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By Kazuteru Tozawa

Surface tension, density and viscosity coefficient of acidic copper sulfate solutions simulating electrolyte solution for electrolytic production of copper have been measured and are summarized as a function of the solution composition and temperature. Nickel sulfatc is taken to be a representative coexisting sulfate that affects the physical properties of the copper sulfate electrolyte solution. The sulfates in the solutions, including sulfuric acid, increase the physical properties under consideration. Gelatin, representing organic additives for electrolyte solution, was found to sensitively affect the surface tension of the solution at low concentration of up to 200mgIL. The surface tension was markedly lowered by the addition of gelatin and the increasing concentration of gelatin led to a more pronounced decrease in the observed values. The surface tension gradually increases with time after addition of gelatin and the increase is enhanced by higher acid concentration and higher temperature. The observed change in the surface tension is considered to reflect the preferential adsorption of gelatin to the bubble-solution interface and the decomposition of gelatin due to hydrolysis to form various molecules having smaller molecular weights.

Jan 1, 2003

By Dilip Banerjee

"This paper discusses the Advanced Technology Program (ATP)'s support over the last decade to the development and use of process modeling as a tool to address some of the challenges faced by the U.S. metal casting industries. A particular focus will be given to highlight how process modeling can be used to improve the manufacturability of components needed for high performance and critical applications. The challenges associated with the design and production of thin-walled, cast parts with intricate and complex internal geometries will be discussed. Modeling issues associated with the control of the final grain structure in the solidified parts will also be addressed. This paper will describe the advantages of using appropriate mathematical models for designing new alloys for use in various applications.Finally, the role that ATP has played in uplifting the U.S. technological base through partnerships with industry and academia in high-risk research in order to bring to market new and improved products for the broader benefit of the nation will be discussed.ATP's BackgroundIn the 1980s, U.S. industries were losing market share to low-cost, high-quality manufacturers from Asian countries. Corporate leaders and policy makers determined that in order to sustain and grow market share, U.S. industries needed to improve their competitiveness and productivity through product and process innovation. There was evidence that companies were systematically under-investing in leading-edgetechnologies and failing to complete the development of new technologies [l]. There were also arguments in academic circles that pointed to a potential market failure in the area of early-stage technological developments. These concerns provided impetus for creation of the Advanced Technology Program (ATP) within the National Institute of Standards and Technology through the Omnibus Trade and Competitiveness Act of 1988. Through a rigorously competitive, cost-shared partnership with industry, ATP fosters the development and broad dissemination of high-risk technologies that offer the potential for significant broad-based economic benefits to the United States."

Jan 1, 2004

By Gordon A. Irons

"Powder injection for melt refining is widely practiced in the steel industry, and is gaining acceptance in the non-ferrous industries. In these commercially-important systems, the thermodynamics and kinetics may be very complicated. More than one element may be removed by refining, and often the refining agents are not just one compound. In this paper, the thermodynamic and kinetic aspects of these processes are reviewed. A number of examples are given, such as the desulphurization of iron with a variety of reagent mixtures, and selenium removal from copper with several different reagent combinations.IntroductionI am very pleased and honored to present a paper at this Symposium recognizing the many contributions of Professor Howard Womer. Even at the time I was an undergraduate student, the WORCRA process was part of the curriculum. I remember at the time that I was fascinated by the concept, and due to it and the many other rapid developments in Process Metallurgy, I chose it as my field of study. I think the Symposium is testimony that Professor Womer has touched the lives of many others as well.My original assignment was an overview of the basic aspects of gas and solids injection. However, I reviewed most of this material at the Savard/Lee Symposium [1]. In the present paper, I will present some of the basic issues related to refining with powder injection, using work that we have recently completed in both ferrous and non-ferrous systems."

Jan 1, 1996

By R. Hurman Eric

Within the Ag-Pb-S ternary system, the boundaries of the immiscibility region together with the tie-line distributions were re-established at 925°C by the equilibrium-quenching technique where samples were kept in evacuated and sealed silica capsules. Activities of Pb were measured by the dew-point method along the Ag-Pb binary at 925°C, 1100° and l200°C, positive deviations were observed and the results were modeled by the Krupkowski formalism. Activities of Ag, Pb, and S, along the ternary miscibility gap were calculated at 925°C by utilizing the boundaries binary thermodynamics, phase equilibria and tie-lines. Activities of PbS within the pseudobinary Ag2S-PbS mattes were also measured by the dew-point technique and the results were again modeled by the Krupkowski formation where negative deviations were observed.

