Search Documents

By K. Kashiwaya, N. Hiroyoshi, H. Furuya, N. Sumiya, M. Tsunekawa, M. Ito

"The number of hybrid vehicles is increasing and this is causeing an increase in waste nickelmetal hydride batteries. The cathode activating agent of batteries is made of nickel hydroxide and the anode activating agent is an alloy of nickel and rare earth elements. Conventional rotary kiln methods cannot recover the rare earth elements, and hydrometallurgical treatment of crushed product consumes large volumes of agent. The physical separation of the anode alloy from the cathode hydroxide would make it possible to reuse the alloy. The authors have reported separation of anode and cathode components in the large size fractions using a newly developed dry magnetic separation method. Wet magnetic separation has been applied to the powder fraction and about 90% anode purity was achieved. This paper reviews experimental results from previous publications and proposes an integrated treatment process for crushed nickel-metal hydride batteries.IntroductionEnvironmentally-conscious clean energy vehicles have attracted much attention in developed countries and particularly hybrid vehicles are increasingly mass-produced as low emission vehicles. Hybrid vehicles have both a gasoline engine and an electric motor to save on gasoline usage and a nickel-metal hydride battery is used to store electric energy. The battery contains Nihydroxide and Co as the cathode activating agent and an alloy of Ni and mischmetal (mM), a rare-earth element mixture consisting of La, Ce, and Nd, as the anode hydrogen adsorption component. In conventional recycling, the Ni and Fe are recovered with a rotary kiln-electric melting process and the Co and mM go to the slag component [1] and hydrometallurgical treatment of crushed product consumes large volumes of agent. Japan Oil, Gas and Metals National Corporation have proposed a low energy and low cost recycling treatment process combining the physical and chemical treatments and the authors are investigating the physical treatment process."

Jan 1, 2008

By Uchil Jayagopal, P. V. Krupakara, S. Manjunath

"This paper deals with the corrosion characterization of quartz particlate ZA-27 alloy metal matrix composites (MMCs). Quartz particles of size 50-80 microns are used as reinforcement. MMC's are prepared according to ASTM standards. Composites containing. 2, 4, and -6% by weight of quartz and unreinforced matrix were tested using 1 -N hydrochloric acid: The composite was found to be more corrosive resistant than matrix alloy. In each test the corrosion resistance of both alloy and composites were found to decrease with the exposure time.1. IntroductionMetal matrix composites- (MMCs) offer designers many added benefits, as they are particularly suited for applications requiring good strength at high temperature, good structural rigidity, dimensional stability, and light weight 1-5. The trend is towards safe usage of the MMC parts in the automobile engine, which work particularly at high temperature and pressure environments Particles reinforced MMCs has been the most popular over the last two decades.ZA alloy MMCs have most popular families being represented by. ZA-27 alloy reinforced with ceramic particulate. Although the incorporation of the second phase into a matrix material can enhance the physical and mechanical properties of the base metal, it could also significantly change the corrosion behavior.ZA alloys have been used extensively in industry. This is attributed to their excellent fludity, castability and good mechanical properties. Among the zinc-based foundry alloys, the ZA family of alloy have been widely used during the past few years. ZA alloys have many advantage over aluminium based ones, especially high strength with a low casting temperature 8."

Jan 1, 2000

By Hebi Yin

A two-dimensional finite element solidification model was developed to simulate the transport phenomena occurring during laser deposition of AISI 410 stainless steel during the Laser Engineered Net Shaping (LENS®) process. The molten pool geometry and the distribution of temperature, solute concentration and velocity were calculated during deposition of a thin wall plate. An analysis of the simulations results revealed the importance of heat transfer by both conduction and convection as well as the roles of the driving forces for convection in the molten pool. The heat transfer and the flow pattern in the molten pool are considerably dependent on the travel speed of the laser beam. For the alloy and process parameters in the simulations, no significant macrosegregation was observed. The temperature-dependent properties and thermodynamic variables involved in solidification modeling were calculated using Thermo-Calc software. The results of this work contribute to the current understanding of transport phenomena in the molten pool of laser deposition processes.

