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By James C. Foley, David K. Rehbein

"In-situ characterizations of green state part density and sintering state have long been desired in the powder metal community. Recent ·advances in non-contact electromagnetic acoustic transducer (EMAT) technology have enabled in-situ evaluations of the acoustic attenuation and velocity as sintering proceeds. Pure aluminum (99.999%) and aluminum alloy powders were prepared with high-pressure gas atomization (HPGA). The powders were pressed in a uniaxial die and examined with acoustic waves for changes in velocity and attenuation during sintering. The changes in acoustic properties were correlated with sample microstructures and mechanical properties. Evolution of the acoustic echo train during sintering is shown to provide information on the state of sintering as well as having the potential for detection of interior flaws.IntroductionThe versatility of powder metalallurgy (PIM) technology in the manufacture of complex shapes has enabled an increasing amount of wrought and casting production capacity to be converted to PIM technology. However, ultrasonic inspection of green components produced using PIM techniques remains a challenge and is not generally practiced [1]. Inspection of PIM components in the green state is highly desirable, because the green part can be reclaimed with only accepted components being subjected to further costly processing. Another potential benefit is characterization and greater understanding of the sintering process itself. An increased scientific understanding of the sintering process enables intelligent process control, greater reliability of the production process and a lower rate of rejection of the finished product. In order to realize these potential benefits, it is necessary therefore that accept/reject criterion be based on real time nondestructive evaluation of the green-state components and the sintering process.Most current nondestructive inspection techniques suffer from their inability to perform inspections below the near-surface region with the exception of X-ray and to some extent pulsed eddy current [2]. X-ray inspection requires extensive shielding of production personnel and expensive film and film processing. While development of pulsed eddy current techniques have lessened the impact of the well-known skin effect, the depth of penetration of the induced eddy currents remains somewhat of an issue [2]."

Jan 1, 2000

By Joel Anderson

Allvac 718Plus is a newly developed superalloy with a good potential for use in fabricated aircraft engine structures when service temperatures exceed 650°C; the limit for standard alloy 718. Fabrication involves welding, where cracking usually is a prohibitive factor. Comparison of the solidification cracking behavior between these two alloys was made by Transvarestraint testing. It was shown that the total amount of cracking was significantly lower for 718Plus alloy, which was associated with a lower amount of ?/Laves or ?/NbC eutectic-type constituents. This in turn is believed to be due to the lower iron content of the Allvac 718Plus material. The analysis of alloying element segregation both within primary dendrite and interdendritic constituents clearly indicates that the segregation of Nb is the controlling factor in determining the final solidification microstructure in these alloys. The Nb concentrations of these constituents are significantly higher compared to the bulk alloy concentration. This was confirmed by the SEM-EDS analysis and calculations assessed with JMatPro, the latter also indicated that alloy 718 is more prone to form Laves and NbC eutectic-type constituents compared to Allvac 718Plus material.

Jan 1, 2008

By Yi Feng Shi

The ISASMELT process is a submerged lance smelting technology operating in smelters in Australia, the USA, Belgium, India, Germany, Malaysia and China. Further plants are under construction in Peru and Zambia. Initially developed at Mount Isa Mines, Australia, the technology is marketed by Xstrata Technology to companies around the world. Yunnan Copper Co. Ltd. (YCC) commissioned the first copper ISASMELT furnace in China in 2002. The plant quickly ramped up to design capacity and the first campaign lasted more than 2 years. Now into the second campaign, the furnace is exceeding the original design capacity and YCC has won numerous awards for its contribution to reducing emissions and energy consumption. YCC and Xstrata put great effort into managing the design, construction and commissioning of the smelter. Xstrata?s technology was combined with YCC?s novel management approach. This effort has been repaid in terms of the outstanding performance of the plant since startup. This paper updates the reader on the first few years? operation of the YCC ISASMELT plant and discusses the way in which the technology was transferred, leading to fast rampup and, as a result, enhanced profitability for the operators.

Jan 1, 2006

By Etsuro Shibata

For the treatment of huge amounts of the sulfur which is from the earth by both natural and man-made activities, a harmonized sulfur cycle was presented. The man-made sulfur cycle which includes sulfur circulation from oil, coal and ore was analyzed in detail based on the recent world sulfur trend. Then the man-made cycle was compared with the natural sulfur evolution such as volcano. Finally, the harmony in both natural and man-made sulfur cycles was discussed.

