Method for preparing hemihydrate gypsum gel material and gypsum products on line by using phosphogypsum at hot stage

Abstract

The invention relates to a method for preparing a hemihydrate gypsum gel material and gypsum products on line by using phosphogypsum at a hot stage. The method comprises the following steps: 1) phosphogypsum hot-state on-line processing process: scrubbing phosphogypsum discharged on line by using a water scrubbing process in the presence of a modifier and dehydrating to obtain phosphogypsum slurry; 2) phosphogypsum hot-state on-line hydrothermal preparation process: sufficiently mixing the phosphogypsum slurry with an activity agent and a crystal modifier to form material slurry and carrying out normal-pressure dynamic heat preservation reaction on the slurry material; carrying out solid-liquid separation to obtain hemihydrate gypsum slurry, wherein the scrubbing solution can be recycled after being treated; and 3) on-line preparation process of the hemihydrate gypsum gel material: washing the hemihydrate gypsum slurry with hot water, filtering and drying to obtain hemihydrate gypsum powder; or on-line preparation process of the phosphogypsum products: washing the hemihydrate gypsum slurry, filtering and directly preparing into building blocks, gypsum boards and other products online. The method has the advantages that the flotation process of phosphogypsum ore is omitted and phosphogypsum generated by a phosphorus chemical industry production line can be directly subjected to a normal-pressure hydrothermal reaction.

Description

technical field [0001] The invention belongs to the field of preparing gypsum cementitious materials by using phosphogypsum as a raw material, and in particular relates to a method for preparing hemihydrate gypsum cementitious materials and gypsum products on-line in a hot state using phosphogypsum. Background technique [0002] Gypsum is the main raw material for the production of cementitious materials and gypsum building products. The preparation process of gypsum cementitious materials is mainly the process of heating and dehydrating dihydrate gypsum into different dehydrated gypsum phases. After heating the dihydrate gypsum to a certain temperature, the gypsum loses part of its crystallization water and obtains hemihydrate gypsum. Hemihydrate gypsum is an air-hardening gelling material, which has two forms of α and β, and the two have no essence in microscopic appearance. difference, but their macroscopic properties are quite different. α-type hemihydrate gypsum is den...

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Problems solved by technology

[0006] In terms of dehydration of phosphogypsum to prepare hemihydrate gypsum, the current method of preparing α hemihydrate gypsum by atmospheric pressure hydrothermal method is relatively common, but the preparation of hemihydrate gypsum is gelled by using phosphogypsum discharged on-line with heat of 65°C-75°C Materials and methods for gypsum products have not yet emerged

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