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By Mahmoud A. Rabah

"In this work, metal values were prepared from used beverage cans. The cans are made of aluminum and minor alloying metals and printed with a multi-color printing ink. A method has been investigated to remove the printed coating using organic solvents or by sand blasting technique in a rotating drum. Metal values of the cleaned cans are prepared applying combined hydro and pyrometallurgical treatments. Factors affecting the efficiency of the suggested method have been studied.The results show that the extent of removal of the printing coating is successfully performed with recyclable methyl ethyl ketone I dimethyl formarnide mixture. With sand blasting, it proceeds regularly with the inner diameter, the rotation speed of the drum, the size of the sand grains and temperature. The removed coating is stripped with the same solvent. Metal alloy(s) are prepared in two ways. In the first way, the cans are pressed into solid blocks using hydraulic press before melting at temperatures up to 1000°C using borax-sodium chloride salt mixture as a flux. The quality of the metal obtained is a function of the salt and temperature. The slag so formed was leached with mineral acid solutions. In the second way, the used beverage cans are directly dissolved in mineral acids whereby different metal values are selectively precipitated. The undissolved part is fused with sodium carbonate at 800°C and processed in the same manner. Results were explained in the light of the thermodynamic properties of the species involved."

Jan 1, 2000

By Juliana G. Gutierrez-Paredes, Gabriel Plascencia-Barrera, Fidel Reyes-Carmona

In Mexico, many tonnes of nickel from waste petrochemical catalysts are dumped every year. In order to recover all that nickel, a hydrometallurgical reactor was designed. This design was performed in a systematical fashion, which included the chemistry of the system under study, both a kinetic and mass transfer study, and finally the use of the RID function, to optimize the reactor size. It was found that the NiO leaching with sulfuric acid is well represented by a first order reaction. The mass transfer results are in good agreement with the experimental results, obtaining over 95% nickel extraction in both cases. A marketing study was also completed that determined that it is possible to make a good profit by processing this residue provided the capital cost was low.

Jan 1, 2000

By Ahmadzadegan. Arash, Anil Saigal, Michael A. Zimmerman

"In this study, the rheology of liquid crystalline polymer (LCP) melts through simplified 2-D and 3-D die geometries is simulated using Polyflow™. It is known that rheological properties of LCPs are close to long chain polymers and their directionality is close to those of small molecule liquid crystals (SMLCs). As a result, different rheological models (both viscoelastic and generalized Newtonian) for long chain polymers in Polyflow™ were investigated based on the available capillary rheometer data. By varying the parameters in these models, it is possible to adjust the effect of shear viscosity, normal stress differences and relaxations times on the rheology of the polymer. The free surface of the extrudate coming out of the die is simulated and the amount of die swell for different types of rheological models is compared. This study indicates that the Bird-Carreau model best applies to thermotropic LCP materials as quantified by die swell. Since the rheology of the LCPs affects the orientation of the crystals, the result of this simulation can be further used to predict the orientation of crystallines inside and outside the die.IntroductionAny rod like molecule or crystal tends to orient itself in the direction of shear as it moves within a flow. Since polymers consist of long chains of molecules, they experience the same phenomena when flowing in the melt condition. For most polymers, the molecules change direction and distribute uniformly in space during the solidification. However due to the higher inertia of the crystals in the liquid crystalline polymers, the oriented crystals will keep their order during the solidification and as a result the final product will show anisotropy in material properties."

Jan 1, 2012

By Adam Gesing, Ron Dalton, Richard Wolanski, Larry Berry, Christopher Stewart

As the quantity of aluminum recovered from shredder scrap continues to increase, together with increased content of aluminum in automobiles, so does the economic incentive to further upgrade shredder scrap. This upgrade will be done by sorting and recovering the aluminum by specific usable alloy compositions. The metal recycling industry infrastructure needed to deal with the increased aluminum scrap supply already exists. It is an inverted pyramid structure that in North America comprises: 3000 scrap collection yards, 200 shredders, a dozen sink-float plants and one heavy metal sorting operation. The technology for upgrading aluminum sorted from shredder scrap is already either in industrial use or in the final stages of pilot plant development. However, the current automotive aluminum recycling infrastructure will need to adjust to deal with higher volumes of the metal from aluminum-intensive vehicles that will be appearing in shredder scrap -20 years from now.

