Search Documents

By Mark Jolly

"Instead of using the traditional batch casting process, the CRIMSON [1] (Constrained Rapid Induction Melting Single Shot Up-Casting) method employs a high-powered furnace to melt just enough metal to fill a single mould in a closed crucible. The crucible is transferred to a station for computer-controlled counter gravity filling of the mould for optimum filling and solidification. The CRIMSON method therefore holds the liquid aluminium for a minimum of time drastically reducing the energy losses attributed to holding the metal at temperature. With the rapid melting times achieved, of the order of minutes, there isn’t a long time at temperature for hydrogen to be absorbed or for thick layers of oxide to form. The metal is never allowed to fall under gravity and therefore any oxide formed is not entrained within the liquid. Thus higher quality castings are produced leading to a reduction in scrap rate and reduced overall energy losses.IntroductionEngineers at the University of Birmingham, England, with local company, NTec, have invented a new casting process that will reduce the energy costs of light-metal foundries. The technology, entitled CRIMSON, means that foundries need only heat the quantity of metal required to fill a single mould rather than large batches that use unnecessary energy and create waste. The complete concept of CRIMSON requires a change of philosophy in the approach to casting and requires the user to think holistically in order to reap the full benefits from the process. This paper will discuss the various aspects of energy wastage within the foundry sector and discusses the processes whereby the energy can be reduced. Primarily the author focuses on the aluminium sector but CRIMSON can be applied to many of the non-ferrous “light” alloys. Ferrous materials and non-ferrous “heavy” alloys can also benefit from some of the ideas but not necessarily directly from the application of CRIMSON."

Jan 1, 2010

By Xue Wang, Callie Babbitt, Chelsea Bailey, Matt Ganter, Gabrielle Gaustad, Brian Landi

"Current trends, motivated by fossil fuel dependence and unprecedented greenhouse gas (GHG) emissions, show lithium-ion batteries (LIBs) emerging as a competitive energy storage technology due to higher power and energy densities compared to Pb-acid and Ni-metal hydride chemistries. These trends may be of concern, however, as environmental impacts are not well understood for either the LIB itself, or for the nanoparticles consumed or released during the battery's production, use, or end-of-life. This study combines economic modeling, dynamic material flow analysis, and fundamental material characterization methods in order to quantify some of the economic and environmental trade-offs for LIBs at their end-of-life. As expected, results show that as chemistries transition from Li-Co based cathodes to Li based Fe, Mn, and S cathodes, LIB recovery value correlates to the value of the raw materials used. These initial results aim to inform collection policies being proposed currently as well as enable future deployment of novel recycling techniques.IntroductionGlobal fossil fuel dependence and unprecedented GHG emissions have led to increasing attention on energy alternatives, for both electricity production and personal transportation. However, development of renewable energy systems is contingent on concurrent technological development of energy storage systems, primarily batteries used for power grid load-leveling, renewable energy storage, and hybrid and battery electric vehicles. In this sector, lithium-ion batteries (LIBs) are emerging as a competitive technology due to higher power and energy densities compared to lead-acid and nickelmetal hydride chemistries[!]. LIBs represent close to 20% of the total rechargeable battery market and 75% of the portable rechargeable battery market, which is the fastest growing segment of the rechargeable battery market, with a 20% global growth in 2008 [2].This surge in production ofLIBs indicates a looming waste problem; total waste from Li-ion batteries has likely grown substantially from the 500 metric tons estimated in 2003 [3]. Figure IA shows the substantial increase in world-wide lithium production that has occurred in the last several decades with batteries making up the largest share of applications (Figure lB). California and New York state legislators have attempted to proactively address this looming waste by issuing diposal bans on rechargeable batteries in their states[4, 5]. However, quantification of the costs involved in collection, transportation, and processing of these materials has not been examined in depth."

