scholarly journals Recovery of Iron, Chromium, and Nickel from Pickling Sludge Using Smelting Reduction

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 936 ◽  
Author(s):  
Zhaohui Tang ◽  
Xueyong Ding ◽  
Xinlin Yan ◽  
Yue Dong ◽  
Chenghong Liu
Keyword(s):  
Reduction Process ◽  
Slag Basicity ◽  
Experimental Results ◽  
Iron Ores ◽  
Reduction Temperature ◽  
Smelting Reduction ◽  
Reduction Time ◽  
Temperature Reduction ◽  
Pickling Sludge ◽  
Iron Chromium

This paper reports the recoveries of iron, chromium, and nickel from pickling sludge using coal-based smelting reduction. The influences of slag basicity (CaO/SiO2, which is controlled by high phosphorus oolitic hematite iron ores), reduction temperature, reduction time, and the C/O mole ratio on the recoveries of Fe, Cr, and Ni are investigated systematically. The experimental results show that high recoveries of Fe (98.91%), Cr (98.46%), and Ni (99.44%) are produced from pickling sludge with optimized parameters for the smelting reduction process. The optimized parameters are a slag basicity of 1.5; a reduction temperature of 1550 °C, a reduction time of 90 min, and a C/O mole ratio of 2.0. These parameters can be used as technical support for the recycling of pickling sludge with pyrometallurgy.

Impact of slag composition activity on the behavior of phosphorus in the smelting reduction process of high-phosphorus iron ores

2017 ◽  
Vol 42 (38) ◽  
pp. 24487-24494 ◽  
Author(s):  
Yiqin Liu ◽  
Hao Zhang ◽  
Zengen Li ◽  
Aimin Zhang ◽  
Xiaohui Zhang ◽  
...  
Keyword(s):  
Slag Composition ◽  
Reduction Process ◽  
Iron Ores ◽  
Smelting Reduction ◽  
High Phosphorus ◽  
Phosphorus Iron

scholarly journals Effect of Different Additives on Reaction Characteristics of Fluorapatite During Coal-Based Reduction of Iron Ore

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 923 ◽  
Author(s):  
Yongsheng Sun ◽  
Wentao Zhou ◽  
Yuexin Han ◽  
Yanjun Li
Keyword(s):  
Iron Ore ◽  
Contact Point ◽  
Energy Dispersive Spectrometer ◽  
Structural Evolution ◽  
Reduction Process ◽  
Reduction Degree ◽  
Reduction Temperature ◽  
Exponential Factor ◽  
Reduction Time ◽  
Effect Mechanism

In the coal-based reduction of high phosphorus oolitic hematite, it is particularly important to study the mechanism of phosphorus regulation during the formation of iron metals for the efficient development and utilization of iron ore. In this study, the thermodynamics of the coal-based reduction process of fluorapatite in different mineral systems, effect mechanism of the reduction degree, kinetics, mineral composition, and morphology of structural evolution samples were systematically investigated using FactSage software, single factor analysis, the isothermal method, X-ray diffraction (XRD), scanning electron microscope (SEM), and an energy dispersive spectrometer (EDS). Thermodynamic analysis indicates that the effect of the SiO2–Fe2O3–C system on reducing the initial reduction temperature of fluorapatite was stronger than that of the Al2O3–Fe2O3–C system. The effect mechanism of the reduction degree demonstrates that increasing the dosage of silica, iron oxide, carbon, reduction time, and reduction temperature could promote the reduction reaction of fluorapatite under certain conditions. Dynamics analysis shows that the best kinetic mechanism functions of the SiO2–Fe2O3–C system and the Al2O3–Fe2O3–C system were A1/3 = 1/3(1 − α)[−ln(1 − α)]−2 and A1/2 = 1/2(1 − α)[−ln(1 − α)]−1, respectively. The activation energy and pre-exponential factor of the reduction kinetics equation in the system containing silica were significantly lower than that in the system containing alumina, which explained that the catalytic effect of silica on the reduction of calcium fluorophosphate was far greater than that of alumina. XRD and SEM/EDS analysis indicate that the solid–solid reaction of alumina, silica, iron, and fluorapatite occurred during the reduction process, while calcium aluminate, calcium silicate, and calcium oxide were formed at the contact point. Among them, iron could absorb P2 gas so that it played a greater role in promoting the reduction of fluorapatite. Increasing the reduction temperature and prolonging the reduction time were beneficial to the reduction of fluorapatite.

scholarly journals Kinetic Studies on Gas-Based Reduction of Vanadium Titano-Magnetite Pellet

2018 ◽  
Author(s):  
Junwei Chen ◽  
Liang Mi ◽  
Yang Jiao ◽  
Xidong Wang
Keyword(s):  
Early Stage ◽  
Reduction Process ◽  
Kinetic Studies ◽  
Product Layer ◽  
Diffusion Control ◽  
Reduction Degree ◽  
Reduction Temperature ◽  
Pellet Size ◽  
Reduction Time ◽  
Time Reduction

