Analysis of Material Containing a Mixture of Metallic Iron and Iron Oxides.

1925 ◽  
Vol 17 (12) ◽  
pp. 1261-1262
Author(s):  
Henry C. M. Ingeerg
Keyword(s):  
Iron Oxides ◽  
Metallic Iron

Microstructure, Stiffness and Corrosion of Bare and Phosphated Specimens Made by Sintering of Structured Iron-Iron Oxide Spheres

2020 ◽  
Vol 405 ◽  
pp. 411-416
Author(s):  
Miriam Kupková ◽  
Martin Kupka ◽  
Renáta Oriňáková ◽  
Radka Gorejová
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Metallic Iron ◽  
Galvanic Corrosion ◽  
Iron Phosphate ◽  
Reduction Reaction ◽  
Diffusion Control ◽  
Iron Oxide Particles ◽  
Flow Through ◽  
Iron Iron

Granulated iron oxide particles were incompletely reduced to structured particles comprised metallic iron and residual iron oxides. Structured particles were pressed into prismatic compacts and sintered. Some of sintered specimens were subsequently phosphatized and calcined. Specimens with an iron phosphate coating were found stiffer than specimens without coating. In Hanks' solution, a galvanic corrosion was induced by more noble iron oxides coupled to a less noble metallic iron. This could explain higher corrosion potentials and higher rates of iron dissolution in comparison with a pure iron. The coating of specimens with iron phosphates shifted corrosion potentials towards more negative values and slowed down the dissolution of iron. This was most likely caused by a reduction in oxygen flow through the coating to iron-oxide cathodes, which has enhanced the influence of diffusion control on the kinetics of reduction reaction.

scholarly journals Effect of the reaction of ammonia gas on the swelling of metallic iron and its oxides during nitriding processes

Athenea ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 38-45
Author(s):  
Oscar Dam G. ◽  
Luis Azocar
Keyword(s):  
Iron Oxides ◽  
Metallic Iron ◽  
Swelling Behavior ◽  
Test Scheme ◽  
Volume Changes ◽  
Ammonia Gas ◽  
Ore Pellets ◽  
Materials Engineering ◽  
Magnetite Pellets ◽  
Institute Of Technology

In order to study the relationship and effect of nitrogen gas in the reducing gases used in the reducibility tests of iron oxides, under isothermal conditions, a test scheme was executed using ammonia gas, such that its decomposition of the gas in the reactor produced a mixture of H2 and N2 gases. Furthermore, the addition of 6% NH3 in a 28% H2 and 68% N2 gas stream was planned to obtain a gas composition of 70% N2 and 30% H2. This would allow comparing the reducibility curves between both conditions, assuming that the possible difference between both conditions to compare the volume changes of the reduced samples. The difference to be studied will be based on the estimation and comparison of the rate of formation of metallic iron in the stages of reduction of Hematite / Magnetite / Wustite (FeO), as well as the effects of nitrogen absorbed by the fresh metallic iron produced, or present. in iron catalysts to produce ammonia, from the reducing gas mixture, on the volume change of the samples. Likewise, the catastrophic volume changes caused by nitrogen are compared by comparing sources of this gas in solid carbonaceous reducers. Keywords: Gaseous Reduction, Direct Reduced Iron, isothermal tests. References [1]O. Dam G. “The Influence of Nitrogen on the Swelling Mechanism of Iron Oxides During Reduction”. Univ. of London. PhD Thesis 1983. [2]J. Bogde. “Thermoelectric Power Measurements in Wustite. Univ. of Michigan”. 1976. [3]O. Dam G. y J. Jeffes. “Model for the Assessment of Chemical Composition of reduced iron ores from single measurements. Ironmaking and Steelmaking”. Vol. 14, N`5. 1987. [4]M. Yang. “Nitriding-Fundamentals, modelling and process optimization”. Tesis PhD. Worcester Polytech Institute. 2012. [5]EL Kasabgy. T and W-K. LU. “The Influence of Calcia and Magnesia in Wustite on the Kinetics of Metallization and Iron Whisker Formation”. Metallurgical 1980 American Society for Metals and the Metallurgical Society of AIME Volume 11b, pp. 410-414. 1980. [6]“Srikar Potnuru Studies nn the Physical Properties and Reduction Swelling Behavior of Fired Haematite Iton ore Pellets”. MSc Thesis. Department of Metallurgical and Materials Engineering National Institute Of Technology, Rourkela May 2012. [7]R. Agarwal, S. Hembram. “To Study the Reduction and Swelling Behavior Iron Ore Pellets”. BSc. Department of Metallurgical and Materials Engineering National Institute Of Technology, Rourkela May 2013. [8]C. Seaton., J. Foster. and J. Velasco. “Structural Changes Occurring during Reduction of Hematite and Magnetite Pellets Containing Coal Char”. Transactions ISIJ, Vol. 23, 1983, pp. [10]C. Bozco. “Interaction of Nitrogen with Iron Surfaces”. Journal of Catalysis 49. pp16-41. 1977. [11]L. Darken y R. Gurry. “Physical Chemistry of Metals”. Mc Graw hIll . 1953. [12]H. Weirdt and Z. Zwell, Trans. AIME. 229. 142. 1969. [13]J. Schulten. Trans. Soc. Faraday. 53, 1363, 1957. [14]E. Barret y C. Wood. Bureau of Mines R-I 3229. 1934

