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By Shaolong Chen

Feeding dry sulfide concentrate into smelting furnaces enhances process performance and reduces the energy consumption and exhaust gas flow. Direct heated rotary dryers and flash dryers have being replaced by rotary steam dryers featured by very low wear rate of the pipe heating elements and long maintenance interval. Impact of the drying processes on the environment receives more and more attention as the emission legislation tightens. In this regard, environmental factors such as SO2, CO2, dust and gas flow among rotary dryers, flash dryers and steam dryers were compared. Selection of a rotary steam dryer for copper and nickel concentrate drying would be an ideal solution to reduce the pollution of exhaust gas, as drying is achieved by indirect contact to the steam at relatively low drying temperature and as the off-gas contains almost only water vapor and air. The emissions can be significantly reduced and only small and simple off-gas handling units are needed.

Jan 1, 2006

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 Ximena Massone

Chile is the most important copper producer in the world and the mining sector plays a key value in its economy. However, at present the country does not have a satisfactory set of regulations about closure and restoration of mining operations. In our country many mining operations will, in the near future, shut down their activities, therefore, it is of utmost importance to elaborate and enforce a set of regulations to prevent risks and to protect the environment. The present study is focused on reviewing and analyzing the existing national regulations about the closure of mining operations and preparing a comparative analysis with other international regulations of countries with mining experience. The final results of the study will be a legal proposal to regulate the closure of mining operations in Chile, aiming at minimizing the potential environmental adverse impact, internalizing the social costs by the relevant operators and defining all aspects of liability for the environmental damage.

Jan 1, 1999

By R. D. Prengaman

Wrought lead-calcium-tin anodes developed by RSR Corporation have improved the performance compared with the other lead alloy anodes. These anodes have been in continuous service at various locations around the world for as long as fourteen years. Calcium provides mechanical strength to the anode to prevent the deformation while tin increases the mechanical strength, reduces the rate of corrosion, prevents the formation of non-conducting layers on the anode surface, and dramatically improves the conductivity of the anode. Tin is also instrumental in developing the unique rolled structure of the anode which leads to the reduced rates of corrosion, longer life, and improved oxygen evolution. Cobalt additions to the electrolyte further enhance the oxygen evolution and improve the anode life. Higher current densities and higher operating temperatures reduce the anode life. The unique patented method of attaching the rolled anode sheet to the bus bar substantially reduces the resistance of this important joint and offers the substantial savings in power over the life of anode.

Jan 1, 1999

By A. K. Kyllo

The use of Composite Furnace Module cooling systems has been shown to give improved refractory performance in a number of above bath locations in WMC flash furnaces. To test the behaviour of modules in contact with a melt, a set of instrumented modules have been installed in the reaction shaft of a. nickel flash furnace. The location was chosen to provide a suitably harsh environment to ensure rigorous testing, while still allowing relatively easy access for module installation. The modules were continuously monitored to provide information on the module performance, as well as the temperature in the shaft itself. The shaft temperature showed significant transient behaviour, which resulted in heat fluxes through the modules ranging from 10 to 92 kW m-2. The modules were capable of handling the highest heat flux with no risk of the coolant boiling. This paper details the design and operation of the modules over a period of seven weeks.

Jan 1, 1999

By J. L. Bill

The capacity of the Mount Isa Mimes Limited Copper Smelter was expanded in 1998 from 180,000 tomes per year of anode copper to 265,000 tpy. It is based on the innovative Copper ISASMELT technology, which currently treats concentrate at up to 184 tph. Increasing lance-air oxygen enrichment increased the ISASMELT furnace feed rate from 102 to 184 tph. The increased feed rate was achieved without any modifications to the ISASMELT furnace. The first refractory campaign following the upgrade lasted for two years. Future campaign lives of four years or more--without water cooling-are possible. Other Copper ISASMELT furnaces are operating in the U.S.A., Belgium, and India, with additional smelters under construction in China and Germany. In addition, Lead ISASMELT furnaces are operating in the U.K. and Malaysia. The paper discusses the performance of the MIM Copper ISASMELT furnace and the Copper Smelter since the expansion, including operating data and refractory performance.

