Situ formation of apatite for sequestering radionuclides and heavy metals
US6592294B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 25, 2001 |
| Grant date | Jul 15, 2003 |
| Priority date | — |
| Expiry date | Jan 17, 2022 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB09C1/08
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
Methods for in situ formation in soil of a permeable reactive barrier or zone comprising a phosphate precipitate, such as apatite or hydroxyapatite, which is capable of selectively trapping and removing radionuclides and heavy metal contaminants from the soil, while allowing water or other compounds to pass through. A preparation of a phosphate reagent and a chelated calcium reagent is mixed aboveground and injected into the soil. Subsequently, the chelated calcium reagent biodegrades and slowly releases free calcium. The free calcium reacts with the phosphate reagent to form a phosphate precipitate. Under the proper chemical conditions, apatite or hydroxyapatite can form. Radionuclide and heavy metal contaminants, including lead, strontium, lanthanides, and uranium are then selectively sequestered by sorbing them onto the phosphate precipitate. A reducing agent can be added for reduction and selective sequestration of technetium or selenium contaminants.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.