| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for recovering phosphorus by which phosphorus is efficiently eluted from a sewage-sludge incineration ash, and the deposition of calcium sulfate is reduced. SOLUTION: The sewage-sludge incineration ash is added to sulfuric acid to elute the phosphorus component in the ash, and phosphorus is recovered. In this method, the phosphorus component is eluted in an ordinary-temp. range, the ratio of the solid ash to liq. sulfuric acid (pulp density) is controlled to elute the phosphorus component while preventing the elution of calcium. The solid-liq. ratio (pulp density) is preferably controlled to <=0.04 g/ml to elute the phosphorus component.</p> |
