Research progress in biohydrometallurgy of rare metals and heavy nonferrous metals with an emphasis on China

In the past decade, progress in the field of biohydrometallurgy had been significant. A total of 17 novel biomining microorganisms were discovered, and eight copper heap bioleaching plants and 11 gold biooxidation plants were established or expanded. In this review, it was summarized the physiological properties of the newly isolated biomining microorganisms and three novel microbial ecological methods for studying microbial community dynamics and structure. In addition, biohydrometallurgy research on rare metals such as uranium,molybdenum, tellurium, germanium, indium, and secondary rare metal resources, as well as heavy nonferrous metals such as copper, nickel, cobalt, and gold has been reviewed, with an emphasis on China. In future, further studies on bioleaching of chalcopyrite, rare metals, secondary resources from waste, and environmental pollution caused by resource utilization are necessary.     

Solidification science in cast MMCs: The influence of merton flemings

The solidification science of cast metalmatrix composites (MMC) evolved as a subset of the broad field of solidification of monolithic alloys pioneered by Merton Flemings and his students. As a result of advances in solidification, the cast MMC field has evolved from its early incarnation—employing empirical research to engineer novel materials using versatile and cost-effective casting techniques—to using solidification-science-based approaches to tailor advanced materials for application-specific needs. The current and emerging applications of cast MMCs in a variety of automotive, aerospace, electronic packaging, and consumer-good industries exemplify the maturity of the field and the materials. Innovations in composite-forming techniques and efforts at wider industrial acceptance of MMCs will undoubtedly continue. However, the scientific principles underlying the solidification microstructure evolution that governs the composite properties have become well established, to a great extent, due to Flemings’ early, pioneering work on monolithic alloys and some of his more recent studies on solidification of reinforced metals. This paper reviews some aspects of solidification of discontinuously reinforced cast metals that owe their current understanding to Flemings’ contributions, in particular, the scientific understanding of macro- and microsegregation, fluidity and rheology of multiphase slurries, and stircasting, semi-solid casting, and preform infiltration. Current research to develop and test prototype components made from cast composites, including Al-flyash, Cu-graphite, Al-graphite, Al-alumina, and SiC-Al, is also presented, along with directions for future research. For more information, contact P. Rohatgi, University of Wisconsin-Milwaukee, Center for Composites, Milwaukee, Wisconsin 53201; prohatgi@uwm.edu.     

Nickel and chromium cycles: Stocks and flows project part IV

Nickel and chromium are essential ingredients in alloys increasingly important for energy-efficient, environmentally friendly modern technology. Quantitative assessment of the flows of these metals through the world economy from resource extraction to final disposal informs resource policy, energy planning, environmental science, and waste management. This article summarizes the worldwide technological cycles of nickel and chromium in 2000. Stainless steel is the major use of these metals, but they serve numerous other special needs, as in superalloys for high-temperature service, as plating materials, and in coinage. Because they are used primarily in alloys, novel recycling issues arise as their use becomes more widespread. “... the great New York and St. Louis double track, nickel plated railroad...” — Norwalk, Ohio, Chronicle 10 March 1881 announces arrival of surveyors for the future Nickel Plate Railway “Later [1911] I formed an alloy of Iron and Chromium, which showed remarkable resistance to rust and tarnish ... [It was] rediscovered by an Englishman named Brearley, in 1914.” —Elwood Haynes to Stephen F. Roberts, 17 January 1925     

On the wave propagation of concentration hydrogen disturbances in palladium

The mechanisms of the origin of moving hydrogen concentration inhomogeneities recently discovered in the Pd—H system are discussed. An exact wave solution to the nonlinear equation of diffusion for hydrogen in metals has been found. On the basis of this solution and approximate solution found earlier, a conclusion has been made that the basic reason for the appearance of moving inhomogeneities can be the interaction (attraction) of hydrogen atoms dissolved in the metal rather than internal “hydrogen-induced” concentration stresses.     

