Polarisation of Pure Iron in the Presence of Iron Sulphide Minerals

Polarisation studies of pure iron in the presence of five iron sulphide minerals (mackinawite, greigite pyrrhotite, marcusite and pyrite) showed thut these compounds effected both anodic and cathodic depolarisation. Goethite, an iron source for the iron sulphides, was completely inactive in this process. Biogenic samples of greigite and mackinawite were found to be less effective depolarising agents than chemically prepared samples. This was attributed to the presence of minor phases and dead bacterial cells in these specimens.