Search Documents

This symposium is dedicated to the lifetime achievements of Professor H.Y. Sohn. It covers the scientific fields, processing routes and investigation techniques in which Prof. Sohn has worked during his career and is based in the equally important three topical areas: Principles, Technologies, and Industrial practice. Professor Sohn was General Chair of the very first TMS Fall Extraction and Processing Symposium in 1983 in San Francisco which led to the Annual such symposia as this International symposium. Furthermore, the theme of that symposium was sulfide smelting, which is also included in this symposium. [ ] Professor Sohn was born in a beautiful dynastic capital Kaesung, Korea on August 21, 1941. He received his B.S. degree in 1962 from Seoul National University, M.Sc. in 1966 from the University of New Brunswick, Fredericton, N.B., Canada, and his Ph.D. degree in 1970 from theUniversity of California at Berkeley all in Chemical Engineering. After working as a Research Associate at the State University of New York at Buffalo and as a Research Engineer at Du Pont?s Engineering Technology Laboratory, Dr. Sohn joined the Department of Metallurgical Engineering at the University of Utah in 1974 and currently holds the ranks of Professor of Metallurgical Engineering and Adjunct Professor of Chemical Engineering.

Jan 1, 2006

This symposium is dedicated to the lifetime achievements of Professor H.Y. Sohn. It covers the scientific fields, processing routes and investigation techniques in which Prof. Sohn has worked during his career and is based in the equally important three topical areas: Principles, Technologies, and Industrial practice. Professor Sohn was General Chair of the very first TMS Fall Extraction and Processing Symposium in 1983 in San Francisco which led to the Annual such symposia as this International symposium. Furthermore, the theme of that symposium was sulfide smelting, which is also included in this symposium. [ ] Professor Sohn was born in a beautiful dynastic capital Kaesung, Korea on August 21, 1941. He received his B.S. degree in 1962 from Seoul National University, M.Sc. in 1966 from the University of New Brunswick, Fredericton, N.B., Canada, and his Ph.D. degree in 1970 from theUniversity of California at Berkeley all in Chemical Engineering. After working as a Research Associate at the State University of New York at Buffalo and as a Research Engineer at Du Pont?s Engineering Technology Laboratory, Dr. Sohn joined the Department of Metallurgical Engineering at the University of Utah in 1974 and currently holds the ranks of Professor of Metallurgical Engineering and Adjunct Professor of Chemical Engineering.

Jan 1, 2006

By Vânia L. L. Andrade

Igarapé Bahia Mine is located in Carajás area, northern Brazil. Currently Companhia Vale do Rio Doce operates there a CIP / heap leaching plant treating an oxide gold ore containing about 4 g Au /t and 0,2% Cu, which produces 11 t of gold per year. Recent geological survey has identified a signifcant copper-gold reserve underneath the oxide gold ore. The processing aspects of this copper-gold sulphide ore are described in this paper. It includes ore characterization studies, grinding and flotation tests, orebody variability assessment, flowsheet selection and preliminary economical evaluation Emphasis is given to studies aimed at depressing fluorine bearing minerals to achieve a clean and marketable flotation concentrate.

Jan 1, 1999

By R. Padilla

Enargite (Cu3AsS4) occurs normally associated with copper sulfides, mainly chalcopyrite. When the enargite content in chalcopyrite concentrates is high, direct smelting of the concentrate presents problems related to environmental pollution and contamination of the final metallic copper. Leaching processes are viable alternatives to treat copper concentrates with high content of enargite. Consequently, in this paper, the pressure leaching of enargite in sulfuric acid-oxygen system is discussed. The leaching rate was studied in the range 160 to 220 °C and partial pressures of oxygen of 74 to 200 psi. The enargite dissolution increased substantially with temperature increase. Complete dissolution of enargite was obtained at 220°C, and 100 psi of oxygen pressure in 90 min. The shrinking core model controlled by surface reaction was used to analyze the kinetics of enargite dissolution. Activation energy of 70 kJ/mol was obtained for the temperature range 160 to 220 oC.