Jan 1, 2006

By F. Field, R. Kirchain, J. Gregory

Utilizing alternative materials is an important tactic to improve the environmental performanceof products. Currently a growing array of materials candidates confronts today’s product designer. While life-cycle assessment (LCA) methods provide quantitative input into this selection decision, their implementations are evolving and disparate. The goal of this paper is to explore several major analytical variations of LCA implementations and the implications of these variants across a range of application contexts. Specifically, this paper examines analytical variations in valuation method and treatment of recycling by exploring allocation methods that affect product end-of-life. Case studies across a range of materials are presented, including materials that exhibit a spectrum in variation of environmental performance and material degradation between primary and secondary applications. Preliminary results indicate that the choice of analytical method can have real impacts on individual metrics and there are sets of analytical variation over which strategic results are strongly affected.

Jan 1, 2008

By D. G. Schmidt

Tests were conducted on C86200 high-strength yellow brass in order to ascertain the effect of a low level of nickel on the mechanical properties on this alloy. A series of two alloys was studied, one of which had a nickel content of 0.85% and the other with <0.05% nickel. Copper and aluminum content ranged from 62.5% to 64% and 3.2% to 4.6%, respectively. When compared by zinc equivalents, a nickel addition of 0.75% in high-strength yellow brass does not act like copper but raises the tensile strength, 0.5% yield strength and BHN while lowering the elongation.

Jan 1, 1999

By K. Takahashi, G. Dodbiba, T. Fujita, N. Sato, S. Matsuo, K. Okaya

Different materials are used for manufacturing various parts of a cellular phone. Considering that a great number of mobile phones are being discarded every year, it is important to recover these materials and then recycle them in order to save resources. The primary objective of this work is therefore to find and suggest ways on how to recover various materials from discarded cellular phones for recycling. Much effort, for example, has been put in recovering and recycling tin oxide (ITO), a mixture of indium (III) oxide, (UI2O3) and tin(IV) oxide from the discarded liquid crystal displays (LCDs). Here we report a simple and cost-effective process, which includes a HC1 treatment process for altering the structure of the indium (III) compound into a chlorideinduced indium compound, in order to facilitate the vaporization of indium at a relatively low temperature. The experimental results indicated that 96.2 % of indium can be recovered from ITO, when the sample was heated at 973 K for 90 minutes. In addition, some thermodynamic calculations were also carried out in order to better understand the mechanism for chlorideinduced vaporization of indium.

Jan 1, 2011

By Sundarrajm Suresh, Hrushikesh G. Pimpalgaonkar, Thiyagarajan Paramadayalan

In this paper, a model of a fuel cell system has been proposed to account for the membrane physics at the micro level which is coupled with the macroscopic flow and mass transport phenomena occurring in a single channel of a Polymer Electrode Membrane Fuel Cell (PEMFC) system. We have developed a novel approach to model the catalyst layer electrochemical processes in a Membrane Electrode Assembly (MEA) and coupled it with mass transport and fluid flow calculations at the channel level using STAR-CD commercial software. The predicted values of the cell voltage from this micro-macro model are validated with experimental data available in the literature. A sensitivity analysis has been carried out to study the effect of the design and operating parameters such as catalyst loading and initial temperature on the overall performance of the PEMFC. The results indicate that the cell voltage increases at higher platinum catalyst loading and is also independent of the choice of initial cell temperature.

Jan 1, 2012

By S. J. Kohut

Until recently SX-EW technology has only been used to produce conventional cathode for the cyclical commodity marketplace. Unlike electrorefining, SX-EW lends itself to the integration with the downstream manufacturing technologies for direct mine site production of value added products. The integration of SX-EW and downstream manufacturing results in the elimination of redundant process steps, the cost savings, and the access to value added product markets which can buffer the producer from swings in the cathode market. SX-EW production of copper powder and powder-based products has been demonstrated at the pilot plant level. The SX-EW process has been successfully redesigned to meet the more specific demands of engineered products. Challenges include the solution purity, the cell ventilation, the high current density operation and the product handling. Successful demonstration of mine site production of value added SX- EW products opens up new non-commodity marketplaces to the mining industry.

Jan 1, 1999

By Tanm Engin, Ali Riza Tarakcilar, Derya Dispinar

"Nowadays, the casting industry is developing parallel with the information technologies (IT). Particularly the casting simulation software is being frequently used in foundry floors for casting quality control and optimisation. In this study, the filling and solidification analysis of a rolling roll manufactured by spherical graphite cast iron were carried out by Vulcan casting simulation software. The appropriate defect relieving suggestions were presented by anticipation of defects that may form during the casting process.IntroductionThe optimisation of a casting process has long been the most focused area in manufacturing plants. Many of the work involve not only the process itself but the cost as well. When it comes to the process, it is important to be able to control the defects that may form during casting.The casting process begins with the melting of a charge; followed by pouring into the mould cavity. One of the most important factors is the difference in the liquid/solid density which may lead to porosity. On the other hand, turbulence during filling is another significant factor in casting operations [1].During solidification, due to the density difference between liquid and solid, porosity might form which leads to crack-like defects. There are several other factors that may determine the quality of a casting such as segregation, inclusions, grain size and etc. However, porosity is one of the first parameters that can be easily determine and controlled by the help of simulation software. Simulation is a cost-effective tool in the optimization of process parameters and castings can be visually observed. Time loss and economic expenses could be minimized [2]."

