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By Jeffrey L. Zelms

Environmental issues and how they are addressed -- or not addressed -- by the lead industry in the 1990s will determine the eventual fate of lead mining in both the U.S. and worldwide. Clearly, governmental regulation throughout the West will become harsher. Equally clearly, the industry has? failed to educate the public regarding lead. Instead of public support for a critical mineral, we face widespread public ignorance and paranoia. If we can demonstrate the public interest benefits of the industry, the 1990s will be a decade of continuing growth -- not dynamic growth, certainly, but growth at least comparable to the world economy. If, however, we fail to demonstrate the industry's public interest benefits, the 1990s could mark the beginning of the end of our business.

Jan 1, 1990

By James A. Voigt

"The efficient separation of metal species from aqueous streams by precipitation techniques requires a fundamental understanding of the various processes that occur during precipitation. These processes include particle nucleation, particle growth by solute deposition, agglomerate formation, and agglomerate break-up. The application of the population balance approach has been used to develop a kinetic model that accounts for these competing kinetic processes. The usefulness of the model is illustrated through its application to the precipitation of yttrium hydroxynitrate, YHN. The kinetic parameters calculated from the model equations and system specific solution chemistry are used to describe several aspects of the effect of pH on the precipitation of the YHN. Implications with respect to the simultaneous precipitation of more than one cation type are also discussed through use of example systems. The effects of solution chemistry, precipitator design, and solvent choice are considered.IntroductionThe application of precipitation technologies to the separation of metals from solution is widely used. Regardless of its application, be it in such diverse areas as the preparation of metal oxide powders for use in commercial products or as a unit operation in the removal of trace metals during wastewater clean up, the fundamental processes involved are the same. These processes include: nucleation from solution, either homogeneous or heterogeneous; growth from solution with chemical reaction either in solution or at the precipitate/solution interface; growth by particle agglomeration; and particle break-up by collisional or shear forces. The effectiveness of the operation and the properties of the precipitate formed, or ""quality"" of the product, are determined by the competing kinetics of the different processes. The kinetics of the processes, in tum, are determined by system-specific solution chemistries and the conditions used to carry out the precipitation operation. For example, generally, when system conditions are such that the supersaturation driving force for precipitation is very high, growth species normally do not have the time to organize themselves with a high degree of crystallographic order and the precipitate is amorphous. In this case nucleation rates are invariably extremely high and the primary mechanism for growth is the agglomeration of nuclei. Conversely, when the supersaturation levels for the same system are reduced, the kinetics of the nucleation and growth processes also are greatly reduced, and a crystalline precipitate can be formed, since the growth species have time to order on particle surfaces."

Jan 1, 1996

By David R. Brosnahan

Increased Cu grades due to chalcopyrite-rich ore from The Doe Run Company's new Casteel Mine prompted a program to increase Cu recovery. Preliminary tests indicated that prohibitive quantities of FeS2 float with chalcopyrite. Point counting of mill stream samples showed that locking was not a major problem, although grinding to finer particle size enhanced the floatability of both chalcopyrite and marcasite. Backscattered electron images and microprobe analyses of FeSz minerals revealed the presence of Pb which appears to occur as solid solution in marcasite, and as a sub-micron particulate Pb phase in pyrite.

Jan 1, 1987

By Antti Roine

HSC Chemistry is a widely-used therniochemical tool in the chemical and metallurgical industries and in universities. The main reasons for it's popularity is the easy user interface and the large integrated thermochemical database. This paper summarizes the main properties of the new HSC Chemistry version 3.0, and gives a short review of the new features: Some metallurgical applications with the new features are also presented. HSC Chemistry 3:0 contains seven calculation modules and a thermochemical database with more than 11 ,000 chemical compounds. The new spreadsheet type table editor gives more control to the user, the new graphics routines have fewer limitations and more formatting properties. The capability and speed of calculation routines have also been improved.

Jan 1, 1998

By Karin Soldenhoff

Recovery of uranium in conventional ion exchange circuits, using strong base or weak base resins containing quaternary or tertiary amine functional groups, is based on an anion exchange mechanism. In saline liquors, chloride competes with uranium for the active resin sites and reduces resin loading. This results in significant negative impacts on the IX process in terms of plant throughput and operating costs. In this paper we present the results of a study on the recovery of uranium from an acidic in situ leach liquor containing approximately 9 g/L chloride. A range of resins was tested, and a high capacity strong base resin was identified with significantly enhanced loading compared to conventional resins. Other process-relevant criteria such as loading kinetics and elution efficacy are also discussed. The process developed was successfully tested during a recent ion exchange pilot plant operated in conjunction with a field-leach trial.

