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November 2012 JOM Focuses on Primary Metals Production|
Posted on: 10/16/2012 12:00:00 AM... Primary metals production—from ancient metal to cutting-edge processing innovations—is the theme of the November 2012 JOM.TECHNOLOGY DEVELOPMENTS IN NONFERROUS PYROMETALLURGY
Optimization of Fluidized Roasting Reduction of Low-Grade Pyrolusite UsingBiogas Residual as Reductant
A synopsis of the 12 papers and one commentary comprising the four technical topics supporting this month’s theme is provided below. For updates on TMS activities, read the journal’s News and Update section and TMS Executive Director Jim Robinson’s Final Analysis on the potential impact on scientific advancement posed by looming restrictions on U.S. government travel.
To read this JOM issue online, go to Springerlink.
HYDROMETALLURGY FUNDAMENTALS AND APPLICATIONS
Innovations in Hydrometallurgical and Electrometallurgical Processing: A TMS2012 Symposium Sampling
Michael L. Free and Shijie Wang
This commentary offers a summary of papers presented at two symposia at the TMS 2012 Annual Meeting and Exhibition and included in this issue of JOM. The T.T. Chen Honorary Symposium on Hydrometallurgy, Electrometallurg,y, and Materials Characterization was organized to celebrate Chen’s outstanding contributions to the science and practice of extractive metallurgy and to honor his pioneering studies on the characterization of metallurgical products. The Electrometallurgy 2012 symposium was focused on fundamental research, development, and/or application of innovative aqueous or molten salt electrometallurgical processing technologies for the extraction, concentration, recovery, refining, environmental treatment, and recycling of metals from ores, concentrates, process solutions, scrap or waste.
Metal Separation and Recovery in the Mining Industry
Steven R. Izatt, Ronald L. Bruening, and Neil E. Izatt
Molecular Recognition Technology (MRT) plays an important role in the hydrometallurgical processing of dissolved entities in solutions in the mining industry. The status of this industry with respect to sustainability and environmental issues is presented and discussed in this paper, as well as the roles of MRT and ion exchange in metal separation and recovery processes in the mining industry. Examples of MRT separation processes of interest to the mining community are given involving gold and cobalt purification by extraction of trace cadmium, rhenium, and platinum group metals .
Extraction of Molybdenum from Molybdenite Concentrates with Hydrometallurgical Processing
Kaixi Jiang, Yufang Wang, Xiaoping Zou, Lei Zhang, and Sanping Liu
Molybdenite concentrates are usually treated by roasting, but low concentration SO2 pollution is an associated problem. This paper reports on a hydrometallurgical process with pressure oxidation leaching (POX) and solvent extraction that has been recently developed. Compared to the roasting process, the total recovery of Mo increased from 93 percent to 97 percent, and Re from 60 percent to 90 percent when POX and solvent extraction are utilized.
New Technology for Electrorefining of Copper
Andreas Filzwieser and Tim Robinson
New electrorefining technology utilizes a novel manifold electrolyte inlet, which allows improving productivity and production in new and existing tankhouses at high current efficiency and very good cathode quality. Two installation examples—Montanwerke Brixlegg AG, Brixlegg, Austria and Xiangguang Copper, Yanggu, China—demonstrate the use of current densities above 400 A/m² at very high current efficiency.
Z.L. Cai, Y.L. Feng, H.R. Li, X.W. Liu, and Z.C. Yan
This paper presents research on the novel technology of fluidized roasting reduction of low-grade pyrolusite using biogas residual as reductant . The results of the manganese reduction efficiency of the actual experiments were close to those of the fitting model by the verification experiments, indicating that the optimum solution has a relatively high reliability.
Minimization of Copper Losses in Copper Smelting Slag During Electric Furnace Treatment
Pascal Coursol, Nubia Cardona Valencia, Phillip Mackey, Stacy Bell, and Boyd Davis
In the quest to achieve the highest metal recovery during the smelting of copper concentrates, this study has evaluated the minimum level of soluble copper in iron-silicate slags. The authors further consider that under exceptionally well-controlled conditions, a copper content in electric furnace discard slag between 0.55wt.% and 0.7wt.% can be obtained, by minimizing entrained matte and copper solubility in the discard slag.