Jan 1, 2012

By Songsong Wang

Recently, replacing Pierce-Smith converting process with the oxygen bottom-blowing continuous converting technology has become a new research focus. Based on the principle of Gibbs free energy minimization, the thermodynamic model of oxygen bottom-blowing continuous converting multiphase equilibrium system has been established. The elements distribution behavior is calculated at the same burden composition and operation parameters as the industrial production. The results show that the absolute errors of the mass fraction (wt%) of Cu, Fe, S, Pb, Zn, As, Sb, Bi in crude copper are 0.06, 0.0030, 0.070, 0.38, 0.39, 0.020, 0.017, 0.034, 0.010, respectively, and the absolute errors of the mass fraction (wt%) of Cu, Fe, S, Pb, Zn, As, Sb, Bi in slag are 0.53, 0.81, 0.020, 0.23, 2.5, 0.0048, 0.0010, 0.0030, 1.49, respectively. The calculated results agree well with the actual industrial production data, indicating that the model can be well applied in the oxygen bottom-blowing continuous converting practice.

By Senlin Xie, Wanlin Wang, Lejun Zhou

"The innovative development of multiphase slag in hot-metal treatment has attracted considerable attention due to the reduction of CaO consumption and minimal environmental emission. In order to improve the efficiency of dephosphorization and to reutilize the waste-slag as an alternative source of phosphate ores, it is important to increase the distribution ratio of P2Os between the solid solution (2CaO· SiO2-3CaO· P2O 5) and liquid slag. An investigation was carried out to study the effects ofNa2O and B2O3 on the distribution ratio of P2Os, the results indicated that the increase ofNa2O would enhance the distribution ratio of P2Os with the formation of solid solution (2CaO·SiO2-Na2O·2CaO·P2Os), while B2O3 has the opposite function, and changes the morphology of solid solution. The study would provide an instructive way for the design of multiphase slag and re-utilization of waste-slag.IntroductionIn order to meet the increasing demand for high quality low-phosphorus steel, it requires a high efficient hot metal dephosphorization process. The current slag system for hot metal treatment contains large amount of solid CaO dispersed in liquid slag, which introduced a large amount of CaO consumption due to its low solubility, especially when CaF2 was restricted due to the environmental concerns. Therefore, new refming method to improve the utilization efficiency of CaO by using a solid/liquid coexisting multiphase slag was proposed, and the studies regarding to solid solution formation mechanism, mass transfer behavior of phosphorus and the phase relationship for multi-phase slag have been conducted. [1-6]Normally, hot metal dephosphorization slag consists of CaO--SiOz-FeO--P2O 5, and it has been approved that 2CaO·SiO2 forms a solid solution with 3CaO·P2Os at the hot metal treatment temperature over a wide range of compositions. [7] Kitamura et al [8] pointed out that the (2CaO·SiO2-3CaO·P2O 5) solid solution plays an important role in dephosphorization, and it has been regarded as an absorbents for phosphorus to lower the phosphorus content in liquid phase, which makes it more capable for future dephosphorization. l Besides, the multiphase slag has the potential to be recycled as a source of phosphorus, if the (2CaO· SiO2-3CaO· P2O 5) solid solution could contain high phosphorus content, and it can be separated from FeiO matrix 8hase due to the large difference of their magnetic properties under the strong magnetic field. [10, 11]"

Jan 1, 2014

By L. R. Verney

A number of interrelated factors influence the economics of the sulphide smelting of copper, lead, zinc and nickel. This paper discusses these factors, mainly from a US point of view, and shows how they affect the cost of construction and operation of new and existing plants. The paper shows how metallurgical plant construction costs and the consumer price index have increased at a much faster rate than metal prices thereby making some metal mining and production operations within the USA, Canada and the EEC less profitable than operations elsewhere. This in turn inhibits new "grass roots" metallurgical developments. It is explained how retrofit of existing pyrometallurgical plants can be a more viable development than the construction of "green field" plants, especially if such retrofit improves, energy efficiencies, overall operating costs and reduces emissions of sulphur and other toxic wastes. Some aspects of metallurgical plant operation are examined, especially for copper and nickel, to show how changes in operating practices may develop in order to improve overall smelting economies, especially when developed in conjunction with objective retrofit. The paper also examines some financial aspects, especially insofar as the disparity between terms for loans offered to third world countries and the USA and the EEC are concerned and also comments upon the need, especially within the USA, for legislation to permit rapid depreciation of capital. Specific comments are made about environmental aspects, including the lack of uniformity of pollution control legislation and how environmental considerations may have some bearing of the location of future smelting operations.

