GB1137037A - Process for the extraction and the concentration of hydrogen fluoride - Google Patents

Abstract

1,137,037. Hydrogen fluoride. PRODUITS CHIMIQUES PECHINEY - SAINT - GOBAIN. 10 March, 1967 [11 March, 1966], No. 11464/67. Heading C1A. [Also in Division C2] Hydrogen fluoride in the vapour phase is extracted from a gaseous mixture by a continuous process which comprises simultaneously introducing the gaseous mixture into one end of a counter-current extracting apparatus, introducing a current of a water-insoluble amine which is not combined with any hydrogen fluoride into the opposite end of the apparatus, and introducing a current of the same amine partially combined with hydrogen fluoride into an intermediate part of the apparatus whereby the amine takes up hydrogen fluoride from the gaseous mixture, and part of the resulting current of hydrogen fluoride-combined amine is treated with an acid thus liberating HF and precipitating a compound of said acid with said amine, the uncombined amine is recovered from the said precipitated compound (e.g. by NaOH solution) and passed back to the opposite end of the counter-current apparatus, the remaining current of amine combined with HF is passed to a desorption apparatus which is maintained at a temperature just sufficient to cause part of the HF to separate from the current of amine containing it, the resultant amine partially combined with HF is passed back to the intermediate part of the counter-current absorption apparatus. The desorption apparatus is maintained at a temperature not exceeding 200‹ C. Amines which may be used include N-lauryl (trialkylmethyl) amines, trioctylamines, trinonylamines and trilaurylamines, and can be regenerated during the process with H 2 SO 4 or H 2 SiF 6 acid.