scholarly journals Reduction and Nitridation of Iron/Vanadium Oxides by Ammonia Gas: Mechanism and Preparation of FeV45N Alloy

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 356
Author(s):  
Yongjie Liu ◽  
Yue Wang ◽  
Zhixiong You ◽  
Xuewei Lv
Keyword(s):  
Morphological Analysis ◽  
Raw Materials ◽  
Direct Reduction ◽  
Reduction Process ◽  
Nitrogen Sources ◽  
X Ray Diffraction ◽  
Ammonia Gas ◽  
Metallic Oxides ◽  
Nitridation Process ◽  
Impurity Elements

The steel micro-alloyed with ferrovanadium nitride has extremely superior properties that make it widely utilized in structural components, construction and aircraft. The conventional methods for synthesizing ferrovanadium nitride include nitridation of pure ferrovanadium alloy or carbothermal nitridation of metallic oxides, using nitrogen or ammonia gas as nitrogen sources. In this study, ferrovanadium nitride (FeV45N) was prepared by direct reduction and nitridation of the corresponding metal oxides with ammonia as the reductant and nitrogen source. This method avoids the introduction of other impurity elements, except the negligible trace elements accompanied with the raw materials. The thermodynamics of the reduction and nitridation process were initially analyzed. During the subsequent ammonia reduction process, the FeV45N powders were successfully obtained at 1273 K for 6 h. The obtained powders were pressed into cylindrical briquettes by hot pressing (HP) at 1473 K for 1 h in vacuum. In the investigation, the X-ray diffraction and morphological analysis of the products was also carried out, and the reaction mechanisms were discussed in detail. The nitrogen content of the final product can reach 11.85 wt. %, and the residual oxygen content can be reduced to 0.25 wt. %. By sintering, the density of the alloy can reach 5.92 g/cm3.

Synthesis of Al2OC Ceramic Powder by a Carbothermal Reduction Process

2014 ◽  
Vol 881-883 ◽  
pp. 1017-1020
Author(s):  
Shuang Shuang Ding ◽  
Peng Cui ◽  
Hong Xi Zhu ◽  
Cheng Ji Deng ◽  
Chao Yu
Keyword(s):  
Carbothermal Reduction ◽  
Raw Materials ◽  
Heating Temperature ◽  
Ceramic Powder ◽  
Reduction Process ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Argon Flow ◽  
Micro Morphology

A12OC ceramic powder was successfully synthesized via a carbothermal reduction method using Al2O3, B2O3 and activated carbon powders as raw materials. The effects of synthesis temperature on the phase transformation and micro-morphology of A12OC were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the content of A12OC in the products was increased with the increasing heating temperature. The optimized process for preparing A12OC was heating the mixtures at 1700 °C for 2 h in argon flow. A12OC particles synthesized at 1700 °C were hexagon plate-like with thickness of 5 μm and size of about 50 μm. Keywords: A12OC, synthesis, microstructure

Study on Direct Reduction Process of Cylindrical Briquetting Hematite

2020 ◽  
Vol 988 ◽  
pp. 36-41
Author(s):  
Andinnie Juniarsih ◽  
Anistasia Milandia ◽  
Actur Saktianto ◽  
Suryana
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Iron Ore ◽  
Raw Materials ◽  
Direct Reduction ◽  
Reduction Process ◽  
Iron And Steel ◽  
Direct Reduction Process ◽  
Rate Study

There are two types of iron resources such as primary iron ore and iron sand. In general, primary iron ores use as raw materials in iron and steel making and can reduce directly. In Direct reduction process, Fe2O3 (hematite) is converted to metallic iron by the removal of oxygen. This work presents a heat transfer rate study for direct reduction process of iron ore cylindrical briquette. An investigation has been carried out of different reduction parameter such as different sizes cylindrical geometry over temperatures ranging from 700°C to 1100°C for reaction time from 10 minutes to 1 hour. The result was indicated that the value of the heat transfer rate decreases in the core and outer parts of the cylinder briquettes.