Jan 1, 1983

By T. Ueno

Naoshima Smelter & Refinery of Mitsubishi Materials Crop. commissioned a new Mitsubishi continuous copper smelter in May 1991. Process offgas volume of the conventional reverberatory furnace line, one of the previous smelters having been shut down, was very large and thus two acid plants had been operated. It was expected that the offgas volume would be reduced at the new smelter to about a half of the sum of those from previous two 1 smelters and the sulfur dioxide strength would be increased. So various alternatives were studied to minimize the operation cost. And it was decided to utilize both of the plants with minor modifications by diluting the gas either with air or with dilute gases. The acid plants now receive offgases from the new copper smelter, a sintering machine of a lead smelter and a decomposer of waste acid. The paper discusses plant design, operation, improvements and modifications realized in relation with the retrofitting of the copper smelter.

Jan 1, 1992

Based on experimental and computer simulation results from our group, we report a systematic, atomic level analysis of carbon dissolution from carbonaceous materials in molten iron. Experimental results on graphite/Fe-C-S system were obtained using carbon dissolution studies, XRD and FESEM investigations and were supplemented with Monte Carlo simulations. Three basic mechanisms, namely carbon atom dissociation rate, interfacial phenomena and mass transfer in the melt were found to be responsible for the overall dissolution process. While mass transfer in the melt is governed by the concentration gradients, melt composition and temperature; impurities present in ash play a significant role in the interfacial phenomena. For less ordered forms of carbonaceous materials, carbon atom dissociation rate depends strongly on the degree of long-range order and is an important rate controlling mechanism in the overall dissolution process. A systematic comparison of dissolution rates for a variety of coal-chars, natural and synthetic graphites has been carried out in an attempt to identify rate-controlling mechanisms. The structure of the carbonaceous material appears to be an important underlying factor in the carbon dissolution process.

Jan 1, 2003

By Mark Tsirlin

Kinetics of the initial oxidation stages of diffusive silicide coatings on 8 molybdenum and niobium at 1100 - 1700 and under the pressure of 400 and 1330 Pa has been studied using methods of gravimetry and gas phase analysis of oxygen, as well as by SEK, XRD and EDMA methods. The first oxidation stage described by asymptotic equation in case of NbSi coating changed over to the stage described by parabolic equation. The asymptotic law was shown to depend on non - stationary conditions on the oxide layer boundaries. Interconnection between silicides and quartz structures, on the one hand, and peculiarities of oxidation kinetics, on the other, is [discussed. The possibility of estimation oxygen atom jump frequency in quartz and fractions of oxygen reacting with metal and with silicon proceeding from the analysis of the kinetic data was ascertained. Conditions of oxidation kine- tics transfer from asymptotic (or parabolic) stage to a non - protective "linear" stage, associated with volatile ~roduct formation, are also discussed.

Jan 1, 1995

By K. Morsi

Titanium-titanium boride whisker (TiBw) composites are emerging as strong candidate materials for advanced applications within the automotive, aerospace and defense industries. Although increasing TiBw volume fraction improves the specific stiffness and wear resistance of titanium, it is usually on the expense of fracture toughness and ductility especially at increased volume fractions of reinforcements where whiskers interlock. This research addresses strategies for microstructural design that may overcome these shortcomings, by generating titanium composites that are locally reinforced with TiBw through in-situ reaction in segregated regions of the microstructure and separated by ductile Ti matrix. The effect of varying composite reinforcement particle sizes (i.e. size of the reinforced regions) on the pressure-less sintering of these dual matrix composites is discussed. Electric current activation was also used to generate high density dual matrix composites and a new simultaneous imaging and modulus mapping technique was used to characterize these unique microstructures.

