Thermodynamic model of lead oxide activity in PbO-CaO-SiO2-FeO-Fe2O3 slag system
(1. School of Metallurgy and Chemical Engineering,
Jiangxi University of Science and Technology, Ganzhou 341000, China;
2. School of Metallurgy and Environment, Central South University, Changsha 410083, China)
Jiangxi University of Science and Technology, Ganzhou 341000, China;
2. School of Metallurgy and Environment, Central South University, Changsha 410083, China)
Abstract: According to the ion and molecule coexistence theory, a thermodynamic model of lead oxide activity in PbO-CaO-SiO2-FeO-Fe2O3 slag system was established at the temperature of 1273-1733 K. The activities of PbO in slag were calculated, and their equal activity curves were plotted. The influences of slag basicity Q, iron oxide rate R and temperature T on activity NPbO and activity coefficient γPbO were also investigated. Results show that the calculated values of γPbO are in good agreement with the reported experimental data, showing that the model can wholly embody the slag structural characteristics. NPbO departures positively from Raoult values, and increases with increasing PbO content in slag but changes little with T. γPbO increases with increasing Q, and goes through the maximum with increasing R for basic slag (Q>0.3). Results can be applied to the thermodynamic research and operational optimization of modern lead smelting technologies.
Key words: ion and molecule coexistence theory; thermodynamic model; lead oxide; activity