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Preparation method for ultra-pure nitric acid

A pure nitric acid, ultra-high technology, applied in the field of ultra-high-purity nitric acid preparation, can solve the problems of ultra-high-purity nitric acid with many impurities and insufficient purity, and achieve the effect of high purity and less impurities

Inactive Publication Date: 2014-11-26
JIANGYIN JIANGHUA MICROELECTRONICS MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

The current ultra-high-purity nitric acid used for ultra-large-scale integrated circuits has many impurities, and the purity is not enough

Method used

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Examples

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Embodiment Construction

[0011] The invention is described below by way of examples, but is not limited to the examples given.

[0012] (1) Electronic grade nitric acid is electrically heated and rectified, and the temperature is controlled at 110°C ± 10°C;

[0013] (2) the product obtained in step (1) is passed through a whitening reactor to remove nitrogen dioxide in the fraction with nitrogen, making it transparent and colorless;

[0014] (3) Put the product obtained in step (2) into a mixing tank, add an appropriate amount of ultrapure water, and stir for 30 minutes;

[0015] (4) the product obtained in step (3) is filtered through a filter of 0.2 μm to remove harmful particles with a particle diameter greater than 0.2 μm in the mixture to obtain this ultra-high-purity nitric acid;

[0016] The above-mentioned method for preparing ultra-high-purity nitric acid, wherein: the relative density of nitric acid in the step (1) is 1.40-1.42.

[0017] In the step (3), the concentration of nitric acid is...

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PUM

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Abstract

The invention discloses a preparation method for ultra-pure nitric acid. The method comprises the steps of: (1) subjecting electronic grade nitric acid to electric heating rectification, and controlling the temperature at 100-120DEG C; (2) employing nitrogen to remove nitrogen dioxide from the fraction obtained in step (1) by a bleaching reaction kettle to make the fraction colorless and transparent; (3) putting the product obtained in step (2) into a mixing tank, adding an appropriate amount of ultrapure water, and performing stirring for 30min; and (4) filtering the product obtained in step (3) by a 0.2micrometer filter to remove harmful particles with a particle size larger than 0.2 micrometer from the mixture, thus obtaining the nitric acid. According to the preparation method, under original production process conditions, through further rectification purification and precise mixing, impurities in the product can be removed, so that the nitric acid can have purity reaching the PPt grade, and can meet the production process requirement of ultra large scale integrated circuits.

Description

technical field [0001] The invention relates to a method for preparing nitric acid, in particular to a method for preparing ultra-high-purity nitric acid. Background technique [0002] In recent years, China's integrated circuit industry has expanded its industrial scale from low-end to high-end products to a new stage. At present, driven by the solar green energy industry around the world, my country's solar energy industry has developed rapidly. China has become The world's largest producer of photovoltaic products will enter a period of full-speed development in the future after the release of the "Renewable Energy Medium and Long-term Development Plan". The above situations indicate that my country is ushering in a new round of development in solar energy, IC, TFT-LCD and other industries. Its supporting reagents also ushered in new opportunities and challenges. The current ultra-high-purity nitric acid used for ultra-large-scale integrated circuits has many impurities, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/46
Inventor 殷福华朱龙邵勇
Owner JIANGYIN JIANGHUA MICROELECTRONICS MATERIAL
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