| 摘要 |
<p>PURPOSE:To selectively leach out and recover Tl from a substance contg. Tl and As while inhibiting the leaching of As by subjecting the substance to alkali leaching at a prescribed pH value or above. CONSTITUTION:A substance contg. Tl and As produced from a process of refining nonferrous metal as an intermediate or residue is pulped with water. To the pulped soln. is added alkali, and alkali leaching is carried out at >=9pH and room temp. - 80 deg.C, especially 50-60 deg.C with stirring. After the leaching a cake is separated from the soln. by filtration and subjected to leaching again. Wen mixed alkali of NaOH and Na2CO3 is used as the alkali, improved settleability and filterability are obtd. After the leaching solid-liq. separation is performed by settling alone. To manufacture metallic Tl from the separated soln., the soln. is adjusted to about 3pH with sulfuric acid, and a zinc plate is suspended in the soln. Thus, Tl can be recovered as spongy Tl.</p> |