Jan 1, 2012

By J. H. Meza

La Caridad copper smelter is located in the magnificent but rugged Sierra Madre Mountains. This project presents unusual challenges that require the utmost in detailed analysis and planning. The smelter, owned by Mexicana de Cobre, S.A. de C.V., has an annual production capacity of 225,000 metric tons of copper and 600,000 metric tons of sulfuric acid. It utilizes only the Flash Smelting process. This project will expand the annual production capacity to 270,000 metric tons of copper and 1,000,000 metric tons of sulfuric acid. Offgases from the Flash Furnace and the Teniente Converter will be sent to a mixing chamber, from which it will be led to two sulfuric acid plants. This project will then produce a high quality sulfuric acid.

Jan 1, 1995

By P. C. Guillaume

Global plant modernizations or expansions cannot be considered in the same light as any other industrial investment project. Relationships between the partners, relationships and communications with the client, structure and organisation of the teamwork, schedule of the work, and a lot of other tasks and missions devoted to external contractors have to be defined considering one fundamental input: an operating plant. For an engineering company expert in processing, like UM Engineering, such a context requires a specific approach as well as specific procedures able to efficiently challenge the generated constraints. First of all, even if a detailed audit had been conducted at the beginning of the conceptual engineering phase, new elements will be discovered during the preparation and realization of the project, and must be continuously integrated. Consequently, a close proximity to the site is necessary. This is one reason why UM Engineering, most often, works in partnership with a local engineering company. The second important point for the client is that the operation must not be interrupted during the realization. In order to make that possible, UM Engineering has defined a specific project structure and organisation, integrating on a permanent basis the operators (the "users") in the project teams. This paper presents the way UM Engineering copes with this type of "multi-constraints" context with reference to the recent copper cellhouse modernization under realization for the CCR Refinery of Noranda Inc. in Canada.

Jan 1, 1999

By Antonio de Ita, Isaias Hilerio, Miguel Barron

"The influence of an unconventional lance with a central nozzle on the multiphase fluid flow in a steelmaking converter is studied in this work by means of computer simulations. The lance has four peripheral supersonic nozzles and a vertical central nozzle. Besides, the oxygen flow in the central nozzle is considered independent from the main oxygen supply. Transient two-dimensional numerical simulations were carried out considering just molten steel and gaseous oxygen as the existing phases. Numerical results show that bath agitation and droplet generation are enhanced as a result of the central nozzle. However, the performance of this lance strongly depends on the distance of the lance tip to the molten steel surface and the velocity of the oxygen jet.IntroductionCurrently, two thirds of the world crude steel is produced through the steelmaking oxygen converter [1]. Given the unquestionable economic importance of this technology, any improvement or optimization proposal is welcome. In the majority of current oxygen converters a top oxygen supersonic jet is blown onto the molten steel through a water-cooled lance to eliminate by oxidation some impurities such as carbon and phosphorus. Conventional lances have inclined peripheral nozzles whose number depends on the converter capacity. During the process, a large amount of gases evolves, forming metal droplets and a metal-slag-gas emulsion [2]. The droplets and the resultant emulsion increase the reaction interfacial area, promoting in this way carbon removal and dephosphorization of the molten steel bath [3]. However, during the blowing stage, the emulsion rises towards the lance and converter mouth and frequently forms layers which accumulate in the lance, reducing the life of the lance tip [4, 5]. It is possible that some freezing of the molten metal occurs due to the low oxygen injection temperature, however there are no reports on this. Besides, frequently undesirable operating phenomena such as spitting and slopping may arise as a result of inappropriate blowing practices or bad lance design. In the oxygen steelmaking industry, novel lances design are needed in order to enhance the decaburization rate and the slag formation and, at the same time, preventing operating practices that decrease productivity and move away the shop from safety standards."

