Precipitating separation method for radioactive iodine compound

Liquid wastes containing radioactive iodine compounds are kept at higher than 20degC and lower than 80degC, and 0.1 to 3 parts by weight of a reducing agent and an appropriate amount of silver nitrate are added to 100 parts by weight of the liquefied wastes and stirred for 0.5 to 72 hours to form precipitates. IO3 which is hardly precipitated by an existent coagulation/precipitation method is reduced to I- by the addition of the reducing agent and reacted with the silver nitrate, to form precipitates (AgI). Then, radioactive iodine compounds contained in the radioactive liquid wastes are almost separated from the liquid wastes, and iodic acids can be precipitated, thereby enabling to remarkably reduce the amount of radioactive iodine released to the circumstances. (N.H.)