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By C. J. Newman

The new Kennecott Utah Copper smelter, started in 1995, was designed to be the cleanest smelter environmentally in the world. The plant is operating at production rates above the original design capacity. Copper concentrate is smelted in an Outokumpu flash smelting furnace. Matte is granulated and processed using Kennecott-Outokumpu flash converting. Copper anodes are processed in a modernized copper refinery using the Kidd Process while anode slimes are processed for precious metals recovery using a unique hydro-metallurgical process. To allow the production of high quality cathode, using modem smelting and converting technology to minimize emissions, impurity control had to be carefully addressed. All process bleed streams from the smelter and refinery are treated in a hydro-metallurgical plant to fix impurities in a stable form, allow for the rejection of impurities as required and recover valuable metals. Special technology was developed for the copper refinery to ensure production of high quality cathode from anodes containing high levels of impurities. The smelter routinely achieves a sulfur capture in excess of 99.9% which is equal to less than 2 kg of SO2 per tonne of copper produced. This paper describes the design of the smelter and refinery and includes recent production and emission data and modifications carried out to allow operation at above the original design rates. It emphasizes the unique features required to achieve environmental and quality goals and compares environmental performance data to that published on other smelting operations. The processing of intermediate streams, the management of recycled materials and the impurity control strategy will be covered in detail.

Jan 1, 1999

By Katsuyoshi Tatenuma

"In order to mitigate the effect of global warming by preventing the accumulation of atmospheric CO2, a permanent fixation method of surplus CO2 as an insoluble mineral onto the sea bottom is proposed. As the proposed reduction method of atmospheric CO2, the concrete concept of this method is to form an insoluble carbonate mineral (CaCO3) by direct electrolysis of the seawater; Ca2++2HCO3 -+OH- ? ?CaCO3(insoluble)+CO3 2- (soluble)+H++H2O <not as coral reef reaction>, are directly disposed of itself onto the sea bottom. By this treatment, a concentration of carbonate is reduced in the section of superficial seawater, and therefore the absorption capacity of atmospheric CO2 increases depending upon the shift of chemical carbon equilibrium between the mass of superficial seawater and the atmosphere. As no additives are required, or no secondary waste are produced, the proposed method assuming as green-orientated, has possibility to resolve fundamentally the problem of global warming in a green orientate manner.IntroductionRecently, the amount of atmospheric CO2 has been exponentially increasing and it is a main greenhouse effect gas causing the global warming [1, 2]. The concentration of atmospheric CO2 has increased more than 30% (370ppm in 2001) during only last two centuries, therefore approximately 750 Gton-C of CO2 currently exist in the atmosphere, in which 180 Gton-C of CO2 are accounted for the increment during two centuries [1, 3, 4]. In order to avoid the progressive increase of CO2 global abundance, 3 Gton-C of the incrementing amount per year [4], have to be removed annually from the atmosphere."

Jan 1, 2008

By D. M. Jones

Dust generation data have been obtained from 19 industrial Outokumpu flash furnaces. Statistical analyses of the data have been carried out and the most significant factors affecting dust generation evaluated. The results indicate that dust production may most effectively be minimized by: 1) Minimizing the distance between the molten slag and the furnace roof 2) Optimizing burner design and combustion parameters.

