| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a separating method of indium capable of separating indium from a sintered body of indium oxide and tin oxide after used mainly for a transparent conductive film or the like almost without loss and highly important to resource protection in the consideration that indium is extremely small in potential quantity on the earth and is a precious resource. SOLUTION: A mixture of indium oxide and tin oxide, which contains heavy metals, is dissolved by nitric acid to separate tin oxide insoluble in nitric acid, 2 phases of the nitric acid solution containing indium and other heavy metals and an anion exchange type extraction solvent containing phosphoric group or a mixed solution prepared by adding a hydrophobic organic solvent thereto are brought into contact with each other to extract indium to organic phase by adding an alkali solution to the nitric acid solution phase. Further the extraction residual solution is re-extracted to almost completely recover indium. In such a case, the anion exchange type extraction solvent containing phosphoric group is preferably di-(2-ethylhexyl) phosphoric acid and the hydrophobic organic solvent is preferably a cyclo alkane or a petroleum base hydrocarbon mixed liquid consisting essentially of the cyclo alkane.</p> |
