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By Ludy C. Motta, Denise C. O. Nascimento, Sergio N. Monteiro

"Natural cellulose-based fibers are nowadays of growing interest for modern industrial composites. Relatively unknown fibers like piassava, curaua and gourde have shown promising behavior as reinforcement of polymeric composites. However, the hydrophilic characteristics of the natural fibers impair its adhesion to the normally hydrophobic polymeric matrix. Surface treatments can, in principle, improve this adhesion and the fiber/matrix interfacial strength. In this paper, the effect of alkali treatment of the surface of piassava (Atallea funifera) waste fibers was investigated in terms of the change in strength of epoxy composites reinforced with these waste fibers.IntroductionThe consequences of global warming and the increase in the price of petroleum are motivating the use of natural materials as substitute for energy intensive synthetic materials [1]. In particular, natural fibers obtained both, from cultivated plants such as jute, sisal, hemp and flax as well as from industrial waste such as sugar come bagasse and coir, are being considered to replace synthetic glass fibers [2,3]. These natural fibers, also known as lignocellulosic fibers, present the comparative advantages of being renewable, recyclable and biodegradable. Moreover, lignocellulosic fibers require less amount of processing energy and are neutral with respect to CO2 emission, which causes the atmospheric greenhouse effect responsible for the global warming [4]. Low cost is another important economical advantage of the natural fibers over the synthetic ones and the application of lignocellulosic is also associated with a lower wear of processing equipment and better finishing of molded components [5]. Moreover, for some fibers, properties such as the mechanical strength and impact resistance can be superiors to the corresponding properties of synthetic glass fiber [6]. The characteristics and properties of several lignocellulosic fibers are, nowadays being extensively discussed in the literature. It is beyond the scope of this work to comment on the hundreds of papers dealing with this subject. However, there are still less known fibers with great potential as engineering material that deserves investigation."

Jan 1, 2008

By M. S. Lee

A cold model study on the effects of various operating conditions on the dispersed-phase holdup in a liquid-liquid emulsion generated by bottom gas injection has been performed using water and kerosene. Dimensional analysis was used to correlate the holdup with the operating conditions and the sampling locations. The holdup increased with gas velocity, and decreased with axial and radial distances. The radial distribution of holdup follows a Gaussian function. The holdup increased with increasing ratio of the heavy phase to light phase volumes and decreased with the total height of the heavy phase. The combined effects of various operating conditions can be represented by the Froude number. The variation of the holdup within the plume was correlated by a single equation involving a set of dimensionless numbers.

Jan 1, 1995

By S. Aguayo-Salinas, J. L. Valenzuela-García, A. L. Leal-Cruz, M. I. Pech-Canul, M. T. Certucha-Barragán

"The aim of this research was to carry out a comparative and systematic study of the degradation of cyanide by hybrid natural/biodegradation and biodegradation methods using a mixture of Pseudomonas sp and Bacillus megaterium native bacteria. Bioreactors consist of filled columns with contaminated ore containing 100 ppm of total cyanide. In the biodegradation tests a mixture of bacteria was inoculated into the biodegrading solution. Results of cyanide degradation show a similar asymptotic behavior in both the hybrid (opened system) and biodegradation (closed system) methods; however, for the same period of time (72 h) the permissible maximum levels (1-2 ppm of cyanide) are only attained in the closed system. While in the closed system the cyanide levels are reduced from 100 to 1.5 ppm, in the open system, cyanide decreases from 100 to 2.4 ppm.IntroductionOne of the most important tasks of mining industry is the treatment of the wastes generated in mining operations. Accordingly, industrial waste waters and ores represent a complex problem and a great challenge. In addition to ethic and communitarian considerations, there are laws that prohibit or regulate the contamination of water and air. Moreover, they establish that the restoration of wastes must be considered as a necessary operation cost [1]. Currently this important problem is being addressed by the mining and metallurgical industries using different approaches; mainly they are focusing on the treatment of waste waters and ores generated by the leaching process in which cyanide is used as a leaching agent for the recovery of precious metals as gold and silver. Cyanides have toxic characteristics and thus negatively impact the environment when they are discharged to the ground without previous treatment. While there are some processes in current use there are others that have only been proposed and that allow cyanide degradation, transformation to less toxic compounds and/or the complete elimination of cyanide. The second group includes a variety of techniques that use natural, chemical and biological treatments. Natural treatments consist of the passive abandoning of the heap and of its washing with water. Since these processes are slow and generate great volumes of water partially contaminated, then other alternatives should be considered."

