Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Process for preparing alpha-semi-hydrated gypsum from modified gypsum at normal pressure

A technology of gypsum and hemihydrate gypsum, applied in the direction of calcium/strontium/barium sulfate, etc., can solve the problems of large capital increase, high production cost, complicated equipment, etc.

Active Publication Date: 2005-01-26
ZHEJIANG TIANLAN ENVIRONMENTAL PROTECTION TECH
View PDF1 Cites 7 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Both methods need to be carried out under a certain steam pressure, the equipment is complicated, the investment is large, and the production cost is high

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Process for preparing alpha-semi-hydrated gypsum from modified gypsum at normal pressure
  • Process for preparing alpha-semi-hydrated gypsum from modified gypsum at normal pressure
  • Process for preparing alpha-semi-hydrated gypsum from modified gypsum at normal pressure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Crush raw gypsum to a certain particle size, add a certain proportion of salt solution to the slurry mixing tank, and prepare a slurry with a concentration of about 10-20%, the total concentration of the crystallization agent is 10%, and the composition is: CaCl 2 0.1%, MgCl 2 1%, KCl4.9%, Borax 4%. After mixing evenly, heat up to 90°C through a heat exchanger and enter the crystallizer for a residence time of 2 to 4 hours while stirring. After the crystal form changes, it enters the downcomer and is sent to the product tank at the lower part. The temperature in the product tank is continuously controlled at 90°C to make the crystal continue to grow. Monitor slurry density > 1000Kg / m 3 Finally, extract the slurry and send it to the cyclone to separate the solid and liquid. The large crystals in the lower part can be separated by centrifugation, washed with fresh water, sent to the boiling dryer for drying, and then transported and packaged. The slurry containing smal...

Embodiment 2

[0028]Crush the raw gypsum to a certain particle size, add a certain ratio of salt solution to the slurry tank, and prepare a slurry with a concentration of about 10-20%. The total concentration of the crystallization agent is 15%, and the composition is: CaCl 2 5%, MgCl 2 10%, KCl3%, Borax 2%. After mixing evenly, heat up to 95°C through a heat exchanger and enter the crystallizer for a residence time of 2 to 4 hours while stirring. When the crystal form changes, it enters the downcomer and is sent to the lower product tank. The temperature in the product tank is continuously controlled at 95°C to make the crystal continue to grow. Monitor slurry density > 1000Kg / m 3 Finally, extract the slurry and send it to the cyclone to separate the solid and liquid. The large crystals in the lower part can be separated by centrifugation, washed with fresh water, sent to the boiling dryer for drying, and then transported and packaged. The slurry containing small particles separated fro...

Embodiment 3

[0030] Crush raw gypsum to a certain particle size, add a certain ratio of salt solution to the slurry mixing tank, and prepare a slurry with a concentration of about 10-20%. The total concentration of the crystallization agent is 20%, and the composition is: CaCl 2 5%, MgCl 2 5%, KCl5%, borax 5%. After mixing evenly, heat up to 90°C through a heat exchanger and enter the crystallizer for a residence time of 2 to 4 hours while stirring. After the crystal form changes, it enters the downcomer and is sent to the product tank at the lower part. The temperature in the product tank is continuously controlled at 90°C to make the crystal continue to grow. Monitor slurry density > 1000Kg / m 3 Finally, extract the slurry and send it to the cyclone to separate the solid and liquid. The large crystals in the lower part can be separated by centrifugation, washed with fresh water, sent to the boiling dryer for drying, and then transported and packaged. The slurry containing small particl...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The disclosed semi-hydrated gypsum preparing process consists of, charging a finite proportion or salt solution into crude gypsum for crystallization under normal pressure, separating liquid-solid phase, subjecting the separated alpha-semi-hydrated gypsum to washing, drying, and packaging. Said salt solution comprises alkali metal chloride, the soluble salts of alkaline-earth metal and borax.

Description

technical field [0001] The invention relates to a process for preparing alpha-hemihydrate gypsum, in particular to a process for preparing alpha-hemihydrate gypsum by modifying raw gypsum under normal pressure. Background technique [0002] At present, raw gypsum (CaSO 4 2H 2 O) Preparation of α-hemihydrate gypsum (CaSO 4 1 / 2H 2 (2) The commonly used methods are autoclave steaming method and reaction kettle solution method. Both methods need to be carried out under a certain steam pressure, the equipment is complicated, the investment is large, and the production cost is high. [0003] In the invention patent application with the patent application number 03142607.7, the applicant proposed a process for producing α-hemihydrate desulfurized gypsum by the normal pressure salt solution method, including: (1) Precipitating calcium sulfite in the precipitation tank in the desulfurization process The slurry is sent to the oxidation tank to be fully oxidized under the conditio...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): C01F11/46C04B11/02
Inventor 吴忠标吴晓琴程常杰官宝红王毅
Owner ZHEJIANG TIANLAN ENVIRONMENTAL PROTECTION TECH
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products