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Anhydrous II-type gypsum and preparation method thereof

A gypsum and phosphogypsum technology, applied in the field of comprehensive utilization of solid waste resources, can solve the problems affecting the use range of products, poor product quality stability, low added value, etc., achieve good water resistance and mechanical strength, increase the scope of application, and improve water resistance. sexual effect

Active Publication Date: 2022-05-27
SICHUAN LOMON IND GYPSUM DEV CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003]Currently, phosphogypsum is mainly used in the production of cement retarder, β-type building gypsum powder and a small amount of α-type high-strength building gypsum powder, anhydrous type II gypsum powder. The overall added value is low; secondly, limited by the characteristics of phosphogypsum itself, it carries a certain amount of free acid, organic matter and other impurities, resulting in poor product quality stability and many problems in marketing; thirdly, its own characteristics , the gypsum powder product exists in the form of CaSO4·2H2O after hydration. Due to the slightly soluble nature of calcium sulfate, the hydrated crystal structure will After that, it will be sheared and damaged to cause strength loss, which directly affects the range of use of the product.

Method used

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  • Anhydrous II-type gypsum and preparation method thereof
  • Anhydrous II-type gypsum and preparation method thereof
  • Anhydrous II-type gypsum and preparation method thereof

Examples

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Embodiment 1

[0021] A preparation method of anhydrous type II gypsum, comprising the following preparation steps:

[0022] S1: Mix undisturbed phosphogypsum 70% wt, calcium oxide 4% wt, calcium carbonate 1% wt, aluminate clinker 15% wt and fly ash 10% wt after wet grinding for 30 minutes, and control the free water content to 20% wt.

[0023] S2: add triethanolamine 0.1%wt, diethanolmonoisopropanolamine 0.1%wt, and sodium tripolyphosphate 0.2%wt to the mixture in step S1, mix and place in a microwave radiation field at 150° C. for 0.4h.

[0024] S3: after calcining the product of step S2 at 700° C. for 1.5 hours, grinding to a specific surface area of ​​400±50 m2 / kg to obtain anhydrous type II gypsum.

Embodiment 2

[0026] The basic steps of Example 2 are the same as those of Example 1, except that in step S1 of Example 2, calcium oxide is 1%wt, aluminate clinker is 10%wt, fly ash is 30%, and undisturbed phosphogypsum is 69%wt , the wet grinding time is 15 minutes, and the free water content is controlled to be 25% wt.

Embodiment 3

[0028] The basic steps of Example 3 are the same as those of Example 1, except that in step S1 in Example 3, calcium oxide is 5% wt, and aluminate clinker is 20% wt. The fly ash is 10%wt, the original phosphogypsum is 75%wt, the wet grinding time is 60min, and the free water content is controlled to be 15%wt.

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Abstract

The invention relates to the field of comprehensive utilization of solid waste resources, and provides a preparation method of anhydrous II-type gypsum, which comprises the following steps: mixing undisturbed phosphogypsum, calcium salt, fly ash and aluminate clinker, grinding, placing the ground mixture in microwave radiation to regulate and control the growth of the mixture, and drying to obtain the anhydrous II-type gypsum. And finally, calcining the product, and adding a water reducing agent to obtain the anhydrous II-type gypsum. The invention also provides the anhydrous II-type gypsum prepared by the method, the anhydrous II-type gypsum has good water resistance and compressive strength, and the problem of industrial waste residues of phosphogypsum can be relieved to a certain extent.

Description

technical field [0001] The invention relates to the technical field of comprehensive utilization of solid waste resources, and relates to anhydrous type II gypsum and a preparation method thereof. Background technique [0002] In the production process of wet phosphoric acid, every 1 ton of phosphoric acid produced (with P 2 O 5 The by-product is about 5 tons of phosphogypsum, and the output of solid waste is large. Most of the enterprises are mainly stockpiled, which not only occupies a lot of land resources, but also increases the investment in the construction of enterprise slag warehouses, resulting in waste of resources. At the same time, long-term stockpiling may also cause Groundwater pollution and other issues. In order to reduce the stockpile of phosphogypsum and increase the utilization ratio of phosphogypsum, government departments have introduced various measures to encourage enterprises to increase the research and application of comprehensive utilization tech...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B11/26C04B11/02C04B11/024
CPCC04B11/26C04B11/02C04B11/024Y02W30/91
Inventor 仲一夫付全军张珂泽廖延武钟世林刘奎安天华
Owner SICHUAN LOMON IND GYPSUM DEV CO LTD