| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce disposal cost by reducing the generation amount of concentrated contaminated soil when washing cyanide-contaminated soil. <P>SOLUTION: The contaminated soil is formed into slurry; a polymer coagulant is added to the slurry and mixed and agitated to form flock by selectively coagulating only the earth particles of the sizes of 5-10 μm or larger in the slurry, and fine particles of less than 5-10 μm are dispersed in the slurry without causing coagulation. The cyanide is extracted in a dissolved state from the precipitated and separated flock by the alkali extraction, then cleaned soil consisting of the earth particles of 5-10 μm or larger is obtained by neutralizing, stabilizing and dewatering. The extracted water containing the cyanide in the dissolved state and supernatant of the slurry containing the fine particles of less than 5-10 μm are further subjected to the chemical clarification and dewatering to obtain the concentrated contaminated earth containing cyanide. <P>COPYRIGHT: (C)2012,JPO&INPIT |