Jan 1, 2000

By Douglas M. Matson, Rongbiao Gu, Christopher San Marchi, Anil Saigal

"Hydrogen embrittles most structural metals, although the form and magnitude of embrittlement depends on the source of the hydrogen as well as the stress in the metal. Hydrogen fuel cell systems typically store gaseous hydrogen fuel at high-pressure, which provides both a source of hydrogen and high stresses in the containment materials. Understanding and measuring the effects of hydrogen on the mechanical properties of common structural metals, especially fatigue properties, is important for safe, long-term operation of such systems. This work explores the use of thermography to efficiently and quantitatively evaluate hydrogen-assisted fatigue of type 304 austenitic stainless steel. In particular, thermographic analysis was used with rotating-beam fatigue testing and shown to provide repeatable results which are in general independent of test cycle frequency while reducing test times by several orders of magnitude. The effects of hydrogen were studied by thermally precharging fatigue test specimens in gaseous hydrogen prior to thermography-assisted fatigue testing and then compared to testing of non-charged specimens. Hydrogen-precharging increased the strength of this type 304 austenitic stainless steel and increased the fatigue life by a factor of about 50-100.IntroductionThe world is facing a severe energy and environmental challenge: how to provide competitive and clean energy for its citizens in light of an escalating global energy demand and concerns over energy supply security, climate change and local air pollution. As a carbon-free energy carrier, hydrogen provides a promising vector for storing and distributing renewable energy. Hydrogen is an important industrial gas that is used extensively in many industries. However, with growing demand for clean energy, hydrogen fuel cell systems are being developed for use in consumer products, such as fuel cell vehicles, which changes the landscape for safe design of high-pressure gaseous hydrogen systems."

Jan 1, 2012

By Ray D. Peterson, Garry G. Blagg

"Molten aluminum is routinely transported hundreds of miles to customers in large ""over-the-road"" crucibles. This is especially common for aluminum recycling organizations handling scrap and by-products. Receiving the aluminum in a molten form can save the customer time and money since in-house melting costs and capital equipment can be avoided. Additionally, the alloy can be on specification and nearly ready to use for the casting operation.A number of transport crucible designs are currently in use. The specifics of each design are based on the needs of the customer, the equipment used at both the producer and the consumer, and over-the-road transportation constraints. Crucibles are designed to maximize carrying capacity, and refractory life while minimizing heat flow and dead weight. These conflicting demands place difficult design criteria on the design engineer.This paper will review the basic advantages and disadvantages associated with molten metal transport, give examples of the design restrictions and examine several types design of crucibles currently in use."

Jan 1, 2000

By W. L. Dalmijn, E. A. Schokker, N. Fraunholcz, P. C. Rem

Many processes developed for the mechanical processing of Automotive Shredder Residue (ASR) suffer from high processing costs. We offer a distinct concept for low-cost mechanical processing still allowing high value-added recycling of the recovered materials. The basic idea behind this approach is to produce saleable pre-concentrates at the lowest possible costs that can be further processed in existing separation facilities. Our process includes screening, size reduction and magnetic separation. Preliminary studies showed that fibers in ASR are magnetic due to adhering rust particles allowing separation into a fiber fraction and a non-magnetic rigid fraction by high-intensity magnetic separation. The fiber fraction is most suited for thermal processing. The rigid fraction mainly consists of plastics and rubbers with up to 10 wt.-% of non-ferrous metals, some inert material and copper wires. This fraction is very well suited for mechanical processing by, e.g., sink-float separation in existing metal separation plants. The non-metal fraction can be processed further to recover the plastics and rubbers. The process proposed in this study is expected to be substantially cheaper than full thermal processing. In addition, as it mainly relies on existing separation facilities, it can be applied in the short term.

