High purity potassium tetrafluoroaluminate and method of making same
AssigneeThe S. A. Day Mfg. Co., Inc.
InventorHelmut Flor
Life of this patent
Estimating the term…
Abstract
An improved method of making high quality potassium tetrafluoroaluminate. Hydrofluoric acid is added to high purity aluminum metal powder to form aluminum fluoride in solution. Nitric acid is added to this solution whereby impurities in the solution dissolve into the nitric acid. Water is then added to the solution to precipitate from the solution solid aluminum fluoride with impurities removed therefrom. The aluminum fluoride is then milled in the presence of hydrofluoric acid and potassium hydroxide whereby the exposure thereto produces the high quality potassium tetrafluoroaluminate which may then be washed and dried.
Claims11
A method of making potassium tetrafluoroaluminate comprising the steps of:
- a. adding hydrofluoric acid to aluminum metal powder having a purity of at least about 99.7 percent to thereby form aluminum floride in solution;
- b. adding nitric acid to the solution whereby impurities in the solution dissolve into the nitric acid;
- c. adding water to the solution to thereby precipitate from the solution solid aluminum fluoride with impurities removed therefrom;
- and
- d. milling the aluminum fluoride in the presence of hydrofluoric acid and potassium hydroxide thereby forming potassium tetrafluoroaluminate.
A method of making potassium tetrafluoroaluminate having a purity of at least about 96 percent comprising the steps of:
- a. adding hydrofluoric acid to aluminum metal powder having a purity of at least about 99.7 percent in an amount in excess of the molar proportion for the formation of aluminum fluoride to thereby form aluminum fluoride in solution;
- b. adding nitric acid in an amount equal to between about 3 and 10 percent of the hydrofluoric acid to the solution whereby impurities in the solution dissolve into the nitric acid;
- c. adding water to the solution to thereby precipitate from the solution solid aluminum fluoride with impurities removed therefrom;
- d. washing the precipitated aluminum fluoride at least once with water;
- e. milling the aluminum fluoride in the presence of hydrofluoric acid and potassium hydroxide thereby forming potassium tetrafluoroaluminate;
- f. washing the potassium tetrafluoroaluminate in water;
- and
- g. drying the potassium tetrafluoroaluminate.
Potassium tetrafluoroaluminate having a purity of at least about 96 percent and made by a process comprising the steps of adding hydrofluoric acid to aluminum metal powder having a purity of at least about 99.7 percent to thereby form aluminum fluoride in solution, adding nitric acid to the solution whereby impurities in the solution dissolve into the nitric acid, adding water to the solution to thereby precipitate from the solution aluminum fluoride with impurities removed therefrom, and milling the aluminum fluoride in the presence of hydrofluoric acid and potassium hydroxide thereby forming potassium tetrafluoroaluminate.
Dependencies are inferred from the claim text.