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

"Direct digital manufacturing offers promise as a technique for fabricating complex hydrogen purification membrane support structures. Free form fabrication methods can produce parts with complex structures, and sintering parameters can be controlled to adjust the density, pore structure, pore pathways and strength in catalytic substrate constructs. Efforts are underway to define the influence of selected process variables on the chemical and mechanical properties.IntroductionThe 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. Because hydrogen readily passes through palladium, a structurally sound palladium-based membrane is capable of separating relatively pure hydrogen from other gases. In order for this technology to succeed, a suitable substrate material must be identified.High purity hydrogen is produced by various means. A common method involves a two-stage process for separating hydrogen from a hydrocarbon gas stream: 1) hydrogen-rich syngas is produced by the catalytic reaction of natural gas or another light hydrocarbon gas with steam, and 2) hydrogen is separated from the other syngas components by pressure swing adsorption (PSA) (US. Energy Information Agency, 2011). In PSA, gases enter a column that is packed with a material that absorbs gases as the chamber is filled and pressurized. As the pressure is slowly relieved, the absorbent material releases hydrogen at a higher pressure than the impurity gases. PSA processes produce 99.99% pure hydrogen at a high recovery rate. These systems typically demand a high capital investment due to the high pressure and multiple stages (columns) needed to attain high hydrogen production rates.Research geared toward reducing hydrogen production cost is focused on the development of improved catalysts and adsorbent materials as well as more effective single-stage separation processes. An interesting method combines hydrogen reduction catalysis and filtration. Nascent hydrogen is separated from other gases as it selectively permeates the filter. Catalyst filters may be made of gold, silver, platinum, palladium or precious metal alloys (Davis, 2009)."

Jan 1, 2012

By Mike Dry

While McCabe-Thiele plots are useful for designing single-component solvent extraction systems, not least because of their simplicity, they are less useful for multi-component solvent extraction. This paper presents a relatively simple method, compared to other approaches, for modelling solvent extraction as chemical equilibrium reactions between the various aqueous and organic species. The essence of this approach is how values for the equilibrium constants can be extracted from standard laboratory data. Synergistic solvent extraction of nickel is used to illustrate the method.

By Xue Wang, Callie Babbitt, Chelsea Bailey, Matt Ganter, Gabrielle Gaustad, Brian Landi

"Current trends, motivated by fossil fuel dependence and unprecedented greenhouse gas (GHG) emissions, show lithium-ion batteries (LIBs) emerging as a competitive energy storage technology due to higher power and energy densities compared to Pb-acid and Ni-metal hydride chemistries. These trends may be of concern, however, as environmental impacts are not well understood for either the LIB itself, or for the nanoparticles consumed or released during the battery's production, use, or end-of-life. This study combines economic modeling, dynamic material flow analysis, and fundamental material characterization methods in order to quantify some of the economic and environmental trade-offs for LIBs at their end-of-life. As expected, results show that as chemistries transition from Li-Co based cathodes to Li based Fe, Mn, and S cathodes, LIB recovery value correlates to the value of the raw materials used. These initial results aim to inform collection policies being proposed currently as well as enable future deployment of novel recycling techniques.IntroductionGlobal fossil fuel dependence and unprecedented GHG emissions have led to increasing attention on energy alternatives, for both electricity production and personal transportation. However, development of renewable energy systems is contingent on concurrent technological development of energy storage systems, primarily batteries used for power grid load-leveling, renewable energy storage, and hybrid and battery electric vehicles. In this sector, lithium-ion batteries (LIBs) are emerging as a competitive technology due to higher power and energy densities compared to lead-acid and nickelmetal hydride chemistries[!]. LIBs represent close to 20% of the total rechargeable battery market and 75% of the portable rechargeable battery market, which is the fastest growing segment of the rechargeable battery market, with a 20% global growth in 2008 [2].This surge in production ofLIBs indicates a looming waste problem; total waste from Li-ion batteries has likely grown substantially from the 500 metric tons estimated in 2003 [3]. Figure IA shows the substantial increase in world-wide lithium production that has occurred in the last several decades with batteries making up the largest share of applications (Figure lB). California and New York state legislators have attempted to proactively address this looming waste by issuing diposal bans on rechargeable batteries in their states[4, 5]. However, quantification of the costs involved in collection, transportation, and processing of these materials has not been examined in depth."