Jan 1, 2008

By Ramana G. Reddy

Thermodynamic modeling and experimental study on impurity capacities and their distribution between mattes or metal and slags in smelting, converting and refining of non-ferrous metals was discussed. A brief review on the recent developments in copper smelting and converting is presented. The analysis showed that, copper smelting capacity increased by a factor of 10 since 60's, smelting rate increased by a factor of more than 5 and process fuel equivalent decreased by a factor of 2. A thermodynamic model for prediction of impurities capacities in slags and their distribution in mattes and slags was developed. The impurities capacities (i.e. sulfur and arsenic) of slags were calculated a priori with no adjustable parameters using the Reddy-Blander model. The capacities predictions were made in a wide range of matte and slag compositions, Pso, and temperatures in conditions pertaining to copper and lead industrial slags. The calculated results for sulfide and arsenate capacities are in good agreement with the available experimental and industrial copper and lead industrial slags data. The sulfide and arsenate capacities in copper slags (fayalite, ferrite and olivine) and lead slags are reviewed. The application of RB model predicted ratios of 02 and S2 partial pressures in industrial copper smelting processes are discussed. Application of this model for the prediction of Sb, Bi and other impurity capacities and their distribution ratios in mattes or metal and slags, in industrial smelting and refining processes is discussed.

Jan 1, 2003

By Run Huang, Xuewei Lv, Songli Liu, Chenguang Bai

"Titanium alloy was prepared from titania-bearing blast furnace slag (Ti-BF slag) by aluminothermic process in an induction furnace. The effects of aluminum amount on the titanium silicon yield and titanium recovery ratio were studied. The phase transformation and chemical composition of the prepared alloy were investigated by X-ray diffractometry (XRD) and X-ray fluorescence (XRF) respectively. It was found that the mass fraction of silicon and aluminum increased with increasing the aluminum amount, however, the mass fraction of titanium increased first and then decreased with increasing the aluminum amount. Furthermore, both the titanium alloy yield and titanium recovery ratio increased with the increase of aluminum amount. The main phases of the alloy were TixSiy and AlTi3. The titanium alloy samples prepared in various conditions had a composition (wt.%): 38–50% Ti, 29-34% Si, 4-11 Al%, 1.6-2.2 Mn%.IntroductionPanzhihua and Xichang regions in the southwest of China are rich in vanadium-titanium magnetite containing iron, vanadium, titanium and gangue. According to the characteristics of the resource, iron and vanadium are successfully recovered with a blast furnace process and a converter process. However, most content of titanium are entered in the blast furnace slag with TiO2 22% -26% and metallic Fe 2%–6% called Ti-BF slag. Due to the dispersed distribution of Ti in various fine grained mineral phases with a complex combination between Ca, Al and Si, it is difficult to recover the Ti components[1]. This slag is generated at a current rate of 3.6 million tons per year, which adds to the existing 70 million tons of slag produced so far[2]. The slag has had to be piled as large as the mountains, which not only waste of resources but also cause a pollution of the environment. Therefore, the study of integrated utilizing Ti-BF slag has become very significant."

Jan 1, 2012

By Kiyoshi Shibata

A new assessment model has been proposed for metal production and its recycling system. The model consists of three processes, smelting of ore, cascading and upgrading of metal scrap. The present approach is to assess the total energy consumption of the system, by introducing two equations for describing the relationships between critical impurity content and the mass of production or scrap recycling. The total energy consumption in the system can be described as a function of recycling rate and performance of the upgrading process. The present model suggests that the impurity removal efficiency and yield in the upgrading process are essential to reduce the energy consumption in the systems. Especially, such points should be explicitly controlled in recycling of aluminum. The potential capability of this model was also discussed by obtaining several quantitative information required for the process design and the operational control of beneficial recycling of metals.

Jan 1, 1998

By A. Arenas-Flores, Pandiyan Thangarasu, J. P. Hernández-Lara, F. R. Barrientos-Hernández, J. A. Romero-Serrano, A. Hernández-Ramírez, M. Pérez-Labra

BaTiO3 doped with Gd3+, was synthesized from BaCO3, TiO2, and Gd2O3 as powders using the solid state reaction method (Ba1-xGdxTi1-x/4O3). The milling of the precursors was performed in an agate mortar with acetone as control means and compositions x = 0.001, 0.005, 0.05, 0.15, 0.25, 0.35 Gd3+ (wt%). Firstly, the powder mixture was decarbonated at 900 °C for 8 h, after it was sintered at 1400 °C for 5 h. Tetragonality of synthesized BaTiO3 doped with Gd3+ was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy (RS). Subsequently, the powders sintered were uniaxially compacted cold until to obtain pellets of about 10 mm in diameter; which again were sintered at 1400 °C for 4 h. XRD patterns and Raman spectra results revealed that the crystal phase of the obtained particles was predominately tetragonal BaTiO3.

