| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a treatment method by which calcium is recovered as hydroxide from a calcium and heavy metal-containing material, and also, copper, zinc and lead can fractionally be recovered. <P>SOLUTION: The method includes a stage (A) where calcium and heavy metal- containing material such as fly ash and sulfuric acid are mixed into slurry of pH≤4, and the slurry is thereafter filtered to obtain solid components containing calcium sulfate and lead sulfate and liquid components containing copper and zinc; a stage (B) where the solid components obtained in the stage (A) and an alkalizing agent are mixed to obtain slurry of pH≥13.5, and the slurry is filtered to obtain liquid components containing calcium hydroxide and lead; a stage (C) where the powder of zinc or iron is added to the liquid components obtained in the stage (A), and thereafter, filtering is performed to obtain liquid components containing copper and zinc; and a stage (D) where the liquid components obtained in the stage (B) and the liquid components obtained in the stage (C) are mixed, thereafter, the pH of the mixed solution is controlled to 9 to 12, and subsequently, the mixed solution is filtered, so that solid components containing lead sulfate and zinc hydroxide, and liquid components are obtained. <P>COPYRIGHT: (C)2004,JPO</p> |
