| 摘要 |
PROBLEM TO BE SOLVED: To reduce the generation amount of secondary waste by decontaminating the surface of metal waste with a ceramic material which is hardly crushed. SOLUTION: In a decontamination process in which blast treatment is conducted by blasting a blast material to metal waste 2 from a blast nozzle 3 within a decontamination bath 2, globular ceramic particles prepared by adding 6wt.% or less yttrium oxide to zirconium oxide, having a particle size of 50μm or more are used as the blast material. By selecting the angle of the blast nozzle 3 to the surface of the metal waste 5 in 60-90 deg. and distance between the blast nozzle 3 and the surface of the metal waste 5 in 80-100mm, grinding speed of metal is hastened, and thereby, radioactivity of the metal waste 5 is removed in a short time. Since ceramic particles of zirconium oxide are hardly crushed, stable decontaminating ability can be obtained even if they are repeatedly used. By narrowing the distribution range of the particles, ceramic particles are easily separated from the ground powder.
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