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By Kerri-Ann Hue, Kerry Hasapidis, Ken Babcock, Patrick O'Hagan

"Metallic nanoparticles exhibit properties that are significantly different from individual atoms or bulk materials. Their applications are diverse and have varying uses in areas such as cancer treatment, biochemical sensors, nanoelectronics, and drug delivery. For each application extensive characterization must be performed in order to probe the unique properties of these nanoparticles. In this study, ultra-high resolution mass sensors consisting of MEMs-fabricated, suspended microchannel resonators (SMRs) were used to determine the size and concentration of metallic nanoparticles. With femtogram (10- 15 g) mass resolution, ultra-high resolution mass sensors can weigh individual particles suspended in fluid, and so measure their mass, density, and size. Particle size analysis with these sensors provides excellent accuracy and resolution compared to mature technologies such as light scattering. This technique also provides quantitative information via the ability count particles.IntroductionThe unique electronic, chemical, and optical properties associated with nanoparticles vary with their size, shape, and composition[ 1-4]. These properties are attributed to increased surface area and nanosized mean free path of electrons to the particle surface. Nanoparticle colloidal solutions have been prepared and are commercially available. In recent years, noble metals such as gold, copper, and silver have been extensively researched[5-7]. In order to tailor the optical, electronic, and electrical properties of nanoparticles, size and shape must be controlled. For many applications a monodisperse colloidal solution is ideal. Methods of size characterization include Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and Electrophoretic Mobility Measurements to name a few[6, 8]. Although TEM can provide shape and size distributions, sample preparation requires that samples be dried on a metal grid and cannot be analyzed in solution. DLS uses curve fitting algorithms that while useful for determining mean particle diameters are not ideal for polydisperse colloidal solutions. New technologies are therefore needed to accurately determine the particle size distributions of metallic nanoparticles."

Jan 1, 2011

By Ronald L. Pariani

To date, significant advances have been made regarding the development and commercial implementation of full deposit stripping in the copper industry such as practiced at Copper Refineries, LTD in Townsville, Australia. The paper describes the history and current practice of Electrowinning (EW) plants which may be coupled with solvent extraction. The modular nature and degree of automation are described in relation to the various sizes of operations. Reference is made to the expansion capability of commercial equipment plus associated economics of the mechanical processes for producing full cathode deposits. It is recognized that the technology described may be adaptable to other nonferrous refining areas where feasible. The paper highlights the state of the art in mechanized stripping equipment as applied to current and planned SX-EW plants.

Jan 1, 1987

By W. D. Judge, Z. W. Xiao, G. J. Kipouros

Rare earths have taken a prominent position in the Hi-Tech field after the discovery of the NdFeB permanent magnets. Their use in the magnets sparked miniaturization of the communication devices such as computers and mobile phones and are being considered in many more applications. Potential applications of rare earth elements in energy conversion technologies including wind turbines, photovoltaics, and other renewable energy systems are reviewed, along with sustainability considerations and production processes.

Mar 1, 2017

By J. R. Kiji

The Cerro Matoso S.A. mine and smelter, in the Cordoba lowlands of northwestern Colombia, consist of a dedicated laterite nickel mine, ore blending, drying and an RKEF process to produce high-quality ferronickel. At a project investment of $400M, first production of ferronickel was in September 1982, and in its inaugural year CMSA produced 6,150 tons of contained Ni from a mined ore grade of 3.2% Ni. Initial operational difficulties resulted in a number of furnace run-outs, which impacted ramp up to design ore throughput of 128 dry t/h Since then CMSA has steadily incorporated process improvements and initiatives to take the single line operation to an ore throughput of 175 dry t/h. A second 175 dry t/h line was added in 2001 (investment of US$ 300M) to consolidate CMSA as one of the world's lowest cost Ni producers with an installed annual production capacity of 50-55,000 tons Ni. The most recent addition is commissioning of Phase I of an ore-upgrading project to counteract the effect of declining ore grades. Keywords: Laterite, ferronickel, pyrometallurgy, smelter.