Soda-fuel metallurgy: Metal ions for carbon neutral CO<Subscript>2</Subscript> and H<Subscript>2</Subscript>O reduction

The role of minerals in biomass formation is understood only to a limited extent. When the term “photosynthesis—CO₂ and H₂O reduction of sugars, using solar energy”—is used, one normally thinks of chlorophyll as a compound containing magnesium. Alkali and alkaline earth metals present in leaf cells in the form of ions are equally essential in this solar energy bioconversion coupled with nitrogen fixation. Application of some of these principles can lead to artificial carbon-neutral processes on an industrial scale close to the concentrated CO₂ emission sources.     

General concept of surface structure and elasticity of liquids

The concept of generalization says: of any two related concepts, such as A and B, A is a “generalization” of concept B if every instance of concept B is also an instance of concept A, but not contrary. So, animal is a generalization of bird since a bird is an animal, and there are many other animals. In this view (and to start) consider a more complicated example: any car has a minimal set of vitally necessary attributes: 1—energy supply (storage), 2—engine, 3—framework, 4—transmission, 5—propulsive device (wheels, tracks ...), 6—command center (a person or computer). Actually, this obvious set has a universal character and may be generalized for all self-moving devices with some proper variations in point (5), e.g. an airplane’s propeller, submarine’s screw and so on. Amazingly, this set of vital attributes is also suitable for many living creatures, at least for mammals, birds, fish and possibly for some others. For instance, it would be essentially the same for humans, cats, dogs, squirrels ... and so on, if: 123—stomach, 23—heart, 3—spine, 4—nerves and muscles, 5—paws, 6—brain.     

Progress in application of rare metals in superalloys

Rare metals play an important role in development of superalloys. Over the last two decades, the application of the rare metals in superalloys has achieved progress significantly. They present multi-beneficial effects for strengthening the matrix and the c0phase, increasing the lattice misfit, cleaning the grain boundary, improving the carbides and eutectics, refining the grain, stabilizing the oxidation film, etc., so that the elevated temperature rupture life and elevated temperature oxidation resistance are improved significantly, leading to a broad application in the superalloys. In order to meet the higher demand for better superalloys in the future, more intensive research is necessary on the effects of the rare metals on the superalloy, and especially on the combination effect of various rare metals and mutual influence among them. Utilization of the computational materials science and combinatorial high throughput experiment will be of importance in application of rare metals in superalloys.     

Using Thermal Spray and Laser Micromachining to Fabricate Sensors

The use of thermal spray to fabricate sensors directly onto engineering components is an emerging technology. The capabilities for sensor fabrication are considerably enhanced with the use of laser micromachining, in which feature sizes as small as 15-20 μm can be achieved. Such feature sizes are required for a variety of sensors, including strain and heat flux sensors, thermopiles and microheaters. Ultrafast lasers—lasers with pulse durations ≲1 ps—are particularly well suited for the multimaterial/multilayer processing required to fabricate sensors from materials deposited using thermal spray. In this work, the key issues associated with laser micromachining of thermal spray coatings for sensor applications are presented. Both resistive strain gages and microheaters are discussed in detail as representative sensor designs that require the fine feature and linewidth capability that laser micromachining provides, including details of their fabrication and practical design restrictions. This article summarizes with recommendations for future work.     

Hydro- abrasive jet machining modeling for computer control and optimization

Use of hydro-abrasive jet machining (HAJM) for machining a wide variety of materials—metals, poly-mers, ceramics, fiber-reinforced composites, metal-matrix composites, and bonded or hybridized mate-rials—primarily for two- and three-dimensional cutting and also for drilling, turning, milling, and deburring, has been reported. However, the potential of this innovative process has not been explored fully. This article discusses process control, integration, and optimization of HAJM to establish a plat-form for the implementation of real-time adaptive control constraint (ACC), adaptive control optimiza-tion (ACO), and CAD/CAM integration. It presents the approach followed and the main results obtained during the development, implementation, automation, and integration of a HAJM cell and its computer-ized controller. After a critical analysis of the process variables and models reported in the literature to identify process variables and to define a process model suitable for HAJM real-time control and optimi-zation, to correlate process variables and parameters with machining results, and to avoid expensive and time-consuming experiments for determination of the optimal machining conditions, a process predic-tion and optimization model was identified and implemented. Then, the configuration of the HAJM cell, architecture, and multiprogramming operation of the controller in terms of monitoring, control, process result prediction, and process condition optimization were analyzed. This prediction and optimization model for selection of optimal machining conditions using multi-objective programming was analyzed. Based on the definition of an economy function and a productivity function, with suitable constraints relevant to required machining quality, required kerfing depth, and available resources, the model was applied to test cases based on experimental results.     

