Method of preparing funnel-shaped sodium sulfate from high salt wastewater

A high-salt wastewater, anhydrous sodium sulfate technology, applied in the preparation form of alkali metal sulfite/sulfate, chemical instruments and methods, alkali metal sulfite/sulfite and other directions, to achieve extended residence time, large distribution , the effect of improving the dissolution rate

Active Publication Date: 2019-04-09
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, at present, the focus of the method for preparing sodium sulfate from wastewater in the patent literature is still on the feasibility of the

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  • Method of preparing funnel-shaped sodium sulfate from high salt wastewater
  • Method of preparing funnel-shaped sodium sulfate from high salt wastewater
  • Method of preparing funnel-shaped sodium sulfate from high salt wastewater

Examples

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Effect test

Embodiment 1

[0033] Add 120mL of waste water (density 1.2g / mL) containing 28% (mass percent) sodium sulfate to a 150mL crystallizer, control the stirring rate to 200rpm, add sodium hydroxide to adjust the pH value to 11, and heat to 80°C after constant temperature, Start to use negative pressure evaporation, the vacuum degree is controlled to 0.04MPa, and the evaporated water volume is 30mL. Then filter, place the wet solid phase at 105°C, and dry under normal pressure for 8 hours to constant weight to obtain a funnel-shaped sodium sulfate product. The moisture content of the product is 4.63%, and the purity is 98.45%. The photos of the product as a whole and the micrographs and electron micrographs of individual particles are as follows: figure 1 with figure 2 (The short line in the lower right corner of the figure indicates that the length is 200 μm, and the edge and endpoint of the funnel-shaped crystal are marked with a white dotted line and a white dot, respectively.) As shown, the ...

Embodiment 2

[0035] Add 120mL of waste water containing 28% (mass percent) sodium sulfate to a 150mL crystallizer, control the stirring rate to 100rpm, add sodium hydroxide to adjust the pH value to 14, heat to 50°C after constant temperature, start to use negative pressure evaporation, vacuum The degree of control is 0.07MPa, and the amount of distilled water is 35mL. After 50 seconds of filtration, the wet solid phase was completely placed at 105°C, and dried under normal pressure for 8 hours to constant weight to obtain a funnel-shaped sodium sulfate product. The moisture content of the product is 5.56%, the purity is 96.63%, the distribution range of the cone angle of the funnel is 120-150°, and the mass percentage of the product with a particle size ≥ 300 μm is 90.22%.

Embodiment 3

[0037] Add 120mL of waste water containing 30% (mass percent) sodium sulfate to a 150mL crystallizer, control the stirring rate to 400rpm, add sodium hydroxide to adjust the pH value to 12, heat to 60°C after constant temperature, start to use negative pressure evaporation, vacuum The degree of control is 0.05MPa, and the amount of distilled water is 30mL. Then filter, place the wet solid phase at 105°C, and dry under normal pressure for 10 hours to constant weight to obtain a funnel-shaped sodium sulfate product. The moisture content of the product is 7.03%, the purity is 95.88%, the distribution range of the cone angle of the funnel is 120-150°, and the mass percentage of the product with a particle size ≥ 300 μm is 91.35%.

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Abstract

The invention relates to a method of preparing funnel-shaped sodium sulfate from high salt wastewater. The method comprises the following steps: heating the wastewater to 50-80 DEG C, adding sodium hydroxide to adjust the pH of the wastewater to 11-14, and controlling the stirring rate at 100-400 rpm; adopting a negative evaporative crystallizing mode till the volume of the evaporated water is 20-30% of original wastewater volume, wherein the vacuum degree is 0.04-0.07 MPa; and filtering and drying the obtained product to obtain the funnel-shaped sodium sulfate. The cone angle of the funnel ofthe sodium sulfate product with a special funnel-shaped crystal form is 120-150 degrees and the purity of sodium sulfate is greater than or equal to 95%. The granularity of particles is relatively great and the particles are distributed uniformly, and the grain size of the product is greater than or equal to 300 [mu]m.

Description

technical field [0001] The invention relates to a process for crystallization and desalination of pharmaceutical wastewater mainly containing sodium sulfate, in particular to a funnel-shaped sodium sulfate that can be efficiently recovered from pharmaceutical wastewater and a preparation method thereof. Background technique [0002] Sodium sulfate (Sodium sulfate), chemical formula Na 2 SO 4 , also known as anhydrous Glauber's salt, as a common inorganic salt, its solubility shows a decreasing inverse solubility trend with the increase of temperature, and maintains a solid-liquid balance in the form of sodium sulfate decahydrate in a saturated aqueous solution at room temperature . Therefore, the industry usually adopts the mode of evaporative crystallization to make anhydrous sodium sulfate product. [0003] At present, the domestic production of sodium sulfate is mainly prepared through the comprehensive mining of sulfate mines and salt lake brine resources. At the sam...

Claims

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Application Information

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IPC IPC(8): C01D5/00
CPCC01D5/004C01P2004/03C01P2004/60C01P2006/80
Inventor 龚俊波杨静朱培培侯宝红王召
Owner TIANJIN UNIV
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