Jan 1, 2008

By Norbert Hort, Karl Ulrich Kainer, Carsten Blawert, Daniel Fechner

"With the development of new heat resistant magnesium alloys, the automotive industry has introduced several parts to the drive train. The rising number of large magnesium components will result in a higher quantity of automotive post consumer scrap and the changing legislation will force car manufacturers to take magnesium recycling into consideration. So far post consumer scrap has not been used for magnesium alloy production. Quite a reasonable amount of automotive scrap is likely to end up in a mixed light metal shredder fraction. The separation of mixed magnesium scrap according to several alloys is complex. Therefore secondary magnesium alloys made from blended post consumer scrap would be useful. For this work a matrix of potential recycling alloys was prepared by chill casting and high pressure die casting. The materials were investigated for their microstructure, mechanical properties, heat resistance and corrosion properties. The results will be presented in this paper.IntroductionWithin the last ten to fifteen years several heavy magnesium parts have been assembled in passenger cars, such as gear box housings and crank cases [1, 2]. Reasons are the lately developed new heat resistant alloys and the increasing responsibility of automotive manufacturers to reduce the vehicles weight and thereby CO2 emissions. The latter is pushed by international legislation [3, 4]. The rising quantity of magnesium in automobiles will result in an increasing amount of so called post consumer scrap at the end of the vehicles life.So far magnesium recycling was done only for clean scrap that is free from impurities, contaminations and sorted according to a chemical composition or a single alloy respectively [5- 15]. The latter is also called class 1 scrap and mainly consists of sprues and runners from magnesium die casters [15, 16]. For the upcoming automotive post consumer scrap the materials quality strongly depends on the way end of life vehicles are treated. By proper dismantling of old cars, the bigger magnesium components could be collected and possibly treated similar to class 1 scrap [15]. Up to date automotive manufacturers have no uniform recycling system for end of live vehicles. Most probably a considerable quantity of old cars will be shredded. The resulting light metal shredder fraction will contain aluminium and magnesium scrap, both from several alloys. A separation of mixed magnesium and aluminium scrap is feasible according to [17]. Other authors claimed that the grade of separation of magnesium from aluminium is still not sufficient for a proper industrial recycling process of magnesium post consumer scrap [15, 16]. If an automatic sorting is possible it will probably be very expensive [18]. Therefore, so far the main use of post consumer scrap has been the steel desulphurisation and aluminium production [15]. The use of post consumer scrap for magnesium alloy production has been considered already by [15] and [16] but some problems have to be approached."

Jan 1, 2008

By Moo Eob Choi

The reduction of iron oxide particles by hydrogen is one of the most widely investigated gas-solid reactions. The search for new methods for producing iron by the direct reduction of iron oxide has resulted in a large number of exhaustive studies of the various aspects of this reaction. However, previous studies have largely been done with either pellets or lump ores. Little has been published on the hydrogen reduction of very fine concentrate particles smaller than 37 µm (-400 mesh). The kinetics of hydrogen reduction of fine iron oxide concentrates were investigated in the temperature range of 900 - 1300°C.

