Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by sphalerite ((Zn, Fe) S)was
examined during its grinding process. It was observed that sphalerite generated H2O2 in pulp liquid during wet
grinding and also when the freshly ground solids placed in water immediately after dry grinding. The generation
of H2O2 in either wet or dry grinding was thought to be due to a reaction between sphalerite and water where the
mineral surface is catalytically active to produce •OH free radicals by breaking down the water molecule. Effect of
pH on the formation of H2O2 by sphalerite showed that acidic pH values generated more H2O2.Mixtures of pyrite,
chalcopyrite and galena with sphalerite on the formation of H2O2 were also probed.