Advances in the manufacturing,types, and applications of biosensors

In recent years, there have been significant technological advancements in the manufacturing, types, and applications of biosensors. Applications include clinical and non-clinical diagnostics for home, bio-defense, bio-remediation, environment, agriculture, and the food industry. Biosensors have progressed beyond the detection of biological threats such as anthrax and are finding use in a number of non-biological applications. Emerging biosensor technologies such as lab-on-a-chip have revolutionized the integration approaches for a very flexible, innovative, and user-friendly platform. An overview of the fundamentals, types, applications, and manufacturers, as well as the market trends of biosensors is presented here. Two case studies are discussed: one focused on a characterization technique—patch clamping and dielectric spectroscopy as a biological sensor—and the other about lithium phthalocyanine, a material that is being developed for in-vivo oxymetry.     

Estimating U.S. uranium reserves

This article presents information on the Energy Information Administration’s (U.S. Department of Energy) annual estimates of U.S. uranium reserves. Encompassed is information for year-end 1997’s uranium reserves, which were estimated by employing numerous resources. Author’s Note: In this article, uranium reserves are discussed for the $30, $50, and $100 per pound forward-cost categories. Forward costs are determined based on anticipated future operating and capital expenditures incurred in the recovery of uranium ore materials. Reserves are cumulative; the quantity at a given level includes all reserves at lower costs. Thus, reserves for the $50 per pound category include the $30 per pound totals, and the $100 per pound category includes totals from the other two categories. Uranium reserves that could be recovered as a by-product of phosphate and copper mining are not included. (Sources for the data presented here are: the EIA, Office of Coal, Nuclear, Electric and Alternate Fuels, based on industry conferences, DOE Grand Junction Projects Office data files, and EIA form EIA-858, Uranium Industry Annual Survey 1997.) Luther L. Smith earned his B.A. in geology at the University of North Carolina at Chapel Hill in 1962. He is currently a geologist with the Energy Information Administration, U.S. Department of Energy.     

Reactions of small molecules on gold single crystal surfaces

Supported heterogeneous gold catalysts (also called “real” catalysts) have been far more studied than gold single crystal surfaces. However, the surface science approach — fundamental studies of chemistry on well defined gold surfaces under controlled conditions — is extremely important, as it contributes to the understanding of the reaction mechanisms and of the nature of active centers, which allows a better knowledge of the “real” systems. This paper presents a brief overview concerning the work carried out on gold single crystal surfaces from 2004 until recently. Results on the reactions of several molecules on gold surfaces, experimental and computational (DFT) are discussed.     

Electrodeposition and properties of bismuth alloys with low-melting metals

The electrodeposition of bismuth alloys with indium, lead and cadmium from trilonate baths is investigated. X-ray diffraction and scanning electron microscopy are used to determine the structure of the prepared alloys deposited under various electrolysis conditions. The electrocrystallization conditions of two-phase alloys—mechanical mixtures, are determined. The electrochemical alloying of bismuth coatings with low-melting metals is conducive to refining the grain structure, smoothing the surface relief, and increasing their acidic corrosion resistance. Original Russian Text ? V.V. Povetkin, T.G. Shibleva, 2006, published in Zashchita Metallov, 2006, Vol. 42, No. 5, pp. 557–560.     

Toward new technologies for the production of lithium

The lightest of all metals, lithium is used in a variety of applications, including the production of organolithium compounds, as an alloying addition to aduminum and magnesium, and as the anode in rechargeable lithium ion batteries. All of the world’s primary lithium is produced by molten salt electrolysis. This article reviews the current technology for lithium extraction and assesses the prospects for change. Georges J. Kipouros earned his Ph.D. in mining and metallurgical engineering at the University of Toronto. He is currently head of the Departiment of Mining and Metallurgical Engineering of DalTech—Dalhousie University. Dr. Kipouros is also a member of TMS. Donald R. Sadoway earned his Ph.D. in chemical metallurgy at the University of Toronto in 1977. He is currently a professor of materials chemistry in the Department of Materials Science and Engineering at Massachusetts Institute of Technology. Dr. Sadoway is also a member of TMS.     