Jan 1, 2006

By Wantae Kim, Furnia Saito, Qiwu Zhang

"A novel mechanochemical processing technique for the preparation of zeolites from kaolinite in NaOH solution was investigated. Dry and wet mechanochemical treatments combined by subsequent moderate heat treatment could accelerate the synthetic reaction for zeolites from kaolinite. This stimulating process produced zeolite-A and zeolite-X from activated kaolinite at extremely lower reaction temperature than conventionally applied for zeolites production. Conversion to zeolite-A and zeolite-X was strongly dependent on the activated state of kaolinite. Wet mechanochemical treatment modified the chemical composition of activated solids. Rapid dissolution of AIO species rather than SiO ones in the reactant solution was accelerated by wet milling together with NaOH that promoted the formation of zeolite-X of high specific surface area.IntroductionZeolites are a family of hydrated alumina-silicate minerals contains alkali and alkaline earth metals. They have a framework structure that encloses inter-connected cavities occupied by large metal cations and water molecules. Zeolites are characterized for their ability toward ion exchange and reversible dehydration. Properties of them are exploited through commercial productions of particular structural and chemical features. Zeolites are used as commercial uses for catalysis for FCC (fluidized catalytic cracking) of petroleum refining, drying reagents of gases and liquids, and selective adsorbent for pollution control [1-3]. In such purposes, artificially synthesized zeolites are employed, although natural ones are associated with hydrothermal and hot spring alteration of volcanic materials. Commercially, a hydrothermal process has been used for the preparation of zeolite synthesis. This preparation method gives zeolites of high chemical homogeneity and purity, however, this wet-chemistry-based processing is significantly influenced by reaction temperature, pH, concentration, and composition of starting substances [4]."

Jan 1, 2000

By T. Takasu

Overall productivity in copper refining is currently determined by the electrorefining process. Previous research showed that forced convection of the electrolyte improves the morphology of the copper deposit on the cathode and suppresses passivation of the anode. In this paper, electrorefining experiments under forced convection were carried out in the presence of As, Sb and Bi impurities, both in electrolyte and in the anode, to determine the effect of the impurities on the electrorefining process. The concentrations of the impurities in the deposit increased with increasing current density without forced convection. An increase in the fluid velocity suppressed the increase in impurity concentration. These concentrations were high, especially in the initial stage of deposition without forced convection, corresponding to a decrease in the cathode potential measured during that period. This indicates that the enrichment of impurities was induced electrochemically. The reason for the decrease in cathode potential was the low concentration of copper ions on the electrode surface because of ion consumption by the electrolysis. The forced convection of the electrolyte enhanced the ionic mass transfer and thus suppressed the polarization and deposition of the impurities. The fluid motion was shown to be effective in achieving electrolysis under high current density conditions.

Jan 1, 1999

By Shantanu Chakrabarti, Khursid Alam Khan

"Globally, the use of metallic coated steel sheets in the automobile industry is increasing. The sheet should have excellent formability, weldability, paintability and corrosion resistance. Since bare cold rolled steel sheets have certain limitations, application of galvanized steel sheets is steadily expending. Galvannealed steel sheet fulfills all requirements and has become of major interest in the automobile industry.The success of Galvannealed (GA) steels in the body-in-white depends upon material design and parameters of various processes involved, like cold rolling, continuous annealing, hot dipping and galvannealing. In the present work, powdering resistance, one of the important product characteristics of GA, has been studied and a relation is established between the process parameters and the powdering value. The product obtained through optimization of the process parameters have been successfully used by major automotive producers without any powdering problem, for internal as well as external automotive applications.IntroductionThe present automotive industry demands that steel for the auto components should have excellent formability, weldability, paintability, corrosion resistance etc. In addition to this there is specific requirement for some particular components like high surface quality for skin panels. Corrosion resistance of panels is important requirment which determines the life of the particular component and brand value of the automotive. Among all the zinc based steel coating used in the automotive industry coating produced by Galvannealing process has received most attention because of its excellent weldability along with superior corrosion resistance and better paintability."