Vanadium titano-magnetite is a significant resource in China, and in this study, we characterize its isothermal reduction mechanisms in the mixture of H2, CO, and N2 where the variables considered here include reduction time, reduction temperature, gas composition, and pellet size. The kinetics of the reduction process are mainly studied, which follows a shrinking core model. The results indicate that the reduction degree of oxidized VTM pellets increases with the increase of reduction time, reduction temperature but decreases with the increase of pellet size. Moreover, we found that an increase of H2/(H2+CO) ratio induces an increase of the reduction degree. Then the transformation of main Ti-bearing mineral phases is discussed, and the most probable reaction mechanism is revealed. In the whole reduction process, the kinetic results confirm the existence of an early stage and a latter stage, which are controlled by interface chemical reaction and diffusion, respectively. Furthermore, the results show that the diffusion-control step can be observably shortened with the decrease of pellet size because a thinner product layer is formed during the reduction process. Our study thus provides a valuable technical basis on the VTM industrial application.

scholarly journals Preparing Sc-Bearing Master Alloy Using Aluminum–Magnesium Thermoreduction Method

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 960 ◽  
Author(s):  
Junhui Xiao ◽  
Wei Ding ◽  
Yang Peng ◽  
Tao Chen ◽  
Kai Zou
Keyword(s):  
Molten Salt ◽  
Master Alloy ◽  
Experimental Results ◽  
Reduction Temperature ◽  
Reduction Time ◽  
Alloy Ingot ◽  
Master Alloy Ingot

In this study, preparation of Al–Mg–Sc master alloy tests were carried out by Al–Mg thermoreduction method. Stirring by blowing argon and pressing with molten salt jar were adopted to reduce scandium segregation and upgrading scandium recovery of scandium-bearing master alloy. The results show that the Al–Mg–Sc master alloy ingot contained 2.90% Sc, 5.73% Mg, 0.0058% Cu, 0.29%, 0.029% Ti, 0.13% Fe, 0.075% Zn, 0.025% Na, and 96.72% recovered scandium obtained under the comprehensive conditions used: m(Al): m(Mg): m(ScCl3) = 10:1:1.5, stirring speed of eight rpm, reduction temperature of 1223 K, reduction time of 40 min. The experimental results are in agreement with the thermodynamic predictions, and Al–Mg–Sc master alloy indicator was ideal.

scholarly journals Influence of MgO on Low Temperature Reduction and Mineralogical Changes of Sinter in Simulated COREX Shaft Furnace Reducing Conditions

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 272 ◽  
Author(s):  
Deqing Zhu ◽  
Jianlei Chou ◽  
Benjing Shi ◽  
Jian Pan
Keyword(s):  
Low Temperature ◽  
Shaft Furnace ◽  
Reduction Rate ◽  
Reduction Process ◽  
Smelting Reduction ◽  
Temperature Reduction ◽  
Corex Shaft Furnace ◽  
Reducing Conditions ◽  
Before And After ◽  
Low Temperature Reduction

COREX (Coal-Reduction-Extreme) smelting reduction process provides a sustainable developing way for ironmaking industry, but the sources of iron ore materials restrict its development in China. Meanwhile, the application of sinter, which is marked by low manufacture cost and overcapacity in China, to COREX furnace faced proportion limitation due to its worse low temperature reduction degradation performance. This work explored the influence of MgO content on the low-temperature (550 °C) reduction of sinter in reducing conditions simulating COREX shaft furnace. The mineralogical change of sinter containing different content of MgO before and after reduction was analyzed by X-ray diffraction (XRD), optical microscopy, and scanning electron microscopy for revealing the action mechanism of MgO on the low-temperature-reduction of sinter. The results show that increasing MgO (1.36–3.10%) improved the low temperature reduction degradation performance of sinter, and decreased its reduction degree and reduction rate at low temperature. More MgO the sinter contained, less Fe2O3 and SFCA was observed in sinter. Meantime, less Fe2O3 was reduced and the generation of innerstress was restrained during reduction process. The improved RDI (reduction degradation index) in COREX process of sinter by increasing MgO content is a comprehensive result of lowering strength and inhibiting probable reduction of sinter.

scholarly journals Kinetic Studies on Gas-Based Reduction of Vanadium Titano-Magnetite Pellet

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 95 ◽  
Author(s):  
Junwei Chen ◽  
Weibin Chen ◽  
Liang Mi ◽  
Yang Jiao ◽  
Xidong Wang
Keyword(s):  
Reduction Process ◽  
Kinetic Studies ◽  
Industrial Applications ◽  
Product Layer ◽  
Diffusion Control ◽  
Reduction Degree ◽  
Reduction Temperature ◽  
Pellet Size ◽  
Reduction Time ◽  
Shrinking Core

