In situ vitrification: Test results for a contaminated soil melting process
Pacific Northwest Laboratory (PNL) is developing in situ vitrification (ISV), a remedial action process for treating contaminated soils. In situ vitrification is a thermal treatment process that converts contaminated soil into a chemically inert and stable glass and crystalline product. Figure 1 depicts the process. A square array of four molybdenum/graphite electrodes is inserted into the ground to the desired treatment depth. Because soil is not electrically conductive when the moisture has been driven off, a conductive mixture of flaked graphite and glass frit is placed between the pairs of electrodes as a starter path. An electrical potential is applied to the electrodes to establish an electric current in the starter path. The resultant power heats the starter path and surrounding soil to 2000/degree/C, well above the initial soil-melting temperature of 1100 to 1400/degree/C. The graphite starter path is eventually consumed by oxidation, and the current is transferred to the molten soil, which is electrically conductive. As the molten or vitrified zone grows, it incorporates radionuclides and nonvolatile hazardous elements, such as heavy metals, and destroys organic components by pyrolysis. The pyrolyzed byproducts migrate to the surface of the vitrified zone, where they burn in the presence of oxygen. A hood placed over the area being vitrified directs the gaseous effluents to an off-gas treatment system. 5 refs., 1 fig., 1 tab.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 5965319
- Report Number(s):
- PNL-SA-16584; CONF-890521-11; ON: DE89014459
- Resource Relation:
- Conference: 8. international conference on thermal destruction of hazardous, radioactive, infectious and mixed wastes, Knoxville, TN, USA, 1-5 May 1989; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
Similar Records
The In Situ Vitrification Project
In situ vitrification: An innovative thermal treatment technology
Related Subjects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
ALPHA-BEARING WASTES
WASTE PROCESSING
CHEMICAL WASTES
COMBUSTION
IN-SITU PROCESSING
OFF-GAS SYSTEMS
ORGANIC COMPOUNDS
PERFORMANCE TESTING
RADIOISOTOPES
VITRIFICATION
CHEMICAL REACTIONS
ISOTOPES
MANAGEMENT
MATERIALS
OXIDATION
PROCESSING
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
TESTING
THERMOCHEMICAL PROCESSES
WASTE MANAGEMENT
WASTES
052001* - Nuclear Fuels- Waste Processing
053000 - Nuclear Fuels- Environmental Aspects