Mechanism and kinetics of lead capture by kaolinite in a downflow combustor

Davis, Sheldon B.; Wendt, Jost O.L.

doi:10.1016/s0082-0784(00)80695-5

Cited by 26 publications

(33 citation statements)

References 16 publications

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“…Evidence of previously molten lead/kaolinite product particles was observed at all temperatures investigated (Davis and Wendt 2000a). Indeed, melting had been shown by others (Mwabe and Wendt 1996;Scotto et al 1992;Linak et al 1995) to 866 T. K. GALE AND J. O. L. WENDT enhance capture by kaolinite.…”

Section: Introductionsupporting

confidence: 61%

Mechanisms and Models Describing Sodium and Lead Scavenging by a Kaolinite Aerosol at High Temperatures

Gale

Wendt

2003

Aerosol Science and Technology

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High temperature mechanisms of interaction between a dispersed kaolinite aerosol and vaporized sodium and lead were investigated using experimental data obtained from an 18 kW downflow furnace. The validity of using aerosol size fractionation to determine the extent of reaction between metal and substrate was confirmed through a series of specialized tests. The reaction stoichiometries for the Na/kaolinite and Pb/kaolinite systems were found to differ from literature values but were similar to each other. New light was shed on the nature of the reaction products for the Na/kaolinite and Pb/kaolinite systems, and for semivolatile metal/kaolinite sorbent systems in general. Modified reaction mechanisms were developed that accommodate key-observed processes (i.e., both enhancing and inhibitory substrate-melting processes). Rate coefficients for each system were quantitatively determined. Mechanisms are interpreted in the light of known information on the structure and nature of kaolin clay and based on observed phase transformations of the Na/kaolinite and Pb/kaolinite systems. The new models for high temperature Na/kaolinite and Pb/kaolinite interactions compared well to both new and literature data. These models can be used to predict and optimize the scavenging of vaporized sodium and lead by kaolinite mineral particles in fossil fuel-fired systems and waste incinerators.

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Section: Introductionsupporting

confidence: 61%

Mechanisms and Models Describing Sodium and Lead Scavenging by a Kaolinite Aerosol at High Temperatures

Gale

Wendt

2003

Aerosol Science and Technology

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“…This is in contrast to previous results for lead and sodium (37,45,46). Figure 4 indicates a maximum sorption of 80% was achieved for the test series examined…”

Section: Measured Effects Of Sorbent Injection Temperature and Sorbencontrasting

confidence: 92%

“…This may suggest a sorption reaction with low activation energy and a deactivation reaction with higher activation energy (37). SEM micrographs showing melting at T inj =1700 K also support this hypothesis.…”

Section: Measured Effect Of Sorbent Injection Temperaturementioning

confidence: 63%

“…Results are shown on Table 2 and are compared to literature results for the lead-kaolinite system (37). With sorbent deactivation parameters equivalent to those used by Davis and Wendt (37) and Gale and Wendt (46), best fit cesium sorption parameters [k 1 =5.2e+2 m 3 /(mol·s), and E 1 =8.7e+1 J/mol] produce the response curve presented in Figure 4 with an r 2 =0.95.…”

Section: Kinetic Model For Cesium Sorption On Dispersed Kaolinitementioning

confidence: 93%

“…Kaolinite, a natural mineral composed of silica and alumina (Al 2 O 3 ·2SiO 2 ·2H 2 O), has been shown to be an effective sorbent for the high temperature capture of vapor-phase lead, cadmium, and sodium (32,33,34,35,36,37,38,39). Kaolinite also has the advantages that it is compatible with subsequent vitrification and cement processes.…”

Section: Sorbent Technologymentioning

confidence: 99%

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