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Semiconductor waste acid treatment method

A treatment method and semiconductor technology, which is applied in the treatment of waste acid and semiconductor waste acid, can solve the problems of increased difficulty and complicated process, and achieve the goals of reducing acid consumption, improving economic benefits, and reducing acid consumption Effect

Inactive Publication Date: 2020-08-25
盛隆资源再生(无锡)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The technological process is relatively complicated and requires the use of a large amount of capture agent, which increases the difficulty of subsequent treatment

Method used

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  • Semiconductor waste acid treatment method

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Effect test

Embodiment 1

[0043] This embodiment provides a treatment method for semiconductor waste acid, the process flow diagram of the treatment method is as follows figure 1 shown, including the following steps:

[0044] (1) Sodium nitrate is added in the semiconductor waste acid to cause precipitation in the semiconductor waste acid, and after the precipitation is complete, filter and separate to obtain sodium fluorosilicate precipitation and filtrate; the semiconductor waste acid is composed of nitric acid, hydrofluoric acid and fluorosilicic acid The mixed waste acid of composition, the concentration of nitric acid in semiconductor waste acid is 20wt%, the concentration of hydrofluoric acid in semiconductor waste acid is 16wt%, the concentration of fluosilicic acid in semiconductor waste acid is 6wt%; In sodium nitrate, sodium ion and semiconductor The molar ratio of fluorosilicate ion in waste acid is 2:1;

[0045] (2) distillation purification step (1) gained filtrate, the temperature of dis...

Embodiment 2

[0049] The present embodiment provides a kind of processing method of semiconductor waste acid, and described processing method comprises the following steps:

[0050] (1) Sodium nitrate is added in the semiconductor waste acid to cause precipitation in the semiconductor waste acid, and after the precipitation is complete, filter and separate to obtain sodium fluorosilicate precipitation and filtrate; the semiconductor waste acid is composed of nitric acid, hydrofluoric acid and fluorosilicic acid The mixed waste acid of composition, the concentration of nitric acid in semiconductor waste acid is 15wt%, the concentration of hydrofluoric acid in semiconductor waste acid is 21wt%, the concentration of fluosilicic acid in semiconductor waste acid is 5wt%; In sodium nitrate, sodium ion and semiconductor The molar ratio of fluorosilicate ion in waste acid is 2.1:1;

[0051] (2) distillation purification step (1) gained filtrate, the temperature of distillation is 100 ℃, and vacuum ...

Embodiment 3

[0055] The present embodiment provides a kind of processing method of semiconductor waste acid, and described processing method comprises the following steps:

[0056] (1) Sodium nitrate is added in the semiconductor waste acid to cause precipitation in the semiconductor waste acid, and after the precipitation is complete, filter and separate to obtain sodium fluorosilicate precipitation and filtrate; the semiconductor waste acid is composed of nitric acid, hydrofluoric acid and fluorosilicic acid The mixed waste acid of composition, the concentration of nitric acid in semiconductor waste acid is 5wt%, the concentration of hydrofluoric acid in semiconductor waste acid is 25wt%, the concentration of fluosilicic acid in semiconductor waste acid is 3wt%; In sodium nitrate, sodium ion and semiconductor The molar ratio of fluorosilicate ion in waste acid is 2.4:1;

[0057] (2) distillation purification step (1) gained filtrate, the temperature of distillation is 110 ℃, and vacuum t...

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Abstract

The invention relates to a semiconductor waste acid treatment method, which comprises: (1) adding a sodium salt to semiconductor waste acid to produce a precipitate in the semiconductor waste acid, and carrying out solid-liquid separation after complete precipitation to obtain a sodium fluosilicate precipitate and a filtrate; (2) purifying the filtrate obtained in the step (1) to obtain a mixed acid solution and solid residues; and (3) carrying out concentration treatment on the mixed acid solution obtained in the step (2) to obtain a purified acid solution. Fluosilicic acid and impurities inthe semiconductor waste acid can influence the recycling of the semiconductor waste acid; according to the invention, fluosilicic acid in the semiconductor waste acid is firstly removed by utilizing the sodium salt, and then the purification treatment of the semiconductor waste acid can be realized by utilizing simple purification operation, so that the obtained purified acid liquid can be used for semiconductor etching, the consumption of acid in the semiconductor etching process is reduced, and the economic benefits of enterprises are improved.

Description

technical field [0001] The invention belongs to the technical field of waste liquid treatment, and relates to a treatment method of waste acid, in particular to a treatment method of semiconductor waste acid. Background technique [0002] The hydrofluoric acid etching process in the semiconductor field is mainly used in the etching of silicon and silicon dioxide. The discharged waste acid is mainly compounds such as fluosilicic acid, hydrofluoric acid and its mixed acids. If the waste acid is discharged directly, it will It causes environmental pollution and waste of valuable components, and does not meet the requirements of environmental protection. Therefore, it is necessary to treat the waste acid. [0003] The conventional neutralization method is to neutralize the pickling waste liquid to neutrality, and then dilute and discharge it. This treatment method cannot make full use of the useful components in the pickling waste liquid, resulting in a large waste of energy; H...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/10C01B7/19C01B21/46C02F103/34C02F101/14
CPCC02F9/00C01B7/195C01B7/196C01B21/46C02F2001/007C02F1/583C02F1/38C02F1/001C02F1/04C02F1/442C02F1/02C02F2103/346C02F2101/14
Inventor 郎超
Owner 盛隆资源再生(无锡)有限公司