Jan 1, 2003

By R. Hurman Eric

Within the Ag-Pb-S ternary system, the boundaries of the immiscibility region together with the tie-line distributions were re-established at 925°C by the equilibrium-quenching technique where samples were kept in evacuated and sealed silica capsules. Activities of Pb were measured by the dew-point method along the Ag-Pb binary at 925°C, 1100° and 1200°C. positive deviations were observed and the results were modeled by the Krupkowski formalism. Activities of Ag, Pb, and S, along the ternary miscibility gap were calculated at 925°C by utilizing the boundaries binary thermodynamics, phase equilibria and tie-lines. Activities of PbS within the pseudobinary Ag2S-PbS mattes were also measured by the dew-point technique and the results were again modeled by the Krupkowski formation Where negative deviations were observed.

Jan 1, 2003

By A. Mezei

A process has been developed to recover cobalt, gold and bismuth from the NICO deposit in Canada. The process consists of a bulk rougher flotation followed by an optional separation by flotation to produce a bismuth concentrate and a cobalt concentrate, grading on average 12.8 % Bi and 1.8% Co, respectively. Cobalt is leached by pressure oxidation at 97% efficiency, producing a pregnant solution suitable for further processing. Before optimization, about 38% of the bismuth is recovered in the selective concentrate, wherefrom it is recovered by ferric chloride leaching followed by cementation, at overall efficiencies exceeding 98%. The gold is recovered from the cobalt and bismuth leach residues by cyanidation, at 95% efficiency. Previous work described the results of the leaching of the concentrates, recovery of gold (Part I) and the recovery of bismuth (Part 11). This work describes the results of the cobalt recovery testwork and the resulting conceptual flowsheet. The sulfur dioxide-oxygen system was the most efficient for the oxidationlprecipitation of iron and arsenic from cobalt bearing pregnant leach solutions, producing purified solutions assaying <1 mg/L As and <8 mg/L Fe. The efficiency of cobalt solvent extraction (from the resulting purified PLS containing about 1 g/L Co) ranged from 9 1 to 98%; the co-extractions ranged from 88 to 100% for copper, from 28 to 33% for magnesium, from 6 to 7% for calcium and from 96 to 98% for zinc. Sulphide precipitation processes (using either sulfur dioxidelelemental sulfur or sodium sulfide) produced residual copper concentrations in the cobalt strip solution ranging from 0.1 to 2 mg/L Cu. About 90% of the calcium and magnesium were separated by scrubbing the organic with cobalt sulfate, producing residual concentrations of 12 mg/L Ca and from 180 to 330 mg/L Mg in typical feed solutions directed to cobalt carbonate precipitation tests. Cobalt carbonate precipitation efficiencies ranged from 75 to 78% when calcium and magnesium co- precipitations were restricted from 8 to 17% and 0.3 to 0.4%, respectively. The limits required by most stringent specifications on commercial grade cobalt carbonate products were met or exceeded.

Jan 1, 2002

By R. Hurman Eric

The flow of molten slag and matte and the estimation of the mass of settled matte in electric furnaces is discussed and the action of the electric furnace as a settler is considered. Particle size of the concentrate and its grade are major contributors to settler dimensions. Discussion on the production capacity of the electric furnace with reference to operating current, power input, furnace dimensions such as width and length and electrode diameter are given. These discussions are based on considerations derived mainly from experimentally determined properties of the slag such as its resistivity, viscosity and liquidus temperature. Extension of the design and operating considerations to circular furnace symmetry is also discussed.

