| 摘要 |
<p>1489557 Metal recovery A BUMBALEK 18 Feb 1976 [10 Sept 1975] 6476/76 Heading ClA [Also in Division C7] Metals, particularly Au, Pa, Re, Rh, lanthanides, and natural radio-active isotopes of U, Th and Ra, are extracted by comminuting the meat and/or peel or skin of dried or raw fruit (preferably bananas), burning the fruit in an oxidizing atmosphere at 820-840‹ C., grinding the ashes so produced to a particle size below 40Á and processing the ashes to extract the elements. The method is particularly applicable to fruit grown on poor soil where the elements normally occurring in the fruit (Ca, Na, K, Mg, Fe) are replaced by the above metals. The recovery of the individual elements from the ashes is achieved by known methods, e.g. Au by treating with Cl 2 , and subsequently precipitating the gold chloride in solution, or by cyanide leaching; Pa by pentahalides; Rh by melting with KHSO 4 ; Re by means of potassium perrhenate, Th by reduction of ThO 2 , and Ra by conversion to an azide which is then decomposed.</p> |