Jan 1, 2008

By Susan A. Fredholm, Randolph E. Kirchain, Elsa A. Olivetti, Jeremy R. Gregory, Jeffrey B. Dahmus

"A general model for evaluating the economic and environmental performance of electronics recycling systems is developed. This model comprehends the three main functions in a recycling system – collection, processing, and system management – and aims to enable quantification of the impact of context and system architecture on the economic and environmental performance of electronics recycling systems. Such a model can be used both to evaluate and improve existing electronics recycling systems, as well as to design and implement new systems. A case study, based loosely on Maine, is presented to show the utility of such a model.IntroductionAs recycling systems for complex durable goods (CDGs), and in particular for waste electronics, become more widespread, understanding the economic and environmental performance of such systems becomes critical, both to enable improvement of existing systems and to inform the design of new systems. However, with the range of possible system architectures and the important role of locational characteristics (context), understanding the determinants of system performance is challenging [1]. To address this issue, a modeling framework to project the economic and environmental performance of CDG recycling systems, based on contextual and architectural characteristics, has been developed.The modeling framework presented here comprehends the three main functions – collection, processing, and system management – which are common to most recycling systems. These three functions are modeled using a variety of modeling techniques and serve as a bridge between inputs related to system context and system architecture, and outputs related to economic and environmental performance. The models developed here are intentionally meant to be both broad, in order to address entire recycling systems, and general, such that many different systems, both real and hypothetical, can be analyzed."

Jan 1, 2008

By Rivera Jose Antonio Ore

Top Submerged Lance (TSL) smelting technology is currently used in a wide range of applications in the non ferrous and waste product treatment industries. The use of TSL technology for tin concentrates smelting has been successfully applied at the Minsur Tin Smelter and Refinery at Pisco, Perú. The process is based on the air-cooled top entry submerged Sirosmelt lance, developed by Dr. John Floyd at the CSIRO division of Mineral and Process Engineering in the 1970?s. Advantages of the process include flexibility to operate the lance, main burner of the Sirosmelt furnace, with different levels of combustion stoichiometry which allows us to get from highly reducing to highly oxydising atmospheres in the smelting reactor according to the type of feed we are processing, ability to utilize cheap energy sources such as natural gas, low capital cost and an environmentally friendly operation. This presentation summarises the application of the Submerged Sirosmelt technology for smelting tin concentrates and a variety of tin containing materials like iron dross, copper dross, tin residues, low tin/antimony slags by applying recent metallurgical developments at the Minsur smelter. The impact of new feed conditions and level of impurities on reactor performance with features of process and operation control are described. As a result of these recent advances in tin smelting using TSL technology, the Minsur Tin Smelter and Refinery improved its overall tin recovery, substantially reduced tin inventories and became the second largest tin smelter in the world, currently producing more than 40,000 metric tones of refined tin per year.

Jan 1, 2006

By V. I. Lakshmanan

"Historically flowsheets are developed for efficient separation of metals for economic recovery. With increasing emphasis on reduction, reuse and recycle (3Rs) efficient methods are sought to recover values from a variety of feeds where cost of collection, transportation, local consumer behaviour and regulatory guidelines dictate the development of economically viable flowsheets. Innovative understanding of potential market applications can provide means to develop value added end products. The paper with examples will discuss the use of innovative-separation technologies to obtain value added end use materials from secondary sources.IntroductionFlowsheets are developed for the efficient separation of materials of value for economic recovery. However with increasing societal pressures and regulatory initiatives for stricter environmental guidelines, there is strong need to provide focus to recover materials efficiently and economically in an environmentally accepted manner. North American industries are increasingly caught between demands for high technology value added products and responsibility for environment. An aspect that is receiving increasing attention is Design for Environment'. This incorporates a system wide approach for product design and incorporates environmentally preferable features such as recyclability, disassembly, maintainability, reusability and use of safe materials as part of a product's design objectives.The present paper with case histories will address innovative flowsheet development to convert wastes into recyclables value added products or for minimising generation of waste materials. Case HistoriesProcess for Separating Fibres from Composite Materials 1In the automotive industry, sheet molded compound (SMC) is used to produce panels, bumpers and the like. During the manufacture and at the end of life, considerable waste materials are generated which are potentially recyclable. Fibre reinforced plastics where fibre substrate impregnated with thermosetting resin, find applications in several manufacturing processes and are potentially recyclable at the end of life."

