Magnetite Anodes for Deep Well Groundbeds

Abstract Today there are several types of materials available for the design and installation of impressed current anode groundbeds. Materials such as Magnetite, FeSi, FeSiCr and Mixed Metal Oxide coated titanium are being used on a regular basis in anode production. From those anodes mentioned above, Magnetite anodes are currently being used very successfully in Europe, North Africa and the Middle East and various other world locations and applications over the last 30 years. They are used for installation in both soil and seawater as well as for high current application as in deep well groundbeds. This paper is based upon various case studies of large scale applications and shows the specific requirements for anode systems which have been installed under conditions where the soil and/or water contain a high chlorine concentration as is often found in many desert areas, especially in North Africa and the Middle East. The anodic reaction (2Cl- - 2e- = Cl2) which occurs around the anode when it is installed in such acid saline solutions causes chlorine gas production at the anode / electrolyte interface and also a high chlorine gas concentration around the anodes and its components. The presence of chlorine gas is one of the major reasons for an anode groundbed failure. This paper concentrates on the known threats in relation to anode groundbed systems as well as covering the recent developments in improving and optimizing the reliability of the Magnetite anode systems, which in turn improves the required real lifetime expectations of the anode groundbed system.