Papers by Keyword: FeO

Abstract: In this project, the permanent magnets ferrites have been prepared by recycle the steel waste product. Steel waste is an impure material that contains the iron oxides and impurities. The steel waste product is a form of flakes is grinding for several hours to form a fine powder. The iron oxides powders are separated from magnetic and non-magnetic particle using magnetic particle separation. The magnetic particles was again been purified by using the Curie temperature separation. The magnetic powder carried out from the purification was heated at 500 °C for 6 hours at 6 °C/ mins to form hematite, Fe₂O₃. The constitute amount of BaCO₃ and Fe₂O₃ derived by steel waste product are mixed by using mechanical alloying to prepare the barium hexaferrites (BaFe₁₂O₁₉). The samples were sintered at different temperature 600/800/1000/1200 °C for 6 hours at 6 °C/ mins. The composition of FeO, Fe₃O₄ and Fe₂O₃ of the steel waste product was carried out using X-ray Fluorescence (XRF) and Energy Dispersive Spectroscopy (EDAX). The crystallography of sample is observed by using X-ray Diffraction (XRD). Microstructure of samples was carried out by using Field Emission Scanning Electron Microscope (FESEM) and Atomic Force Microscopy (AFM). The saturation magnetization, Curie temperature and density are also observed. The results show the purification process yields high purity of hematite, Fe₂O₃. The common characteristics of the steel waste product are its low cost, availability and thus the potential for large production volumes, need for recycling, and tendency to further oxidation in the production of ferrites.

Abstract: Sinter is the main raw material for ironmaking. It is very important to control sinter chemical composition and comprehensive performance. In this paper, a predictive system for sinter chemical composition FeO and the sinter yield was established based on BP neural network, which was trained by actual production data. The MATLAB m file editor was used to write code directly in this paper.The application results show that the prediction system has high accuracy rate, stability and reliability, the sintering productivity was improved effectively.

Abstract: The isothermal transformation of wustite (FeO) in the range of 650~350°C was studied using Gleeble 3500 thermal simulated test machine, electron back-scatter diffraction (EBSD) and scanning electron microscopy (SEM). A wustite layer was initially formed by oxidizing low carbon micro-alloyed steel in air at 880°C for 20 seconds. The layer was then isothermally annealed at 650-350°C in argon for up to 10000 seconds. The transformation of FeO was comprised by a proeutectoid reaction and a eutectoid reaction. FeO initially transformed to Fe3O4 by proeutecioid reaction and then the retained FeO transformed to lamellar mixture Fe+Fe3O4 by eutectoid reaction. The proeutectoid and eutectoid reactions both followed a C-curve trend and the nose temperatures were 475°C and 425°C, respectively. An isothermal transformation (IT) diagram was summarized based on our results.

Abstract: We have studied the equation of states and vibrational properties of FeO using DFT based plane-wave pseudopotential (PW-DFT) within the generalized gradient approximation. The calculated cohesive properties at ambient condition, namely, lattice constant (a₀), bulk modulus (B₀) and its first pressure derivative (), are reported for B1-phase of FeO, in agreement with previous experimental and other theoretical results. A linear-response approach to the density functional theory was used to derive the phonon frequencies and phonon density of state (p-dos). Further, in order to calculate both static and dynamic equations of states, nearest-neighbour second-moment tight-binding energy model (TB-SMA) was used. Parameters of the present TB-SMA model were determined by the present ab initio pseudopotential calculations. It is found that the present simple TB-SMA scheme is able to mimic shock Hugoniot for such oxides correctly.

Abstract: The sintering characteristic and leaching property of calcium aluminates in the CaO-Al2O3-SiO2 system with different FeO additions were investigated. FeO decreases the melting temperature of clinker, and makes the clinker not self-pulverizable. As FeO addition increases from 0 to 4%, the main phases of clinkers sintering at 1350 °C are 12CaO•7Al2O3 and 2CaO•SiO2 as well as some CaO•Al2O3 when the mass ratio of Al2O3 to SiO2 is 5.0 and the molar ratio of CaO to Al2O3 is 1.4. The interplanar spacing of 12CaO•7Al2O3 in the clinker increases with the increase of FeO addition, and the proportion of CaO•Al2O3 in the clinker decreases with the increase of FeO addition. FeO does not affect the Al2O3 leaching rate of clinker obviously, but increases the molar ratio of caustic Na2O to Al2O3 in the leached liquor.

Abstract: The main objectives of this work are to experimentally examine the enhancing mass transfer performance of FeO nanofluid on the bubble absorption and to find the optimal method to design highly effective compact absorber for NH₃/H₂O absorption refrigerator. Based on the microcosmic analysis of the factors affecting the stable performance of nanofluid, FeO nanofluid was prepared by using the ultrasonic dispersion method. The ammonia bubble absorption experiments with FeO nanofluid were carried out and the data of absorption height were acquired. The results showed that FeO nanofluid had an enhancing effect on mass transfer performance, and the absorption height was 2mm higher than that of the water based solution in 2 minutes of the experiment conditions. The curves of the solution temperature in absorption were also given. According to the data of the absorption height and the solution temperature, it is pointed out that there are two factors which might have negative influences on the mass transfer enhancing process.

Abstract: The oxidation behavior of Fe–Si alloys at 1073K in air was investigated. The oxidation kinetics described by the parabolic rate law of diffusion controlled oxidation and the oxidation rate decrease with the increasing Si content. Fe-Si alloys were oxidized for different times at 1073K to obtain the same scale thickness of approximately 30μm. Observations of scale cross-sections indicated the structure of oxide scale and elemental distribution in oxide scales strongly depends on Si content. The oxide scale on Fe-Si alloys with low Si content consisted of three layers with an outer Fe₂O₃, an intermediate Fe₃O₄ and an inner FeO and some voids were formed in Fe₃O₄ and FeO layers. The Si-rich oxide layer was formed at the scale/alloy interface of Fe-Si alloys with high Si content. Furthermore, the amount of internal oxidation zone increased with the increasing Si content. Observations of scale cross-sections indicated that the structure of oxide scale and elemental distribution in oxide scale strongly depend on Si content.

Abstract: One method for lining the inner surface of a steel cylinder with copper alloy is to pour molten copper alloy into a heated cylinder, which has been previously filled with borax anhydride. This process replaces the molten borax anhydride with molten copper alloy. After the cylinder is cooled, the embedded copper alloy is drilled along its center axis so that a prescribed thickness of the copper alloy may remain. However, when the cylinder is made of cast iron including high concentration of carbon, the copper alloy does not bond to the inner surface of the cylinder. To solve this problem, we investigated to utilize the decarburization phenomenon. Two methods were investigated. In one method, the cast iron cylinder filled with FeO powder is heated at a high temperature so that the carbon precipitates in the cast iron may get out through reaction with O2 formed by decomposition of FeO. In the other method, the cast iron cylinder is only heated in air. A decarburized layer is formed beneath an oxide layer. In both methods, the lining of cast iron with copper alloy was attained.