Phosphorus: In situ treatment for ZnCl{sub 2} formed by incineration of organic waste
- Commissariat a l`Energie Atomique, Bagnols-sur-Ceze (France). Rhone Valley Research Center
An incineration process has been developed in France for alpha-bearing radioactive organic waste. Such wastes contain polyvinyl chlorides and are rich in chlorine. They also contain zinc from neoprene and latex. Zinc chloride forms during incineration. At the combustion temperature, this gaseous compound is entrained with the smoke and recondenses during off-gas cooling. Depending on the incinerated waste composition, it may account for up to quasi totality of the particle matter recovered on the filters. Zinc chloride is hygroscopic at room temperature and is highly corrosive in contact with metals when hydrated. This implies that the facility must be maintained at a temperature of 200 C at all times. As a secondary waste material, the ZnCl{sub 2} must be stored in dry conditions, and eventually requires a specific containment or decontamination treatment. It is advantageous to inhibit the production of zinc chloride by favoring the formation of a more stable compound: zinc phosphate. A thermodynamic study of the stability of zinc phosphate with respect to zinc chloride showed that any excess P{sub 2}O{sub 5} over the stoichiometric fraction was sufficient to shift the equilibrium completely toward the phosphate side. This suggests that lowering the temperature also favors zinc phosphatation. Incineration tests were carried out with phosphorus in the waste material, either by increasing the quantity of waste containing P, or by using a phosphorus additive. The tests conclusively validated the thermodynamic study and showed that the phosphatation reaction was not limited by the kinetics. Other applications of phosphorus treatment could be envisaged: phosphatation of radionuclides which have highly volatile chlorides such as cesium chloride and phosphatation of heavy elements whose formation of chloride during incineration of domestic waste raises disposal problems.
- OSTI ID:
- 347644
- Report Number(s):
- CONF-980513-; ISSN 0956-053X; TRN: IM9923%%181
- Journal Information:
- Waste Management, Vol. 18, Issue 6-8; Conference: International conference on incineration and thermal treatment technologies, Salt Lake City, UT (United States), 11-15 May 1998; Other Information: PBD: 1998
- Country of Publication:
- United States
- Language:
- English
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