Vanadium titano-magnetite (VTM) is a significant resource in China—analysis shows that China possesses approximately 10 billion tons of VTM. In this study, we characterize VTM’s isothermal reduction mechanisms in the mixture of H2, CO, and N2 where the variables considered include reduction time, reduction temperature, gas composition, and pellet size. The kinetics of the reduction process were studied following a shrinking core model. The results indicate that the reduction degree of oxidized VTM pellets increases with increases of reduction time and reduction temperature but decreases with increasing pellet size. Moreover, we found that an increase of H2/(H2 + CO) ratio induced an increase of the reduction degree. We discuss the transformation of main Ti-bearing mineral phases, and we consider the most probable reaction mechanism. For the entire reduction process, the kinetic results confirm the existence of an early and later stages that are controlled by interface chemical reaction and diffusion, respectively. Furthermore, the results show that the diffusion-control step can be observably shortened via decreased pellet size because a thinner product layer is formed during the reduction process. Our study thus provides a valuable technical basis for industrial applications of VTM.

scholarly journals Influence of Parameters on the Pre-Reduction Process of Vanadium-Titanium Magnetite Carbon-Containing Composite Pellets in Rotary Kiln

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 45
Author(s):  
Bo Wang ◽  
Xueyong Ding ◽  
Tianhua Ju ◽  
Xiaofei Zhang ◽  
Gongjin Cheng
Keyword(s):  
Rotary Kiln ◽  
Reduction Process ◽  
Holding Time ◽  
Reduction Temperature ◽  
Smelting Reduction ◽  
Total Oxygen ◽  
Metallization Rate ◽  
Composite Pellets ◽  
Melting Pool ◽  
Titanium Magnetite

A novel smelting reduction process called pre-reduction in rotary kiln and total oxygen melting pool is a promising route to reduce environmental pollution from the ironmaking industry. In this paper, the process parameters and appropriate efficiency of reduction in the pre-reduction process of the rotary kiln were investigated via the detection of the metallization rate, phase composition, and internal morphology of the product combining with the analysis of the off-gas. The results indicated that the parameters of reduction temperature, reduction holding time, and coal ratio have a remarkable influence on the metallization rate. The reduction temperature has the most significant effect, followed by the reduction time and the coal ratio. Furthermore, under the condition of reduction temperature 1000 °C, holding time 30 min, coal ratio = 1, a product with a metallization rate of more than 70% can be obtained, which meets the requirements of the rotary kiln process, and its CO2/CO value of the pre-reduction endpoint is appropriate. Continue to increase the temperature, holding time, and coal ratio can raise the metallization rate of the pellets, but only a little improvement and may cause reoxidation of the product.

scholarly journals Impact of Iron on the Fe–Co–Ni Ternary Nanocomposites Structural and Magnetic Features Obtained via Chemical Precipitation Followed by Reduction Process for Various Magnetically Coupled Devices Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 341
Author(s):  
Tien Hiep Nguyen ◽  
Gopalu Karunakaran ◽  
Yu.V. Konyukhov ◽  
Nguyen Van Minh ◽  
D.Yu. Karpenkov ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Reduction Process ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Magnetic Characteristics ◽  
Reduction Temperature ◽  
Fe Content ◽  
Magnetic Features ◽  
Co Precipitation

This paper presents the synthesis of Fe–Co–Ni nanocomposites by chemical precipitation, followed by a reduction process. It was found that the influence of the chemical composition and reduction temperature greatly alters the phase formation, its structures, particle size distribution, and magnetic properties of Fe–Co–Ni nanocomposites. The initial hydroxides of Fe–Co–Ni combinations were prepared by the co-precipitation method from nitrate precursors and precipitated using alkali. The reduction process was carried out by hydrogen in the temperature range of 300–500 °C under isothermal conditions. The nanocomposites had metallic and intermetallic phases with different lattice parameter values due to the increase in Fe content. In this paper, we showed that the values of the magnetic parameters of nanocomposites can be controlled in the ranges of MS = 7.6–192.5 Am2/kg, Mr = 0.4–39.7 Am2/kg, Mr/Ms = 0.02–0.32, and HcM = 4.72–60.68 kA/m by regulating the composition and reduction temperature of the Fe–Co–Ni composites. Due to the reduction process, drastic variations in the magnetic features result from the intermetallic and metallic face formation. The variation in magnetic characteristics is guided by the reduction degree, particle size growth, and crystallinity enhancement. Moreover, the reduction of the surface spins fraction of the nanocomposites under their growth induced an increase in the saturation magnetization. This is the first report where the influence of Fe content on the Fe–Co–Ni ternary system phase content and magnetic properties was evaluated. The Fe–Co–Ni ternary nanocomposites obtained by co-precipitation, followed by the hydrogen reduction led to the formation of better magnetic materials for various magnetically coupled device applications.

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.

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