Method for preparing potassium fluoride from crude potassium bifluoride

Abstract

The invention relates to a method for preparing potassium fluoride from crude potassium bifluoride, and belongs to the technical field of fine chemical engineering. The method comprises the followingsteps: drying the crude potassium bifluoride while stirring; adding water into the dried crude potassium bifluoride to prepare turbid liquid; dropwise adding an alkaline solution into the turbid liquid while stirring for reaction, and ending the reaction when the pH value of the solution is 9-10.5; and carrying out spray drying on the reacted solution to obtain a potassium fluoride product. The crude potassium bifluoride is composed of potassium bifluoride, potassium fluoride and an organic solvent, wherein the mass fraction of potassium fluoride is less than or equal to 5%, and the mass fraction of the organic solvent is less than or equal to 2%. The method is simple in process, greatly reduces the production cost and is easy to popularize.

Description

technical field [0001] The invention relates to a method for preparing potassium fluoride by utilizing crude potassium hydrogen fluoride, belonging to the technical field of fine chemicals. Background technique [0002] Potassium fluoride is the main source of fluoride ions except hydrogen fluoride. It belongs to alkali metal halides. Its aqueous solution will corrode glass and form soluble fluorosilicate. It can also be used as an absorbent for hydrogen fluoride and water, and it is also used for the preparation of potassium hydrogen fluoride. raw materials. Potassium fluoride is stable in nature, and only a small amount of decomposition will occur when heated to the sublimation temperature. Due to the advantages of small volume, large electronegativity and high electron cloud density of fluorine atoms, fluorine-containing compounds have many special properties and are widely used as synthetic fluorinating agents for medicines, pesticides, dye intermediates and fine chemic...

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Problems solved by technology

[0005] Chinese patent application 201410308680.3 discloses a method of using fluosilicic acid to prepare potassium fluoride to co-produce white carbon black. The method is easy to mix more silicon dioxide in potassium fluoride, resulting in the index of potassium fluoride not reaching the target National standard

Chinese patent application 201410094916.8 discloses a method for preparing potassium fluoride using fluorine in the liquid phase of wet-process phosphoric acid. The method uses fluorine in the liquid phase of wet-process phosphoric acid to prepare potassium fluoride. There are also differences in product purity and When the activity is difficult to meet the requirements

Chinese patent application 201410064707.9 discloses a method for producing high-purity potassium fluoride by using hydrofluoric acid raffinate; the potassium fluoride produced by the method contains impurities such as sodium fluoride. Although the utilization rate of fluorine is high, the fluoride The purity of potassium will affect the activity and application of potassium fluoride

Potassium hydrogen fluoride produced by this process contains a small amount of organic solvent and cannot be used directly as potassium hydrogen fluoride

Moreover, potassium bifluoride is easy to harden during the production process, and the activity of potassium fluoride obtained after direct heating to remove hydrogen fluoride is greatly reduced, which cannot meet the activity requirements for potassium fluoride

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