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By Jason H. Nadler, Jason A. Kulpe, Stephanie J. Lin

"A numerical method has been developed to predict the microstructural characteristics of reticulated metal foam. The porosity of this foam is derived from sacrificial template particles of known particle size distribution, which are incorporated with other precursor components. In this approach, a porous structure is numerically generated starting with Powell's sphere packing algorithm. The resulting stochastic structure has characteristics similar to those of corresponding metal foam. Deterministic inter-sphere connections are calculated to more accurately model the pore morphology that evolves during thermochemical synthesis. Estimations of pore morphology and specific surface area of the simulated material are compared to lab-synthesized materials composed of equivalent constituent compositions. In addition, the effect of template particle size, inter-sphere connections, and the geometric constraints on pore morphology and permeability are investigated to refine microstructural evolution and design.IntroductionReticulated foams, characterized by their interconnected pore network, can be obtained by incorporating spherical sacrificial template particles into precursor materials followed by template removal processes. The resulting structure is composed of contiguous spherical pores whose morphologies reflect those of the original templates. Based on some of the unique features of this synthesis approach, a methodology is introduced in this work whereby these foams are digitally constructed using experimental data from the template particle sizes and precursor formulation. Digitally constructed porous structures can then be compared to their laboratory synthesized counterparts through the quantification of structural features such as porosity and surface area per unit volume, which in tum are used to inform the foam's fluid transport propertiesThe spherical template particle packing algorithm developed here is adopted from Powell's work [1], which also includes approaches to obtain percolation and density in random packings [2]. Gervois gives a mathematical development for the stereological sectioning of packed hard spheres [3]. Stereological sectioning facilitates determination of relevant three dimensional morphological properties from two-dimensional data [4]. Studies on the sphere distribution size and the related particle packing density and coordination number results are studied in [5, 6]. Lastly, Kato describes a sintered neck structure, which is used with these packings [7]. This neck structure, as a model of the particle shape following heat treatment, is implemented here in a similar manner. A strong difference between the available literature and the methodology here is that spheres are packed to ultimately represent porous space, not rigid solid space."

Jan 1, 2011

By A. K. Kyllo

A study has been carried out on the dusts from Hudson Bay Mining and Smelting's Flin Flon copper smelter. The aim of the work was to determine the mechanisms of dust formation and the deportment of the various constituents. The work concentrated on the copper converters, but the electrostatic precipitators and baghouse also clean the reverberatory furnace off gas, so some mixing will have occurred. The dust composition was found to vary with distance from the furnace, and to be made up of three major components: solidified droplets, unreacted flux, and condensed particles. The solidified droplets were formed from material ejected from the converter during blowing, while the flux was blown out of the converters immediately after charging. The condensed particles contained the majority of the lead and zinc, as well as the volatile impurities. There was also a significant soluble content of the dusts, increasing with distance from the furnace. The condensed material may be separated from the remainder by a simple washing and sizing technique.

Jan 1, 1996

By D. J. Chaiko

Certain radionuclide ions (e.g., TcO4) exhibit unusually strong Affinities toward the polymer-rich phase in aqueous biphase systems generated by combinations of salt solutions with polymers such as poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG). Thus, aqueous. polymer ,phases could potentially be used to selectively extract these ions during pretreatment of radioactive tank wastes at Hanford. To help develop a fundamental understanding of the interactions between various ions and polymers in aqueous solution, interaction enthalpies between sodium -perrhenate and a random copolymer of PEG and PPG (UCON-50) were measured by microcalorimetric titration. An entropy compensation effect was observed in this system in which changes in enthalpic interactions were balanced by entropy changes such that the interaction free energy remained constant and approximately equal to zero.

