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By Tian Sugui

By means of the measurement of the enduring property and microstructure observation, an investigation has been made into the influences of the element Re and TCP phase on the enduring property of the single crystal nickel base superalloys. Results show that the needle-like TCP phase is precipitated along the <110> orientation on {111} planes in Re-containing/free superalloys during the long term aging, the TCP phase is identified as µ phase, and the precipitated µ phase in 4.5%Re alloy is gradually spheroidized during aging. Thereinto, the needle-like µ phase may obviously decrease the enduring lifetimes of the alloys due to the consumption of the refractory elements and the effect of the stress concentration. But the stress concentration is not easily generated in the regions near the spherical-like µ phase, which is a main reason of reducing the enduring lifetime of 4.5%Re alloy to a small extent.

Jan 1, 2010

By M. Faraji

Inclusions formed in a high-carbon, manganese-silicon killed plain steel (Fe-0.77C wt%) were studied. Various techniques were used to characterise the inclusions, and the latter were classified according to their chemical composition, size and morphology. The main constituent elements entering the inclusions were Mn, S, Al, and oxygen. Alongside MnS and some Al2O3 inclusions many non-metallic inclusions appeared in complex forms, consisting of silicates, sulphides and oxides. Duplex oxy-sulphides, mainly MnS combined with Al2O3, or SiO2 were the most common complex multiphase inclusions in this steel. The nanoindentation technique was used to assess and rate different types of inclusions and data of the hardness and elastic modulus of individual inclusions at room temperature are presented.

Jan 1, 2010

By R. Fragoudakis

AISI 4130 steel is a medium carbon Cr-Mo steel used in automotive, aeronautic and other general-purpose industries. In this study, 4130 steel fatigue specimens were carburized at 927oC to enhance the carbon content in the steel, raising it from approximately 0.30% (non-carburized) to 0.90% (carburized, oil quenched and tempered). Rotating bending fatigue tests were performed on the R. R. Moore Rotating Beam Fatigue Testing System, in order to determine the high cycle fatigue (HCF) life of 4130 steel and plot the corresponding S-N diagrams. A comparison of the results of carburized and non-carburized specimens shows that carburizing of steel: a) increases the surface hardness and b) improves the fatigue strength of the steel by at least two orders of magnitude.

Jan 1, 2010

By Seong- Rin Lim

Light-emitting diodes (LEDs) are regarded as environmentally friendly light sources due to their high energy efficiency and lack of mercury content. LEDs are used for a variety of domestic and commercial lighting systems, where they are replacing incandescent and fluorescent lamps at a rapid rate. Incandescent lamps inefficiently consume energy because electricity is mostly converted to heat rather than light. This causes unnecessary environmental impacts and energy consumption associated with power generation and transmission from a life cycle perspective. Although fluorescent lamps are more energy-efficient than incandescent lamps, their disposal at end-of-life presents special challenges because of the presence of toxic mercury. Despite the seemingly apparent advantages of LED, very few studies have rigorously addressed potential environmental consequences of their disposal. Specifically, LEDs are designed with III-V semiconductors that presumably consist of toxic and rare materials, including arsenic, gallium, and indium. We hypothesize that, depending on their concentrations and leachability, these constituents may also contribute to render LEDs as hazardous waste at the end of their useful life.

Jan 1, 2010

This paper outlines the complete failure of the U.S. in status and relevance in Rare Earth Oxides (REO). Although rare earth oxides are strategic and critical in their own right, refining these REOs into elements and alloys is even more important for the development of "Green Technologies" and advanced weapons systems. America does not have an active domestic source of rare earth oxides. America does not have any heavy rare earth elemental or alloy capabilities. The magnitude of this failure continues to become more apparent as the manufacture of REO based electronics and magnetic components moves eastward towards China. China has succeeded in outmaneuvering the United States and the world in its quest to control the rare earth oxides, elements and alloys, and the many industries dependent upon REO. What can be done?

