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Calcium ferrite formation characteristic during iron ore sintering with different oxygen atmospheres

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Journal of Central South University 2014年第8期21卷 3043-3048页

作者：毛晓明游志雄张元波范振宇李光辉姜涛 School of Minerals Processing & Bioengineering Central South University

It is generally known that the large formation amount of calcium ferrite is favorable for the iron ore sintering. The effects of sintering temperature and O2 content of inlet gas on the calcium ferrite formation characteristic of typical iron ores, including hematite, limonite, specularite and magnetite, were investigated. And the effect of O2 content on the microstructure of the roasted briquettes was also studied in detail. The results show the amount of calcium ferrite initially increases then decreases with the increase of the sintering temperature. The temperature of maximum calcium ferrite generation amount is determined as follows： for hematite and limonite it is 1275 ~C, whereas for specularite and magnetite, 1250℃. The maximum contents of calcium ferrite for hematite, limonite, specularite and magnetite under the optimal sintering temperature are 73%, 82%, 67% and 63%, respectively. Increasing O2 content of the airflow is advantageous to the formation of calcium ferrite. Relatively, the effect of O2 content on the calcium ferrite formation of magnetite is the most pronounced, while O2 content of inlet gas has little effect on the calcium ferrite formation of limonite.

关键词： iron ore sintering calcium ferrite mineralization

The occurrences and geochemical characteristics of thorium in iron ore in the Bayan Obo deposit, Northern China

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Acta Geochimica 2020年第1期39卷 139-154页

作者： Xiaozhi Hou Zhanfeng Yang Zhenjiang Wang Wencai Wang Mining Research Institute Inner Mongolia University of Science and TechnologyBaotou 014010China Rare Earth Research and the Comprehensive Utilization State Key Laboratory of Bayan Obo Baotou 014000China Baotou Rare Earth Research Institute Baotou 014000China

The Bayan Obo deposit in northern China is an ultra-large Fe–REE–Nb *** occurrences,and geochemical characteristics of thorium in iron ores from the Bayan Obo Main ore Body were examined using chemical analysis,field emission scanning electron microscopy,energy dispersive spectrometer,and automatic mineral analysis *** identified that 91.69%of ThO2 in the combined samples was mainly distributed in rare earth minerals(bastnaesite,huanghoite,monazite;56.43%abundance in the samples),iron minerals(magnetite,hematite,pyrite;20.97%),niobium minerals(aeschynite;14.29%),and gangue minerals(aegirine,riebeckite,mica,dolomite,apatite,fluorite;4.22%).An unidentified portion(4.09%)of ThO2 may occur in other niobium minerals(niobite,ilmenorutile,pyrochlore).Only a few independent minerals of thorium occur in the iron ore *** mainly occurs in rare earth minerals in the form of isomorphic *** of the geochemical characteristics of the major elements indicate that thorium mineralization in the Main ore Body was related to alkali metasomatism,which provided source material and favorable porosity for hydrothermal *** elements such as Sc,Nb,Zr,and Ta have higher correlation coefficients with thorium,which resulted from being related to the relevant minerals formed during thorium *** addition,correlation analysis of ThO2 and TFe,and REO and TFe in the six types of iron ore samples showed that ThO2 did not always account for the highest distribution rate in rare earth minerals,and the main occurrence minerals of ThO2 were closely related to iron ore types.

关键词： Thorium Occurrence state Distribution law Geochemical characteristics iron ore Bayan Obo deposit

Reduction of 1-3 mm iron ore by CO on Fluidized Bed

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Journal of iron and Steel Research International 2011年第3期18卷 1-5页

作者： PANG Jian-ming GUO Pei-min ZHAO Pei The State Key Laboratory for Advanced Steel Processes and Products Central Iron and Steel Research InstituteBeijing 100081China

The reduction-degree of the sample increases and the utilization ratio of gas decreases when the reaction lasts longer time,which indicates that the reaction is faster at the beginning of reduction,while it becomes slower in subsequent *** higher the reaction temperature,the higher the utilization ratio of gas and the reduction-degree are,but the difference of utilization ratio among the different temperatures becomes smaller with *** utilization ratio of gas can reach about 8% and the reduction-degree is 80% for 20 min reduction at 850 ℃,indicating that the reduction reaction by CO is very fast at high *** higher the reaction temperature,the higher the apparent reaction rate constant is,but the difference of apparent reaction rate constant among the different temperatures becomes *** apparent activation energy is about 59.11 kJ/mol in the fluidized bed *** increase of reduction-degree with gas velocity shows quite good linearity,indicating that at high temperature even higher velocity of reducing gas can be used to improve the productivity of reactor when CO is used as reducing *** the increase of charge height,the metallization ratio and the reduction-degree decrease,but the utilization ratio of gas increases.

