Abstract: A method and apparatus for decontaminating a substance contaminated with radioactivity, in particular, shot blasting grit contaminating with radioactivity. The method comprises: contaminated substance washing the substance to be decontaminated with chelate liquid; draining the chelate liquid; raising the temperature of the substance to a level not lower than the boiling point of a solvent by means of hot air; supplying the solvent to the substance and rapid by vaporizing the solvent; removing the remaining chelate fluid liquid by the force of the vaporization and draining and drying the substance.

Abstract: A solution composed of a chelating solution and/or an organic acid is applied to radioactive metals to form a radioactive metal solution. The metal solution is increased in its electrical conductivity by addition of an alkaline agent, followed by electrolysis by an electrolyzer to thereby convert metal ions in the metal solution to hydroxides of low solubility and to separate the hydroxides as a filter cake by subsequent filtration. The filtrate is irradiated with ultraviolet rays for further decomposition of remaining organic matter and then filtered by a device using reverse osmosis. The resultant filtrate is recycled as clean water for use for a chelating solution and electrolytic solution, or is discharged. The metal ions precipitated by treatment with the alkaline agent prior to electrolysis as matter of low solubility is separated from the filtrate which is thereafter electrolyzed.

Abstract: A method of effectively decontaminating a substance contaminated with radioactivity, in particular, shot blasting grit contaminated with radioactivity, and a decontaminating apparatus which makes it possible for a single apparatus to perform all of the decontamination processes without moving the contaminated substance from one apparatus to another for each process, thereby realizing reduction in the installation space and achieving an improvement in operational efficiency. The method comprises: decontaminating a contaminated substance by washing it with achelate liquid; draining the chelate liquid; raising the temperature of the substance to a level not lower than the boiling point of a solvent by means of hot air; supplying the solvent to the substance to result in rapid vaporization thereof; removing the remaining chelate fluid liquid by the force of this vaporization and draining the same;and drying the substance.

Abstract: A method for recovering solvent vapor in a manner which requires less power using an apparatus which is smaller in size, has a longer life, and is capable of being operated without reducing recovering efficiency, including locating an inlet of a suction pipe at a position within the container between the liquid surface of the solvent and an upper edge of the container, wherein the opening of the suction pipe is open downward, and drawing the vapor from the upper surface of the solvent in the container.