Experimental study, thermodynamic calculations and industrial implications of slag/matte/metal equilibria in the Cu–Pb–Fe–O–S–Si system

Abstract

Present work is a part of the series of the integrated experimental and modelling studies aimed at better prediction of the conditions of matte formation in the pyrometallurgical processing of lead (Pb) during the oxidative smelting and slag reduction conditions. Experiments involved high-temperature equilibration of samples within the Cu–Pb–Fe–O–S–Si system, targeting the formation of slag, matte, metal and tridymite phases. Compositions of phases in quenched samples were determined using electron probe X-ray microanalysis (EPMA). New experimental results were used together with earlier data from literature to develop the combined thermodynamic database. Main phases were described using two separate solutions: slag solution was developed within the framework of Modified Quasichemical Model in Quadruplet Approximation, while matte/metal solution used the Modified Quasichemical Model in Pair Approximation. An example of the processing of primary and secondary complex lead-copper-containing materials in electric furnace at Aurubis, was used to demonstrate the application of the thermodynamic database. Calculations were performed within the Cu–Pb–Fe–O–S–Si–(Al, Ca, Mg, Zn, As) chemical system using FactSage software. The database also works within the environment of ChemApp, ChemSheet and SimuSage software packages.

Keywords

• FactSage
• Lead slag
• Lead matte
• Cu–Pb separation