Jan 1, 1996

By Michael A. Markowitz, Alok Singh

"Molecular self-assembly of phospholipids and other amphipathic molecules offers a versatile approach to form self-organized microstructures in various morphologies. Stabilization of microstructures in specific morphologies by polymerization renders them useful for practical applications in areas ranging from controlled release technology to template mediated synthesis of metals. Our efforts are focussed on the development of polymerizable biomembranes derived from phospholipids, their properties and utility e.g., as stable templates for studying chemistry at the lipid interface. Polymerized vesicles formed from mixtures of 1,2-bis(tricosa-1 O,12-diynoyl)-sn-glycero-3-phosphocholine, 1, with corresponding lipids having phosphohydroxyethanol,2, or -hydroxypropanol,3, headgroups have been used in electroless metal plating of vesicle surface with gold utilizing selective binding of Pd(NH3)4 2 + to 2 or 3. The surface bound palladium ion served as catalyst for metalization. Metalization of polymerized vesicles constructed from charge neutral diacetylenic phosphocholine,1, did not occur using this process. The headgroup structure of the negatively charged phospholipids and the degree of vesicle polymerization had an effect on the stability of the vesicles after metalization. Vesicles formed from a mixture of 1 with polymerizable diacetylenic phosphatidic acid, nonpolymerizable 1,2- dipalmitoyl phosphohydroxyethanol or 1,2-diacyl phosphohydroxyethanol (from soy lecithin) were not stable to metalization process. The metal coating of the vesicles was examined by electron diffraction and revealed that the gold metal on vesicles was polycrystalline and face centered cubic. The results demonstrate the utility of polymerized synthetic membranes as template for easy and efficient synthesis of nanoparticles. IntroductionPhospholipids, synthetic or natural, provide a simple and straight forward route to construct membranes in a variety of morphologies due to their inherent property of selforganization in the presence of water[1]. Vesicles are closed spherical structures comprised of concentric walls made from lipid bilayers. Vesicles are morphologically simple structures with enormous technological potential. Polymerizable phospholipids prepared by incorporating a polymerizable group in the molecules demonstrate physical properties comparable to their non-polymerizable counterparts and have the added virtue of providing enhanced physical and chemical stability to the membranes[2,3]. The size, shape and properties of the organized assemblies are dependent on the lipid structure and the nature of the aqueous environment[4,5]. The headgroup geometry, surface charge density, and spatial arrangement of the phospholipids are known to affect the surface behavior of the lipid membranes, which is evident through their interaction with other molecular (hormones, antigens, antibodies etc) or lomc species. Since phospholipid headgroup structure and charge can be modified either synthetically or by chemical perturbation of the aqueous medium (e.g., pH or ionic strength), phospholipid membrane surfaces offer a potential for developing novel strategies in those areas which involve the use of molecular reactive sites. One such strategy which could be envisioned explores the use of molecularly engineered phospholipid assemblies to design and prepare template structures to regulate formation of ordered materials [6]."

Jan 1, 1994

By D. E. Larson

The U. S. Bureau of Mines has developed a image analysis methodology to correlate the energy consumed during the grinding of an ore to the mineral liberation achieved. Energy consumption values are obtained using a laboratory-scale ball mill equipped with a torque sensor, and an automated image analyzer is used to determine the liberation present in ground products. By combining liberation information with energy consumption data an appraisal can be made of the energy required to liberate the mineral(s) of interest. Results of tests performed on a complex sulfide material determined the effects of grind duration on the liberation achieved and the energy efficiency.

Jan 1, 1995

By G. R. Adams, N. Y. Tang, N. Qiang

"Aluminum is the most important alloy addition to Zn baths for controlling the reaction kinetics between the steel substrate and molten Zn in continuous galvanizing operations. Due to the complexity of the Zn-Fe-Al ternary system, the measurement and control of effective bath Al remains a challenge for modem galvanizers. The successful development of Al sensors has made the real-time measurements of bath Al contents possible. To facilitate their application, a computer interface and a palm-size data logger have been developed by Cominco. Plant applications indicated that the sensor possessed sufficient accuracy for process monitoring and control. The working mechanism of the Al sensors and Cominco's development work is described, and the results of sensor applications are presented.IntroductionControl of bath Al content is critical in modem continuous galvanizing because it has a strong influence on coating structure and properties and the overall product quality. The control of effective bath Al content (Al in liquid solution) is particularly critical for galvannealing where a high bath Al content may lead to incomplete alloying during post annealing, and a low bath Al content may result in other operation problems, such as excessive bottom dross accumulation and difficulties in coating thickness control. The desirable accuracy of the Al control is within ±50 ppm of target levels. In principle, such an accuracy is achievable for modem chemical analysis facilities, such as atomic absorption photospectrometer (AAS) and induction-coupled plasma (ICP). However, a recent study carried out by the International Lead and Zinc Research Organization (ILZRO) indicated that such an accuracy is rarely achieved in the zinc and steel industries.(1)"