Jan 1, 1996

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 Gjergj Dodbiba, Atsushi Shibayama, Toyohisa Fujita, Takashi Shikazumi, Yukio Kato, Kenji Murata

"A new crushing or liberation technique by means of underwater explosion is put forward. This technique is suitable for crushing and liberating various materials, for instance: the electric parts of the discarded portable telephone, CPU from mother-boards of PCs, steel from plastics tubes used as construction materials, waste constructed materials like panels, tungsten carbide scraps, as well as slitting the optical disk (e.g. DVDs), etc. The materials to be crushed are immersed in water and then the explosion is carried out by using only a small amount of explosive. The shock waves in combination with the generated bubbles are very effective in liberating the materials of different densities. It was observed that the metals crushed or liberated by using this technique were leached much faster when compared with the conventional crushing technique. This crushing method can be applied for liberation of many kinds of electric or mechanical tools. Introduction The explosive has been used since Nobel’s invention in 1866. The main practical application of explosion is in the large scale public works, such as dam construction, land development, tunnel, mining and dismantlement of building. The shock wave caused by explosion extremely can generate high pressure able to break the concrete and rock, and other materials. In this study, the crushing and liberation of waste materials was carried out by explosion in water. The idea was to use this technique as a pretreatment stage prior to recycling. The explosion in water can be used to crush hard materials, helping the liberation between different attached materials. The samples used in this experimental work are waste materials such as construction materials, hose, cemented carbide, cellular phone, lithium buttery, DVD-R, etc."

Jan 1, 2008

By O. M. G. Newman

Research into potential applications of spouted bed electrowinning (SBE) in the zinc industry was conducted, in a collaboration between our two organizations. The main system investigated was zinc from acidic sulfate electrolytes. However, SBE can be extended to other electrolytes, or recovery of other elements. Electrolytic tests were carried out at the 0.01 to 0.1 m2 scale. Spouting behaviour has been studied at a larger scale, approaching a size suitable for an industrial unit cell. Much of our work was carried out using a micro-porous separator (Daramic®). However, we have also shown that ion exchange properties can have a controlling effect on the process chemistry, electrochemical efficiency, and plant flowsheet. In initial 0.1 m2 scale electrolytic tests, design and engineering issues for scale-up were identified. We review the major achievements, promising areas for application in the zinc industry, current status, and remaining barriers to development of SBE technology.

Jan 1, 2003

By Dongok Kim

Regardless of the advantages of the Friction Stir Process (FSP), for age-hardened aluminum alloys, the mechanical properties such as hardness in the stir zone decreased after FSP due to the growth or dissolution of strengthening precipitates. Here, as a new technique, FSP was introduced to alloy copper nanopowders in Al7075 T651. Mechanical properties of copper nanopowder- alloyed Al7075 T651 together with micro and nanostructures were compared with those of as-FSPed Al7075 T651 using SEM, TEM, and Vickers hardness testing to understand structure-property relationships. It was observed that Vickers hardness of the stir zone in copper nanopowder alloyed Al7075 T651 increased by 20% compared to that of the heat affected zone, while the as-FSPed samples did not show a noticeable increase in hardness in the same zone. Xray mapping showed traces of copper nanopowder after the process. TEM is being used to verify if there was CuAl2 formed in the copper alloyed sample.

