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GERMANIUM
Natural Abundance, Stable Isobars Ge70, 20.55%, Zn70 Ge72, 27.37%, Se74 Ge73, 7.67%, Se76 Ge74, 36.74% Ge76, 7.67% The only charge material which has been used in the separation of germanium isotopes is liquid germanium tetrachloride. Germanium tetrachloride of sufficient purity for use as charge material is obtained from commercial sources and supplied to the source from a style SE stainless steel container located outside the calutron vacuum chamber. The usual charge consists of 400 g GeCl4 . Unresolved germanium charge material is recovered on completion of the separation series. Source, receiver, and liner components are washed with dilute sulfuric acid, and the wash solution is filtered to remove any solids. These solids are digested in 50% sulfuric acid. After filtering, the solids are treated with 14 N ammonium hydroxide and 30% hydrogen peroxide. Following this treatment, the solids are filtered and discarded. The combined filtrates and washings are made basic with ammonium hydroxide and saturated with hydrogen sulfide. After filtering and washing the precipitate, which represents unwanted impurities, it is discarded. A sufficient amount of 1:1 sulfuric acid is added to the filtrate to make it 6 N sulfuric acid. As the solution is acidified, white germanium disulfide precipitates. Additional hydrogen sulfide is passed through the solution to ensure complete precipitation, the solution is filtered through a Buchner funnel, and the precipitate is washed and damp dried. The germanium disulfide is then dissolved in concentrated ammonium hydroxide, and germanium dioxide is precipitated by the addition of hydrogen peroxide. Since this precipitation is not always complete, it is necessary to check the filtrate for germanium by the use of tannin. Ten grams of ammonium sulfate is added to 200 ml of the filtrate and the mixture boiled. To this is added 25 ml of a freshly prepared 5% tannin solution. After digesting for approximately 1 hr, any precipitated germanium is filtered, washed, dried, and carefully ignited to the oxide at 750ºC. Germanium and its compounds, with the exception of germane, are not considered toxic. |
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