Jan 1, 1997

By C. A. Nogueira, F. Margarido

"A research work has being carried out annmg at evaluating the possibility of treating simultaneously several electrochemical systems of spent batteries using the same process, in order to overcome the high costs and difficulties of selective collection and sorting. Zn-Mn02 systems, representing more than 75% of portable battery market, shall be treated in dedicated processes. The treatment assessment using a single hydrometallurgical process of the other major systems (NiCd, NiMH and Li-ion), having Ni and Co as main metals, was the aim of the research work here reported. Sulfuric acid leaching was demonstrated to be adequate for dissolving more than 90% of the metals of interest contained in batteries. The subsequent separation of metals by solvent extraction, using organophosphorous extractants like DEHPA and Cyanex 272, allowed the production of pure solutions of rare earths, cadmium/manganese, cobalt, nickel and lithium, enabling their further recovering.IntroductionRecycling is the best approach for end-of-life management of spent batteries mainly by environmental reasons but also motivated by resources conservation and, in some cases, by economic profits. Most relevant electrochemical systems of portable cells are Zn-Mn02 (ZMB, alkaline and saline), nickel-cadmium (NiCd), nickel-metal hydride (NiMH) and lithium-ion (LIB). These batteries are collected, sorted and usually treated separately, applying for pyrometallurgical or hydrometallurgical technologies, the former being the most common.Several processes have been developed and some of them industrially applied, as described in some available review papers [l, 2]. In Europe for ZMB systems the oldest processes are Batrec [3] and Citron [4]. Although having differences in details, both are based on pyrometallurgical recovery of zinc by distillation, in metallic or oxide forms, being manganese retained in the slag together with iron. Hydrometallurgical alternatives are also available, like Zincex [5] and Recupyl [ 6] processes, both using sulfuric acid solutions as leachant. The application of the existing technologies to battery recycling, instead of using dedicated processes, is other alternative already tested, being the Waeltz furnace or the Imperial Smelting some examples."

Jan 1, 2012

By Liu bing-guo, Peng Jin-hui, Guo Sheng-hui, Kong dong-cheng, Hu jin-ming, Zhang Li-bo

The novel technology of calcination to prepare triuranium octaoxide（U3O8）from ammonium uranyl carbonate in microwave fields was investigated on the basis of the temperature rising characteristics of ammonium uranyl carbonate, triuranium octaoxide (U3O8), and their mixture. The result of experiments show that ammonium uranyl carbonate had weak capability to absorb microwave energy, while triuranium octaoxide has the very strong capability to absorb microwave energy and the sample temperature increased rapidly with an increase mixture ratio of triuranium octaoxide. The optimal calcination conditions were as follows: microwave power 700 W, calcination time 10 min and 60 g in this experiments range, respectively. Under these conditions the value of total uranium and 4 U of triuranium octaoxide was 84.28% and 31.02%, respectively. It is feasible to prepare triuranium octaoxide by calcination from ammonium uranyl carbonate, which mixed with small amounts of triuranium octaoxide under microwave fields.

Jan 1, 2015

By Yong J. Kim, J. M. Park

"Solid/melt interface shape during continuous casting process has a strong influence on the resulting microstructure of the ingot. The interface shape is primarily governed by the heat flow condition between the molten metal and mold (or container). The roll of the microstructural transition resulting from various solid/melt interface shapes is discussed using the Sn-22.6wt%Pb alloy. Three different types of mold such as cold mold, resistantly heated mold, and electromagnetically heated mold were used to generate those interfaces having different curvatures. Experimental measurements of complete temperature profile along the axis and surface of the ingot during downward continuous casting are presented to determine the solid/melt interface geometry. The results provide an explanation of the ingot property with emphasis on microstructure.IntroductionA large scale of continuous casting process of alloys often has a rather deep V channel type of solid/melt interface resulting from a limited heat flow condition. As a result, the deep V type solid/melt interface shape entraps defects such as pores and inclusions and also creates canter segregation. In order to reduce the defects concentration, electromagnetic stirring(EMS) mechanism has been applied to the melt in the channel[l]. Speith and Bungeroth introduced first experimental EMS device to the continuous caster in 1952.[2] Today, with wide ranges of benefit, a large variety of such technique is available. Electromagnetic field on the melt can be divided into three aspects. First, eddy current is induced on the metal surface by alternating magnetic field with high frequency, which results in heating the metal. Second, electromagnetic body force which is generated by the magnetic field and the eddy current reduces the melt pressure on mold or support the melt not to contact with the mold[3,4,5]. This force is used for electromagnetic casting process(EMC). Finally, it causes stirring in the melt. Many research efforts have been done on the EMC process to improve surface quality of slab[6] and control meniscus shape where three phases such as melt, solidified metal, and mold powder coexist[7,8]. However, the eddy current heating effect on the surface of the ingot was less considered. It is worth noting that induced eddy current on the surface of slab melts the solidified shell and thus changes the heat flow condition between the mold and melt. Mold heating effect was first proposed by A. Ohno[9] and its processing conditions were identified in details[ 10, 11]. The so-called Ohno process is based on the fact that by keeping the mold temperature slightly above the melting temperature of the liquid, no grain can be nucleated on the mold wall[12]."

