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

Abstract

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 Fe304 in the reaction products, detected by DTA, indicates that the SO2 is initially oxidized to SO 3 by reducing MnO2, Mn203 and Fe203 to MnO and Fe30,. SO3 finally attacks MnO to form MnSO,. 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.When intimate mixtures of pyrite (FeS2) and pyrolusite (MnO2) are reacted at high temperatures, about 80% of the Mn is converted to MnSO 4 in a period of 7 hrs [1]. A higher yield (92%) is obtained when MnO 2 is directly reacted with SO 2, but the amount of SO 2 used is high [2]. In view of this, the DTA technique was used to study the changes that take place'in pyrite and pyrolusite during their reaction at high temperatures, and optimization studies were undertaken to fix the minimum time and temperature of reaction at which the maximum yield of pure MnSO, could be obtained.

Densification of MnSO4 ceramics by Cool-SPS: Evidences for a complex sintering mechanism and magnetoelectric coupling

“…However, the emergence of new sintering techniques opens opportunities to densify and study these thermodynamically fragile materials (referred to as fragile materials in the following). In the present work, we relied on the spark plasma sintering (SPS) technique for the densification of MnSO4 which displays a helical magnetic structure at low temperature (TN=11K) [15] but decomposes at 780°C [16].…”