METHOD FOR TREATING ION EXCHANGE RESIN

PROBLEM TO BE SOLVED: To recover metal ions without adding any causative agents of secondary wastes by removing ion exchange groups from used ion exchange resin, separating the water containing removed metal ions and the residue of the ion exchange resin, keeping the water containing the metal ions and the ion exchange groups at high temperature and pressure to react it and recovering the metal ions in the form of hydroxides or oxides. SOLUTION: In a process 1 for removing ion exchange groups, the water is kept at a temperature of 20 deg.C or lower and under the pressure equal to or higher than the saturated vapor pressure of water to desorb and remove ion exchange groups from an ion exchange resin. In the first solid-liquid separation process 2, a solid phase containing the residue of the resin is separated from a liquid phase. In a process 3 for recovering metal ions, the liquid phase containing sulfuric acid and metal ions is kept at supercritical temperature and pressure for a certain time to cause a reaction. After precipitating the metal ions in a solution in the form of hydroxides or oxides, a solid phase is separated from a liquid phase in the second solid liquid separation process 4. Metal oxides and sulfuric acid are recovered in the solid phase and in the liquid phase respectively. The residue is incinerated in an incineration process 5.