By Brian Patrick, Norman Bell, Mark Schoenfield, Thomas Weber, Dietrich Gross

"The reduction of carbon dioxide emissions and the resultant greenhouse gas affect is hampered by the fact that all fossil fuels contain copious quantities of carbon. Process tweaking can keep the amount of carbon dioxide to a minimum but cannot significantly reduce the amount of carbon dioxide generated. The very nature of utilizing fuels requires that they be burned to release the heat required for the various processes. Reduction of metal oxides to manufacture or modify pure metals, generation of power, transportation and many other forms of fuel usage result in much of the generation of man made carbon dioxide. Oxyfuel is a unique contributor to carbon dioxide emissions. While creating higher concentrations of carbon dioxide the total volume of carbon dioxide generated is reduced. This paper will examine the unique characteristics and potential of oxyfuel that make the generation of lower volumes of carbon dioxide possible.Nearly ten years ago a commercial application of oxy-fuel was installed at Jupiter Aluminum Company in Hammond, Indiana. This process was funded and developed by Dietrich Gross CEO. This aluminum remelt facility now runs completely on oxy-fuel and has continuously for over ten years. This has reduced the melt rates to as low as 750 BTU per pound in continuous melting periods."

Jan 1, 2009

By Guo Chen, Yifeng Shi, Xiaobiao Shang, Nanshang Shen, Bangqi Zhang, Jinhui Peng, Junruo Chen

"The energy is introduced directly into the volume of the honeycomb ceramic regenerator due to the complex interaction of microwaves with minerals in microwave gas heating system. A three-dimensional numerical model is developed to simulate the electromagnetic field by solving Maxwell's equations using finite-difference time-domain method. Computational result is presented for the microwave power absorption of the regenerator. Effects of the dielectric constant and the effective loss factor on the microwave power absorption in the regenerator are studied as well. Numerical results show that the heating pattern strongly depends on the dielectric property of the regenerator. The demonstration of the model of electromagnetic field distribution can be applied effectively and efficiently to optimize the fundamental parameters in the microwave heating processing.IntroductionIn recent years, microwave energy has been utilized in many fields, such as food processing, chemical engineering and mineral processing [l]. In contrast to conventional heating, where heat is transferred from a surface to the interior, microwave energy is introduced directly into the volume of minerals due to the complex interaction of the microwave with the mineral. Based on volumetric heating effects, microwave heating has several advantages such as pollution free, rapid heating technique, internal heating, high efficiency over conventional heating [ 1-4]."

Jan 1, 2013

By Roderick Guthrie

Gas injection into liquid steel baths is widely practiced, ever since the early days of Bessemer’s pneumatic steelmaking process. What has not been fully appreciated is the critical role of bubble sizes for delivering higher quality commercial steels than is presently possible. This was first proposed by Prof P. Hayes and his research group. Using a full-scale water model of a typical 4-strand Ladle-Tundish-Mold system, we demonstrate the potential advantages of modifying a typical ladle shroud, to generate microbubbles within the water flowing into the tundish. This is possible by taking advantage of high shear rates and turbulence kinetic energy available in that region. These microbubbles enhanced the removal of “micro-inclusions” (hollow glass microspheres) in the 5–50 micron size range, to the upper surface of the tundish. There, they were absorbed into an overlaying “slag” phase. Accompanying CFD studies confirmed that no microbubbles in the size range generated (500–900 μm), pass through the submerged entry nozzles into the moulds.