Jan 1, 1995

By Peter R. Sanford

Cyanides are present as a dilute constituent of streams from a variety of metallurgical and mineral-processing operations. In addition, a cyanide concentration in excess of approximately 100ppb is toxic to aquatic life, and consequently these operations require a waste-treatment process to reduce the already dilute cyanide species by several orders of magnitude. Furthermore, the waste streams may have flowrates in excess of a million gallons per day. The paper reports on research conducted with a laboratory?scale electrochemical porous (graphite felt) electrode (anode) flow-reactor, which was conducted in conjunction with a computer-aided simulation of a mathematical model describing the intrinsic rate-phenomena associate with the electrode processes. The laboratory-scale cell, of rectilinear geometry, was found to be capable of reducing a feed-stream anolyte (KCN-KOH and supporting electrolyte of a single salt ? K2SO4) with a cyanide concentration of 10ppm, to less than 100ppb, at current efficiencies in the neighborhood of 50%. The computer simulation of the cell performance based on the mathematical model (and constraints imposed for tractability) was found to provide only for qualitative agreement.

Jan 1, 1998

By A. M. Strachan

The application of submerged electric arc furnace smelting techniques to tin concentrates at the Capper Pass tin smelter in England is discussed. Some experimental data from earlier small scale 50 KVA electric smelting testwork on various low and medium grade tin concentrates is presented. Design considerations for the construction of a 3 MVA electric furnace to treat tin concentrates from the East Kemptville mine in Canada are considered, together with necessary precautions peculiar to the construction of a high grade smelter in close proximity to an existing low grade, complex non-ferrous metal smelting operation<. Slag composition modifications to optimise operational smelting conditions for various concentrates treated are discussed, together with refractory selection. The effect of concentrate impurity levels on the permissible degree of recycle to produce a satisfactory metal product is highlighted.

Jan 1, 1990

By A. W. Worcester

The plant is designed to produce 60,000+ tons of refined lead per year from a nominal feed consisting of 110,000 tons of SLI and industrial batteries, and 10,000 tons of lead contained in drosses and scrap. The plant will also produce as by-products polypropylene chips and detergent grade sodium sulfate, using the Engitec Impianti CX Technology. The battery separation circuit will consist of a battery breaking hammermill and a vibrating screen with water sprays to separate the battery paste from the grid metal and other battery components. The battery components, consisting of ebonite, and separator materials, will be separated&apos; from the grid metal and classified with the use of hydrodynamic water separators. The battery paste will be treated with sodium carbonate to produce a lead carbonate paste for smelting in a reverberatory furnace. The slag from the reverberatory furnace will be campaigned through a traditional primary blast furnace to produce hard lead. The sodium sulfate liquor from the lead carbonate filtration step will be crystallized to produce anhydrous sodium sulfate. The metallic grid metal will be treated through a small rotary smelter of the Engitec design to produce a hard antimonial lead. The plant&apos;s scheduled to be commissioned 12 months after receipt of all of the Federal and state permits. The plant will be integrated into the Buick Primary Lead Smelter, located in the center of Missouri&apos;s New Lead Belt, at Boss, Missouri. This will allow The Doe Run company to fully utilize all of its existing assets.

Jan 1, 1990

By B. Manoj

Coal is a mineral and is extensively used as a solid fuel in developing nationsand hasa sizeable share inthe global fossil fuel reserve. Utilization of this resource generates excess spoil and large volume of low grade waste to the environment. In recent years there have been serious research on enhancing its value and exploring the utility of this carbonaceous material to novel carbon materials.

Mar 1, 2018

By Willy Persson

A common feature of the kinds and amounts of impurities present most pyrometallurgical, processes is injection of oxygen to, remove various in the feed. The degree of success of a specific process step relies critically on control of the instantaneous oxygen potential/oxidation stage, throughout the step as well as upon termination of the step. This will, for instance, determine the distribution of impurities between metal and slag. As long as the operation is perturbation free -detailed analysis of all additions and application of advanced models often yield satisfactory control means However, a pyrometallurgical process is seldom free from disturbances, which reduces the accuracy of the static models and leads to inconsistencies in scheduled route might be uncontrollable changes in quality and quantity of feed, operator interventions and shift changes, timing of cranes, lining wear and accretions etc. The implementation of dynamic, control to correct for disturbances and, more generally for process optimization, requires continuous on-line information on, the actual status of the process. The implementation of sensors for continuous process monitoring, e.g., as regards the instantaneously prevailing oxygen potential or oxidation stage, has been hampered by the highly aggressive environment in smelters; This is. where remote-sensing techniques based on optics and spectroscopy, have proven to form invaluable, tools towards the realization of dynamic production control. Since about 15 years Semtch has developed and industrialized a remote-sensing technology, based on ,optics and spectroscopy, for continuous on-line process monitoring and production control of various pyrometallurgical processes. The presentation will discuss applicability aspects with examples and experiences from installations and tests in ferrous and non-ferrous industry. Keywords: Applied spectroscopy, Metallurgy, Process monitoring, Production. Control

