| 摘要 |
<p>PURPOSE:To provide a method for recovering cadmium which is simple, excel lent in stability, and at a low cost from a leaching soln. of fume and ash pro duced by zinc metallurgy. CONSTITUTION:The acid leaching soln. of non-iron dry metallurgy fume and ash containing Cd, Zn and As is repeatedly used for leaching, and the dissolved component is concentrated. To the supernatant concentrated liquid or the supernatant liquid not concentrated, an alkali neutralizer or/and an oxide is added to change the liquid into pH 3-4. Then the supernatant liquid is controlled to have pH 4-4.5 by addition of Ca(OH)2, while air, oxygen, or/and oxidizing agent is used to oxidize the trivalent As into pentavalent. Succeedingly, iron (III) ion is added to the prepared liquid while an alkali neutralizer or/and oxide such as CdO, ZnO, etc., is added to maintain pH of the liquid to 4-4.5. The produced precipitate is separated from the liquid and the filtered liquid is sent to a substituting process to recover cadmium.</p> |