Jan 1, 2012

By A. Erçin Ersundu

In the present work, three different domestic iron ores; Sivas Divrigi B Head high grade hematite lump ore, Malatya-Hekimhan-Hasançelebi medium and low grade magnetite lump ores reduced with Soma-Kisrakdere lignite coal to investigate their suitability for sponge iron production. A laboratory scale box furnace was used to carry out the reduction experiments. In the experimental studies different operation parameters were selected being Cfix/Fetot. ratio, temperature in the range of 1100 - 1250 oC and time, to determine their effects on metallization. Metallization degree up to 90 % was found in the reduction experiments realized by using Sivas Divrigi B Head high grade hematite lump ore, whereas for Malatya-Hekimhan-Hasançelebi medium and low grade magnetite lump ores 60 - 65 % metallization degrees were obtained.

Jan 1, 2008

By Kelly J. Driscoll

Impure zinc (98.5%) was electrorefined to high purity zinc (99.995%) using a fused salt electrolyte of molar composition 1: 1 : 1 :2 ZnCI2:KCl:NaCl:LiCl with a current efficiency of about 90% at 723 K. A recessed channel electrorefining cell was developed which achieved excellent mixing of both the metal and the electrolyte and by ensuring a very small anode to cathode spacing the voltage drop across the cell was 0.16 V and at a current density of 7kA m-2. The physical characteristics of the cell were observed using a low temperature model which showed the formation of droplets and rivulets which provided mixing. The application of this approach to the refining of other non-ferrous metals is discussed.

Jan 1, 1992

By Baohua Li, Yanhui Liu, Shengping Li, Xuewei Lv, Yun Chen

There are almost ten billion tons of vanadium-bearing titanomagnetite in Panzhihua-Xichang area. However, iron ores in Hongge, which has the most abundant reserves in the four mine areas in Panzhihua, have not been utilized sufficiently so far. The reason behind this is the relatively high Cr2O3 in the ores (0.49 %~0.82 %), that due to its high melting temperature will negatively influence the blast furnace reduction and slagging process. Therefore, in the blast furnace process, Cr is hope to be reduced into molten iron, which can reduce slag viscosity problems. Slag iron reduction experiments were conducted to quantify the Cr reduction. Experimental results shows that with the increase of TiO2, the content of Cr in the hot metal is decreased when balanced. And during the initial stage of the reduction reaction, the reaction kinetic model is a first-order reaction.

Jan 1, 2016

By Jian Li

Corrosion resistance of materials is highly dependent on the microstructure of the specific material. Apart from general corrosion rate measurement using techniques like linear polarization and A.C. impedance, microstructural investigations are frequently needed to identify the root cause of corrosion. Advanced techniques, including scanning electron microscopy (SEM) and transmission electron microscopy (TEM), have been well integrated into routine characterization studies. Other microscopy techniques, including electron probe micro-analyzer (EPMA), Auger, X-ray photon spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS), can provide detailed chemistry information on corrosion products. In recent years, focused-ion beam (FIB) microscopes have evolved into an important microstructural characterization instrument. In this study, corrosion of rebar encased in concrete was studied in great detail using advanced microscopy techniques. Corrosion product on the rebar surface was identified as ferrous oxide with relatively large crystal size. The morphology of this passive layer was thoroughly analyzed, and its formation mechanism is proposed.

