scholarly journals Effect of Carbon Addition on Direct Reduction Behavior of Low Quality Magnetite Ore by Reducing Gas Atmosphere

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1404
Author(s):  
Seongrim Song ◽  
Youngjo Kang
Keyword(s):  
Direct Reduction ◽  
Reduction Process ◽  
Hydrocarbon Fuel ◽  
Carbon Composite ◽  
Direct Reduced Iron ◽  
Carbon Efficiency ◽  
Reducing Gas ◽  
Initial Reduction ◽  
Coal Particles ◽  
Composite Pellets

Recently, direct reduced iron (DRI) has been highlighted as a promising iron source for electric arc furnace (EAF)-based steelmaking. The two typical production methods for DRI are gas-based reduction and reduction using carbon composite pellets. While the gas-based reduction is strongly dependent on the reliable supply of hydrocarbon fuel, reduction using ore-coal composite pellets has relatively low productivity due to solid–solid reactions. To overcome the limitations of the above two processes, and to achieve a more efficient direct reduction process of iron ore, the possibility of combining these two methods was investigated. The experiments focused on performing an initial direct reduction using ore-coal composite pellets followed by a second stage gas reduction. It was assumed that the initial reduction of the carbon composite pellets would enhance the efficiency of the subsequent reduction by gas and the total reduction efficiency. The porosity, as well as the carbon efficiency for direct reduction, were measured to determine the optimal conditions for the initial reduction, such as the size ratio of ore and coal particles. Thereafter, further reduction by the reducing gas was carried out to verify the effect of the preliminary reduction. The reduction kinetics of the reducing gas was also discussed.

Numerical analysis of the carbon containing pellets direct reduction process

2021 ◽  
Vol 118 (2) ◽  
pp. 209
Author(s):  
Nan Li ◽  
Feng Wang ◽  
Wei Zhang
Keyword(s):  
Direct Reduction ◽  
Reduction Process ◽  
Operating Conditions ◽  
Utilization Efficiency ◽  
Heat Absorption ◽  
Furnace Temperature ◽  
Chemical Reaction Kinetics ◽  
Direct Reduction Process ◽  
Pellet Surface ◽  
Composite Pellets

In view of the carbon-containing composite pellets direct reduction process in rotary hearth furnace, a mathematical model coupling heterogeneous chemical reaction kinetics, heat and mass transfer of this process was established. The effects of furnace temperature (from 1273.15 K to 1673.15 K) and pellet radius (from 6 mm to 16 mm) on the direct reduction of carbon-containing composite pellets were studied by adopting computational fluid dynamics software. The pellet temperature and composition changes under different operating conditions were analyzed. CO and CO2 fluxes, heat fluxes on the pellet surface were especially studied. Total heat absorption by the pellet, CO and CO2 overflow from the pellet surface together with pellet degree of metallization (DOM) and zinc removal rate (ZRR) were calculated. Results show that with the increasing of furnace temperature or the decreasing of the pellet radius, the temperature difference between pellet surface and its center and the final DOM, ZRR increased. The larger the pellet radius, the smaller the heat absorption, also the smaller CO and CO2 overflow. But heat absorption and CO overflow per unit volume are higher. There is an optimal pellet radius with high CO utilization efficiency. Pellet porosity decreases at first and then increases with reducing time. It is also found that effective thermal conductivity is a major factor limiting the pellets temperature increasing. The reduction sequence of the pellets is Fe2O3→Fe3O4→FeO→Fe.