Jan 1, 2004

By Marisa Di Sabatino, Michael Phan Knudson, Mari Juel, Eivind Øvrelid

"A p-type Czochralski silicon ingot doped with boron was characterized for resistivity, minority carrier lifetime, interstitial oxygen, and metallic impurities. Analyses show a peak in resistivity and a dip in lifetime both occur 5 cm from the top of the ingot crown. This peak in resistivity deviates from the expected trend based on Scheil's equation for boron distribution. High concentration of interstitial oxygen in this area suggests that other oxygen-related defects, such as thermal donors and precipitates, may also be present here, and the observed peak in resistivity and dip in lifetime could be attributed to such defects. The low lifetime of 15-30 µs at minority carrier density of 7.5 x 1014 cm-3 is likely due to copper contamination.IntroductionSolar energy resources vastly exceed all other alternative energy resources, ensuring that solar power must play a crucial role in the evolving energy market. The economic viability of solar power in competition with other energy resources depends upon finding efficient, cost-effective, reliable, and controlled methods for solar cell production. In this regard, minimizing waste (such as material with unsuitable electrical properties that hinder solar cell performance) is a vital component of making solar cell manufacturing cost-effective. Impurities affect electrical properties of solar cell silicon in different ways (i.e. [1, 2, 3, 4, 5, 6]). In this work we focus on the role of oxygen and metallic impurities. Understanding oxygen impurities in silicon is critical to solar cell development because oxygen has been attributed with influencing critical electrical properties including resistivity and minority carrier lifetime and thereby potentially hindering solar cell performance or rendering material unsuitable for solar cells.[1, 2] Furthermore, oxygen is a common impurity in the standard type of solar cell silicon, Czochralski (CZ) silicon, due to diffusion of oxygen from the silica crucible into the melt during crystallization. [7] This study investigates the effects oxygen impurities have on the electrical properties of p-type CZ silicon."

Jan 1, 2013

By Toru H. Okabe

As part of a systematic study on the thermodynamic properties of complex nitrides, phase equilibria of the system Li-M-N (M Mg, AI, Ga) at 900 K were investigated. An attempt to determine the thermodynamic properties of complex nitrides was made by using the galvanic cell method, which utilizes LiMgN as an electrolyte under nitrogen atmosphere. The electromotive force (Emf) of ilie cell at temperatures between 800 and 1100 K was measured. Whilc the Emf of the cell at 900 K was measured to be 0.137 V, data discrepancies of ±0.03V were found. It was difficult to determine temperature dependence of ilie Emf. The Gibbs energy change for the reaction, 113 LbN (s) + 1/3 Mg3N2 (s) = LiMgN (s), at 900 K was determined to be tJ.Gor (LiMgN) -13.2 (±2.9) kJ/mol. Using thermodynamic information on ilie binary nitride from literature, the standard Gibbs energy of LiMgN was derived to be AGO f (LiMgN)= - 121 kJ at 900 K. The thermodynamic stability range of nitride was discussed by constructing isothermal chemical potential diagrams that provide a better understanding of ilie stability region of the LiMgN phase. The diagram was found to be in good agreement with the isoiliermal phase diagram determined by ilie alloy equilibration meiliod. Although the obtained data includes large uncertainties, the results provide a better understanding of the iliermodynamic stability of nitrides. The potential application of this complex nitride to nitrogen chemical sensors or a medium for controlling nitrogen potential is also shown.

Jan 1, 2003

By Toru H. Okabe

As part of a systematic study on the thermodynamic properties of complex nitrides, phase equilibria of the system Li-M-N (M Mg, AI, Ga) at 900 K were investigated. An attempt to determine the thermodynamic properties of complex nitrides was made by using the galvanic cell method, which utilizes LiMgN as an electrolyte under nitrogen atmosphere. The electromotive force (Emf) of the cell at temperatures between 800 and 1100 K was measured. While the Emf of the cell at 900 K was measured to be 0.137 V, data discrepancies of ±0.03 V were found. It was difficult to determine temperature dependence of the Emf. The Gibbs energy change for the reaction, 113 Li3N (s) + 1/3 Mg3N2 (s) = LiMgN (s), at 900 K was determined to be !'J.Go, (LiMgN) = -13.2 (±2.9) kJ/mol. Using thermodynamic information on the binary nitride from literature, the standard Gibbs energy of LiMgN was derived to be !'J.Go f (LiMgN)= - 121 kJ at 900 K. The thermodynamic stability range of nitride was discussed by constructing isothermal chemical potential diagrams that provide a better understanding of the stability region of the LiMgN phase. The diagram was found to be in good agreement with the isothermal phase diagram determined by the alloy equilibration method. Although the obtained data includes large uncertainties, the results provide a better understanding of the thermodynamic stability of nitrides. The potential application of this complex nitride to nitrogen chemical sensors or a medium for controlling nitrogen potential is also shown.

