Method and device for removing volatile impurities in aqueous solution and preparing crystal product through air circulation gas stripping concentration

A technology of air circulation and high-concentration aqueous solution, which is applied in the direction of solution crystallization, general layout of crystallization devices, evaporation, separation and crystallization, etc., and can solve the problems of limiting the industrial application of air lift and crystallization technology, large transfer resistance in the liquid phase, and gas-liquid interface. Weak driving force for mass transfer, etc.

Active Publication Date: 2022-03-29
SICHUAN UNIV
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  • Application Information

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Problems solved by technology

However, the high-concentration and high-viscosity solution not only has a large transfer resistance in the liquid phase, but also has a large drop in solution vapor pressure and a weak driving force for mass transfer at the gas-liquid interface, which limits the application of high-concentration and high-viscosity solution gas stripping and crystallization technology. industrial application

Method used

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  • Method and device for removing volatile impurities in aqueous solution and preparing crystal product through air circulation gas stripping concentration
  • Method and device for removing volatile impurities in aqueous solution and preparing crystal product through air circulation gas stripping concentration

Examples

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Embodiment 1

[0010] Example 1: Silver nitrate (AgNO 3 ) aqueous solution by gas stripping and concentrating to prepare 400kg / h of silver nitrate crystals.

[0011] as attached figure 1 As shown, 800 kg / h of silver nitrate aqueous solution with a temperature of 100 °C and a mass concentration of 82.34% is used as a raw material, and a 1000 kg / h air circulation is used to extract and concentrate the preparation amount of 400 kg / h of silver nitrate crystals. The cross-section of the corrugated plate array of the gas stripping and concentrating crystallizer 1 is an equilateral rectangle with a side length of 0.2m. The array is composed of 30 upright triangular corrugated plates with a width of 0.2m and a height of 0.5m uniformly arranged in the same direction. The spacing between the plates is 6.9mm. The distance is 30mm, and the corrugation inclination angle is 30°. The silver nitrate aqueous solution raw material is evenly distributed on the cross-section of the corrugated plate array by ...

Embodiment 2

[0012] Embodiment 2: to 50000kg / h concentration 55% (H 3 PO 4 ) of the wet-process phosphoric acid solution is stripped and concentrated for defluorination to increase its concentration to 70% (H 3 PO 4 ) above, fluorine does not exceed 0.05% (F).

[0013] as attached figure 2 As shown, the raw material wet-process phosphoric acid solution is 50000kg / h, the concentration is 55% (H 3 PO 4 ), containing 2% fluorine (F), temperature 40°C; use 22000kg / h air circulation to extract and concentrate defluorination, and increase its concentration to 70% (H 3 PO 4 ), the fluorine content is reduced to 0.05% (F). The cross-section of the corrugated plate array of the gas stripping and concentrating purifier 8 is an equilateral rectangle with a side length of 1.1m. The array is composed of 220 upright triangular corrugated plates with a width of 1.1m and a height of 2.8m evenly arranged in the same direction. The spacing between the plates is 5mm, and the corrugation pitch 30mm, ...

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Abstract

The invention relates to a method and a device for removing volatile impurities in an aqueous solution and preparing a crystal product through air circulation gas stripping concentration, which are characterized in that a group of vertical corrugated plate arrays, gas-liquid distribution structures respectively connected with the upper part and the lower part of the vertical corrugated plate arrays and the like form gas-liquid countercurrent flow heat and mass transfer on the surfaces of falling films on the two sides of corrugated plates; the purification effect that the water solution with the water content not lower than 40% and the volatile impurity not higher than 3.0% is concentrated till the water content is lower than 35% and the volatile impurity content is lower than 0.1% is achieved, and crystal mush with the ratio of the crystal particle amount to the total solute mass larger than 40% is prepared from the water solution with the water content not lower than 15%. And a constant mass flow air closed circulation system is formed by the pressure stabilizing tower and the constant pressure water seal tank. The method has the advantages that energy is saved, closed circulation is achieved, and emission is avoided, for example, the energy consumption for preparing 400 kg of silver nitrate crystals from the 82.34% silver nitrate aqueous solution does not exceed 5 kWh, and the energy consumption for air circulation for removing 1000 kg of fluorine from the wet-process phosphoric acid solution containing 2.0% of fluorine does not exceed 100 kWh.

Description

technical field [0001] The invention relates to inorganic chemical industry, recycling of resources and energy, energy saving and emission reduction, in particular to the technical field of removing volatile impurities in aqueous solution and crystallization by adopting air closed circulation to enhance heat and mass transfer. Background technique [0002] Separation of impurities is an essential step in the preparation of high-purity soluble products from aqueous solutions. The volatile impurities can be separated by removing the gaseous components of the aqueous solution (air stripping), or the product can be separated from the non-volatile impurities by extracting crystals from the aqueous solution. For example, the phosphoric acid (wet process phosphoric acid) aqueous solution obtained by the wet processing of phosphate rock contains various impurities contained in the ore, and the fluorine and silicon in it are easy to escape from the liquid phase of phosphoric acid wit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D9/02B01D3/38B01D3/42
CPCB01D9/0027B01D9/004B01D9/005B01D9/0059B01D9/0063B01D3/38B01D3/42
Inventor 朱家骅夏素兰李季葛敬
Owner SICHUAN UNIV
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