Abstract
The process chemistries of pyrometallurgical processes are becoming increasingly complex; computational tools capable of predicting the phase equilibria, and the mass and energy balance of the multicomponent slag/metal/matte/speiss/gas system are required for optimising the operation of existing and the development of novel processes.
In the present study, the phase equilibria of the PbO-ZnO-FeO-FeO1.5-SiO2-MgO system in equilibrium with metal or air were studied using the equilibration and quenching technique, followed by the use of electron probe X-Ray microanalysis (EPMA) to measure the phase assemblages and compositions of equilibrated samples. The newly obtained experimental phase equilibria data addressed gaps and inconsistencies in the available literature data and were used for the optimisation of thermodynamic model parameters describing the complex multicomponent system.
The present work was part of the integrated experimental and thermodynamic modelling research program on the phase equilibria of the Cu-Pb-Fe-Zn-Ca-Si-O-S-Al-Mg-Cr-Sn-Sb-Bi-Ag-Au-Ni-Co slag/metal/matte/speiss system. The applicability of the research program results to modern industrial needs was demonstrated by the development of the mass and energy balance of a zinc slag fuming process which uses ammonia as a carbon-free alternative to the conventionally used coal fuel and reducing agent.