Method for recovering potassium nitrate from anthraquinone dye alkali wastewater

A recovery method and anthraquinone technology are applied in the field of recycling and reuse of printing and dyeing wastewater, which can solve the problems of immature technology, high equipment requirements, and unsatisfactory effects, and achieve the effects of saving treatment costs, high removal rates, and improved effects.

Active Publication Date: 2014-08-13
ZHEJIANG QICAI ECO TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The cost of single adsorption method is high and the effect is not ideal, and the other methods are not mature enough and require high equipment

Method used

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  • Method for recovering potassium nitrate from anthraquinone dye alkali wastewater
  • Method for recovering potassium nitrate from anthraquinone dye alkali wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] In this example, alkaline wastewater (pH = 13, COD = 211000mg / L) is subjected to acid analysis first, acid analysis is only performed once, and concentrated nitric acid (concentration: 65%), which accounts for 25% of the wastewater mass, is added to stir and react for 1.5 Add activated carbon accounting for 0.4% of the waste water mass after one hour, continue to stir and react for 1 hour, and filter; the COD of the filtrate is about 121000mg / L. Slowly add concentrated nitric acid accounting for 4% of the waste water mass to this filtrate, keep warm at 85-95°C, stir for 4 hours, cool down to 40-50°C, and filter. After the filtrate is concentrated, the color of the obtained salt is reddish brown. After adding 15% washing water, the salt is still slightly yellow, and the COD of the condensed water is greater than 1000mg / L.

Embodiment 2

[0028] Add concentrated nitric acid with a mass fraction of 65% to alkaline wastewater (pH=13, COD=211000mg / L), keep the wastewater pH=4, stir and react for 1 hour, consume 20% of the acid, and then add 0.3% of the total mass of the wastewater to be treated The activated carbon was stirred and reacted for 0.5 hours and then filtered, the filtrate COD=104100mg / L, the COD removal rate was about 51%, but the chroma was still relatively large; 5% concentrated nitric acid was added to the filtrate, and 0.1% was added after stirring for 0.5 hours The activated carbon was stirred and reacted for 0.5 hour, and filtered to obtain about 80000 mg / L of wastewater COD. Raise the temperature of the waste water to 85-95°C, while slowly adding concentrated nitric acid, while bubbling with the air, and stirring constantly, keep warm for 4 hours, add 4% nitric acid in total, cool down to 40-50°C and then filter, the filtrate is wine red, COD=10000mg / L, then add 0.1% activated carbon to stir and...

Embodiment 3

[0031] The setting and working principle of this example are the same as those of Example 2, the difference is that after the nitric acid is oxidized and filtered directly without adding activated carbon, the obtained salt is wine red, and after washing with 25% washing water, it is still slightly yellow, and the condensed water is orange-red , COD about 700mg / L.

[0032] Can find out by embodiment 3: directly filter after nitric acid oxidation, the salt color that obtains is darker, and the washing water consumption increases, and condensed water COD and chromaticity all rise.

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Abstract

The invention relates to a method for recovering potassium nitrate from anthraquinone dye alkali wastewater and belongs to the technical field of recovery and recycle of printing and dyeing wastewater. The method comprises the following steps of adding nitric acid into collected alkali wastewater, carrying out primary acidification with stirring for primary acidification time of 0.5-12h, when a solution pH value is in a range of 1-4, adding an adsorbent, a neutral flocculating agent or an acidic flocculating agent into the solution so that a precipitation reaction occurs, filtering the reaction product, adding nitric acid into the solution, carrying out secondary acidification with stirring for secondary acidification time of 0-8h, when a solution pH value is in a range of 3-5h, adding an adsorbent, a neutral flocculating agent or an acidic flocculating agent into the solution so that a precipitation reaction occurs, filtering the reaction product, and carrying out HNO3 oxidation, decoloring, condensation and salt-leaching so that a qualified industrial salt is obtained. The method is used for anthraquinone dye alkali wastewater, can realize recovery of a large amount of potassium nitrate, can remove organic matters in wastewater, can reduce a COD value of the wastewater, and can recover and recycle potassium nitrate.

Description

technical field [0001] The invention relates to a method for recovering potassium nitrate in alkaline wastewater of anthraquinone dyes, and belongs to the technical field of recovery and reuse of printing and dyeing wastewater. Background technique [0002] At present, the latest treatment methods for anthraquinone dye wastewater in China mainly include: coagulation precipitation-Fenton catalytic oxidation method, anaerobic-aerobic treatment method, micro-electrolysis-catalytic oxidation method, Penicillium method, electron beam decolorization method, etc. The coagulation-sedimentation-Fenton catalytic oxidation method and micro-electrolysis-catalytic oxidation method produce a large amount of unusable solid waste and have high cost. The biological method has poor adaptability and unstable operation. The electron beam decolorization method is still in the research stage and the technology is immature. Medicinal adsorption method for basic dye wastewater, ultrasonic enhanced ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C01D9/04
Inventor 张毅张云保
Owner ZHEJIANG QICAI ECO TECH CO LTD
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