It is quite important to know the reactivity and behavior of Pb contained in steelmaking dust, or bottom ash and fly ash generated from municipal solid waste incineration process with chlorine. In the present study, chlorination and evaporation kinetics of PbO-PbCl
2 melt have been investigated in Ar-Cl
2-O
2 atmosphere from 1023 to 1123 K. The weight of PbO specimen increased first and then decreased in Ar-Cl
2-O
2 stream during experiments, which phenomena mean that produced PbCl
2 by PbO chlorination formed liquid oxychloride phase of PbO-PbCl
2 system and then PbCl
2 evaporated. Increase of partial pressure of chlorine increased the initial chlorination rate, however no effect on the latter evaporation rate was observed. Decrease of maximal weight gain of specimen and the slight increase of evaporation rate were observed with increasing partial pressure of oxygen. Activation energies of chlorination and evaporation of PbO-PbCl
2 melt in the steady state were 35 kJ/mol and 156 kJ/mol, respectively. Evaporation rate of PbO-PbCl
2 was also investigated at 1073 K in Ar-O
2 atmosphere, however the change of evaporation rate with changing partial pressure of oxygen was within experimental error. Measured evaporation rate strongly depended on the composition of melt. Composition dependency of evaporation rate estimated from the activity of PbCl
2 for the PbO-PbCl
2 system generally represented the same trend, however the measured evaporation rate was larger than estimated one in the whole composition range. This result indicates that the formation of oxychloride melt affects the evaporation rate. Chlorination mechanisms and removal efficiency of Pb by chlorination have been discussed based on the present results.
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