| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain cleaned soil having a drastically lowered oil content by removing impurities from soil the oil content of which cannot be lowered even if the soil is repeatedly subjected to washing treatment. <P>SOLUTION: In a soil washing unit 3, a surfactant and washing water are added to the soil contaminated with oil and stirred for a specified time, oil is removed from soil particles of the soil so that the oil adhering on the surface of the soil particles is removed, and water is added, in a stirring tank 24, to the soil particles from which the oil adhering on the surface is removed to produce a slurry. Magnetic substances and non-magnetic substances contained in the slurry are magnetically sorted and separated by a magnetic separator 25, and the magnetic substances such as iron debris adsorbing a large amount of oil are removed as the impurity. In a gravity separator, the non-magnetic substances separated as described above are classified into a low specific gravity substance and a high specific gravity substance by specific gravity, and burnt coal residues and the like adsorbing a large amount of oil is removed as the impurity. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