Jan 1, 2010

By Geysen. Daneel

Better slag valorization is part of improving the sustainability of steel, stainless steel and non- ferrous metal production processes. Besides, it can improve the sustainability of other products and production processes as well. A sound and well established slag valorization is beneficial for the overall economics, marketing and appreciation of the metallurgical process and its products. On 6-7 April 2009, the First International Slag Valorisation Symposium was held in Leuven, Belgium. This paper gives a brief summary of the symposium, providing an overview of slag valorization opportunities. The authors believe that high temperature process slags can have interesting applications and that within the next 10 to 20 years slags will need such valorization options in order to compete with other materials and get general support for further production. On the other hand, the authors also expect a higher demand for slags for the production of various materials. High temperature processes should anticipate on the growing opportunities for valorization of slags and increase the resilience of their process by better understanding slag processing, slag quality and material requirements. More interdisciplinary research efforts are required to reach this level of knowledge for the different high temperature processes. Such an interdisciplinary research platform was recently established at KULeuven, Belgium, named SMART-PRO2 (Sustainable Materialization of Residues from Thermal Processes into Products).

Jan 1, 2010

By B. Sereda

As it is known the creation and development of new titanic alloys has been problematic up to now. They can be used in aircraft and vehicle construction, shipbuilding and as materials for keeping static loadings in high-temperature environments. In this work the synthesis of various titan aluminides is investigated. Mathematical model of structurization process was done. On the base of retrieved model the mechanisms of structurization in systems Ti + Al and Ti + 3Al was determined. Experimental researches were done at two different modes: burning and thermal spontaneous ignition. The method of retrieving compacted products combusted in SHS conditions (SHS-compacting) was used to gain these intermetallic compounds. The physical and thermal characteristics of technological process and their influence on structurization, homogeneity of structure and porosity of titan aluminides have been simulated and researched. It is established that the SHS-compactizing technology is fully capable of supervising the process of structurizations with the whole complex of advantages and can be applied for receiving qualitative titan aluminides with the set of chemical-physical properties.

Jan 1, 2010

By Arsenio Enriquez, Adrian Deneys

"Rio Tinto through its subsidiary Kennecott Utah Copper Corporation (KUC) and Praxair have implemented the CoJet® gas injection system for copper anode refining. The system provides the capability to melt on average 60 to 70 tons of scrap copper per heat (with acceptable NOx emissions). The system has demonstrated the potential for tuyere-less sulfur and oxygen removal using coherent jet technology.This paper describes the process concept, system development, laboratory testing, implementation, current operation and ongoing developments."

Jan 1, 2009

By Markus A. Reuter, Jacob Wood, Robert Matusewicz

Over the last 20 years, significant improvements in copper smelter productivity have been realized through the advent of continuous smelting processes. This progress has until recently however, not been carried through to copper converting. Peirce-Smith converting has been widely used by the copper industry for 100 years but is limited by its batch nature in achieving large scale of production. A logical next step is therefore copper converting on a continuous basis with its inherent environmental benefits. A number of continuous converting technologies are currently in use or being developed within the copper industry, the majority of these operating with calcium-ferrite slags. A notable exception however is the Ausmelt Continuous Copper Converting (C3) technology which has focused on operation with ferrous-calciumsilicate or loosely called olivine type slags. This paper discusses the merits of the Ausmelt C3 process and the advantages offered in terms of operational flexibility and process control arising from the use of lime modified iron silicate slags. It also examines the effects of key process variables pertinent to continuous copper converting from both a theoretical and experimental/operational perspective.

Jan 1, 2009

By Luis M. González, Guzmánm Guillermo D., Davis Juan C.

"The Teniente converter (CT) of the Ventanas Smelter and Refinery of Codelco-Chile has two tuyeres for dry concentrate injection directly into the melt.The diluted phase injection system can feed 15 to 20 kg of concentrate for 1 kg of air, which creates a very abrasive solid/gas phase. The tuyeres commonly used lasted for about 3.5 days due to the accelerated decay of the shell, and 1.5 hours were necessary for the replacement of new ones in the reactor.Tests were carried out with common shell tuyeres with a tungsten based welding cover, and a life span of 28 days was reached, increasing the Teniente converter operational continuity between 1.5 to 2 %."

Jan 1, 2009

By Viviane Tavares

The technology advance of mobile devices makes consumers of these equipment do more constant exchanges, with this the obsolete devices discarding becomes an environmental problem, due its landfill accumulation. In order to minimize the environmental impacts caused by these equipment there?s the recycling necessity of polymers, ceramic and metallic materials. The main goal of this recycling is to study the printed circuit board of device mobile processing through ore treatment in order to recoup copper. Initially printed circuit boards were processed in a knives mill, in order to liberate the ferrous material, after that it was done the magnetic separation of the reduced residue. With the not magnetic fraction it was done the grain sized analysis and sulfuric acid and hydrogen peroxide leaching analysis. With the chemical analysis results proceeding from the leaching aliquot it was possible to observe that the leaching method with sulfuric acid and hydrogen peroxide presented greater copper recovery.