Effect of Processing Parameters on Aeration of Reduced Hatinh Ilmenite

2016 ◽  
Vol 682 ◽  
pp. 314-320 ◽  
Author(s):  
Thao Thi Nguyen ◽  
Than Ngoc Truong ◽  
Khanh Quoc Dang ◽  
Binh Ngoc Duong
Keyword(s):  
Chemical Analysis ◽  
Iron Oxides ◽  
Flow Rate ◽  
Metallic Iron ◽  
Air Flow ◽  
Weight Ratio ◽  
Processing Parameters ◽  
Air Flow Rate ◽  
Solid Ratio ◽  
Temperature Time

Aeration step, one of the major stages in the Becher process was carried out on reduced Hatinh (Vietnam) ilmenite in NH4Cl solution and the effect of several processing parameters were thoroughly investigated including the temperature, time, liquid/solid weight ratio (L/S), air flow rate and concentration of NH4Cl solution. The obtained results showed that longer rinsing time, higher liquid/solid ratio and air flow rate facilitated metallic iron rusting. The rusted iron amount increased when the temperature increased and reached the highest value at 70°C. Variation of NH4Cl concentration showed similar impact as that of temperature. The highest amount of rusted iron achieved at 0.5% NH4Cl. Chemical analysis and XRD results indicated that 98% of metallic iron in reduced ilmenite has been transformed to iron oxides at an aeration condition (70°C, 8 h, L/S=7/1, air flow rate = 4 l/min and 0.5% NH4Cl). Consequently, TiO2 content from approximately 60% in the reduced ilmenite increased up to approximately 80% in the aerated rutile.

scholarly journals Study on the corrosion of refractory materials by coal blended with the extraction residue of direct coal liquefaction in a simulated gasification atmosphere

Clean Energy ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 731-740
Author(s):  
Baozi Peng ◽  
Shixian Zhao ◽  
Zhen Liu
Keyword(s):  
Iron Oxides ◽  
Metallic Iron ◽  
Molten Slag ◽  
Economic Value ◽  
Coal Liquefaction ◽  
Refractory Materials ◽  
Refractory Brick ◽  
High Iron Content ◽  
Term Operation ◽  
Direct Coal Liquefaction

Abstract Utilizing the extraction residue (ER) of direct coal liquefaction residue as a gasification feedstock has significant economic value. But the characteristic of high ash and iron in the ER would increase the risk of corrosion of the refractory materials and affect the long-term operation of the gasifier. In this work, corrosion experiments of molten slag derived from a mixture of 20 wt% ER and 80 wt% coal on a high-chromia refractory brick and SiC brick were carried out using a rotary-drum furnace in a simulated gasification atmosphere. The experimental results show that the viscosity of the poured slag is larger as compared to the initial ash sample at the same temperature, which suggests that the viscosity–temperature relationship of the poured slag should be used as the reference for the operation temperature of the gasifier to ensure that the slag can flow during operation. For a high-chromia refractory brick, iron oxides in molten slag could react with Cr2O3 in the refractory matrix but, because the aggregate was not found to be damaged, the damage to the matrix structure was the key factor for causing the corrosion of the high-chromia refractory brick. Metallic iron was observed in the exposed SiC brick, which indicated that the reaction between the iron oxides in the slag and SiC occurred, forming metallic iron and SiO2. The corrosion of a SiC brick by molten slag depended mainly on the dissolution of Al2O3 particles and the reaction between iron oxides in the molten slag and SiC particles. Therefore, the high iron content in coal ash had a serious influence on the corrosion of refractory materials. More efforts need to be made on coal blended with ER as a gasification feedstock in the future.

Slags: Descriptions (CJS)

1992 ◽  
Vol 58 (S1) ◽  
pp. 15-21
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Metallic Iron ◽  
Sample Number ◽  
Metallic Inclusions

The following slags are described separately: see also full catalogue in microfiche Table 2. See analyses of each of the following items (with the exo tptioi of nr 69), including occasional metallic inclusions, in microfiche Table 9, where details of sample number and conte... are also given.55. Moderate-sized plano-convex,slag (type 4), with moderate porosity and few charcoal impressions (174 g). Microstructure: moderate-sized semi-dendritic iron-oxide FeO (40-60%) inhomogeneously distributed, in matrix of fayalite and fayalite plus iron oxide pseudo-eutectic. A little ternary glass+fayalite+iron oxide eutectic present. Some regions of pure fayalite; others with large laths of fayalite and iron oxides outlined by giass and iron oxide eutectic. A little metallic iron present.56. Fragment of dense plano-convex slag (50.5 g). Patchily distributed iron oxide (FeO), locally massive (100%), and distorted. Dendrite arm size and spacing varies through fine-moderate-large arms. Matrix of fayalite and unresolved eutectic. A little metallic iron.57. Piece of dense plano-convex slag (37 g). Moderate porosity. Metallic iron common in regions with less iron oxide. There are two regions: one with pools of massive semi-globular FeO with 90+% iron oxide (wustite), interspersed with regions with moderate or fine dendritic FeO in a matrix of unresolved material. Metallic iron contains several percent copper!

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