Jan 1, 1998

By Raymond M. Coveney

Bedded sulfide ores in Cambrian Chinese black shales typically contains at least 2% Ni, 4.5% Mo, 1% As and 0.2% Se. Thin laminae and replaced on colites from the ore contain intimate mixtures of fine-grained Ni-rich sulfides and jordisite complicating ore treatment. The ores contain abundant jordisite, vaesite, nickelian pyrite, and barite and lesser amounts of sphalerite, gersdorffite, millerite, tennantite, fluorite, chalcopyrite, and HgSe (probably tiemannite). At present only ores that are sufficiently rich (>4.5% Mo) for direct roasting are mined and treated to produce, ammonium molybdate. The ores contain Pt, Pd, and Au in amounts totaling up to -2.5 ppm, but these are not recovered.

Jan 1, 1993

By René Winand

Due to chemical and electrochemical behavior of the most common additives in copper electrorefining i.e. gelatine, thiourea and chloride ions, it is essential to simulate as far as possible true industrial practice while performing laboratory experiments. The three additives must be studied simultaneously, and added continuously to the electrorefining cell. Ratio electrolyte volume to cathode area; ratio bleed flow to cathode area; hydrodynamic conditions; residence time of electrolyte in the cell; current density; electrolyte and soluble anode must be as near as possible to industrial ones. Experiments performed in the author&apos;s laboratory show that under these conditions, reproducible results can be obtained at normal industrial current density and at high current density as well. Problems are however still encountered when developing a sensor for additives monitoring, due to electrolyte redox potential and to substrate influenced thin layer deposition.

Jan 1, 1995

By John ?gren, Martin Schwind, Henrik Larsson

"A new model for internal oxidation, as well as similar processes, has been implemented on computer. It is based upon a combination of random walk and cellular automata and is capable of treating 3-dimensional cases. To model diffusion, it utilises quantised units of matter. All steps of the process are included: nucleation, growth and coarsening. The effect of grain boundaries on diffusion as well as nucleation is taken into account. Further possible development is briefly discussed; especially the treatment of nucleation needs further consideration. IntroductionComplex diffusion-controlled processes may now be simulated on a routine basis when concentration varies along one co-ordinate only. One-dimensional simulations capture much of the information of interest but not all. For the case at hand, especially the spatial and the size distribution of precipitates, as well as the impact of grain boundaries, would be interesting information not accessible from 1-D simulationsSolving the full Fick-Onsager law in three dimensions does not seem feasible with the computers of today. In the model described in this article, random walk by quantised units of matter are considered. The model should be useful for a number of cases involving dispersed systems. With further development, it would indeed seem possible to simulate most types of phase transformations.Previous workWe have previously published two articles [1,2] on the new approach discussed in this work. In those articles we described the basic idea and showed, among other things, that very good agreement with an experimental concentration profile can be obtained, in a single-phase system, using independently assessed thermodynamic and kinetic data. Also, Schwind used the same random walk based concept to model coarsening [3]."

