Sodium hexafluoroaluminate
Encyclopedia
Sodium hexafluoroaluminate is the inorganic compound
with the formula
Na3
Al
F6
. This colourless solid, which occurs naturally as the mineral cryolite
, is used extensively in the industrial production of aluminium.
, and sodium hydroxide or the equivalent reagent hexafluorosilicic acid:
(or flux) for electrolysis aluminium oxides such as bauxite
. The conversion of aluminium oxides into metallic aluminium requires that the metal ions be dissolved so that they can accept the electrons provided in the electrolysis cell. A mixture of cryolite and some aluminium trifluoride is that solvent. Unlike typical solutions, this one requires temperatures approaching 1000 °C to melt.
Sodium hexafluoroaluminate is also used as a pesticide. Other uses include a whitener for enamels and an opacifier for glass.
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
Na3
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
Al
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
F6
Fluorine
Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...
. This colourless solid, which occurs naturally as the mineral cryolite
Cryolite
Cryolite is an uncommon mineral identified with the once large deposit at Ivigtût on the west coast of Greenland, depleted by 1987....
, is used extensively in the industrial production of aluminium.
History
In 1957, sodium hexafluoroaluminate was registered as a pesticide with the United States EPA. Today there are four Sodium hexafluoroaluminate products registered.Production
Most cryolite is manufactured from aluminium oxides, hydrofluoric acidHydrofluoric acid
Hydrofluoric acid is a solution of hydrogen fluoride in water. It is a valued source of fluorine and is the precursor to numerous pharmaceuticals such as fluoxetine and diverse materials such as PTFE ....
, and sodium hydroxide or the equivalent reagent hexafluorosilicic acid:
- 6 NaOH + Al2O3 + 12 HF → 2 Na3AlF6 + 9 H2O
Use
The main application of synthetic cryolite is as a solventSolvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
(or flux) for electrolysis aluminium oxides such as bauxite
Bauxite
Bauxite is an aluminium ore and is the main source of aluminium. This form of rock consists mostly of the minerals gibbsite Al3, boehmite γ-AlO, and diaspore α-AlO, in a mixture with the two iron oxides goethite and hematite, the clay mineral kaolinite, and small amounts of anatase TiO2...
. The conversion of aluminium oxides into metallic aluminium requires that the metal ions be dissolved so that they can accept the electrons provided in the electrolysis cell. A mixture of cryolite and some aluminium trifluoride is that solvent. Unlike typical solutions, this one requires temperatures approaching 1000 °C to melt.
Sodium hexafluoroaluminate is also used as a pesticide. Other uses include a whitener for enamels and an opacifier for glass.