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By J. P. Downey, T. Salisbury, M. Berlin, E. Rosenberg, G. Pinson, R. Christianson, K. Gleason, W. Gleason, S. Davis

"The Center for Advanced Mineral and Metallurgical Processing is developing membrane production technology based on autocatalytic reduction of palladium from solution onto a unique, porous substrate. Surface membranes and catalytic structures are critically important to applications that range from hydrogen purification membranes to petroleum refining. Autocatalytic reduction processes represent a cost effective method of producing stable surface layered structures that have good working lives. These attributes are particularly important in the production of palladium alloy purification membranes used in hydrogen production. Although considerable research has investigated the interaction of hydrogen and palladium alloys, the mechanisms in play while the membranes form are not well understood. Preliminary research has identified three distinct deposition mechanisms and it appears that substantial control over the resulting membrane is possible.IntroductionPalladium-based membranes separate hydrogen from other gases because hydrogen is uniquely soluble in and readily passes through bulk palladium. As currently produced, palladium-based membranes are expensive and have short service lives. These circumstances are due in part to the lack of a complete understanding of palladium or palladium alloy deposition. The Center for Advanced Mineral and Metallurgical Processes (CAMP), in collaboration with the Metallurgical and Materials Engineering Department at Montana Tech and the Chemistry Department at the University of Montana, is engaged in the development of new methods and materials for hydrogen purification membrane production.In membrane production, the palladium requirement depends on substrate surface properties such as surface chemistry, porosity, and roughness. Thin, defect-free membranes have been successfully produced on substrates of porous glass, alumina, and stainless steel. However, the differences in the thermal expansion coefficients of palladium membranes and porous glass or alumina substrates cause problems at operating temperatures. The use of stainless steel substrates is advantageous because stainless steels have thermal expansion coefficients similar to that of palladium and they are stable at the required operating temperatures (Wicke, E., Brodowsky, H. and Ziichner, H. ). Stainless steel is also readily available and relatively inexpensive."

Jan 1, 2012

By M. Kawakami

In relation to the designing of a new-type blast furnace, the reaction of carbonaceous materials with C02 is expected to occur at as low temperature as possible. In order to get a highly reactive carbonaceous material at low temperature, the reaction kinetics was investigated by measuring such quantities as the reaction rate from weight loss, the amount of CO adsorption and specific surface area by BET method. The reaction rates were large in the order of the Bintyo char, metallurgical coke, graphite and glassy carbon. If the rate was converted to the rate per unit area, however, those of the Bintyo char was smaller than that of graphite. Thus, it is suggested that the rate of the Bintyo char is influenced by the pore diffusion of C02. The rate had a positive relation with the amount of CO adsorption, showing that the rate determining step would be the desorption of CO from the active side on the surface. The rate independent of surface area was derived, combining al\ the obtained data.

Jan 1, 2003

By L. J. Lutz

The U.S. Bureau of Mines has developed an electrorefining process to recover Ni, Co, Cr, and other metals from mixed and contaminated superalloy scrap. The superalloy scrap is cleaned then directly electrodeposited as a Ni -Co deposit. The process recovers approximately 90 pct of the Ni-Co available from the scrap as a 99t pct pure Ni-Co alloy. During electrorefining the electrolyte undergoes a purification process which results in Cr and other refractory metals reporting to the purification residue. Operating data is given for a 3-L compartmented electrolytic cell. Techniques for the removal of Fe, Cr, and trace impurities from the recycled electrolyte are outlined. The economics of a facility producing 15 mt/d of a Ni-Co alloy are also discussed.

Jan 1, 1993

By V. Ramachandran

In view of the increasing environmental regulations that have been promulgated in the last 30 years, non-ferrous smelters and refineries have learnt to handle effectively the process waste streams that need to be bled from the system for impurities' control The cations of concern are copper, lead, zinc, cadmium, mercury, thallium, nickel, silver, sodium and potassium. Anionic species of arsenic and selenium also need to be addressed, Sulfates and chlorides-not a major concern at present-have come under scrutiny in the recent past. The current paper reviews several treatment options with reference to a) types of waste streams processed b )process chemistry c)discharge options and recovery of treated water and d) sludge disposal The long term goal of any smelter and/lor refinery should be to achieve zero liquid discharge from the plant. Methods to obtain zero discharge are discussed.