By A. Rojo, N. J. Ramirez, J. E. Salgado

"This work aims to characterize the plastics used in a handgrip located in the car interior body in order to improve its design process and be able to predict its behavior when the part is subjected to impact test involving human casualties.Through stress analyses at high speeds and a video camera set up (front and side view), the reduction of area of specimen was obtained from image analysis, allowing to get the stress-strain real curve of the material.Continuing the characterization process a set of impact test was developed, where standard lzod configurations were used in unnotched specimens. From these tests were gotten displacement curves and absorption energy estimations.The proposed testing procedure allowed the acquisition of force and displacement data through time at various strain rates which are indispensable for the characterization of dynamic events. Using a specimen with a special configuration has shown a more detailed dynamic behavior resulting into more accurate numerical analyses within the design process.IntroductionIn the design process, one of the many analyses which take place is the impact test of the designed part. Nowadays there are many software capable to do these kind of analysis and each industry use the one they think it is convenient for them, but also the selected software has mathematic models that help to find the solution and the simulation of the case of analysis. These are not the only considerations that a company has to take into account, other one is the type of information and data necessary to feed the software. For this study we are going to focus on the acquisition of these data.The mail reason of this work is that generally the supplier gives the card of the material with all the characteristics and information requested by the buyer, but all of that information is acquired by standard methods, but it is inconvenient when the materials are polymers."

Jan 1, 2011

By Jean-Pierre Birat, Ana-Maria Iosif, Denis Ablitzer, Olivier Mirgaux

"Integrating environmental considerations into the product traditional process design is now the major challenge for steel industry. Life Cycle Assessment (LCA) is nowadays considered as an appropriate method for assessing environmental impact and selecting new technologies to reduce CO2 emissions for steel industry.In this paper we propose a new methodological concept which combines LCA thinking with process simulation software in order to carry out the life cycle inventory of classical steelmaking process.Using Aspen PlusTM software, a physicochemical model has been developed for the integrated steelmaking route. This model gives the possibility to carry out life cycle inventories for different operational practices in order to optimise the use of energy, to calculate CO2 and other emissions and to control the mass and the heat balances of processes.It is also shown that such approach can be used to design and assess new technologies for steelmaking without large industrial application.IntroductionDuring recent years, it was recognised that CO2 emissions are the major factor of the global warming effect. In order to meet Kyoto requirements, the steel industry is embracing the challenge of sustainable development by improving its competitiveness and economic success while reducing its environmental impacts. Integrating environmental considerations into the traditional product design process, for powerful eco-efficiency, is now one of the major priorities for steelmakers.The European Steel Industry has measured up to this challenge by creating ULCOS (Ultra Low CO2 Steelmaking) consortium that has taken up the mission to develop breakthrough steelmaking process with the potential to reduce CO2 emissions (Eurofer, 2005). In order to develop technologies to reduce emissions, it is necessary to assess the environmental impact of the classical steelmaking route (coke plant, sinter plant, blast furnace, basic oxygen furnace, continuous casting and hot rolling)."

Jan 1, 2009

By B. C. F1intoff, R. G. Bradburn, E. Groiss

"The concentrator at Brenda Mines Ltd. treats a copper - molybdenum porphyry ore with current head grades of 0.185% Cu and 0.036% Mo. The consistently low head grades provided the driving force to explore methods of improving plant productivity. Computer based process control was recognized as one means of addressing this objective. Over the period from 1974 to 1982 a control system evolved which now extends to every area of the mill. Control strategies are built on elements of classical, modern and rudimentary expert control. In addition, the control system has often served as a catalyst for other technological developments. The economic returns associated with the system are very significant and it has played an important role in the mine's survival in times of poor metal markets. This paper presents an overview of the computer control system at Brenda.PreambleOne can scarcely avoid picking up a trade magazine or newspaper today without seeing some reference to technology and its potential impact on North American business. _A recurring theme is the need to apply technology to raise our standard of plant automation in the manufacturing and process industries. The general thesis of these articles has been concisely captured in the mutually exclusive set:AUTOMATE or EMIGRATE or EVAPORATEProcess control is one form of automation that has been successfully exploited by various sectors of these industries. In minerals and metal processing the wide scale adoption of process control technology has, until recently, been largely limited to a few companies - most of whom have a history in the area dating back to the early 1970’s. However, there is definitely an increased and much broader interest in process control as a technology which can improve performance, productivity and profit.The economic hardships that were visited on the mining industry in the early 1980's are not easily forgotten. It is the authors' conviction that the mining industry must move to implement proven technology, in particular process control, in order to be well postured for the next (inevitable) down cycle.In pursuing the technical and trade literature, one can discover a number of example of the successful utilization of process control systems in mining and related applications. In the text which follows, the authors describe the process control efforts undertaken in the Brenda Mines Ltd. concentrator."

