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A kind of method for preparing calcium sulfate dihydrate whisker from phosphogypsum

A technology of calcium sulfate dihydrate and phosphogypsum, applied in chemical instruments and methods, single crystal growth, crystal growth and other directions, can solve the problem that impurities are difficult to be fully removed, the yield and purity of calcium sulfate whiskers are low, and it is difficult to realize industrial production. and other problems, to achieve good economic and environmental benefits, easy to put into industrial production, and reduce the effect of the impact rate.

Inactive Publication Date: 2016-08-17
GUIZHOU KAILIN GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The above methods have their own shortcomings, mainly in the low purity of calcium sulfate whisker product yield, low whiteness, small aspect ratio, and complicated preparation process; specifically reflected in: phosphogypsum is directly used for calcium sulfate without pretreatment The preparation of whiskers or the preparation of calcium sulfate whiskers after pretreatment, but whether it is phosphogypsum without pretreatment or after pretreatment, its impurities are difficult to be fully removed, so that many of the phosphogypsum contained in it Various impurities will affect the quality of whiskers, such as magnesium delays the transformation of gypsum crystal form, iron will widen the crystal, aluminum affects the length and width of calcium sulfate dihydrate crystals, and excessive sulfate radicals will cause strong agglomeration of crystals, etc. At the same time, the purity and whiteness of calcium sulfate whisker products will also be low due to impurities
[0010] Among the various pretreatment methods for preparing calcium sulfate whiskers from phosphogypsum, the whiskers prepared by ball milling have rough surface and low length-to-diameter ratio; the screening conditions are difficult to control, high energy consumption, large investment, and difficult to realize industrial production ;Water washing consumes a lot of water, and sewage treatment is difficult; the phosphogypsum produced by wet-process phosphoric acid has strong acidity, and the cost of neutralization with lime is high. The yield of leaching and removing impurities is low, and the energy consumption per unit mass of calcium sulfate whisker is large

Method used

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  • A kind of method for preparing calcium sulfate dihydrate whisker from phosphogypsum
  • A kind of method for preparing calcium sulfate dihydrate whisker from phosphogypsum

Examples

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Embodiment 1

[0037] A method for preparing calcium sulfate dihydrate whiskers from phosphogypsum, comprising the following steps:

[0038] (1) Preparation of impurity-removing calcium sulfate dihydrate: Preheat 500g of 5wt% hydrochloric acid solution to 90°C, add phosphogypsum at a solid-to-liquid ratio of 1:30, stir and react for 15min at a speed of 200r / min, and heat Once filtered, the filter cake is reused. The filtrate is cooled and crystallized at room temperature. After the crystallization is completed, it is filtered twice. The filter cake is calcium sulfate dihydrate after removal of impurities, and the filtrate is reused to dissolve phosphogypsum.

[0039] (2) Whisker preparation: take 50g of calcium sulfate dihydrate after removing impurities, add 5wt% dilute hydrochloric acid at a solid-to-liquid ratio of 1:30, stir at a speed of 150r / min, and heat it in a water bath to 90°C to dissolve it completely , add 0.025g sodium lauryl sulfate, continue to stir until dissolved, place in ...

Embodiment 2

[0044] A method for preparing calcium sulfate dihydrate whiskers from phosphogypsum, comprising the following steps:

[0045] (1) Preparation of impurity-removing calcium sulfate dihydrate: preheat 1000g of 8wt% hydrochloric acid solution to 85°C, add phosphogypsum at a solid-to-liquid ratio of 1:25, stir and react for 10min at a speed of 250r / min, and heat Once filtered, the filter cake is reused. The filtrate is cooled and crystallized at room temperature. After the crystallization is completed, it is filtered twice. The filter cake is calcium sulfate dihydrate after removal of impurities, and the filtrate is reused to dissolve phosphogypsum.

[0046] (2) Whisker preparation: take 100g of calcium sulfate dihydrate after removing impurities, add 8wt% dilute hydrochloric acid according to the ratio of solid to liquid ratio of 1:25, stir at a speed of 200r / min, and heat it in a water bath to 85°C to dissolve it completely , add 0.05g sodium lauryl sulfate, continue to stir unti...

Embodiment 3

[0051] A method for preparing calcium sulfate dihydrate whiskers from phosphogypsum, comprising the following steps:

[0052] (1) Preparation of impurity-removing calcium sulfate dihydrate: After preheating 1000g of 10wt% hydrochloric acid solution to 80°C, add phosphogypsum at a solid-to-liquid ratio of 1:20, stir and react for 8min at a speed of 300r / min, and Filtrate once, and reuse the filter cake. The filtrate is cooled and crystallized at room temperature. After the crystallization is completed, filter twice. The filter cake is calcium sulfate dihydrate after impurity removal.

[0053] (2) Whisker preparation: take 100g of calcium sulfate dihydrate after removing impurities, add 10wt% dilute hydrochloric acid according to the ratio of solid-to-liquid ratio of 1:20, stir at a speed of 250r / min, and heat it in a water bath to 80°C to dissolve it completely , add 0.05g sodium lauryl sulfate, continue to stir until dissolved, place at room temperature to cool and crystallize...

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Abstract

The present invention relates to the technical field of chemical raw material preparation, and particularly to a method for preparing calcium sulfate dihydrate crystal whisker from phosphorus gypsum. The method comprises the following steps: preparing calcium sulfate dihydrate without impurities, preparing a crystal whisker, washing, and drying to obtain the calcium sulfate dihydrate crystal whisker. By preheating hydrochloric acid and matching the hydrochloric acid with phosphorus gypsum at a certain ratio at a constant temperature, the reaction can proceed and the materials is not wasted, the impurities contained in the phosphorus gypsum can be properly removed maximatily, the impact rate of impurities on the generation of calcium sulfate dihydrate crystal whisker is decreased, the content of calcium sulfate component is increased, the production rate of calcium sulfate dihydrate crystal whisker is improved and the production costs of calcium sulfate dihydrate crystal whisker prepared by comprehensively utilizing phosphorus gypsum are reduced.

Description

technical field [0001] The invention relates to the technical field of chemical raw material preparation, in particular to a method for preparing calcium sulfate dihydrate whiskers from phosphogypsum. Background technique [0002] Phosphogypsum is an accompanying substance in the production process of wet-process phosphoric acid, and its main component is calcium sulfate dihydrate. At present, natural stacking is the main treatment method for phosphogypsum. The stock of phosphogypsum in my country is more than 300 million tons, and it is increasing at a scale of 40-50 million tons per year. Stacking, fluoride, free phosphoric acid, P contained in phosphogypsum 2 o 5 , phosphate and other impurities will cause serious harm to the ecological environment; at the same time, the application of phosphogypsum in the fields of building materials, soil amendments and road construction also has problems such as high energy consumption, secondary pollution, and low added value of prod...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B29/14C30B29/62C30B7/08
Inventor 张意廖吉星熊陈杰彭宝林朱飞武
Owner GUIZHOU KAILIN GRP CO LTD
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