Jan 1, 2006

By Yinlun Huang, Cristina Piluso

"Industrial sustainability looks to improve material and energy efficiencies, product quality and variety, and productivity within an industrial zone, thus pursuing the long-term sustainable development of the region. This paper introduces a systems-based modeling methodology, which provides industrial leaders with the ability to evaluate future production options to determine the path with the highest positive impact on both their own sustainability and the sustainability of the overall industrial zone. A comprehensive study on sustainable development of an auto-manufacturing focused industrial zone under uncertainty is illustrated. Introduction Sustainable development refers to a continuous process of improvements that must be followed in order to achieve a state of sustainability. In its most general form, a widely accepted definition of sustainable development was identified in the Brundtland Report as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” [1]. Sustainability will occur when the material and social conditions can be maintained or improved for human health and the environment over time without exceeding the ecological capabilities that support them [2]. An industrial zone is defined as a geographic area comprised of a network of industrial sectors, each composed of a number of entities. Such a zone is highly integrated and complex, and contains numerous uncertainties due to each industry’s extreme dependencies on its suppliers and customers throughout the product supply chain. In the context of an industrial zone, sustainable development refers to the continuous process of advancements in the zone, and the entities that comprise it, creating more value, wealth, and profits (economically viable dimension), providing environmentally benign products with less raw material consumption and waste generation (environmentally compatible dimension), and collaboration and a direct relationship among all involved in the supply chain, i.e. the corporations, employees, suppliers, investors, communities, customers, etc. (socially responsible dimension). These are the triple bottom lines of industrial sustainability. In order for economic, environmental, and social sustainability improvements to be successfully implemented within an industrial zone, the industrial decision makers must possess system-wide analysis abilities. The analysis of the sustainable development of an industrial zone involves decisions at the local, regional, or national levels, which are complex and involves handling of ill-defined parameters with a high degree of uncertainty due to the imperfect understanding of the underlying issues [3]. This work focuses strictly on the uncertainties in future zone planning and a method and a scenario based approach that can be used to evaluate the sustainable development of an industrial zone among these uncertainties."

Jan 1, 2008

By A. W. Bryson, K. C. Lenthall

"With the growth in the use of cobalt in industry, interest in its extraction and recovery has increased. With this increased interest comes the need for a fundamental knowledge of the processes involved in the recovery of cobalt metal. This paper examines the effects of cobalt concentration, catholyte pH, operating temperature and current density on cobalt electrowinning with respect to the current efficiency, cell potential and nature of the cobalt deposit. It is found that the cobalt concentration and catholyte pH affect the current efficiency, while current density and temperature affect the cell potential and thus the specific power consumption. Pitting on the deposit is affected by the catholyte pH and the operating temperature. Furthermore, the effect of feed flow-rate on catholyte pH, and thus current efficiency, is investigated. A model to predict the cell performance, which includes the flux of hydrogen ions through the diaphragm, is proposed.IntroductionCobalt metal is a silvery transitional metal found between nickel and iron on the periodic table. Due to its resistance to corrosion and other properties under high temperatures and its good work-hardening characteristics, it is favoured in alloys used in high temperature applications. These include aerospace, aircraft and high speed tools. Other applications include its use as a colourant in glass and ceramics, a drying agent in paints, a nutrient for livestock, a catalyst in the petroleum industry and, in the medical field, in prosthetics and radiology.The main deposits of cobalt are found in Central Africa, specifically Zaire and Zambia, although deposits also occur in Morocco, Canada and Australia. The cobalt is generally associated with other transitional metals including nickel, iron and copper. It is generally extracted by hydrometallurgical means and recovered from solution by electrowinning or hydrogen reduction. Little data [1-2] exists in literature on the electrowinning of cobalt from aqueous solutions. This paper investigates the effects of various operating conditions on the current efficiency, cell potential and deposit nature under continuous operation."

