NaF-NaCl-BaF2-AIF3系溶融塩の密度と融点について
アルミニウムの電解精製に関する研究 (第6報)
1969 年 85 巻 969 号 p. 43-47
詳細
1969 年 85 巻 969 号 p. 43-47
It is reported that the Gadeau's bath is more suitable for the aluminum refining when a small amount of sodium chloride is added.
We expected that the addition of some amounts of sodium chloride to the Hoopes' bath (molten salts of sod ium fluoride-barium fluoride-aluminum fluoride system) would be also effective showing the lower melting points of this ternary molten salts as well as the increase of its electric conductivities.
In this paper, the densities and the melting, temperatures of some compositions of the quaternary molten salts, sodium fluoride-sodium chloride-barium fluoride-aluminum fluoride system, were determined.
1) The values of the densities of this quaternary system ranged 2.2-2.9g/cc at 950°C. These values increased with the increase in the content of barium fluoride and decreased with the increase of sodium chloride.
When the content of sodium chloride and barium fluoride is kept constant, the maximum density isobserved at the point where the mol ratio of sodium fluoride andaluminum fluoride corresponds to (3: 1)(3NaF EA1F3)
2) In this quaternary system, the compound NaBaAlF6 is assumed to have been formed.
Calculated densities, assuming the additivity of the density of each salt and the formationof compound Na-BaAlF6 accord well with measured ones.
3) Isothermal liquidus line of this quaternry system has a likeness to that of sodium fluoride-barium fluoride-aluminum fluoride ternary system when the content of sodium chloride is kept, constant, but the melting temperatures are lower than the latter on the whole.
And the melting temperatures of two composition ranges are about 750°C.
4) We think that we can use various compositions of this quaternary molten salts as an electrolyte of aluminum refining as far as densities and melting temperatures are concerned.
