A method of using a process device for preparing electronic grade hydrogen fluoride

Abstract

The invention relates to the technical field of fluorine chemical engineering, in particular to an application method for preparing an electronic grade hydrogen fluoride process device. The method ischaracterized in that high-boiling residues HAsF6 and MAsF6 are produced through arsenic impurity in fluorine oxidized hydrogen fluoride, and the pure electronic grade hydrogen fluoride is separated from a multi-component composition through volatility difference of the high-boiling residues HAsF6 and MAsF6, HF and other components and multiple equilibrium processes. A rectification technical process adopts reflux liquid and upward gas to form gas and liquid countercurrent contact in a distillation tower, volatile component products with high purity can be obtained from the top of the tower, and non-volatile component products with high purity can be obtained from the bottom of the tower. The main component of tail gas produced from hydrogen fluoride rectification mainly comprises HF steam, the tail gas further comprises the following volatile components: SO2, SiF4, PF3, POF3, AsF5, SF6 and PF5, and the tail gas can be completely washed with pure water, condensed and recycled to prepare technical grade hydrofluoric acid.

Description

Technical field [0001] The invention relates to the technical field of fluorine chemicals, in particular to a method of using a process device for preparing 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 for these industries. Because the impurity arsenic has a serious impact on the performance of electronic devices, the removal of arsenic is the purification of hydrogen fluoride The key technology, the usual method is to use an oxidant to oxidize trivalent arsenic into 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 t...

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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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