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US 2013/0074733 A1Published application
Method of cleaning a material
OwnerLalit Chordia, Jose L. Martinez +1inventors
InventorsLalit Chordia, Jose L. Martinez, Bhishmakumar Desai
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Abstract
Solid waste of metallic or plastic composition is cleansed of contaminants by solvent extraction using a combination of primary solvent and co-solvents that may be pressurized and heated to above the critical state. The process is particularly applicable to the remediation of solids contaminated with polychlorinated biphenyls. Contamination can be reduced to less than two parts per million (by weight).
Claims28
A method for removing polychlorinated biphenyl contaminants from contaminated plastics or metals, comprising the steps of:
- placing the plastics or metals in an extraction vessel;
- heating a solvent to above its critical temperature;
- pressurizing the vessel with the heated solvent to a predetermined pressure;
- pumping a stream of fresh solvent into the extraction vessel while an extract stream of solvent with dissolved contaminants therein flows out of the extraction vessel;
- separating the dissolved contaminants in the solvent and collecting the separated contaminants;
- pumping the separated solvent back to the extraction vessel;
- depressurizing the extraction vessel;
- unloading solid raffinate from the extraction vessel;
- and
- wherein the solid raffinate contains less than 2 parts per million of polychlorinated biphenyl.
7 more elements
Dependencies are inferred from the claim text.