Fundamental experimental and thermodynamic modelling study in support of the lead battery recycling slag

Abstract

Antimony, tin, and other higher value metals, as well as elements such as arsenic and lead, can be found in the slags produced during the lead battery recycling process. Gopher Resources operates lead battery recycling furnaces that use sodium slag systems for which there has been less thermodynamic research than more common slag systems. Better thermodynamic information could help improve the process efficiency and control of these furnaces, as well as the recovery of higher value metals. The present study focuses on experimental research and thermodynamic modeling of slags belonging to the Na-Si-Fe-O system, with minor elements including S, Sb, Sn, Pb, and As. Examples of important systems studied extensively for the first time include Fe-Sb-Si-O and Na-Sn-Si-O. Phase equilibria methods are used to determine all the interaction parameters between the impurity metals and the main components of the slag. The experimental methodology involves equilibration, quenching, and electron-probe X-ray microanalysis of the samples. The modified Quasichemical model is used to describe the thermodynamics of the slags. The model also takes into account possible formation of matte/metal/speiss liquids, and numerous solid phases, which is important for understanding of fundamentals operation of various process units.