Abstract
Plutonium is extracted by thenoyltrifluoroacetone and americium is isolated from the residue. Excess sodium hydroxide redissolves aluminum hydroxide while coprecipitating americium on lanthanum hydroxide. Trivalent americium is oxidized to the hexivalent americyl ion which is stabilized by the addition of ammonium fluoride. After reduction to the trivalent state, the purified americium is recovered by coprecipitation with radiopure cerium. The cerium fluoride is counted in a low-background proportional alpha counter. The method is effective for quantitative separation of americium from the lanthanides, other actinides, iron, and aluminum. Sensitivity is sufficient to detect activities as low as 0.50 disintegration per minute.