Potentiodynamic polarization study of the corrosion characteristics of acid mine drainage

Potentiodynamic tests were carried out to evaluate the attacking characteristics of acid mine drainage (AMD) from South African mines. Tests were done using seven solutions of:- AMD water taken from the field and consisting of two AMD sources from the gold mines and two sources from the coal mines; sulphuric acid, distilled water, synthetic AMD prepared in the laboratory. Tests were done at normal room temperature of 23oC using mild steel and stainless steel samples. Tafel plots were generated and corrosion current (Icorr), corrosion potential (Ecorr), corrosion rates determined in each case. The corrosion rate of AMD from the coal mines was found to be similar to the corrosion of AMD from the gold tailings dam mine, both of which were significantly higher than the corrosion of AMD from the underground gold mine. It is, however, anticipated that the corrosion bevaviour could be different under static conditions and further investigations in this regard are being conducted