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reduction behavior OF IRON ORE PELLETS CONTAININGCARBON UNDER NON-ISOTHERMAL CONDITION

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Acta Metallurgica Sinica(English Letters) 2000年第5期13卷 1059-1067页

作者： X.M.Yang Y.S.Xie D.G.Wang D.B.Huang T.J.Yang L.T.Kong Institute of Chemical Metallurgy The Chinese Academy of Sciences Beijing 100080China University of Science and Technology Beijing Beijing 100083China

The reduction behavior of iron ore pellets containing carbon under non-isothermal condition in the temperature range from 573 to 1373 K was investigated in a laboratory scale setup. The test results show that carbon content has no obvious effect on reduction degree of composite pellets (C/O mole ratio=1.0) by CO in the temperature range from 573 to 1373 K under linear temperature-rising program; reduction degree of iron ore pellets containing carbon is large in 90%CO-10%CO2 mixture than that of in 100%CO atmosphere or in 80%CO-20%CO2 mixture; the s type temperature-rising program has a better effect than that of linear one in increasing the reduction degree; and reduction degree of slower linear temperature-rising program is greater than that of faster one, but the final reduction degrees, i.e., those at the highest temperature are about the same for various CO partial pressures or temperature-rising programs. The kinetic analysis also shows that the reduction of iron ore-carbon composite pellets by CO or CO-CO2 mixture under non-isothermal condition should be controlled by surface reaction, and the apparent reduction activation energy changes with the reduction progress under various test conditions.

关键词： iron ore pellet containing carbon reduction behavior kinetics activation energy non-isothermal

Comparison of reduction behavior of Fe_2O_3, ZnO and ZnFe_2O_4 by TPR technique

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Journal of Natural Gas Chemistry 2009年第1期18卷 110-113页

作者： Meisheng Liang Wenkai Kang Kechang Xie College of Environmental Science and Engineering Taiyuan University of Technology Key Laboratory for Coal Science and Technology of Shanxi Province and Ministry of Education Taiyuan 030024 Shanxi China The Second Design Institute of Chemical Industry Taiyuan 030002 Shanxi China

Advanced integrated gasification combined cycle （IGCC） power generation systems require the development of high-temperature, regenerable, desulfurization sorbents capable of removing hydrogen sulfide from coal gasifier gas to very low levels. As a sort of effective desufurizer, such as Fe2O3, ZnO and ZnFe2O4, it will endure strong reducing atmosphere in desulfurization process. The reduced degree of desufurizer can have an effect on its desulfurization reactivity. In this paper, Fe2O3, ZnO and ZnFe2O4 were synthesized by precipitation or co-precipitation at constant pH. After aging, washing and drying, the solids were calcined at 800℃. The reduction behaviors of sample were characterized by temperature-programmed reduction （TPR）. It is found that there are two reduction peaks for Fe2O3 in TPR, and whereas no reduction peaks for ZnO are found. The reduction process of ZnFe2O4 prepared by co-precipitation is different from that of Fe2O3. ZnFe2O4 is easier to be reduced than Fe2O3. The activation energy of reduction process for Fe2O3 and ZnFe2O4 is obtained at different reduction periods.

关键词： Fe2O3 ZnFe2O4 ZnO reduction behavior TPR

Effects of basicity and temperature on mineralogy and reduction behaviors of high-chromium vanadium-titanium magnetite sinters

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Journal of Central South University 2019年第1期26卷 132-145页

作者： TANG Wei-dong YANG Song-tao ZHANG Li-heng HUANG Zhuang YANG He XUE Xiang-xin School of Metallurgy Northeastern University School of Materials and Metallurgy University of Science and Technology Liaoning

The effects of basicity and temperature on the reduction process of Hongge high-chromium vanadium-titanium magnetite(HCVTM)sinter were investigated in this *** main characterization methods of X-ray fluorescence(XRF),X-ray diffraction(XRD),scanning electron microscope(SEM),and metallographic microscope were employed in this *** this work,the reduction of HCVTM sinter with different temperature and basicity were *** Fe,FeO,and TiO in reductive samples increase with increasing basicity and *** increase of basicity and temperature is favorable to the reduction of HCVTM *** Fe phase has out-migration tendency to the surface of sinter while the perovskite and silicate phases have in-migration tendency to the inside of *** reduction degradation index(RDI)decreases while the reduction index(RI)increases with increasing *** RI increases from 67.14%to 82.09%with increasing temperature from 1073 K to 1373 K.

