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See how the world voted! View the top 100 moments in history.
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President Obama recently announced plans to scrap NASA’s Constellation moon-landing project and to redirect funding toward programs that will lay the groundwork for a 2030 Mars expedition. This month JOM asks, what is the impact of the new priorities for NASA?
• The United States will lose its status as a worldwide leader of human spaceflight
• Scientific advancement will be stalled as R&D funding is redirected
• Commercial space launch services will be stimulated to fill the void left by NASA’s new priorities
• The U.S. space program will ultimately be better positioned for deep space exploration
The poll is conducted via the JOM Reader Zone of the TMS Discussion Board. |
| SAMPLE JOM |
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JOM MAY 2001
VOLUME 53, NO.5
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![May 2001 Cover: Classically, recycling has provided the optimal way to circumvent the energy-intensive Hall-Heroult process. As described in this month's issue, inert anodes may change our perspective on reduction.The cover shows aluminum beverage cans being recycled at an Alcan plant in Oswego, New York. (Photo courtesy of Alcan.) This edition also presents coverage of combustion processes in pyrometallurgy. [Click to enlarge]](http://www.tms.org/pubs/journals/jom/0105/cover-0105.gif)
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Inert Anodes: An Aluminum Revolution?
Combustion Processes in Pyrometallurgy
Battlebots: Metal-on-Metal Television |
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Built to Battle, Robots Test Designers' Mettle
By: Maureen Byko
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Advisors: Chris Bickert, Aluminum Pechiney; Rob Stephens, Cominco Research |
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Published monthly by The Minerals, Metals & Materials Society for its members, JOM is a technical journal devoted to exploring the many aspects of materials science and engineering.
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COMBUSTION IN PYROMETALLURGY
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Combustion Processes in Pyrometallurgy
[p. 15
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Author(s): Robert L. Stephens
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Combustion processes, which affect both the heat balance and the chemical reaction within the furnace, are fundamental to pyrometallurgy. This article introduces the topic of combustion in pyrometallurgy with an overview of the three articles that follow. The articles address the kinetics of flash-and bath-smelting processes, and also elaborate on the technique of oxy-fuel combustion that ensures low NOx emissions.
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Combustion in Flash Smelting Furnaces
[p. 16
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Author(s): F.R.A. Jorgensen and P.T.L. Koh
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The reaction shaft is the heart of a flash smelter. Current knowledge of the combustion of concentrate and ancillary fuels (coal, oil, and gas) in flash smelter shafts comes from laboratory studies, plant measurements, and physical and mathematical modeling. The latter is particularly useful when considering the complications of two-phase flow of particles and gas and chemical reactions; however, uncertainty as to effective particle size requires validation to establish confidence in the model outcomes. Those issues are addressed in the paper, together with the importance of the burner in achieving good mixing and dispersion. Simulations, which may be viewed on the web, show the consequences of poor mixing.
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Praxair's Dilute Oxygen Combustion Technology for Pyrometallurgical Applications
[p. 21
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Author(s): M.F. Riley, H. Kobayashi, and A.C. Deneys
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Dilute oxygen combustion (DOC) technology uses separate high-velocity fuel and oxygen jets to generate strong in-furnace gas recirculation, producing combustion between the fuel and a highly diluted oxygen and furnace-gas mixture. These very low NOx oxy-fuel burners have been developed and commercially demonstrated in steel reheating furnaces. The burner design meets industry needs for increased productivity and lower operating costs with minimal capital expense and low maintenance. The performance of DOC technology has been measured under laboratory and industrial conditions encompassing both natural gas and coke oven gas firing, and a wide range of furnace temperatures and nitrogen levels that simulate air infiltration. This paper describes the results of the tests using natural gas as the fuel and lists potential applications for DOC technology in the non-ferrous metals industry.
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Kinetics of the Reactions in the Smelting Furnace of the Mitsubishi Process
[p. 25
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Author(s): Zenjiro Asaki, Toru Taniguchi, and Mineo Hayashi
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In this paper, the authors present the results of theoretical calculations on the rates at which copper concentrate particles and silica particles dissolve in the matte in the smelting furnace of Mitsubishi process. Those calculations indicate that the concentrate particles dissolve rapidly in matte, in less than 1 ms, whereas silica particles dissolve at a much slower rate, and they dissolve mainly in the bulk matte in the smelting furnace. Some advantages of bath smelting over flash smelting are given.
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Inert Anodes and Other Technology Changes in the Aluminum Industry--The Benefits, Challenges, and Impact on Present Technology
[p. 28
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Author(s): Les Edwards and Halvor Kvande
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A revolution may be coming to the aluminum industry in the form of inert anode technology. This article outlines the reason for the high interest stirred by inert anodes, and describes five articles in this issue of JOM dedicated to the topic. The papers were presented at the 2001 TMS Annual Meeting in February, and were followed by a panel discussion.
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Inert Anodes for Al Smelters: Energy Balances and Environmental Impact
[p. 29
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Author(s): Halvor Kvande and Warren Haupin
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This paper assesses the energy and environmental consequences of retrofitting aluminum electrolysis cells with inert anodes. The energy consumption and the CO2 emissions are calculated based on assumptions of what the cell voltage may be. It is crucial not to ignore the cell voltage increase that may be necessary to maintain the heat balance of the cell, and also the sources of electrical energy that would provide the incremental power. Thus, a global environmental analysis of the impact of retrofitting cells with inert anodes is needed.
