Process and device for preparing anhydrous hydrogen fluoride by recovery method

Abstract

The invention discloses a process and device for preparing anhydrous hydrogen fluoride by a recovery method. The process comprises the steps of (1) enabling concentrated fluosilicic acid obtained after concentration, calcium fluoride powder and concentrated sulfuric acid to act together, decomposing fluosilicic acid into silicon tetrafluoride and hydrogen fluoride, obtaining dilute sulfuric acid at the same time, reacting calcium fluoride with dilute sulphuric acid to obtain hydrogen fluoride and calcium sulfate, and filtering calcium sulfate; and (2) distilling the mixed acid reaction liquid containing hydrogen fluoride in a distillation system to obtain crude hydrogen fluoride gas. The process and the device are high in comprehensive utilization degree of resources and small in three-waste discharge amount, other emissions are reasonably utilized except a small amount of waste gas and filtered waste water, and the process and the device conform to the national industrial policy of energy conservation and emission reduction and belong to an environment-friendly construction project; few devices and equipment are needed, the frame equipment is compact in arrangement, the space is fully utilized, and the occupied area is small; and the operation pressure of the process technology is low, and leakage and diffusion of harmful gas during operation are effectively prevented.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a process and a device for preparing anhydrous hydrogen fluoride through a recycling method. Background technique [0002] Hydrogen fluoride is the basis of modern fluorine chemical industry. Anhydrous hydrogen fluoride is the raw material for electrolytic production of elemental fluorine; in the chemical industry, it is widely used in the chemical industry to replace chlorine in halogenated hydrocarbons to produce chlorofluorocarbons, such as difluorodichloromethane (F12) and Difluorochloromethane (F22), etc.; in the petrochemical industry, as a liquid catalyst for the alkylation of aromatics and aliphatic compounds to produce high-octane gasoline. In the electronics industry, anhydrous hydrogen fluoride is used as a raw material for the electrolytic synthesis of nitrogen trifluoride, as an etchant in semiconductor manufacturing processes, etc. In addition, hydrogen fluoride is...

AI Technical Summary

Problems solved by technology

[0003] Existing methods for preparing hydrogen fluoride mainly include sulfuric acid method, ammonium fluorosilicate method, lime method, Bush method, flame hydrolysis method, etc. There are problems such as uneven reaction process, unstable reaction efficiency, difficult to handle products, easy pollution to the environment, complex equipment, and high cost.

Images