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High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes
SJR: 0.137 SNIP: 0.341 CiteScore™: 0.43

ISSN Imprimir: 1093-3611
ISSN On-line: 1940-4360

High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes

DOI: 10.1615/HighTempMatProc.v10.i1.90
pages 117-139

Simulation of Heavy Metals Volatility during the Vitrification of Fly Ashes by Thermal Plasma

Imed Ghiloufi
Imam University
Jean Marie Baronnet
Laboratory of Plasma Chemistry, University of Limoges,123 av. Albert Thomas, 87060 Limoges, France

RESUMO

This is a study of the heavy metals volatility during the vitrification of fly ashes by arc plasma. The vaporization model applied is based on the method of the free enthalpy minimization of the system coupled with the mass transfer equations at the reactional interface. This model enables us to determine the influence of the various parameters -like temperature, nature of the atmosphere of the furnace and matrix composition- on the volatility of lead, cadmium, zinc and arsenic. The results obtained indicate that an increase of the bath temperature produces an increase of the metals volatility. The oxygen content in the carrier gas permits a better metal's containments in the matrix, except in the case of the chromium which is more volatile in an oxidizing atmosphere. However the chlorine species trapped in the containment matrix accelerates considerably the evaporation of zinc, lead and cadmium, but don't affect the arsenic volatility. It has been noticed that it is possible to trap arsenic species in a solid state by the production of calcium arsenate if the lime content is increased. The results of the model are compared with those obtained from the experimental studies.