| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method to efficiently separate alkaline earth metals from a cobalt aqueous solution containing at least one kind of alkaline earth metal ion such as calcium, magnesium and strontium as impurities. SOLUTION: Aqueous solution of cobalt chloride or the lie containing alkaline earth metal ion as impurities is neutralized using a neutralizing agent such as sodium hydroxide and sodium carbonate in a first stage and the generated precipitate is filtered and separated. Then, in a second stage, an oxidizing agent such as gaseous chlorine is added to the filtrate, and again neutralized while oxidizing the cobalt ion left in the solution to the trivalent, and the obtained precipitate is filtered to separate the alkaline earth metals represented by calcium and magnesium from cobalt. In this method, the neutralization in the first stage and in the second stage is preferably achieved at pH 6.0-7.0 and at pH 2.5-4.0, respectively.</p> |