Jan 1, 1999

By B. Abedian, L. M. Racz, S. R. Berry, R. W. Hyers

"The presented work represents an effort to improve understanding and prediction of turbulent flow inside electromagnetically-levitated droplets. We show that the flow field in a test case, a nickel droplet levitated under microgravity conditions, is a low Reynolds number turbulent flow, i.e. in the transitional regime between laminar and turbulent. Past research efforts have used laminar, enhanced viscosity, and k - E turbulence models to describe these flows. In our study, we compare the RNG algorithm to laminar and k - E turbulence model results. We show that accurate description of the turbulent eddy viscosity µr is critical in order to obtain realistic velocity fields, and that µr cannot be uniform in levitated droplets. In the RNG method there are no characteristic length or time scales associated with the flow, thus allowing such anisotropic features to be captured. We perform calculations and analyses for two cases (1) a small, non-deforming, spherical nickel droplet and (2) a deforming, oscillating droplet. In addition to flow field calculations, we compare numerically-obtained surface tension and viscosity values to those obtained experimentally by the oscillating drop technique.IntroductionElectromagnetic levitation (EML) is a containerless processing technique for conductive materials. Its advantages are the avoidance of contamination or chemical reaction at container walls and the ability to perform long-term experiments in a metastable state. Because of its current limitation to small sample sizes, its primary use is in the laboratory. One application of interest is the measurement of thermophysical properties of undercooled liquid metals [1, 2, 3, 4]. In EML, a sample weighing approximately 1 gram is positioned inside an electromagnetic field generated by alternating currents flowing through an axisymmetric water-cooled copper coil. The coil must be designed appropriately so that thesample levitates in a stable manner.Traditionally, mathematical modeling has been performed in tandem with both earth-and spacebound electromagnetic levitation experiments, in order to determine the effect of the magnetic field on material and flow characteristics [5, 6, 7, 8]. These calculations are important because they allow design, planning, and correct interpretation of experiments. In addition, the calculations are of fundamental scientific interest, as they can be applied to other electromagnetic materials processing applications [9]."

Jan 1, 1999

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 Sedef Pinar Basag, Onuralp Yucel, Ahmet Turan

Niederschlag process is commonly used to produce metallic antimony. The process is a metallothermic process which is conducted in one step for metallic antimony production. Using this method Sb2S3 is mixed with coal and metallic iron and subjected to reduction. During heating, antimony sulfide is decomposed and sulphur combines with iron to form the matte phase. Metallic antimony is collected at the bottom of the crucible. In this study, evaluation of Sb2S3 concentrate, extracted and obtained from West Anatolian Region of Turkey was investigated by using Niederschlag process. The reductant stoichiometry, reduction temperature and duration were carried out in the experiments. Chemical analysis methods by using atomic absorption spectrometry (AAS) and X-ray diffraction spectrometry (XRD) techniques were used for the characterization of the concentrate, metallic nuggets and matte phases.

Jan 1, 2016

By Laszlo Kadar, J. D. Lavers

"In the continuous casting of aluminum killed steel, the tundish nozzle often experiences clogging problems. Water model studies have shown that the clogging problem is dependent on the flow pattern in the nozzle entry region. In particular, the flow can separate at the entrance to the nozzle, leading to the development of a recirculation region. Although a nozzle can be designed such that no recirculation develops, even a small misalignment from the vertical positioning of the nozzle may render the design ineffective.To reduce the possibility of nozzle clogging, the recirculation zone must be reduced or eliminated. This may be achieved by moving the fluid downwards or raising the turbulence level in the separation region. In the case of a tundish nozzle, it is proposed that this can be achieved by using electromagnetic forces.To generate the required electromagnetic force, two systems are considered. The first is based on injecting a DC current; the second by using electromagnetic induction. Both methods are described in this paper. Order of magnitude calculations are provided to illustrate that both methods are essentially feasible. The performance of each method in terms of modifying the turbulent flow characteristics in the nozzle entry region is then examined using a numerical model. It is shown that both methods can greatly reduce the recirculation zone. A cylindrical nozzle was chosen for the model studies since it represents a worst case situation.On the basis of the model studies, it can be concluded that whereas both of the proposed methods have the potential to reduce the troublesome recirculation zone, the induction method appears to be simpler in terms of practical implementation."

Jan 1, 1999

By M. S. Moats

Galvanic stripping, in conjunction with solvent extraction, has been proposed as a technical option to the challenging problem of iron removal in certain hydrometallurgical processes. The galvanic stripping process is based on the ability of a solid metal to directly reduce ferric ion to the ferrous state in an organic media. Stripping the iron into the aqueous phase is then easily accomplished. Previous work has shown the reaction kinetics and efficiency are affected by such operating parameters as water and oxygen contents, temperature, time and metal reductant. In this study, the optimum operating range for some of these variables was determined. Both zinc and iron metal were used in the separate stripping of iron from D2EHP A. Reasons for the differences in the extent of the reaction obtained using the various conditions are discussed.

