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By Jean Igor Margem., Lucas Barbosa de Souza Martins, Frederico Muylaert Margem, Sergio Neves Monteiro, Artur Camposo Pereira, Rômulo Leite Loiola

"The fibers extracted from the stem of the bamboo plant have been investigated as possible reinforcement composites due to their relatively high tensile strength. Although previous works have already been conducted about the mechanical properties, up to now a dimensional characterization of the distribution and the effect of diameter on the elastic modulus of bamboo fiber of the specimen dendrocalmus giganteus has not been performed. The aim of the present work was to statistically characterize the distribution of the diameter of a lot of bamboo fibers of that specimen. Based on this characterization, diameter intervals were set and the dependence of the Elastic Modulus (E) of theses fibers with a corresponding diameter was analyzed by the Weibull Method. The results indicated an inverse dependence, in which the highest Elastic Modulus were obtained for the thinnest fibers. Moreover, it was found that a mathematical hyperbolic relationship fit well this inverse correlation between the Elastic Modulus and the bamboo fibers diameters.IntroductionBamboo is a well known grass-type plant with a hard and stiff stem or culm that can reach, in some species, more than 10 cm in cross section diameter and stand several meters height. Owing to its low density, approximately 0.9 g/cm3, bamboo culms have been used in house construction from scaffoldings to panels. As an abundant natural resource in tropical and temperate regions, specially in Asia and South America, bamboo is also a substitute for wood and plastics in furniture and lightweight parts of automobile [1,2]. The cylindrical shape of the culm is, however, a limitation for its direct use in engineering systems. Consequently, research works have been conducted on bamboo fibers stripped off from the culm as reinforcement of polymer composites. [1-12]. According to Shin et al [3] bamboo fiber-epoxy laminates can be made into specific sizes and shapes, preserving the natural microstructural properties. These fiber composites overcome the limitation of the culm's cylindrical macrostructure. As a further advantage, Shin et al [3] indicated that cracking and bioerosion caused by insect pests is prevented."

Jan 1, 2013

By D. Mukerjee, Ramen Datta, Sanak Mishra, R. Veeraraghavan, K. L. Rohira

"Recent efforts at Steel Authority of India Limited (SAIL) has led to the successful development of atmospheric and marine corrosion resistant high tensile Thermo Mechanically Treated (TMT) bars with minimum specified yield strength of 50 kg.mm-2. These rebars are increasingly being used for a wide range of end-applications, namely, concrete reinforcement structures, bridges, flyovers, dams etc. Welding is an important processing tool for each of the above applications. In view of the importance of welding, a comprehensive evaluation of the weldability properties has been carried for the two grades of steels using Submerged Metal Arc Welding (SMAW) process; the most popularly used technique of welding of reinforcement bars (re bars).Implant tests were conducted to assess the cold cracking susceptibility of the steels. The static fatigue limit (SFL) value, determined for the atmospheric corrosion resistant (Cu-TMT) rebars under no preheat and no rebalcing conditions was found to be 63.8 kg mm-2, which was significantly higher than the Minimum Specified Yield Strength (MSYS) (50 kg.mm-2). This indicates adequate resistance to hydrogen induced cracking (HIC). On the other hand, the SFL value obtained for the marine corrosion resistant rebars (Cu-Cr TMT) under no preheat, no rebaking conditions was found to be inconsistent. Repeat of the test with fully rebaked electrodes (350°C-2h) resulted in a high SFL value (60.3 kg mm-2)_The rigidity of the structure or restraint influences the susceptibility of the weld joint to cracking. The cracking tendency increases with restraint intensity (K) of an assembly. The critical restraint intensities determined for the two steels were found to be· in excess of 1680 kg/mm.mm, indicating good welding behaviour with the following welding conditions : for Cu-TMT rebars with no preheat and no rebaking and for Cu-Cr TMT rebars with no preheat and fully baked electrodes; that is under low hydrogen levels."

