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Method and device for preparing high-strength alpha hemihydrate gypsum by using phosphogypsum

A technology of hemihydrate gypsum and phosphogypsum, which is applied in the field of comprehensive utilization of solid waste, can solve the problems of difficult application of phosphogypsum and high cost of production technology, and achieve the effects of improving steam curing and drying efficiency, low cost, and sufficient reaction

Inactive Publication Date: 2015-05-20
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0021] Aiming at the defects of the above-mentioned several processes, the present invention proposes a method for preparing high-strength α-hemihydrate gypsum from phosphogypsum. This method overcomes the shortcomings of traditional α-hemihydrate gypsum production technology with high cost and difficult application of phosphogypsum, and develops a new A new process for preparing α hemihydrate gypsum from phosphogypsum with low cost and low energy consumption, and solve the key technology for efficient utilization of α hemihydrate gypsum prepared from a large amount of phosphogypsum

Method used

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  • Method and device for preparing high-strength alpha hemihydrate gypsum by using phosphogypsum

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Effect test

Embodiment 1

[0043] Embodiment 1: The specific steps of the method for preparing high-strength α hemihydrate gypsum from this phosphogypsum are as follows:

[0044] (1) Mix phosphogypsum, pretreatment additives, water, and crystal modifier, and stir evenly. After aging for 1 day, press the mixture into balls at a pressure of 15Mpa. The amount of pretreatment additive CaO is the mass of phosphogypsum 2% of phosphogypsum, the amount of water added is 12% of the mass of phosphogypsum, and the amount of sodium citrate and aluminum sulfate added in the crystal transformation agent is 0.04% of the mass of phosphogypsum respectively;

[0045] (2) Put the pelletized material in a closed autoclave, use high-temperature saturated water vapor at 117°C for 4 hours at a pressure of 0.17Mpa, then reduce the pressure and use hot air to heat and dry the reaction product, collect the product after cooling down, and grind it Afterwards, high-strength α-hemihydrate gypsum was obtained, and its performance wa...

Embodiment 2

[0048] Embodiment 2: The specific steps of the method for preparing high-strength α hemihydrate gypsum from this phosphogypsum are as follows:

[0049] (1) Mix phosphogypsum, pretreatment additives, water, and crystal modifier, and stir evenly. After aging for 2 days, press the mixture into balls at a pressure of 5Mpa. The amount of pretreatment additive CaO is the mass of phosphogypsum 4% of phosphogypsum, the addition of water is 8% of the mass of phosphogypsum, and the addition of sodium citrate and aluminum sulfate in the crystal transformation agent is 0.02% of the mass of phosphogypsum respectively;

[0050] (2) Put the pelletized material in a closed autoclave, and use high-temperature saturated water vapor at 134°C to treat it at a pressure of 0.3Mpa for 5 hours, then use hot air to heat and dry the reaction product, collect the product after lowering the temperature and pressure, and grind it After that, high-strength α-hemihydrate gypsum was obtained, and its perfor...

Embodiment 3

[0052] Embodiment 3: The specific steps of the method for preparing high-strength α hemihydrate gypsum from this phosphogypsum are as follows:

[0053] (1) Mix phosphogypsum, pretreatment additives, water, and crystal modifier, and stir evenly. After aging for 1.5 days, press the mixture into balls at a pressure of 20Mpa. The amount of pretreatment additive CaO is the mass of phosphogypsum 3%, the addition of water is 6% of the mass of phosphogypsum, and the addition of sodium citrate and aluminum sulfate in the crystal transformation agent is 0.08% of the mass of phosphogypsum respectively;

[0054] (2) Put the pelletized material in a closed autoclave, use high-temperature saturated water vapor at 160°C for 2 hours at a pressure of 0.6Mpa, then use hot air to heat and dry the reaction product, collect the product after cooling down, and grind it After that, high-strength α-hemihydrate gypsum was obtained, and its performance was tested by conventional methods. The flexural ...

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Abstract

The invention discloses a method for preparing high-strength alpha hemihydrate gypsum by using phosphogypsum. The method comprises the following steps of: mixing the phosphogypsum, a pretreatment additive, water and a crystal modifier, stirring to be uniform, forming balls after aging treatment, then finishing steam curing and drying in a stilling kettle, and preparing the high-strength alpha hemihydrate gypsum. The method disclosed by the invention has the advantages that the process flow is simple, the industrialization is easy, the phosphogypsum can be greatly utilized and consumed, and the conversion rate is high; and simultaneously, the invention provides the stilling kettle capable of realizing integration of steam curing and drying, the alpha hemihydrate gypsum can be better prepared, and the high-quality building material or wall-body material can be better prepared.

Description

technical field [0001] The invention belongs to the field of comprehensive utilization of solid waste, and in particular relates to a method and a device for preparing high-strength alpha hemihydrate gypsum from phosphogypsum. Background technique [0002] α hemihydrate gypsum, known internationally as high-strength gypsum, has the main feature that the basic compressive strength can reach 40-60MPa, or even 100MPa. At present, the gypsum material commonly used in China is β hemihydrate gypsum prepared by calcining, also known as "building gypsum", and its basic strength is only about 5-10MPa. [0003] α-type hemihydrate gypsum is generally considered to belong to the trigonal system and layered structure. When dihydrate gypsum is converted into hemihydrate gypsum, two types of changes will occur: one is that the water molecules between the two ion layers lose 3 / 4; the other is that Ca 2+ with SO4 2- staggered from each other. α-type hemihydrate gypsum and β-type hemihyd...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B11/26
Inventor 李建锡
Owner KUNMING UNIV OF SCI & TECH
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