Jan 1, 2000

By Carlos Maurício Fontes Vieira, Sergio Neves Monteiro

"A ceramic body traditionally used to produce bricks and roofing tiles with kaolinitic clays was reformulated by the addition of sand and illitic clay. The objective was to obtain a ceramic product with better technological properties. Specimens were made by uniaxial press-molding at 20 MPa and then fired at 850, 900 and 950°C. The determined technological properties were: linear shrinkage, water absorption and flexural rupture strength. The results showed that both sand and illitic clay contribute to reduce the water absorption of the industrial clayey body. With respect to the flexural behavior, it was observed that the incorporation of sand decreased the mechanical strength. On the other hand, the illitic, incorporated in an amounts of 30 wt.% contributed to increase the mechanical strength of the clayey ceramic.IntroductionCeramic bodies industrially fabricated in the county of Campos, north of the State of Rio de Janeiro, in Brazil, are still empirically elaborated using a mixture of local clays. These clays are predominantly kaolinitic mineral in nature, associated with high plasticity and elevated weight loss during the firing stage. Due to the excessive plasticity of the ceramic bodies, dimensional defects, which occur after drying and firing are usually obtained. Moreover, the kaolinitic nature and the presence of aluminum hydroxide (gibbsite) confer a refractory behavior to the local clays, which impairs sintering during the firing operation. In the case of clay ceramic products for civil construction, this results in greater porosity associated with elevated values of water absorption and low mechanical strength [1,2]. To avoid these problems, it is necessary to reformulate the ceramic body composition. The addition of both non-plastic materials to reduce plasticity and fluxes to condition the refractoriness is a possible alternative.As an alternative to reduce the plasticity of clayey ceramics sand, which is predominantly constituted of silica, can be used. The incorporation of sand in amounts of up to 25 wt.% to a clayey ceramic body used for roofing tiles fabrication was studied by Vieira et al. [3]. In that work specimens were prepared by extrusion and fired at 850°C. The results indicated that in the pre-firing stages the sand improved the workability of the investigated clayey ceramic body and facilitates the drying stage. It was also observed that the incorporated sand significantly improved the physical and mechanical properties of the clayey ceramic after firing. On the other hand, the apport of flux oxides could be done by the use of illitic clays that have a higher amount of alkaline oxides in comparison with the kaolinitics clays."

Jan 1, 2013

By Richard M. RusselI, Jerry Sweeney

"The disposal of Aluminum slag wastes continues to challenge an otherwise environmentally beneficial and highly desirable industry - Aluminum Recycling. Slag wastes contain soluble salts that can be reused in aluminum smelting. Reclaiming salt is a logical first step in eliminating slag waste.Reclaiming salt flux has been conducted on a limited basis in the United States for reasons of economy. Practical methods and rising landfill tipping fees will increase the number of plants which opt to recover salts from slag wastes.The authors share their experiences in the design, operation and startup of a commercial scale flux reclamation plant operated by Tennessee Aluminum Processors at Mt. Pleasant Tennessee. This paper identifies three elements that allow practical operations:• Minimizing Evaporator Heat Duty• Simplifying Evaporator Operations• Potassium Chloride Fortification of the Recycled Salt"

Jan 1, 2000

By P. Hanniala, J. Sulanto

"The requirement for the reduction of sulphur dioxide emissions from copper smelters is becoming more and more important. Therefore, the most important question in smelting technology will be how to produce even, high strength SO2 gas in smelter and how to combine smelting and converting. The best sorution in certain cases is to eliminate converters totally.Outokumpu is already responding to this challenge. As a result of extensive research work, Outokumpu Oy has developed the Flash Smelting Process for direct smelting of blister copper from concentrates in one step.The newest process development is the Kennecott-Outokumpu Flash Converting process, where solidified copper matte is converted into blister copper. The production of low volume high SO2 content gases, separation of smelting and converting operations to allow increased on-line availability, and simplified process control are the major benefits of the process which translates to reduced smelter capital and operating costs.Also, it has been studied the use of the same Outokumpu furnace for smelting and converting alternately when the production capacity is low.In this paper, the developments and improvements of the Outokumpu Process are described from the operation and investment cost standpoints"

