| 摘要 |
<p>1439907 Lithium hexafluoroarsenate USS ENGS & CONSULTANTS Inc 13 Aug 1974 [16 Aug 1973] 35645/74 Heading C1A Lithium hexafluoroarsenate, which may be prepared by the neutralization of hexafluoroarsenic acid with lithium hydroxide, is purified by maintaining an aqueous solution of the impure material at 80-100‹ C. while adding lithium hydroxide to maintain the pH at least at 10À5 and until the consumption of the hydroxide is less than 0À5 millimoles/litre of solution/day thus converting the impurities into water insoluble compounds, e.g. lithium fluoride and lithium arsenate; the pH of the solution is then adjusted to within the range 7À5 to 9À0 by adding aqueous hydrofluoric acid and thence storing the hot solution to complete impurity precipitation and filtering the precipitate from the solution, cooling the filtrate to 0-25‹ C. to precipitate lithium hexafluoroarsenate trihydrate, and dehydrating the trihydrate at a temperature not exceeding 100‹ C. at least partially under reduced pressure with a dry gas sweep, e.g. with nitrogen, to give purified product.</p> |
