| 摘要 |
PROBLEM TO BE SOLVED: To coprecipitate and separate transition metals, for example, not only transuranic elements but also, ruthenium and technetium, each of which is hardly coprecipitated with a precipitate by a conventional method, in a radioactive waste liquid. SOLUTION: This method for coprecipitating transition metals in a solution with a precipitate and separating the transition metals from the solution, comprises allowing a multivalent metal ion capable of forming a hydroxide precipitate in an alkaline pH region and a zorovalent metal (a simple elemental metal substance itself which is not an ion or compound and preferably a powdery metal) capable of reducing the transition metals to coexist in the solution, alkalinizing the resulting solution, if not alkaline, to form a hydroxide precipitate of the multivalent metal and concurrently to coprecipitate the transition metals with the multivalent metal precipitate, and separating the resulting precipitate from the solution; wherein more specifically, for example, an iron (II) or iron (III) compound, each being soluble in the solution, and powdery iron are added to the solution and the resulting solution is alkalinized.
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