Jan 1, 1988

By Andreas Stieben, Pierre Lutomski, Wolfgang Bleck, Martin Fischer

"For steel investigation and development, exact knowledge about the microstructural state is required. The information gained from 2D images often can't properly reflect the real 3D microstructural properties. In order to gain reliable information for meaningful models, simulations and correlations, it is necessary to accompany standard metallography with 3D information, which, unfortunately, is very difficult to access. This article presents a procedure for serial sectioning in combination with light optical microscopy. Only standard metallographic tools are employed in combination with image manipulation freeware. 3D microstructural data were extracted from three multiphase steel grades and in two cases virtual 3D-models of microstructural phases were generated.Three Dimensions Of MicrostructuresSince the invention of steel, craftsmen, inventers and engineers tried to improve its properties and tailor them to the requirements of new developments. For systematic development and enhancement of steels, the capability to investigate its inner structure is highly important, because it represents the linchpin between material production and properties. By having an in-depth understanding how production conditions form the microstructure and also how the microstructural state determines the material properties, steel design can be drastically improved. With this knowledge, microstructures can be designed to provide target material properties and process conditions can be identified that form these structures. Due to the key role of microstructure, the capability to gain accurate information about it is indispensable. It is the task of metallography to access and extract descriptive quantitative microstructural data like fractions, sizes, shapes and distributions of the different constituents. The most commonly used investigation tool in metallography is the light optical microscope (LOM). Besides this tool, additional high resolution techniques like Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) have become increasingly important. With these and other available methods, extensive information on the microstructural state of a material can be gained. Unfortunately, most metallographic methods have a major loss of information systematically built in. Analyses of microstructures are usually performed on surfaces, i.e. on 2D areas that emerge by cutting through the 3D material structure. This means, a complete dimension of information is not taken into account. How serious this reduction of information is and how it can affect interpretation of structures is exemplarily demonstrated in figure 1, which displays the planar structure emerging from a random cut through a simple 3D structure. It is very difficult to deduce or even imagine the original spatial structure from which this projection emerged and it is impossible to reconstruct it with absolute certainty without further information. The image has emerged from a random cut through a 3D structure of stacked cubes that is displayed in figure 2. The area shown in figure I is outlined. Although artificially constructed, this example demonstrates how distorted and misleading the view on structures can become by ignoring a spatial dimension."

Jan 1, 2012

By P. R. Bruggink

"A quantitative tool has been developed to assess the impact of changes in recycling rates on the environmental impact of aluminum supply. It has been applied to the USA to forecast sources of aluminum scrap and to examine the impact of an increase in Old Scrap recovery on the USA supply system and the subsequent effect on the Life Cycle Impact of aluminum supply. The reported data for primary, secondary and import/export supply and product shipments for aluminum in the USA show a fairly good balance between supply and demand on average over the years. Therefore, it is reasonable to use the data, along with published estimates of average product lives, recycling rates and recoveries to draw conclusions about future aluminum scrap generation· and recovery. The Life Cycle Impacts of increasing post-consumer recovery rates to recover an additional 450,000 MT/yr (1 billion lb/yr) has been estimated using the model.The spreadsheet model upon which this work was based was developed in U.S. Customary units. Converting the figures to Metric units would have required converting the entire model and rebuilding the figures. I have chosen to leave the figures in U.S. Customary units. I apologize for any inconvenience this may cause."

