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By Shen Shen, Paul R. Ohodnicki, Samuel J. Kemion, Vladimir Keylin, Alex Leary, Joseph F. Huth, Michael E. McHenry

"Recent DOE workshops highlight the need for advanced soft magnetic materials leveraged in novel designs of power electronic components and systems for power conditioning and grid integration. Dramatic weight and size reductions are possible in these applications through operating at increased frequencies. This manuscript discusses processing and composition design approaches for optimizing FeCo-based nanocomposites for higher frequency operation at 100 kHz and above. The proposed strategy involves starting with prior compositions known to exhibit high inductions, optimal field crystallization induced anisotropy, and excellent mechanical and high temperature magnetic properties. Proposed alloy modifications for the applications of interest would include increased amorphous phase resistance, optimum induced anisotropy, and minimized or carefully engineered magnetostriction. Relevant process developments would target reduction of ribbon thickness by optimizing the casting process or post-processing treatments such as chemical thinning or rolling. Three archetypes FeCo-based nanocomposites are described including near equiatomic FeCo-based, Fe-rich and Co-rich alloys.MotivationSilicon steels are widely applied for 60Hz utility-scale transformers [1]. For applications at high frequencies, however, Si-steels exhibit unacceptable losses and ferrites are typically used due to their high electrical resistivity and good soft magnetic properties [2]. However, the low inductions offerrites have limited their applications in power electronics. Developments in rapid solidification have led to amorphous metal alloys and controlled nanocrystallization processing has resulted in state-of-the-art amorphous/nanocrystalline nanocomposite soft magnets [3-5]. Commercial utility-scale transformers made with Fe-based amorphous materials have been demonstrated to result in significant energy savings with an associated reduction in greenhouse gas emissions [6]. DOE workshops held in 2010 emphasized a need for advanced soft magnetic materials for the next generation of power electronics. For advanced power conditioning and grid integration applications, frequencies of 20 kHz up to -1 MHz are of interest depending on the power level [7]. Here, we review previous work and discuss the approaches to optimize FeCo-based nanocomposite materials for high frequency applications."

Jan 1, 2012

By A. Galvan

High rate compressible media filter (CMF) tests produced exceptional total suspended solids (TSS) removal at hydraulic loading rates ranging from 97.8 to 122.2 m/h. The compressible media is manufactured from a robust resin fiber that can withstand low pH and temperatures up to 149 °C. The media porosity can be varied by applying compression onto the media. At 40% compression, the CMF can remove particles greater than 4 μ. Three synthetic test-samples were generated by Hazen Research Inc., (Golden, Colorado) to simulate the copper Pregnant Leach Solution (PLS), Raffinate and Electrolyte solutions used for the testwork conducted at their facility. The preliminary results showed that the CMF was very effective in removing TSS without the use of chemical conditioning from the above test-solutions with efficiencies of 98%, 97%, and 96%, respectively. Given the remarkably high hydraulic loading rates, the industrial equipment footprint would be minimized appreciably over conventional clarification and alternative filtration systems.

By O. G. Rivera, R. D. Moser, P. G. Allison, W. R. Whittington, P. Rivera-Soto, Z. McClelland, D. Francis

This research examined the evolving microstructure of quasi-static and dynamically loaded fully annealed metastable 301 austenitic stainless steel (SS). Experiments were performed to an interrupted strain value of 20% and to failure using a tension Kolsky bar (1000/s) and an electromechanical load frame (0.001/s). Electron Backscatter Diffraction (EBSD) identified the microstructural evolution from the as-received condition to the 20% strain level for the high and low rate interrupted samples. This material achieved over 60% elongation to failure with increasing strength as strain rate increased, as expected. Fractography analysis using SEM showed particles in the microstructure and a ductile failure mode. The 301 SS exhibited a greater amount of phase transformation from parent austenite to -martensite at the dynamic strain rate when compared to the quasi-static strain rate during the interrupted experiments. This result is indicative of the increased propensity for austenite to -martensite phase transformations at the high strain rate.