Jan 1, 2009

By Kotaro Ogura

"Ethylene has been produced in aqueous solution from CO2 by the electrochemical reduction driven by a natural energy. This process is useful for storing a large amount of the natural energy. In the closed system, the conversion efficiency of CO2 is almost 100%, and the maximum selectivity for the formation of ethylene is more than 70%. On the other hand, the current efficiency for the competitive reduction of water is less than 10%. The electrolysis is practicable under such special conditions as three-phase interface consisting of gas, solution and metal, concentrated solution of potassium halide, low pH and copper or copper halide-confined metal electrode. These requirements are thoroughly examined, and the grounds to reply upon are revealed. A series of chemical apparatuses including an electrolytic cell in a large scale are designed for the ethylene production, which allow us continuously to supply raw CO2 and to extract the product.IntroductionIn connection with the depletion of the petroleum reserve, much attention has been paid to the utilization of natural energies such as sunlight, wind force and waves. However, these energies are always changeable, and some means of storing them are necessary for the common use. In general, natural energies are transformed to the electric energy at the time of utilization, but the electricity is not very storable. This is one of the reasons why the application of natural energy is not so expanded. On the other hand, the storing of natural energy by plants is very skilful. In the photosynthesis, solar energy is transformed to chemical energy by fixing carbon dioxide."

Jan 1, 2009

By Zhigang Liang

A carbon free precast block was prepared by using high-alumina fused corundum as aggregate and fused magnesia, and ultra-fine Al2O3 and ultra-fine SiO2 powders as matrix materials. A small linear expansion for the precast block was achieved through spinel formation from the reaction of MgO with Al2O3. The precast block showed a lower apparent porosity, higher hot modulus of rupture and better slag corrosion resistance compared to the traditional Al2O3-MgO-C brick. Moreover, the practical application of the precast block to the ladle lining proved it to possess a better thermal insulation which could effectively prevent the temperature drop of molten steel during the refining process. It can be predicted that the carbon free precast block could possibly be accepted as a new type of ladle lining material for the production of low-carbon and ultra-low-carbon steel.

Jan 1, 2009

By Nikhil Dhawan

Electronic waste (e-waste) is a collective name given to discarded electronic devices such as Television, Cellular Phones and Personal Computers. Among the heterogeneous metals present in the e-waste are the base metals: copper, aluminium, nickel, tin, zinc, iron and precious metals: gold, silver, palladium, platinum apart from several hazardous and halogens metals. Hence there is a need to recover these metals from electronic scrap by recycling and then re-use, which can meet large amount of metals demand. Hydrometallurgical processing was employed for the recovery of metals from television printed circuit board (TV PCB). Different lixiviants such as hydrochloric acid, Sulphuric acid, and nitric acid were used to understand the dissolution behavior of copper, iron and lead present in the TV PCB. Effect of increasing concentration of nitric acid was also studied. Selective recovery of tin over 95% in the form of tin oxide was precipitated. The precipitated tin oxide was identified by X-ray diffraction technique. Tin oxide of purity more than 99.9% was obtained.

Jan 1, 2009

A sinter plant baghouse dust has been treated as a hazardous solid waste, and disposed at a very high price. A series of leaching tests were conducted to examine the possibility to produce high grade potassium chloride from the solid waste. It is found that around 40% of the solid wastes can dissolve into water, and a deposit with more than 90% KCl can be produced after simply drying the solution.