Jan 1, 2000

By M. Sripathy, K. V. Sharmal

"The conventional fiber reinforced plastic does not participate in the plastic deformation or enter the large plastic deformation state during collision. On the other hand, sandwich structure allows more plastic deformation, which improves the energy absorption efficiency. The objective of this study is focused on the investigation of the crushing of sandwich structure made from sisal / coir / bamboo/ glass fabrics as reinforcement and with polyester resin to form the composites skin and with polyurethane foam as the core. Experiments were conducted, showing that the underlying crushing mechanism of sandwich structures is very different from that of solid-section thin-walled structures. When a sandwich is subjected to crushing, the core deforms in the shear mode and the face bends independently. The damage is through the width zone of crushed foam core accompanied by a residual crushing in the foam. It is shown that such damage causes a significant reduction of compressive strength. Results show that glass/polyester and bamboo/polyester skin based sandwich structures have superior compressive strength. Coir /polyester based sandwich structure come next to glass/polyester sandwich structures in this aspect which is then followed by Sisal /polyester based sandwich structures.IntroductionCellular polymeric foam sandwich structures are often employed in shock mitigating applications. The cellular polymeric foam has several favorable properties, such as, low density, relatively high strength-to weight ratio and a significant degree of crushability. This high crushability is the result of the large void ratio in such materials, which also facilitates the collapse of cell walls via bending and buckling [1]. A few feasibility studies on FRP sandwich panels show that the panels efficiently provided high mechanical performance for minimum weight [2]."

Jan 1, 2012

By Jared Ball, Benjamin Hogg

There are over 100 process parameters that can be monitored during a single Peirce-Smith (PS) converter batch operation. To support a consistent operation it is important to select the correct Key Performance Indicators (KPI’s) to monitor. They should be strategically chosen to drive the desired behaviour with enough flexibility to endure process variations. At the Xstrata Copper Smelter in Mount Isa most of the PS converter operators have very little experience and are often lacking in the appropriate education or training to properly understand the process. For this reason 10 simple KPI’s were chosen that could be easily comprehended and monitored by all smelter personnel. KPI compliance has been supported by relevant project work in the converter area. Charge sequence trials have been performed in an effort to reduce splash and optimise activity time. The online measurement of full and empty ladle weights has enabled an immediate indication of skull size, skim/slag carryover, and metal loss.

Jan 1, 2009

By Kenji Monden

"In order to obtain basic data for the development of highly thermally conductive composite materials, the thermal conductivity of a resin composite material with an Aluminum Nitride filler was assessed. Several different measurement techniques such as the xenon flash and the temperature wave thermometric analysis method were employed to gather data on these composites. An excellent match between theoretical and experimental data was achieved by employing a predictive expression that takes into account the effect of percolation on thermal conductivity.IntroductionA thermal solution composite is made by incorporating dense inorganic fillers with high thermal conductivity into a resin. Because the composite materials have high thermal conductivities, they have been used in electrical products that generate excessive thermal energy during operation, such as inverters, amplifiers and motor drivers. They function as electrically insulating and thermally conducting parts of the electric modules. As the uses of thermal solutions are expanded, composites of higher thermal conductivities will be required. The aim of this work was to investigate, evaluate, and try to predict the influence of key parameters on thermal conductivity and diffusivity. This was achieved by analyzing the effect of both volume fraction and shape of Aluminum Nitride ceramic fillers and measuring the thermal conductivity. In addition, the influence of percolation on thermal conductivity is considered. The thermal conductivity of the composites is discussed by employing a predictive equation using literature data of thermal conductivities for both the filler and resin. As well as thermal conductivity measurements the effect of volume fraction of the filler was also explored.ExperimentalSpecimen PreparationThe composite samples were prepared from silicone resin and Aluminum Nitride (AlN) fillers. The AlN fillers with an average particle size of 20 µm are shown in Figure 1. The mean diameters of the AlN particles used are given in Table I. For comparison the AlN fillers with an average particle size of 5 µm are shown in Figure 2. A planetary centrifugal mixer was used for simultaneously dispersing the components uniformly and de-aerating the mixture. After mixing, these materials were placed in a silicone rubber case and cured at 150 °C for 1 hour."

