METHOD FOR PREVENTING RELEASE OF IMPURITIES FROM STRONG ACIDIC CATION EXCHANGE RESIN

摘要

PURPOSE:To attain to perfectly remove residual impurities, by mixing a strong acidic cation exchange resin, which has been regenerated after impurities were removed by repeating swelling and shrinkage in a predetermined solution, with an anion exchange resin and subsequently immersing the resulting mixture in pure water. CONSTITUTION:A process for successively contacting a strong acidic cation exchange resin with a mineral acid solution and an alkali solution in this order or a process for performing the same contact treatment in the reverse order is at least once performed or repeated performed two or more times. The resin repeats swelling and shrinkage by this operation and the greater part of impurities present in fine pores are discharged and removed to the outside of resin particles. Next, the strong acidic cation exchange resin is regenerated to an H-form according to a usual method and an anion exchange resin is added to the regenerated resin to obtain a state mixed as uniform as possible while the resulting mixture is immersed in pure water. By this method, because impurities present in the deep parts of fine pores are almost perfectly discharged into pure water, each of resins is sufficiently washed with water to be subjected to each use.