Jan 1, 2009

By Jared Ball, Benjamin Hogg

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

Jan 1, 2009

By M. E. Coleman, G. Money

"Clyde Materials Handling is an established customer-driven solutions provider, which utilizes its knowledge, expertise and technologies to transform the production processes of its customers, who operate in the ferrous and non-ferrous metals industries.With over 30 years experience in the process improvement industry, Clyde Materials Handling has helped their global customer base transform the way in which they operate their processes, which has enabled them to generate sustainable economic benefit and maintain their positions as leaders in their respective markets.Clyde Materials Handling has supported operators within the metals market by developing and deploying pneumatic conveying and pneumatic injection technologies. These environmentally supportive and sustainable solutions have been used to transport raw materials within operating facilities, from storage to silo, as well as injecting these materials directly into the heart of production processes.Clyde Materials Handling has worked closely with their customers, such as Codelco in Chile, where their pneumatic solutions have been used to inject a consistent, pulseless and accurate flow of copper concentrate into a bath smelter, which has helped to fuel the operational capacity, availability and productivity.This paper will discuss and highlight the ways in which pneumatic injection technologies, created by Clyde Materials Handling, and applied in partnership with their customers, have helped to improve the operational performance of the production processes of operators across the non-ferrous metals markets with specific reference to applications in the Peirce Smith Converter.Clyde Materials Handling has applications injecting Electronic Scraps, Dusts, Reverts, and other additives to the Peirce Smith Converter. They also have experience of modified PS Units used for Slag Cleaning. There experience with the Codelco Teniente Converter is also directly related to this area of operation."

Jan 1, 2009

By Kosei Morita, Osamu Nakano, Katsuhiko Nagai, Kazuhiro Mori

"The Sumitomo Toyo Smelter and Refinery commenced its operation in 1971 with three Peirce- Smith (PS) converters. “2 hot – 1 blowing” operation was practiced, that is one of two available converters was blowing and the other was standby in a hot state while the third converter was under repair. After several improvements, the stack time ratio reached around 90%; and processing 5 batches a day became possible.As a result of the expansion program of the Toyo smelter and refinery that started in 2001, the converter operation pattern was shifted from “2 hot – 1 blowing” to “2 hot – 2 blowing” with the installation of second converter blowers and an additional ladle crane.In 2005 a, the fourth converter was installed and “3 hot – 2 blowing” operation began. Also, with improvements experienced in the anode furnaces and the anode-casting wheel operation, today, the number of cycles has been increased up to more than 8.5 a day.The treatment techniques of fugitive gas containing sulfur dioxide from converter furnaces have been gradually reinforced, and the fixation rate of treated sulfur is currently being maintained at more than 99.9%. This paper introduces the operations described above, and the improvements in environmental management techniques for the Toyo PS converter operation."

Jan 1, 2009

By Zhao-cheng Liu

Iron oxide red pigment powders of high quality were synthesized from pyrite cinders. Iron ox-ide red pigment powders were synthesized by hydrothermal method from the precursor of Fe(OH)3 and Fe(OH)2 colloid, which were obtained after ammonia solution reacted with acidic leaching solution produced by the reaction of pyrite cinders with sulfuric acid. Effects of reaction concentration, reaction temperature, reaction time, pH value and n(Fe2+)/n(Fe3+) on main properties of oxide iron red were studied by experiments. The prepared particles were characterized by means of X-ray diffraction (XRD) and scanning electron microscope(SEM). The results revealed that the synthesized iron oxide red particles were _-Fe2O3 and pseudocubic with particle size of 0.50~0.75µm. Furthermore, the quality of iron oxide red pigment powders reached the first grade of national standard (GB1863-89 ).

Jan 1, 2009

By Joël P. T. Kapusta, Romeo U. Pagador, Noparut Wachgama, Chumnoom Khuankla

"Thai Copper Industries (TCI) is a custom copper smelter and refinery in Rayong, Thailand, with an annual capacity of 165,000 tons of cathodes. It employs the El Teniente Technology as the primary smelting reactor to produce white metal from copper concentrates. The white metal is further treated in Hoboken Siphon Converters to produce blister copper then refined in anode furnaces before being cast into anodes for electro-refining in the on-site tankhouse.Thai Copper Industries is the first copper smelter to install and successfully operate on a commercial scale with the Air Liquide Shrouded Injection (ALSI™) Technology in the Hokoben converters with sonic injection of oxygen enriched air and nitrogen for cooling of the injector tip areas. Following commissioning and the establishment of operating practices, the performance of the Hoboken converters with ALSI™ Technology produced outstanding results. The unique combination of an El Teniente and Hoboken siphon converters, both of which are bath smelting operations, offers very high blowing and oxygen efficiencies. As a consequence, reverts recycling was accelerated with minimal build up on the mouth, end-plates or even below the siphon that is typical in Hoboken converters.These outstanding results in the Hoboken Siphon Converters with ALSI™ Technology helped the TCI Plant reach a production of about 75% of its capacity within four months despite the fact that the TCI staff is quite young and its converter know-how and experience are not yet fully developed."

Jan 1, 2009