Jan 1, 1998

By R. L. Miller

Oil -bearing metal sulfide sludges produced in treatment of an industrial wastewater, which includes plating wastes, have yielded to treatment by electrooxidation and hydrogen peroxide processes. The oxidation can be controlled to be mild enough to avoid decomposition of the organic phase while oxidizing the sulfides to sulfates. The pH is controlled to near neutral conditions where iron, aluminum and chromium(II1) precipitate as hydrous oxides. Other metals, such as lead and barium, may be present as sulfate precipitates with limited solubility, while metals such as nickel and cadmium would be present as complexed ions in a sulfate solution. The oxidations were found to proceed smoothly, without vigorous reaction; heat liberation was minimal.

Jan 1, 1992

By N. Mizutani, S. Harada, Z. Asaki, T. Tanabe

"The development of lead-free solders is urgent in view of environmental standpoints. In this -work the wettability of tin-bismuth- silver solders on copper was studied. Three kinds of fluxes were used. The wettability of conventional eutectic tin-lead .solder exhibited an excellent level over the other solders of tin-bismuth systems. Poor wettability of the tin-bismuth solders may be caused by the growth or dendritic copper-tin compounds at copper/solder interface, in contrast to the case of tin-lead'· solder. The wettability was improved by the addition· of silver in the solder. In this tin bismuth- silver system, silver was abnormally concentrated at the copper I solder interface even in the initial stage of contact. The wettability of the solder and the thickness of compound formed on the copper have a good correlation; the solder containing 2% silver exhibited the best wettability and the formation rate of copper-tin· compound on the copper was slowest.IntroductionSocial demand to avoid lead use in the industrial fields has been recently promoted· (1) because of the environmental protection of water resources. Especially the lead-bearing solders have been widely used in electronics and automobile products, and it is urgent to replace them with nontoxic materials (2)-(4). Thus the development of lead-free solders becomes an indispensable subject to the new generations and many works (5)(6) have already been carried out on the research and development of new solders. New lead-free solders are expected to have some requirements, for example, moderate melting temperature, proper strength and integrity, and lower prices, as compared with conventional solders. There have been already several alloy systems developed. Among ·these alloy systems, tin-bismuth binary or tin-bismuth-silver ternary alloys have great advantages such as having a wide range of soldering .temperature by controlling con:ipositions, though they have such disadvantages as ""lift-off"" (7)-(9): It is said, on the other hand, that a frequently overlooked property of solders, or one that is typically ignored by the research scientist as an ""issue"" for the manufacturing or product engineer, is wettability (10), although a ·work on the wettability has recently been published (11). In this Work, therefore, the authors selected Sn-Bi-Ag solders and focused mi the effect of Ag-addition to wettability of the solder."

Jan 1, 2000

By H. Fukuyama

The wetting behavior of single crystalline MgO by fayalite-type slag melts has been studied by the sessile drop technique incorporated with high temperature X-ray radiography. The experiments were performed under oxygen partial pressures of 10-6 and 10-4 Pa at 1473 K. Mass ratios of iron to silica, Fe/Si~, in the slag employed were 1.4 and 2.0. To investigate the interfacial reaction, experiments using high density MgO crucibles were also conducted. The reactions at the interfaces were examined by Electron Probe Microanalysis. The contact angles between the slag melts and the MgO substrates were found to be relatively low, ranging from 30 to 10 degrees. The surface tension of the slag was 0.4 N/m for a slag of Fe/Si02 = 2.0. Two phases, magnesiowiistite and olivine, were observed at the interface. Interdiffusivity in magnesiowiistite solid solution was determined as a function of iron oxide content. Phase relations between magnesiowilstite and olivine, and the growth rates of both phases, are also discussed

