Extraction method and apparatus for cleaning contaminated soil

US5507953A · kind A · utility

Assignees

• Peter Flakus · DE
• Horst Muehr · DE
• Erwin Wessling · DE

Inventors

• Rainer Machlitt · Wuppertal, DE
• Frank Meyer · Essen, DE

Key dates

• Filing date: Nov 5, 1993
• Grant date: Apr 16, 1996
• Expiry date: Nov 5, 2013

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D2011/002
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The method of cleaning soil contaminated with contaminants includes comminuting contaminated soil to form a comminuted contaminated soil; filling the comminuted contaminated soil into a countercurrent extractor from above under an inert gas atmosphere so that the comminuted contaminated soil moves as a travelling bed downward through the countercurrent extractor; feeding a solvent, advantageously acetone, into a lower portion of the countercurrent extractor so that the solvent flows upward through the travelling bed to form a decontaminated soil at the bottom of the extractor and a contaminant-charged solvent portion taken from a middle portion; supplying a conveying liquid to the lower portion of the countercurrent extractor so as to transfer the decontaminated soil from the countercurrent extractor to a filter device having a belt filter; and separating the decontaminated soil in the filter device into a cleaned soil and a reusable conveying liquid. A feeder device is provided for the filter device which avoids clogging of the moving belt filter by the soil when the soil has a high proportion of silt.