Direct reduction of copper slag-carbon composite pellets by coal and biochar

2019 ◽  
Vol 41 (17) ◽  
pp. 2240-2252 ◽  
Author(s):  
Zongliang Zuo ◽  
Qingbo Yu ◽  
Huaqing Xie ◽  
Fan Yang ◽  
Zhicheng Han ◽  
...  
Keyword(s):  
Direct Reduction ◽  
Copper Slag ◽  
Carbon Composite ◽  
Composite Pellets

The Effects of Reduction Parameter to Composite Pelet of Iron Ore and Coal Using Single Conveyor Belt Hearth Furnace

2016 ◽  
Vol 842 ◽  
pp. 115-119
Author(s):  
Johny Wahyuadi Soedarsono ◽  
Andi Rustandi ◽  
Yudha Pratesa ◽  
Rianti Dewi Sulamet-Ariobimo ◽  
Bagus Hadi Prabowo ◽  
...  
Keyword(s):  
Iron Ore ◽  
Direct Reduction ◽  
Reduction Process ◽  
Conveyor Belt ◽  
Separation Process ◽  
Iron Ores ◽  
Hearth Furnace ◽  
Composite Pellet ◽  
Direct Reduction Iron ◽  
Composite Pellets

Iron ores should be separated from oxygen and impurities which are coming along during the mining process. The separation process is known as reduction. There are two types of reduction process, and the most common is direct reduction process (DRP). There are several parameters in DRP which will determine the quantities of the product known as direct reduction iron (DRI). This worked discussed the effect of reduction temperature and pellet heap to the quantities of DRI using single conveyer belt Hearth furnace. The worked was done in laboratory scale using composite pellets with 14 mm in diameter. The ratio of iron ore to coal in the composite pellet is 1 to 1. The reduction process temperatures are 500oC, 700oC and 900oC. The reduction time is 25 minutes. While the pellets heap are also varied to 1, 3, 5, 7, 8 and 9 layers. The results show that DRI was formed in 700OC and the quantities of DRI are in line with the reduction temperatures and layers of composite pellets heap.

Research on the Recovery of Secondary Iron-Bearing Dust in Direct Reduction of Carbon Composite Pellets

2012 ◽  
Vol 524-527 ◽  
pp. 2031-2036
Author(s):  
Yi Shan Li ◽  
Zheng Liang Xue ◽  
En Tang ◽  
Qiang Liu ◽  
Wei Xiang Wang ◽  
...  
Keyword(s):  
Raw Materials ◽  
Direct Reduction ◽  
Carbon Composite ◽  
Molten Iron ◽  
Molar Ratio ◽  
Good Surface ◽  
Composite Pellets ◽  
Iron Phase ◽  
Converter Sludge ◽  
Iron Bearing

In order to recover secondary iron-bearing dust, with converter sludge, mill scale, gravitational ash, casthouse ash as raw materials, high basicity carbon composite pellets are prepared to make iron nuggets through self-reduction at high temperature. The study demonstrates that: The effectively separation of iron and slag, naturally pulverization of the slag phase, and good surface quality of bigger, glosser and brighter iron nuggets can be obtained with reduction temperature 1400 °C,C/O molar ratio 1.1,as well as basicity above 1.8 in this process; The iron phase is not generated well and proportion of small size iron nuggets increases when C/O molar ratio is increased; With C/O molar ratio increases or temperature rises, CO generated increases in direct reduction, which strengthen the reducibility atmosphere in the pellets, beneficial to the processing of desulfuration and dephosphorization; Rising temperature accelerates the generation of molten iron, so that, the fixed carbon contacts with the molten iron longer, which increasing the carbon in iron nuggets. More carbon is provided for the carburizing reaction for the sake of increasing C/O molar ratio, as a result of making more carbon in iron nuggets.

scholarly journals Carbothermic Reduction of Ore-Coal Composite Pellets in a Tall Pellets Bed

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 550 ◽  
Author(s):  
Xin Jiang ◽  
Guangen Ding ◽  
He Guo ◽  
Qiangjian Gao ◽  
Fengman Shen
Keyword(s):  
Carbothermic Reduction ◽  
Molten Slag ◽  
Direct Reduction ◽  
High Quality ◽  
Commercial Development ◽  
Experimental Conditions ◽  
Furnace Process ◽  
Direct Reduced Iron ◽  
Composite Pellets ◽  
Actual Operation