Jan 1, 2012

By Juan B. Cabezas

"The favorable characteristics and workability of plastics as a replacement of wood, lead, stainless steel, asphalt and other materials are described. Various types of plastic have proven to be the most favorable choice for handling a variety of acidic, alkaline and organic solutions, as well as pulps, chemical wastes, slurries or tailings for impoundments. The material origin of various plastics, methods of manufacturing and specifications applied to leaching solutions are discussed, including availability and costs. Examples of select plastics are considered for use as alternatives of other materials under severe environmental requirements.IntroductionHydrometallurgical processes applied to gold recovery, as well as other metals, require the use of strong solutions of alkaline, acidic or organic nature, and may also include a variety of materials with extraneous characteristics and complications for handling in storage.The technology of leaching has been in use for more than 100 years, but the applications of leaching processes in metallurgy have become more commonly used in the last 15 years. Suitable materials for the construction of containers, launders, piping, and various accessories, to be used in the handling of leach solutions or slurries, have become a serious problem. Various metals such as brass, lead, stainless steel, etc., and non metallics including wood, clays, glass, rubber, ooncrete, tars or miscellaneous compounds have been tried in the past with serious limitations in workability and resistance to wear and corrosion. For example, the use of metallic, wooden or glass piping systems would require extraordinary shop maintenance to keep such systems in operation"

Jan 1, 1997

By John L. Hostetler

GALFAN, the Zn-5% Al-mischmetal hot-dip galvanizing alloy is coated onto steel sheet, wire, and tube using high-speed continuous galvanizing lines. Factors critical to producing high quality GALFAN are reviewed, The relationship between minimum mischmetal content in the GALFAN alloy and furnace dewpoint will be described. The relationship between peak annealing temperature and furnace dewpoint will also be shown. Typical suategies for operating multi-purpose hot-dip galvanizing lines including GALFAN will be described. A recent development has allowed preparation of steel smp for GALFAN coating using aqueous fluxes rather than high temperature annealing. This allows production of GALFAN-coated smp without over-ageing of the steel, and allows high steel strengths and hardnesses to be obtained. The principles of this process will be described.

Jan 1, 1992

By Tobias Pröll, Bernhard Kronberger, Joachim Rohovec, Werner Hölt, Hermann Hofbauer

"As this is only a first draft, more precise explanations as well as detailed schemes, figures and plots will be included in the final draft. The description og the 100 kW test rig will also be mor detailed as construction is ongoing and will be finished during the summer. Furthermore simulations are to be finished shortly; so details on combustibles and gas concentrations will also be included in the final draft.AbstractOxyFuel combustion is a key technology for the efficient separation of CO2 from fuel combus¬tion (especially coal). Since coal plays a minor role in the Austrian energy mix the application of OxyFuel towards other fuels (biomass, waste fuels) is interesting to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alter¬native fuels is also interesting from a strategic point of view in order to generate knowledge for operation of capture ready cofiring and waste/sludge-incineration plants. OxyFuel uses a synthetic mixture of 02 and recycled exhaust gas where the 02 content may vary. This supplementary degree of freedom allows improved operation especially for low calorific fuels. Heavy fuel oil addition for low calorific combustibles can be omitted when using OxyFuel combustion. Application of alternative fuels (wood, waste wood, municipal waste, sewage sludge) in a 100-kW CFB plant is investigated in combination with process simulation.IntroductionOxyFuel combustion is discussed as one of the key technologies for the efficient separation of CO2 from combustion of fossil fuels (especially coal). Since coal plays only a minor role as primary energy source in Austria, the broadening of the scope towards OxyFuel of other fuels like biomass or waste fuels is necessary to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alternative fuels besides the large coal-oriented projects is interesting also from the strategic point of view. The presented project aims at the generation of knowledge in order to design and operate capture ready cofiring and waste/sludge incineration plants."

