| 摘要 |
PURPOSE:To efficiently regenerate used iron liquid, by heating a strong acidic ferric chloride soln. contg. heavy metal, mixing metallic iron therewith and allowing this mixture to react with each other, thereafter performing the solid- liquid separating operation at two times and then introducing gaseous chlorine. CONSTITUTION:Waste liquid which contains iron and one or more kinds of heavy metals excepting iron and consists of strong acidic ferric chloride is heated at about 60-120 deg.C. After agitating and mixing this soln. together with massive metal iron and allowing this mixture to react with each other, heavy metals such as Ni are removed from waste liquid by performing solid-liquid separation. Then after performing a second heating, the waste liquid is agitated and mixed with massive metallic salt and this mixture is allowed to react with each other, thereafter heavy metals such as Ni are more decreased by performing solid-liquid separation. Chlorine is introduced into the obtained filtrate. By this method, the generation of precipitate such as Fe(OH)2 is controlled and the removal of heavy metals can be smoothly performed and the spend etching waste liquid or the like can be regenerated at low cost. |