Jan 1, 1996

By C. W. Whitten

Solis from an abandoned Pb battery processing facility were characterized prior to the selection of the extraction technique. Reflected light microscopy and electron beam methods were used to locate Pb-bearing phases and to quantify the compositions of the phases. It was found that the soils are composed primarily of quartz and feldspars with minor amounts of iron and titanium oxides. Lead is primarily present as an oxide or sulfate that is associated with the silicate minerals. Specific phases identified were PbO; Pb02; cerrusite, PbCO3; angleslte, PbSO4; galena, PbS; and magnetoplumbite, 2PbO3Fe2O3; or plumboferrite PbO2Fe2O3?

Jan 1, 1989

An iridium oxide coated titanium electrode was tested as anode in copper electrowinning. Initial results confmed that the DSA-type anode was significantly more active for oxygen evolution than traditional lead anodes. However, during longer runs, the anode potential was observed to increase linearly at a rate of 220 mV/year. Scanning elecuon microscopy (SEM) and energy dispersive spectroscopy (EDS) showed that the anode passivation could be attributed to elecuochemical dissolution of the coating. The effect on the anode potential of organic additives (glue and thiourea) and lead in solution was also examined. A preliminary economic evaluation of the anodes is given.

Jan 1, 1992

By J. W. Matousek

Cobalt behavior in pyrometallurgical processes is traditionally analyzed using slaglmatte distribution coefficients as functions of matte grades or matte iron contents. L(s/m) = (%Co) I [%Co] = f [%CuNi] or f [%Fe] The method is inconvenient to use in predictive mass balance work because of the interdependence of assays and mass quantities. An alternative procedure is proposed based on cobaltliron ratios for slags and mattes: Js = (%Co) / (%Fe), Jm = [%Co] / [%Fe], and J, = b + m [Jm]

Jan 1, 1993

By Bingyi Bai, Lifeng Yang, Yanling Guo, Jieyu Zhang, Guoding Gao

In terms of special resources with iron, niobium and rare earth coexisting in Baiyuneboite, the new smelting technology of ferrocolumbite was studied. Reduction experients for the Baiyuneboite and explores ore phase change of Baiyuneboite in the process of reduction was conducted with graphitic carbon as the main reducer and a temperature below 1000 ℃. Moreover, it studies the influence of reducer, roasting temperature and grind fineness on the reduction as well as focuses on the evolution course of iron phase. Through the analysis on in-situ XRD of the raw ore and carbon addition ore, it also develops microstructure change rules of Fe ore phase and ore phase of paragenetic elements for composite ore(Ca, Si, Nb, F) in the process of reduction roasting. In addition, the impacts of temperature on the reduction process are also discussed. With regard to minerals of different particle sizes, the thesis will explore their ore phase changes and microstructures after 10 hours’ reduction under 900 ℃.

Jan 1, 2015

By Jonkion M. Font

Due to the known disadvantages of the use of iron silicate slag in the nickel converting stage, i.e., high metal losses, high magnetite content, and low fixation of impurities in the slag, the development of the new proposed "ferrous calcium silicate slag" for smelting and converting processes of nickel is very promising. Hence, considering the successful experimental results of using CaO base slag for the nickel smelting process, a study based on a detailed comparison for the phase equilibrium, and the minor elements distribution between the Ni3S2-FeS matte with either FeOx-CaO or FeOX-Si02 base slag was investigated. The main results are summarized as: no difference in the nickel losses between both slags was found at high nickel content in the matte, and the fractional distribution analysis for arsenic and antimony pointed out their preferential fixation in the calcium ferrite slag rather than in the iron silicate slag. Considering the energy and pollution issues, the technical feasibility of using calcium ferrite slag in a converting process of the Bessemer matte will have a prominent future for the nickel industry.