Jan 1, 2008

By R. Ghisleni, R. E. G. Bohrer, L. Radtke, R. M. C. Santana

"The major source of environmental pollution in urban areas is the transport sector and its impact on human health and the greenhouse is preoccupying. In many works of literature is monitored the pollutants in urban cities, however in specific areas such as universities, they are scarce. Therefore, the aim of this work is to monitorate the gaseous pollutans in a bus terminal at Santa Cruz do Sul University-UNISC and to develop a control framework of the air quality. Six points were selected for monitoring, being one of them inside a bus. The monitoring of CO, HC and CO2 were carried out on arrival and departure of the bus. Preliminary results conducted in a day of spring showed that the most critical condition was during the night shift, where the concentration of CO (200 ppm) was the highest, caused by the vehicles increase, due to the larger number of students.IntroductionThe first major global assessment of climate change science in six years has concluded that changes in the atmosphere, the oceans and glaciers and ice caps show unequivocally that the world is warming. The report released on February 2, 2007, the first of four volumes to be released this year by the IPCC, also confirms that the marked increase in atmospheric concentrations of greenhouse gases is the result of human activities.The transport sector has become by far major source of environmental pollution in urban areas. The continual traffic growth has raised concerns over the impact of traffic emissions on human health and urban environmental quality, and has fuelled the demand for a coherent regulatory framework for the management of traffic, air quality and emission at urban level, as well as at regional and national scales.In Greater Metropolitan São Paulo, Brazil, fossil fuel combustion in the transportation system is a major cause of outdoor air pollution (Miraglia&El Kouri, 2007). In China several studies on gaseous emissions are being conducted by F. Costabile&Alegrini, (2007), developed a study on the pollutants in the city of Beijing suggesting methods for the control of pollution.The results obtained from the estimation of the atmospheric pollutants emitted monthly in Campo Grande/MS, Brazil, by buses and minibuses, which employ diesel, biodiesel or natural gas as fuels showed that the substitution of diesel by biodiesel would diminish the emissions of pollutants (Kozerski&Hess, 2006)."

Jan 1, 2008

By J. K. Brimacombe

"Nearly all the easy things have been investigated in injection metallurgy. Water models have been used exhaustively to study mixing, gas distribution and flow in submerged jets. Mathematical models have been developed with their restrictive boundary conditions to quantify submerged gas jet behavior. While being valuable tools to our understanding of injection metallurgy, there is an obliqueness to their application. What we need now are measurements and modelling on the actual systems, hot and unfriendly, where gas meets liquid at temperatures above l000°C. This is where the challenge lies.AN APPRECIATONThere are those who follow the trail and there are those few who blaze new trails in search of novel concepts and processes. With his restless, inventive mind, Howard Womer is a trail blazer without doubt. Decades ago, he was a pioneer in the pursuit of continuous steelmaking with the WORCRA Process and, today, he is developing new processes for the treatment of waste. He is not only an inventor but has been a professor at the University of Melbourne and was the first Director of Research at BHP. He has influenced the lives of many people, including myself; with his achievements and humanity. Therefore it is most fitting that this symposium should be held in honour of Howard Womer, a luminary in the metallurgical world for over half a century.BACKGROUNDGas injection has been an integral part of pyrometallurgical processes since the early days of Bessemer, then of Pierce and Smith. Today, of course, one cannot imagine pyrometallurgical processes without submerged gas injection to effect reactions for metal extraction and refining, to provide mixing and to inject solids into molten metal, slag or matte. Spurred on by new developments like tonnage oxygen and argon production, the Savard-Lee concentric tuyere and porous plugs, new steelmaking processes have emerged; and now solids injection is changing copper extraction processes. The ingenuity of the extractive metallurgists who drove these developments is inspiring for they have applied gas injection to transform pyrometallurgical processes. Humankind has been the beneficiary.' Today these processes are safer, more efficient, cost effective, less energy intensive and more environmentally friendly."

Jan 1, 1996

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

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

Jan 1, 2011

By J. P. R. deVilliers

A procedure is described whereby gold-containing calcined concentrates and leach residues from refractory gold ores are smelted with carbon to form a small amount of metal. The gold is liberated upon smelting, and is collected in the molten metallic phase, which is easily separable from the slag. The metallic phase consists of approximately 1 to 15 per cent (by mass) of the material after smelting, and the gold content is generally upgraded by a factor of greater than 6 compared with that of the original roasted material. Recoveries better than 95% have routinely been achieved. The quenched metal contains predominant Fe-Ni alloy, as well as minor Fe sulphides and Cu-Fe sulphides. Trace amounts of Fe-Ni arsenide and Au-Cu alloy are also present. The gold content of the metallic phase can be increased further by oxidation of the hot metal in the presence of silica or slag. This will reduce the amount of metal, and will concentrate the gold in a smaller volume. The metallic phase can then be treated hydrometallurgically to recover the nickel and the gold.