Jan 1, 2003

By A. Slotwinski, R. E. Barry, M. M. Menon, P. T. Spampinato

"A coherent FM laser radar based sensor for remote metrology of plasma facing material surfaces in a fusion reactor is described. The sensor is capable of 3-D mapping of surfaces, based on a series of precise range measurements from large distances (up to 20 m). Other features include the ability to operate under adverse environmental conditions involving very high gamma radiation (3xI04 Gy/hr), ultra-high-vacuum (<I0-5 Pa), and high temperature (200°C). The paper describes the basic principles of the sensor, together with experimental results obtained with the sensor. The ability of the sensor for remote rendering of ""visual quality"" images without the need for any external illumination is also illustrated.IntroductionMeasurement of the features of large area surfaces (-1500 m2) to sub-millimeter accuracy, from relatively large distances (20 m), is necessary in the case of the International Thermonuclear Experimental Reactor (ITER -a 1500 MW fusion reactor that is currently in the design phase). Furthermore, the measurements may have to be performed after the reactor is temporarily shut down. During such shut-downs, the ITER in-vessel environment will be highly radioactive due to neutron activation of the reactor wall (gamma radiation field of 3xl04 Gy/hr), the vessel will be maintained under ultra-clean vacuum conditions (<10-5 Pa), and the plasma facing surfaces will be maintained at elevated temperature (200°C). Therefore, the precision measurements must be conducted remotely, and because of the large dimensions of the fusion reactor and the limited number of access ports, the measurements must be done from large distances. The reactor vessel is a large toroid. Fig. 1 shows the cross section of the toroidal vacuum vessel, and the location of the metrology probe. Because of the very large surface area involved, fast scanning capability is also needed to reduce the reactor down-time."

Jan 1, 1997

By Jean-Christophe Gebelin, Mark Jolly, Samantha Jones

"The de-waxing process in investment casting is truly a black art which is carried out in a black hole - the autoclave. The process involves exposing wax, coated by a porous ceramic shell, to steam at a pressure of 10 bar and a temperature of about 180°C. The processes which then occur are truly multi-media and multi-physics. Steam condenses in the porous ceramic, wax melts and flows, the shells expand and sometimes crack. Why the shells crack is one of the most difficult questions asked in the industry.Modelling and validating the de-waxing process is not simple. The IRC at the University of Birmingham is attempting to model this process using Physica+ a code developed in the UK. This paper will present the latest results in this attempt to model one of the casting industries most intractable problems.IntroductionThe de-waxing process using an autoclave involves the following physical phenomena:· Flow of the steam in the autoclave;· Heat transfer from the steam to the wax, possibly through the shell;· Melting and flow of the wax.At the same time, other phenomena may occur, such as the flow of the steam through the shell, the condensation of the steam on the shell surface and on the wax pattern surface, the flow of wax the through the shell, etc ...This shows how complex the de-waxing process is from a physical point of view. The main defect that appears during this process is the cracking of the shell. Previous modelling work carried out by Snow [1] has shown that it is possible to predict the stress in the shell, making numerous assumptions. In this paper, the modelling to predict the state of stress in the shell that is currently in development at the University of Birmingham is presented together with the presentation ofthe physical phenomena to model and the assumptions used. The parameters that are needed in such models will also be discussed, and some experimental work undertaken at the moment presented."

Jan 1, 2001

By Merete Tangstad, Ragnar Tronstad

Ferromanganese production in electrical furnaces is quite an old process. However, as the furnaces are getting bigger, the requirements of cost, yield, product quality, emissions and security are raised. With the increased expectations, the fundamental knowledge must follow. Within the last 25 years there has been a great effort both in the industry as well as the academic environment to push the limits of this process. This article will show some examples of improvements within fundamental data, reaction mechanisms and emissions over this time period.

Jan 1, 2014

By A. Lakschevitz

The Amazon region offers a large potential for gold extraction but its peculiar characteristics such as heavy rains, lacking of roads and general infra-structure, nature of the ore deposits, etc.. do require special care in plant design. REMETÁLICA has developed a know-how is designing leaching plants which have been demonstrated to be profitable under those tropical weather conditions. The solutions adopted are related to general process route, leach liquor distribution and flow pattern, conditioning of solids and effluent treatment. These plants, now operating in South America countries, demonstrate the success for the technology developed. A tipical plant with 800 t/day ore processing capacity, may require an investment of US$ 1.200.000,00, arid have? a pay back period of a few months, depending on ore grade.