Jan 1, 2002

By Kenji Monden

"The creep properties of tin-based lead-free solders Sn3.0AgO.5Cu and SnO.7CuO.1Ni and lead solders 10Sn90Pb and 50Sn50Pb were investigated at temperatures between 298 K and 398 K. The creep-rupture time decreases with increasing initial stress and temperature. The analysis of the solder creep curves uses the Omega method. The creep rate E is expressed by following formula: 1n ? = 1n ?0 + O?, where ?0 and O are experimentally determined. The parameter Eo increases with increasing initial stress and temperature. The activation energy for ?0 is 108 kJ/mol for Sn3.0Ag0.5Cu and 85 kJ/mol for SnO.7CuO.INi. These energies suggest that the lattice diffusion of tin is dominant. The energy of 1OSn90Pb is 37 kJ/mol and that of 50Sn50Pb is 67 kJ/mol. The creep-rupture time is calculated using the parameters, ?0 and O. The calculated creep-rupture time is in good agreement with the measured creep-rupture time.IntroductionLead-free solders are replacing traditional tin-lead solders as part of a major trend toward protecting the earth's environment. However, tin-lead solders are currently needed for a high temperature range. Since creep is the main deformation mechanism in solder joints, understanding a constitutive model for creep and examining creep data for solders are important for reliability analysis of solder joints. A steady-state creep equation is generally used for solders [1,2], and it supposes that the secondary-, or minimum-, creep rate occupies the entire creep life. However, secondary creep accounts for only about 15 % to 40 % of the entire creep life for solders. Thus, the equation may not represent the entire creep life."

Jan 1, 2012

By Thomas J. O'Keefe, Pu Yu, George Houlachi, Xuewen Tang

"Impedance measurements were used to investigate the electrochemical characteristics of acidic zinc sulphate electrolytes containing Sb3+, gelatin and their mixtures. The data were correlated with cyclic voltammetry curves made using synthetic as well as industrial electrolytes. The cyclic voltammetry results were similar to those obtained in previous studies in that antimony caused a depolarizing effect while gelatin gave an increase in the potential for zinc nucleation on an aluminum substrate.The electrochemical impedance spectroscopy (ElS) evaluations were conducted on electrodeposited zinc at three overpotential values. The potentials were chosen to represent various current density regions in the zinc polarization curves. The antimony and gelatin gave characteristic impedance plots which correlated with expected behavior, particularly current efficiency. Both antimony and glue appear to modify the intermediate zinc reaction sequence, but in different ways. The data strongly suggest that film formation and stability are major factors in the zinc ion reduction mechanism.IntroductionThe zinc electrodeposition process is sensitive to the presence of a variety of organic and inorganic chemical species in the electrolyte [I]. Such components can produce either beneficial or harmful effects, depending on their relative concentrations and electrochemical behavior. Extensive investigations have been made to gain a better understanding of the changes occurring during zinc deposition in the presence of such additives. Techniques employed include microscopy, x-ray diffraction, dynamic voitammetry, current imd energy efficiency studies [2-5]. Ultimately, the objectives are to identify the factors which most affect the efficiency of the process and to provide a means to effectively control them.One of the most harmful impurities is antimony, which can be detrimental when present at concentrations as low as 10 to 20 parts per billion. Dramatic changes in zinc polarization behavior, deposition structure and current efficiency have been observed with antimony in the electrolyte. Antimony appears to lower the hydrogen overpotential by hydride formation or a similar catalytic mechanism, which allows an increase in localized corrosion and zinc dissolution [6-8]."

Jan 1, 1997

Many studies have been conducted over the past 3 decades on the leaching of gold in solutions containing thiosulfate, ammonia and copper. However, most of these studies have been carried out using ore samples, with very few fundamental studies of this system being attempted. The majority of the published studies have failed to acknowledge the undesirable side reaction between copper(H) and thiosulfate, let alone account for its effect. The fact that the solution chemistry is constantly changing makes it very difficult to perform a fundamental study of gold leaching. With the advent of the rotating electrochemical quartz crystal microbalance (REQCM), such fundamental studies are possible as this instrument measures mass in real time. This has allowed leach kinetics to be measured in a matter of minutes and hence at essentially constant solution conditions; The present paper highlights that a sufficient concentration of copper(II) and ammonia are required in order to achieve appreciable gold leach rates. However, the use of air (oxygen) to maintain the copper(Il) concentration catalyses the undesirable copper(II) reaction with thiosulfate. The presence of ammonium ions is shown to have an effect on this undesirable reaction as well as on the gold leaching ?reaction. Preliminary electrochemical studies into .gold electrowinning using the REQCM show that gold(I) thiosulfate cannot be readily reduced to metallic gold in the potential region at which cementation usually occurs. However, it is well known that gold cementation onto copper occurs rapidly. The current study addresses this discrepancy by studying the effect that copper and silver have on the reduction of gold thiosulfate. It has been found that the presence of both silver and copper enhance gold deposition, particularly at low over potentials. While this is beneficial in cementation, the presence of copper and silver in solution has been found to cause passivation of the cathode surface during electrowinning at 'higher overpotentials.

