A kind of purification method of anhydrous hydrofluoric acid

Abstract

The invention relates to an anhydrous hydrofluoric acid purification method. The method comprises the following steps that 1, a crude hydrogen fluoride gas is subjected to washing aid washing, moisture, sulfuric acid and dust are removed, and a primary hydrogen fluoride gas is obtained; 2, after the primary hydrogen fluoride gas obtained in the first step is subjected to primary condensation, crude acid is separated out, and a secondary hydrogen fluoride gas is obtained; 3, the hydrogen fluoride gas obtained in the second step enters a purification tower, reboiling and secondary condensation are conducted, tail gas which is not condensed and high-boiling-point residual acid are separated out, and liquid hydrogen fluoride is obtained; 4, the liquid hydrogen fluoride obtained in the third step is detected to be qualified, and then anhydrous hydrofluoric acid is obtained. According to the method, the crude product quality of anhydrous hydrofluoric acid can be guaranteed, and meanwhile energy consumption can be reduced.

Description

technical field [0001] The invention relates to a method for purifying anhydrous hydrofluoric acid, belonging to the technical field of anhydrous hydrofluoric acid preparation. Background technique [0002] Anhydrous hydrofluoric acid is anhydrous hydrogen fluoride, and is a chemical product with a wide range of uses. The appearance is more than 99% of the colorless fuming liquid hydrofluoric acid, which is easy to gasify under reduced pressure or high temperature. It is mainly used to prepare fluorine salts, fluorohaloalkanes, fluorine refrigerants, corrode glass, impregnate wood, electrolyze elemental fluorine, etc. Anhydrous hydrofluoric acid has very active chemical properties and strong corrosiveness. , oxides, and silicates. [0003] The traditional production process of anhydrous hydrofluoric acid is to use sulfuric acid and fluorite to react to obtain crude hydrogen fluoride gas, which contains more dust, silicon fluoride, sulfur dioxide, sulfuric acid, water and ot...

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Problems solved by technology

[0003] The traditional production process of anhydrous hydrofluoric acid is to use sulfuric acid and fluorite to react to obtain crude hydrogen fluoride gas, which contains more dust, silicon fluoride, sulfur dioxide, sulfuric acid, water and other impurities. In the later purification process, the crude hydrogen fluoride gas needs After multi-stage heating and condensation to separate high-boiling point components and non-condensable gases, hydrogen fluoride undergoes multiple phase changes during the heating and condensation process, which consumes a lot of energy

Invention patent 200710306506.5 discloses a production process of anhydrous hydrofluoric acid. In the separation and purification process of crude hydrogen fluoride in this method, the rectification tower adopts the gas phase feeding method, and the purification equipment adopts two parts: the rectification tower and the degassing tower , hydrogen fluoride circulates between the two towers in the form of liquid phase. On the one hand, due to the strong corrosion of liquid phase hydrogen fluoride, the anti-corrosion requirements for equipment are extremely high, resulting in high investment in equipment costs; on the other hand, hydrogen fluoride in this process is still experienced The multiple transitions between gas phase and liquid phase still have the problem of high energy consumption; moreover, this process uses fans or compressors to directly pressurize the hydrogen fluoride gas from the top of the washing tower into the rectification tower, and the large amount of water brought in All the acid and liquid enter the rectification tower, resulting in a large load on the rectification tower, and it is difficult to separate the heavy components in the hydrogen fluoride gas, and the product quality cannot be guaranteed

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