Continuous production method of high-purity hydrochloric acid

Abstract

The invention relates to a continuous production method of high-purity hydrochloric acid; the continuous production method is carried out by chemically dechlorinating, rectifying at normal pressure, filtering in a circulating manner, decompressing and rectifying by taking industrial hydrochloric acid as the raw material; in the event of decompressing and rectifying, the pressure in a decompressing and rectifying kettle is controlled within 25-95 KPa; the reflux ratio is 1:(1.8-2.5); and various processes in the process are carried out sequentially and continuously. According to the invention, high-purity hydrochloric acid achieving the SEMIC12 semiconductor grade requirements can be produced environmentally, efficiently and continuously through the four simple steps; in the obtained hydrochloric acid product, the content of single metal ion can be reduced to be below 50 ppt; the content of anion can be reduced to be below 50 ppb; and the content of free chlorine can be reduced to be below 300 ppb. An online control technology and a totally-enclosed purified production manner provided by the invention are further combined, therefore, hydrochloric acid products having steady quality can be produced reliably for a long time; and long-term, large-batch and steady specific requirements in the semiconductor industry are satisfied.

Description

technical field [0001] The invention relates to a preparation method of high-purity hydrochloric acid, especially electronic-grade high-purity hydrochloric acid. Background technique [0002] Ultra-clean and high-purity electronic chemicals are key integrated raw materials for VLSI manufacturing, and their purity and cleanliness have a very important impact on yield, electrical performance, and reliability. The current mainstream semiconductor technology has reached 0.09-0.2μm, the tip has reached the 22nm level, and the corresponding electronic chemicals have also reached the SEMIC12 requirements. The production technology of high-purity electronic chemicals is mastered by a few developed countries such as Germany, Japan and the United States. At present, my country can only produce primary and intermediate electronic chemicals. The purity of high-purity electronic chemicals is getting higher and higher, and the added value of products is greater. The R&D and technology o...

AI Technical Summary

Problems solved by technology

Using this process to prepare high-purity hydrochloric acid requires high equipment requirements and high risk, and the patent was applied for in 1996, and the relevant technical indicators can only reach the ppb level. Compared with the current SEMI12 requirements, it can no longer meet the production requirements.

In 2004, the Beijing Institute of Chemical Reagents also applied for a similar patent CN200410091153.8, but unfortunately the corresponding test results were not given in the patent, and corresponding clear comparisons could not be made

And the long-term, large-scale, stable, low-cost high-purity hydrochloric acid production control technology that is crucial to the semiconductor industry has not yet seen relevant public reports

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