scholarly journals Influence of a Prior Oxidation on the Reduction Behavior of Magnetite Iron Ore Ultra-Fines Using Hydrogen

2021 ◽  
Author(s):  
Thomas Wolfinger ◽  
Daniel Spreitzer ◽  
Heng Zheng ◽  
Johannes Schenk
Keyword(s):  
Iron Ore ◽  
Direct Reduction ◽  
Reduction Behavior ◽  
Thermogravimetric Analyzer ◽  
Initial Stage ◽  
Degree Of Oxidation ◽  
Apparent Activation Energies ◽  
High Degree ◽  
Positive Effect ◽  
Prior Oxidation

AbstractThe reduction behavior of raw and prior-oxidized magnetite iron ore ultra-fines with hydrogen was investigated. Reduction tests were conducted with a thermogravimetric analyzer in a temperature range from 873 K to 1098 K at 1.1 bar absolute, using hydrogen as reducing gas. The experimental results show that a prior oxidation of the magnetite has a positive effect on the reduction behavior because of changing morphology. The apparent activation energies show a turnaround to negative values, depending on the prior oxidation and degree of reduction. A multi-step kinetic analysis based on the model developed by Johnson–Mehl–Avrami was used to reveal the limiting mechanism during reduction. At 873 K and 948 K, the reduction at the initial stage is controlled by nucleation and chemical reaction and in the final stage by nucleation only, for both raw and pre-oxidized magnetites. At higher temperatures, 1023 K and 1098 K, the reduction of raw magnetite is mainly controlled by diffusion. This changes for pre-oxidized magnetite to a mixed controlled mechanism at the initial stage. Processing magnetite iron ore ultra-fines with a hydrogen-based direct reduction technology, lower reduction temperatures and a prior oxidation are recommended, whereby a high degree of oxidation is not necessary.

Effects of reductant type on coal-based direct reduction of iron ore tailings

2018 ◽  
Vol 42 (3) ◽  
pp. 453-466
Author(s):  
Wei WANG ◽  
Pengfei YE ◽  
Xiaoli ZHOU ◽  
C WANG ◽  
Zekun HUO ◽  
...  
Keyword(s):  
Iron Ore ◽  
Direct Reduction ◽  
Iron Ore Tailings ◽  
Reduction Of Iron ◽  
Direct Reduction Of Iron

scholarly journals Rural Financial Development Impacts on Agricultural Technology Innovation: Evidence from China

2021 ◽  
Vol 18 (3) ◽  
pp. 1110
Author(s):  
Yuyu Liu ◽  
Duan Ji ◽  
Lin Zhang ◽  
Jingjing An ◽  
Wenyan Sun
Keyword(s):  
Economic Development ◽  
Financial Development ◽  
Agricultural Development ◽  
Technology Innovation ◽  
Agricultural Technology ◽  
Rural Finance ◽  
Rural Economic Development ◽  
High Degree ◽  
The Impact ◽  
Positive Effect

Agricultural technology innovation is key for improving productivity, sustainability, and resilience in food production and agriculture to contribute to public health. Using panel data of 31 provinces in China from 2003 to 2015, this study examines the impact of rural financial development on agricultural technology innovation from the perspective of rural financial scale and rural finance efficiency. Furthermore, it examines how the effects of rural financial development vary in regions with different levels of marketization and economic development. The empirical results show that the development of rural finance has a significant and positive effect on the level of agricultural technology innovation. Rural finance efficiency has a significantly positive effect on innovation in regions with a low degree of marketization, while the rural financial scale has a significantly positive effect on technological innovation in regions with a high degree of marketization. Further analysis showed that improving the level of agricultural technology innovation is conducive to rural economic development. This study provides new insights into the effects of rural financial development on sustainable agricultural development from the perspective of agricultural technology innovation.

scholarly journals Effect of Prior Oxidation on the Reduction Behavior of Magnetite-Based Iron Ore During Hydrogen-Induced Fluidized Bed Reduction

2021 ◽  
Author(s):  
Heng Zheng ◽  
Daniel Spreitzer ◽  
Thomas Wolfinger ◽  
Johannes Schenk ◽  
Runsheng Xu
Keyword(s):  
Fluidized Bed ◽  
Partial Oxidation ◽  
Iron Ore ◽  
Reduction Rate ◽  
Deep Oxidation ◽  
Initial Reaction ◽  
Oxidation Treatment ◽  
Rate Limiting Step ◽  
Rate Limiting ◽  
Prior Oxidation

AbstractMagnetite-based iron ore usually shows a high sticking tendency and a poor reducibility in the fluidized bed because of its dense structure. To enhance the fluidization and reduction behaviors of magnetite-based iron ore during hydrogen-induced fluidized bed reduction, the effect of a prior oxidation treatment is investigated. The results show that the untreated magnetite-based iron ore cannot be fluidized successfully in the tested temperature range between 600 °C and 800 °C. At 600 °C reduction temperature, the de-fluidization can be avoided by a prior oxidation treatment. At higher reduction temperatures, the fluidization behavior can be further improved by an addition of 0.5 wt pct MgO. Magnesiowüstite (FexMg1−xO) is formed, which decreases the contact chance of the sticky surface between particles. Regarding to the reduction rate, a prior partial oxidation is more beneficial compared to deep oxidation. The kinetic analysis shows that MgO could promote the initial reaction. The reaction rate limiting step is no longer diffusion but chemical reaction for prior partly oxidized samples. A prior partial oxidation combined with an addition of MgO is considered to be a promising pretreatment method for a successful processing of magnetite-based iron ore.