Jan 1, 2009

By Joseph Sofra

It has become increasingly evident that sustainable metals production in the 21" century requires producers to balance the needs of cost effective, high value production with that of responsible plant operation. This is becoming more difficult as lower grade and more complex feed materials, including recycled scrap and residues, arc being processed to reduce production costs and decrease exposure to primary metal market fluctuations. One particular facet of the metals industry facing these challenges in the 21 st century arc copper producers. The recent steady decline in the copper price has seen the industry cut expenditure, tighten control on income streams and focus on high returns on capital investment. For these reasons copper producers arc looking towards flexible technologies that can deliver high value products, with minimal environmental impact at low capital and low sustainable operating costs. Ausmelt's Top Submerged Lancing (TSL) technology for copper production is a low cost, proven technology for the processing of both primary and secondary copper materials. Both the smelting and converting operations introduce significant advantages in environmental performance, improved process efficiencies and high rates of metal recovery. Ausmelt has made significant gains in the past 4 years in establishing a strong market position for its copper technology. New installations in China, South Africa and India as well as existing operations in Zimbabwe and China have demonstrated its effectiveness. This paper reviews the application of Ausmelt Technology for both smelting and converting of primary and secondary sources. It discusses Ausmelt's design and implementation philosophy, and how this philosophy meshes with the needs of the end user.

Jan 1, 2003

By Michael A. Krstich

A soil washing pilot plant to treat soils at the U.S. Department of Energy (DOE) owned Fernald Environmental Management Project (FEMP), was designed based on extensive bench-scale testing. The system's design incorporated a combination of physical separation and' chemical extraction processes and was tested on two soils. The textural composition of the two soils was approximately 20 percent sand, 60 percent silt, and 20 percent clay. Since this grain size distribution was not considered optimum for physical separation techniques, thesoil washing pilot plant had to be designed with selected equipment to provide specific soil size fractions during processing operations. A trommel, vibrating screen deck, centrifuge, and attrition scrubber were used in the system to selectively separate specific soil size fractions at 4.75, 2, 0.3, and 0.02 millimeters (mm). The trammel used high pressure water [1000 pounds per square inch (psi)] during the initial step of the process to reduce soil aggregates to single grain composition, separate out greater than 4.75 mm gravel, and dislodge chemical contaminants from the individual soil particles. The vibrating double-screen deck provided 2 - 4.75 and 0.3 - 2 mm soil fractions that, when combined, averaged greater than 75 percent solids for both soils. The centrifuge was designed to take the less than 0.3 mm soil slurry from the screen deck and produce a particle size of 0.02 mm. The centrifuge produced a high solids stream that averaged greater than 70 percent solids for both soils. These 0.02 to 0.3 mm soil solids from the centrifuge were combined with the 0.3 to 4.75 mm soil solids from the screen deck and processed through the attrition scrubber. The data collected from the pilot-plant operation was used to aid in the design of a full-scale system and was instrumental in formulating full-scale process operations and the selection of equipment.

Jan 1, 1995

By Akita Ito, Sumio Kato, Mikio Sugai, Shinichi Nakata

"Spark Plasma Sintering (SPS) is a newly developed method for the sintering of metal and ceramic powders, and completes their densification at low temperature and in short period. The SiC powder was synthesized from diatomite and graphite or carbon black by heating at 1 450°C for 1 hr in an argon atmosphere. The synthesized SiC powder was heated at 1500-1800°C, 50 MPa for 15-18 min by SPS. The relative density of sintered SiC body increased with the rise in the temperature. The oxidation of the surface of the SiC particle and impurities in SiC from diatomite greatly influenced the sintering promotion of SPS.IntroductionThe SiC has high hardness because of the covalent bonding, and is also excellent in thermal and chemical stability. However, it is difficult to obtain a dense SiC sintered body by the combustion heating-method. Therefore, the dense SiC bodies have been made by the use of additives and I or the hot pressing (HP) method.In this study, the SiC powder was synthesized by using diatomite of natural products and graphite, and carbon black of reagent as raw materials, and the relationship between the properties of SiC powders prepared at various synthetic conditions and the density of sintered body by SPS was examined."