Jan 1, 1989

By Xiaohui Li, Lianyun Liu, Hongmin Zhu, Chunfang Zi, Kai Huang, Hongjie Li

"The dissolution kinetics of steelmaking slag in pure water was studied, and the relative influential factors were investigated. The dissolution behavior of slag particles in water was well described by Noyes–Whitney equation, and for this kind of sparingly soluble rigid mineral this simple model was extensively applicable to describe their dissolution process. Experimental data were also obtained to confirm the significant promotion effect on the growth of some algae.1 . IntroductionIt has been found that the population of phytoplankton distributed in the ocean was significantly related to the concentration of some elements [1]. For example, silicon and iron were very low in the high-nitrate low-chlorophyll (HNLC) areas, which was the main factor limiting phytoplankton and other biomass growth in these open ocean surface water [7]. The silicon and iron-rich test also confirmed that the supply of these elements had the direct effect on the growth of phytoplankton processes at HNLC areas [2-8]. So in order to promote the growth of phytoplankton in these ocean areas, providing some of these elements into these ocean areas is a natural idea for choice. Steelmaking slag is a good resource for consideration because it usually contains silicon, iron, phosphorus and other elements that are necessary for the growth of phytoplankton [8-10].Haraguchi has proposed the following idea that [5-6], if steelmaking slag can be spread to the open ocean, the trace components like silicate, iron and phosphate as the indispensable nutrients for the growth of phytoplankton, will be leached into the sea water, not only promoting the growth of phytoplankton, but also making good use of these huge amount of steelmaking slag produced every year. Based on this idea, they have carried out studies in recent years and they found that silicon and iron in the slag could be extracted into seawater effectively and play a positive role in the growth process of many algae. About the dissolution of the steelmaking slag, the Japanese scholars' research work mainly focused on the thermodynamic analysis of its dissolution possibility, and in the process of dissolution they tried to adjust the pH value of the seawater by continuously adding hydrochloric acid, which was deviated from the natural conditions of dissolution, and so the laws drawn under these special conditions can not give the identical guide to the practical application. Therefore, it is quite necessary to investigate the dissolution behavior of the steelmaking slag in the seawater at the normal pH range without adjustment to simulate the dissolution possibility under the natural conditions. In the present study, the silicon extraction behavior from the steelmaking slag was investigated and the dissolution kinetics in this process was also discussed in detail. Further studies were also performed here to evaluate the promotion of steelmaking slag on the growth of algae."

Jan 1, 2011

By Jian Li, J. Miles, P. Liu, W. Cook, W. Zheng, Alvin Qian

"High temperature corrosion resistance is one of the key challenges in water-cooled nuclear reactor material development. Iron based materials with low Cr content exhibits superior high temperature mechanical properties. However, due to the relatively low Cr content, their corrosion resistances under supercritical water (SCW) conditions are generally poor. High-Cr alloys, despite their much improved corrosion resistance, often suffer from embitterment due to the precipitation of sigma phase in the microstructure. In this study, corrosion resistance of an in-house produced high Cr steel (25%Cr) showed much better corrosion resistance compared to that of low Cr alloy (14%Cr). This high-Cr steel can potentially be used as a corrosion-resistant coating for structural materials in sew applications.INTRODUCTIONThe supercritical water-cooled reactor (SCWR) concept is one of the promising designs for the next generation nuclear reactor, in which the water coolant is designed to be at about 625°C and 25 MPa at the outlet of the reactor core. Under these relatively high-temperature and high-pressure conditions, the cooling water is at supercritical state. High-temperature mechanical properties, corrosion resistance and radiation damage are some of the key challenges. At present, no single commercial material can meet all the requirements of the severe SCWR in-core conditions. Canada supports research in several key areas of SCWR development, including materials selection. A major focus is on materials development, selection and evaluation for both in-core and out-of-core components.Allen et. al. [1] carried out a comprehensive study on the SCW corrosion resistance up to 600 °C on commercially available high temperature materials including Ni-based super alloys, various types of stainless steels and ferritic/matensitic steels. They concluded that ferritic steels develop a relatively thick but mechanically stable oxide layer, while austenitic alloys develop a thinner oxide layer that has been found to spall in some cases. Of the three types of alloys examined, the Ni-based alloys exhibited the lowest oxide thickness, however pitting was observed in the vicinity of intermetallic precipitates."