Stimulation of β-(l → 6)-glucanase production by oxidized pustulan

1972 ◽  
Vol 18 (10) ◽  
pp. 1543-1550 ◽  
Author(s):  
Robert G. Brown
Keyword(s):  
Enzyme Activity ◽  
Isoelectric Focusing ◽  
Gel Filtration ◽  
Tween 80 ◽  
Sole Source ◽  
Cellulase Production ◽  
Low Degree ◽  
Degree Of Oxidation ◽  
High Degree ◽  
Stimulation Of

A strain of Penicillium lilacinum, isolated from soil, produced pustulanase, β-(1 → 3)-glucanase, (EC. 3.2.1.6) and cellulase (EC.3.2.1.4) when cultivated on a medium containing pustulan as the sole source of carbon. If pustulan was replaced by ketopustulan, the production of pustulanase was stimulated about 10-fold although the amount of stimulation was dependent on the degree of oxidation of pustulan. β-(1 → 3)-Glucanase production was stimulated slightly by ketopustulan; however, the degree of oxidation did not affect significantly the yield of this enzyme. Cellulase production was either unaffected by the oxidized polymer, or at higher degrees of oxidation, decreased. Tween 80 stimulated the production of the three enzymes in media containing ketopustulan with a low degree of oxidation but was inhibitory to pustulanase and cellulase production in media containing ketopustulan with a high degree of oxidation. A combination of gel filtration and isoelectric focusing revealed that each enzyme activity was attributable to at least two proteins.

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

About Determing the Microhardness of Composite Coatings

2021 ◽  
Vol 1037 ◽  
pp. 486-493
Author(s):  
Sergey Y. Zhachkin ◽  
Anatoly I. Zavrazhnov ◽  
Nikita A. Penkov ◽  
George V. Kudryavtsev ◽  
Paul V. Tsisarenko
Keyword(s):  
Composite Coating ◽  
Mechanical Treatment ◽  
Composite Coatings ◽  
Operational Parameters ◽  
Deposition Parameters ◽  
Cylinder Liners ◽  
High Degree ◽  
Applied Coating ◽  
Positive Effect ◽  
Selection Of

One of the fundamental tasks in restoring the operability of cylinder liners is the application of a composite coating with a predetermined microhardness value. The authors have developed a technology for applying composite coatings based on iron on cylindrical surfaces, which makes it possible to vary the physical, mechanical and operational parameters of the formed iron-containing coating due to the planned selection of the deposition parameters. This eliminates the need for mechanical treatment of the applied coating, which is the reason for the high degree of rejection parts that undergo the iron-on operation. Contact interaction of the working tool with the formed layer of the composite coating has a positive effect on the value of its roughness.

CARNIVAL POLITICAL TECHNOLOGIES: MASKS OF LOCAL AUTHORITIES IN MODERN RUSSIA

2021 ◽  
Vol 16 (3) ◽  
pp. 53-68
Author(s):  
A.V. SKIPERSKIKH ◽  
Keyword(s):  
Political Process ◽  
Political Class ◽  
Current State ◽  
Cultural Specificity ◽  
The Russian Federation ◽  
The Government ◽  
Social Organism ◽  
High Degree ◽  
Game Forms ◽  
Positive Effect

The purpose of the research is to present how the carnival element in the regional policy is associated with the legitimating of power. Also made of the current state of the regional political process in some constituent entities of the Russian Federation, characterized by a high degree of carnivalization. As a result, the importance of the practices of the regional elite, resorting to game forms of their own positioning. The legitimacy of the regional power to depend on festive discourse. A routine political process in the constituent entities of the Russia does not evoke public emotions that have a positive effect on the legitimation of power. The demand for the politics of spectacle is also present in municipal political practices in a very dangerous epoch of COVID-19. A social organism that needs emotions, as well as control, does not experience serious transformations. In society penchant for spectacle, as well as the political class in the production of carnival events, there are deep historical roots, as well as the cultural specificity of a particular region. The points out that in the regional political process one can increasingly see accents on festivals. So, the government solves two important problems: the first one is a public request for a show, it is resolved in conditions of a rather unpleasant and unpromising accumulation of negative for the authorities due to the deterioration of the socio-economic situation in general, the second one is the production of the play solves the issues of legitimation regional and municipal authorities.

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