Jan 1, 2003

By Signe Kjelstrup, Leiv Kolbeinsen, Marit Takla, Odne Burheim

"This paper presents a Seebeck-type solid state thermoelectric power generator unit, designed to investigate the possible recovery of radiant waste heat at a silicon plant in Norway where roughly 703 of the total input energy leaves the process as waste heat. The unit is 0.5 m x 0.5 m and is built of 36 commercially available thermoelectric devices based on bismuth telluride p - and n - type semiconductors. Thermoelectric devices directly convert fractions of a heat flux into an electric current (and vice versa) and may therefore be convenient for recovery of waste heat when the heat source is discontinuously available. The purpose of the thermoelectric unit is to give a proof of principle of direct thermoelectric energy conversion on a large scale. We present the initial test results for the generator. At an average temperature difference between the heat reservoir and the heat sink of 98°C, we measured an open ciruit potential of 23.44 ± 0.06 V and the matched load power output was 39.4 W. At a temperature difference of 220°C, we predict the generator open circuit potential to be 40.8 V, which corresponds to an efficient Seebeck coefficient of 242 µV /K, and matched load power output to be 120 W.IntroductionThe world's power demand increases, driven by population growth and increase in living standards and simultaneously global warming is recognized as one of our most serious environmental problems. According to the International Energy Agency[l], the industrial sector accounted for approximately one third of the total global power consumption in 2005. Increasing the energy efficiency of industrial processes thus represents a benign and substantial route for addressing environmental concerns and energy security.In accordance with the second law of thermodynamics, all real processes are associated with lost work which is energy being dissipated as heat to the surroundings[2]. Improving the energy efficiency of industrial processes is about finding the process path associated with a minimum of lost work. The more evenly the losses are distributed, the smaller are the losses [3, 4]. In addition, exploiting the unavoidable waste heat will contribute to improve the energy efficiency. The waste heat may be utilized for heating purposes and/or it can be upgraded to work for instance via some sort of heat engine."

Jan 1, 2012

By Philip Arthur

The ISASMELT process is making a significant contribution to the global metals industry. ISASMELT furnaces are now operating successfully in eight different countries and treating approximately 3 million tonnes of concentrates and secondary materials per year. The process is currently used in both lead and copper smelting. The most recently commissioned plants were in Germany and China, one for treating scrap copper and the other treating low-grade copper concentrates. The Copper ISASMEL T furnace ("CIF") at Mount Isa Mines Limited ("MIM") has continued to set new operational records, with throughput of more than I million tonnes of concentrate per year and very low operating costs. This paper summarises the latest operational data from the Mount Isa Copper ISASMELT plant and outlines the successful approach to industrial R&D taken by MIM in the development of the ISASMEL T process.

Jan 1, 2003

By Wei Gao, Qing-cai Liu, Cun-fang Lu, Jian Yang, Hinmi Zheng

"The mode of occurrence of sulfur and mercury in 57 Chinese bituminous coals have been examined using X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), and Zeeman atomic absorption mercury spectrometer. Mercury levels in coal are related to the geographic location of the coals and types of the coals. A synthesis of result indicated that most likely occurrence modes of mercury in high-sulfur and high-mercury coals are in solid solution in pyrite. Our study from 57 coal samples showed that most values of mercury concentration in coal varied from 100 to 1000 ng/g with an average of approximately 500ng/g, and mathematical model about correlation between mercury and sulfur was gained by mathematical statistics. This is apparent that mercury and sulfur vary concomitantly from coal data (table 3) , the high correlation between them in all coals at confidence of 95% ( a=0.05 ) .1. INTRODUCTIONThere contained about one trillion ton abundant coal resources in China. As a leading level of proven coal reserves in the world, the coals mainly distributed in north China and northwest China, especially in Shanxi, Guizhou, Shanxi provinces and Inner-Mongolia autonomous region. At the same time, China has the largest production and consumption of coal, and has the output of coal nearly accounted for 37 percent of the world's production. Coal-fired power plants are the major source of energy generation in China, and the proportion of coal combustion is up to 75 percent in the total energy configuration. Therefore, the mercury pollution caused by coal-fired has become a topic of wide-spread discussions since 1990. The contamination of mercury of human activities accounted for 10 to 30 percent [1], and the mercury emissions of coal-fired flue gas has made the greatest contribution to the pollution of atmosphere[2] In the past 30 years, the global increasing concentration of mercury pollutant in atmosphere maybe result from coal combustion[2]. The mercury emissions caused by coal-burning has become the main reason of China's mercury pollution, and the characteristics of mercury pollution is closely related to China's energy configuration, additionally, the features of mercury pollution have changed from the point pollution in 1970's to diffused pollution today[3]. Mercury can be found in various types of coals, and it is evaporated into gas phase during the combustion process."

