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Method for preparing high-purity alpha-semi-hydrated gypsum powder through salt chemical byproducts

A by-product, gypsum powder technology, applied in the direction of calcium/strontium/barium sulfate, etc., can solve the problems of many impurities, limited application, poor purity and whiteness of α-hemihydrate gypsum, etc., achieve high purity and improve macroscopic mechanical properties Performance, 3D effect of dry compressive strength

Inactive Publication Date: 2016-08-24
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, in the current relevant research, most of the raw materials are natural gypsum or chemical gypsum, and there is no research on the preparation of calcium chloride and sodium sulfate, which are excess by-products of salt chemical industry. - Hemihydrate gypsum generally has poor purity and whiteness, which limits its application in higher-end biomedical and precision molds, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The technical grade sodium sulfate is formulated into a sodium sulfate solution with a temperature of 30°C and a concentration of 5wt%. 2 SO 4 0.01% nano-scale silicon dioxide of the solution mass is used as a nucleating agent; the calcium chloride slurry is adjusted to a calcium chloride solution with a temperature of 30°C and a concentration of 10wt%; Proportionally mixed, the mixing time is controlled to be 5min, and the mixed slurry is kept at a stirring rate of 30rpm and a temperature of 30°C for 1h to obtain a hydrothermal reaction precursor slurry, which is washed with water until c(Na + )=0.87wt%, dried at a temperature of 50°C to obtain a high-purity hydrothermal reaction precursor for subsequent use; the above-mentioned high-purity hydrothermal reaction precursor is mixed with an active agent prepared from sodium sulfate with a concentration of 10wt.%, and the solid-to-liquid ratio (1:2), then add 0.01% of the mass of the hydrothermal reaction precursor compo...

Embodiment 2

[0025] The technical grade sodium sulfate is formulated into a sodium sulfate solution with a temperature of 38°C and a concentration of 15wt.%. 2 SO 4 0.04% of the solution mass of nano-scale silicon dioxide as a nucleating agent; the calcium chloride slurry is adjusted to a temperature of 45 ° C, a calcium chloride solution with a concentration of 30wt.%; the above two solutions are just completely reacted with the solute The mixing ratio is mixed, and the mixing time is controlled to be 10min. The mixed slurry is kept at a stirring rate of 50rpm and a temperature of 40°C for 1.5h to obtain a hydrothermal reaction precursor slurry, which is washed with water until c(Na + )=0.74wt%, dried at a temperature of 60°C to obtain a high-purity hydrothermal reaction precursor for subsequent use; the above-mentioned high-purity hydrothermal reaction precursor and a concentration of 20wt.% sodium sulfate are formulated as active agent solutions according to (2: 1) mixed with a solid-t...

Embodiment 3

[0027] The technical grade sodium sulfate is formulated into a sodium sulfate solution with a temperature of 47°C and a concentration of 30wt.%. 2 SO 40.07% nano-scale silicon dioxide of the solution mass is used as a nucleating agent; the calcium chloride slurry is adjusted to a calcium chloride solution with a temperature of 75°C and a concentration of 60wt.%; the above two solutions are just completely reacted with the solute The mixing ratio is mixed, and the mixing time is controlled to be 15min. The mixed slurry is kept at a stirring rate of 80rpm and a temperature of 55°C for 2.5h to obtain a hydrothermal reaction precursor slurry, which is washed with water until c(Na + )=0.52wt%, dried at a temperature of 80°C to obtain a high-purity hydrothermal reaction precursor for subsequent use; the above-mentioned high-purity hydrothermal reaction precursor and a concentration of 30wt. : 1) mixed with a solid-to-liquid ratio, and then added 0.35% of the hydrothermal reaction p...

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Abstract

The invention relates to a method for preparing high-purity alpha-semi-hydrated gypsum powder through salt chemical byproducts. The method includes the following steps that 1, at the temperature of 30-50 DEG C, a nucleating agent is added into a salt chemical surplus product sodium sulfate solution, after full dispersion, the mixture is mixed with the salt chemical byproduct calcium chloride solution at the temperature of 30-90 DEG C, mixed slurry is obtained, heat is preserved for 1-3 h at the temperature of 30-70 DEG C, then washing and drying are conducted, and a hydrothermal reaction precursor is obtained; 2, the hydrothermal reaction precursor is mixed with an activity agent solution, a crystal modifier, a surfactant and a thickener are added, the material is mixed to be uniform, the mixture is put in a hydrothermal reaction still for a reaction, then drying is conducted, and the high-purity alpha-semi-hydrated gypsum powder is obtained. The prepared gypsum powder can be applied to the fields of high-end building materials, bio-medical treatment, precision molds and the like, the burden of salt chemical enterprises adopting an ammonia soda process for difficult disposal of a large quantity of calcium chloride is greatly relieved, and low-carbon high-value-added utilization of the salt chemical surplus byproducts calcium chloride and sodium sulfate is achieved.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment and resource utilization, and relates to a method for preparing high-purity α-hemihydrate gypsum powder by using salt chemical by-products. Background technique [0002] At this stage, the process of preparing soda ash by "ammonia-soda method" is still widely used in salt chemical enterprises. This process produces a large amount of calcium chloride by-product. Calcium chloride has a wide range of uses in chemical, food, pharmaceutical and other fields. It is used as deicing agent, desiccant, and additive in chemical production, but it is generally used in small batches, so calcium chloride is difficult to handle, and random storage will occupy a large amount of land resources, endanger groundwater quality, and seriously affect salt chemical enterprises. development of. Another important product of salt chemical industry, sodium sulfate, is mainly used in the preparation of water gl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/46
CPCC01F11/46C01P2006/80
Inventor 马保国卢文达苏英李玉博贺行洋高超李显良金子豪
Owner WUHAN UNIV OF TECH
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