| 摘要 |
<p>The noxious element arsenic may be removed with high efficiency from iron hydroxide sludge by first subjecting that sludge first to a thermal treatment in the presence of air or oxygen and of an alkaline reagent and next extracting the treated material with water. The arsenic present in the extract is thereupon adsorbed to an anion exchanger, eluted with an alkaline aqueous liquid and precipitated in salt form from it. The residual sludge is better suitable for re-use or for another useful application. The method may also be used for removing other amphoteric elements such as P, Cr, Al, Mn, Zn and the like and is not only applicable to iron hydroxide sludge but also to other sludge types and several types of solid waste materials.</p> |
