A method for preparing calcium sulfate hemihydrate whiskers from phosphogypsum

A technology of calcium sulfate hemihydrate and calcium sulfate dihydrate, applied in chemical instruments and methods, single crystal growth, crystal growth, etc., can solve problems such as serious equipment corrosion, large environmental impact, and long crystallization reaction time, and achieve crystallization It must have a large length-to-diameter ratio, reduce the impact on the environment and equipment, and save consumption

Active Publication Date: 2018-01-09
YUNNAN CHEM RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method requires a large amount of acid leaching, which seriously corrodes the equipment and takes a long time for the crystallization reaction. At the same time, the product obtained later has a low pH and requires a large amount of process water for washing, which has a great impact on the environment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment example 1

[0031] Get 200g of phosphogypsum produced by the phosphoric acid plant of Yunnan Tian'an Chemical Co., Ltd., the mineral chemical composition is:

[0032] main ingredient

Calcium sulfate dihydrate (%)

Silica (%)

BaiDu

analysis results

83.26

13.76

83.4

[0033] Add 600g of process water to make the concentration of phosphogypsum slurry 25%. After 1 roughing and 2 times of beneficiation, 156g of refined phosphogypsum with a grade of calcium sulfate dihydrate of 97.22% and a grade of silicon dioxide of 1.65% are obtained. Take the refined phosphogypsum Place it in a muffle furnace for calcination, the calcination temperature is 140°C, and the calcination time is 4h. Add 600g of process water to the calcined hemihydrate gypsum for stirring, washing and activation, and stir for 1h. The pH of the filtrate is 5.20. Take 50g of the phosphogypsum after washing and activation. Add 950g of process water to make a slurry with a solid mass concentr...

Embodiment example 2

[0036] Get 200g of phosphogypsum in the phosphogypsum storage yard of Yunnan Tian'an Chemical Co., Ltd., the mineral chemical composition is:

[0037] main ingredient

Calcium sulfate dihydrate (%)

Silica (%)

BaiDu

analysis results

73.46

26.33

73.4

[0038] Add 800g of process water to make the concentration of phosphogypsum slurry 20%. After 1 roughing and 2 times of beneficiation, 138g of refined phosphogypsum with a grade of calcium sulfate dihydrate of 97.82% and a grade of silicon dioxide of 1.35% are obtained. Take the refined phosphogypsum Place it in a muffle furnace for calcination, the calcination temperature is 160°C, and the calcination time is 6h. Add 800g of process water to the calcined hemihydrate gypsum for stirring, washing and activation, and stir for 1h. The pH of the filtrate is 5.80. Take 50g of the phosphogypsum after washing and activation. Add 1616g of process water to make a slurry with a solid mass concentrati...

Embodiment example 3

[0041] Get 200g of phosphogypsum in the phosphogypsum storage yard of Yunnan Tian'an Chemical Co., Ltd., the mineral chemical composition is:

[0042] main ingredient

Calcium sulfate dihydrate (%)

Silica (%)

BaiDu

analysis results

85.66

12.56

84.6

[0043] Add 600g of process water to make the concentration of phosphogypsum slurry 25%. After one roughing and one beneficiation, 138g of refined phosphogypsum with a grade of calcium sulfate dihydrate of 95.44% and a grade of silicon dioxide of 1.95% are obtained. Take the refined phosphogypsum Place it in a muffle furnace for calcination, the calcination temperature is 150°C, and the calcination time is 5h. Add 1000g of process water to the calcined hemihydrate gypsum for stirring, washing and activation, and stir for 1h. The pH of the filtrate is 6.20. Take 50g of the phosphogypsum after washing and activation. Add 950g of process water to make a slurry with a solid mass concentration of...

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Abstract

The invention relates to a method for preparing calcium sulfate hemihydrate whiskers from phosphogypsum. The phosphogypsum calcium sulfate dihydrate used in the present invention has a low grade and a wide range of sources. It does not need to undergo acid treatment to remove impurities. The grade of phosphogypsum can be improved by simple flotation desiliconization to remove a large amount of impurities. Preparation of calcium sulfate hemihydrate whiskers by thermal process. The process is simple, the sources of raw materials are wide, the production cost is low, and the environmental impact is small; the obtained calcium sulfate hemihydrate whiskers have the characteristics of high purity, large aspect ratio, uniform shape, stable crystal form, etc., and have good industrial application value.

Description

technical field [0001] The invention relates to a method for preparing calcium sulfate hemihydrate whiskers from phosphogypsum, and belongs to the technical field of comprehensive utilization of industrial solid waste resources. Background technique [0002] Phosphogypsum is a by-product of the wet process of phosphoric acid production. With the increasing demand for high-concentration phosphorus compound fertilizers at home and abroad, the development of the wet-process phosphoric acid industry has been promoted, and more phosphogypsum has also been produced. At the same time, with the increasing demand for phosphate rock resources in the phosphorus chemical industry and the continuous consumption of rich ore, the phosphoric acid plant has a great impact on the raw material P of phosphate rock. 2 o 5 The grade is getting lower and lower, the range of impurity content is getting higher and higher, and the grade of the phosphogypsum produced is also gradually decreasing. A...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B7/10C30B29/62C30B29/46
Inventor 朱鹏程王国栋罗鸣坤刘文彪
Owner YUNNAN CHEM RES INST
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