Corrosion of mild steel in porous media

The corrosion process in large-particle porous media is investigated with particular reference to corrosion in bulk carriers (ships). Examples of large-particle porous media include raw materials such as coal and iron ore which typically have particle sizes ranging up to approximately 50 mm diameter. It is proposed that the corrosion process is dominated by finer particles which co-exist with the larger particles. A mathematical model of the corrosion process is developed and used to estimate corrosion rates. These are shown to compare well with experimental results. The analysis indicates that to minimise corrosion it is desirable to maintain the moisture content of porous media in contact with mild steel either to less than 50%, or to more than 80%, of the maximum water holding capacity of the media.