关键词： basicity high-chromium vanadium-titanium magnetite sintering pot test mineralogy reduction behavior

STUDIES ON PRECIPITATED Cu-BASED CATALYST FOR METHANOL SYNTHESIS L REACTION CONDITION AND reduction PROCESS

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Journal of Energy Chemistry 1995年第4期 439-448页

作者： GUO Xian-Ji WANG Wen-Xiang LI FanDepartment of Chemistry. Zhengzhou University Zhengzhou. Henan 450052

A series of precipitated CuO-ZnO-AlOcatalysts for methanolsynthesis have been prepared and their catalytic activities under differentreaction conditions（temperature,pressure,space velocity）have been *** means of TPR,TG,the reduction behavior of typical catalyst sample andbinary sample CuO-AlOwas comparatively *** resultsindicate that the autocatalysis in reduction process of Cu-based catalystcorrelates with the CuO crystallinity.

关键词： Cu-based catalyst methanoi synthesis reduction behavior

behaviors of vanadium and chromium in coal-based direct reduction of high-chromium vanadium-bearing titanomagnetite concentrates followed by magnetic separation

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Transactions of Nonferrous Metals Society of China 2015年第4期25卷 1325-1333页

作者：赵龙胜王丽娜陈德胜赵宏欣刘亚辉齐涛中国科学院大学北京100049 中国科学院过程工程研究所湿法冶金清洁生产技术国家工程实验室北京100190 中国科学院过程工程研究所绿色过程与工程院重点实验室北京100190

The reduction behaviors of FeO·V2O3 and FeO·Cr2O3 during coal-based direct reduction have a decisive impact on the efficient utilization of high-chromium vanadium-bearing titanomagnetite concentrates. The effects of molar ratio of C to Fe n(C)/n(Fe) and temperature on the behaviors of vanadium and chromium during direct reduction and magnetic separation were investigated. The reduced samples were characterized by X-ray diffraction(XRD), scanning election microscopy(SEM) and energy dispersive spectrometry(EDS) techniques. Experimental results indicate that the recoveries of vanadium and chromium rapidly increase from 10.0% and 9.6% to 45.3% and 74.3%, respectively, as the n(C)/n(Fe) increases from 0.8 to 1.4. At n(C)/n(Fe) of 0.8, the recoveries of vanadium and chromium are always lower than 10.0% in the whole temperature range of 1100-1250 °C. However, at n(C)/n(Fe) of 1.2, the recoveries of vanadium and chromium considerably increase from 17.8% and 33.8% to 42.4% and 76.0%, respectively, as the temperature increases from 1100 °C to 1250 °C. At n(C)/n(Fe) lower than 0.8, most of the FeO·V2O3 and FeO·Cr2O3 are not reduced to carbides because of the lack of carbonaceous reductants, and the temperature has little effect on the reduction behaviors of FeO·V2O3 and FeO·Cr2O3, resulting in very low recoveries of vanadium and chromium during magnetic separation. However, at higher n(C)/n(Fe), the reduction rates of FeO·V2O3 and FeO·Cr2O3 increase significatly because of the excess amount of carbonaceous reductants. Moreover, higher temperatures largely induce the reduction of FeO·V2O3 and FeO·Cr2O3 to carbides. The newly formed carbides are then dissolved in the γ(FCC) phase, and recovered accompanied with the metallic iron during magnetic separation.

关键词： high-chromium vanadium-bearing titanomagnetite concentrates coal-based direct reduction magnetic separation reduction behavior vanadium chromium

Influence of basicity on metallurgical performances of fired super high-grade magnetite pellets in hydrogen-rich gases

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Journal of Iron and Steel Research International 2021年第10期28卷 1212-1222页

作者： Feng Zhang De-qing Zhu Jian Pan Zheng-qi Guo Meng-jie Xu College of Materials and Metallurgy Guizhou UniversityGuiyang550025GuizhouChina School of Minerals Processing and Bioengineering Central South UniversityChangsha410083HunanChina Sinosteel Equipment&Engineering Co. Ltd.Beijing100080China

The influence of basicity on the metallurgical performances and reduction characteristics of fired super high-grade magnetite pellets under the simulated shaft furnace gas conditions was *** fired pellets in the basicity range of 0.09(natural basicity)to 1.00 show superior reducibility and low-temperature disintegration ***,in the basicity range of 0.20–0.80,the abnormal swelling of the fired pellets *** basicity from 0.09 to 0.40 promotes the generation of low melting point slag phases and lower porosity of fired pellets,and accelerates the growth and densification of hematite crystals,impeding the reduction of hematite particles and the formation of metallic iron *** addition,the slags that distribute between the hematite particles absorb the reduction stresses by increased distances between the particles during the reduction process,which leads to the large reduction swelling of pellets.

