摘要
Pyrolusite comprises the foremost manganese oxides and is a major source of manganese production.An innovative hydrogenbased mineral phase transformation technology to pyrolusite was proposed,where a 96.44%distribution rate of divalent manganese(Mn^(2+))was observed at an optimal roasting temperature of 650℃,a roasting time of 25 min,and an H2 concentration of 20vol%;under these conditions.The manganese predominantly existed in the form of manganosite.This study investigated the generation mechanism of manganosite based on the reduction kinetics,phase transformation,and structural evolution of pyrolusite and revealed that high temperature improved the distribution rate,and the optimal kinetic model for the reaction was the random nucleation and growth model(reaction order,n=3/2)with an activation energy(E_(a))of 24.119 kJ·mol^(−1).Throughout the mineral phase transformation,manganese oxide from the outer layer of particles moves inward to the core.In addition,pyrolusite follows the reduction sequence of MnO_(2)→Mn_(2)O_(3)→Mn_(3)O_(4)→MnO,and the reduction of manganese oxides in each valence state simultaneously proceeds.These findings provide significant insight into the efficient and clean utilization of pyrolusite.
基金
supported by the National Key Research and Development Program of China(No.2023YFC 2909000)
the National Natural Science Foundation of China(No.52174240)
the Major Science and Technology Projects of Xinjiang Uygur Autonomous Region(No.2023A03003-2)
the XingLiao Talent Program of Liaoning Province(No.XLYC2203167)
the Excellent Youth Fund Project of Liaoning Natural Science Foundation(No.2023JH3/10200010)
the Fundamental Research Funds for the Central Universities(No.N23011026)
the Open Foundation of State Key Laboratory of Mineral Processing(No.BGRIMM-KJSKL-2023-15).