Jan 1, 1998

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 T. Alboussiere, O. Paireau

"We have designed an experiment to simulate natural convection in a direct-chill aluminium ingot. In this experiment we induce natural convection within a hemisphere filled with liquid-metal (mercury). The device consists of a copper hemispherical bowl closed by a copper plate. The top is maintained at superheat temperature while the boundary is cooled. While the temperature measurements were found using thermocouples, the velocities were obtained using an original technical procedure that relies on MHD properties. By applying a steady local magnetic field, we measure the velocity. The distribution of temperature and velocity can be separated into a thermally stratified core bounded by thermal wall jets. These wall jets greatly influence the degree of macrosegregation in ingots.1. Natural Convection in Aluminium CastingIt is well known that the quality of the final product in aluminium casting depends on the movements within the liquid metal such as forced or thermogravitational convection. Strong buoyancy-driven flows are known to occur in the liquid metal pool of an aluminium ingot caster. These flows have a significant influence on the metallurgical structure of the ingot through the redistribution of heat, fragmented dendrites and segregated material within the pool. Macrosegregation mechanisms depend on favourable temperature and flow distributions in the sump, and these factors will determine the pattern and degree of macrosegregation. Moreover, for many years, the importance of thermally-driven natural convection in casting has been underlined (Cole & Bolling, 1965). In this way, a precise determination of the velocity and temperature fields is required in order to improve understanding of the macrosegregation mechanisms. That is precisely the aim of this paper, which provides experimental data of the flow and the temperature distributions in a natural convection experiment. We intend, with this laboratory experiment, to determine accurately the velocity field, particularly within the thermal boundary layer where the effects of the flows may have an important role in the transport of crystals."

Jan 1, 1999

By Sijun Li, Bingyu Zhang, Haitao Zhou, Zhendong Zhang, Guofei Si, Xianghua Liu

"Hot compression test of Nb microalloyed coiled tubing steel is performed on Gleeble3500 at 1123K—1373K and strain rate from 0.001 to 5s-1. It is found that flow softening occurs and the flow curves exhibit a peak with a characteristic of dynamic recrystallization (DRX) and change with temperature and strain rate significantly. The peak stress and peak strain are dependent on the Zener-Hollomon relationship with activation energy of 390 KJ/mol. On the basis of Avrami equation and the Zener-Hollomon parameter, it is obtained that the dynamic recrystallization kinetics equation with which the calculated and measured recrystallization fraction is very close. On the results of hot compression test, the Nb microalloyed coiled tubing steel is rolled by Thermo-Mechanical-Control-Processing (TMCP), and it is obtained that the yield strength and tensile strength of Nb microalloyed coiled tubing steel are 565MPa and 685MPa respectively, and the elongation percentage is 30.1%.IntroductionCoiled tubing is widely used in oil field for well logging, well completion, drilling, work over and other operation in various fields to solve a number of conventional operating techniques problem which are difficult resolved, and it plays a more and more important part in exploration and production at oil field. [1] It will improve the efficiency of exploration and exploitation, studying, developing and using coiled tubing technology. Therefore, the development of domestic coiled tubing materials and manufacturing technology are great significance. It is well known that Coiled tubing has relatively poor working conditions and complex force state. So, the coiled tubing needs satisfier a kind of high strength, high plasticity, and corrosion resistant under complex oil gas condition. As the coiled tubing technology developed, the level of the coiled tubing steel is from CT55 originally to CT90 and CT100, and the corresponding tensile strength is 483MPa-758MPa. [2, 3]"

Jan 1, 2012

By Shirley Cosin, Guillermo R. Martín-Cortés, Francisco R. Valenzuela-Díaz, Jorge E. Di Rito, Valquiria F. J. Kozievitch