Jan 1, 2016

By Wei-Tong Du, Yu Wang, Gang Wen

Carbon dioxide (CO2), a major component of the greenhouse gases, could be comprehensive utilized as a valuable resource to oxidize vanadium during the converter vanadium extraction process. The thermodynamic software, FactSage, was utilized to study the oxidation ability and theoretical cooling ability of using weak oxidant CO2 as coolant in vanadium-containing hot metal. Besides, experimental research on vanadium extraction in CO2 and O2 mixed blowing extracting process had been undertaken. The results indicated that the elements C, Si, V, Mn etc. could be oxidized by weak oxidant CO2, and the content of V2O3 in slag was approached to pure O2 blowing. Furthermore, CO2 had a remarkable cooling ability and the molten bath temperature kept on decreasing as CO2 blowing rate increases. This research has proved that CO2 and O2 mixed blowing in vanadium extraction process are effective.

Jan 1, 2015

By P. Tim Johnson

Relentless increases in demand for nickel and vanadium for uses such as steelmaking, catalysts and battery materials, plus the growing financial and environmental costs of their primary extraction, have led to much interest in potential secondary sources of these metals. The presence of such metals in heavy fuel oils, bitumen and related materials offers both opportunities and challenges for potential extraction methods, especially with the growing production and importance of metal-rich fossil fuels around the world. For several decades, Tetronics’ DC plasma smelting technology has been used for the recovery of metals such as nickel and chromium from stainless steel melt dusts and other wastes in compact, environmentally-friendly and efficient plants. This paper explores the suitability of DC plasma smelting as part of a wider flowsheet with feed preparation and aluminothermic reduction techniques for smaller-scale extraction operations based on this important niche secondary source of these key metals.

By Robert F. Jenkins, King G. Robertson

This paper presents a practical approach for utilizing a computer model to determine the mass balance for a typical UBC recycling complex - starting with raw materials input, through scrap preparation, delacquering, melting, alloy adjustment and casting. This model is especially concerned with metal unit losses throughout the recycling complex with emphasis on metal losses at the melting furnace. The model also addresses the application of hardener alloys, metallurgical salts, chlorine for demagging, and reagents for acid gas emissions control. Other issues addressed are dross generation, acid gas emissions and dirt and fines to landfill. One benefit of the model is the conversion of annual production objectives to hourly production rates and resource requirements taking into account production schedules, maintenance downtime, and operations inefficiencies.

Jan 1, 2000

By Sabine Knoll

The thermodynamic properties of four liquid ternary zinc alloys, Au-Sn-Zn, Ag-Sn-Zn, AI-Sn Zn and Cu-In-Zn were measured with an electromotive force (emf) method at three or four cross-sections with an constant X:Sn or Cu-In ratio. At the Au-Sn-Zn and AI-Sn-Zn system calorimetric measurements were also carried out in order to compare the integral enthalpy of mixing from the direct measurements with the data of the emf measurements, which were derived by Gibbs-Duhem integration.

Jan 1, 2003

By Sabine Knott

The thermodynamic properties of four liquid ternary zinc alloys, Au-Sn-Zn, Ag-Sn-Zn, AI-Sn- Zn and Cu-In-Zn were measured with an electromotive force (emf) method at three or four cross-sections with an constant X:Sn or Cu-In ratio. At the Au-Sn-Zn and AI-Sn-Zn system calorimetric measurements were also carried out in order to compare the integral enthalpy of mixing from the direct measurements with the data of the emf measurements, which were derived by Gibbs-Duhem integration.

Jan 1, 2003

By Jan Petter Maehlen

Solid H-absorbing materials are in focus of ongoing R&D to offer viable solutions for the hydrogen storage and supply systems aimed on use of hydrogen as energy carrier for automotive transportation. Low operating pressures, combined with high gravimetric and volumetric efficiencies, together with fast kinetics of hydrogen release at ambient temperatures (providing conditions for a low energy loss due to decomposition), are the most important features of the ?ideal? H storage material. Hydrides of the light elements are the only possible candidates to build systems with an overall efficiency similar to those accommodating liquid or compressed (700 bar) hydrogen. One promising material from this point of view is aluminium trihydride, alane AlH3 with a gravimetric storage capacity of 10 wt.% H. This work was focused on studies of the crystal structure and thermal decomposition of alane by application of powder synchrotron X-Ray diffraction.

