Manganese leaching in the FeS2–MnO2–O2–H2O system at high temperature in an autoclave

Efficiency and sustainable leaching process of manganese from pyrolusite-pyrite mixture in sulfuric acid systems enhanced by microwave heating

“…Since manganese dioxide (MnO2) is stable under acidic or alkaline conditions, acidic manganese extraction from pyrolusite needs to be carried out under reduction conditions. Therefore, the use of a reducing agent is essential [9]. Combined with the theoretical calculation of Fig.…”

“…It should be mentioned that two main methods are used to recover manganese resources: pyrometallurgy and hydrometallurgy [7]. Although pyrometallurgy has the advantage since it provides a decent recovery rate and is more efficient, it also has disadvantages such as high energy consumption and high pollution during the recovery process; thus, hydrometallurgy is focused on the aspect of environmental protection for the recovery of low-grade minerals [8,9]. Since the manganese in low-grade pyrolusite usually exists in the form of insoluble Mn 4+ , it is necessary to add a reducing agent to assist the leaching process [10].…”

Kinetics of acid leaching of high Ca and Si manganese ores by experiments and CFD simulation in dual impeller stirred tank

“…The results show that there is a high probability of reaction in some active sites on the surface of manganese dioxide, and the reaction rate is controlled by the surface diffusion of iron ions. Vracar and Cerovic [2] studied the mechanism of FeS2-MnO2-O2-H2O under high temperature conditions and the results showed that the oxidation rate of FeS2 and the leaching reaction rate of MnO2 were both first-order reactions, thus corresponding to the activation energy of unoxidized pyrite is 65 kJ.mol À1 , and unleached manganese is 97 kJ.mol À1 . Elsherief [3] studied the electric leaching process of manganese ore, and concluded that manganese dioxide was easily dissolved in acidic solution with low potential; meanwhile temperature played an important role in the leaching of manganese ore. Gamini Senanayake [4] leach manganese dioxide by reducing sulfuric acid, and obtain the surface reaction kinetic model.…”

Kinetic Study of the Leaching of Low-Grade Manganese Ores by Using Pretreated Sawdust as Reductant

“…Manganese can be treated by direct acid leaching under reducing conditions. Several inorganic reductants generally employed in acidic media are FeSO 4 [3,4], H 2 O 2 [5], SO 2 [6], and sulfide [7,8]. However, some of these reducing agents, such as SO 2 , may be harmful to the environment, and FeSO 4 may result in a high content of iron in the leaching solution.…”