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.

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.

scholarly journals A Clean Process to Prepare High-Quality Acid-Soluble Titanium Slag from Titanium Middling Ore

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 460 ◽  
Author(s):  
Jiqing Han ◽  
Jing Zhang ◽  
Wei Feng ◽  
Xiao Chen ◽  
Li Zhang ◽  
...  
Keyword(s):  
Direct Reduction ◽  
Dilute Acid ◽  
X Ray Diffraction ◽  
High Quality ◽  
Experimental Conditions ◽  
Titanium Slag ◽  
Acid Washing ◽  
Washing Process ◽  
Alkali Leaching ◽  
Increasing Temperature

A direct reduction-magnetic separation-alkali leaching-dilute acid washing method was proposed to prepare high-quality acid-soluble titanium slag (HQASTS) from titanium middling ore. The relevant potential pH diagrams were built, and the analysis results showed that the pH values for alkali leaching and dilute acid washing should be higher than 13.50 and lower than 1.00, respectively. Increasing temperature was beneficial to alkali leaching but not to dilute acid washing. The effects of operating parameters on the TiO2 content and impurity oxides extraction ratios of titanium slag were investigated, and the optimal experimental conditions were obtained. The HQASTS was obtained with TiO2 and Fe2O3 content of 75.37 wt % and 0.96 wt %, respectively, under the above conditions. Furthermore, the leaching mechanism was studied by chemical analysis and X-ray diffraction (XRD) technology, and it was found that the alkali leaching-dilute acid washing process presented in this work could avoid the encapsulation of the unreacted anorthite by the calcium aluminum spinel generated in alkali leaching.

Enterprise Education Research In The Context Of Moral Training In Chinese Colleges

2014 ◽  
Vol 1 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Rufei Zhang
Keyword(s):  
College Students ◽  
Education Research ◽  
Status Quo ◽  
Teaching Staff ◽  
High Quality ◽  
The Poor ◽  
Moral Training ◽  
Enterprise Education ◽  
Actual Operation ◽  
Practical Effect

AbstractIt has become a necessary requirement of the time for colleges to carry out enterprise education to produce high-quality personnel with entrepreneur spirit and ability. It is discussed at the beginning of this article that the purpose and status quo of the enterprise education for college students in China and then the reasons for the poor condition in enterprise education are explored. It is found out that colleges do not provide an effective systematic platform for enterprise education; necessary personnel are not provided for such purpose in the teaching staff in Chinese colleges; in actual operation practical effect is not achieved in the moral training in colleges. Therefore, new concept in moral training must be introduced and first-rate teaching staff must be provided for the effective enterprise education. Special courses must also be systematically compiled for the purpose.

Characteristics of Sea-Water Ice Slurry for Cooling of Fish

2013 ◽  
Vol 388 ◽  
pp. 123-127 ◽  
Author(s):  
Agus Sunjarianto Pamitran ◽  
Helmi Dadang Ardiansyah ◽  
Mach Novviali
Keyword(s):  
Solid Surface ◽  
Chemical Equilibrium ◽  
Sea Water ◽  
Freezing Point ◽  
Good Time ◽  
Ice Slurry ◽  
High Quality ◽  
Experimental Conditions ◽  
Water Ice ◽  
Cooling Method

A more effective of cooling method is necessary for fish storage to get high quality and long freshness of fish. Ice block is not sufficient for fish storage because of its hard-solid surface that can damage the fish. Moreover for some remote area it is difficult to find ice block in good time with reasonable/low price. One solution for this problem is the using of sea-water ice slurry for fish cooling. Ice slurry is formed when the sea-water temperature goes down to its freezing point, when the early nucleation is formed. Crystal ice can be formed when chemical equilibrium is occurred. The purpose of this present study is to observe the characteristics of ice slurry generation using scraper blade evaporator and orbital rod evaporator. The experiment is done under some experimental conditions.

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

Shaft Furnace Direct Reduction Technology - Midrex and Energiron

2013 ◽  
Vol 805-806 ◽  
pp. 654-659 ◽  
Author(s):  
Xin Jiang ◽  
Lin Wang ◽  
Feng Man Shen
Keyword(s):  
Natural Gas ◽  
Heat Recovery ◽  
Shaft Furnace ◽  
Direct Reduction ◽  
Waste Recycling ◽  
Iron And Steel Industry ◽  
Iron And Steel ◽  
Direct Reduced Iron ◽  
Worldwide Production ◽  
Reforming Gas

Coke constitutes the major portion of ironmaking cost and its production causes the severe environmental concerns. So lower energy consumption, lower CO2 emission and waste recycling are driving the iron and steel industry to develop alternative, or coke-free, ironmaking process. Midrex and HYL Energiron are the leading technologies in shaft furnace direct reduction, and they account for about 76% of worldwide production. They are the most competitive ways to obtain high quality direct reduced iron (DRI) for steelmaking. Therefore, in the present paper, some detailed information about these two processes are given. Much attention has been paid on process scheme, the feedstock, DRI product, heat recovery, reforming gas, hot discharge and transportation, and by-product emission. Its very important for direct reduction development in both natural gas-rich counties and natural gas-poor counties.

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