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Inert Anodes for the Hall-Heroult Cell: The Ultimate Materials Challenge
[p. 34
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Author(s): Donald Sadoway
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Inert anodes have been considered for years to be the future of aluminum production. Research is continuing on materials that would best serve that purpose. Results of studies on three possible materials are presented in this paper: ceramics, cermets, and metals. At this time, metals appear to be the most suitable material for inert anodes.
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Cell Operation and Metal Purity Challenges for the Use of Inert Anodes
[p. 36
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Author(s): Jomar Thonstad and Espen Olsen
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Inert anodes demand a fairly high alumina content (> 50% saturation) in the electrolyte, requiring a new way to control the alumina concentration. Probably the greatest challenge is how to tackle anode corrosion, which gives rise to metal contamination. All candidate oxide materials that can be used as components of inert anodes have a finite solubility in the electrolyte. Consequently, the anode materials will corrode slowly, and the corrosion products will be reduced into the aluminum produced. Even if the anode corrosion rate is slow (10-20 mm/year), an unacceptable contamination of the aluminum may result. Possible ways to reduce the contamination are discussed.
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Next Generation Vertical Electrode Cells
[p. 39
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Author(s): Craig Brown
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The concept of the vertical electrode cell (VEC) for aluminum electrowinning is presented with reference to current research. Low-temperature electrolysis allows non-consumable metal-alloy anodes to show ongoing promise in laboratory tests. The economic and environmental advantages of the VEC are surveyed. The unique challenges of bringing VEC technology into practice are discussed. The current status of laboratory research is summarized. New results presented show that commercial purity aluminum can be produced with promisingly high current efficiency.
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The Economics of Inert Anodes and Wettable Cathodes for Aluminum Reduction Cells
[p. 43
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Author(s): Jeff Keniry
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Estimating the impact of inert-anode and wettable-cathode technologies on smelter costs must be speculative because no such technologies have yet been commercialized. Even so, some broad conclusions can be drawn about the economic merit of inert anodes in retrofit and greenfield smelter scenarios. Study suggests that retrofitting inert anodes to existing prebake cells generates insufficient economic benefit to justify this objective. Drained cathode cells offer potential for energy savings coupled with increased production, provided that the cell life is greater than three years. Unlocking the potential value of both inert anode and wettable cathode materials will require their use in vertical electrode configurations, where the impact on operating costs and, particularly, capital costs, is expected to be significant. To be economically and technically viable, vertical electrode cells will require wear rates of less than approximately 5 mm per year on the inert electrode surfaces, much less than has so far been reported.
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Inert Anodes and Other New Al Technologies--The Benefits, Challenges and Impact on Present Technology
[p. 48
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Author(s): Les Edwards, Nolan Richards, and Halvor Kvande
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A panel discussion on inert anode technology concluded a popular symposium on the topic during the 2001 TMS Annual Meeting in February. The discussion, which included contributions from six experts in the technology, was a question-and-answer session for audience members. A summary of that discussion is presented here.
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Built to Battle, Robots Test Designers' Mettle
[p. 12
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Author(s): Maureen Byko
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Within the last year, two television networks have launched programs geared toward technically advanced audience members: BattleBots on Comedy Central and Robotica on The Learning Channel. The programs involve competitions between remote-controlled robots, that, in episodes most pleasing to audiences, send metal flying as materials and workmanship are put to the test on an arena floor. This article considers the programsÆ appeal to robot enthusiasts, and their potential for creating a new generation of math and science enthusiasts.
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In the Final Analysis
[p. 1
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Author(s): James J. Robinson
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U.S. President George W. Bush has ideas for government spending that do not necessarily coincide with the ideas of the science community. In this monthÆs editorial, James Robinson considers BushÆs budget proposal that would cut spending for advanced technology research, along with programs to improve energy efficiency and to mitigate global climate change.
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Foundation News
[p. 10
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Author(s): Anonymous
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The winners of the Fourth Annual Foundation Golf classic are announced in TMS Foundation News. The golf outing was the opening event for the 2001 TMS Annual Meeting & Exhibition
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News and Update
[p. 4, 6
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Author(s): Anonymous
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This department features recent developments in extraction and processing; light metals processing; materials processing and manufacturing technology; structural materials; electronic, magnetic, and photonic materials; government and policy; and TMS news.
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Meetings Calendar
[p. 51
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Author(s): Anonymous
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A monthly round-up of soon-to-be-held meetings and upcoming calls for papers.
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Consultants Directory/Classifieds
[p. 54
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Author(s): Various Contributors
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Positions and services available. (You may view "Consultants Directory" or "Classifieds" in HTML format or click on the button to download both departments as they appear in the print version of the journal.)
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![May 2001 Cover: Classically, recycling has provided the optimal way to circumvent the energy-intensive Hall-Heroult process. As described in this month's issue, inert anodes may change our perspective on reduction.The cover shows aluminum beverage cans being recycled at an Alcan plant in Oswego, New York. (Photo courtesy of Alcan.) This edition also presents coverage of combustion processes in pyrometallurgy. [Click to enlarge]](http://www.tms.org/pubs/journals/JOM/0105/cover-0105.large.gif)