Jan 1, 2006

By Chao Li, Lim Hongxu, Yuyue Wang, Xie Yang

"A intergrated process of sulfuric acid leaching, sodium chloride leaching, lead chloride crystallization, lead hydroxide synthesis and roasting was carried out for the recovery of lead, cadmium, copper and zinc from lead smelting dust containing various metals. The results showed that the separation of cadmium, zinc and copper from dust could be obtained after sulfuric acid leaching and corresponding leaching rate were 92.12%, 90.25% and 88.26% respectively. The subsequent sodium chloride leaching carried out for lead with optimized parameters as: sodium chloride concentration 250g/L, leaching temperature 90°C, leaching time 2h, pulp density 33g/L, 0.12mol/L CaCh; The lead compounds crystallization rate reached 86.67%, and then transferred into mPbO·nH2O, the product of 98.66% ß-PbO could be obtained through roasting under 502°C. In the end, a feasible method of ß-PbO preparation from lead containing dust was put forward.IntroductionThe pyro-metallurgy flue dust from smelting lead activities are often stockpiled and pose potential environmental risks due to the heavy toxic elements, such as Pb, Cd, As, Cu, Cl, and Zn which are contained in the dust. With the rapid depletion of rich ore resources in recent years, it has become increasingly more financially attractive to recover valuable metals from previously stockpiled dust, while simultaneously reducing the potential of environmental pollution from toxic elements contained in the dust. Nowadays, pyro-metallurgical and hydrometallurgical routes or both combined methods can be developed to treat secondary materials such as lead ash, leach residues etc. By comparison the hydrometallurgical processes are often considered more eco-friendly.Some chloride leaching processes for recovering lead have been employed using either NaCl, or MgC2 and CaCl2, or FeCl3 [1] The effectiveness of the brine leaching method is based on the formation of complex metal chlorides in concentrated chloride solutions [2] Similarly, Other metals such as zinc, cadmium and copper contained in the flue dust are often treated with sulfuric acid, hydrochloric acid, ammonium solution and sodium hydroxide etc. as lixiviants [3] The metals from leach solutions thus has been obtained by precipitation, ion exchange, solvent extraction or replacement [4]"

Jan 1, 2014

By Leszek Hoser

Polycrystalline oxide superconductors that have the perovskite structure, that are oxygen deficient, and that have compositions based. on the so-called. 1-2-3 (YBa2Cu3O7) compound, were investigated.. The materials exhibit a high critical transition to superconductivity at temperatures near 90oK. It was determined that maintaining the oxygen content within the correct range in connection with an appropriate amount of CU ions in the crystal lattice leads to high-critical temperature (Tc:) superconducting properties. High-Tc: superconductors with a critical temperature in the range of 100°K were developed. Further investigations, based. on the theoretical examinations of the origin of superconductivity, have been performed and are discussed..

Jan 1, 1989

By Miguel N. Herrera

The electrochemistry of coal pyrite is relevant to coal desulfurization by chemical or bacterial leaching, flotation and oil agglomeration. The electrochemical behavior of polished and etched Upper Freeport and Pittsburgh coal pyrite samples was investigated from pH 1.0 to 10.5. The open-circuit potentials decreased with increasing pH, as expected, but were well above the thermodynamic stability region of pyrite, and decreased with time. Cyclic voltammetry revealed behavior highly sensitive to pH and scan rate (2.0 and 20.0 mV/s). The behavior on the first cycle was always substantially different from that on subsequent cycles. The anodic and cathodic reactions were correlated with the Eh-pH diagram for the Fe-S-H20 system to identify the reactions occurring at different pH values. There was also evidence that the buffers used to maintain basic pH values are themselves electrochemically active, which should be considered in interpreting many earlier electrochemical studies of sulfide minerals.

