Method for preparing calcium sulfate crystal whiskers from desulfurized gypsum under normal pressure

A calcium sulfate whisker and desulfurization gypsum technology, which is applied in the field of calcium sulfate whisker preparation and modification, can solve the problems of poor product quality, large calcium salt consumption, high raw material prices, etc., achieve good economic benefits, simple preparation process, increase The effect of corporate earnings

Active Publication Date: 2012-02-15
上海大学浙江嘉兴新兴产业研究院
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In 2009, the output of industrial by-product gypsum in my country was about 118 million tons, and the comprehensive utilization rate was only 38%, of which the output of desulfurized gypsum reached 43 million tons, and about 50% was not effectively utilized
[0006] The index of domestic calcium sulfate whiskers is dominated by the hydrothermal method, which has harsh reaction conditions and is difficult to promote to large-scale production
Using calcium salt, sulfate (or sulfuric acid) as raw material to prepare calcium sulfate whiskers needs to consume a large amount of calcium salt, sulfate (or sulfuric acid), which is not an economical method
The traditional calcium sulfate whisker production process has disadvantages such as high raw material prices, difficult wastewater treatment, high energy consumption, and poor product quality, which lead to expensive calcium sulfate whiskers and hinder the large-scale application of whiskers

Method used

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  • Method for preparing calcium sulfate crystal whiskers from desulfurized gypsum under normal pressure
  • Method for preparing calcium sulfate crystal whiskers from desulfurized gypsum under normal pressure
  • Method for preparing calcium sulfate crystal whiskers from desulfurized gypsum under normal pressure

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Embodiment 1

[0048] see Figure 1 to Figure 5 A method for preparing calcium sulfate whiskers from desulfurized gypsum under normal pressure provided in this embodiment comprises the following steps:

[0049] (1) Pickling: washing the desulfurized gypsum with excess inorganic acid dilute solution;

[0050] (2) Dissolving: mix the desulfurized gypsum after pickling with the acid solution, and keep stirring to dissolve the solid phase to obtain a mixed solution;

[0051] (3) crystal transformation: add a crystal transformation agent in the mixed solution, and carry out solid-liquid separation to remove solid-phase impurities to obtain a filtrate;

[0052] (4) Crystallization: the temperature of the filtrate is lowered, and after crystallization, the obtained filter cake is washed with water and dried to obtain calcium sulfate whiskers after solid-liquid separation.

[0053] Described step (1) specifically comprises the following steps:

[0054] (1.1) Prepare desulfurization gypsum;

[00...

Embodiment 2

[0077] The method for preparing calcium sulfate whiskers from desulfurized gypsum under normal pressure provided in this embodiment has the same basic steps as in Example 1, except that the following specific steps are different:

[0078] Crush the desulfurized gypsum from a coal-fired power plant, sieve it through an 80-mesh sieve, weigh 100.00 g of the crushed desulfurized gypsum, and then add it to a 1000 mL beaker at the same time as the 1000 mL 1mol / L nitric acid solution in advance, stir for 4 hours, remove Desulfurize the impurities in the gypsum raw material that react with the nitric acid solution to obtain a filter cake. The filter cake was then dried in a blast oven at 60° C. for 12 hours, and then crushed. Weigh 35.00 g of the above crushed filter cake, add it together with 500 mL, 2 mol / L nitric acid solution into a 1000 mL flask, then immerse more than two-thirds of the volume of the flask in a constant temperature oil bath at 100°C, And stirred for 1 hour, it w...

Embodiment 3

[0080] The method for preparing calcium sulfate whiskers under a kind of desulfurization gypsum normal pressure that present embodiment provides, its basic steps are identical with embodiment 2, and its difference is that its following specific steps are different:

[0081] Recycle 500mL of the filtrate in Example 2, add 35.01g of acid-washed desulfurized gypsum into a 1000mL flask at the same time, then immerse more than two-thirds of the volume of the flask in a 95°C constant temperature water bath, keep the temperature and stir for 1 hour , the solid phase was observed to dissolve, and when the solution was translucent, 3ml of silane coupling agent KH570 was added, kept at a constant temperature and stirred for 1 hour. A new round of filtrate was obtained, and then the filtrate was transferred to a 1000mL beaker and placed in a constant temperature water bath at 15°C for cooling and crystallization for 18 hours. Suction filtration is carried out after the crystallization is...

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Abstract

The invention discloses a method for preparing calcium sulfate crystal whiskers from desulfurized gypsum under normal pressure. The method comprises the following steps: 1) pickling; 2) dissolving; 3) rotating crystal; and 4) crystallizing, after crystallizing, carrying out solid-liquid separation, washing filter cake with water, and drying to obtain calcium sulfate crystal whiskers. The method disclosed by the invention has the advantages that: the preparation process is simple and is easy to achieve, and the production efficiency is high; higher-purity and higher-whiteness calcium sulfate crystal whiskers are prepared by adopting a normal-pressure recrystallization method, controlling related process conditions and utilizing the characteristic that the dissolubility of main component calcium sulfate dihydrate of desulfurized gypsum in specific solution changes obviously along with the temperature; obtained calcium sulfate crystal whisker product has regular morphology, low agglomeration and good dispersity; and in addition, inorganic acid solution used for recrystallization can be recycled, and inorganic acid solution is not consumed in the reaction process, thereby creating better economic benefit, environmental benefit and social benefit, reducing the burden of coal-fired power plant and increasing enterprise benefits.

Description

technical field [0001] The invention belongs to the technical field of preparation and modification of calcium sulfate whiskers, and in particular relates to a method for preparing calcium sulfate whiskers from desulfurized gypsum under normal pressure. Background technique [0002] Coal accounts for about 70% of all energy sources in my country, and a large amount of sulfur dioxide is produced during coal combustion. More than 80% of coal-fired power plants in my country use wet flue gas desulfurization technology (FGD), which produces a large amount of desulfurization The by-product is desulfurization gypsum. In 2009, the output of industrial by-product gypsum in my country was about 118 million tons, and the comprehensive utilization rate was only 38%. Among them, the output of desulfurized gypsum reached 43 million tons, and about 50% was not effectively utilized. The accumulated stock of industrial by-product gypsum has exceeded 300 million tons, the accumulated amount ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/46C30B29/62C30B7/08
Inventor 施利毅王钢领冯欣张迎杨文文时雯
Owner 上海大学浙江嘉兴新兴产业研究院
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