A method for preparing an electronic-grade hydrogen fluoride washing and absorbing device

Abstract

The invention relates to the technical field of fluorine chemical engineering and particularly relates to an operation method of a washing and absorbing device for preparing electronic-grade hydrogenfluoride. The method is characterized in that tail gas is fed through a gas feeding duct, with the temperature of the tail gas at this time being 19-21 DEG C; the tail gas flows upward through a filler and a liquid distributing grid tray in the washing and absorbing column and is subjected to mass and heat transfer with a hydrofluoric acid condensate sprayed by a spraying pipe member; the cooled tail gas enters a tail gas inlet of a condensation column through a gas discharging duct, is subjected to heat transfer with a condensation tube plate, then passes through a liquid removing device andis discharged through a tail gas discharging port; the temperature of the tail gas discharging port is controlled to be 9-10 DEG C; the hydrofluoric acid condensate condensed in the washing and absorbing column is gathered by the filler, and flows through a liquid collection tube along the wall of the washing and absorbing column to a circulation storage tank; the hydrofluoric acid condensate condensed in the condensation column flows to the circulation storage tank through a condensate outlet; and a circulation pump assembly allows the hydrofluoric acid condensate in the circulation storage tank to return to the spraying pipe member and to wash condensation tail gas.

Description

technical field [0001] The invention relates to the technical field of fluorine chemical industry, in particular to a method for preparing an electronic-grade hydrogen fluoride washing and absorbing device. 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, inc...

AI Technical Summary

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

Images