Jan 1, 1994

By Guangqing Zhang

The paper presents results of a systematic study of synthesis of titanium oxycarbide and its chlorination. Titanium oxycarbide was produced by carbothermal reduction of titania in hydrogen, argon and helium. Formation of titanium oxycarbide started at 1200°C in all gases. The reduction was the fastest in hydrogen. Formation of titanium oxycarbide in hydrogen was close to completion in 120 min at 1300°C, 60 min at 1400°C and less than 30 min at 1500°C. Reduction in argon and helium progressed at a similar rate and reached 90-95% after 300 min at 1400-1500°C. The chlorination of titanium oxycarbide was ignited at 150-200°C. Chlorine partial pressure and gas flow rate strongly affected the chlorination rate. Chlorination of titanium oxycarbide produced with carbon to titania molar ratio 2.5 at 235-400°C was close to 100% in 30 min.

Jan 1, 2009

By K. Murayama, M. Kawakami, T. Takenaka, S. Yokoyama

"Cokes play an important role of spacer in blast furnace. However, they degenerate during Boudouard reaction. Blast furnace cokes are reacted with pure C02 at I 072 to 1673 K. Reaction rate was obtained by the weight change of spherical specimen. The specimen after reaction was examined by microscopic observation. The reaction rate increased with temperature and was expressed by two Arrhenius type lines. The activation energy was 126 KJ/mol at higher temperature than 13 73 K and 202 KJ/mol at lower temperature range. At the higher temperature range, the reaction proceeded from the surface leaving unreacted core, whereas homogeneously whole inside at lower temperature. The porosity increased from the center to surface at higher temperature, whereas it was almost constant at lower temperature.IntroductionThe cokes have the function of fuel, reductant and spacer to keep gas and liquid flow in the blast furnace. Thus, the reaction mechanism of coke with several gas and the strength after the reaction should be important factor to control the blast furnace operation. The reaction mechanism of coke with C02 has been studied extensively. The rate equations were derived by Gadsby[ I], Ergun[2] and Turkdogan and Vinters[3]. They were compared and discussed by Kobayashi and Omori [ 4]. Effect of crystallization degree on the reaction rate was examined by Kashiwaya and Ishii[5]. Catalytic enhancement effect of ash componets have been clarified by Kashiwaya et. al. [6]. Although degradation of coke in blast furnace has been examined recently[7], however, the degradation of coke after the reaction with C02 has not been well clarified yet. In the present work, the metallurgical coke specimen was heated in N2 and C02 and the reaction mechanism and degradation behavior after the reaction was investigated."

Jan 1, 2000

By Pranav Deshpande

The wear behavior of metal matrix composites differs from that of the monolithic metallic counterparts because composite materials have multiple constituents in their structures and these constituents wear at different rates. It was observed that under low wear stresses, abrasive wear prevailed. As the wear stress increases, pullout of reinforcement occurs and both abrasive wear and wear due to pullout contribute to the overall composite wear. A model of wear taking into account both types of wear has been developed. A critical pullout wear stress was suggested for each composite. Below the critical wear stress, no pullout of reinforcement occurs. It turns out that the critical wear stress simply equals to the ratio of the interfacial strength between the matrix and the reinforcement to the friction coefficient between the reinforcement and the wear counter surface. The critical wear stress is independent of the particle size of the reinforcement. From data on wear of 53% WC composites, the equation of wear for 32% WC composites was obtained. Experimental results agreed well with the predicted wear rate of this composites. This provides an excellent verification of the wear model developed by Lin and Deshpande. Wear data from Modi et al. in the literature were also perfectly fitted with the model.

Jan 1, 2006

By Sergio N. Monteiro

Wastes generated by our society and the question on how to dispose them is, nowadays, a relevant matter of concern. The objective of the present work was to characterize the technical properties of composites made of discarded jute sackcloth with its coarse wove fabric, serving as reinforcement phase, and polyethylene wastes collected from city dumps, as continuous matrix. Different amounts, up to 30 wt.% of jute plain weave, fabric were press molded at 160°Ctogether with sieved polyethylene particles. The resulting composites displayed mechanical properties that could compete with those of low-density wooden board. Both by presenting a solution to, otherwise, disposed wastes and by helping to prevent deforestation, the investigated composite may be regarded as an environmentally correct material.