Recently, increasing attention has been paid to alternative ironmaking processes due to the desire for sustainable development. Aiming to develop a new direct reduction technology, the paired straight hearth (PSH) furnace process, the carbothermic reduction of ore-coal composite pellets in a tall pellets bed was investigated at the lab-scale in the present work. The experimental results show that, under the present experimental conditions, when the height of the pellets bed is 80 mm (16–18 mm each layer, and 5 layers), the optimal amount of carbon to add is C/O = 0.95. Addition of either more or less carbon does not benefit the production of high quality direct reduced iron (DRI). The longer reduction time (60 min) may result in more molten slag in the top layer of DRI, which does not benefit the actual operation. At 50 min, the metallization degree could be up to 85.24%. When the experiment was performed using 5 layers of pellets (about 80 mm in height) and at 50 min duration, the productivity of metallic iron could reach 55.41 kg-MFe/m2·h (or 75.26 kg-DRI/m2·h). Therefore, compared with a traditional shallow bed (one or two layers), the metallization degree and productivity of DRI can be effectively increased in a tall pellets bed. It should be pointed out that the pellets bed and the temperature should be increased simultaneously. The present investigation may give some guidance for the commercial development of the PSH process in the future.

Research on Direct Reduction Dynamic Model of Carbon-Bearing Pellet Containing Zinc

2011 ◽  
Vol 214 ◽  
pp. 369-373
Author(s):  
Jing Song Wang ◽  
Xiu Wei An ◽  
Wan Hua Yu ◽  
Xue Feng She ◽  
Yin Gui Ding ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Mathematical Model ◽  
Direct Reduction ◽  
Reduction Process ◽  
Reduction Temperature ◽  
Coupled Heat Transfer ◽  
Reducing Gas ◽  
Metallization Rate ◽  
Process Factors

Base on reduction experimental data, considering the reduction process factors like carbon content, reductive removal of ZnO, changing size of pellet, and partial pressure of reducing gas, also coupled heat transfer, mass transfer and chemical reactions, a direct reduction mathematical model on carbon-bearing pellet containing zinc has been established. The reliability of the model was testified by programming and experiments. Experiments showed that, under the reduction conditions that carbon and oxygen mole ratio at 1.0 and reduction temperature 1603K, metallization rate 87% and dezincification rate 99% were observed after 15 minutes of heating.

Metallographic Estimation of the Number of Forming Metallic Particles Obtained during Direct and Indirect Reduction of Metals from Complex Oxides

2019 ◽  
Vol 946 ◽  
pp. 523-527
Author(s):  
Arman S. Bilgenov ◽  
P.A. Gamov ◽  
V.E. Roshchin
Keyword(s):  
Metal Forming ◽  
Solid Phase ◽  
Quantitative Estimation ◽  
Direct Reduction ◽  
Reduction Process ◽  
Complex Oxide ◽  
Experimental Results ◽  
Solid Carbon ◽  
Indirect Reduction ◽  
Co Gas

The direct reduction of metals from a complex oxide with low iron content by solid carbon and indirect reduction by CO gas were studied in a vertical laboratory resistance furnace at 1300 °C for an hour reduction time. The experimental results were described from the point of view of the electrochemical nature of the metal reduction process, that involves the interaction of ions and electrons in the oxide lattice. The technique was developed by using the two different software programs for the quantitative estimation of the areas, average size and number of the metal forming in a complex oxide with extensive fields of vision. The obtained results of the quantitative characteristics of the metal forming during solid-phase carbo-thermal reduction were presented. The processes of reduction by solid carbon and CO gas based on the areas occupied by metal particles were quantitatively compared. The experimental results and the prospects for further experimental work were assessed and outlined.

Separation of aluminium and preparation of powdered DRI from lateritic iron ore based on direct reduction process

2016 ◽  
Vol 55 (3) ◽  
pp. 345-355 ◽  
Author(s):  
T. Jiang ◽  
L. Yang ◽  
G. Li ◽  
J. Luo ◽  
J. Zeng ◽  
...  
Keyword(s):  
Iron Ore ◽  
Direct Reduction ◽  
Reduction Process ◽  
Direct Reduction Process
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