| 摘要 |
PURPOSE:To remove the clads deposited on an ion exchange resin by treating the resin with a mixed soln. of oxalic acid or its salt and a reducing agent or a mixed soln. of oxalic acid or its salt and a reducing agent and an inorg. acid then passing the inorg. acid therethrough. CONSTITUTION:The ion exchange resin deposited thereon with clad, that is, a product resulted by corrosion consisting essentially of iron compds. such as iron oxide is treated with a mixed soln. of oxalic acid or its salt and a reducing agent (e.g.; Na2SO3) or a mixed soln. of the same and an inorg. acid (e.g.; sulfuric acid). If the inorg. acid is passed therethrough after the treatment, the rate of removal of iron from the anion exchange resin is >=90%, and the rate of removal of iron from the cation exchange resin is 80-90%. If the ion exchange resin deposited with the clad is a cation exchange resin, the kind of the reducing agent to be used is preferred to contain no cations (e.g.; L-ascorbic acid). If the ion exchange resin having no deposition of the clad is a resin mixture, the resin mixture is separated in individual columns, whereafter the resins are subjected separately to the regeneration by removing iron. |
