Pure manganese dioxide was successfully produced from low grade pyrolusite ore (beta-MnO2) and sulphur slag. First, the reduction of beta-MnO2, introduced as pure pyrolusite was studied using different ratios of elemental sulphur at different temperature (300-400 degreesC), in air or in closed stainless tube. The reduction process was followed by leaching of Mn with H2O. 0.1, 0.5 or 1 M H2SO4. beta-MnO2 was found to undergo a reduction process at obviously low temperature giving Mn3O4, MnS and MnSO4 depending on the applied conditions. The efficiency of Mn leaching ranged from 40 to 99%. The optimum conditions of reduction and leaching were applied to low grade pyrolusite from Um Bogma. Sinai and sulphur slag remained from the sulphuric acid industry. MnSO4 was prepared by concentrating the liquor extract. gamma-MnO2 was produced either by precipitation from the liquor extract using ammonium peroxodisulphate or by electrodeposition on platinum anode. The products were characterised by X-ray diffraction, thermal and chemical analysis. (C) 2002 Elsevier Science B.V. All rights reserved.