| 摘要 |
<p>PURPOSE:To efficiently recover vanadic acid contained in water of below a specific pH value while preventing leakage of vanadic acid into the treated water by contacting a free base type weakly or moderately basic anion exchange resin to the water and contacting the canadic acid-adsorbed resin to an aq. soln. of an alkali. CONSTITUTION:By feeding vanadic acid-contg. water of pH<= 3 to a free base type weakly or moderately basic anion exchange resin, the resin is first turned into a salt type one, the vanadic acid is then adsorbed, and the acid used to turn the resin is liberated. Next the vanadic acid-adsorbed resin is contacted to a 2-10% aq. soln. of an alkali such as alkali metal hydroxide or ammonia to turn the resin into a free base type one as well as to elute the acid. A mineral acid such as sulfuric or nitric acid is suitably used to regulate the vanadic acid-contg. water to pH<=3, and by lowering the pH as the vanadic acid content is raised, leakage of vanadic acid into the treated water is prevented.</p> |