关键词： CO fluidized bed fine powder iron ore reduction-degree

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

Melting Characteristics of iron ore Fine During Sintering Process

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Journal of iron and Steel Research International 2011年第5期18卷 11-15页

作者： LI Hong-ge ZHANG Jian-liang PEI Yuan-dong ZHAO Zhi-xing MA Ze-jun School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Shougang Mining Company Qian′an 064404HebeiChina Shougang Research Institute of Technology Beijing 100043China

The whole melting curve of iron ore during sintering process was obtained,and the melting characteristics of iron ore were defined and explained. The whole melting process of mixture,mixed by iron ore and CaO reagent at basicity of 2.0 and 4.0,respectively,was observed using a SiC heating furnace with camcorder unit,and the melting curves of mixture that were relative height vs temperature curves were obtained. Besides,the melting characteristics of iron ore during sintering were introduced through defining some points in the melting curves,such as liquid forming temperature,inflexion temperature and flowing temperature,and the meaning of different shapes of the melting curves was clarified.

关键词： iron ore sintering melting characteristic melting curve

Quantitative Analysis of Fe Content in iron ore via External Calibration in Conjunction with Internal Standardization Method Coupled with LIBS

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Chemical Research in Chinese Universities 2015年第1期31卷 107-111页

作者： SHENG Liwen ZHANG Tianlong WANG Kang TANG Hongsheng LI Hua Institute of Analytical Science College of Chemistry & Materials Science Northwest University Xi 'an 710069 P. R. China College of Science Chang 'an University Xi 'an 710064 P. R. China

The external calibration in conjunction with internal standardization（ECIS） coupled with laser-induced breakdown spectroscopic（LIBS） technique was proposed to perform the quantitative analysis of Fe content in iron ore The plasma temperature and the electron number density were calculated to prove that the plasma was under local thermodynamic equilibrium（LTE） conditions and to ensure that the integral intensities of Fe I lines were reasonable. In addition, the result of the quantitative analysis shows a content of （20.26±0.59）% by mass of Fe in the iron ore. It was determined by four calibration curves, drawn for four emission lines of Fe I（373.48, 373.71,404.58 and 438.35 nm） normalized by Mn I line, base on the ECIS method which can eliminate the influence of matrix effect and improve the accuracy of quantitative analysis, compared with the standard addition method. Both the results of these two analytical methods were compared with that listed in the Standard Substance Certificate. The percentage content of Fe in the same sample of iron ore by the ECIS method was （20.17±0.08）% by mass, which shows a good performance to analyze the Fe content of iron ore in combination with LIBS.

关键词： Laser-induced breakdown spectroscopy(LIBS) External calibration in conjunction with internal standardization(ECIS) method Chemical analysis iron ore

Life Cycle Assessment of iron ore Sintering Process

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Journal of iron and Steel Research International 2015年第6期22卷 473-477页

作者： Zong-ping LI Xiao-hui FAN Gui-ming YANG Jin-chao WEI Ying SUN Min WANG School of Minerals Processing and Bioengineering Central South University Zhongye Changtian International Engineering Co. Ltd.

iron ore sintering is an energy＇intensive process associated with emission of pollutants in iron and steel in- dustry. In order to comprehensively evaluate the environmental impacts of sintering, a detailed life cycle assessment of a sintering plant was conducted. Life cycle inventory showed that, in the production of 1 t sinter ore, 241.53 kg CO2 , 22.68 kg CO, 0. 294 kg SO2 , 0.63 kg NO, , 1.18 /lg dioxin and 0.48 kg dust were discharged. Global war- ming potentials, acidification potentials, photochemical ozone creation potentials and human toxicity potentials were selected as four impact categories, and the evaluation index for the sintering plant was calculated as 3.45 × 10 ^-12. Fi nally, based on the environmental impact analysis, several measures of reducing environmental [oadings of the sinte- ring plant were provided, which included the utilization of denitrification equipment, recirculation of the hot waste gas and process improvement to reduce fuel consumption.

