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
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  • 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

Method used

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  • 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

Example Embodiment

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

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

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

[0045] c. Transfer the product in the reaction tank to the crystallization tank, and add H into the crystallization tank 2 SO 4 , And form crystallization with calcium ions in the liquid phase to produce hemihydrate gypsum. The amount o...

Example Embodiment

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

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

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

[0051] c. Transfer the product in the reaction tank to the crystallization tank, and add H into the crystallization tank 2 SO 4 , And form crystallization with calcium ions in the liquid phase to produce hemihydrate gypsum. The amount of s...

Example Embodiment

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

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

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

[0057] c. Transfer the product in the reaction tank to the crystallization tank, and add H into the crystallization tank 2 SO 4 , And form crystallization with calcium ions in the liquid phase to produce hemihydrate gypsum. The amount of ...

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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

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Application Information

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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
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