| abstract |
(57) [Summary] [Objective] To provide a method capable of converting a poorly water-soluble metal salt that has been discarded up to now into a reusable metal hydroxide and acid. [Structure] (A) A solution in which a sparingly water-soluble metal salt is dissolved is prepared, and (B) this solution is contacted with an alkaline aqueous solution to precipitate a metal hydroxide of the metal salt, and (C) the precipitated metal. The solution mixture containing hydroxide is subjected to a solid-liquid separation operation, (D) the metal hydroxide separated by the separation operation is recovered, and (E) the mother liquor separated by the separation operation is passed through an ion exchange membrane. A method for treating a sparingly water-soluble metal salt, which comprises subjecting it to electrodialysis to produce an aqueous acid solution and an aqueous alkali solution, and (F) recovering these aqueous solutions. |