Jan 1, 1996

By Joel A. Huffinan

"This presentation is being given to better inform the audience of the dependability of precious metal analysis by fire assay. A brief explanation, however, of standard fire assay exploration procedures will be given. An overview of other types of analyses by fire assay will be discussed as well, and the operation of a modern day assay laboratory.IntroductionThe use of lead oxide for the fire assay process dates back to the finds in Troy II and the Cappadocian Tablets about 3,000 B.C. Some advances have been made in the basic procedures due to instrumentation and electronics, but the fusion and cupellation procedures used in fire assay remain much the same as during this period.In 1600 AD. Agricola was the first to take a scientific approach to fire assay recording methods and procedures used (Hillerbrand and Allen, 1905) [1]. Since this period, much of the recognized research into the analysis of ores and metals was carried out in the late 1800's and early 1900's prior to World War II, and again after the deregulation of precious metals. The renewed interest in precious metals mining and metallurgy are due much to advances in precious metals heap leaching in late 1970's."

Jan 1, 1999

By Debbie Marshall

Process water is an important consideration in the development of a nickel laterite project. Depending on the location of the ore body, sufficient fresh water may not be available and it may be necessary to use seawater (or saline groundwater) for ore preparation. This introduces various species, which have major effects on materials of construction and leaching chemistry. This paper summarizes batch testwork completed at the Falconbridge Technology Center. The leaching behaviour of eleven different laterite ore samples were compared using seawater and fresh water. For brevity, six of the eleven samples are reported here-the other five samples showed similar results. Each ore type was leached under identical conditions in both freshwater and seawater and the leaching chemistry compared. The batch test results were confirmed in a continuous pilot plant, and leach kinetics for the two systems were compared. Keywords: high pressure acid leaching, laterites

Jan 1, 2004

By Larry Southwick

This Peirce-Smith Converting Centennial symposium is celebrating the contributions of two men, William Peirce and E.A.C. Smith, in advancing technology allowing the copper industry to realize its full potential. However, theirs is representative of a larger story: New, simpler technology releasing the stranglehold of older, more complicated technology, new developments in vessel configuration and design finding alternate routes around dead ends in operability, advances in technique and concepts removing roadblocks of cycle time and capacity, and overall innovation opening up vast new reserves around the world to those companies willing to embrace those improvements. Our story is also one of personalities, stubborn smeltermen versus the innovators, those inside the industry versus those from outside. It is a story of an initial borrowing from the steel industry, but also Peirce and Smith, from the refining end of the copper business, taking the ideas of Baggaley from Pittsburgh’s steel and airbrake industry, who built on what Hollway, Manhès and David, Douglas, and others had done in smelter tests, further to compete with the previous primacy and closely held expertise of the copper smeltermen in Wales. These advances have been well recorded in photographs taken over the last 150 years. A number were submitted especially for this symposium. Many others were published in the mining and metallurgy press of the times. Several mining schools also retained copies of photos either taken during field trips, or donated to the school by alumni and operating companies. This presentation will provide a selection and discussion from these sources of “converters in action”, describing the various designs, operations and developments depicted. The focus here will be on the first roughly 60 years of copper converter development, from Bessemer’s days at the dawn of this new idea, up to and slightly past the time of initial adoption of Peirce and Smith’s designs.

Jan 1, 2009

By T. J. Weitz, J. E. Micheletti

"Pegasus Gold's Beal Mountain Mine is located near the Continental Divide, SW Montana. Conventional surface mining utilizes crushing, heap-leaching, carbon absorption/desorption, electrowinning and refining to produce approximately 60,000 oz gold annually. A leach pad sits at 2,300 meters (7,500 ft) elevation. Winters are long and cold with average snow accumulations ofl-2 meters; temperatures fall below minus 40'C and wind chill temperatures below 70°C. The Beal Mountain staff has developed special tools and procedures for burying drip emitter lines, and managing the heap and process solutions to allow for uninterrupted gold recovery during the winter season. Management of water balance and spring runoff is critical to the operations' success, due to mountainous terrain, high precipitation and proximity to a fishery and elk herd. The mine has an extensive network of land application disposal (LAD) and stormwater control systems to assure environmental protection and regulatory compliance.ABSTRACT ONLY"

