Hydrogen fluoride adsorbent and its preparation method and uses

Abstract

The selective hydrogen fluoride adsorbent is prepared with alkali metal fluoride, alkali earth metal fluoride and / or alkali metal fluorohydride, and through mixing, crushing into 50-120 mesh fine powder, mixing with silicon containing bauxite powder, alumino silica powder and / or water glass in 2-25 wt%, adding proper amount of water and blended into dough-like matter, extrusion to form, pelletizing and stoving. The adsorbent is suitable for adsorption of HF gas from mixed gas in the production of CFC, HCFC, HFC, SO2F2, etc with excessive HF as fluoridizer, and may reach a HF recovering rate as high as 95-99 %.

Description

technical field [0001] The present invention relates to a hydrogen fluoride adsorbent and its preparation method and application, especially in the preparation of chlorofluoroalkane (CFC), hydrochlorofluoroalkane (HCFC) and hydrofluoroalkane through fluorination reaction with excess hydrogen fluoride as fluorinating agent (HFC) and sulfuryl fluoride (SO 2 f 2 ) and other products, the selective adsorption, separation and recovery of hydrogen fluoride in the mixed gas of the reaction. Background of the invention [0002] Preparation and production of CFC, HCFC and HFC refrigerants, blowing agents and fumigants sulfuryl fluoride (SO 2 f 2 ) and other product processes, usually all use excess hydrogen fluoride as fluorinating agent, and the crude product of fluorination contains excess hydrogen fluoride, which must be separated and recycled. In the prior art, the by-product hydrochloric acid is usually produced by absorbing tail gas with water , and diss...

AI Technical Summary

Problems solved by technology

The recycling and use of a large amount of this fluorine-containing hydrochloric acid causes serious fluorine pollution

Compression, freezing, and distillation are also used to separate HF. This method requires high equipment and high energy consumption, and because hydrogen fluoride and fluorinated main and by-products will form azeotropes or azeotrope-like substances, this method is difficult to completely separate and recover hydrogen fluoride.

For this reason, the British Imperial Chemical Industries Company proposed a hydrogen fluoride adsorption separation method using alkali metal fluorides such as lithium fluoride, potassium fluoride, and cesium fluoride as adsorbents, namely WO 94 / 20412, GB [31] 9707176.5, CN 94191408 and the method mentioned in the CN 98804029.8 patent application, but these patent specifications do not have a clear and complete description of the adsorbent, and the operator cannot implement it in the application, and, with regard to the application data given by it, its absorption and separation effect is also not ideal

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