Jan 1, 2003

By Christoph Zschiesche

Managing complex material streams within a lead smelting/reduction process has a long history at Aurubis. After modernization of the secondary lead smelter in 1991, Aurubis operates an electric furnace and a Peirce Smith converter to process complex secondary materials. This process links the copper and the lead metallurgy allowing Aurubis to properly combine primary and secondary process lines to optimize the processing of complex raw materials and smelter intermediates. However, combination of copper and lead metallurgy processing requires a continuous evaluation as raw material quality and composition varies. This paper describes Aurubis lead smelter processing and provides some fundamental considerations to optimize the lead processing, in particular with aspects related to speiss formation

By T. Shibasaki, S. Kamio, K. Kanamori

"Mitsubishi Process has been proven through fifteen years operation to be highly productive, cost efficient and easy to abate environmental requirements. However, in order the process to remain competitive from now on, it should also be adaptable to a variety of varying conditions. Various test works have been conducted from such a stand point of view and some of the new concepts have been implemented to the actual operation.The paper discusses the adaptability of the process to the change of concentrate grade with respect to copper and also impurities, acceptability of the secondary materials and the potential to increase unit capacity. IntroductionThe first commercial plant of Mitsubishi Process with 48,000 mt copper annual capacity started its operation at Naoshima Smelter of Mitsubishi Metal Corporation in 1974, and the second plant with 65,000 st annual capacity started in 1981, at Kidd Smelter, Timmins, Ontario, now Kidd Creek Division of Falconbridge Limited 2. These plants have increased their capacities to 90,000 mtpa respectively by adding oxygen and acid plant capacities while maintaining the original furnace design uncharged. Thereby both smelters have established more cost efficient operations. (3), (4)Mitsubishi Process applies so-called multi-furnace continuous system. Figure 1 shows conceptual flowsheet. Backgrounds that required and justified the development of such system are as follows:"

Jan 1, 1988

Direct electrowinning is an electrochemical process which has been developed for the extractive recovery of copper from dilute, acidic leach solutions. In passing through a thin particulate coke cathode. copper is reduced and electrodeposited in a thin layer forming a solid copper-coke sheet. The product is melted in a furnace to separate the coke, then the molten copper is fire refined to produce a salable product. A description is given of a prototype unit which is designed to treat 20 gpm leach liquor and recover over 100 pounds of copper per day. Economic analyses show that in a commercial facility producing about 25.000 TPY copper.*the direct electrowinning process has lower overall cost than either conventional iron-cementation or the newer liquid ion exchange-electrowinning when the leach liquors contain less than 2 grams per liter of copper.

Jan 1, 1976

By O. Durand

The Cerro Verde Hydrometallurgical Plant, located at Arequipa in the southern part of Peru, started its operation in 1977 with a design capacity of 33,000 MT/year of copper cathodes. The plant has treated 61,055,000 MT of ore mainly oxides with a content of 1.01% total copper and 0.67% of soluble copper. The leaching plant has three pads that produce 4.0 gpl copper solution. The solvent extraction plant has four trains with three extraction stages, two stripping stages with a single mixer in all stages. The mixer-settlers are 316 stainless steel and the pumps are vertical turbines. The flowrates of 1,300 gal/mil of aqueous and 1,300 gal/min of organic at a 1/1 ratio. The electrowinning plant contains 208 commercial cells and 18 starting sheet cells. Each cell has 47 anodes and 46 cathodes. In addition to describing the hydrometallurgical plant, this paper also mentions efforts directed at reducing costs and improving operations. The initial results from leaching secondary sulfides, which started October 1985, are also discussed.

Jan 1, 1987

By K. Iwami, K. Abe

"Onahama Smelter and Refinery has been operated-since 1965 arid currently produces 243,000 metric tons per year of cathode copper. The Onahama tankhouse consists of conventional-type No.1 and 2 tankhouses with the capacity of 123,000 metric tons per year and No.3 tankhouse with 120,000 metric tons per year, adopting jumbo tank system, using hazelett anode respectively.In October, 1996, for the purpose of improving the - anode verticality, new anode copper body press machine has been installed in No.1, 2 tankhouses; by increasing Walker type anode copper weight by 35kg to 365kg. Consequently, it is possible to raise current density from 191 to 222 A/m2 and the No.1 and 2 tankhouses capacity was increased by 15,000 metric tons per year to 138,000 metric tons per year.At present, the refining capacity is 258,000 metric tons per year in total including No.3 tankhouse.This figure is the largest one in Japan.IntroductionSince the Onaham tankhouse was put into operation in 1965, the cathode copper production has increase with much labor cost saving.The following two cases to increase Walker type anode copper weight by 35kg to 365kg were studied.a) To increase the cathode copper production by raising current density.b) To save the labor cost by prolonging the anode cycle in order to decrease the exchanging time of electrodes.So the electrolytic tests were carried out to confirm· the effect of current efficiency, cathode copper quality and working conditions for space adjustment.As a result, we concluded that it was indispensable to introduce the anode body press machine to keep usual current efficiency and cathode copper quality with same workers, and to be possible to increase cathode copper production.In addition, the high-speed press machine was needed to maintain same working time and which specifications were decided through various investigations. In October 1996, the new anode body press machine made by Kawazoe Machine Works, Ltd. has been installed in No.1 tankhouse."

