Contaminated soil restoration method

  • US 5,045,240 A
  • Filed: 05/01/1989
  • Issued: 09/03/1991
  • Est. Priority Date: 05/01/1989
  • Status: Expired due to Term
First Claim
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1. A method of treating waste material contaminated with soluble radioactive species comprising the steps:

  • (1) providing waste material containing soluble radioactive species and separating that portion of the waste material found to be contaminated, to provide contaminated waste material;

    (2) crushing the contaminated waste material so that it has a particle size below 420 micrometers, determining the contaminant, the contaminated waste material density, and identifying the particle size range of the most severely contaminated fraction of the contaminated waste material by separation into a plurality of particle size fractions and scanning each fraction for radioactivity or chemically analyzing each fraction;

    (3) passing the contaminated waste material, having a known density, into a fluidized bed apparatus where an aqueous leach solution, having a chemical composition effective to leach soluble contaminants present in the contaminated waste material, contacts the contaminated waste material at an upward velocity effective to entrain and remove, at the top of the apparatus, particles including the particle size range that is determined to contain the most severely contaminated fraction of the contaminated waste material, to provide a severely contaminated, top effluent slurry containing solubilized, severely contaminated species, and a bottom effluent slurry containing disposable, cleaned waste where each slurry contains the aqueous leach solution;

    (4) removing the leach solution from the severely contaminated effluent slurry, to provide aqueous leach solution containing solubilized, severely contaminated species, and cleaned solids waste; and

    (5) passing the aqueous leach solution from step (4) through an ion removal apparatus effective to remove the solubilized, severely contaminated species from the aqueous leach solution, to provide cleaned, aqueous leach solution.

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