Jan 1, 2001

By K. Potluri, S. Akella, S. Bhansali

"This paper presents the design and angular strength analysis of microneedles for use as a transdermal interface for drug delivery, fluid analysis and sampling etc. Microneedles of different dimensions were designed and fabricated using various materials viz. Si02, OxideNitride- Oxide (O-N-0). The design, modeling and analysis was done using the Finite Element Analysis (FEA) software ANSYS™ 6.1. Angular strength analysis of the microneedles was done using angular loading in ANSYS™, with the corresponding inaterial property settings. Using the force-displacement settings, forces of magnitudes in the range of 10 mN - 25 mN were applied on the microneedles at loading angles ranging from 30° to 90° was applied on needles. Square and circular shaped microneedles were modeled and the displacements and stresses generated were studied to characterize the angular strength of the microneedles. The buckling and force-displacement analyses show that O-N-O microneedles are more strong and robust as compared to needles of other materials. The analysis shows that while circular microneedles have uniform stress distribution, square microneedles have low stresses concentrated along the edges.INTRODUCTIONIn modem clinical and biomedical applications, drug delivery is done either by oral administration or by hypodermic injection. Hypodermic injection of drugs using needles is often painful. Hence, transdermal drug delivery techniques are increasingly being sought out as an alternative. In transdermal drug delivery the needles puncture the Stratum comeurn - the outermost layer of the human skin. The advantage of transdermal drug delivery (or transdermal measurement) technique, is that it reduces pain and tissue trauma."

Jan 1, 2004

By E. Kozeschnik

A new model is presented for the simulation of the evolution of precipitates in a multi-component multi-particle multi-phase environment The mathematical formulation as well as the physical background of the model are briefly introduced and its capabilities are discussed on the example of a precipitation sequence in a complex steel. Keywords: Modeling, precipitation kinetics, nucleation, growth, coarsening

Jan 1, 2003

By B. Balamurugan, D. J. Sellmyer, J. E. Shield, G. C. Hadjipanayis, Damien Le Ror, R. Skomski

"Rare-earth transition-metal (R-TM) alloys show superior permanent magnetic properties in the bulk, but the synthesis and application ofR-TM nanoparticles remains a challenge due to the requirement of high-temperature annealing above about 800 °C for alloy formation and subsequent crystalline ordering. Here we report a single-step method to produce highly ordered R-TM nanoparticles such as YCO5 and SmCO5, without high-temperature thermal annealing by employing a cluster-deposition system, and we investigate their structural and magnetic properties. Nanoparticles of size = 10 nm are monodispersed (s /d ~ 0.15) and have Hc values at T = 300 K of 8.0 and 4.5 kOe for YC05 and SmC05, respectively. Alignment of the easy axes is performed via a field applied to the clusters before deposition. These processing steps are highly desirable to create and assemble R-TM nanoparticle composites for future permanentmagnet applications.IntroductionMagnetic nanoparticles with high magnetocrystalline anisotropies (Ki > 1 MJ/m3) are required for permanent-magnet, recording-media, and other significant applications [1-3]. In this regard, bulk rare-earth transition metal alloys (R-TM) especially RC05 (R = Y and Sm) crystallized in the hexagonal CaCu5-type structure have shown a large Ki = 5 MJ/m3 (YC05) and 22 MJ/m3 (SmCo5) along with an appreciable saturation-magnetic polarization (Js, > 10 kG) and high curie temperatures (Tc > 1000 K) [2]. The challenges in controlling the size, sizedistribution, phase purity and crystalline ordering, however, limit the research on RCo5 nanoparticles [4,5]. The conventional arc-melting technique requires high-temperature annealing for alloy formation and subsequent crystalline ordering, which causes excess growth and thus results in nanocrystalline powders of particles sizes larger than 30 nm [6, 7]. Low-temperature wet-chemical techniques yield SmC05 nanoparticles of sizes smaller than 20 nm [5], but the control of phase purity is challenging due to the presence of surfactants and formation of other secondary phases [8]."

Jan 1, 2012

By Xin Zhang, Xu Zhang, Hao Bai, Ning Li

Organic Rankine Cycle (ORC) is an effective technology for low-grade waste heat power generation. In this paper, the thermal-dynamic performance of ORC system, in which low-temperature waste heat (from 40-140oC) is used as heat source, was evaluated with software RefProp8.0. The result indicates that in the range of low temperature, the working fluids like R601, R601a, R600a, R141b, R245fa and R245ca have better thermal performance. Furthermore, pilot-scale experiment using R245fa as working fluid was conducted, which validated the operation of the system for low-grade waste heat recovery. Finally, the economic feasibility of ORC has been analyzed for an ORC system using the waste heat from quenching water of blast furnace slag (80oC). According to the analysis, the project is reasonable in economy because the recovery period of investment is less than 4.2 years and environment-friendly since the CO2 emissions can be reduced by almost 43650.68t annually.