Jan 1, 2000

By J. M. Demarthe

MINEMET RECHERCHE (IMETAL Group, formerly Le Nickel-Penarroya-Mokta) has studied on a laboratory scale and patented a new process to recover metal values -copper- from sulphide ores and concentrates. It combines a cupric leaching, solvent extraction and copper sulphate electrowinning according to the main following steps - A direct and selective leaching of copper sulphide ores or concentrates at atmospheric pressure with cupric chloride to form cuprous and ferrous chlorides and elemental sulphur. Pyrite remains in the sulphur residue. - The leach solution is separated into two parts -In the first one, air is injected to precipitate iron as goethite. The oxidation step can be easily realized at atmospheric pressure by maintaining an excess of cuprous and-ferrous chlorides in the liquor. Copper is extracted from the second part as cupric ion by an LIX reagent. Direct injection or air in the mixing chamber maintains good extraction conditions, so that only one mixer settler is required. - Iron, in the form of ferrous ion, is not coextracted. - Copper is stripped from the organic phase, transferred into a sulfuric phase and sent to sulphate electrowinning cells, which are now conventional in copper metallurgy. - Only electricity and air are required. After a feasibility study, the next step will be to develop it on a pilot and commercial scale.

Jan 1, 1976

By N. A. Warner

Fundamental studies on the reaction of limestone or dolomite at high temperature with S02 are extended to the realm of large scale primary copper smelting. Whereas flue gas desulfurisation in the electric power utility industry is concerned with S02 concentrations normally less than 0.5 percent, high temperature smelting gases can have S02 levels approaching 100 percent. The reaction involved is very exothermic so proposals are made in this paper for returning the heat generated in sulfur fixation directly back to the copper smelting process. This integration leads to metal production with lower energy requirements than current technology. The anhydrite reaction product can either be disposed of locally with minimum adverse environmental impact or upgraded to a value-added product. It is assumed, of course, that no viable market exists to support sulfuric acid production.

Jan 1, 1996

By A. S. Usmani

The flow associated with the pouring of molten metal into moulds has been modelled on the basis of certain simplifying assumptions. A finite element based Navier-Stokes equation solver has been used to analyse the flow. The velocities obtained from the Navier-Stokes equation solver are used to advect a pseudo-concentration function for modelling the fluid front. A simple problem with a known analytical solution is solved first to test the model. Subsequently, several more examples with varied geometrical configurations are modelled, including one with curved flow boundaries.

Jan 1, 1992

By Klaus Gamweger

"This paper introduces an innovative solution to open and close the tap hole of different furnace types in the copper industry with a slide gate system. Two plates with defined drilled holes are slid against each other, which enables effective starting and stopping of the copper flow as well as throttling. Typically, the copper is poured via a tap hole into a launder system by rotating the furnace into an appropriate position. Control of the casting rate is also performed in this manner. Or, in case of stationary furnaces the tap hole is opened by oxygen lancing and closed manually with a clay- or copper-cone. These procedures show a lot of disadvantages including splashing, oxygen pick-up, and energy losses as well as a severe danger for the working staff. All these problems can be overcome with an appropriate slide gate system.IntroductionThe control of the casting rate of a copper anode furnace usually is performed by rotating the furnace into an appropriate position. This implies that the taping starts with the tap hole at a very high position. Copper splashing and an uncontrolled oxygen pick up are - with several more disadvantages - the consequences. RHI AG has developed an innovative solution for copper applications to open and close the tap hole with a slide gate system which allows also an accurate control of the flow rate. By using this system it is possible to start the casting procedure with the tap hole at the deepest position, directly above the launder. This paper presents this new slide gate system in detail and shows the advantages in production and safety issues."