Jan 1, 2003

By Xun Hu, Jian Pan, Hongbin Yu, Deqing Zhu, Yanhong Luo

Lump ores are one kind of important burdens for blast furnace (BF), their metallurgical properties have significant influence on BF performance. In this paper, the relationships between the mineralogy of five natural lump ores and the metallurgical performance have been studied. The mineralogy study includes mineral compositions, microstructure and porosity, and the metallurgical performance covers reducibility index (RI), low-temperature reduction degradation index (RDI) and decrepitation index (DI). The results show that the complex lump containing hematite, and goethite has better overall metallurgical performance. For single lump, the RI of goetihte ores is higher, the RDI and the DI is strongly influenced by porosity. The hematite and magnetite ores have good anti-decrepitation and anti-RDI, but generally the RI is lower due to lower porosity, and the RI is related to the grain size, the smaller grain size is, the better reduction will be.

Jan 1, 2015

By T. C. -M. Cheng

Iron removal and disposal in zinc plants has imposed a major environmental challenge to the industry. Among the existing options of precipitating iron as jarosite, goethite, and hematite, the Hematite Process seems to be the best candidate for the future development of a waste-free technology, because of its potential of producing saleable iron oxide residues for feed in iron-steel making industry. Unfortunately, under the current practice of the Hematite Process, it is not possible to produce iron residues clean enough to meet the specifications of the said industry. In this paper, the practice of industrial hematite precipitation and the relevant technical literature are reviewed with the objective to identify the critical processing parameters which are responsible for the contamination of hematite, particularly with sulfur and zinc. The analysis is conducted from a crystallization theory standpoint with emphasis given to the role of supersaturation with respect to the cleanliness of hematite precipitates.

Jan 1, 1997

By Mark H. Hashiguchi

Examination of tensile bar surfaces shortly after destructive testing was conducted to search for clues that would aid in optimization of mechanical properties, especially tensile strength, yield strength and elongation to fracture. Cu-Ni-Si-Cr alloy bars in the as-cast, forged, rolled and extruded conditions were examined. Low ductility bars (<4% Elongation) showed dramatically different features than the fracture surfaces of high strength - high ductility bars (7 to 10% Elongation). Analysis of the fracture surfaces at 15X to 2000X and use of Energy-Dispersive X-Ray Spectroscopy (EDS) identified Ni-Si and Ni-Si-Cr precipitates of varying sizes and morphologies. Thermo-mechanical processing techniques to control the size and distribution of these precipitates show promise in improving the properties and performance of this alloy system and appear to correlate with improvements in the fracture surface morphology.

