Device and method for recycling aluminum etching solution

Abstract

The invention discloses a device and method for recovering and reusing aluminum etching solution. The device includes a waste acid storage tank, which is connected to a reactor feeding pipeline, and the reactor is also connected to a phosphorus pentoxide feeding pipeline; The outlet of the evaporator is connected to the evaporator, the outlet of the evaporator is connected to the evaporative separator, the gas outlet of the evaporative separator is connected to the exhaust gas condenser and the exhaust gas separator in turn, the liquid outlet of the evaporative separator is connected to the phosphoric acid stripping tower, and then connected to the phosphoric acid stripper in turn Reconcile the kettle and the phosphoric acid storage tank; the lower part of the phosphoric acid stripper is equipped with a nitrogen inlet pipe. The device and method of the present invention can effectively separate the phosphoric acid from the nitric acid and acetic acid in the waste aluminum etching solution, and the nitric acid and acetic acid can be recovered and reused to produce the etching solution, and industrial phosphoric acid of various concentrations can also be prepared according to the needs, making it waste For treasure.

Description

technical field [0001] The invention belongs to the field of electronic chemicals, and in particular relates to a device and method for recycling aluminum etching solution in a semiconductor factory. Background technique [0002] Aluminum etchant is a formula-type electronic chemical used to etch and remove panel aluminum or aluminum alloy in the TFT-LCD panel manufacturing process. Its main composition is phosphoric acid and a small amount of nitric acid, acetic acid, and additives. Aluminum etching solution will produce a large amount of waste liquid containing phosphoric acid, nitric acid, acetic acid and other impurities after use. Due to the high cost and difficulty of processing waste liquid containing phosphorus and acid, most semiconductor and panel manufacturers outsource the treatment. [0003] At present, domestic waste acid treatment methods mainly include: concentration method, neutralization method, roasting method, extraction method, ion exchange method, etc.,...

AI Technical Summary

Problems solved by technology

[0003] At present, domestic waste acid treatment methods mainly include: concentration method, neutralization method, roasting method, extraction method, ion exchange method, etc., none of which can effectively recycle waste acid and avoid the generation of waste

Not only increases the production cost of semiconductors and panels, but also the discharge of waste will have an impact on the environment

[0004] Chinese patent CN200510075397 proposes a method for purifying phosphoric acid by combining fractionation and esterification. First, the nitric acid is vaporized and separated, and the mixture of phosphoric acid and acetic acid is converted into acetate by ethanol esterification, thereby separating acetic acid and phosphoric acid. No waste liquid is generated, and phosphoric acid in the aluminum etching solution can be effectively separated. However, in the process of acetic acid separation, this method first adopts negative pressure distillation to separate most of the acetic acid, and then uses a small amount of acetic acid in ethanol and phosphoric acid to form acetate, which is separated Phosphoric acid, this process is not only complicated, but also reduces the concentration of phosphoric acid, and some ethanol will remain in phosphoric acid, affecting product quality

This method can completely separate phosphoric acid, acetic acid, and nitric acid, and no waste acid is produced, but this method is complex in process, and has low yield and high energy consumption in the process of phosphoric acid crystallization, melting and purification, and cannot be applied to industrial production on a large scale.

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