Volatilization behavior of lead from molten slag under conditions simulating municipal solid waste melting

To reutilize molten slag derived from an ash melting process, the lead volatilization mechanism under reducing conditions was investigated. Reducing conditions were established by introducing a CO-CO 2 -N 2 gas mixture to the reactor or by adding graphite to the molten slag prior to the experiments....

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Bibliographic Details
Published in:Journal of material cycles and waste management 2008-03, Vol.10 (1), p.19-23
Main Authors: Nakada, Hiroyuki, Mihara, Naoto, Kawaguchi, Yuuki, Osada, Shohichi, Kuchar, Dalibor, Matsuda, Hitoki
Format: Article
Language:English
Subjects:
Ash
Behavior
Carbon dioxide
Civil Engineering
Cooling
Engineering
Environmental Management
Experiments
Furnaces
Graphite
Heavy metals
Lead
Lead content
Melting
Metals
Municipal solid waste
Municipal solid wastes
Q1
Slag
Special Feature: Original Article
Studies
Viscosity
Waste Management/Waste Technology
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Summary:To reutilize molten slag derived from an ash melting process, the lead volatilization mechanism under reducing conditions was investigated. Reducing conditions were established by introducing a CO-CO 2 -N 2 gas mixture to the reactor or by adding graphite to the molten slag prior to the experiments. As samples, two types of simulated molten slag composed of CaO-SiO 2 -Al 2 O 3 mixed with PbO were used and the lead volatilization behavior was studied at 1773 K. It was found that the lead volatilization rate increased on increasing the amount of reducing agent for both graphite and the CO-CO 2 gas mixture. For the CO-CO 2 reducing gas mixture, this increase was mainly attributed to PbO conversion to Pb. For the addition of graphite, the increase in lead volatilization ratio was considered to partially result from PbO conversion to Pb and partially from a reaction of graphite with SiO 2 yielding volatile SiO. The volatile SiO gas was then emitted from the furnace, which brought about a reduction in the SiO 2 content of the slag. As a result, the slag viscosity decreased, which led to an enhancement of the lead volatilization ratio.
ISSN:1438-4957
1611-8227
DOI:10.1007/s10163-007-0193-x