Jan 1, 2011

By Kevin L. Purdy

The Process Technology Center of Phelps Dodge Mining Company (PDMC) .operates several test facilities in support of PDMC's hydrometallurgical operations. Installations for small leach columns, 15 cm. to 60 cm. (6 in. to 24 in.) in diameter, and large leach columns, 1.8 m. (6 ft.) in diameter, are complemented by a test facility for SX/EW operations. The history of and reasons for the development of these facilities: are described and original standard equipment is discussed. A primary goal in constructing these facilities was achieving a high degree of flexibility to allow for testing of new equipment and new leaching and SX/EW technologies as they are developed. Along with this challenge, construction of a filly integrated SX/EW test facility on a small scale brought its own set of challenges.

Jan 1, 1999

By Lei Zhang, Shining Chen, Lina Wang, Pu Liu, Benquan Fu, Jiannyang Hwang

A PFS(polymeric ferric sulfate) coagulation-photocatalytic oxidation technology was used for advanced treatment of coking wastewater from secondary biological treatment. Effects of some key factors on TOC removal rate were investigated, and the results were compared with those of the common photocatalytic oxidation technology under the operating parameters of the photocatalytic oxidation defined. Single factor experimental results showed that TOC removal rate could reach 81%, when optimal operating conditions were as follows: TiO2 loading: 4.0g/L, irradiation time: 4h, initial pH is 5.1and PFS dosage:700mg/L. PFS coagulation and photocatalytic oxidation have synergistic effect, which is meaningful for highly efficient treatment of coking wastewater

Jan 1, 2015

By Judy Che, Steven Ceccio, Gretar Tryggvason

"A detailed understanding of drop deformation and solidification is essential for quantitative predictions of geometry and properties of parts made by ballistic particle manufacturing processes. Axisymmetric results of towers built by the deposition of multiple drops are presented. In these computations, fluid flow, heat transfer, and phase change are fully coupled throughout the drop deformation and solidification process. The solution method is based on a single set of conservation equations written for all phases simultaneously. The phase boundaries are treated as imbedded interfaces by adding the appropriate source terms to the conservation equations. A parameter study demonstrates the effect of Weber number, Peclet number, and drop deposition frequency on the final shape of the structure. Numerical results show that most successful method of building uniform towers is when two conditions are met. First, each drop solidifies at the same time in the deformation cycle. Second, the cooling rate is slow enough to allow for good adhesion between drops. The ability to predict the final shape of deposited drops will greatly reduce the amount of experimentation necessary to select the desired set parameters for any artifact.IntroductionMaterial deposition techniques based on layering small molten metal drops holds the promise to build small, coherent three-dimensional structures. In this process, numerous 20-100 µm diameter drops are deposited onto a substrate with a low impact velocity (on the order of 5 mis). Both the momentum and trajectory of each drop are controlled precisely to build up complex parts. This material layering technique differs from processes such as spray forming and splat quenching which involve high impact velocities (on the order of 100 mis) and high frequency deposition with little control over individual drop placement. This process of layering small drops can produce parts with near net shape accuracy, while spray forming produces slabs of material which must then be worked to make a usable part. The ability to computationally predict final drop shape and cooling rate has the advantage of allowing the user to select parameters to produce parts with desired shape and mechanical properties. However, the development of such predictive methods requires a thorough understanding of both drop deformation and solidification"

Jan 1, 1999