Jan 1, 2000

By Yang Guangqing, Shao Jiugang, Zhang Jianliang, Wan Dan, Fu Yuandi, Guo Hongwei

"Resource of metallurgical coke is becoming scarce, and although coke can be partially replaced by pulverized coal injection, there are many restrictions for further increase in coal ratio. Mixed charge of ore and lump coal from top to replace more coke was studied in this paper. Softening-melting property of the burden was affected by charge of lump coal. Softening-melting properties of mixed charge of ore and coke, mixed charge of ore and lump coal were tested respectively. Results show: the property of the burden mixed with coke is superior to the burden mixed with lump coal; lump coal would not deteriorate softening-melting property of the burden and some of them can even improve softening-melting property of the burden. Top charge of lump coal would not deteriorate softening-melting process, and this should be a new way to increase coal consumption to decrease coke rate.IntroductionThe blast furnace is still the predominant process for the reduction of iron ore and will probably remain so for the next decades. Metallurgical coke is becoming scarce and expensive, so the cost of hot metal can be decreased by reducing the consumption of metallurgical coke[l]. Coke can be partially replaced by pulverized coal injection, currently the highest rate of pulverized coal reached 266kg/tHM, most of blast furnace PCR is about 150kg/tHM, and it is very difficult to further increase of PCR. Nut coke is charged into blast furnace mixed with iron ore, not only for improving utilization of metallurgical coke, but also for lowering the coke rate. Presently the majority of blast furnaces in the world use nut coke although its amount is very different: from 10-20 to 70--100 kg/tHM and more[2-4].The effect ofnut coke in blast furnace is extensively researched, and the main conclusions recommend: to improve gas permeability of cohesive layer in blast furnace, to promote reduction of iron burden, protect metallurgical coke from the solution in the shaft due to higher reactivity of nut coke. There is no special requirement for the strength of nut coke[5-8]. Nut coke is also used for sintering fuel, which may lead to the shortage of the nut coke charging into blast furnace. So lump coal mixed with iron ore is considered to be charged into the blast furnace, not only to reduce the cost of grinding coal, but also to increase the use amount of coal."

Jan 1, 2013

By Wang Shuchan, Zhang Zimu, Zhang Dianhua, Liu Yan, Zhang Ting-an, Zhao Qiuyue, Lv Chao

Rare earth extraction tank has many adverse effects like big floor space and high production accumulation during industrial production. Current researches usually focus on changing the device structure without making a breakthrough towards gravity clarification. This paper attempts to achieve this goal by using both the action of clarification by gravity and clarification by stirring. Because many physical parameters affect the clarification and separation rates, the density, viscosity and surface tension of the two phases were determined at different temperatures and different concentration of aqueous solution. The innovation of this research involves adopting the Karl-Fischer method to investigate water content in oil phase during the stirred separation process. In this paper, the separation effect of different physical parameters was studied and the dimensional equation between water content and the physical parameters was established by combining with the experimental data.

Jan 1, 2014

By Bob Hannah, Peter C. Hayes

The changes that are happening in the world of metallurgy, and with it university education, are generational and require generational responses. Some of the key issues facing metallurgical education and ongoing professional training are explored. What will be required of metallurgical engineering professionals in the coming decades? What knowledge and skills will be needed? How to provide the educational and learning pathways, and how to attract smart young people into this profession? These are issues more readily addressed by tertiary institutions in conjunction with industry; perhaps the greater challenges lie in building and maintaining competencies post-graduation. There is a need to establish and maintain a system that supports graduates and enables them to develop further into competent expert engineers able to successfully address complex engineering challenges.