Jan 1, 2012

By I. M. Richardson, M. Janssen, I. J. Bennett, V. A. Popovich

The most critical processing step during the manufacture of screen-printed crystalline solar cells is firing aluminium and silver contacts, which generates residual stresses and solar cell bowing. In this paper, an alternative Ag contact formation mechanism is proposed and aspects related to electrical contact properties, residual stresses and layer delamination are investigated. It is found that there are two main processing parameters affecting the uniformity and delamination of the Ag/Si interface, namely the peak firing temperature and the silicon surface roughness. Silicon surface polishing gives a better wetting of the silicon surface by the glass layer, resulting in a good contact and lower incidence of large voids, compared to the case of highly textured surfaces. The non-uniformity in the glass layer and large voids at the Ag/Si interface (in the case of a textured surface) are expected to have a negative effect on the mechanical strength of the solar cell.

Jan 1, 2015

By Mao Chen, Tim Evans, Zhixing Zhao, Weidong Zhang, Baojun Zhao, Dongqing Wang

High temperature softening behaviours of iron blast furnace feeds (sinter, lump and pellet) have been determined under conditions simulated to the blast furnace. The industrial samples were packed with sandwich structure (coke / ore / coke) in graphite crucibles and 30 CO / 70 Ar gas mixture was blowing directly through the bottom of the crucibles. The displacement and temperature were continuously recorded simultaneously to construct the softening curves. Separated quenching experiments were also carried out at selected temperatures under the same gas atmosphere. The temperatures were selected corresponding to the turning points of the softening curves. The phase assemblages and composition of each phase in quenched samples were analysed by Electron Probe X-ray Microanalysis (EPMA). The proportion of the liquid formed at temperature was obtained from the backscattered electron images. The deformation characteristics of these complex multi-phase materials are shown to be related directly to the phase assemblages of the samples and the microstructures. FactSage was also used to assist the predictions of liquid / solid fractions and their compositions.

Jan 1, 2015

By Klaus Bauckhage

Phase-Doppler-anemometry (PDA)-measurements have to be taken from representative measuring positions from inside the spray cone, helping - with the support of simulated data of improved process models - to describe the multiphase flow situations within the spray cone - and accordingly to that - the heat transfer conditions for the rapid cooling and (partly) solidifying melt droplets before their impact onto the substratddeposit. Simulations and PDA-measurements thus give the base to confirm the hypothesis of the existence of a semisolid mixed-layer and it's influence on the resulting material structure during compaction. The dispersed particles in the spray cone exhibit a cooling and solidification process within a split of a second, which leads - as far as the particles solidify - to a dendritic structure with very short dendritic arm spacings. This causes within the particles extremely short distances for the following equalizing diffision processes taking place on a high temperature level (between liquidus and solidus) in the semisolid mixed-layer of the deposit and explaining the short residence times within this zone of only seconds up to a few minutes. This and the fact that the globular structure of the mushy zone (in the semisolid mixed-layer) leads to an unidirectional crystallization process over very short distances also explains the chemical and morphological ,homogeneity of the sprayed material. The dynamics of these process steps, the very special buffer function of the mixing layer during parameter variations as well as the controlled cooling process of the preform in order to avoid hot cracks influence the quality of the material. Due to the necessity of measuring and controlling the particle bound mass-, momentum- and enthalpy- fluxes to the deposit the PDA-technique has been adapted and modified in order to receive in-line and (in the future) also on-line data from the dynamics of the multiphase flow conditions within the spray chamber.

Jan 1, 1999

By R. W. Adams

A new process has been developed for leaching zinc sulphide concentrates at atmospheric pressure using air or oxygen plus nitrogen dioxide in dissolved or gaseous form as? an oxygen carrier. The process is flexible and can cope with variations in the degrees of retention and regeneration of dissolved nitrogen dioxide in the leaching phase. By controlled addition of concentrate a leach solution with low residual nitrate concentration can be produced. Following separation by filtration of unleached solids and elementa1 sulphur and conventional oxidation/precipitation of dissolved iron, the leach liquor can be treated with metallic zinc to remove the remaining nitrate and other meta111c impurities such as copper, cadmium and cobalt to provide a solution suitable for electrolytic recovery of zinc. Pilot scale testing of the process .has given zinc recoveries in the high nlnet1es, production of a hi.gh grade jarosite-free Pb/Ag residue (50% Pb.) and a saleable high grade of elemental sulphur. .A wide range of concentrates can be treated containing substantial levels of lead and copper as well as zinc. Indicative cost estimates suggest that the new process is competitive with alternative procedures such as pressure leaching.

Jan 1, 1990