Decontamination of polluted soils

  • US 5,405,579 A
  • Filed: 07/22/1992
  • Issued: 04/11/1995
  • Est. Priority Date: 07/22/1991
  • Status: Expired due to Fees
First Claim
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1. A process for the decontamination of an excavated soil containing soil pollutants and water moisture, comprising the steps of:

  • passing the excavated soil to a thermal treatment zone, heating the soil in the absence of oxygen and under superatmospheric pressure by indirect heat exchange to a temperature not higher than 650°

    C. under sufficient time-temperature conditions, such that the water moisture in the soil is vaporized to form steam, contacting a desorption medium comprising said steam with said soil in the absence of oxygen, and under sufficient time-temperature conditions to desorb the soil pollutants from the soil, cooling the desorption medium containing the soil pollutants in a scrubbing step, separating the cooled and scrubbed desorption medium into individual phases at least one phase being a gaseous phase, dissolving any precipitating solids in the gaseous phase in a solvent and cooling the gaseous phase.

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