Superplastic Forming 40 Years and Still Growing

In late 1964 Backofen, Turner & Avery, at MIT, published a paper in which they described the “extraordinary formability” exhibited when fine-grain zinc-aluminum eutectoid (Zn 22 Al) was subjected to bulge testing under appropriate conditions. They concluded their research findings with the following insightful comment “even more appealing is the thought of applying to superplastic metals forming techniques borrowed from polymer and glass processing.” Since then their insightful thought has become a substantial reality with thousands of tons of metallic sheet materials now being superplastically formed each year. This paper reviews the significant advances that have taken place over the past 40 years including alloy developments, improved forming techniques and equipment, and an ever increasing number of commercial applications. Current and likely future trends are discussed including; applications in the aerospace and automotive markets, faster-forming techniques to improve productivity, the increasing importance of computer modeling and simulation in tool design and process optimization and new alloy developments including superplastic magnesium alloys. This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati, OH, October 15-19, 2006.     

稀土元素在金属材料中的作用与机理

该文作者从１９６１年开始进行稀土元素在铁基、镍基、铜基、铝基等约百个２～４元金属溶液体系的热力学、相平衡及在２０多个金属材料（包括稀土－铁超磁致伸缩材料）中的作用与应用研究，该文依据作者所在科研组的研究成果并参考一些文献，说明了稀土元素在金属材料中的作用和机理     

Four approaches to improve the tensile ductility of high-strength nanocrystalline metals

Until recently, the reported tensile ductility of high-strength nanocrystalline metals was disappointingly low. This article presents a brief overview of the latest encouraging progress in developing nanocrystalline metals that offer not only gigapascal strength but also decent ductility. Four different approaches have been identified in recent studies, including some of the author’s experiments. These efforts are interesting extensions of previous/parallel success in optimizing the tensile properties of bulk nanostructured/ultrafine-grained metals. This paper was presented at the International Symposium on Manufacturing, Properties, and Applications of Nanocrystalline Materials sponsored by the ASM International Nanotechnology Task Force and TMS Powder Materials Committee on October 18–20, 2004 in Columbus, OH.     

Properties of metallic cements formed upon the interaction of mechanochemically synthesized copper alloys with liquid gallium and its eutectics: Interaction of Cu/Bi composites with liquid gallium

Atomic force microscopy and scanning electron microscopy were used to study the structure of metallic cements that are formed upon the interaction of Cu/Bi mechanocomposites with liquid gallium at room temperature. It has been established that the intermetallic compound CuGa₂, which is the basic component of this metallic cement, is formed as tetragonal crystals 1–4 μm in size with a characteristic layeredspiral growth. The second phase—bismuth—is adsorbed at the growth steps in the form of disperse formations 70–250 nm in size; local bismuth accumulations of micron size are also observed. It is shown that in the metallic cement that is formed at room temperature regions of incompletely reacted Cu/Bi composite are retained.     

The status of utah coal in global resources

Coal resources have had a historical effect on the development of Utah and a far-reaching influence in the western expansion of the United States. Although Utah’s production is just more than two percent of the total national production, the resource quality is higher than most other coal fields in the United States. Coal production surpassed 25 million tons in 1995 and has increased in recent years. In this article, the specific properties of Utah’s various coal fields are discussed in terms of marketability, mining difficulty, and transport to markets. The broad spectrum of Utah’s coal production—past, present, and potential future growth—is reviewed through distribution and coal usage data spanning a ten-year period. Editor’s Note: Although JOM style dictates the use of metric units of measurement, this article retains U.S. customary units to conveniently reflect the commodities standards employed in the coal industry. F.R. Jahanbani earned his M.S. in business management at Brigham Young University in 1967. He is currently a senior energy specialist at the Department of Natural Resources, State of Utah.