Mechanochemical transformation of pyrolusite via manganese reduction

The effects of dry grinding, in air, of pyrolusite (beta-MnO2) are examined and the changes in the oxidation states of manganese during the process and the structural transformations that result from the treatment are studied. The ground product is examined by X-ray powder diffraction, infrared absorption spectroscopy, surface area and chemical analysis. According to preliminary results, oxygen loss is the most plausible mechanism to explain the reduction of manganese during the grinding process, which may lead to non-stoichiometric manganese oxide phases. 14 refs.