Jan 1, 2008

By M. Fujikawa, S. Goto, M. Nishikawa

"The semi-pilot scale plant for injection smelting of zinc calcine was operated under the committee of Joint Research Organization of Injection Metallurgy. The capacity of the plant is 10 ton metallic zinc per day. The plant was designed by the resul ts of basic and bench scale tests of the capacity of 1 ton metallic zinc per day which was published at ""Zinc '85"". The equipments of the plants, operational conditions, results of the operation such as recovery of zinc in injection furnace and condenser, combustion rate of powdered coke and consumption of energy in this process are presented in this paper. The results of the study of the feasibility of the commercial plant of 100,000 ton zinc per year by the injection smelting are also discussed in the paper. IntroductionThe research committee of new smelting process of zinc by injection was established in 1981 under the finantial support of Mining Promoting Foundation of Japan. Six zinc producing companies joined in this organization. The price of zinc was very low at that time and the energy cost, especially, cost of electric power in Japan was extremely high. Invention of a new economical process for zinc extraction had been stronglydesired. The author proposed a injection smelting of zinc as a economical process in energy saving after a calculation of thermodynamical equilibrium and heat balance(1 )(2).The research committee has been studying the injection process since 1981. The small basic experiment by using a crucible furnace was carried out from October 1981 to March 1983 and the reaction of reduction of calcine by injection smelting was ascertained (2). Vaporizatipon of zinc and behaviours of impurities were examined. After the basic experiment, the bench scale test with the production capacity of zinc of 1 ton per day was carried on from November 1983 to October 1984.The bench scale tests were carried out to obtain the proper design of feeding devices of calcines and coke into a furnace and also to obtain fundamental data for enlargement of this smelting process(3,4). The recovery of metallic zinc in this small equipments was about 50% and main loss of zinc was formation of dross in the condenser."

Jan 1, 1988

By Gabriel Bartholazzi Lugão de Carvalho, Sergio Neves Monteiro, Fabio Da Costa Garcia Filho

The thermochemical treatment of Pulsed Plasma Nitriding is employed as an alternative to improve the surface properties of metals, such as: increase surface hardness, improve wear resistance, extend fatigue life and also create a barrier to the diffusion of hydrogen into the steel to reduce the susceptibility to hydrogen embrittlement. In this study, the effect of such treatment on ASTM A36 steel is analyzed through two different nitriding conditions: 5 h and 660 Pa for the first condition and 15 h and 720 Pa for the second one. In both cases, the temperature was held at 300 °C. Thus, in order to verify the results, Vickers hardness analysis and metallographic observation were carried out under an optical microscope. Only the second condition was able to achieve what was proposed, the formation of a uniform nitriding layer and an expressive increase of hardening on the surface.

Mar 1, 2018

By B. L. Chulu

In the carbothermic reduction of lead sulfate to produce lead, the inclusion of soda ash (Na,CO,) in the charge provides for the control of sulfur dioxide in the effluent gas. An important mechanism in the process appears to be the carbothermic reduction of the sodium carbonate whereby sodium gas and carbon monoxide are produced. These intermediates then participate in the reduction of the lead sulfate to produce lead metal and stable sulfur species in the molten slag phase. In addition, there is some evidence that the presence of lead metal in the charge may also serve to increase the lead recovery in the process. These aspects were investigated by conducting laboratory-scale smelting tests with small charges (;3g), at 1173°K(9000C). Recovery did not exceed 74w% and the role of incipient lead metal in the charge could not be clearly assessed.

Jan 1, 1993

By V. Reiter, K. Reinharter, C. Wenzl, D. Gregurek, A. Spanring

The refractory linings in lead furnaces are exposed to several stresses rather complex in their interaction. In the present study the magnesia-chromite brick out of a lead recycling furnace suffered from a high chemical attack by the process slag. The high CaO, BaO and sulfur bearing silicate slag, as well as a high NaO2 supply from soda resulted both in a deep-reaching infiltration of the brick microstructure and a severe corrosion of the brick components. Both the sintered magnesia and chromite were attacked chemically. The FactSage calculations showed the formation of high amounts of liquid phase in the infiltrated microstructure. Further phenomena affecting the refractory performance such as iron oxide attack, redox effects, and boron attack are also discussed in the paper. The obtained information and insights serve as a basis for improving refractory materials (i.e., choice of refractories for individual process and new developments) and consequently furnace operations.

Mar 1, 2017

By C. Takano

The integrated iron and steelmaking industry generates large amounts and many types of solid dusts and sludge, at different phases of the production. Within these are: sludge of the Blast Furnace; coke fines; fine and coarse fractions from oxygen converters; sludge from water treatment at rolling mill unit; and others. In this paper the above dusts and sludge were physically and chemically characterized. The obtained results allowed defining self-reducing pellets using these materials. The high temperature behavior of the pellets were evaluated. Good results, with no decrepitation and swelling, and high yield of reduction, show that it is feasible to recycle them, as self-reducing pellets, in oxygen steelmaking converter.

Jan 1, 2001