| 摘要 |
<p>PURPOSE:To recover zinc sulfate having high purity efficiently by adding ferric polysulfate to the precipitate formed by subjecting zinc-contg. dust to a water treatment and separating the same then washing away the solutionized alkaline (earth) metal from the precipitate and adding a sulfuric acid acid thereto. CONSTITUTION:The zinc dust is subjected to aeration washing with the water flowing a 7-10m<3>/dust (t) and is rested. The supernatant liq. contg. Cl, Na, K, etc., which are water soluble impurities is neutralized and discarded. On the other hand, the sulfuric acid and water is added to the precipitate to adjust the hold the pH to and at 6.5-5.9 and further the ferric polyphosphate is added thereto and the soln. is air-stirred to elute and remove the solutionized alkaline (earth) metal. The precipitate is further repeatedly washed with the warm water or water to prevent the formation of double salts. The anions such as F<-> and Cl<-> except the sulfate ions and suspended fine particles are neutralized and adsorbed by the basic ion having high positive electric charge of the polyoxy salt such as [Fe2(OH)2]<4+> or [Fe2(OH)]<5+>. As a result, the elution of the above- mentioned suspended fine particles in the subsequent stage for extracting zinc by sulfuric acid and zinc sulfate having high purity is recovered.</p> |
