2009 Volume 50 Issue 6 Pages 1457-1461
The equilibration of a Ag-Pb-based melt with PbO-NaO0.5 and PbO-CaO melts at 1273 K was investigated. A chemical equilibrium technique was used to carry out measurements. The oxygen partial pressure was measured by an electromotive force (EMF) method. The activity coefficient of AgO0.5 in the PbO-NaO0.5 and PbO-CaO melts and that of PbO in the PbO-NaO0.5 melt was derived. The addition of NaO0.5 to the PbO-based melt resulted in a slight decrease in the activity coefficient of AgO0.5. However, the activity coefficient of PbO decreased remarkably with an increase in the concentration of NaO0.5 in the PbO-based melt. Therefore, improved phase separation of Ag from the PbO-based melt was achieved by the addition NaO0.5. The addition of CaO in the PbO-based melt did not cause any change in the activity coefficient of AgO0.5.
