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Influence of flux additives on iron ore oxidized pellets

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Journal of Central South University 2010年第4期17卷 732-737页

作者：范晓慧甘敏姜涛袁礼顺陈许玲 School of Resources Processing and Bioengineering Central South University

Six additives,i.e.,limestone,lime,magnesite,magnesia,dolomite and light-burned-dolomite,were added for investigating their influences on the pellet *** green balls,adding lime and light-burned-dolomite makes the wet drop strength decrease firstly,and then increase with further increase of additive ***(OH)2 affects the bentonite properties at the beginning,but the binding property of Ca(OH)2 will be main when the dosage is *** other four additives decrease the drop strength for their disadvantageous physical *** preheated pellets,no mater what kind of additive is added,the compressive strength will be decreased because of unmineralized *** roasted pellets,calcium additives can form binding phase of calcium-ferrite,and suitable liquid phase will improve recrystallization of hematite,but excessive liquid will destroy the structure of pellets,so the compressive strength of pellet increases firstly and then *** adding magnesium additives,the strength will be decreased because of the oxidation of magnetite retarded by MgO.

关键词： iron ore additives oxidized pellets compressive strength

Direct reduction of carburized pre-reduced pellets by microwave heating

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Journal of Central South University 2014年第1期21卷 351-357页

作者：胡兵黄柱成易凌云姜涛 School of Minerals Processing and Bioengineering Central South University Zhongye Changtian International Engineering Co. Ltd.

A new iron-making process using carburized pre-reduced iron ore pellets and microwave heating is investigated. The pre-reduced pellets, with a porous structure, and fine particles are carburized homogeneously at 400-650 ℃ in a CO atmosphere. The carburized carbon not only acts reaction as a reduction agent, but also absorbs microwave in the reduction process. Hence, the carburized pre-reduced pellets can be rapidly reduced by microwave heating. There are three procedures involved in the process, namely, gas-based pre-reduction, low-temperatttre carburization and deep reduction by microwave heating. Carburized pre-reduced iron ore pellets show a rapid temperature rise that is twice as fast as the results for pre-reduced pellets in the laboratory. This not only improves the efficiency of the microwave heating, but also accelerates the reduction of iron oxides. The temperature of the pre-reduced pellets rises to 1050 ℃ in 45 min when the carburization rate is 2.02%, and the metallization rate and compressive strength reach 94.24% and 1725 N/pellet, respectively.

关键词： oxidized pellets pre-reduction carburizing microwave heating direct reduction

Characteristics of humin fractions associated with inorganic minerals obtained by NaOH,and NaOH assisted with anthraquinone extraction procedures

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Journal of Central South University 2012年第8期19卷 2286-2290页

作者：韩桂洪姜涛黄艳芳张元波李光辉 School of Minerals Processing and Bioengineering Central South University

The differences in XRD patterns, elemental compositions, FT-IR spectra and TG-DSC curves of extract residues obtained by NaOH, and NaOH assisted with anthraguinone （AQ） extraction procedures were studied. The extract residues are mainly comprised of humin fractions associated with inorganic minerals. XRD analysis shows that there is no typical peak of organic carbon because those organic humin fractions appear as a highly disordered substance. The peak of quartz is dominant. The elementary analysis shows that assistant AQ in NaOH solution can break the link of organic humic substances with inorganic minerals. And aromatization degree of humin fractions obtained by NaOH is smaller than that obtained by NaOH assisted with AQ. FT-IR analysis displays that various groups exist in those two humin fractions obtained by different extraction procedures. There are some differences in FT-IR curves between two humin fractions. TG-DSC analysis shows that thermal decomposition occurs during the heating of testing samples. By contrast, the humin fractions associated with inorganic minerals obtained by NaOH possess a higher thermal decomposition range.

关键词： organic binder humin fraction infrared spectrum oxidized pellets