Jan 1, 1989

By J. W. Holzenthaler

Teams continue to play a major role at the Phelps Dodge Mining Company El Paso Operations, especially during the present time of low copper prices. The El Paso Operations' teams have taken the initiative during this copper market downturn and have helped reduce operating costs significantly. Because of this, Phelps Dodge El Paso Operations has continued to grow within the team process by creating a total, non- exempt salaried workforce. In the last year alone, the El Paso Operations have implemented three major initiatives to accommodate the team process. The first was the creation of "guiding principles", a policies and procedures handbook. Second was the "zero and beyond" safety initiative. Third was team compensation. In addition, the Copper Products Company has now adopted a work-team environment, following the lead of the refinery.

Jan 1, 1999

By Nathaniel R. Quick

"Nd: YAG, KrF excimer, and Cu-vapor lasers are used in air to synthesize conductors and semiconductors as a second phase in silicon carbide and aluminum nitride. Conductor resistivities as low as 104 O-cm are formed in these substrates; the resistivities for the untreated substrates range from 10 11to 1014 O-cm. The silicon carbide conversion is relatively independent of wavelength while the aluminum nitride conversion shows a dependence on wavelength over the range 248 nm to 1064 nm. Silicon carbide conductors, evaluated over the range 15 K to greater than 300 K, exhibit metal like conductivity; resistivity increases with temperature. Silicon, carbon, and oxygen are identified as the principal chemical species associated with the conductor in SiC substrates while aluminum, nitrogen, and oxygen are identified as the principal chemical species associated with the conductor in aluminum nitride substrates. The silicon carbide system, which has the less complex phase diagram, is evaluated in more depth to explain the synthesis mechanism. Oxygen was principally on the surface and increasing SiC conductivity is associated with decreasing spacing between 5 µm, or less, diameter carbon globules. This technology is proposed as a replacement for metallization in electronic packages, sensors and devices. INTRODUCTIONCeramics are commonly used for multichip module, hybrid and multilayer electronic packaging; semiconductor device and sensor applications because of the insulating, conducting, semiconducting, or superconducting properties that these materials possess (1,2) The majority of ceramics, however, have not been known to exhibit conductive or semi conductive properties when exposed to rapid thermal heat processing. A ceramic and process which through selective conversion can combine two or more of these electrical properties to eliminate the need for metallization is of interest to both the commercial and military sectors."

Jan 1, 1994

By Kenneth L. Driggs

The Environmental Protection Agency's Clean Air Act of .1970 provided the driving force for the current Magma Smelter configuration. The historical and technical perspectives of those process developments are reviewed. Innovations in procedures and equipment have allowed compliance with the requirements of the regulating authorities. The wet scrubbing of converter gasses and the monitoring of converter operations by a controlling foreman are two of the major contributors to these successes. The Clean Air Act Amendments of 1990 have posed many new concerns for all U.S. industry, including the few (seven) primary copper smelters remaining. Future concerns include tightening the sulfur dioxide ambient standard from the current three-hour averaging period to one hour"

Jan 1, 1992

By Ted H. Eyde

Natural Zeolites are a less expensive and in certain applications a superior alternative to organic ion exchange resins. Mining and metallurgical waste streams are difficult to treat because the effluents which contain potentially valuable heavy metals such as copper, lead, and silver are often highly acidic and contain significant quantities of suspended solids. Under rigorous operational conditions, certain natural zeolites can remove the metals, which if desired can be recovered by either elution or conventional smelting techniques. There are significant differences in cation exchange rate, selectivity and capacity as well as resistance to either high or low pH, blocking cations and tolerance to elevated or depressed temperature and pressure not only between different zeolite minerals but between the same mineral from different deposits. Applying natural zeolites to the treatment of mining and metallurgical waste streams depends on matching the specific zeolite to the effluent by characterization of the zeolite minerals.

Jan 1, 1993

By K. A. Dudley

Basic solvent extraction theory indicates that pH initiates the basis of an oxime's metal complex formation and therefore its selectivity toward certain metal species. The recommended optimum pH for some of the commercial copper reagents is in a range that should maximise copper loading of the oxime. However, this pH range also tends to maximise iron(III) loading under certain operational conditions resulting in low selectivity values. Recent operational parameters at Girilambone Copper Company have highlighted some of these conditions that have a major influence on the oxime's selectivity for copper over iron(III) in the leach solutions. The result is that the pH for maximum copper extraction is no longer within the optimum range to maximise oxime selectivity. Therefore, specific copper and iron(III) pH isotherms have been determined on-site for the changing leach solutions that are fed to the solvent extraction plant in order to optimise oxime selectivity. The influences of solvent extraction plant configurations are also discussed as a controlling parameter.

