What should I do if my skin comes into contact with fluorosilicic acid? Properties and safety protection of fluorosilicic acid

[Alias]Silic acid, hydrofluorosilicic acid

［Molecular Formula］H2SiF6

[Properties]Fluosilicic acid is a colorless gas. It is unstable and easily decomposes into silicon tetrafluoride and hydrogen fluoride. The aqueous solution is a colorless and transparent fuming liquid with a relative density of 1.32 and a boiling point of 108.5°C. It has a pungent odor and is easily volatile. Anhydrous fluorosilicic acid cannot be produced from fluorosilicic acid, and the maximum concentration is 60.92%. The most stable composition is 13.3%. It does not decompose during distillation: when the concentrated fluorosilicic acid solution is cooled, it can precipitate colorless dihydrate fluorosilicic acid (H2SiF6·2H2O). Its melting point is 19°C, it can be freely miscible with water, and has disinfection properties. Can corrode glass, ceramics, lead and other metals and should be stored in iron, wax or plastic containers. Strongly corrosive to skin.

[Use]Preparation of sodium fluorosilicate, potassium fluorosilicate, zinc fluorosilicate, magnesium fluorosilicate, and fluorosilicate Basic raw materials of calcium phosphate, ammonium fluorosilicate, cryolite and other fluorosilicates and silicon tetrafluoride. Used for wood preservation, beer disinfection, metal plating and porcelain processing, etc. Also used in the manufacture of coatings, cement hardeners, etc.

[Brief preparation method]

①In industry, the acid hydrolysis method of silica powder is mainly used, which is obtained by dissolving silica powder in hydrofluoric acid and then undergoing acidolysis, filtration, and purification.

②Mix quartz powder, calcium fluoride and concentrated sulfuric acid and then heat them. It can also be obtained from the silicon tetrafluoride gas that escapes when phosphate rock is decomposed in a phosphate fertilizer plant and is absorbed by water.

[Safety and Protection]Fluorosilicic acid is a first-class inorganic acidic corrosive substance, and the hazard code number is 91036. Packed in polyethylene plastic barrels, each barrel has a net weight of 20kg or 25kg. There should be a “Corrosive Materials” or “Violent Poison” mark on the packaging. Store in a cool, ventilated place.

When the skin is stained with fluorosilicic acid, it should be washed immediately with plenty of water or 10% ammonium carbonate solution.