The CO2 capture and storage (CCS) technology is receiving increasing attention, as the need to reduce the emissions of greenhouse gases e.g. CO2, and CH4. CO2. These gases present in the process streams are highly corrosive towards carbon steel potentially causing a major problem in the industry. The occurrence of corrosion on the steel pipe will lead to significant production losses and costly shutdowns. Precipitated FeCO3 will deposit on the steel surface and create a protective barrier for further corrosion of pipelines and equipment. To predict the corrosion product, we need to understand the solubility of FeCO3 at different process parameters e.g. temperature, pressure, CO2 concentration and salinity. The solubility of FeCO3 is not well described in the literature. The overall objective of this work is to create a new fundamental understanding of FeCO3 solubility which will lead to better corrosion models, better prediction of corrosion rate, and better understanding of scale formation kinetics. The aim is to determine the FeCO3 solubility at different parameters; temperature, pressure, CO2 concentration, and in amine solutions. FeCO3 is not commercially available and must be synthesised under anoxic conditions before solubility measurement can be conducted.