Thermodynamics of Iron Oxidation in Metallurgical Slags
The state of oxidation of a pyrometallurgical process, given by the partial pressure of oxygen and the temperature, is one of the important properties monitored and controlled in the smelting and refining of iron and the non-ferrous metals. This paper reviews the thermodynamic background for this quantity and examines some empirical methods for its estimation and use. The emphasis is on copper smelting, but the same principles apply to iron, nickel, lead, and zinc processes.
Vacuum Evaporation Technology for Treating Antimony-Rich Anode Slime
Keqiang Qiu, Deqiang Lin, and Xuelin Yang
The vacuum evaporation technology for treating antimony-rich anode slime was developed in this work. Experiments were carried out over temperatures of 873 to 1073 K and residual gas pressure ranges of 50 to 600 Pa. During vacuum evaporation, silver from antimony-rich anode slime was left behind in the distilland in a silver alloy containing antimony and lead, and antimony trioxide was evaporated. The experimental results showed that 92 percent by weight of antimony can be removed, and the silver content in the alloy was up to 12.84 percent. The antimony trioxide content in the distillate was more than 99.7 percent, and the distillate can be used directly as zero-grade antimony trioxide (China standard).
Application of Thermodynamic Models for Better Understanding and Optimization of the Hall–Heroult Process
Pascal Coursol, Gilles Dufour, Jules Coté, Patrice Chartrand, and Phillip Mackey
During the last decade, important improvements have been made in the application of thermodynamic models for studying the molten cryolite system used in the Hall-Heroult process. This approach allows a better understanding and paves the way for furthering developments in bath chemistry and molten metal processing. In this paper, thermodynamic modeling is used to explore the operating windows in the reduction of alumina in molten cryolite. The modeling approach described is considered an important innovation to revisit fundamentals, to constantly re-examine paradigms, and to identify potential modifications in bath chemistry for improving energy efficiency and productivity of modern prebaked Hall Heroult cells.
A Database Approach for Predicting and Monitoring Baked Anode Properties
Julien Lauzon-Gauthier, Carl Duchesne, and Jayson Tessier
The baked anode quality control strategy currently used by most carbon plants based on testing anode core samples in the laboratory is inadequate for facing increased raw material variability. A database approach is proposed in this work to develop a soft-sensor for predicting individual baked anode properties at the end of baking cycle. It is shown that the general low frequency trends in most anode physical and mechanical properties driven by raw material changes are very well captured by the model.. This paper also demonstrates how multivariate latent variable models can be interpreted against process knowledge and used for real-time process monitoring of carbon plants, as well as detection of faults and abnormal operation.
METALLURGY IN A HISTORICAL CONTEXT
Alloying Elements as Chronotechnological Markers for Second and First Century BC Fibulae from Ancient Pannonia
Marianne Modlinger, Ivan Drnic, and Paolo Piccardo
Fibulae as main metal elements of costumes vary significantly in form and shape through time and are the perfect chronological markers of periods and time horizons, helping archaeologists to date associated finds and stratigraphic units precisely. Five Late La Tène fibulae (150-80 BC), typical of the Western Carpathian Basin, were studied in order to achieve information of their composition and manufacture. The presence of certain alloying elements provide a detailed technological and chronological picture of the metallurgical advances in the ancient region of Pannonia.
From Coin to Medal: A Metallurgical Study of the Brazing Drop on a 19th Century Scudo
M. Breda, C. Canovaro, A.F. Miranda Pérez, and I. Calliari
In the past, it was customary to use coins out of circulation as pendants by brazing a peg or a ring on the edge of the coin in order to transform it into a devotional or decorative object. This practice was very common for specimens of the Papal States, especially for silver coin. The metallurgical investigation of a 19th century Scudo described in this paper is aimed to relate the internal structure of the coin to minting technology, with a special focus on the brazing drop, in order to achieve information on the solidification microstructure arising from a strongly non-equilibrium process.
Lead in Ancient Peru: The Curamba Smelter and Lead Sling Bullets
William E. Brooks, Luisa Vetter Parodi, Armando V. Farfan, and David Dykstra
Since the 16th century, the Inca site of Curamba, in southern Peru has been interpreted as a metallurgical center for processing silver ore. Yet, aside from the many shallow pits, interpreted as hornos for smelting silver, there was no physical evidence for the use of huayras or tocochimbos, which were the structures traditionally used for pre-contact silver smelting in the ancient Andes. This paper reports on a geochemical analysis of scoria excavated from the hornos that suggests that non-argentiferous galena was smelted to obtain lead.
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