Jan 1, 2006

By A. Mezei

Samples of cobalt and bismuth concentrates produced from the NICO deposit in Northwest Territories were subjected to a comprehensive metallurgical testwork consisting of: pressure oxidation, ferric chloride leach and carbon in leach, to recover the cobalt, bismuth and gold, respectively. A specific testwork program was designed to allow for the optimization of process parameters under multiple restrictive criteria. The overall objective was to establish leaching sequences that could produce acceptable recoveries while generating environmentally disposable residues as well as solutions suitable for further processing. The recoveries for the leaching stage, under the optimum conditions, were 97% for cobalt and 95% for gold, in the case of the cobalt concentrate. The bismuth concentrate produced recoveries of 99% for bismuth, 99% for cobalt and 97% for gold, respectively

Jan 1, 1999

By Pratheesh George

Solid state galvanic cell with CaF2 as the electrolyte was employed for determining the thermodynamic properties of Nb-Al binary alloys in the temperature range of 973-1073 K. The activities and activity coefficients of Al in NbAl3 were determined. The experimental procedure and the design and construction of the experimental setup have been also explained in detail. Aluminum activity in NbAl3 increased with increase in temperature and shows a strong negative deviation from ideality. The activities of aluminum in NbAl3 were determined to be 0.0165 and 0.0289 at 973 and 1073 K respectively. The stability of NbAl3 has been compared with other available intermetallic systems.

Jan 1, 2006

By I. Goy D. Gaballah

Decontamination of synthetic K2Cr2O 7 solutions containing 10 to 1000 ppm of hexavalent chromium using chemically treated barks have been studied at a laboratory scale. Metal removal from solutions depends on the pH, the initial concentration and the bark species. The use of a pulp density of 2 % in an agitated flask at the optimum pH for 2 hours leads to a percentage chromium removal of about 95 of the initial metallic ions content. Other trials conducted by column percolation permit the determination of the maximum retention capacity of the treated bark. Depending on the bark species, oak or pine, the rate of saturation is 110 and 215 mg of Cr per gram of bark respectively. The incineration of the metal charged barks gives recyclable, ashes containing 36 and 54 % of chromium metal for the oak and pine barks respectively. Experiments, of Cr6+ removal from industrial effluents containing up to 1800 ppm have been carried out on the semi-pilot plant scale. They have lead to the elimination of about 90 % of hexavalent chromium from this industrial waste solution. Further studies are conducted in order to define the hexavalent chromium binding mechanisms on bark constituents.

Jan 1, 1992

By Chen Dong, Yuanling Gao, Jilai Xue, Jun Zhu, Luxing Feng

"Porous Ni-Ti alloy has many applications in a wide range of engineering areas. The porous NiTi alloys were prepared from Ti and Ni powders in sintering process under argon atmosphere. The major chemical compositions of the sintered Ni-Ti body were Ni Ti, Nh Ti4O and Nh Ti, respectively, the internal pore structures were characterized by image analysis technique, which were dependent on various processing parameters such as sintering temperature, amount of poreforming agent, forming pressure, etc. The results show that the porous alloy samples had the characteristics of uniform pore and high open porosity; pore-forming agent and sintering temperature are important factors in porous; pressure affected the sintered products' pore, by affecting the combination of alloy powder with pore-forming agent.IntroductionPorous Ni-Ti alloy materials exhibit not only excellent shape-memory and superelasticity, high yield strength and ductility, good corrosion resistance and biocompatibility, but also have low density, low stiffness, and high energy absorption rate due to their porous structures [1]. In recent years, these porous Ni-Ti alloys have found applications in a wide range of engineering areas, such as bone implants [2-4], impedance-matching connectors [5], energy-absorbing structures [6,7], separators [8] and actuators [9], etc.Pore characteristics can play very important role in determining of the performance of porous NiTi alloys. For example, when the alloys are used to repair or replace hard tissue implant material, the pore shape and size not only determine their mechanical properties, but also have great effect on the fluid transmission of human body. The pore characteristics can also influence the stressstrain behavior of the porous Ni-Ti alloy and, thus, strongly affect their mechanical properties, superelasticity, and fracture mechanisms [10].In this study, the Ni-Ti alloys with high porosity were prepared in a powder sintering process under argon gas. The pore characteristics were investigated using SEM, XRD and image analysis techniques, especially in association with the content of pore-forming agent, sintering temperature and compacting pressure."

Jan 1, 2011