Electron-grade hydrogen fluoride preparation procedure

Abstract

The invention relates to the technical field of fluorine chemicals and in particular relates to electron-grade hydrogen fluoride preparation procedures which are characterized by comprising an evaporation circulation oxidation reaction procedure, a circulating fluidized bed distillation procedure and a washing, absorption and condensation procedure.

Description

technical field [0001] The invention relates to the technical field of fluorine chemical industry, in particular to a preparation process of electronic-grade hydrogen fluoride. Background technique [0002] Electronic-grade hydrogen fluoride is mainly used as a cleaning agent and etchant in photovoltaics, integrated circuits and other industries. It is one of the key auxiliary materials in these industries. Since the impurity arsenic has a serious impact on the performance of electronic devices, the removal of arsenic is a must for the purification of hydrogen fluoride. The key technology is to use an oxidant to oxidize trivalent arsenic to a high-boiling pentavalent arsenic compound, and then use the difference in volatility to distill it out. Chinese invention patent (patent number CN201110276860.4, patent name is a method for preparing electronic grade hydrofluoric acid) discloses a method for preparing electronic grade hydrofluoric acid, including the following steps: (1...

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Problems solved by technology

[0003] Prior art 1 uses fluorine gas as an oxidant to oxidize impurities in hydrogen fluoride, and removes high boiling substances such as HAsF by washing and rectifying methods 6 , MAsF 6 、H 2 SO 4 、H 2 O, H 2 SiF 6 、H 3 PO 4 etc. and volatile component SO 2 、SiF 4 、PF 3 、POF 3 , AsF 5 , SF 6 、PF 5 etc., the problems still to be solved are, first, fluorine gas is highly toxic, highly chemically active and strong oxidizing, and it is difficult to solve the sealing problem of existing conveying machinery such as circulating pumps, and serious safety accidents are likely to occur if leakage occurs; , the integration of rectification and washing in a rectification tower does not meet the technical specifications; prior art 2 points out that the impurity arsenic in hydrogen fluoride has a serious impact on the performance of electronic devices, and the removal of arsenic is a key technology for the purification of hydrogen fluoride. The method commonly used in the prior art is to use an oxidant to oxidize trivalent arsenic to a high-boiling point pentavalent arsenic compound, and then use distillation to remove it. The oxidant is usually potassium permanganate, hydrogen peroxide, potassium dichromate, etc. The problems to be solved are: first, the introduction of other impurities increases the difficulty and cost of subsequent treatment; second, the oxidation time is longer, generally reaching 6 to 48 hours, and the energy consumption is higher

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