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

Method for preparing phosphoric acid and co-produced gypsum powder by hemihydrate process

A technology of hemihydrate gypsum and gypsum powder, applied in chemical instruments and methods, phosphorus compounds, calcium/strontium/barium sulfate, etc., can solve the initial setting time, final setting time, 2h flexural resistance and compression resistance of hemihydrate gypsum The strength index cannot meet the standards of building gypsum, etc., to achieve the effect of reducing the amount of crystal nucleation, improving the crystal form, and reducing the viscosity of the slurry

Active Publication Date: 2017-01-25
GUIZHOU CHANHEN CHEM CO LTD
View PDF4 Cites 9 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is that the initial setting time, final setting time, 2h flexural and compressive strength indexes of the hemihydrate gypsum produced by co-production of phosphoric acid in the prior art cannot meet the construction gypsum standard

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
  • Method for preparing phosphoric acid and co-produced gypsum powder by hemihydrate process
  • Method for preparing phosphoric acid and co-produced gypsum powder by hemihydrate process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Example 1 Prepare phosphoric acid co-production gypsum powder with the method of the present invention

[0043] a. Add semi-water process crystallization tank slurry into the pre-reaction tank, and the index in the slurry is: P 2 o 5 : 42.05%, SO 4 2- : 1.47%, CaO: 0.15%, and then add 12kg to 12.5kg / h of phosphate rock with a moisture content of 12 to 13% into the pre-reaction tank to ensure that the SO in the liquid phase after the slurry is mixed with the phosphate rock 4 2- The molar ratio with CaO is 0.65:1, the reaction temperature is 93-98°C, and the reaction is 2-2.5 hours;

[0044] b. Transfer the product in the pre-reaction tank to the reaction tank to make the remaining SO in the slurry 4 2- Further fully react with CaO in phosphate rock at 93-98°C for 2.5 hours;

[0045] c. Transfer the product in the reaction tank to the crystallization tank, and add H in the crystallization tank 2 SO 4 , to form crystals with calcium ions in the liquid phase to for...

Embodiment 2

[0048] Example 2 Prepare phosphoric acid co-production gypsum powder with the method of the present invention

[0049] a. Add semi-water process crystallization tank slurry into the pre-reaction tank, and the index in the slurry is: P 2 o 5 : 42.05%, SO 4 2- : 1.47%, CaO: 0.15%, and then add 12kg to 12.5kg / h of phosphate rock with a moisture content of 12 to 13% into the pre-reaction tank to ensure that the SO in the liquid phase after the slurry is mixed with the phosphate rock 4 2- The molar ratio with CaO is 0.6:1, the reaction temperature is 93-98°C, and the reaction is 2.5 hours;

[0050] b. Transfer the product in the pre-reaction tank to the reaction tank to make the remaining SO in the slurry 4 2- Further fully react with CaO in phosphate rock at 93-98°C for 2.5 hours;

[0051] c. Transfer the product in the reaction tank to the crystallization tank, and add H in the crystallization tank 2 SO 4 , to form crystals with calcium ions in the liquid phase to form h...

Embodiment 3

[0054] Example 3 Prepare phosphoric acid co-production gypsum powder with the method of the present invention

[0055] a. Add semi-water process crystallization tank slurry into the pre-reaction tank, and the index in the slurry is: P 2 o 5 : 42.05%, SO 4 2- : 1.47%, CaO: 0.15%, and then add 12kg to 12.5kg / h of phosphate rock with a moisture content of 12 to 13% into the pre-reaction tank to ensure that the SO in the liquid phase after the slurry is mixed with the phosphate rock 4 2- The molar ratio with CaO is 0.75:1, the reaction temperature is 93-98°C, and the reaction is 2.5 hours;

[0056] b. Transfer the product in the pre-reaction tank to the reaction tank to make the remaining SO in the slurry 4 2- Further fully react with CaO in phosphate rock at 93-98°C for 2.5 hours;

[0057] c. Transfer the product in the reaction tank to the crystallization tank, and add H in the crystallization tank 2 SO 4 , to form crystals with calcium ions in the liquid phase to form ...

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 invention belongs to the technical field of phosphorus chemical industry production, and particularly relates to a method for producing phosphoric acid and co-produced gypsum powder by a hemihydrate process. The method for producing the phosphoric acid and co-produced gypsum powder by the hemihydrate process, provided by the invention, is used for solving the problem that co-produced gypsum of the existing hemihydrate processes cannot reach standards of building gypsum. The method provided by the invention comprises the following steps: returning slurry of a crystallizing tank to a pre-reaction tank, and enabling the slurry to make a pre-reaction with phosphorite; in a reaction tank, enabling SO4<2-> remaining in the returned slurry to make a further full reaction with CaO in the phosphorite; adding H2SO4 into the crystallizing tank so as to obtain semi-hydrated gypsum, and carrying out filtrating, washing and free-water removal, thereby obtaining the gypsum powder, of which the length-diameter ratio is (2 to 10): 1. The setting time, breaking strength and compression strength of the gypsum powder prepared by adopting the process are superior to those required in the standards of the building gypsum. The method has the advantages that the energy consumption is lowered, process flows are shortened, the difficulty of subsequent treatment of gypsum produced during the preparation of phosphoric acid by the hemihydrate process is lowered, the range of utilization of ardealite is widened, and the pile-up pressure of gypsum storage yards is lightened.

Description

technical field [0001] The invention belongs to the technical field of phosphorus chemical production, and in particular relates to a method for preparing phosphoric acid co-production gypsum powder by a semi-aqueous process. Background technique [0002] In the production process of wet-process phosphoric acid, with the different process conditions such as slurry temperature, phosphoric acid concentration, and sulfuric acid dosage in the reaction process, CaSO 4 There are three different forms of hydrates, namely dihydrate, hemihydrate and anhydrate. Generate CaSO 4 Depending on the crystal form, the production process of wet-process phosphoric acid mainly includes dihydrate process, semi-hydrate process, semi-hydrate-dihydrate process and dihydrate-semi-hydrate process. At present, the vast majority of phosphoric acid production adopts the dihydrate process, but the hemihydrate process is gradually developing due to its advantages of low energy consumption, saving sulfur...

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): C01B25/226C01F11/46
CPCC01B25/226C01F11/46
Inventor 曾春华李顺方李剑秋马永强石建华龙辉
Owner GUIZHOU CHANHEN CHEM CO LTD
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

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com