Jan 1, 2014

By Dave Tahija

"Many investigations are being performed with the goal of removing carbon dioxide from the atmosphere and permanently storing it in geologically stable settings. At the same time, carbon dioxide in the form of dissolved carbonate is steadily accumulating in the world's oceans. Both carbon dioxide sequestration and oceanic accumulation are constrained by the aqueous thermodynamics of the carbonate system. These constraints are illustrated using the STABCAL computer model to generate potential-pH and aqueous distribution diagrams of seawater in contact with various pressures of carbon dioxide gas. STABCAL diagrams and titration simulations are also used to model some potentially useful cation-carbonate sequestrationsystems.IntroductionAtmospheric carbon dioxide concentrations have risen dramatically in the past couple of centuries and are rising still, primarily as a result of human activities, especially the burning of fossil fuels. Increased atmospheric carbon dioxide concentrations have been implicated as a main cause of global warming but have other effects as well.Rising levels of atmospheric carbon dioxide result in increased concentrations of dissolved carbonate complexes in water, including the oceans. These dissolved carbonates interact with other dissolved substances, altering overall seawater chemistry, most noticeably causing lowered pH levels.Some of these chemical changes are observed directly, for instance the general drop in oceanic pH, [1], while others can be inferred and predicted using thermodynamic modeling. The chemistry of dissolved carbonate in seawater is not especially intricate, as such chemical systems go, but neither is it simple enough to be worked out on the back of an envelope. Interactions between the several simple carbonate species and all the major dissolved cations in seawater should be considered, as well as the effects of competing anions, especially chloride and sulphate, since they are much more abundant than carbonate in seawater."

Jan 1, 2011

By Junwei Han, Wenqing Qin, Dawei Wang, Fen Jiao, Wei Liu

The removal of iron impurity from zinc calcine was studied by magnetization roasting and magnetic separation. The effects of roasting temperature, magnetic intensity, ore grinding, and leaching pretreatment on iron grade and recovery were investigated. The results indicated that iron recovery increased with the increase of roasting temperature or magnetic intensity, while iron grade was always less than 22%, depending on the fact that the magnetite were not liberated completely. The good liberation was difficult to be achieved by ore grinding but was easier by acid leaching, since the magnetite grains were very fine. After the leaching pretreatment, the recovery of 76.31% with iron grade of 53.24% was obtained by one roughing and cleaning. The SEM/EDS analysis showed that a part of sphalerite, zinc ferrite and other gangues were mixed into the iron concentrate, while some of fine magnetite was reported to the tailing.

Jan 1, 2016

By Rodney T. Jones

DC arc furnaces were first used industrially for the reductive smelting of chromite fines to produce ferrochromium thirty years ago. Since then, they have been used for a variety of applications, including the smelting of ilmenite to produce titania slag and pig iron, the recovery of cobalt from non-ferrous smelter slags, and the smelting of nickel laterite ores to produce ferronickel. The power of these furnaces has increased from 12 MW to 72 MW for ferrochromium, and to 80 MW for ferronickel. The largest of these furnaces requires two electrodes to carry sufficient current to generate this much power. A review is presented of various DC arc furnaces in use, along with a discussion of the likely ways in which furnace power might be increased further in the future.

Jan 1, 2014

By Edward Peters

Scandium (Sc) has unique properties and is one of the more valuable elements in the periodic table. Scandium can be used in solid oxide fuel cells and to produce high strength aluminium alloys of value, for example, in the aerospace industry. Scandium is often grouped together with the rare earth elements (REE). Amongst others, scandium can be found in bauxite residues, so called red mud. It is possible to extract and enrich scandium from red mud by leaching and solvent extraction. Scandium can then be recovered from the pregnant strip liquor by crystallization. The strip liquor will however still contain certain impurity elements. In the present work, a method for obtaining a pure scandium solid phase by direct crystallization from the strip liquor is evaluated. It was found that Fe and Ti co-precipitate with Sc under the conditions employed.