Jan 1, 2012

By Thomas Schuman, Jaan Kers, Lucas N. W. Damoah, Xiangjun Zuo, Lifeng Zhang

"Rapid technological innovation has propelled the use of electronic equipment leading to the generation of more and more waste electrical and electronic equipments (WEEE). Printed wiring board (PWB) is a component made of one or more layers of insulating material with electrical conductors. To investigate an environmentally friendly process to recycle PWBs, PWB samples with and without additives were pyrolyzed. Liquid, gas and solid products were achieved with different conversion fraction. Analysis of the exhaust gases from the experiments using GC-MS and MS showed that without CaCO3 additives poisonous gases such as C6H6 and HBr were produced which were adequately controlled if CaCO3 was added.IntroductionPyrolysis is one of the best methods for treating complex mixtures of waste polymers and to recover the material and energy content. The process consists of thermal decomposition at moderate temperatures in total absence or small amount of oxygen in which the structures of polymers break down into smaller intermediate products "". The decomposition temperature of a substance is the temperature at which the substance breaks up into smaller substances or into its constituent atoms 2). Thermal treatment of PWBs were reported using DC Arc Plasma furnace 3), and fixed bed reactor 4). One drawback in dealing with thermal treatment of PWB scraps is the likely production of super-toxic halogenated dibenzodioxins and dibenzofurans from the bromine containing structures. Pyrolysis of organic materials contained in waste PWBs leads to the formation of gases, oils, and chars which can be used as chemical feedstock or fuels ""'. Dehalogenation of the pyrolysis product of electronic scraps is essential to make it commercially acceptable. It would be obviously the most advantageous solution as pyrolysis and dehalogenation are carried out simultaneously. Reported pyrolysis investigations are at experimental stage and have been carried out in vacuum, molten salt, fluidized bed, rotary kiln, entrained, stationary, and moving bed reactors 7). Comparing to the incineration and combustion of PWBs, the pyrolysis process has several characteristics: 8'"">) 1). Converting the organic solid substance into fuel gas, fuel oil and carbon-black as storage energy; 2) Emitting toxic substances such as sulfur, bromine and heavy metals in wastes; and 3) Keeping metals from being oxidized. Although many researches into the pyrolysis of PWB wastes have been reported, most of the works have been carried out using analytical pyrolysis techniques or very small batch reactors ""~'5). Also, most of the works for the pyrolysis of PWBs haves concentrated on the composition of the organic products, particularly the brominated organics. The current study is to investigate the pyrolysis of PWB powders in a small TG-DTA scale and a 50-gram tube furnace scale."

Jan 1, 2011

By Michael Meyer

In the past shredder fluff was discarded in landfills, but shrinking landfill space and the partly hazardous content of the fluff as well as its caloric value, all resulted in efforts to turn this waste problem into a an energy resource. In order to produce a fuel, the inorganic compounds have to be removed. Extensive analyses and particle size measurements were made on fluff from various shredder. For optimal separation all particles are reduced to a uniform, relatively small size. In a subsequent combined - screening and air classification - process, successful separation into organic and inorganic fractions is achieved. The inorganic fraction is treated in a heavy media or an eddy-current separator to recover the valuable metals, while the organic fraction is now suitable for thermal processing, such as fluidized bed gasification and using the resulting carbon as a chemical reagent.

Jan 1, 1995

By N. J. Rarmrez, C. Perez, J. D. Calderon, L. Lopez

"Among the thermal characterization of any material, one of the variables to know is the coefficient of thermal conductivity because this value can tell how much heat passes through the material and if the material could be used as an isolator. In order to determine this parameter is required some kind of special equipment and controlled conditions which implies high costs in the development of tests. The present paper proposes a design of a low cost measurement system in order to determine this coefficient with the lower possible error. This equipment was thought for companies or labs where they do not have the economic resources or the infrastructure (environmental controlled labs, heat flux transducers, human resources with specialized knowledge) to do this kind of tests.The system is based on ASTM C 518 - 04 [l] and integrated by two plates (one that contains a thermal resistance and which temperature is controlled by a closed loop controller and the other one with a route of water flow). The thermal resistance is actuated by a relay and a supervisor system checks the total time the relay is on in order to determine the effective power applied to the system. The contact faces of the plates contain a group of temperature sensors connected to a data acquisition system that process and record the temperature in each measurement point.With the power applied to the system, the measurement of temperatures and a process of calibration is possible to determine the coefficient of thermal conductivity. IntroductionWithin the thermal characterization of a material of known variables is the coefficient of heat transfer, since this value can know the amount of heat the material is capable of transferring or isolating. To determine this ratio requires specialized equipment and controlled conditions, which implies high costs in the development of a test. This article proposes a design of a low cost machine to allow closer this coefficient with the least possible error. This equipment was done thinking about companies that do not have the infrastructure (laboratories, controlled environment, heat flux sensors, human resources expertise) and financial resources to conduct these tests."