关键词： iron ore sintering plant life cycle assessment pollutant emission environmental loading

The Prospects of Uganda’s iron ore Deposits in Developing the iron and Steel Industry

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Journal of Minerals and Materials Characterization and Engineering 2020年第4期8卷 316-329页

作者： Muwanguzi J. B. Abraham Rukenzo Gift Sebukeera Hennery Guloba Asuman Ajidiru Rita Dumba Dexter Muvawala Joseph Science Technology and Innovations Department National Planning Authority Kampala Uganda Transport & Infrastructure Expertise Group Ezhz (Tieg) Stupava Slovak Republic

Uganda aspires to exploit its abundant iron ore resources to supply the required raw material for developing its iron and steel industry across all the phases of the value chain. The country imports USD 369 million worth of iron and steel products annually, 60% of which are raw materials for the steel processing plants. The National Planning Authority, the government planning agency, undertook a study to assess the possibility of using the iron ore deposits available in the country, as a source of supply for iron and steel production. In the study, available geological literature was collected from various sources and analysed in order to understand the mode of iron ore mineralization in Uganda, particularly, that in the South West. A field excursion to the deposits was conducted in order to ground truth the information obtained from literature research;carry out a detailed reconnaissance study so as to benchmark the likely scenarios required in the development of the iron and steel value chain;and establish the likely mining and processing requirements of the deposits. The reconnaissance survey confirmed the existence of hematite deposits that visually show characteristics of high-quality iron ore (55% - 68% Fe) suitable for iron production. From surficial investigations, the deposits are mainly comprised of thin beds of mineralisation. The deposits occur in the form of massive hematite, which is amenable to mining and direct feed to the ore processing plants, and specularite hematite (a metamorphic platy variety), which normally requires mineral processing for amenability to reduction processes. From the analysis, the country has sufficient deposits of a high grade that can support a steel industry, though more detailed quantifications and characterisations need to be prioritised by the government.

关键词： Mineralization iron ore iron Steel Geology NPA Uganda

Geochemical Signature and Metalogeny of BIFs and Associated iron ore of Zatua Hills, Haut-Uele Province (DR Congo)

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Journal of Geoscience and Environment Protection 2023年第10期11卷 201-217页

作者： Levesque Makuku Mbo Dominique Wetshondo Osomba Valentin Kanda Nkula Kelly Nzambe Keyila Albert Ongendangenda Tshiende Department of Geosciences Faculty of Science and Technology University of Kinshasa Kinshasa DR Congo Geological and Mining Research Center (CRGM) Kinshasa DR Congo Faculty of Oil Gas and Renewable Energies University of Kinshasa Kinshasa DR Congo

Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has remained a witness to a stable zone not affected by the ancient erosion process. BIFs are most abundant and are dated to the Neoarchaean and Late Kibalian, hosted in the Upper Congo Granites Massifs of the DR. Congo. Zatua Hills consist of dolerite, phyllade, clay-rich sediment, poor itabirite, enriched BIFs, friable hematite, hard hematite, and mineralized and unmineralized breccias. Field study and geochemistry analysis by XRF, XRD, and ICP-MS are executed in order to know the geochemistry signature and paragenesis of Zatua Hills and the probably process could lead the BIFs to iron ore. The geochemistry analysis by XRF, XRD, and ICP-MS shows that iron ore content has an iron rate between 57% and 69% with less deleterious elements such as Si, P, and Al. These deleterious elements are secondary and have silicium composition (probably quartz or chert, goethite, and Kaolinite), aluminum (probably gibbsite, variscite, cadwaladérite, goethite, and Kaolinite), phosphorous (probably variscite), and hydrated minerals, which are grown LOI in the samples. Hypogen and supergen processes are played in BIFs for iron ore conversion and, respectively, silica dissolution and leaching. Metamorphism was also impacted and marked by the Ti element (anatase) in samples, contributing to the crystallization of martite to hematite after magnetite oxidation.

关键词： BIFs Zatua Hills Geochemestry DRC iron ore