The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 31, 1994
Filed:
Apr. 20, 1992
Edward J Lahoda, Edgewood Borough, PA (US);
David C Grant, Gibsonia, PA (US);
Edward F Sverdrup, North Huntingdon, PA (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
Particulate material such as for example soil contaminated with heavy metals, radioactive species and organics, singly or in combination, is treated by first washing the contaminated material with a contaminant mobilizing solution comprising a leaching agent, a surfactant or a mixture thereof. Large particles, typically greater than 5 mm are mechanically separated, washed with water and returned to the site as recovered soil. Fines, along with contaminants dissolved or dispersed in the contaminant mobilizing solution are separated from intermediate sized particles by a countercurrent flow of the contaminant mobilizing solution, preferably in a mineral jig. The intermediate sized particles are then abraded in an attrition scrubber to dislodge attached mineral slimes or fines. These additional fines are separated from the intermediate sized particles with a countercurrent flow of wash water in a second mineral jig. For some applications, the intermediate sized particles can also be abraded in an attrition scrubber prior to size separation in the first mineral jig. The slurry of intermediate sized particles and wash water discharged from the second mineral jig is dewatered to produce additional recovered soil. If the contamination includes insoluble heavy metal particles, they are separated from the effluent discharged from the second mineral jig by density separation preferably in a cross-current flow jig, prior to dewatering. Various techniques can be used to separate the fines and the contaminants dissolved and dispersed in the waste slurries discharged by the two mineral jigs used for countercurrent flow size separation from the contaminant mobilizing solution which is recycled.