Jan 1, 1997

By Doon Gibbs

In this talk, we review highlights of x-ray magnetic scattering studies performed during the last decade, concentrating at the beginning on experiments on the rare earth metal holmium.(1-4) Besides intrinsic interest in the x-ray scattering cross-section and its description, studies of this type are motivated by the possibility that new structural and magnetic properties of rare earth metals might be revealed, and that new techniques may thereby be developed. As a result, interest in x-ray magnetic scattering experiments. has grown rapidly during the last 10 years particularly, with the regular application of synchrotron radiation techniques- Magnetic scattering experiments have by now been performed at most of the x-ray synchrotrons around the world. In addition, insertion .device beamlines dedicated to x-ray magnetic scattering experiments are planned at each of the next-generation storage rings presently under construction in the United States (APS), Europe (ESRF), and Japan (SPRING-8). Generally, the results of x-ray magnetic scattering experiments may be analyzed within two regimes of the incident x-ray energy, namely, in the limit of high x-ray energies, when the incident x-ray energy lies above the excitation energy of any absorption edge, and at resonance, when the incident energy lies near an absorption edge. In the high energy limit, the amplitude for x-ray magnetic scattering has the simple form [L(Q)?A + S(Q)?B](5-7) Here, L(Q) and S(Q) refer to the Fourier 'transforms of the atomic orbital and spin magnetization densities, respectively, and the vectors A and B depend on the incident and scattered wavevectors and on the: incident and scattered polarization vectors. 7) Because the vectors A and B are not identical, the polarization dependence of the orbital contribution to the magnetic cross-section differs from that of the spin contribution. This leads to the possibility that the orbital and spin magnetization densities maybe distinguished, in x-ray scattering experiments. The same distinction is not directly possible by neutron diffraction techniques (in dipole approximation, where the polarization dependence of the orbital contribution is identical to that of the spin contribution), and is important to a fundamental understanding of the electronic structure of magnetic materials. A particular

Jan 1, 1992

By T. J. White

Each year, thousands of tons of toxic concentrates are produced as the unwanted byproducts of industrial operations and smelting activities. The fate of these materials remains open, as in general their consumption is limited and potential markets contracting. Xtaltite (pronounced crystal-tight) is a Synthetic Mineral Immobilization Technology (SMITE) optimized for the concentration, detoxification and consolidation of toxic metal wastes. In this approach, we seek to mimic nature to produce durable synthetic minerals that survive for aeons in well characterized geological settings. This approach has high public acceptability because the concept is easily understood by the layperson and the long term stability of the waste form may be predicted with confidence. In addition, where Xtaltite is used for mine backfill, a system of ecologically sustainable mining development is established. This paper details the design and fabrication of Xtaltite under oxidizing and reducing conditions. To illustrate and contrast these stabilization regimes, specific reference will be made to the treatment of thallium, chrom~um and arsenic wastes. Waste form performance under TCLP, dynamic boiling water tests and in other leaching media will be compared and discussed with respect to their relevance to different disposal options.

Jan 1, 1995

By T. J. White

Xtaltite is the trade name for a generic technology which exploits the well known insolubility of some minerals, which naturally incorporate toxic waste elements, to consolidate and immobilise a range of inorganic waste products. It is a specific case of synthetic mineral immobilisation technology (SMITE) which is already used to immobilise high level nuclear wastes (HLW. Although HLW is highly toxic, it exists in relatively small volumes, occurs in central facilities and may be stabilised at low waste loading (< 10 wt%). In contrast, heavy metal wastes are of considerable volume, therefore Xtalitite waste forms must routinely accommodate high waste loadings (usually in excess of 30 wt% for a particular toxic oxide or combination of oxides) and be suitable for fabrication in remote locations using relatively simple technology. This paper details the methodology underlying Xtaltite, with particular emphasis given to the interplay between solid state chemistry, durability and economic considerations. Specific reference is made to the treatment of arsenious and mercurial wastes.

