アルミニウムの精製に関する研究
NaF-BaCl2-AlF3系電解浴の密度について
1967 年 83 巻 949 号 p. 765-769
詳細
1967 年 83 巻 949 号 p. 765-769
The molten salts, sodium fluoride-barium chloride-aluminum fluoride system, are known as “Gadeau's bath” for the electrolytic refining of aluminum. The melting points of this system were reported by one of the authors.
In this study, the densities of some compositions of the above mentioned molten salts which show low melting points (700°C-850°C) were determined using a platinum sinker suspended with a fine platinum wire from a balance.
Following results were obtained;
1) The densities of molten salts were ranged from 2.3g/cc to 2.8g/cc at 850°C. The densities increase with the content of barium chloride.
2) In the binary system, sodium fluoride-barium chloride, the following displacement reaction occurs. NaF-I-BaCl2=NaCl+ BaFCl
3) When the content of barium chloride is kept constant, the maximum density is observed at the point where the mol ratio of sodium fluoride and aluminum fluoride corresponds to 3: 1 (3NaF. AIF3) after the displacement reaction has occurred.
4) Calculated densities, assuming the additivity of the density of each salt, accord well with measured ones.
5) In this system, the following compositions show lower melting points and the densities which are suitable for the molten electrolyte of the refining of aluminum; sodium fluoride 10-40%, barium chloride 50-70%, aluminum fluoride 5-25%.