Jan 1, 1989

By Kenneth L. Driggs

The Environmental Protection Agency&apos;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 Kenneth L. Driggs

The Environmental Protection Agency&apos;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 B. I. Hop

The f10wfield set up by the standard Hydro gas purging unit has been predicted by a numerical model. In addition turbulent trajectories of gas bubbles released from the rotor are predicted. Here the deposition rate of inclusions on the bubble surface is allowed to depend on local conditions. Bubbles passing regions with strong pressure gradients, such as close to the rotor, will experience large slip velocities and large deposition rates. This model can deal with any distribution of bubble sizes and inclusions. The results found from the multidimensional flow predictions are discussed in relation to what can be obtained from a much simpler metallurgical engineering approach. The differences between these two approaches to predict the same process will be discussed. The model predictions are compared to experimental results for removal of SiC-particles from aluminium.

Jan 1, 1996

By Patrick R. Taylor

Iron phosphate glasses are promising host matrices for vitrifying actinide rich nuclear wastes materials because of their high solubility of actinide oxides, high chemical durability, and relatively low melting temperatures. An iron phosphate waste form was developed at the University of Missouri-Rolla. The structure and property of the waste form were well characterized by materials techniques. However, to scale the process and advance it to commercial viability, it is necessary to understand the processing parameters, such as the partitioning of waste elements and the viscosity as a function of temperature. Viscosity of 40 Fe203 - 60 P205 mole % iron phosphate melts (prepared with phosphorous pentoxide and ferric oxide) at 1000-1200 C was measured by the rotating-spindle method. It was discovered that this fluid has non-Newtonian behavior. Experiments were performed to study flow properties following the Standard Test methods for Rheological Properties of Non-Newtonian Materials by Rotational (Brookfield) Viscometer (ASTM D 2196-86). Samples prepared using ammonium phosphate and ferric oxide showed Newtonian behavior and the temperature dependence of the viscosity was studied over the range of 1000 to 1200 degrees C. The difference in flow behavior between the two fluids was analyzed in terms of preparation conditions and variation in the final composition and phases. The partitioning behavior of waste elements in the iron phosphate glass was studied by melting in a high temperature furnace and JCP analysis. The experimental results show that the solubility of Ce and Sr in phosphate glasses is significantly higher than the solubility associated with borosilicate glasses. This strengthens the conclusion that iron phosphate may be a viable alternative to borosilicate glass for immobilization of high heavy-metal-content wastes and actinide rich wastes.

Jan 1, 2002

By D. A. Milligan

Ammonia leaching of copper sulfide concentrates, matte, scrap or other sources of copper yields copper amnine sulfate solutions which are converted to metal in a two-stage process involving precipitation of inter- mediate sulfites and their thermal decomposition to copper powder of high purity. Processing details and results are given. Considerable simplification in circuitry and cost savings are indicated. Energy requirements are reduced by substitution of copper powder precipitation and ammonium sulfate crystallization for solvent extraction, electrowinning and lime boil.

Jan 1, 1976

By Michael Sheedy

Sulfuric acid is widely used as an electrolyte for the electrorefming and electrowinning or metals. Impurities in this electrolyte are controlled by continuously bleeding solution from the tank house. In addition to the contaminant these bleed streams contain high levels of sulfuric acid and the metal being recovered. Subsequent treatment of these bleed streams often requires neutralization which generates large volumes of solid waste. Absorption resin technology employing a novel ion exchange technique known as Recoflo® allows the separation of the mineral acid from dissolved metal salts. The recovered acid is suitable for recycle back to the electrolyte circuit. The metal salt and other contaminants leave the process free .of the sulfuric acid. In this process, known commercially as the APU®, ion exchange resin is used to sorb sulfuric acid while excluding the metal salts. The purified acid is then removed by washing the resin with water. The process has been extensively used for the recovery of waste pickling acids in the steel industry and anodizing solutions in the aluminum industry. In the mining and metallurgical industries the process has been successfully evaluated for the separation of excess sulfuric acid from copper electrolytes, the removal of magnesium and manganese contaminants from zinc electrolytes, and nickel and copper from copper electrolytes. A full scale installation on a copper refinery bleed stream at Palconbridge's Kidd Creek plant in Timmins, Ontario has now been operating successfully for more than 1 year while pilot field trials have been successfully completed on other applications.

