Method for treating waste containing stainless steel
US5877394A · kind A · utility
Inventors
Key dates
| Filing date | Oct 7, 1997 |
| Grant date | Mar 2, 1999 |
| Priority date | — |
| Expiry date | Oct 7, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P40/50
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A centrifugal plasma arc furnace is used to vitrify contaminated soils and other waste materials. An assessment of the characteristics of the waste is performed prior to introducing the waste into the furnace. Based on the assessment, a predetermined amount of iron is added to each batch of waste. The waste is melted in an oxidizing atmosphere into a slag. The added iron is oxidized into Fe.sub.3 O.sub.4. Time of exposure to oxygen is controlled so that the iron does not oxidize into Fe.sub.2 O.sub.3. Slag in the furnace remains relatively non-viscous and consequently it pours out of the furnace readily. Cooled and solidified slag produced by the furnace is very resistant to groundwater leaching. The slag can be safely buried in the earth without fear of contaminating groundwater.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.