"A procedure that is being studied as a potential method for correct disposal of industrial wastes by incorporation on common clay bodies in the fabrication of structural ceramic products as bricks, blocks and roof tiles. The objective of this paper is to present the results obtained with mixtures of unburned sanitary ware wastes with a common clay from Jundiai, São Paulo, Brazil. Preliminary tests of incorporation (1,0% to 30,0% in weight) were made with hand formed spherical test bodies. With the proportion that presented spheres with the higher compression strength after drying and after firing (950°C) prismatic samples were extruded. Based on the ceramic properties of those mixtures an industrial test was performed. Six hundred hallow blocks containing 30% waste were fabricated and presented ceramic properties similar to those without incorporation. Introduction The sanitary ware segment has a very great prominence in South America, placing Brazil as one of the greater producers of the world.. Inside the country, the city of Jundiai, in the State of São Paulo is the greater producer region of this ware. Great part of the material is destined to exportation and daily it is produced high number parts. High exportation requirements make that the amount of powder waste rejects reach astronomical volumes. Until the moment too small part of that material it is re-taken with advantage, because in the own segment, there is not an economic viability, by the fact of the exigencies concerning the quality of the final product [1]. If from one side it exists that material that at the moment is deposited in landfills, or stored at the patio’s factories, from the other side the exigency of adopting exploitation rules, recycling and obedience to Laws relative to the environment as ABNT 10400, therefore it is a material that if well studied, it will certainty have a noble destiny [1]."

Jan 1, 2008

By Shadia J. Ikhmayies

"Nanocrystalline fluorine-doped tin oxide, SnO2:F, thin films were prepared by the spray pyrolysis (SP) technique on glass substrates. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray dispersive spectroscopy EDAX and transmittance measurements. X-ray diffraction patterns revealed the nanocrystalline nature of the films where the grain size was estimated based on the Sherrer formula. SEM micrographs showed that the films are uniform and totally covered with the material and they confirmed the nanocrystalline nature of the films. The absorbance was deduced from the transmittance measurements, and its first derivative was used to estimate the optical bandgap energy. Bandgaps larger than the bandgap of the bulk SnO2iF were obtained, indicating the presence of quantum dots. The hyperbolic band model was used to estimate the radii of the nanocrystallites. A comparison between the results of the different methods was performed.IntroductionTin oxide, SnO2, thin films are n-type semiconducting, transparent materials, which have numerous important applications in optical-electronic device technology. The optical transparency of SnO2, together with its chemical and mechanical stability, makes SnO2 films suitable for many other applications, such as transparent conductive coatings, gas sensors and heteroj unction solar cells [1]. In particular, SnO2 thin films have drawn much interest because of their potential application and integration with microsensor devices. Considerable attention has recently been focused on the development of solid state gas sensors based on thin films with a crystallite size smaller than the Debye length of the material, which show increased gas sensitivity and short response times [2]. In many of these applications, a doped SnO2 film is used as an active layer. Among the various dopants, fluorine is often preferred, because fluorine doping results in films with high transparency and good conductivity [1]."

Jan 1, 2012

By G. P. Swayn

Recycling of dusts produced in a flash furnace by direct injection provides the opportunity to reduce recycle loads to the reaction shaft, lower fuel requirements and possibly increase metal recovery to products. Ausmelt has provided an Ausmelt lance system for injecting dusts collected from the waste heat boiler and electrostatic precipitator units, directly into the slag melt. This has been installed and operated in the Kalgoorlie Nickel Smelter with systems for feeding dust, for firing with oil and air, and for raising and lowering the lance. Modelling and testwork development of dust injection, results of commercial trials and design considerations for further opportunities of the Ausmelt lance system, are discussed.

Jan 1, 1994

By S. V. Ketov, V. P. Menushenkov, V. S. Shubakov

"The glass samples were obtained by melting of the oxides mixture SrO-Fe2O3-B2O3(Al2O3) at 1200-1250°C with subsequent quenching of the melt on quickly rotating steel roller. Submicronsized Sr(Fe,Al)12O19 particles were formed in glass-ceramic matrix during the crystallization aging of glass. The aging temperature Tag varied in the range 650-950°C. The submicron-sized hexaferrite powder was obtained by removing of the matrix phases using etching. The samples were characterized by X-ray diffraction, scamiing electron microscopy and magnetization measurements. The glass-ceramic material exhibits very high coercivity value up to 10 kOe. The samples of magnets were obtained by pressing of the hexaferrite powder at RT and subsequent aging in the range 900-1200°C. The aged samples exhibit coercivity value up to 8 kOe.IntroductionStrontium M-type hexaferrites have been widely used in technology and industry mainly for production of permanent magnets owing to their appropriate magnetic properties, chemical stability and low cost [1,2]. The SrFe12019-based compounds are characterized by high magnetocrystalline anisotropy and single easy magnetization axis. The highest coercivity is received for monodomain, defect-free single crystal particles with size D - 100 mn. Finely grained strontium hexaferrite prepared by chemical methods such as sol-gel pyrolysis and oxide glass crystallization exhibits high coercivity up to 6-8 kOe [3-5]. Owing to the partial substitution of Al for Fe in the strontium hexaferrite leading to the increase in the magnetic anisotropy field Ha=2Ki/M,, the increase in the coercivity may be received [6]. The notable results were achieved using the SrO-Fe2O3-AlzO3-B2O3 glass crystallization and formation of perfect submicron crystals of alumina-doped hexaferrite [ 6, 7]. The coercive force of glassceramics reached values of up to 10 kOe. Hexaferrite particles are well faceted and have the shape ofhexagonal bipyramids with truncated vertexes [7].In the present paper, we report results of our investigation into the SrO-Fe2O3-B2O3(Al2O3) glass crystallization, hexaferrite powders and permanent magnets, which were prepared by pressing submicron-sized hexaferrite powders at RT and subsequent sintering at 900-1200°C."