Reaction Mechanism of Siderite Lump in Coal-Based Direct Reduction

2016 ◽  
Vol 35 (2) ◽  
pp. 185-194 ◽  
Author(s):  
Deqing Zhu ◽  
Yanhong Luo ◽  
Jian Pan ◽  
Xianlin Zhou
Keyword(s):  
Reaction Mechanism ◽  
Magnetic Separation ◽  
Iron Ore ◽  
Direct Reduction ◽  
Reduction Rate ◽  
Reduction Process ◽  
X Ray Diffraction ◽  
Transfer Resistance ◽  
X Ray ◽  
Rate Controlling Step

AbstractSiderite is one of the significant iron ore resources in China and yet is difficult to upgrade by traditional beneficiation processes. A process of coal-based direct reduction–magnetic separation was successfully developed for the beneficiation of siderite. However, few studies have thoroughly investigated the mechanism of the direct reduction of siderite. In order to reveal the reaction mechanism of coal-based direct reduction of siderite lump, thermodynamics of direct reduction was investigated with coal as the reductant. The thermodynamics results indicate that coal-based direct reduction process of siderite lump at 1,050°C follows the steps as FeCO3→ Fe3O4→ FeO → Fe, which is verified by chemical titration analysis, X-ray diffraction and scanning electron microscope. The microstructure of siderite sample varies with different reduction stages and some 45% porosity induced by thermal decomposition of siderite is conductive to subsequent reduction. The conversion of FeO to Fe is the main reduction rate-controlling step. The reduced product with the metallic iron size over 30 μm can be effectively beneficiated by wet magnetic separation after grinding. The obvious layered structure of reduced product is due to different heat transfer resistance, CO and CO2 concentration.

Analysis of Cylindrical Briquette Dimension on Total Iron Content and the Degree of Metallization in Direct Reduction Process of Iron Ore and Iron Sand Mixture

2019 ◽  
Vol 964 ◽  
pp. 19-25 ◽  
Author(s):  
Fakhreza Abdul ◽  
Sungging Pintowantoro ◽  
Alief Bram Hidayatullah
Keyword(s):  
Gas Flow ◽  
Iron Ore ◽  
Raw Materials ◽  
Direct Reduction ◽  
Reduction Process ◽  
Total Content ◽  
Outer Diameter ◽  
Direct Reduction Process ◽  
Sand Mixture ◽  
Fe Content

Indonesia has abundant resources or raw materials, especially the iron sand raw materials. But, the iron sand processing in Indonesia is still low. Even though, the steel demand in Indonesia is still high. So, the iron sand processing product as raw materials in steelmaking is the solution of it. In this research, the study was conducted by using the variation of briquette dimension of mixture of iron sand and iron ore in Direct Reduction process. The aim of this research is to study the effect of briquette dimension on Fe content and degree of metallization of the Direct Reduced Iron (DRI). First, the iron sand and iron ore were crushed and shieved until pass the 50 mesh standar size. Then, iron sand and iron ore were mixed and briquetted based on the variation of dimension. There are three variations of briquette dimension. Then, the briquettes was reduced at 1250°C for 12 hours. The reduced briquettes then were analyzed using XRD, XRF and degree metallization calculation. The result showed that the dimension of briquette affect the Fe content and the degree metallization of DRI. The dimension of briquette will affect the reductor gas flow in the crucible, so the rate and direction of reduction process of iron oxide will be affected too. The best briquette is Briquette B (7.9 cm for inside diameter, 15.1 cm for outer diameter and 19.5 cm for the height), with 75.02% for Fe total content and 66.52% for degree of metallization. This was due to The briquette B has the most evenly diffused dimension either vertically and horizontally.

Formation Mechanism of Soot in Zinc-Bearing Dusts Direct Reduction Process

2010 ◽  
Vol 156-157 ◽  
pp. 817-823 ◽  
Author(s):  
Xue Feng She ◽  
Qing Guo Xue ◽  
Hui Xian Yang ◽  
Yin Gui Ding
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Direct Reduction ◽  
Reduction Process ◽  
Rotary Hearth Furnace ◽  
X Ray Diffraction ◽  
Hearth Furnace ◽  
Direct Reduction Process ◽  
X Ray ◽  
Scanning Electron

The high-temperature tube furnace was applied to simulate the rotary hearth furnace (RHF) for the direct reduction of the zinc-bearing dusts from steel plants. The soot generated in the direct reduction process was studied by chromatography, X-ray diffraction (XRD), .and scanning electron microscopy (SEM) etc. The results suggested that the main phases of the soot were ZnO, KCl, NaCl and Zn5(OH)8Cl2H2O. Furthermore, the contents of Zn reach to 64.2% which could be used as secondary resources for zinc making. It is concluded that KCl and NaCl resulted from the volatilization from the briquettes at the experimental temperature of 1573K, while the ZnO were produced by the oxidation of the Zn vapor reduced from briquettes.

scholarly journals Structure and Phase Changes of Nickel Slag in Oxidation Treatment

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 313
Author(s):  
Xiaoming Li ◽  
Xinyi Zhang ◽  
Xuyuan Zang ◽  
Xiangdong Xing
Keyword(s):  
Phase Composition ◽  
Direct Reduction ◽  
Reduction Process ◽  
Isothermal Oxidation ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
Subsequent Reduction ◽  
Transfer Resistance ◽  
Oxidation Treatment ◽  
X Ray