Jan 1, 1997

By Varadarajan Seshadri

The performance of mould fluxes in satisfying its quality requirements can have a significant effect on the efficiency of the continuous casting process and on the surface quality of the products. This performance is affected by various parameters including the characteristics of the mould fluxes, the quality of the steel being cast and the operational conditions of the caster. The extremely complex relationships involving the parameters mentioned above make it very difficult to have simple criteria for selecting mould fluxes for casting a certain grade of steel in a continuous casting machine. These difficulties led steelmakers and mould flux suppliers to select mould fluxes based mainly on plant trials. In the present work, a software to help in the analysis and development of mould fluxes for continuous casting was developed. This software includes several models for prediction of mould flux viscosity and consumption. A mathematical model was also used to predict the heat flux through the mould flux. The proposed methodology was applied to continuous casting of crack sensitive steels. Some of the results given by this software are presented, discussed and compared to plant data.

Jan 1, 2003

By Miguel Barron

Recently, a new lance design for BOF steelmaking has been proposed in the literature. This lance, in addition to six peripheral inclined supersonic nozzles, contains a vertical centered nozzle whose oxygen flow is independent from the main oxygen supply. The above authors affirm that their lance maximizes the droplet generation without causing spitting. In this work, the performance of a lance with four peripheral nozzles and one vertical centered nozzle is numerically modeled by means of Computational Fluid Dynamics software. Transient two dimensional computer simulations were carried out considering two phases, namely molten steel and gaseous oxygen. Numerical results confirm that bath agitation and droplet generation are enhanced as a result of the vertical centered nozzle, however a proper performance of this lance, related to a conventional one, strongly depends on the Mach number of the oxygen jets and the lance height.

Jan 1, 2008

By Bo Zhou

During secondary aluminum recovery, complex aluminum scraps are melted and refined often in a rotary melting furnace and the aluminum metal has to pass through a molten salt layer and melt down in a bottom aluminum bath. Previous experimental study and industrial observations have indicated that salt shell formation and re-melting on the metal solids in the early stage plays a critical role in the overall melting process of the scrap. In the present paper, mathematical models are developed to simulate the process of salt shell formation and its re melting, as well as aluminum melting in the molten melt. Influence of the salt layer properties, the residence time of the metal particles in the salt layer, the particle size, the temperature of bulk melt were investigated. Reasonable agreement with the measurement data was reached. The developed melting model will be used to construct a population balance model of the scrap melting behavior for a rotary melting furnace, taking into account the distributed characteristics of the scrap. Finally, an overall process model based on Computational Fluid Dynamics (CFD) for the rotary furnace will be constructed, coupling with the population balance model for the scrap melting.

Jan 1, 2003

By Joel F. Flurnerfelt

Molten Al and Al alloys containing si, Mn, Ti, and y have been lanced with nitrogen-bearing gases. These lancing experiments provided the means for observing what phases form during exposure to nitrogen-bearing gases for finite periods of time, <2 minutes, at high temperatures, >1290oC. The experiments were conducted in sn induction heated drop tube furnace apparatus. The overall premise of these experiments was to select those Al alloys and gas compositions that show promise of forming secondary dispersoid phases, particularly AIN, in the Al matrix. The alloys selected will be atomized using gas atomization reaction synthesis (GARS) using the most favorable conditions. In this case, the chosen Al alloy will be atomized with a nitrogen-bearing gas, such that the Al and gaseous nitrogen species react to form a dispersoid phase within each powder particle. The powder particles that result from this "aggressive" GARS-process would be essentially Al metal-matrix composites within a uniform distribution of dispersoids. To date, only high-purity Al has been atomized using a mild GARS reaction. This work is funded by the Materials Science Division of DOE-BES under contract number W-7405-Eng-82.

Jan 1, 1996

By Don Eby

The application of electric arc furnace smelting of lead, antimony, and tin bearing slag from a reverberatory furnace will be discussed. The selection procedure for the 4.0 MVA electric arc furnace in Indianapolis, Indiana is presented. The design criteria for the transformer, electrodes, refractories and associated equipment is presented. The operation of the furnace including chaJ:9ing, bullion tapping, slag tapping, ventilation, slag composition, metal recoveries, and toxic leach results of thra.1 away slag are discussed. Flow charts and the equipment specifications are given.

Jan 1, 1990

By Liangju He, Peixuan Ouyang, Peijie Li

Single-pulse laser ablation of aluminum and titanium alloys under glass confinement is investigated. Processing parameters such as laser intensity and gap width between targets and glass are varied. Surface morphologies and crater profiles of the alloys after laser ablation are studied by SEM and white-light interferometric microscope, respectively. The effects of gap width and laser intensity on surface morphologies and crater profiles of targets are systematically analyzed. In addition, the generation of porous surface structures in Ti target is regarded as the result of phase explosion in the molten surface layer of targets and the thermodynamic condition in our experiment for phase explosion is evaluated.

Jan 1, 2016