Molecular formula：NH4F
Molecular weight：37.04
Dangerous goods number：UN2505
CAS：12125-01-8
Physical and chemical properties:
At temperature, it is white or colorless leaf or acicular crystal. After sublimation, hexagonal columnar crystal is obtained. It is easy to deliquize and slightly sour. Delixifying, toxic, median lethal dose (rat, abdominal cavity) 32mG/kG. Corrosive.
Density(water:1):1.0090
Solubility：Easily soluble in water, aqueous solution is acidic. Soluble in alcohol, insoluble in acetone and liquid ammonia. It is decomposed into ammonia and hydrogen fluoride when exposed to heat or hot water. Decomposition with acid releases corrosive hydrogen fluoride gas. Alkali releases irritating ammonia. It is subject to high thermal decomposition and produces toxic corrosive fumes. Harmful combustion products: hydrogen fluoride, ammonia, nitrogen oxides.
The use of ammonium fluoride
The solvent of beryllium metal from beryllium oxide and the surface treatment agent of silicon steel plate are used for the etching of titanium and silicon wafers. Oxidizing substances such as nitric acid or chromic anhydride need to be added to the etching solution for titanium to prevent the occurrence of hydrogen embrittlement. It is also used for the manufacture of ceramics, magnesium alloys, cleaning and descaling of boiler feed water system and steam generation system. And the acid treatment of oil field sand and stone, also used as alkylation, isomerization catalyst components. Used to extract rare elements.
Precautions for operation of ammonium fluoride
Closed operation to provide adequate local exhaust. Prevent the release of dust into the workshop air. Operators must be specially trained and strictly abide by the operating procedures. It is recommended that the operator wear a dust mask (full cover), a rubber cloth anti-poison jacket, and rubber gloves. Avoid producing dust. Avoid contact with acids and alkalis. Equipped with leak emergency treatment equipment. Empty containers may have harmful residues.
Storage precautions for ammonium fluoride
Stored in a cool, ventilated warehouse. Keep away from fire and heat. Keep out of direct sunlight. The package is sealed. It should be stored separately from acids, alkalis and edible chemicals, and should not be mixed. Storage areas should be equipped with suitable materials to contain leaks.
The method of removing impurity magnesium from electrolytic manganese system by fluorine mineral is as follows: ammonium fluoride solution is prepared by fluorine mineral; Then ammonium fluoride solution was added to electrolytic manganese anodic solution or qualified solution for reaction, and magnesium fluoride precipitation and electrolytic manganese anodic solution or qualified solution were obtained after separation of solid and liquid.
