Patent Number: 056132387
Section: claims

1. A method of decontaminating soil containing hazardous metals, which comprises the steps of: (a) mixing in a closed vessel an ammoniacal liquid with a soil contaminated with at least one ion of a hazardous metal or metalloid to form a dispersion or slurry;  (b) separating an ammoniacal liquid-containing product from the dispersion or slurry of step (a) to yield a soil residue sufficiently free of ions of said hazardous metal or metalloid to permit reclamation, and  (c) separating the ammoniacal liquid from the ammoniacal liquid-containing product of step (b) to yield a hazardous metal or metalloid-containing residue for disposal or further treatment.  (a) mixing in a closed vessel an ammoniacal liquid with a soil contaminated with at least one ion of a hazardous metal or metalloid to form a dispersion or slurry;  (b) allowing soil particles to selectively precipitate from the dispersion or slurry of step (a) to provide a lower phase comprising a precipitate of soil particulates while forming an upper liquid-solid phase comprising soil fines dispersed in said ammoniacal liquid;  (c) separating said upper liquid-solid phase from said lower phase, the precipitate of soil particulates of said lower phase being sufficiently free of ions of said hazardous metal or metalloid to permit reclamation of said soil particulates, and  (d) separating the ammoniacal liquid of said upper liquid-solid phase to yield a residue comprising the hazardous metal or metalloid for disposal or further treatment.  (a) mixing in a closed vessel an ammoniacal liquid with a soil contaminated with at least one ion of a hazardous metal or metalloid to form a dispersion or slurry;  (b) treating the dispersion or slurry of step (a) with solvated electrons by contacting with a reactive metal selected from the group consisting of an alkali metal, alkaline earth metal and aluminum;  (c) separating an ammoniacal liquid-containing product from said dispersion or slurry of step (b) to yield a soil residue sufficiently free of ions of the hazardous metal or metalloid to permit reclamation of the soil, and  (d) separating said ammoniacal liquid from said ammoniacal liquid-containing product of step (c) to yield a hazardous metal or metalloid-containing residue for disposal or further treatment. 2. The method of claim 1 wherein the ammoniacal liquid is anhydrous liquid ammonia or an ammonia-containing solution. 3. The method of claim 2 wherein the ion of said hazardous metal or metalloid is a member selected from the group consisting of radioactive metals, nonradioactive metals and mixtures thereof. 4. The method of claim 2 wherein the ion of said hazardous metal or metalloid is nonradioactive and is a member selected from the group consisting of arsenic, antimony, selenium, cadmium, cobalt, mercury, chromium, lead and mixtures thereof. 5. The method of claim 2 wherein said ammoniacal liquid-containing product of step (b) comprises a coordination compound formed from the ion of a hazardous non-radioactive metal or metalloid and ammonia. 6. The method of claim 5 wherein the coordination compound is a metal-ammonia ligand complex. 7. The method of claim 2 wherein said ammoniacal liquid-containing product of Step (b) comprises a co-ordination compound formed from the ion of a hazardous metal or metalloid and cyanide ion. 8. The method of claim 1 including the step of recycling the ammoniacal liquid of step (c). 9. The method of claim 1 including the addition of a chelating agent to said closed vessel. 10. The method of claim 1 wherein the contaminated soil comprises mainly sand and includes the step of adding a clay to said vessel. 11. A method of decontaminating soil containing hazardous metals, which comprises the steps of: 12. The method of claim 11 including the step of recovering and recycling the ammoniacal liquid from step (d). 13. The method of claim 11 wherein the ammoniacal liquid of step (a) is anhydrous liquid ammonia or an ammonia-containing solution. 14. The method of claim 11 wherein the ion of said hazardous metal or metalloid is a member selected from the group consisting of radioactive metals, nonradioactive metals and mixtures thereof. 15. The method of claim 11 wherein the ion of said hazardous metal or metalloid is nonradioactive and is a member selected from the group consisting of arsenic, antimony, selenium, cadmium, cobalt, mercury, chromium, lead and mixtures thereof. 16. The method of claim 14 wherein the soil comprises a member selected from the group consisting of clay, disintegrated rock, sand, organic matter and mixtures thereof. 17. The method of claim 11 including the addition of a chelating agent to said closed vessel. 18. The method of claim 11 including the addition of a ligand complexing agent to said closed vessel. 19. The method of claim 18 wherein the ligand complexing agent is a cyanide ion yielding salt or compound. 20. The method of claim 11 wherein the soil is mainly sand and step (a) includes the addition of a clay to said closed vessel. 21. The method of claim 11 wherein the soil of step (a) comprises a mixed waste. 22. The method of claim 21 wherein said mixed waste comprises an ion of a hazardous nonradioactive metal or metalloid and a nuclear waste. 23. The method of claim 21 wherein said mixed waste comprises an ion of a hazardous nonradioactive metal or metalloid and an ion of a radioactive isotopic metal. 24. The method of claim 22 wherein the nuclear waste comprises at least one radionuclide. 25. The method of claim 24 wherein the radionuclide is a member of the actinide series. 26. The method of claim 23 wherein the radioactive isotopic metal is a member selected from the group consisting of uranium, plutonium, thorium and mixtures thereof. 27. A method of decontaminating soil, which comprises the steps of: 28. The method of claim 27 wherein step (b) is performed by circulating at least a portion of the ammoniacal liquid through a by-pass containing the reactive metal to form solvated electrons, which are recirculated to the closed vessel for treating the contaminated soil. 29. The method of claim 27 wherein the ion of the hazardous metal or metalloid is a member selected from the group consisting of radioactive metals, nonradioactive metals and mixtures thereof. 30. The method of claim 29 wherein the ammoniacal liquid of step (a) is anhydrous liquid ammonia or an ammonia-containing solution. 31. The method of claim 29 wherein the ion of said hazardous metal or metalloid is nonradioactive and is a member selected from the group consisting of arsenic, antimony, selenium, cadmium, cobalt, mercury, chromium, lead and mixtures thereof. 32. The method of claim 30 wherein the soil is contaminated with chromium VI, and is reduced by the solvated electrons. 33. The method of claim 29 wherein the soil comprises a member selected from the group consisting of clay, disintegrated rock, sand, organic matter and mixtures thereof. 34. The method of claim 29 wherein the soil is mainly sand and step (a) includes the addition of a clay to the vessel. 35. The method of claim 27 wherein the soil of step (a) comprises a mixed waste. 36. The method of claim 35 wherein the mixed waste comprises an ion of a hazardous nonradioactive metal or metalloid and a nuclear waste. 37. The method of claim 35 wherein the mixed waste comprises an ion of a hazardous nonradioactive metal or metalloid and an ion of a radioactive isotopic metal. 38. The method of claim 36 wherein the nuclear waste comprises at least one radionuclide. 39. The method of claim 38 wherein the radionuclide is a member of the actinide series. 40. The method of claim 39 wherein the radioactive isotopic metal is a member selected from the group consisting of uranium, plutonium, thorium and mixtures thereof. 41. The method of claim 35 wherein the mixed waste comprises an ion of a hazardous metal or metalloid and an organic compound. 42. The method of claim 41 wherein the organic compound is a halogenated organic compound. 43. The method of claim 42 wherein the halogenated organic compound is a member selected from the group consisting of PCBs, dioxin and pesticides.