Method for removing Si from waste liquid of Si-containing hydrofluoric acid, method for recovering hydrofluoric acid from mixed acid waste liquid of Si-containing hydrofluoric acid, and recovery device

A hydrofluoric acid system, hydrofluoric acid technology, applied in chemical instruments and methods, fluorine/hydrogen fluoride, water/sludge/sewage treatment, etc., can solve problems such as inability to reuse
CN103818992AInactive Publication Date: 2014-05-28OG KK +1
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Patent Information

Authority / Receiving Office
CN Β· China
Current Assignee / Owner
OG KK
Publication Date
2014-05-28
Estimated Expiration
Not applicable Β· inactive patent

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Abstract

According to the present invention, a removing method comprises a following process of removing, after a salt is added to a waste liquid of Si-containing hydrofluoric acid, a precipitate generated due to the added salt. In such a way, a process for removing Si in the waste liquid is obtained. The salt is preferably selected from one or two or more salts from a fluoride metal salt and a chloride metal salt. The Si contained in waste liquid of the Si-containing hydrofluoric acid can be effectively reduced or removed by using the removing method.
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Description

technical field

[0001] The present invention relates to, for example, a method for removing Si from hydrofluoric acid-based waste liquid such as an etchant used for semiconductors, a recovery method and a recovery device for recovering hydrofluoric acid from hydrofluoric acid-based mixed acid waste liquid. Background technique

[0002] Conventionally, hydrofluoric acid-based solutions such as hydrofluoric acid-based aqueous solutions, hydrofluoric-hydrochloric acid-based aqueous solutions, and hydrofluoric-nitric acid-based aqueous solutions are used as etchant in semiconductor factories and the like. Since the etching function is lowered due to repeated etching, a large amount of hydrofluoric acid-based waste liquid is discharged from such a semiconductor factory. Since metals such as Si are mixed in the hydrofluoric acid-based waste liquid after etching, it cannot be reused. At present, the hydrofluoric acid-based waste liquid is neutralized and then drained (see Patent Do...

Claims

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