A kind of processing method of waste etching solution

Abstract

The invention provides a method for treating waste etching solution, comprising the following steps: placing the waste etching solution in an electrolysis device for electrolysis, wherein the anode material of the electrolysis device is iron or iron alloy; after electrolysis, the anode is dissolved to generate ferrous phosphate , adding an oxidizing agent to the obtained ferrous phosphate solution, and then performing solid-liquid separation, washing, and drying to obtain ferric phosphate. The method for treating waste etching solution of the present invention prepares iron phosphate from waste etching solution, which is a hazardous waste, through an electrolytic process with no pollution and mild reaction conditions, and solves the problem that traditional waste etching solution treatment adopts distillation, The problems of low yield, high cost and high energy consumption in processes such as extraction, the processing method of the present invention is simple in process, low in energy consumption, good in treatment effect, fine in product particles, low in production cost, easy in industrialization, and high in product added value. High economic and environmental benefits.

Description

technical field [0001] The invention relates to the technical field of waste treatment, in particular to a method for treating waste etching liquid. Background technique [0002] Thin Film Transistor Liquid Crystal Display (TFT-LCD) has become the most widely used, fastest growing and largest investment display industry in the world. The waste etching solution is produced in the wet etching process of the TFL-LCD production process, in order to dissolve and remove the film surface that is not covered by the photoresist, and finally form a circuit board of a specific shape. [0003] Waste etching solution is also produced in the semiconductor manufacturing industry. It is a mixture of phosphoric acid, nitric acid and acetic acid in a certain proportion. It is a kind of hazardous waste. It is strongly acidic and corrosive, and direct contact with the surface of the human body will cause burns. If it is directly discharged into the environment, it contains a large amount of N ...

AI Technical Summary

Problems solved by technology

If it is directly discharged into the environment, it contains a large amount of N and P elements, which will cause eutrophication of water bodies and cause harm to aquatic animals and plants. It is difficult to dispose of it economically and effectively, so it is necessary to find a green, economical and effective method to recycle the waste etching solution

[0004] Disclosed in the prior art is a method for reclaiming phosphoric acid in waste aluminum etching solution. It utilizes the large difference in boiling point and volatility of phosphoric acid, nitric acid, and acetic acid, and uses distillation or vacuum distillation to combine phosphoric acid, nitric acid, and acetic acid. Separation, the recycling of the mixed acid solution is realized by methods such as concentration and crystallization. This method has the advantage of strong operability and can meet the needs of large-scale production, but it needs to consume a lot of heat, high energy consumption, maintenance of distillation equipment and It occupies a large area, the processing process is cumbersome and complicated, the output is low, and the product purity is not high

[0005] The prior art also discloses a method for recovering phosphoric acid by extraction, in which an extractant containing trialkyl phosphate is mixed with a mixed acid solution to achieve the purpose of extracting phosphoric acid, and the extract containing acetic acid and nitric acid is stripped, The extract can be recycled. The advantage of this method is that it can selectively realize the recovery of phosphoric acid in the mixed acid solution, but it will use a large amount of organic extractant, and the process is complicated when separating nitric acid and acetic acid. The remaining nitric acid and acetic acid have no If it is effectively treated, it will still cause environmental pollution, and the cost is high, the device occupies a large area, and it is difficult to deal with the remaining organic solvents in the end.

[0006] The current treatment methods for waste etching solution mostly use methods such as distillation, neutralization, extraction, regeneration, and crystallization. For example, Samsung and other large electronic companies currently mostly use extraction methods for treatment, and these methods often have high energy consumption. Low output, high cost, complicated process, difficult process control, etc.

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