Jan 1, 1994

By John G. Reid

When the paper "Operations at the Greenvale Nickel Project Mine and Refinery" was delivered at the 1st International Laterite Symposium in February 1979, the Yabulu Caron plant had been operating for four years and production had just stabilized. The design had been based closely on the Caron plant at Nicaro, Cuba, built in 1944, also by Freeport. Yabulu had 10 Herreshoff ore roasters and production in 1978 was 18,682 tonne nickel as impure oxide sinter and 763 tonne cobalt in a mixed sulphide with a cobalt to nickel ratio of 1 :2.5. In the 25 years since the 1st Symposium, two more roasters have been added, but dry ore processing rate has remained relatively unchanged at 2.4M Uyr to allow a lower feed rate per roaster with associated higher recovery. The ore source has changed from the domestic Greenvale mine to imports from New Caledonia, Indonesia and the Philippines. Nickel production between 1978 and 2003 has risen by 67%, cobalt has risen by 146% and the products have changed to high purity nickel compacts and "ChemGrade" cobalt salt. The plant changes that have contributed to the increased recovery, production and product value are discussed. Keywords: Caron, Yabulu, nickel, cobalt, ammonia

Jan 1, 2004

By Timothy W. Skszek, Adrian S. Sabau, Hebi Yin, Gerard M. Ludtka, Xiaoping Niu

"A constitutive model has been developed to predict the yield strength aging curves for aluminum casting alloys during non-isothermal age-hardening processes. The model provides the specific relationship between the process variables and yield strength. Several aging heat treatment scenarios have been investigated using the proposed model, including two-step aging recipes. Two-step aging heat treatments involve a low temperature regime to promote nucleation of secondary phases and a second step at higher temperature for the growth of the secondary phases. The predicted results show that a yield strength of approximately 300MPa might be obtained in a shorter aging time, of approximately 30 minutes. As a result, better mechanical properties can be obtained by optimizing the time-temperature schedules for the precipitation hardening process of heat treatable aluminum alloys.IntroductionA356 is one of the commercially heat treatable aluminum casting alloys, and T6 is one of the heat-treated conditions to improve mechanical properties. The first stage of a T6 temper is solution treatment at an elevated temperature, generally in the range of 480 - 540°C. After solution treatment, the cast part is typically quenched in water/air to retain the solute-rich homogeneous matrix chemistry at room temperature. Subsequent ageing treatment stages capitalize on this super-saturated solid solution to generate controlled dispersions of very small strengthening precipitates within the matrix of Al grains [l]."

Jan 1, 2013

By Yun Li

In 1999 Yunnan Copper Corporation (YCC) decided to modernise their copper smelter and change the existing sinter plant I electric furnace process to a combination of ISASMEL T and electric slag cleaning furnace. The main aim of the project was to improve the environmental performance and decrease the energy consumption. Generally the project has been successful, partly attributable to the selection of a reliable and fully demonstrated technology. The design capacity for the ISASMELT furnace is 600,000 tonnes of dry copper concentrate per year. The furnace has been running smoothly since heat up in May 2002. YCC expended considerable effort in the preparation for plant operation. An extensive training program for key YCC personnel at the Mount Isa Copper Smelter improved their understanding of the process significantly and ensured successful hand-over of the technology. This paper describes the project history and summarizes initial operating results.

Jan 1, 2003

By Yun Li

In 1999 Yunnan Copper Corporation (YCC) decided to modernise their copper smelter and change the existing sinter plant I electric furnace process to a combination of ISASMEL T and electric slag cleaning furnace. The main aim of the project was to improve the environmental performance and decrease the energy consumption. Generally the project has been successful, partly attributable to the selection of a reliable and fully demonstrated technology. The design capacity for the ISASMEL T furnace is 600,000 tonnes of dry copper concentrate per year. The furnace has been running smoothly since heat up in May 2002. YCC expended considerable effort in the preparation for plant operation. An extensive training program for key YCC personnel at the Mount Isa Copper Smelter improved their understanding of the process significantly and ensured successful hand-over of the technology. This paper describes the project history and summarizes initial operating results.

