Process for the recovery of heavy metals such as lead from metal contaminated soil
OwnerBruce Edward Holbeininventor
Life of this patent
Estimating the term…
Abstract
A process for decontaminating a metal contaminated soil aggregate wherein at least one water soluble dialkyldithiocarbamate is admixed with an initial soil slurry so as to obtain a product aqueous soil slurry comprising one or more water insoluble metal-dialkyldithiocarbamate complexes which insoluble complexes may then be physically separated from the soil slurry to leave behind a product having a metal contamination level lower than that of the initial contaminated soil.
Claims43
A process for decontaminating a metal contaminated soil aggregate so as to obtain a product comprising a treated soil component having a metal content lower than that of the metal contaminated soil aggregate, said metal contaminated soil aggregate comprising at least one metal selected from the group comprising Pb, Hg, Cu, Cd, Zn, Ag, Ni, Co, Ga and Cr, said contaminated soil aggregate comprising a classified soil fraction representing soil particles having a size of from 0.15 mm and smaller, said process comprising
- providing an initial aqueous soil slurry comprising said metal contaminated soil aggregate;
- admixing at least one water soluble dialkyldithiocarbamate with said initial aqueous soil slurry so as to obtain a product aqueous soil slurry comprising one or more water insoluble metal-dialkyldithiocarbamate complexes, each of said water insoluble metal-dialkyldithiocarbamate complexes comprising a metal moiety;
- and
- separating one or more of said insoluble metal-dialkyldithiocarbamate complexes from said product aqueous soil slurry so as to obtain a treated aqueous slurry comprising a treated soil component having a metal content lower than that of said metal contaminated soil aggregate, and
- wherein the metal moiety of each of said one or more water insoluble metal-dialkyldithiocarbamate complexes is a member of the group comprising Pb, Hg, Cu, Cd, Zn, Ag, Ni, Co, Ga and Cr.
A process for decontaminating a metal contaminated soil aggregate so as to obtain a product comprising a treated soil component having a metal content lower than that of the metal contaminated soil aggregate, said metal contaminated soil aggregate comprising Pb, said contaminated soil aggregate comprising a classified soil fraction representing soil particles having a size of from 0.15 mm and smaller, said process comprising
- providing an initial aqueous soil slurry comprising said metal contaminated soil aggregate;
- admixing a dialkyldithiocarbamate with said initial soil slurry so as to obtain a product aqueous soil slurry comprising an insoluble Pb-dialkyldithiocarbamate complex;
- and
- separating insoluble Pb-dialkyldithiocarbamate complex from said product aqueous soil slurry so as to obtain a treated aqueous slurry comprising a treated soil component having a Pb content lower than that of said metal contaminated soil aggregate,
- said dialkyldithiocarbamate being selected from the group comprising dialkyldithiocarbamates of formula ##STR3## wherein R.sub.1 and R.sub.2 are independently selected from the group comprising alkyl groups of 1 to 6 carbon atoms, and M is selected from the group comprising alkali metals, alkaline earth metals, and ammonium groups of formula R.sub.3 R.sub.4 NHR.sub.5, R.sub.3, R.sub.4, and R.sub.5 being independently selected from the group comprising an atom of hydrogen and alkyl groups of 1 to 6 carbon atoms.
Dependencies are inferred from the claim text.