Preparation method of sodium fluoride

Abstract

The invention discloses a preparation method of sodium fluoride. The preparation method comprises the following steps: adding sodium sulfate solution at the mass percentage concentration of 12 to 28 percent into ammonium fluoride solution at the temperature of between 30 and 65 DEG C to generate sodium sulfate precipitate, wherein the ammonium fluoride at the mass percentage concentration of 8 to 50 percent serves as a raw material and the adding speed of the sodium sulfate is 40 to 200 ml / min; reacting for 60 to 130 minutes by controlling the stirring speed to 130 to 400 r / min; performing solid liquid separation to obtain sodium sulfate filter cakes; washing the filter cakes by using deionized water; and drying to obtain the sodium sulfate products. Compared with the prior art, the method has the advantages of using the sodium sulfate as the raw material instead of the conventional sodium chloride, preventing chloride ions from entering a production system, reducing corrosion-resistant requirement of the equipment and saving production cost. The method is simple and practical in process route and provides technological theory support for production of the sodium fluoride in the fluorine chemical industry enterprises.

Description

technical field [0001] The invention belongs to the field of fluorine chemical industry, and in particular relates to a preparation method of sodium fluoride. Background technique [0002] Sodium fluoride is a kind of fluorine chemical product widely used in the fluorine chemical industry. Sodium fluoride is a colorless shiny crystal or white powder, with a specific gravity of 2.25, a melting point of 993°C and a boiling point of 1695°C. Soluble in water and hydrofluoric acid, slightly soluble in alcohol. The aqueous solution is weakly alkaline and can be dissolved in hydrofluoric acid to form sodium bifluoride, which can corrode glass. [0003] Sodium fluoride is mainly used as a phosphating accelerator in the coating industry to stabilize the phosphating solution, refine the phosphating, and improve the performance of the phosphating film. In the phosphating of aluminum and its alloys, Al3+, which is very harmful and negatively catalyzed, is sealed to make the phosphatin...

AI Technical Summary

Problems solved by technology

[0005] The existing technology mainly uses ammonium fluoride and sodium chloride as raw materials to produce sodium fluoride. Using sodium chloride as the raw material for production, chloride ions are introduced into the production system, which has extremely high requirements for anti-corrosion of production equipment. Chloride ions will be difficult to get out of the production process, which will adversely affect the supporting production line