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High Temperature Material Processes (An International Quarterly of High-Technology Plasma Processes)

An International Journal

ISSN for PRINT: 1093-3611

Institutional price:	$604.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2001, Volume5

152 pages

Issue price - $144.00

EVAPORATION SYNERGIES BETWEEN LEAD AND ZINC CONTAINED IN A FLY ASH MODEL IN ITS TREATMENT BY PTA

S. Bernard
Science des Procedes Ceramiques et de Traitements de Surface (SPCTS), CNRS UMR 6638, Faculte des Sciences de Limoges, 123, av. A. Thomas - 87060 Limoges Cedex, France

Pierre Fauchais
Laboratoire Sciences des Precedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS-Universite de Limoges, faculte des Sciences et Technique, conventionne avec le CEA n° M08, France

J. Jarrige
Science des Procedes Ceramiques et de Traitements de Surface (SPCTS), CNRS UMR 6638, Faculte des Sciences de Limoges, 123, av. A. Thomas - 87060 Limoges Cedex, France

J. P. Lecompte
Science des Procedes Ceramiques et de Traitements de Surface (SPCTS), CNRS UMR 6638, Faculte des Sciences de Limoges, 123, av. A. Thomas - 87060 Limoges Cedex, France

ABSTRACT

This study is about the evaporation synergies in the treatment of a fly ash model by a plasma transferred arc (stabilized by an argon flow). The fly ash model, composed of a zeolite matrix impregnated with lead and zinc salts, was treated in batch at room pressure under an argon atmosphere in a laboratory size plasma reactor.
The evaporation rates of lead and zinc were measured on-line by an ICP analysis system, for a fly ash model prepared with a zeolite matrix impregnated with lead and zinc chlorides and sulfates. It allowed to determine the influence of the applied arc power, the model composition and CaO addition on the evaporation rates. The presence of calcium or sodium oxide in the system reduced the melting bath temperature by nearly 200°C and allowed to devote a larger part of the available energy to the evaporation.
A thermodynamic study was made in order to understand the decomposition phenomena of the studied salts. By coupling these results to the enthalpy calculations and the evaporation rate measurements it was possible to suggest evaporation mechanisms.