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Method for recycling waste aluminum etching solution

An aluminum etching and solution technology, applied in chemical instruments and methods, separation/purification of carboxylic acid compounds, inorganic chemistry, etc., can solve the problems of difficult effective separation by ordinary distillation methods, unstable heating of nitric acid, waste of resources and solid waste, etc. , to avoid waste of resources and environmental pollution, improve rectification processing capacity, and improve economic benefits

Pending Publication Date: 2020-11-20
湖北兴福电子材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The boiling point of nitric acid is 83°C, and it is easy to form an azeotropic system with water.
Phosphoric acid has a boiling point of 261°C, while nitric acid is unstable when heated, and easily decomposes into brown-yellow gas NO, NO after exceeding 120°C 2 , direct discharge will cause harm to the environment
[0004] At present, the treatment method for waste aluminum etching solution is mainly acid-base neutralization treatment. The cost and energy consumption of this method are very high, which wastes a lot of resources and produces a large amount of solid waste (salts produced by acid-base neutralization)

Method used

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  • Method for recycling waste aluminum etching solution
  • Method for recycling waste aluminum etching solution

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Get waste aluminum etching solution 1000g, its main chemical composition and content are as follows:

[0022] chemical composition H3PO4 HNO3 CH3COOH H2O Content (mass fraction) 69.6％ 4.9％ 10.3％ 15.2％

[0023] Follow the steps below to recycle the waste aluminum etching solution:

[0024] (1) Add the waste aluminum etching solution to the tower kettle, turn on the vacuum pump to adjust the vacuum degree to 0.1MPa, start to heat slowly at a stirring speed of 100rpm, and control the temperature at about 100°C, due to the boiling points of phosphoric acid, nitric acid, and acetic acid The volatility is very different. The mixed acid of nitric acid and acetic acid was separated from the waste aluminum etching solution by fractional distillation, and 229.67g of distillate was collected, and 767.54g of tower bottom liquid was collected. After testing, the phosphoric acid content in the tower bottom liquid is about 90.6%.

[0025] (2) The main ...

Embodiment 2

[0031] Get waste aluminum etching solution 1000g, its main chemical composition and content are as follows:

[0032] chemical composition H3PO4 HNO3 CH3COOH H2O Content (mass fraction) 50.8％ 10.3％ 15.9％ 23.0％

[0033] According to the following steps, the mixed acid in the waste aluminum etching solution is recycled:

[0034] (1) Add 1000g of waste aluminum etching solution to the tower kettle, turn on the vacuum pump to adjust the vacuum degree to 0.1MPa, slowly heat and distill at a stirring speed of 100rpm, and control the temperature at about 120°C for 2 hours, due to phosphoric acid and nitric acid, acetic acid The boiling point and volatility of the distillate are very different. The nitric acid and acetic acid mixed solution was separated from the waste aluminum etching solution by fractional distillation, and 437.35g of distillate and 559.23g of tower bottom liquid were collected. After testing, the content of phosphoric acid in the towe...

Embodiment 3

[0042] Get waste aluminum etching solution 1000g, its main chemical composition and content are as follows:

[0043] chemical composition H3PO4 HNO3 CH3COOH H2O Content (mass fraction) 69.2％ 4.6％ 10.5％ 15.7％

[0044] According to the following steps, the mixed acid in the waste aluminum etching solution is recycled:

[0045] (1) Add 1000g of waste aluminum etching solution to the tower kettle, turn on the vacuum pump to adjust the vacuum degree to 0.1MPa, slowly heat and distill at a stirring speed of 100rpm, and control the temperature at about 120°C for 2 hours, due to phosphoric acid and nitric acid, acetic acid The boiling point and volatility of the distillate are very different. The nitric acid and acetic acid mixed solution was separated from the waste aluminum etching solution by fractional distillation, and 226.18g of distillate and 771.43g of tower bottom liquid were collected. After testing, the phosphoric acid content in the tower bo...

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Abstract

The invention relates to a method for recycling a waste aluminum etching solution, which comprises the following steps of: separating phosphoric acid from other components by adopting a reduced pressure distillation method to obtain a phosphoric acid solution with the concentration of over 90 percent and a mixed acid solution of nitric acid and acetic acid; when acid and water are separated from the mixed acid solution of nitric acid and acetic acid in a rectification mode, adopting the nitric acid, acetic acid and water to easily form an azeotropic system, enabling most of water serving as alight component to be concentrated at a tower top after rectification, and leaving nitric acid and acetic acid in a tower kettle; through continuous feeding, discharging light-component water from thetower top, and after the concentration of a tower kettle mixed acid solution reaches 70%, discharging the light-component water continuously, so that continuous rectification operation can be realized. According to the process, the waste aluminum etching solution containing various acids can be recycled, the phosphoric acid solution and the nitric acid and acetic acid mixed acid solution capableof being used for preparing the fresh aluminum etching liquid are obtained respectively, the consumption of acid is greatly reduced, solid waste generated by waste acid treatment is greatly reduced, and a new method is provided for recycling the aluminum etching liquid.

Description

technical field [0001] The invention relates to a recycling technology of waste acid liquid, in particular to a method for recycling waste aluminum etching liquid. Background technique [0002] In the manufacturing process of thin film transistor liquid crystal display (TFT-LCD), a large amount of acidic etching waste liquid will be generated during the etching process. If these waste liquids are not handled properly, it will not only cause waste of data, but also cause pollution to the ecological environment. Seriously affect human health. [0003] The waste aluminum etching solution is the waste liquid produced after wet etching the aluminum template in the TFT-LCD industry. Its main components are a mixture of phosphoric acid, nitric acid and acetic acid. The content is 4.0-28%, the content of acetic acid is 9-35%, and the content of water is 10-35%. , and a small amount of heavy metal impurities (AL, Mo), etc. Due to the complex composition of waste aluminum etching s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/237C01B21/46C07C51/42C07C51/44C07C53/08
CPCC01B25/237C01B21/46C07C51/42C07C51/44C07C53/08
Inventor 蔡步林杨着李少平郝晓斌贺兆波张庭陈建项扶伟毛志鹏
Owner 湖北兴福电子材料股份有限公司
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