Method for preparing high-strength alpha-semi-hydrated gypsum from flue gas desulfurization gypsum

A technology of desulfurized gypsum and hemihydrate gypsum, applied in the field of material science, to achieve the effects of environmental protection, simple equipment, and simple preparation process

Inactive Publication Date: 2014-02-05
TIANJIN UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

This brings another environmental protection problem: a large number of by-products-flue gas desulfurization gypsum are produced in the process of flue gas desulfurization, that is, FGD gypsum becomes solid waste. However, flue gas desulfurization gypsum contains more than 95% calcium sulfate dihydrate, Its grade is comparable to natural gypsum

Method used

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  • Method for preparing high-strength alpha-semi-hydrated gypsum from flue gas desulfurization gypsum
  • Method for preparing high-strength alpha-semi-hydrated gypsum from flue gas desulfurization gypsum

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Embodiment Construction

[0015] specific implementation plan

[0016] The preparation of the high-strength short hexagonal columnar α-hemihydrate gypsum provided by the present invention mainly includes the following steps in its technical scheme:

[0017] 1) Preparation of desulfurization gypsum slurry: Mix flue gas desulfurization gypsum and water at a solid-to-liquid mass ratio of 1:4-10, stir for 1-2 hours to fully mix, and then heat up to 80-95°C.

[0018] 2) Adding a crystallization agent to prepare a mixed slurry: Add the mass ratio of flue gas desulfurization gypsum to crystallization agent to the desulfurization gypsum slurry obtained in step 1) at a mass ratio of 1:0.5 to 1.5. The crystallization agent is magnesium chloride hexahydrate and hexahydrate The mixture of magnesium sulfate, the mass ratio of magnesium chloride hexahydrate and magnesium sulfate hexahydrate is 1:0.1~0.2; continue to heat up to boiling (107~108°C), and reflux.

[0019] 3) Add crystallization habit modifier: accordin...

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Abstract

The invention belongs to the field of material science, and relates to a method for preparing high-strength alpha-semi-hydrated gypsum from flue gas desulfurization gypsum. The method comprises the following steps: 1) preparing desulfurization gypsum slurry: sufficiently mixing the flue gas desulfurization gypsum and water according to a solid-liquid mass ratio of 1: (4-10), and warming to 80-95 DEG.C; 2) adding a habit modifier to prepare mixed slurry: adding the habit modifier in the desulfurization gypsum slurry according to a condition that the mass ratio of the flue gas desulfurization gypsum to the habit modifier is 1: (0.5-1.5), wherein the habit modifier is a mixture of magnesium chloride hexahydrate and magnesium sulfate hexahydrate in a mass ratio of 1: (0.1-0.2), continuously warming to boil, and refluxing; 3) adding a crystal habit modifier: adding the crystal habit modifier in the mixed slurry obtained in the step 2) according to a condition that the mass ratio of the flue gas desulfurization gypsum to the crystal habit modifier is 1: (1%-5%); and 4) crystal transforming. The uniform short hexagonal prism alpha-semi-hydrated gypsum can be prepared by the method simple in process, the rupture strength reaches 14.4 MPa, and the compressive strength reaches 44.5 MPa.

Description

technical field [0001] The present invention belongs to the field of material science. The invention relates to a preparation method for producing high-strength α-type hemihydrate gypsum with flue gas desulfurization gypsum as the main raw material. Background technique [0002] In recent years, due to the requirements of environmental protection, flue gas desulfurization devices have been installed in major thermal power plants across the country. This brings another environmental protection problem: a large number of by-products-flue gas desulfurization gypsum are produced in the process of flue gas desulfurization, that is, FGD gypsum becomes solid waste. However, flue gas desulfurization gypsum contains more than 95% calcium sulfate dihydrate, Its grade is comparable to natural gypsum. It can be dehydrated into hemihydrate gypsum. Hemihydrate gypsum is divided into α-hemihydrate gypsum and β-hemihydrate gypsum. Compared with β-hemihydrate gypsum, α-hemihydrate gypsum...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B11/02
Inventor 孙淑清宋航王宗杰
Owner TIANJIN UNIV
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