Jan 1, 2013

By Daniel E. Groteke

This paper describes a new technology which allows aluminum drosses to be processed at the generating melting furnace to recover available metallic values. The systems, offered in both manual and automatic modes, are capable of processing quantities ranging from 15 to 200 lb. per cycle, and recovering up to 90% of the aluminum with a combination of agitation and chemical reactions. In the automatic mode, the separation of molten alloy and de-metallized dross is achieved in less than five minutes process time. The recovered alloy, of largely unchanged composition, may then be returned while at elevated temperature to the original melting furnace to achieve an additional saving of energy.

Jan 1, 2000

By Susumu Okabe

The Mitsubishi Continuous Copper Smelting/Converting Process employs an electric furnace for settling the slag/matte mixture formed in the smelting furnace. In order to improve the separation of slag and matte and to minimize power consumption, the design and the operating conditions of the electric furnace should be optimized. As the first step, numerical heat and fluid flow analysis of the melts was carried out based on the distribution of current density and Joule?'s heat obtained by the electric field calculation. For these calculations, 3-D body fitted coordinate system and a finite volume method were applied. Using the developed numerical model, the flow pattern analysis by pulse input of a tracer element was simulated. It was found that a strong thermal convection of the molten slag exists around the electrodes due to the concentrated Joule's heat generation in a small area just under the electrodes, and this strongly affects the flow pattern in the furnace. The calculation results were compared with the data obtained from 'a plant test.

Jan 1, 1998

By Robert E. Brown

Magnesium recycling has been used to recover both new scrap and old scrap. It was used extensively in Germany during WWII to expand the magnesium supply. There were a large number of magnesium recyclers in the US who got their start smelting old scrap, old airplanes and old waste dumps from the WWII build up. As the world magnesium industry dwindled, only a few companies were left that did magnesium recycling as a primary business. The sand foundries tended to recycle of their production scrap in their melting furnaces. Even the original die casters tended to put scrap directly back into melting furnaces at the die casting machines. As high purity alloys were developed and the use of die castings in automotive work increased, the tendency was to let the magnesium recyclers convert the scrap back to high quality ingot. Automotive use has grown because of the low density of magnesium. This property is the one of the biggest problems to overcome in shipping scrap. Gates and runners from die casting are very irregular shapes and it is very hard to load a truck with enough material to get a low shipping cost per pound. Recent new equipment companies have developed magnesium equipment that is specifically designed to recycle, refine and cast secondary magnesium metal. These melt cells are supplied as integrated units to magnesium casting sites. The cost and effectiveness of this approach will be discussed.

Jan 1, 2000

By Tarasankar DebRoy

Professor Robertson’s recognized research on metallurgical thermodynamics and kinetics for over 40 years facilitated the emergence of rigorous quantitative understanding of many complex metallurgical processes. The author had the opportunity to work with Professor Robertson on liquid metals in the 1970s. This paper is intended to review the advances in the quantitative understanding of welding processes and weld metal attributes in recent decades. Over this period, phenomenological models have been developed to better understand and control various welding processes and the structure and properties of welded materials. Numerical models and animations of melting, solidification and the evolution of micro and macro-structural features will be presented to critically examine their impact on the practice of welding and the underlying science.

Jan 1, 2014

By P. G. Schirk, D. J. Roth

ALTEK has developed a processing system that can receive large pieces of dross & bath, of various metal contents, and reduce and separate these highly metallic concentrates into oxides and non-metallics. This system achieves these results without grinding the metallics into fines. Its unique feature results in the preservation of metallic unit in its largest possible size, which allows for maximum .metal recoveries. The Tumbler, an ALTEK-Didion International joint development, and the ALTEK High Velocity Impacting System (HVIS) are the key elements to this process. This paper will explore the advantage of this cold cleaning system over the direct melting of the raw dross in the reduction of landfill waste. The system also works well for removal of the aluminum from bath from primary smelters.

Jan 1, 2000