Papers by Keyword: Fe

Abstract: The iron, residue valuable metal in the zinc-volatile kiln slag, has its own characteristics of complex mode of occurrence, the relative high content and difficult recovery. Based on the differences in magnetism and specific gravity between iron rich part and carbon rich part, integrated to the water waste problem through current dry process to recover iron, ribbon, a complete set of all dry beneficiation process had been developed. It included: microwave drying, coarse crush---pre-screening technology, mid crush---fine crush technology, two parts---three steps magnetic separation to produce Fe powder, four steps magnetic separation and air medium re-election of carbon powder processing steps. Meanwhile, it carried out a reasonable selection for the crush equipment and gravity separation equipment. And it developed a new type of magnetic separation equipment. They enable a more uniform particle size and a higher grade and recovery of Fe and carbon powder, as well as lower energy consumption and higher production efficiency advantages. The zinc-volatile kiln slag is promoted to be a further recycling, finally.

Abstract: Rolling of Al-Mg-Al tri-layer composite material fabricated by the explosion cladding method was simulated using finite element methods. The rolling temperature was determined based on the flow stresses of AZ31 magnesium alloy and 7075 Al alloy at elevated temperature. The strain distribution in the plates during rolling and effects of the reduction ratio on the separation in the Al/Mg/Al laminate were studied. The simulation agrees with experimental results.

Abstract: Solid phase high energy mechanochemical interaction of α-Fe2O3(hematite) and Fe in powder mixture have been studied. The formation of amorphous iron-based magnetic phase in this process was detected by means of Mossbauer spectroscopy and magnetic measurements. The amount of this phase increases with Fe addition in reduced mixture. Its thermal stability have been studied by magnetic and DCS measurements at constant α-Fe2O3 and gradually increased Fe concentrations.

Abstract: The warm compaction process is simulated by the finite element analysis software which is MSC/MARC. The thermal mechanically coupled analysis method is applied based on the updated Lagrangian Method to simulate powder warm compaction process under different frictional condition and different strain rate. The influence of different friction condition and strain rate is researched on the density and the mechanics behavior of powder green. The results indicate that for cylindrical powder metallurgic products, with the increasing of pressing velocity (namely strain rate), work hardening of powder is gradually evident, and leads to larger distribution grads of density and equivalent stress of green. The improvement of friction condition is propitious to reduce the disadvantage of work hardening and improve the uniformity of distribution of density.

Abstract: During the development of an aircraft structure design, designers draw out a skin-stringer panel with a skin pad on the basis of a conventional skin-stringer panel(skin is directly connected with stringer by rivets or there was a sheet betweeen skin and stringers) to reduce the manufacturing cost. In this paper, we calculated the SIF of three kinds of skin-stringer panels by FE. And then, we analyze the damage tolerance of these structures by fortran program. Especially we carried out a crack propagation experiment of a skin-stringer panel with a skin pad and compared it with the results of a static analysis. Finally we researched the influence of the thickness of a skin pad on the damage tolerance. According to the researches above we concluded the advantages of the skin-stringer panel with a skin pad on the damage tolerance, and presented some suggestions about the thickness of a skin pad.

Abstract: The uniform distribution and the stability of the substrate temperature are the most important factors that deeply affect the quality and the growth rate of diamond films. In this paper, cemented carbide cutters were chosen for substrates, the 3D finite element (FE) model of filaments and substrates was developed in ANSYS 8.0, the calculated results show that the substrate temperature is influenced by the filament temperature, filaments diameter, the quantity of the filaments and the distance between the filaments and the substrates. The 3D finite element model of filaments and substrates also provides a basis for selecting the parameters to obtain uniform diamond films in miniature EACVD system.

Abstract: The effectiveness of phosphorus diffusion gettering (PDG) and related segregation coefficients for different metal impurities were measured applying thermal treatments in the temperature range 800-950 °C for different times. We used multi-crystalline and mono-crystalline CZ p-type wafers with different boron concentrations and different levels of dislocations and bulk micro-defects (BMD). In all sample types, for Cu and Ni we found complete gettering in the temperature range investigated. In the case of Fe, the segregation coefficient increases with both increase in temperature and extension of time. The increase is qualitatively changing when going above 900 °C. At 950 °C the segregation coefficient increases faster at shorter diffusion time but at extended diffusion time it increases slower as compared to diffusion at 900 °C. At the same temperature and time of phosphorus diffusion the segregation coefficient is found to be independent of the metal impurity concentration in the range of 1012-1015 cm-3 investigated. We have shown that the presence of BMD and dislocations in bulk silicon does not impede the ability of PDG to completely remove Fe, Ni and Cu metal impurities from the bulk. Further analysis suggests that the PDG has the same gettering efficiency for mono-crystalline silicon and multi-crystalline silicon. We conclude that if any bulk precipitation of Fe, Ni and Cu impurities is present in multi-crystalline silicon it cannot seriously compete with PDG. However we found that increasing the boron concentration in the samples reduces the segregation coefficient of Fe, and this reduction is more severe at lower temperatures. Finally, by applying a post anneal ramp down from 900 °C to 700 °C after phosphorus diffusion, we found that the Fe segregation coefficient increases by a factor of 36 for lightly B doped samples, from 53 to 1919, leading to a significant reduction of Fe in the bulk after 2 hours ramp down anneal.

Abstract: Fe-doped SnO2 nanoparticles have been synthesized by a simple hydrothermal method. After Fe doping, the as-prepared SnO2 samples were calcined at different temperature from 350-800 °C in air for 1 h. The effects of Fe dopant and calcination on the microstructure and optical properties are investigated using X-ray diffraction (XRD), High resolution transmission electron microscopy (HRTEM) , UV-VIS diffuse reflectance spectra (DRS). Results show that the Fe-doped SnO2 crystallites with the rutile phase was directly synthesized during hydrothermal process without calcination. A dramatically red shift in the absorbing band edge was observed with the decreasing crystallite size result from the increasing Fe content.

Abstract: With Ti(OBu)4 as precursor, and HAC as complexing agent, pure and Fe-doped TiO2 gelatins were prepared by sol-gel method. During the process of gel formation, metal ions were dispersed into the porous TiO2 matrix. Then, powders of pure nano-TiO2 and Fe-doped nano-TiO2 were prepared by drying, grinding and calcining at different temperatures. The grain size and phase structure of pure and Fe-doped TiO2 after calcined at different temperatures, were studied by X-ray diffraction (XRD) and Beckman Coulter Sorption Analysis. The results showed that, the Fe3+-TiO2 had better photocatalytic activity in degradation rate of methyl orange under sunlight. The degradation rate was up to 93% as the system was placed under sunlight for 5 h. The optimum calcination temperature for the best catalytic activity was determined to be 500°C, and the mechanism was discussed.

Abstract: In this work, a series of iron-containing zeolitic materials has been tested as heterogeneous catalysts for decomposition of H2O2 and for oxidation of the cationic dye Methylene Blue with H2O2 in aqueous solutions. FeAPO and FeBEA zeolites, synthesized through hydrothermal crystallization of basic hydrogels, and FeY and FeZSM-5 zeolites, prepared by ionexchange procedures, have been studied. The ion exchange with Fe(III) cations was performed from different salt solutions. Fe-exchange procedure carried out in Fe-citrate solution has been identified as an attractive option for the preparation of highly effective FeZSM-5 catalysts in wet oxidation processes. It has been shown that both tetrahedral, framework Fe, and octahedral, extra-framework Fe species incorporated into zeolite structure are catalytically active in wet oxidation reactions.