WASHING METHOD WITH SUPERCRITICAL FLUID

摘要

PROBLEM TO BE SOLVED: To safely wash and remove hazardous materials without polluting the work environment and without allowing an operator to directly hold these materials on to contact with these materials. SOLUTION: Articles 11 are housed in a vessel and are installed in a washing tank 2. Supercritical carbon dioxide 12 and an auxiliary solvent 13 are supplied into the washing tank 2 and are brought into contact with the articles 11, by which the articles 11 are washed. As a result, the PCB contained in the articles 11 is removed. As to the articles 11 having a high degree of hermeticity, the articles are pulverized and destroyed by a device 14 to allow the easier infiltration of the supercritical carbon dioxide 12 therein. The concn. of the PCB included in the supercritical carbon dioxide 12 discharged from the washing tank 2 is detected in a detecting section 6 after washing and the washing state is monitored. The supercritical carbon dioxide 12 is introduced to a separator 4 and is cooled and decompressed down to the critical point or below, by which the supercritical carbon dioxide is returned to ordinary carbon dioxide and is separated from the PCB. The PCB is transported through piping 5d to a hazardous material treatment facility.