DTA studies on preparation of MnSO4 by reacting pyrite and pyrolusite at high temperatures

The preparation of MnSO₄ by reacting pyrolusite at high temperatures with SO₂ generated from pyrite was followed by DTA, and the process conditions were optimized to fix the minimum time and temperature of reaction required to obtain the maximum yield of pure MnSO₄ from stoichiometric amounts of reactants in a natural draught of air. The presence of MnO and Fe₃O₄ in the reaction products, detected by DTA, indicates that the SO₂ is initially oxidized to SO₃ by reducing MnO₂, Mn₂O₃ and Fe₂O₃ to MnO and Fe₃O₄. SO₃ finally attacks MnO to form MnSO₄. When an intimate stoichiometric blend of pyrite and pyrolusite is heated at temperatures ranging from 873 K to 973 K for 3 hrs, about 93% of the Mn is converted to ironfree MnSO₄.