Precise regulation of the phase transformation for pyrolusite during the reduction roasting process  

作　　者：Ruofeng Wang Peng Gao Shuai Yuan Yanjun Li Yingzhi Liu Cheng Huang 

机构地区：[1]School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China [2]National-Local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources,Shenyang 110819,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2024年第1期81-90,共10页矿物冶金与材料学报（英文版）

基　　金：financially supported by the National Key Research and Development Program of China (No.2023YFC2909000);the National Natural Science Foundation of China(No.52174240);the Open Foundation of State Key Laboratory of Mineral Processing (No.BGRIMM-KJSKL-2023-15)。

摘　　要：The mechanism involved in the phase transformation process of pyrolusite (MnO_(2)) during roasting in a reducing atmosphere was systematically elucidated in this study,with the aim of effectively using low-grade complex manganese ore resources.According to single-factor experiment results,the roasted product with a divalent manganese (Mn^(2+)) distribution rate of 95.30% was obtained at a roasting time of 25 min,a roasting temperature of 700℃,a CO concentration of 20at%,and a total gas volume of 500 mL·min^(-1),in which the manganese was mainly in the form of manganosite (MnO).Scanning electron microscopy and Brunauer–Emmett–Teller theory demonstrated the microstructural evolution of the roasted product and the gradual reduction in the pyrolusite ore from the surface to the core Thermodynamic calculations,X-ray photoelectron spectroscopy,and X-ray diffractometry analyses determined that the phase transformation of pyrolusite followed the order of MnO_(2)→Mn_(2)O_(3)→Mn_(3)O_(4)→MnO phase by phase,and the reduction of manganese oxides in each valence state proceeded simultaneously.

关 键 词：PYROLUSITE phase transformation reduction roasting microstructural evolution reaction mechanism 

分 类 号：TF046.2[冶金工程—冶金物理化学]