Jan 1, 2012

By David G. Dixon, Ahmad Ghahremaninezhad, Edouard Asselin

"In this study pertaining to the electrochemistry of chalcopyrite, the active/passive behavior of a chalcopyrite electrode in 0.5M sulfuric acid solution was investigated. Potentiostatic and potentiodynamic polarization and multi-cyclic voltanunetry were conducted to analyze the electrodissolution parameters of the electrode.The potentiodynamic and potentiostatic polarizations of chalcopyrite revealed the formation of a passive film on the surface of chalcopyrite. From the potentiostatic study in the passive potential region, a decrease in the dissolution current density by increasing the potential was observed. From this, it was concluded that the passive film is an n-type semiconductor and cation interstitial defects or anion vacancies are the charge carriers. From multi-cyclic voltammetry studies, four cathodic peaks at - 0.37, 0.30, -0.10 and-0.20 YsHE were detected on the surface of a passivated chalcopyrite electrode. The cathodic peaks at 0.37 and 0.30 V were connected to ferric to ferrous reduction and copper sulfide formation, respectively. The peaks at -0.10 and - 0.20 were related to chalcopyrite reduction. The products of the chalcopyrite reduction reactions were suggested to be Cu2S, Cu9fesS16 and Cu5feS4 and evolution of hydrogen sulfide gas (H2S).IntroductionChalcopyrite is the most abundant copper bearing mineral in the world and its dissolution behavior represents the most important technological consideration in the hydrometallurgical extraction of copper [I]. Since the current pyrometallurgical methods for copper extraction from chalcopyrite have environmental issues, many studies have considered the leaching and dissolution of CuFeS2 in different aqueous media [2-5]. The main problem associated with leaching processes is the slow dissolution rate of the mineral [6]. During the dissolution process, increasing the potential of the chalcopyrite in the anodic direction will cause the formation of surface layers which hinder the dissolution rate of the mineral [7]. The precise composition of the layers is in dispute. Previous studies have concluded that these layers could be sulfur [8-9], precipitated iron compounds [8], a solid electrolyte interphase (SEI) - which slows the rate of electron transfer- [10], a metal deficient sulfide [ll], or polysulfidic in nature [12-13]. In order to increase the leaching kinetics of chalcopyrite, the characterization of the layers formed during dissolution is essential and electrochemical methods are important to this end. Studies by Biegler [14] show nucleation and growth of a thin two-dimensional sulfide phase on the surface of chalcopyrite during the exposure of a polished sample in HzS04 solution or air. More studies by Biegler and Swift [15] have shown evidence for nucleation and growth of a 3-dimensional phase at low anodic potentials (around 200 mV vs. OCP). The current-time behavior of the dissolution process in this potential area has the characteristics of expansion and overlap of localized dissolution centers."