Jan 1, 2016

By Yousef Mohassab, Manoranjan Misra, Monalisa Panda, Eman Wahbah

This work studies the removal of arsenic (V), arsenate, and arsenic (III), arsenite, from aqueous solution using calcined Quintinite-3T. The two adsorbents Quintinite-3T was prepared, calcined at different temperatures, and characterized by XRD, BET, and SEM. The surface area of the calcined Quintinite-3T was 193.4 m2/g. The particles size ranged from 12 to 56 nm for the uncalcined Quintinite-3T and from 24 to 42 nm for the calcined Quintinite-3T. Kinetic analysis, adsorption isotherm, and factors affecting the adsorption were investigated. Calcined Quintinite- 3T retained As(v) and did not release it back to water even after an entire month.

Jan 1, 2016

By P. E. Nolan

The disproportionation of carbon monoxide is an important aspect of reduction processes, in the production of carbon filaments for composites, and in the removal of CO from CO,. It can also be a hindrance, causing carbon fouling of equipment and metal dusting. The reaction is thermodynamically favored at lower temperatures, but it occurs slowly. Catalysis of the reaction by transition metals has been examined. A materials science approach to the selection of a catalyst material and of optimum operating conditions is being taken in the present work. Of particular interest is characterization of a catalyst that can be repeatedly regenerated to prevent deactivation in long term use. Experimental data on a less studied catalyst, ruthenium, are reported.

Jan 1, 1992

By Petrus Christiaan Pistorius, Farzin Fatollahi-Fard

The production of titanium oxycarbide – a consumable anode material used in molten-salt processes for electrowinning titanium – from heavy mineral concentrate, such as a high-titania leucoxene and natural rutile is described. The oxycarbide is prepared by carbothermic reduction of the oxide at elevated temperature. Particle size distribution (of the titanium oxide raw material) and temperature have large effects on the kinetics of the reaction, which seem to follow a “shrinking-core” model. It is anticipated that low porosity (in the anode pellets) would be advantageous during electrolysis. Particle size distribution, extent of reaction during carbothermic reduction, and sintering temperature are expected to affect pellet porosity after sintering, and are being tested experimentally.

Jan 1, 2015

By Muhlis Nezihi Saridede, Burak Birol

"Plastic wastes become a huge problem day after day due to the growth of plastic industry. Hence, plastic wastes are used as a raw material for other industries to eliminate this problem. Polyethylene Terephthalate (PET), which is a commonly used for plastic bottles, may be used as a reductant for iron production because of its C and H content. In this study, composite pellets containing iron ore concentrate, flux and reductant were prepared. Crystallized PET bottles and coke were used as reductant after ground. The prepared pellets were reduced at 1400°C for 30 min. and iron nuggets were produced successfully. Usage of waste PET purely as reductant in composite pellets gives a higher metallization degree and proper carbon content than coke or PET and coke mixture.IntroductionPlastics can be seen everywhere, especially at packaging industry in our common life. The increase of plastic usage ends up with an important problem, the increase of plastic wastes. Many studies have been carried out about usage of plastics as reductant in blast furnace such as Ogaki et al.[1], Heo and Baek [2], Saridede [3], Minoru et al.[4], etc. Besides, Kato et al. [5], Nomura and Kato [ 6] and Rongfang et al. [7] have pointed out the use of plastics in coke ovens regarding to its calorific content. In EAF steelmaking, a mixture of coal/coke and plastics can be used as an energy resource instead of only coal or coke. [8] Also, the usage of PET and PC in self-reducing composite pellets increased the reduction rate. [12]PET (Polyethylene terephthalate ), which is commonly used for soft drink plastic bottles, is an important municipal waste due to its C and H content. Its molecular formula is (C10H8O 4)n. Demir and Dincer showed that PET can be crystallized at 250°C to have the ability to be ground to a size of -100 µm. [11]"

Jan 1, 2011