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Upgrading and dephosphorization of Western Australian iron ore using reduction roasting by adding sodium carbonate

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 505-513页

作者： De-qing Zhu Tie-jun Chun Jian Pan Li-ming Lu Zhen He School of Minerals Processing and Bioengineering Central South University Commonwealth Scientific and Industrial Research Organisation (CSIRO)

The technology of direct reduction by adding sodium carbonate （Na2CO3） and magnetic separation was developed to treat Western Australian high phosphorus iron ore. The iron ore and reduced product were investigated by optical microscopy and scanning electron microscopy. It is found that phosphorus exists within limonite in the form of solid solution, which cannot be removed through traditional ways. During reduction roasting, Na2CO3 reacts with gangue minerals （SiO2 and A1203）, forming aluminum silicate-containing phosphorus and damaging the ore structure, which promotes the separation between iron and phosphorus during magnetic separation. Meanwhile, Na2CO3 also improves the growth of iron grains, increasing the iron grade and iron recovery. The iron concentrate, assaying 94.12wt% Fe and 0.07wt% P at the iron recovery of 96.83% and the dephosphorization rate of 74.08%, is obtained under the optimum conditions. The final product （metal iron powder） after briquetting can be used as the burden for steelmaking by an alactrie *** furnace to rer）la,ce scrar） steel.

关键词： iron ore reduction sodium carbonate ore roasting magnetic separation phosphorus removal

Effect of reduction roasting by using bio-char derived from empty fruit bunch on the magnetic properties of Malaysian iron ore

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International Journal of Minerals,Metallurgy and Materials 2014年第4期21卷 326-330页

作者： Nurul A.Yunus Mohd H.Ani Hamzah M.Salleh Rusila Z.A.Rashid Tomohiro Akiyama Hadi Purwanto Nur E.F.Othman Faculty of Engineering International Islamic University Malaysia Center for Advanced Research of Energy and Materials Faculty of EngineeringHokkaido University

Beneficiation of Malaysian iron ore is becoming necessary as iron resources are depleting. However, the upgrading process is challenging because of the weak magnetic properties of Malaysian iron ore. In this study, bio-char derived from oil palm empty fruit bunch （EFB） was utilized as an energy source for reduction roasting. Mixtures of Malaysian iron ore and the bio-char were pressed into briquettes and subjected to reduction roasting processes at 873-1173 K. The extent of reduction was estimated on the basis of mass loss, and the mag-netization of samples was measured using a vibrating sample magnetometer （VSM）. When reduced at 873 K, the original goethite-rich ore was converted into hematite. An increase in temperature to 1073 K caused a significant conversion of hematite into magnetite and enhanced the magnetic susceptibility and saturation magnetization of samples. The magnetic properties diminished at 1173 K as the iron ore was par-tially reduced to wustite. This reduction roasting by using the bio-char can assist in upgrading the iron ore by improving its magnetic proper-ties

关键词： iron ores ore reduction ore roasting bio-char magnetic properties

Thermodynamics and kinetics of alumina extraction from fly ash using an ammonium hydrogen sulfate roasting method

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International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 144-149页

作者： Ruo-chao Wang Yu-chun Zhai Zhi-qiang Ning School of Materials and Metallurgy Northeastern University

A novel method was developed for extracting alumina （Al2O3） from fly ash using an ammonium hydrogen sulfate （NH4HSO4） roasting process, and the thermodynamics and kinetics of this method were investigated. The thermodynamic results were verified experi-mentally. Thermodynamic calculations show that mullite present in the fly ash can react with NH4HSO4 in the 298-723 K range. Process op-timization reveals that the extraction rate can reach up to 90.95% when the fly ash reacts with NH4HSO4 at a 1：8 mole ratio of Al2O3/NH4HSO4 at 673 K for 60 min. Kinetic analysis indicates that the NH4HSO4 roasting process follows the shrinking unreacted core model, and inner diffusion through the product layer is the rate-controlling step. The activation energy is calculated to be 16.627 kJ/mol;and the kinetic equation can be expressed as 1-（2/3）α-（1-α）2/3=0.0374t exp[-16627/（RT）], whereαis the extraction rate and t is the roasting temperature.

关键词： ammonium hydrogen sulfate ore roasting fly ash alumina thermodynamics kinetics

Fluidized roasting reduction kinetics of low-grade pyrolusite coupling with pretreatment of stone coal

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International Journal of Minerals,Metallurgy and Materials 2013年第3期20卷 221-227页

作者： Ya-li Feng Zhen-lei Cai Hao-ran Li Zhu-wei Du Xin-wei Liu School of Civil and Environmental Engineering University of Science and Technology Beijing State Key Laboratory of Biochemical Engineering Institute of Process Engineering Chinese Academy of Sciences

Based on the fluidized roasting reduction technology of low-grade pyrolusite coupling with pretreatment of stone coal, the manganese reduction efficiency was investigated and technical conditions were optimized. It is found that the optimum manganese reduction efficiency can be up to 98.97% under the conditions that the mass ratio of stone coal to pyrolusite is 3：1, the roasting temperature of stone coal is 1000℃, the roasting temperature of pyrolusite is 800℃, and the roasting time is 2 h. Other low-grade pyrolusite ores in China from Guangxi, Hunan, and Guizhou Provinces were tested and all these minerals responded well, giving -99% manganese reduction efficiency. Meanwhile, the reduction kinetic model has been established. It is confirmed that the reduction process is controlled by the interface chemical reaction. The apparent activation energy is 36.397 kJ/mol.

关键词： pyrolusite ore roasting ore reduction fluidized beds kinetics stone coal

Effects of the mineral phase and valence of vanadium on vanadium extraction from stone coal

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International Journal of Minerals,Metallurgy and Materials 2012年第10期19卷 893-898页

作者： Yang-jia Hu Yi-min Zhang Shen-xu Bao Tao Liu College of Resources and Environmental Engineering Wuhan University of Technology Wuhan 430070 China Hubei Key Laboratory of Mineral Resources Processing and Environment Wuhan 430070 China

The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when the raw ore is leached by 4 moUL H2SO4 at 90℃ for 2 h. After the sample is roasted at 900℃ for 2 h, the leaching rate of vanadium reaches the maximum, and more than 70% of vanadium can be leached. The crystal of vanadium-bearing mica minerals decomposes and the Content of V（V） increases with the rise of roasting temperature from 600 to 900℃, therefore the leaching rate of vanadium increases significantly with the decomposition of the mica minerals. Some new phases, anorthite for example, form when the roasting temperature reaches 1000℃. A part of vanadium may be enwrapped in the sintered materials and newly formed phases, which may impede the oxidation of low valent vanadium and make the leaching rate of vanadium drop dramatically. The leaching rate of vanadium is not only determined by the valence state of vanadium but also controlled by the decomposition of vanadium-bearing minerals and the existence state of vanadium to a large extent.

关键词： vanadium metallurgy stone coal leaching ore roasting