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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

Inactive Publication Date: 2014-05-28
OG KK +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Metals such as Si are mixed in the hydrofluoric acid-based waste liquid after etching, so it cannot be reused. The current situation is to neutralize the hydrofluoric acid-based waste liquid and then drain it (see Patent Document 1).

Method used

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  • 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
  • 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
  • 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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0172] For mixed acid waste liquid (containing hydrofluoric acid, hydrochloric acid and Si 4+ mixed acid waste liquid), using figure 1 The recovery device 1 of the shown structure implements Si as follows: 4+ Removal process, 1st distillation process, 2nd distillation process.

[0173] (Si 4+ removal process)

[0174] 300 g of the mixed acid waste liquid (the components and the content of each component are shown in Table 1) and 25 g of sodium chloride were put into the mixing tank 9, and then stirred and mixed for 24 hours using a stirring blade to obtain a mixed liquid.

[0175] Next, the mixed solution is put into a centrifuge (solid-liquid separator) 10 for centrifugation, and the mixed solution is separated into precipitates (containing Si 4+ ) and supernatant (remove Si 4+ mixed acid waste; no sediment). The obtained precipitate was 66 g, and the obtained supernatant was 258 g.

[0176] In addition, it was confirmed from the analysis results obtained by XRD (X-ray...

Embodiment 2

[0182] For mixed acid waste liquid (containing hydrofluoric acid, hydrochloric acid and Si 4+ mixed acid waste liquid), using figure 1 The recovery device 1 of the shown structure implements Si as follows: 4+ Removal process, 1st distillation process, 2nd distillation process.

[0183] (Si 4+ removal process)

[0184] In the mixing tank 9, 300 g of the mixed acid waste liquid (the content of the components and the content of each component are shown in Table 2) and 25 g of potassium fluoride were put into the mixing tank 9, and then stirred and mixed with a stirring blade for 24 hours to obtain a mixed solution.

[0185] Next, the mixed solution is put into a centrifuge (solid-liquid separator) 10 for centrifugation, and the mixed solution is separated into precipitates (containing Si 4+ ) and supernatant (remove Si 4+ mixed acid waste; no sediment). The obtained precipitate was 103 g, and the obtained supernatant was 222 g.

[0186] In addition, it was confirmed from t...

Embodiment 3

[0192]For mixed acid waste liquid (containing hydrofluoric acid, hydrochloric acid and Si 4+ mixed acid waste liquid), using figure 1 The recovery device 1 of the shown structure implements Si as follows: 4+ Removal process, 1st distillation process, 2nd distillation process.

[0193] (Si 4+ removal process)

[0194] 300 g of the mixed acid waste liquid (the contained components and the content of each component are shown in Table 3) and 18 g of sodium fluoride were put into the mixing tank 9, and then stirred and mixed for 24 hours using a stirring blade to obtain a mixed liquid.

[0195] Next, the mixed solution is put into a centrifuge (solid-liquid separator) 10 for centrifugation, and the mixed solution is separated into precipitates (containing Si 4+ ) and supernatant (remove Si 4+ mixed acid waste; no sediment). The obtained precipitate was 69 g, and the obtained supernatant was 248 g.

[0196] In addition, it was confirmed from the analysis results obtained by X...

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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.

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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Application Information

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IPC IPC(8): C02F1/60C01B7/19
CPCB01J19/24B01J19/2405C01B7/19
Inventor 山本秀树小野浩司小川薰
Owner OG KK
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