Jan 1, 2011

By W. G. Davenport

Most pre-t 988 Outokumpu flash furnaces were built with blast heaters. Many continue to use them. Blast temperatures in these smelters· are typically 400 to 700 K (Table 2. 1) This chapter: (a) shows how hot blast is included in our calculations (b) evaluates the effects orhot blast onauthothermal65% Cu matte production.

Jan 1, 2001

By Na Wang, Chao Du, Hongmin Zhu, Kai Huang, Shuqiang Jiao

"Niobium aluminides were directly synthesized by a sodiothermic reduction process of NbC15 - AlCb which was dispersed into LiCl - KCl - NaCl - CaCb melts. The melt supplied a homogenous reaction medium which was substantially beneficial to the co-reduction of Nb and Al to form niobium aluminides in situ. The reduction was performed at 500°C for 4 hours. The products were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The corresponding results indicated that niobium aluminides powders were successfully synthesized.1. IntroductionNiobium aluminides have received considerable attention as high-temperature structural materials, due to their high melting points, relatively low density, high strength, excellent oxidation and creep resistance [1-4]. Figure 1 shows that there are three intermetallic compounds in the Nb - Al binary [5], which includes Nb3Al (A15 structure, Cr3Si type), Nb2Al (D8b structure, cr-CrFe type) and NbAb (D022 structure, TiAb type). These niobium aluminides have been used in turbine blades or in stationary gas turbines [6-8]. However, despite their attractive features, the ir applications are still limited by the long and costly fabrication process [9, 10].Niobium aluminides were industrially fabricated by the mechanically alloyed process [11-13]. Traditionally, niobium is extracted from Nb2O 5 or K2NbF7 by a metallothermic reduction process while aluminum is produced by the Hall-Heroult process of Ah03 electrolysis. Based on the extraction of Nb and Al, respectively, niobium aluminides is synthesized by a mechanical powder alloying process. The present process for making niobium aluminides requires a set of complicated equipment, has high production cost and time consuming [14, 15].The purpose of this work is to present the simple, economic and direct synthesis of niobium aluminides powders utilizing a sodiothermic reduction from NbC15 - Al Cb dispersed into molten salts."

Jan 1, 2011

By Pedro A. Netto, Sergio N. Monteiro, Foluke S. de Assis, Rômulo L. Loiola, Frederico M. Margem

Banana fibers are among the lignocellulosic with great potential for use in polymer composites, such as the variety from the Musaceae family, due to its low density and good mechanical properties. In this work, epoxy matrix composites incorporated with continuous and aligned banana fibers were tested for their flexural behavior. Specimens with up to 30% in volume of fibers were bend-tested until rupture. The results showed an increase in both the composite mechanical strength and the stiffness with incorporation of these fibers. A fractographic analysis by SEM examinations a moderate adhesion mechanism between the banana fiber and the epoxy matrix. This mechanism is apparently responsible for the improved performance of the composites.

Jan 1, 2015

By Guangchun Yao, Chuan Li, Hongjie Luo, Zhuokun Cao

"The expansion rate and collapse time of liquid aluminum foams are essential for the determination of operating time and quality of the resulting foam. In the present paper, liquid aluminum foams was fabricated by adding in TiH2 as blowing agent, and the variation of expansion rate with foaming time was non-contact detected by a laser distance measurer. The influence of different stabilizing agent and alloying elements was studied. The results show the fact that the fraction of stabilizing agent only perform little effects on the maximum expansion rate of liquid aluminum foams, while the influence of alloy elements are remarkable. The maximum expansion rate would increase much when Mg is added, and the liquid foam also collapse at a shorter time. Comparison was made between experimental results and mathematic calculations, which reveal the fact that it is the change of TiH2 decomposition responsible for the change.IntroductionMetal foams, combining light weight with other unique mechanical and physical properties, have gained wide interest and been developing fast during past few decades. However, manufacture of this new material is quite challenging since it involves simultaneous occurrence of gas, liquid and solid phase at high temperature [1-2].Quite some manufacture routes have been developed for manufacturing metal foams, and the structure and quality of resulting foam are remarkably improved during the last decades. However, most of the past works seems to be experiential, and because the lack of basic knowledge of foaming process, the start material is limited and the production technologies are far from reliable and reproducible.[3-4]In direct foaming process, decomposition of blowing agents, TiH2 for example, is the main force for foam expansion. The density and foam structure changes with time during the foaming process, so it is expected that foams of certain structure can be obtained by solidification of the liquid foam at a certain time [5-6]. However, the foaming process is weak in reproducibility and the influence of stabilization additives and alloying elements is unclear."

Jan 1, 2011