Process for total environmental remediation of a phosphorus contaminated site
US6955796B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 2003 |
| Grant date | Oct 18, 2005 |
| Priority date | — |
| Expiry date | Apr 16, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/908
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A process is disclosed for recovering elemental phosphorus from an aqueous sludge and converting the residue into non-hazardous waste. The sludge is separated into (1) a slurry of water containing suspended phosphorus and dirt particles and (2) coarse solids. A flocculating agent is added to the slurry to agglomerate the suspended phosphorus and dirt particles, which are recovered from the water and are heated to melt elemental phosphorus particles. A coalescing agent is added to coalesce the melted elemental phosphorus, which is separated from the dirt particles. The coarse solids are mixed with hot water to melt the phosphorus sludge, which is separated from inert solids. The solids are heated to burn any residual elemental phosphorus. The separated molten phosphorus sludge is stirred with a solution of chromic acid to recover the phosphorus as a separate phase. A reducing agent is added to the remaining water and solids to reduce the Cr+6 to Cr+3. Finally, an alkali is added to the water and solids to react the residual phosphorus and form phosphorous compounds. The reaction mass is filtered and the filter cake can be placed in a landfill as a non-hazardous waste.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.