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Recycling method for electrode foil-corrosion waste nitric acid

An electrode foil and waste nitric acid technology, which is applied in the directions of nitric acid, aluminum nitrate, nitrogen oxides/oxyacids, etc., can solve the problems of inability to treat printing and dyeing wastewater, high input of raw materials, and danger of waste acid, and achieve low treatment costs. , The effect of high reaction temperature and high operating cost

Active Publication Date: 2018-10-30
常州中源工程技术有限公司
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This waste acid not only contains a small amount of free sulfuric acid, but also contains aluminum ions corroded from the aluminum foil. The waste acid can be sent to printing and dyeing enterprises. Since the pH of printing and dyeing wastewater is about 11-12, the waste acid mainly contains Al 3+ 、H + , Cl - , NO 3 - etc. It can neutralize the pH of wastewater and has flocculation effect, so it is a good agent for printing and dyeing wastewater treatment, and will not have adverse effects on wastewater treatment equipment. Although the wastewater has a certain effect when used in printing and dyeing wastewater, waste acid belongs to Hazardous wastewater, cannot be used to treat printing and dyeing wastewater
[0003] The main method of the existing aluminum nitrate production technology is: use nitric acid and aluminum hydroxide or metal aluminum to synthesize aluminum nitrate. During the synthesis process, waste acid vapor will be generated, and the waste acid vapor needs to be reprocessed before it can be discharged. This synthesis method requires a lot of raw material input. ,higher cost

Method used

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  • Recycling method for electrode foil-corrosion waste nitric acid

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Experimental program
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Effect test

Embodiment 1

[0030] (1) Preheating: Send the filtered electrode foil waste acid to the feed tank, pressurized by the feed pump, enter the heat exchanger to preheat to about 63°C, and then heat to 82°C through the preheater , into the first-effect falling film evaporator; among them, the steam in the shell side of the first-effect and third-stage falling-film evaporators is mixed with non-condensable gas as the preheating heat source;

[0031] (2), evaporation:

[0032] One-effect evaporation: pump the waste acid preheated in step (1) into the first-effect falling-film evaporator, the raw material in the tube of the first-effect falling-film evaporator exchanges heat with the heating steam outside the tube to make the raw material boil and evaporate, and the raw material is concentrated The pressure difference enters the two-effect falling film evaporator;

[0033] Among them, the water vapor generated by the evaporation of the second-effect falling film evaporator and the third-stage fall...

Embodiment 2

[0048] (1) Preheating: Send the filtered electrode foil waste acid to the feed tank, pressurized by the feed pump, enter the heat exchanger to preheat to 60°C, and then heat to 85°C through the preheater. After entering the first-effect falling film evaporator; among them, the steam in the shell side of the first-effect and third-stage falling-film evaporators is mixed with non-condensable gas as a preheating heat source;

[0049] (2), evaporation:

[0050] One-effect evaporation: pump the waste acid preheated in step (1) into the first-effect falling-film evaporator, the raw material in the tube of the first-effect falling-film evaporator exchanges heat with the heating steam outside the tube to make the raw material boil and evaporate, and the raw material is concentrated The pressure difference enters the two-effect falling film evaporator;

[0051] Among them, the water vapor generated by the evaporation of the second-effect falling film evaporator and the third-stage fal...

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Abstract

The invention belongs to the technical field of resource recycling and particularly relates to a recycling method for electrode foil-corrosion waste nitric acid. By virtue of organic combination of the steps of preheating, evaporative concentration, cooling crystallization, centrifugal separation and the like, nitric acid is effectively recycled, and a byproduct, namely aluminum nitrate, is obtained. Wastewater mainly contains nitric acid and aluminum nitrate, most moisture in the wastewater is removed through two-effect three-level MVR and single-effect evaporation, and a concentrated solution with high aluminum nitrate concentration is obtained; by carrying out cooling crystallization, aluminum nitrate with relatively low solubility can be separated for crystallization; and by carrying out solid-liquid separation, filtrate containing nitric acid and aluminum nitrate crystals can be effectively separated.

Description

technical field [0001] The invention belongs to the technical field of resource recovery, and in particular relates to a method for recycling waste nitric acid corroded by electrode foils. Background technique [0002] In the corrosion process of the electrode foil, the corrosion solution is mainly prepared by nitric acid in a certain proportion. Under certain temperature and current conditions, the aluminum foil is corroded, and then expanded by the nitric acid solution to become a semi-finished product of the formed foil (etched foil). , After chemical conversion, electrode foil (chemical conversion foil) is obtained. The corrosion and hole reaming process has high requirements on the components of the corrosion solution, so new solutions need to be added continuously, and the overflowed acid solution becomes waste acid. This waste acid not only contains a small amount of free sulfuric acid, but also contains aluminum ions corroded from the aluminum foil. The waste acid c...

Claims

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Application Information

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IPC IPC(8): C01F7/66C01B21/46C23F1/46
CPCC01B21/46C01F7/66C23F1/46
Inventor 徐晨姚洪齐
Owner 常州中源工程技术有限公司
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