Device and method for recycling aluminum etching solution

Abstract

The invention discloses a device and method for recycling an aluminum etching solution. The device comprises a waste acid storage tank, wherein the waste acid storage tank is connected to a feeding pipeline of a reaction kettle; the reaction kettle is also connected with a phosphorus pentoxide feeding pipeline; a discharge hole of the reaction kettle is connected to an evaporator; a discharge holeof the evaporator is connected to an evaporation separator; a gas outlet of the evaporation separator is sequentially connected with an exhaust gas condenser and an exhaust gas separator; a liquid outlet of the evaporation separator is connected to a phosphoric acid stripping tower and then is sequentially connected with a phosphoric acid blending kettle and a phosphoric acid storage tank; and anitrogen introducing pipeline is arranged on the lower part of the phosphoric acid stripping tower. By adopting the device and method disclosed by the invention, phosphoric acid in the waste aluminumetching solution can be effectively separated from nitric acid and acetic acid, the nitric acid and the acetic acid can be recycled for producing the etching solution, and industrial phosphoric acid of various concentrations can be blended according to the requirements, so that the waste is changed into valuable.

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.,...

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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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