Jan 1, 1997

By Aline Maria dos Santos Teixeira

Serpentinite is an ultra basic and metamorphic rock consisting mainly of magnesium, calcium and silicon oxides. The rock under study is a host rock of chromite mine located in Andorinha, BA. The objective of this paper is to evaluate the rock's physical and chemical characteristics to be used as an additional fertilizer of acid soils. After comminution, rock samples were submitted to chemical analysis, XRD, SEM-EDS and TGA. Afterwards, particle size distribution was determined. Result analysis confirms that our rock consists mainly of dolomite, calcite and diopside. According to the result obtained, it can be said that the serpentinite rock has promising applications in agriculture for the correction and additional fertilization of acid soils. However, it is necessary to study the characteristics of the rock such as its dangers and toxicity as well as evaluate them according to the legislation for corrective acidity.

Jan 1, 2010

By Igor Zh. Bunin

A model for developing electric discharges between sulfide mineral (pyrite) particles under high-voltage nanosecond pulses in a liquid medium (water) is considered. A possibility of electrical breakdowns of liquid gaps between particles under nanosecond pulses is shown. This probability and the energy released in discharge channels depend strongly on the sulfide conductivity.

Jan 1, 2010

By Clara María Lamus Molina

The following minerals found in the residual black sands from gold mining in El Bagre Antioquia (Colombia) were identified as having major economic interest: Ilmenite (FeTiO3), with an average of 49% of TiO2, frequently altered presenting crowns; lamellaes of rutile and alteration textures; titanomagnetite with up to 25% of TiO2; magnetite (Fe3O4) in individual grains or associated with others minerals as hematite and ferromagnesian silicates rutile (TiO2) with considerable quantities of Nb2O5(0.1-3.7%Wt); zircon (ZrSiO4) with 66%Wt of ZrO2 and monazite with an average of 63.43%Wt of REE, this frequently associated to xenotime and thorite forming textures as little drops. Analysis in EPMA and SEM/EDS showed percentages of minor elements and traces, thereby clearly establishing the applications of these minerals in diverse industries. Furthermore, a detailed granumetric study of the different minerals and textural relationships among them also allowed for establishing the basis for possible processing and exploitation.

Jan 1, 2006

By Tammy G. R. Portela

A comparative characterization of the dimensional and mechanical properties as well as structural aspects of two different types of fibers extracted from the leaves and petioles of the buriti palm tree was performed. A statistical analysis revealed that both types of fibers present a significant dispersion in length and equivalent diameter. However, the corresponding intervals of dimensional variation are sensibly different. The tensile properties showed that both types of fibers display a tendency of higher strength for smaller diameters. Moreover, the fibers extracted from the leaves depict a comparatively lower strength. By contrast, the fibers from the petiole present an average strength sufficiently high for the use as reinforcement of polymeric composites. The structural aspects of tensile-rupture fibers, characterized by scanning electron microscopy, showed marked distinction in the microstructure and fiber behavior of both types of investigated fibers. This could explain the differences in mechanical behavior

Jan 1, 2010

By S. Y. Tan

The thermal stability of fully silicided NiSi with arsenic doping on silicon was investigated. The aims of the work were to investigate the Ni silicide phase-related issues associated with arsenic dopant and thermal annealing on Ni-FUSI/HfO2/Si and Ni-FUSI/HfSiO/Si gate stacks. It was found that arsenic-incorporation demonstrated some improvement in both morphology and phase stability of nickel silicided films at high processing temperatures regardless underlying gate dielectrics. The correlations of Ni-Si phase transformation and arsenic doapnt with their electrical and physical changes were established by sheet resistance measurements, X-ray diffraction (XRD), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) analysis. Furthermore, the modulation of the work function (WF) of Ni fully silicided gates by arsenic impurity is presented, comparing the effects of dopant (As) on the WF and silicide phases (NiSi and NiSi2). It confirmed that the work function of NiSi can be tuned by implanting arsenic dopant, but it ineffective for NiSi2 phase.