Jan 1, 1999

By V. Jiricny

There is a growing need to process galvanized steel scrap from automobiles, etc., in order to remove the zinc coating that otherwise causes problems in remelting of the scrap in electric arc furnaces. One approach that has moved to the pilot plant stage is that of Metal Recovery Technologies, Inc., of East Chicago (MRI). That company leaches the zinc fiom the scrap with a sodium hydroxide solution. The leached and washed scrap can then be returned to the steel industry. What is left is a sodium hydroxidelzincate solution which must be processed to recover the zinc and the NaOH. Presently, this is done by MRI using electrodeposition on planar electrodes at moderate current density and the resulting zinc is in the form of fine powder which is hard to process into, say, zinc for galvanizing. MRI has supported an investigation of a novel electrode, the spouted bed electrode (SBE), for zinc electrodeposition. In laboratory cells, zinc particles with low porosity have been grown up to 3mm in size. Microanalysis of the deposited zinc showed low level of impurities. DC energy consumption values were usually in the range of 2-2.5 kWg which is well below the energy consumption of the existing cells (and of present-day cells for electrowinning from acid sulfate electrolytes). These results were achieved at current densities (few thousand A/m2) that are much higher than possible with conventional electrodes. Discussion is provided of the scale-up of the cell to a commercial scale.

Jan 1, 1998

By Adolf Mikula

Lead-tin solders are commonly used in electronic packaging due to their unique combination of electrical, chemical, physical, thermal and mechanical properties. Since it is known that lead and lead containing alloys cause great environmental concern and health hazards it is necessary to replace lead in solder materials. Besides the environmental concerns new technologies in electronic packaging require new and improved solders. In most cases the new solders will consist of ternary or quarternary alloy systems, the main component will be tin or indium and the second element could be bismuth, silver, copper and gold and to improve certain properties a third element will be added. For a third element zinc, nickel, antimony and aluminum can be considered. This report will concentrate on solders containing zinc as an environmental safe element.

Jan 1, 2003

By G. Laird, N. B. Gray, N. Lawson

"Photographic, video, laser, hot film and conductivity methods are used in the experimental study of gas-liquid flows. A discussion of their capabilities and limitations are given in this paper illustrating the wide range of phenomena that can be studied. Most of these methods are limited to physical models at room temperature with transparent fluids, although they can be extended for use with opaque and hot fluids. A number of these techniques have been used by the GKW CRC in studies on industrial plants and their usage is increasing although a number of technical difficulties still need to be overcome. An in-depth discussion of the laser doppler anemometry (LDA) and particle image velocimetry (PIV) methods is given with experimental results on the flow field of an air plume in water based on advanced development of the techniques and studies carried out at the GKW CRC. The LDA method provides high resolution data on the velocity profiles, while the PIV method provides an overall view of the complex flow structure occurring at the gas-liquid regions. These two methods complement each other in providing experimental data for validating numerical models and exploring the complexities of multi phase flows.IntroductionThe injection of gases into melts is an important operation in the metallurgical industry. It is used in converters, anode furnaces, blast furnaces, ladles, bath smelters, zinc fumers and many other smelting processes. In many of these processes, the gas is injected into a molten bath resulting in the formation of bubbles that promote reaction, mixing, alloying and heat transfer. The study of gas-liquid systems presents enormous challenges to the researcher due to the complexity of the mathematical and physical modelling which require innovative numerical and experimental skills."

Jan 1, 1996

By Eva B. Kisvarsanyi

An Early Proterozoic orogenic terrane of metasedimentary and metaigneous rocks underlies Nebraska, Kansas, and Missouri. Middle Proterozoic epizonal terranes of anorogenic granite and rhyolite, a known metallogenic province partly exposed in southeastern Missouri, overlap the orogenic terrane on the south. These Proterozoic terranes, covered by less than 1,000 meters of Phanerozoic strata, contain a virtually untapped source of mineral wealth and are one of the last frontiers for geologic exploration in the continen-tal United States. Petrographic study of subsurface samples is a powerful tool in the identification of favorable host rocks for a variety of ore deposits.

Jan 1, 1987