Mar 1, 2017

By Xie Zhang, Jiang Diao, Xin Qiu, Lu Jiang, Bing Xie, Hong-Yi Li

"Duplex converter process, in which the first converter is used for removing phosphorus from hot metal (De-P), is an important way to produce low P-content and ultra-low P-content steels. In order to improve phosphorization removal and formation of slag with high basicity at relatively low temperature during dephosphorization converter process, effects of temperature, silicon content in hot metal and varied compositions of the De-P converter slag on phosphorus distribution between the slag and hot metal were investigated with thermodynamic calculations and by laboratory scale experiments in present work. Results showed that phosphorus distribution ratio between slag and metal was varied in 10.6~26.6 when basicity of the slag was in the range of 1.5~2.1 at 1370, and the distribution ratio was increased with increasing basicity and Fe10 content in the slag.IntroductionIt is known that phosphorus exists in steel in the form of solid solution, which can significantly improve strength and hardness of steel at room temperature. However, the plasticity and toughness of steel, especially the low temperature plasticity is sharply reduced and leads to high ductile-brittle transition temperature. This phenomenon is commonly known as cold brittleness of steel [1~3]. Hence, phosphorus should be removed as much as possible in the steelmaking process, because it is generally harmful to the iron and steel products."

Jan 1, 2013

By Henry Hu

In high pressure die casting processes, proper control of temperature die yields a high casting production rate and superior quality components, Die temperature is usually influenced by various die design and process parameters such as size and location of intemal water cooling lines, flow rates of cooling lines, and pouring temperature of molten metal. Among them, the cooling water flow rate plays a major role in controlling thermal pattern of the die_ In order to develop an effective control strategy, data of local die temperature must be collected and analyzed, In this study, a PC-based data acquisition and control system (DACS) for die temperature control has been designed, and established, The developed DACS has three input channels for temperature signals and one input channel for water flow rate signals, as well as one output channel for a water pump, and is capable of displaying data in both curve format and value format. Implementation of the DACS in a laboratory setup has also been attempted, It should be pointed out that more advanced control mechanisms can be potentially integrated into this system in future,

Jan 1, 2003

By Joseph Sofra

It has become increasingly evident that sustainable metals production in the 21" century requires producers to balance the needs of cost effective, high value production with that of responsible plant operation. This is becoming more difficult as lower grade and more complex feed materials, including recycled scrap and residues, arc being processed to reduce production costs and decrease exposure to primary metal market fluctuations. One particular facet of the metals industry facing these challenges in the 21 st century arc copper producers. The recent steady decline in the copper price has seen the industry cut expenditure, tighten control on income streams and focus on high returns on capital investment. For these reasons copper producers arc looking towards flexible technologies that can deliver high value products, with minimal environmental impact at low capital and low sustainable operating costs. Ausmelt's Top Submerged Lancing (TSL) technology for copper production is a low cost, proven technology for the processing of both primary and secondary copper materials. Both the smelting and converting operations introduce significant advantages in environmental performance, improved process efficiencies and high rates of metal recovery. Ausmelt has made significant gains in the past 4 years in establishing a strong market position for its copper technology. New installations in China, South Africa and India as well as existing operations in Zimbabwe and China have demonstrated its effectiveness. This paper reviews the application of Ausmelt Technology for both smelting and converting of primary and secondary sources. It discusses Ausmelt's design and implementation philosophy, and how this philosophy meshes with the needs of the end user.

