Method for preparing calcium sulfate crystal whisker from many kinds of industrial waste residue gypsum serving as raw materials

A technology of calcium sulfate whiskers and industrial waste residues, which is applied to the growth of polycrystalline materials, chemical instruments and methods, and single crystal growth, can solve the problems of wasting manpower and material resources, slow hydration speed, and insoluble in water. The effect of short production cycle, moderate equipment requirements and easy process

Inactive Publication Date: 2011-10-12
SHANGHAI UNIV
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  • Abstract
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  • Claims
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Problems solved by technology

The main component of the newly discharged fluorine gypsum is anhydrous calcium sulfate, which is insoluble in water and has a very slow hydration rate, so it cannot be used directly as a cementitious

Method used

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  • Method for preparing calcium sulfate crystal whisker from many kinds of industrial waste residue gypsum serving as raw materials
  • Method for preparing calcium sulfate crystal whisker from many kinds of industrial waste residue gypsum serving as raw materials
  • Method for preparing calcium sulfate crystal whisker from many kinds of industrial waste residue gypsum serving as raw materials

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Embodiment 1

[0020] Example 1: Combine phosphogypsum, desulfurized gypsum and fluorine gypsum in any mass ratio and then mix them with nitric acid solution at a mass ratio of 8:100. The concentration of nitric acid is 2.5mol / L. After heating up to calcium sulfate gradually dissolved, filter while hot Adjust the solid-to-liquid ratio of calcium sulfate and water in the filtrate to be 1:10, add wt.5% magnesium chloride to make slurry as structure-directing agent, adjust slurry pH value to be 3, slurry is transferred in the reactor, control The reaction temperature is 140°C, and the reaction time is 2h; after the reaction is completed, cool to room temperature, filter, wash, and control the drying time to 120min at 80°C to obtain high-quality calcium sulfate whiskers. Calcium sulfate hemihydrate (CaSO 4 ·(1 / 2)H 2 O), the scanning electron microscope shows that the average diameter of the whiskers is 1 μm, the average length is 120 μm, and the whiteness of the whiskers measured by the whitene...

Embodiment 2

[0021] Embodiment 2: This embodiment is basically the same as Embodiment 1, the difference is that the reaction time is 8h. Calibrated as anhydrous calcium sulfate (CaSO 4 ), the scanning electron microscope shows that the average diameter of the whiskers is 0.8 μm, the average length is 100 μm, and the whiteness of the whiskers measured by the whiteness meter is 95.6%.

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Abstract

The invention relates to a method for preparing a high-quality calcium sulfate crystal whisker, which comprises the following steps of: purifying industrial waste residue gypsum serving as a raw material by utilizing the characteristic of the obvious change of the solubility of calcium sulfate in specific acid solution with temperature, adjusting the solid-to-liquid ratio and pH value of purified filter liquor, and synthesizing the high-purity and high-whiteness calcium sulfate crystal whisker in a hydrothermal mode under the action of a structural guiding agent. In a process for preparing the calcium sulfate crystal whisker from many kinds of industrial waste residue gypsum, the bottleneck problem of the large-scale industrial utilization of complex varieties of waste residue gypsum impurities is solved fundamentally, and the aims of saving energy, reducing emission and recycling waste materials are fulfilled, and the method has a bright application and market prospect.

Description

technical field [0001] The invention relates to a method for preparing calcium sulfate whiskers by using industrial waste gypsum, and belongs to the technical fields of resource recycling and preparation of inorganic fillers. Background technique [0002] Industrial waste gypsum is an industrial by-product produced by chemical reactions in industrial production, with calcium sulfate as the main component. Phosphogypsum is produced in the production process of phosphorus chemical fertilizers and compound fertilizers and various additives, desulfurized gypsum produced by lime wet desulfurization in large coal-fired facilities, citric acid gypsum produced in the process of fermentation of citric acid, decomposed with sulfuric acid Fluorogypsum produced in the process of producing hydrogen fluoride from fluorite and salt gypsum produced in various chemical productions are the main types of waste residue. In 2010, the total discharge of various types of industrial waste gypsum i...

Claims

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Application Information

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IPC IPC(8): C30B29/62C30B29/46C30B7/10
Inventor 钱明杨文文冯欣时雯汤庆利王钢领杨廷廷施利毅
Owner SHANGHAI UNIV
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