Electronic grade hydrogen chloride purification method

Abstract

The invention provides an electronic grade hydrogen chloride purification method. The method is characterized by comprising the following steps: introducing industrial liquid hydrogen chloride with purity of 99% to the middle position of a first rectifying tower to be rectified so as to remove light components; introducing a liquid coming out from the bottom of a reboiler of the first rectifying tower to the middle position of a second rectifying tower by a pump to be rectified, condensing hydrogen chloride generated through heating by a second reboiler with a second condenser, controlling the reflux ratio, enabling part of hydrogen chloride to flow back to the second rectifying tower and transferring the other part of hydrogen chloride to middle storage tanks to be stored and pumping out residual liquid from the bottom of the second reboiler to a waste liquid storage tank so as to remove heavy components; and obtaining high-purity hydrogen chloride with purity above 99.9999% through adsorption and purification of at least an adsorption tower with a molecular sieve inside. The method has the effect of avoiding introduction of other impurity media, is simple to operate and is low in production cost.

Description

technical field [0001] The invention relates to a method for purifying electronic-grade hydrogen chloride, which belongs to the field of production and purification of electronic special gases. Background technique [0002] Electronic-grade hydrogen chloride is mainly used for high-temperature vapor phase etching of silicon and gallium arsenide before epitaxial growth to remove sodium ions. In addition, high-purity hydrogen chloride is also used for chemical treatment of metal surfaces, mixed gas for lasers, film production and carbon fiber surface treatment. Moreover, high-purity hydrogen chloride is used in the pharmaceutical, chemical, and semiconductor industries, so the demand is increasing. Most of my country's electronic-grade hydrogen chloride products are imported from the United States, Japan and other countries, which are expensive. Therefore, we need to further study and improve the synthesis process of electronic grade hydrogen chloride, which will bring certai...

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Problems solved by technology

[0003] At present, some researchers have successfully synthesized electronic-grade hydrogen chloride in the research and preparation process. At the same time, it has been found from these synthesis methods that the process of preparing hydrogen chloride by analytical method and hydrochloric acid desorption method is simple and can be produced on a large scale, but the purity of the prepared hydrogen chloride is relatively low. The less it meets the requirements of the electronics industry, especially integrated circuits

The purity of hydrogen chloride produced by synthetic method is relatively high, but the water content is high, the corrosion is serious, the requirements for equipment are high, and the production cost is high

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