To overcome the difficulty in the direct reduction of Fe2SiO4 in nickel slag, the isothermal oxidation of the nickel slag was conducted between 300 and 1000 °C. Its morphology and phase composition after oxidation at 300–1000 °C for 5–30 min are analyzed by means of Scanning electron microscopy, X-ray diffraction, and thermodynamic calculation. The results show that oxidation can effectively promote the transformation of Fe2+ into Fe3+ in nickel slag. At 900 °C, the oxidation rate of element Fe reaches 95%. Fe2+ in Fe2SiO4 is oxidized to generate Fe2O3, and the unit cell volume decreases from 301.75 Å3 to 297.72 Å3 with the increase in temperature. At the same time, a large number of pores appear in the particle, which reduces the mass transfer resistance of gas in the particle during the reduction process, accelerates the reduction speed, and is conducive to strengthening the reduction. Therefore, the oxidation treatment of nickel slag can improve its phase composition, thus benefiting the subsequent reduction.

scholarly journals Preparation of high quality ferrovanadium nitride by carbothermal reduction nitridation process

2017 ◽  
Vol 53 (3) ◽  
pp. 383-390 ◽  
Author(s):  
Y.D. Wu ◽  
G.H. Zhang ◽  
K.C. Chou
Keyword(s):  
Nitrogen Content ◽  
Carbothermal Reduction ◽  
Raw Materials ◽  
Great Influence ◽  
Carbon Diffusion ◽  
Phase Evolution ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
High Quality ◽  
Nitridation Process

High quality ferrovanadium nitride was prepared successfully by carbothermal reduction nitridation process by using V2O5 and Fe as the raw materials. The effects of reaction temperature and C/O molar ratio (content of O is defined as the oxygen in V2O5) on the quality of ferrovanadium nitride were investigated in detail. It was demonstrated that C/O molar ratio had a great influence on the residue carbon, as well as the nitrogen content in the final products. It was found that the nitrogen content of the final product achieved 11.52% when the C/O molar ratio was 90% of the stoichiometric value. However, the nitrogen contents of the final products decreased with the further increase of C/O molar ratio. For the temperature higher than 1773 K, Fe became liquid phase and surrounded the solid V(C, N, O) particles tightly. The formation of liquid Fe was beneficial for the further removal of oxygen atoms left in the V(C, N, O) lattice, since it provided a liquid tunnel for carbon diffusion which greatly enhanced the reaction kinetics. From the results of X-ray diffraction (XRD) and thermodynamic calculations, phase evolution sequence of V2O5 can be obtained as: V2O5?VO2?V2O3?V(C, N, O). Moreover, the kinetic process from V2O3 to VN was studied and the results shown that the reaction rate can be described by Jander diffusion model with the extracted activation energy of 188.173 kJ/mol.

ON THE PROCESSING OF HEMATITE RAW MATERIALS AT THE KRYVOROZHSK MINING AND PROCESSING PLANT OF OXIDIZED ORE ON TECHNOLOGY OF DIRECT RECOVERY ITmk3

2018 ◽  
pp. 32-37
Author(s):  
P.I. Loboda ◽  
Younes Razaz ◽  
S. Grishchenko
Keyword(s):  
Magnetic Properties ◽  
Cast Iron ◽  
Iron Content ◽  
Raw Materials ◽  
Direct Reduction ◽  
Processing Plant ◽  
High Iron Content ◽  
High Iron ◽  
Direct Restoration ◽  
First Time

Purpose. To substantiate the efficiency of processing hematite raw materials at the Krivoy Rog Mining and Processing Plant of Oxidized Ores using the direct reduction technology itmk3®. Metodology. Analysis of the results of the itmk3® direct restoration technology developed by Kobe Steel Ltd., Japan and Hares Engineering GmbX, Austria, with a view to using it to process Krivbass hematite ores into granulated iron (so-called “nuggets”). Findings. The involvement in the production of hematite ores (oxidized quartzite) of Krivbass with high iron content, but with low magnetic properties for their processing into granular cast iron is grounded. Originality. The use of itmk3® direct reduction technology from Kobe Steel Ltd., Japan and Hares Engineering GmbH, Austria for the processing of Krivbass hematite ores into granular cast iron is justified for the first time. Practical value. The efficiency of the use of hematite ores (oxidized quartzite) has been substantiated, which can significantly reduce the costs in the mining cycle for the economical production of metallurgical products.

Sign in / Sign up

Export Citation Format

Share Document