By Jiling Wang, Xuefeng Liu, Haojian Duan, Lifeng Zhang, Ying Ren, Wen Yang

"In order to study the influence of MgO-C refractory on steel cleanliness and inclusions during steelmaking process, and to understand the reaction mechanism deeply, laboratory deoxidation and equilibrium experiments were respectively performed in MgO crucibles at 1873K. In the former experiment, after Al addition, steel samples were taken at different holding time. In the latter experiment, different slag components and different contents of carbon and aluminum in steel were considered respectively. The inclusion characteristics of each experiment were analyzed. The results showed that with the increasing of holding time after deoxidation by Al, MgO existed in the small inclusions firstly, and then in the large ones such as the clusters. The MgO content in the inclusions increased with the increasing of holding time, indicating that the MgO in crucible could be individually reduced by the aluminum in the molten steel. The reaction could occur within nine minutes.IntroductionNon-metallic inclusions would have positive or negative effect on steel quality depend on the quantity, size and composition of inclusions. Large inclusions are always detrimental. From the point of view of inclusion property, plastic inclusions are required by steel cord, while hard inclusions are preferred by pipeline steel. One of the most important ways to increase the steel quality is reducing the inclusion size and controlling the inclusion composition in steel. Nowadays, MgO based refractory is used as ladle glaze material with more and more frequency, which results in different inclusion characteristics in molten steel, for example, the inevitable generation of MgO contained inclusions during ladle treatment of steel. In other words, the inclusions in this type ladle will influence on the steel cleanliness and the product property. Thus, keeping an eye on the inclusion formation behavior in the steel with MgO-C ladle glaze is important for the steel industry. There have been a few studies in this regard. Li et al[l] studied the reactions between MgO-C refractory, molten slag and metal using a high temperature X-ray radiographic apparatus. They found that the local corrosion was regarded as due to the cyclic dissolution of MgO and graphite in the refractory into slag and metal phase. The gas bubbles formed according to the reaction of (FeO)+C(s)=Fe(l)+CO(g) greatly influenced the corrosion. On an industrial scale, Du[2] found that ladle glaze is a major source of inclusions in the ladle. An experimental study has been performed by Lehmann in order to estimate the importance of the reaction between a MgO-based tundish refractory and an Al-killed steel[3]."

Jan 1, 2014

By Jan Smit

Sulphidic copper concentrates are generally processed by pyrometallurgical means; while oxidative pressure leach processing of such materials has been shown to be technically feasible, there has traditionally been little incentive to choose this route in favour of a smelting option. However, for concentrates with elevated arsenic levels, oxidative pressure leaching offers distinct advantages, as smelter air emission standards and restrictions on concentrate importation have tightened. The current state of pressure leach technology allows for high copper extractions from arsenical copper concentrates, while producing an environmentally stable process residue, without atmospheric emissions of sulphur dioxide or arsenic. In its studies on pressure leaching of copper concentrates, Sherritt has shown that arsenical feed materials can be converted into environmentally stable residues, with excellent copper extractions. The results of recent batch and pilot plant test work are discussed, including the deportments of copper, arsenic and precious metals.

By Edgar E. Vidal, Keith Smith, James A. Yurko

Beryllium, like many other reactive metals, is extracted from a halide (generally BeF2) using magnesiothermic reduction, also known as the Kroll process. The beryllium is produced in a molten state, which when solidified resemble "pebbles". Although beryllium is used in limited quantities compared to other metals (< 100 Mt/annual), it is a critical material for the nuclear, defense/aerospace, and large science markets because of its unique nuclear and mechanical properties. Beryllium processing has unique environmental, health, and safety concerns which must be handled appropriately in the 21st century from a worker and environmental safety perspective, and must be designed with this first in mind. In 2011, Materion began operations of its new Kroll plant – informally known as the “Pebbles Plant” - in Elmore, Ohio. The plant was majority funded by a U.S. Department of Defense Production Act (DPA) Title III grant, which is a unique government/industry partnership program to, "create assured, affordable, and commercially viable production capabilities and capacities for items essential for national defense." After a twelve year hiatus from primary beryllium production, Materion has reentered its extraction business and has relearned how to make pebbles. The purpose of this presentation is to give an overview on beryllium extraction and discuss some of the unique aspects of building and operating a safe beryllium facility during the production scale-up phase.

Jan 1, 2015