Jan 1, 2003

By Robert C. Laudon

Spectral reflectance data for 335 minerals, including 228 minimum-maximum combinations for anisotropic minerals giving a total of 563 data sets, have been collected from the literature and combined into a single database. Quantitative color values for x, y, Y, Ad , and Pe referred to ICI standard i11uminant C have been calculated from the spectral reflectance data and are included in the database. The programs plot spectral reflectance curves together with all quantitative color data for each mineral in the database. The plots and data can be directed to a dot-matrix printer such that a databook of quantitative color and spectral reflectance having one mineral per page can be generated for the ore microscopy laboratory. In addition, by sorting the database and grouping the minerals, groups or individual minerals can be plotted on the chromaticity diagram, and this plot can also be sent to a dot-matrix printer. The programs are written in compiled BASICA for an IBM-PC with graphics capabilities and at least 128KB random access memory (RAM). The databases are accessible either through the BASIC programs or through any commercial database system capable of loading and writing to an ASCII format sequential file. The programs and database are available by sending a blank diskette and self addressed, stamped envelope to the authors.

Jan 1, 1987

By K. C. Liddell, B. Dou

"In producing multilayer films for magnetic data storage applications, the interfacial roughness must be controlled in order to obtain high quality materials with reproducible properties. The present understanding of the effect of roughness on multilayer properties such as magnetoresistance is sketchy, particularly for electrodeposited films. In this study, quantitative atomic force microscopy was used to characterize surface morphology before and after Ni films of varying thickness were deposited on Cu cathodes. A multinuclear multilayer growth mechanism is supported by both the deposition conditions and the AFM images, and a multinuclear multilayer model gave a satisfactory fit to measurements of the density of peaks on ultrathin Ni films between 0 and 8 nm thick.Alloys consisting of alternating ferro-and paramagnetic layers have begun to replace Permalloy in the sensing elements of magnetic hard drives. The operating principle of the new read heads is giant magnetoresistance (GMR), and they are smaller and more sensitive than previous inductive heads (1). Experimental studies on sputtered multilayers have emphasized the role of layer thickness and interlayer roughness in determining the presence and size of the GMR effect (e.g., 2,3,4,5,6). However, roughness in electrodeposited multilayers has rarely been measured, even though read heads are likely to continue to be made by this process for some time to come. Cu/Ni can be considered a model system for understanding processing-microstructure-property relationships in electrodeposited multilayers and is the most widely investigated of all such systems (e.g., 7,8,9,10,11,12). Nevertheless, the roughness of the interfaces in Cu/Ni electrodeposits has not been systematically characterized by quantitative techniques, and in all studies reported so far, the total deposit thicknesses were considerably greater than the 10 nm needed for most sensor applications (1). The thinnest such films were about 50 nm (7)."

Jan 1, 1998

By Yuanbing Ling

Keywords: Calcium sulfate, Sulfuric acid, Phase transformations, Thermodynamic analysis As part of a boarder research project, seeking the development of a cost-effective process for direct production of the high value material, -calcium sulfate hemihydrate, from sulfuric acid at atmospheric as opposed to elevated pressure conditions, the fundamental work presented here has been undertaken. This includes experimental monitoring of phase transformation reactions and thermodynamic analysis of the relationships among the various phases, namely, calcium sulfate dihydrate, hemihydrate and anhydrite in aqueous sulfuric acid solution at temperatures ranging from 20oC to boiling point.

Jan 1, 2004

By Linfeng Zhou, Yuanbo Zhang, Rong Sun, Guanghui Li, Zhiwei Peng

The volatilization behavior of rhenium in the process of oxidative roasting of a molybdenite concentrate with 43.55 wt.% Mo and 321 g/t Re is explored based on identifying the relationship between volatilization of sulfur and rhenium. The results show that rhenium volatizes after sulfur and precise control of operating variables plays an important role in separating rhenium from molybdenite concentrate. When the roasting parameters are optimized as follows: roasting temperature 600 oC, roasting time 2 h, roasting atmosphere air, the volatilization rate of rhenium reaches 89.26%. In the process of solidification roasting, the volatilization rate of rhenium decreased almost to zero when the ratio of slaked lime/molybdenum concentrate was 10% excess to the stoichiometric requirement at 600 oC for 2 h.

Jan 1, 2016