The effect of temperature and ionic strength on iron carbonate (FeCO3) solubility limit

In CO2 corrosion, precipitation of iron carbonate can significantly reduce the corrosion rate of the underlying steel. Precipitation rate depends on a reliable calculation of the iron carbonate solubility limit. The open literature does not provide an expression for iron carbonate solubility that covers a wide enough range of parameters. In this study a unified iron carbonate solubility (Ksp in mol2/L2) expression is developed based on the literature data: logKsp=-59.3498-0.041377Tk-2.1963Tk+24.5724log(Tk)+2.518I0.5-0.657I which accounts for both temperature and ionic strength effects. The predictions made with this unified equation agree well with the published experimental data.