Jan 1, 2003

By Yi Feng Shi

The ISASMELT process is a submerged lance smelting technology operating in smelters in Australia, the USA, Belgium, India, Germany, Malaysia and China. Further plants are under construction in Peru and Zambia. Initially developed at Mount Isa Mines, Australia, the technology is marketed by Xstrata Technology to companies around the world. Yunnan Copper Co. Ltd. (YCC) commissioned the first copper ISASMELT furnace in China in 2002. The plant quickly ramped up to design capacity and the first campaign lasted more than 2 years. Now into the second campaign, the furnace is exceeding the original design capacity and YCC has won numerous awards for its contribution to reducing emissions and energy consumption. YCC and Xstrata put great effort into managing the design, construction and commissioning of the smelter. Xstrata?s technology was combined with YCC?s novel management approach. This effort has been repaid in terms of the outstanding performance of the plant since startup. This paper updates the reader on the first few years? operation of the YCC ISASMELT plant and discusses the way in which the technology was transferred, leading to fast rampup and, as a result, enhanced profitability for the operators.

Jan 1, 2006

By J. Bostjancic

As wastewater discharge regulations become more stringent, power plants, manufacturing plants and other industrial sites are looking for ways to reduce makeup water requirements and to recycle and reuse as much wastewater as possible. In some cases, environmental regulations require zero liquid discharge, meaning all wastewater must either be retained on site or reduced to solids for disposal off site. Zero liquid discharge or "closed-loop" wastewater treatment systems using evaporators and other process equipment have been well-accepted in recent years. Often overlooked is the fact that zero discharge is not just the latest fashion--many commercial zero liquid discharge systems have been in operation since the mid-70&apos;s. This paper will give specific examples of zero liquid discharge operations from 1974 to the present, showing how evaporation equipment and processes have changed to meet the requirements of industry and environmental regulations.

Jan 1, 1996

By H. Kamarudin

The behaviour of cassiterite-sulphosuccinamate flotation system was examined in the light of zeta potentials measured by micro-electrophoresis method. It was observed that sulphosuccinamate substantially affects the zeta potentials of cassiterite, lowering its i.e.p. to pH 2.5 and indicating a specific adsorption and/or chemical interaction. The optimum concentration for flotation, as seen in micro-flotation tests, was found to be associated with the most effective lowering of the zeta potentials, the optimum pH being 3.0. The effect of cations in the pulp was examined for the presence of ferrous, ferric, aluminium and lead ions. The ions ferric and aluminium were observed to create an intense effect of increasing the potentials to positive side, possibly due to adsorption of cation hydroxy complexes, as indicated by their respective species distribution diagrams.

Jan 1, 1994

By S. Ferlay

"The main purpose of the ZIMA VAL project (Label EUREKA EU1367 and LIFE ENV/F/000278) is to demonstrate industrial scale recovery and recycling of the main components of used dry batteries (zinc, manganese dioxide, mercury, and stainless steel) into high added value products. The originality of the ZIMA VAL process resides in:1- the use of hydrometallurgy2- alkaline treatment implementation (highly selective) for zinc and mercury3- electrochemical recovery of high quality products.4- the recycling of all the battery components (zinc, mercury, manganese dioxide, stainless steel) ·5- low operating and investment costs.The process consists of physical classification, mechanical dismantling, hydrometallurgy and electrochemistry. The purpose of the demonstration plant in FALAISE (Calvados - France) is to define the technical and technological parameters of an industrial unit for the treatment of 2400 tonnes per year of used batteries."

Jan 1, 2000