Jan 1, 2010

By Sang-Joon Kim, Hae-Geon Lee, Hyun-Jin Cho

"Decarburization phenomena on the surface of liquid iron have been simulated by numerical method and the results were compared to the experimental data. During the DeC process in a converter, a large amount of splashed droplets are generated from the top surface of the bath and consequently the reaction surface area is increasing tremendously. Since the decarburization mainly occurs at the interface, it is important to understand the reactions on the liquid iron droplets. The flow and species concentration fields around liquid droplets taking into account the reaction of carbon with oxygen at the interface were calculated by a commercial CFD code FLUENT which solving multiphase Navier-Stokes equation with Volume Of Fluid method, species transport equations and energy transport equation. The initial carbon concentration was fixed to 4 wt% and the concentrations of oxygen in the atmosphere were varied from 5 to 50 wt%. As comparing the numerical calculation with experimental data written in the reference, the results have a good agreement for decarburization rate.IntroductionIn a primary steelmaking process, one of the main functions is to decarburize from hot metal and the 4% of carbon is decreased to about 0.5% of carbon. Even though there are some possible reactions leading to the removal of carbon from hot metal, the main reaction occurs on the free surface by direct oxidation of carbon at the gas-liquid interface with producing the carbon monoxide gas. In many metallurgical processes involving a jet impinging onto a steel bath surface, especially in a Basic Oxygen Furnace (BOF) converter, it is important to understand the behavior of molten iron droplets splashing out of the steel. The iron droplets are generated by an oxygen or air jet blowing and it increases the total surface area of liquid iron tremendously. Since the decarburization reaction is mainly affected by the surface area, it is necessary to verify the decarburization phenomena around the splashed droplets from liquid iron in order to allow an analysis ofBOF process possible."

Jan 1, 2011

By Xiao Caimei

The method of Substance Flow Analysis (SFA) provides a helpful tool for the study of the industrial metabolism of a certain metal within a regional level, such as copper, lead etc. In this paper the flows and inventory of cobalt in China, 2008, were traced with the STAF model, and the situations of production, fabrication and manufacturing, use and waste management in China were introduced. The result revealed that the resource of cobalt in China was so poor that a large amount of cobalt material or cobalt products needed to be imported, and there was lack of recycling of cobalt resources.0

Jan 1, 2010

By Markus A. Reuter, Antoinette van Schaik

"Product design engineers select from a wide range of materials and combine them into multimaterial product designs. These include various materials (metals and non-metals) which are complexly integrated (e.g. welded, glued, alloyed, layered). The recycling/recovery rate of consumer products are determined by the different materials and alloys used, but also by the particle size and multi-material particle composition after shredding (combination of materials due to design). Eco-design (for recycling) and Design for Recycling (DfR) can only be conducted if the interconnectivity of material/metal in various unliberated materials is accounted for and its effect on material and energy recovery can be linked back to design. This paper will discuss the basic principles of these DfR models and it is shown how these tools (i) are linked Computer Aided Design (CAD) and Life Cycle Assessment (LCA) software, (ii) affect conceptual design specifications of products, (iii) integrate the complex detail of the recycling system and recyclate quality and hence (iv) make recycling an integrated part of the product system. Furthermore, it is shown how these assessment tools and models can be applied for benchmarking of the recyclability and environmental damage created by the recycling of end-oflife consumer goods in order to e.g. (i) provide the (original) equipment manufacturer with knowledge and solutions to support product stewardship and Extended Producer Responsibility; (ii) create awareness of the consequences/benefits of design, products and recycling systems to manufacturer, designer, legislator, recycler etc.; and (iii) assist the consumer in their choice of consumer goods from an end-of-life point of view.IntroductionA first-principles basis is required in order to be able to simulate and predict the recycling/recovery behaviour of products facilitating Design for Recycling (DfR) and Eco- Design. This links recycling technology and the environmental consequences of recycling directly to product design."

Jan 1, 2008