PROBLEM TO BE SOLVED: To provide a method and an apparatus for rendering the soil, which contaminated with chemicals containing arsenic, harmless. SOLUTION: Contaminated soil a1containing moisture is charged into an externally heated rotary kiln 2 via a double damper 24, is indirectly heated, only discharging exhaust gas by an exhausting fan 3 without supplying oxygen-containing gas. The treated soil a2after heating is taken out of the system via a double damper 27. Thus, formation of a solid phase or a liquid phase arsenic oxide due to oxidation of evaporated arsenic component can be prevented, and re-attachment of toxic arsenic oxide to the soil under treatment can be prevented. At the same time, the vapor of the chemicals can be efficiently discharged out of the kiln 2 by an air current formed by the moisture vaporized in the kiln 2, thereby rendering the treated soil a2harmless. COPYRIGHT: (C)2005,JPO&NCIPI