Jan 1, 2011

By Philip Arthur

The ISASMELT process is making a significant contribution to the global metals industry. ISASMELT furnaces are now operating successfully in eight different countries and treating approximately 3 million tonnes of concentrates and secondary materials per year. The process is currently used in both lead and copper smelting. The most recently commissioned plants were in Germany and China, one for treating scrap copper and the other treating low-grade copper concentrates. The Copper ISASMEL T furnace ("CIF") at Mount Isa Mines Limited (UMIM") has continued to set new operational records, with throughput of more than I million tonnes of concentrate per year and very low operating costs. This paper summarises the latest operational data from the Mount Isa Copper ISASMEL T plant and outlines the successful approach to industrial R&D taken by MIM in the development of the ISASMEL T process.

Jan 1, 2003

By Claudio Toro, Alex Moyano, Jonkion Font, Carlos Caballero, Pedro Morales

"Codelco-Chile in the last decade has carried out industrially-oriented research as an alternative to the traditional batch-type converting process. In a first stage carried out preliminary evaluations in a rearranged Peirce Smith (PS) converter, and then an exploratory test in a “Convertidor Teniente” (Teniente converter, TC) for the Codelco-Chile Continuous Converting Process. However, the validation test for this process in the TC was delayed up to the second quarter of 2007 where the validation studies were done satisfactorily.Thus, the objective of this paper is to present the results of the campaign tests validating the Codelco-Chile Continuous Converting Process in the TC1 of the Codelco Norte smelter.The results of charging the solid or liquid matte or high grade matte (“white metal”) by Garrgun, or by mouth of the 22 m x 5 m TC1 are presented. Some features of the industrially validated process are discussed, and the pilot test results of the matte injection are also presented."

Jan 1, 2009

By M. K. Mohan

During the processing of metals like Cu, Ni, Co, large quantities of solutions, which contain co- products such as Sb, Cd, Pb etc. are generated. These solutions if processed to recover the metals help in conservation of metals as well as environment preservation. The present study was taken up to recover antimony from process solutions using zeolites. The effect of pH of the solution, time and type of zeolite viz., chabazite, mordenite, erionite and clinoptilolite on the sorption of antimony was investigated. Rate of sorption increases with pH and about 77-pct. antimony sorption was observed with chabazite at a pH of 6. Optimal conditions were established for the maximum recovery of antimony fiom process solutions. The mechanism of sorption for Sb was proposed in terms of adsorption and intraparticle diffusion. The calculated adsorption constants from Langmuir and Freundlich equations indicated that the adsorption of antimony on chabazite was strong.

Jan 1, 1999

By R. Nilsson

In the present work, an assessment of the sulphide capacities of a number of binary and ternary slag systems have been carried out in the light of a sulphide capacity model. The model is based on the expression: {CS- exp (-A G °/R T) ? ao2 / fs2-} where AGO is the standard Gibbs energy change for the above reaction, ao2 is the activity of oxygen ions and f, is the activity coefficient of the sulphide ion in the slag. In the present model, the ratio (ao2/fs2) is optimized for the experimental data available in literature. The systems assessed are the binaries MnO-SiO2, CaO-SiO2, Al2O3-CaO, as well as the ternaries CaO-Al2O3-SiO2 and CaO-MnO-SiO2. In the case of all these systems, the experimental data available in literature were complemented by measurements carried out at the Division of Theoretical Metallurgy. The sulphide capacities of some FeO- containing binary, ternary and quaternary slags are also examined. The potentiality of the model to estimate the sulphide capacities of complex slag systems from binary and ternary data is demonstrated.

Jan 1, 1996