Computational Thermodynamics Modeling of Minor Element Distributions During Copper Flash Converting

Continuous copper converting processes are replacing traditional Peirce-Smith converters because they overcome most of the difficulties associated with this old batch technology. Most notably, they offer much improved environmental control of emissions. The Kennecott-Outotec flash converting process is attractive because it decouples smelting and converting, as well as offers high levels of sulfur capture. The success of a copper smelter depends on the way it controls the many minor elements that enter with the concentrate feed, and an understanding of the factors that control minor element distributions is essential. In this work, a computational thermodynamics model of the flash converter was developed and validated against published performance data. It was then used to predict the distribution behavior of lead, arsenic, bismuth, and cadmium, and the results matched the published data closely. It is suggested that the flash converter can be considered to approximate an equilibrium reactor and that minor elements distribute between the phases in a way that depends mostly on their thermodynamic properties.