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Technique for preparing alpha-semi-hydrated gypsum from chemical gypsum

A technology for chemical gypsum and hemihydrate gypsum is applied in the field of chemical gypsum to prepare α-hemihydrate gypsum, which can solve problems such as product performance decline.

Inactive Publication Date: 2008-09-10
辽宁东大粉体工程技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Drying temperature and time are very important. If the temperature is too high or the time is too long, the hemihydrate gypsum will be dehydrated to form anhydrous gypsum. If the temperature is too low or the time is too short, the hemihydrate gypsum will generate secondary dihydrate gypsum, resulting in a decline in product performance.

Method used

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  • Technique for preparing alpha-semi-hydrated gypsum from chemical gypsum

Examples

Experimental program
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Effect test

example 1

[0019] Transport the chemical gypsum powder to the slurry mixing tank to prepare gypsum slurry with a slurry concentration of 50wt%, and at the same time inject a crystallization agent into the mixing tank, the total concentration of the crystallization agent is 4wt% of the total concentration of the slurry, and the composition is: Al 2 (SO 4 ) 3 1wt%, CaCl 2 1wt%, KCl 1wt%, MgCl 2 1wt%, and at the same time add soapy water with a concentration of 0.1wt% of the total concentration of the slurry, and at the same time feed hot water for stirring, so that the crystallization agent and surfactant are fully contacted with the material. The stirred slurry is transported to the 1# preliminary reaction kettle through the slurry pump, the pressure is 1.3MPa, the reaction temperature is 220°C, the stirring speed is 100 rpm, the dynamic residence time of the material is 5 minutes, and hot air is introduced at the same time Heating and heat preservation are carried out to make the d...

example 2

[0021] Transport the chemical gypsum to the slurry mixing tank to prepare gypsum slurry with a slurry concentration of 50wt%, and at the same time inject a crystallization agent into the mixing tank, the concentration of the crystallization agent is 0.1wt% of the total concentration of the slurry, and the composition is Al 2 (SO 4 ) 3, and at the same time add industrial pulp waste liquid, the concentration is 3wt% of the total concentration of the slurry, while feeding hot water for continuous stirring, so that the crystallization agent and surfactant are fully contacted with the material. The stirred slurry is input into 1# preliminary reactor, the pressure is 0.6MPa, the reaction temperature is 150°C, the stirring speed is 60 rpm, the dynamic residence time of the material is 25 minutes, and hot air is introduced at the same time for heating and heat preservation. The slurry is transported to the 2# deep reaction kettle through the pressure relief valve using the combined ...

example 3

[0023] Transport the chemical gypsum to the slurry mixing tank to prepare gypsum slurry with a slurry concentration of 75wt%, and inject a crystallization agent into the stirring tank at the same time, the concentration of the crystallization agent is 3wt% of the total concentration of the slurry, and the composition is: CaCl 2 , and add surfactant simultaneously to be 10wt% of the total concentration of slurry: 5wt% of soapy water, 5wt% of industrial paper pulp waste liquid, pass into hot water and stir continuously simultaneously, make crystallization agent and surfactant fully contact with material. Transfer the stirred slurry to 1# preliminary reaction kettle, the pressure is 0.4MPa, the reaction temperature is 100°C, the stirring speed is 40 rpm, the dynamic residence time of the material is 45 minutes, and hot air is introduced at the same time for heating and heat preservation . Through the pressure relief valve, the slurry is transported to the 2# deep reaction kettle ...

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Abstract

The invention relates to a process method used in the preparation of Alpha-semi-hydrated gypsum by chemical gypsum. The invention comprises the following process steps: chemical gypsum is prepared inside a slurry tank with the concentration ranging between 50 percent and 85 percent according to weight percentage; meanwhile, habit modifier and surface active agent are added in; the prepared slurry is fed in an initial reaction kettle to complete primary reaction with the reaction temperature ranging between 100 DEG C and 220 DEG C, the pressure ranging from 0.15MPa to 1.3MPa, the stirring speed kept between 20 revolutions / minute to 100 revolutions / minute and the dynamic residence time range varying between 5 minutes to 60 minutes; then, primary reaction material is fed to a severe reaction kettle to complete severe reaction with reaction temperature ranging between 100 DEG C and 220 DEG C, the pressure ranging from 0.14MPa to 1.29MPa, the stirring speed kept between 20 revolutions / minute to 100 revolutions / minute and the dynamic residence time range varying between 5 minutes to 60 minutes; finally, severe reaction material is fed to a pressure release tank through a relief valve and then is fed to a flash evaporation drier to be scattered, crushed and dried, thereby obtaining powder product. The entire technological process of the invention reduces the hydration time of gypsum, thereby realizing fast drying and continuous production; moreover, technological flow is reduced and the performance of high-strength gypsum powder is increased.

Description

technical field [0001] The invention relates to a process method for alpha-hemihydrate gypsum, in particular to a process method for preparing alpha-hemihydrate gypsum with chemical gypsum. Background technique [0002] Chemical gypsum, also known as industrial by-product gypsum, refers to the by-product or waste residue produced by chemical reactions in industrial production, with calcium sulfate (containing zero to two crystal waters) as the main component. Phosphate fertilizer chemical fertilizers, compound fertilizer production, coal-fired boiler flue gas limestone hair / lime wet desulfurization, fluorite decomposition with sulfuric acid to produce hydrogen fluoride, fermentation of citric acid will produce a large amount of chemical gypsum. Chemical gypsum is a very good renewable resource. Comprehensive utilization is not only conducive to resource protection, but also saves energy and resources, which is in line with my country's sustainable development strategy. [0...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B11/02
Inventor 张继宇林文强
Owner 辽宁东大粉体工程技术有限公司
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