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Kinetics of reductive leaching of manganese oxide ore using cellulose as reductant 被引量:6
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作者 武芳芳 钟宏 +1 位作者 王帅 赖素凤 《Journal of Central South University》 SCIE EI CAS 2014年第5期1763-1770,共8页
The kinetics of reductive leaching of manganese from a low-grade manganese oxide ore were studied using cellulose as reductant in dilute sulfuric acid medium.It was found that when the stirring speed was higher than 2... The kinetics of reductive leaching of manganese from a low-grade manganese oxide ore were studied using cellulose as reductant in dilute sulfuric acid medium.It was found that when the stirring speed was higher than 200 r/min,the effect of gas film diffusion on manganese extraction efficiency could be neglected,and the kinetic behavior was investigated under the condition of elimination of external diffusion influence on the leaching process.Effects of leaching temperature,mass ratio of cellulose and ore,and the sulfuric acid concentration on manganese extraction efficiency were discussed.The kinetic data were analyzed based on the shrinking core model,which indicated that the leaching process was dominated by both ash layer diffusion and chemical reaction at the initial stage,with the progress of leaching reaction,the rate-controlling step switched to the ash layer diffusion.It was also concluded that the sulfuric acid concentration had the most significant influence on the leaching rate,the reaction orders with respect to the sulfuric acid concentration were 2.102 in the first 60 min,and 3.642 in the later 90 min,while the reaction orders for mass ratio of cellulose and ore were 0.660 and 0.724,respectively.An Arrhenius relationship was used to relate the temperature to the rate of leaching,from which apparent activation energies were calculated to be 46.487 kJ/mol and 62.290 kJ/mol at the two stages,respectively.Finally,the overall leaching rate equations for the manganese dissolution reaction with cellulose in sulphuric acid solution were developed.The morphological changes and mineralogical forms of the ore before and after the chemical treatment were discussed with the support of SEM and XRD analyses. 展开更多
关键词 manganese oxide ore: reductive leaching CELLULOSE KINETICS
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Manganese extraction from high-iron-content manganese oxide ores by selective reduction roasting-acid leaching process using black charcoal as reductant 被引量:10
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作者 张元波 赵熠 +3 位作者 游志雄 段道显 李光辉 姜涛 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第7期2515-2520,共6页
Reduction roasting-acid leaching process was utilized to process high-iron-content manganese oxide ore using black charcoal as reductant. The results indicate that, compared with the traditional reductant of anthracit... Reduction roasting-acid leaching process was utilized to process high-iron-content manganese oxide ore using black charcoal as reductant. The results indicate that, compared with the traditional reductant of anthracite, higher manganese extraction efficiency is achieved at lower roasting temperature and shorter residence time. The effects of roasting parameters on the leaching efficiency of Mn and Fe were studied, and the optimal parameters are determined as follows: roasting temperature is 650 °C, residence time is 40 min, and black charcoal dosage is 10%(mass fraction). Under these conditions, the leaching efficiency of Mn reaches 82.37% while that of Fe is controlled below 7%. XRD results show that a majority of MnO2 and Fe2O3 in the raw ore are reduced to MnO and Fe3O4, respectively. 展开更多
关键词 manganese ore reduction roasting acid leaching black charcoal
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Study on hydrometallurgical process and kinetics of manganese extraction from low-grade manganese carbonate ores 被引量:6
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作者 Liu Youcai Lin Qingquan +4 位作者 Li Lifeng Fu Jiangang Zhu Zhongsi Wang Chongqing Qian Dong 《International Journal of Mining Science and Technology》 SCIE EI 2014年第4期567-571,共5页
In order to utilize low-grade manganese ore resources effectively, a hydrometallurgical process was developed for manganese extraction in dilute sulfuric acid medium, and the kinetics of leaching manga- nese was also ... In order to utilize low-grade manganese ore resources effectively, a hydrometallurgical process was developed for manganese extraction in dilute sulfuric acid medium, and the kinetics of leaching manga- nese was also investigated. At room temperature, manganese from low-grade manganese carbonate ores was extracted by sulfuric acid leaching without reductants. During the extracting process, single-factor analysis method was used to evaluate the effects of grinding fineness, sulfuric acid concentration, liquid-to-solid ratio, agitation rate and leaching time on the leaching efficiencies of Mn and Fe. The optimal leaching conditions are determined as coarse particles of below 2 mm size (without ball-milling), sulfuric acid concentration of 0.86 mol/L, liquid-to-solid ratio of 5:1, agitation rate of 150 r/rain and leaching for 180 min at room temperature. Under the optimal conditions, the leaching efficiencies of Mn and Fe are 96.21g and 13.35%, respectively. In addition, through the experiments at different temper- atures, it is found that the leaching process follows the shrinking core model under the conditions of changing acid concentration and intermittent reaction device. Moreover, the apparent activations of effective diffusion and chemical reaction in the kinetic model are calculated to be 18.83 and 27.15 kJ/mol, respectively. 展开更多
关键词 Low-grade manganese ore leaching Kinetics Model
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P2-type layered high-entropy oxides as sodium-ion cathode materials 被引量:4
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作者 Junbo Wang Sören L Dreyer +15 位作者 Kai Wang Ziming Ding Thomas Diemant Guruprakash Karkera Yanjiao Ma Abhishek Sarkar Bei Zhou Mikhail V Gorbunov Ahmad Omar Daria Mikhailova Volker Presser Maximilian Fichtner Horst Hahn Torsten Brezesinski Ben Breitung Qingsong Wang 《Materials Futures》 2022年第3期171-184,共14页
P2-type layered oxides with the general Na-deficient composition Na_(x)TMO_(2)(x<1,TM:transition metal)are a promising class of cathode materials for sodium-ion batteries.The open Na+transport pathways present in t... P2-type layered oxides with the general Na-deficient composition Na_(x)TMO_(2)(x<1,TM:transition metal)are a promising class of cathode materials for sodium-ion batteries.The open Na+transport pathways present in the structure lead to low diffusion barriers and enable high charge/discharge rates.However,a phase transition from P2 to O2 structure occurring above 4.2 V and metal dissolution at low potentials upon discharge results in rapid capacity degradation.In this work,we demonstrate the positive effect of configurational entropy on the stability of the crystal structure during battery operation.Three different compositions of layered P2-type oxides were synthesized by solid-state chemistry,Na_(0.67)(Mn_(0.55)Ni_(0.21)Co_(0.24))O_(2),Na_(0.67)(Mn_(0.45)Ni_(0.18)Co_(0.24)Ti_(0.1)Mg_(0.03))O_(2) and Na_(0.67)(Mn_(0.45)Ni_(0.18)Co_(0.18)Ti_(0.1)Mg_(0.03)Al_(0.04)Fe_(0.02))O_(2) with low,medium and high configurational entropy,respectively.The high-entropy cathode material shows lower structural transformation and Mn dissolution upon cycling in a wide voltage range from 1.5 to 4.6 V.Advanced operando techniques and post-mortem analysis were used to probe the underlying reaction mechanism thoroughly.Overall,the high-entropy strategy is a promising route for improving the electrochemical performance of P2 layered oxide cathodes for advanced sodium-ion battery applications. 展开更多
关键词 P2-type layered cathode high-entropy oxides sodium-ion battery gassing behavior manganese leaching
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