title: Reactions Between Vapor Phase Lead Compounds and In Situ Generated Silica Particles at Various Lead-Silicon Feed Ratios: Applications to Toxic Metal Capture in Combustors.
abstract: A detailed characterization was performed of the particles produced under various Pb:Si molar feed ratios for a maximum flow reactor temperature of 1000 °C. The silica particles formed in the high temperature region coagulated and only partially coalesced to form large agglomerate structures of high specific surface area. For a lead-only feed, the resulting particles were hydrocerussite with small but detectable amounts of massicot. As the silica precursor was inlet in excess amounts (Pb:Si < 1:12, the crystalline lead compounds disappeared and amorphous lead-silica complexes dominated. The particle morphology also changed from cylindrical, polygonal, and spherical shapes to large agglomerate structures composed of several size modes of primary particles. At Pb:Si molar feed ratios of 1:12 and 1:29, the particles making up the chainlike agglomerate structure were primarily spherical, with larger lead silicate spherical particles (=0.5 |im) attached to the agglomerate. The lead was found to be distributed throughout the large agglomerate structures, implying easier capture of lead emissions in particulate control devices.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Owens
authors.affiliation: a Aerosol and Air Quality Research Laboratory , University of Cincinnati , Cincinnati , Ohio , USA.
authors.forename: Pratim
authors.initials: P
authors.lastname: Biswas