commercially available

[0082] Raw material 6: aluminum sulfate, commercially available

[0083] Preparation:

[0084] (1) Add dihydrate gypsum into the strong acidic aqueous solution containing sulfuric acid and phosphoric acid mixed acid according to the ratio of solid to liquid ratio of 1:4, and mix evenly to prepare mixed slurry A, wherein the mass of sulfuric acid is expressed as H 2 SO 4 The mass fraction of mixed acid is 14%, and the mass of phosphoric acid is represented by P 2 o 5 The mass fraction of the mixed acid is 25%, and the mass fraction of the water is 20.99% of the mixed acid aqueous solution.

[0085] (2) Add a c...

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Abstract

The invention relates to a method for preparing alpha semi-hydrated gypsum from dihydrate gypsum. The method comprises the following steps: adding dihydrate gypsum and a crystal modifier into a mixed acid water solution containing sulfur acid and phosphoric acid to carry out crystal transformation, carrying out solid-liquid separation, returning a part of liquid phase into a crystal transformation tank for crystal transformation, and conveying another part of liquid phase to an acidolysis tank for use, wherein the acidolysis tank is used for preparing phosphoric acid by decomposing phosphorite by virtue of sulfuric acid; adding washing water to wash a solid phase, and introducing the washing water into the liquid phase for use. The washed solid phase can be prepared into alpha semi-hydrated gypsum powder through drying and can be prepared into gypsum products such as gypsum boards, gypsum blocks, gypsum components and the like by directly adding water without drying. According to the method, the alpha semi-hydrated gypsum is prepared in the mixed acid water solution containing sulfur acid and phosphoric acid, procedures including desulfuration, removal of impurity and the like on raw gypsum can be omitted, furthermore, mixed acid can be recycled, and the obtained alpha semi-hydrated gypsum product is high in strength and stable in quality.

Description

technical field [0001] The invention relates to the preparation of alpha hemihydrate gypsum, in particular to a method for preparing alpha hemihydrate gypsum from dihydrate gypsum. Background technique [0002] my country is rich in natural gypsum mineral resources, with a total reserve of nearly 60 billion tons, ranking first in the world. It is also a major manufacturer of chemical gypsum. A large amount of chemical gypsum is produced every year. Chemical gypsum generally refers to by-products in various industrial productions. , is industrial waste, which contains a certain amount of dihydrate gypsum and more impurities. When calling these gypsums, it is customary to add the name of the original main product type or gypsum source type in front of it, such as phosphogypsum, fluorogypsum, and flue gas desulfurization. Gypsum, Glauber's salt gypsum, etc. Among them, nearly 20 million tons of phosphogypsum alone are produced every year, and the accumulation of phosphogypsum in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B11/02
Inventor 刘永秀李成志王伯通刘伟胡兆平滕美丽
Owner 贵州正磷科技有限公司
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