关键词： Ultrafine high-grade magnetite concentrate Basicity Metallurgical performance reduction behavior Gas-based shaft furnace direct reduction Fired pellet

Support effect of the supported ceria-based catalysts during NH_3-SCR reaction

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Chinese Journal of Catalysis 2017年第8期38卷 1423-1430页

作者： Xiaojiang Yao Li Chen Tingting Kong Shimin Ding Qiong Luo Fumo Yang Collaborative Innovation Center for Green Development in Wuling Mountain Areas Yangtze Normal University Chongqing 408100 China Center for Excellence in Regional Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 Fujian China Research Center for Atmospheric Environment Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences Chongqing 400714 China School of Urban Construction and Environmental Engineering Chongqing University Chongqing 400045 China

To investigate how the physicochemical properties and NH3‐selective catalytic reduction(NH3‐SCR)performance of supported ceria‐based catalysts are influenced as a function of support type,a series of CeO2/SiO2,CeO2/γ‐Al2O3,CeO2/ZrO2,and CeO2/TiO2catalysts were *** physicochemical properties were probed by means of X‐ray diffraction,Raman spectroscopy,Brunauer‐Emmett‐Teller surface area measurements,X‐ray photoelectron spectroscopy,H2‐temperature programmed reduction,and NH3‐temperature programmed ***,the supported ceria‐based catalysts'catalytic performance and H2O+SO2tolerance were evaluated by the NH3‐SCR model *** results indicate that out of the supported ceria‐based catalysts studied,the CeO2/γ‐Al2O3catalyst exhibits the highest catalytic activity as a result of having a high relative Ce3+/Ce4+ratio,optimum reduction behavior,and the largest total acid site ***,the CeO2/γ‐Al2O3catalyst also presents excellent H2O+SO2tolerance during the NH3‐SCR process.

关键词： Support effect Supported ceria‐based catalyst reduction behavior Surface acidity Ammonia‐selective catalytic reduction

Analysis on Ammonia Synthesis over Wustite-Based Iron Catalyst

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Chinese Journal of Chemical Engineering 2003年第1期11卷 19-26页

作者：李小年刘化章岑亚青胡樟能 Instituteof Catalysis Zhejiang University of Technology Zhejiang Key Laboratory of Heterogeneous Catalysis

Wustite-based catalyst for ammonia synthesis exhibits extremely high activity and easy to reduction under a wide range of conditions. The reaction kinetics of ammonia synthesis can be illustrated perfectly by both the classical Temkin-Pyzhev and modified Temkin equations with optimized a of 0.5. The pre-exponent factors and activation energies at the pressures of 8.0 and 15.0MPa are respectively k0 = 1.09 x 1015, 7.35 X 1014Pa0.5.s-1, and E = 156.6, 155.5kJ-mol-1 derived from the classical Temkin-Phyzhev equation, as well as k0 = 2.45 X 1014, 1.83 X 1014Pa0.5s-1, and E = 147.7, 147.2kJ-mol-1 derived from the modified Temkin equation. Although the degree of reduction under isothermal condition is primarily dependent upon temperature, low pressure seems to be imperative for reduction under high temperature and low space velocity to be considered as a high activity catalyst. The reduction behavior with dry feed gas can be illustrated perfectly by the shrinking-sphere-particle model, by which the reduction-rate constants of 4248exp (-71680/KT) and 644exp (-87260/RT) were obtained for the powder (0.045-0.054mm) and irregular shape (nominal diameter 3.17 mm) catalysts respectively. The significant effect of particle size on reduction rate was observed, therefore, it is important to take into account the influence of particle size on reduction for the optimization of reduction process in industry.

关键词： wustite-based catalyst ammonia synthesis catalytic activity reduction behavior kinetics

Effect of temperature on suspension magnetization roasting of hematite using biomass waste as reductant:A perspective of gas evolution

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Journal of Central South University 2024年第6期31卷 1870-1887页

作者： CAO Yue SUN Yong-sheng HAN Yue-xin GAO Peng LI Yan-jun School of Resources and Civil Engineering Northeastern UniversityShenyang 110819China National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources Shenyang 110819China

The magnetization reduction of hematite using biomass waste can effectively utilize waste and reduce CO_(2) emission to achieve the goals of carbon peaking and carbon *** effects of temperatures on suspension magnetization roasting of hematite using biomass waste for evolved gases have been investigated using TG-FTIR,Py-GC/MS and gas composition *** mixture reduction process is divided into four *** the temperature range of 200-450℃ for mixture,the release of CO_(2),acids,and ketones is dominated in gases *** yield and concentration of small molecules reducing gases increase when the temperature increases from 450 to 900℃.At 700℃,the volume concentrations of CO,H_(2) and CH_(4) peak at 8.91%,8.90% and 4.91%,*** the suspension magnetization roasting process,an optimal iron concentrate with an iron grade of 70.86%,a recovery of 98.66% and a magnetic conversion of 45.70% is obtained at 700℃.Therefore,the magnetization reduction could react greatly in the temperature range of 600 to 700℃ owing to the suitable reducing *** study shows a detail gaseous evolution of roasting temperature and provides a new insight for studying the reduction process of hematite using biomass waste.

关键词： suspension magnetization roasting biomass pyrolysis gases evolution reduction behavior