Jan 1, 2012

By Biswadeep Saha, Meenakshisundaram Ramanathan, Chai Ren, Sivaraman Guruswamy

"Fe-Ga alloys have a large low-field magnetostriction and these alloys are attractive candidates in energy conversion and harvesting applications. Small additions of W also increase the magnetostriction of Fe. In this paper changes in magnetostriction by W substitution for Ga in various Fe-x at.% Ga alloys are presented. Fe-Ga-W single crystals were grown using vertical Bridgman Growth technique. [001]-orientated single crystal samples were prepared with faces within 1 degree off <100> orientation. The samples were annealed at 1150 °C in the alpha-phase region and water quenched. The magnetostriction coefficient (3/2)A-100 measurements were made on these Fe-Ga-W single crystals. The result on the effects of W substitution and annealing on the magnetostrictive behavior of these alloys are discussed.*Support of this work by NSF-DMR under the award DMR-0854166 is gratefully acknowledged.IntroductionMagnetostrictive materials changes their dimension exhibit reversible strains and changes in elastic properties in the presence of an applied magnetic field or the reciprocal effect of changes in the magnetic properties with the application of stress [IJ and are very important in sensor, actuator device, linear motor, magnetomechanical devices, microelectro- mechanical devices, active vibration dampening devices application areas. The discovery of an order of magnitude enhancement in the magnetostriction of Fe with Ga addition coupled with low saturation magnetic fields, and excellent mechanical properties opened up the possibility of obtaining larger magnetostriction values in other low-cost ductile a-Fe phase based alloys with alloying additives that are less expensive than rareearths such as Tb and Dy [2·4l_ The magnetostriction values observed in Fe-Ga single crystals are sensitive to thermal history and composition. The formation of second short range ordering phases and local defects inside crystal structure can also cause a dramatic change to this alloy's magnetostriction behavior [5-9l_"

Jan 1, 2012

By Kikuo Okuyama, I. Wuled Lenggoro, Manabu Shimada

"Aerosol processing of materials such as (i) gas-to-particle conversion process (e.g., Chemical Vapor Deposition (CVD) method) and (ii) liquid (or droplet)-to-particle conversion process (e.g., spray pyrolysis) has become of major interest to produce novel submicron- or nanometer-sized particulate material used in electronic and chemical industries. After reviewing recent theoretical and experimental researches on the evaluation of properties and morphology of fine particles by the CVD and spray pyrolysis methods, the importance of the process engineering approach· for aerosol processing of materials and the use of advanced aerosol measurement technology have been pointed out.IntroductionMaterial synthesis via aerosol processing offers a route to producing nanometer-sized and submicrometer-sized particles of high purity with specifically tailored chemical and physical properties. Especially, single nanometer-sized particles (nanoparticle materials) are considered to play an important role in the synthesis of nanostructured materials as well as in nanotechnology in 21st century due to their quantum effect and so on.However, the transformation of gaseous or liquid precursors to the final functional particulate matters consists of various complex chemical and physical processes. In order to control the size distribution and morphology of produced particles, it is important to analyze and model various phenomena, such as gas-phase or liquid-phase chemical reaction, nucleation, condensation, agglomeration and sintering that occur simultaneously in aerosol material processing. By introducing the Aerosol Science and Materials Science, the authors have been trying to model the changes in particle properties and morphology by gas-to-particle conversion and droplet-to-particle conversion processes. The authors have also been trying to obtain the experimental data on the particles properties as accurate as possible."

Jan 1, 2000

By Paul O. Malan

"The Tusc gold deposit is located along the Carlin Trend approximately 13 kilometers north of Carlin, Nevada and 2.5 kilometers northwest of the Gold Quarry mine. Tusc is one of several structurally controlled oxide gold deposits located along the Good Hope fault within the Maggie Creek subdistrict. Mining commenced in 1994 with an oxide reserve of780,000 troy ounces of gold at an average grade of 1.34 g/t Au. The Good Hope fault forms the southwestern edge of the Schroeder Mountain uplift (also known as the Carlin Window) and juxtaposes carbonate rocks of the Siluro-Devonian Roberts Mountains Formation against siliceous mudstone, siltstone, and silty limestone of the Devonian Rodeo Creek unit. Submicroscopic gold mineralization is disseminated in the Good Hope fault system and in fractured hanging wall carbonate rocks. Wallrock alteration includes silicification, deca!cification, sericitization, and late alunite replacement and veins. All Tusc ore is transported 2.5 kilometers to Gold Quarry for processing. Leach-grade ore (0.2 - 1.7 g/t gold) is placed on the oxide leach pads, and mill-grade ore(> 1.7 g/t gold) is processed through the CIL oxide mill. IntroductionThe Tusc gold deposit is located in Eureka County, Nevada, U.S. A, approximately 13 kilometers north of the town of Carlin and 2.5 kilometers northwest of the Gold Quarry mine (Fig. 1 ). Tusc is one of several open-pit, oxide, gold deposits within the Maggie Creek subdistrict of the Carlin Trend. Tusc is a structurally controlled gold deposit located along the Good Hope fault. Submicroscopic gold mineralization is disseminated in the brecciated and silicified Good Hope fault zone and along intersecting northeast and northwest striking structures."

Jan 1, 1997