Jan 1, 2008

This symposium is dedicated to the lifetime achievements of Professor H.Y. Sohn. It covers the scientific fields, processing routes and investigation techniques in which Prof. Sohn has worked during his career and is based in the equally important three topical areas: Principles, Technologies, and Industrial practice. Professor Sohn was General Chair of the very first TMS Fall Extraction and Processing Symposium in 1983 in San Francisco which led to the Annual such symposia as this International symposium. Furthermore, the theme of that symposium was sulfide smelting, which is also included in this symposium. [ ] Professor Sohn was born in a beautiful dynastic capital Kaesung, Korea on August 21, 1941. He received his B.S. degree in 1962 from Seoul National University, M.Sc. in 1966 from the University of New Brunswick, Fredericton, N.B., Canada, and his Ph.D. degree in 1970 from theUniversity of California at Berkeley all in Chemical Engineering. After working as a Research Associate at the State University of New York at Buffalo and as a Research Engineer at Du Pont?s Engineering Technology Laboratory, Dr. Sohn joined the Department of Metallurgical Engineering at the University of Utah in 1974 and currently holds the ranks of Professor of Metallurgical Engineering and Adjunct Professor of Chemical Engineering.

Jan 1, 2006

By Roberto Javier Santiago

The main properties of Calcium Carbide seem to be the grain size and the CaC2 content. This paper tries to describe the Calcium Carbide used in the South-American steel plants and how and where it is added.

Jan 1, 2006

By Yang Hong-ying, Yu Juan

Electrochemical behavior of natural chalcopyrite in electrolyte solution at pH value of 6.97 was studied by cyclic voltammetry, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy. The results showed that the electrochemical processes occurred on electrode surface were controlled mainly by the growth of sulfur species at lower applied potentials (<0.35Vvs.SHE), and the oxidative dissolution of sulfur species and the hydroxylation of iron at higher applied potential (>0.45V). The EIS spectra of oxide product layers could be illustrated by the equivalent circuit of Re(QdlRct(QfRf)), and the degree of hydrophilicity for chalcopyrite was higher when the value of charge transfer resistance Rct. was greater. The optimum potential range for the floatation of chalcopyrite in collectorless solution at pH value of 6.97 was between OCP (0.165V) and 0.35V.`

Jan 1, 2015

By Petr Sulovsky, Pavel Leber, Jaroslava Ledererova, Miroslav Svoboda

"The properties of raw materials used for the production of building materials play an essential role in their choice. Industrial waste materials can in some cases improve the performance of new building materials, when compared with classical raw materials. The addition of waste can however negatively impact some of the building material´s characteristics, influencing its stability, service time, durability, and can introduce undesirable variation of certain characteristics over time. It is necessary that each secondary raw material intended for such use be thoroughly investigated in terms of its chemical, physical, and mechanical properties, with special attention paid to the risk components and risk parameters. It is necessary to make many- sided technological tests in relation to the required characteristics of the resulting materials for each chosen application. Moreover, the limit values for the critical (risk) parameters, which the given secondary raw material must satisfy to be used in a specific technology, need to be defined. Introduction The risk components in the industrial waste materials to be used in the production of building materials fall into two groups: - components that pose a risk of development (instant or delayed) of a process deleterious to the utility properties and durability of the resulting materials. Such processes include volume change (expansion as well as shrinkage), alkali-silica reaction, delayed ettringite formation, thaumassite attack, aggressive carbonation, etc. - elements or components that can, if released from the waste-containing building material, pollute the environment. They involve the so called potentially hazardous elements as well as compounds like fenols, PCB, PAHs etc. From the viewpoint of the presence of both groups of risk components, the wastes can be classified as: • environmentally inert waste materials. They are produced in the largest volumes and do not pose a threat to human health. Their physical and/or chemical characteristics fail to satisfy all requirements for utilization in ordinary production. The aim of technology design is to work them into the building products with suitable utility properties. • easier workable waste materials containing toxic components are produced in large volumes. In spite of the content of toxic components, their physical and chemical properties make them suitable for ordinary production, provided that the harmful substances are immobilized by the chosen technology."

Jan 1, 2008

By G. Ramadorai

"This paper addresses processing options for recovering gold from carbonaceous sulfidic gold ores. These include, but not limited, to the following methods: (1) Hypochlorite pretreatment followed by cyanidization; (2) Chemical blanking agents pre-treatment followed by cyanidization; (3) Non-cyanide heap leaching techniques; (4) biological pre-treatment followed by cyanidization; (5) biological pre-treatment followed by non cyanide heap leaching. Issues of costs, economics, recoveries, testing methods, state of advancement etc., will be discussed in the paper.ABSTRACT ONLY"

Jan 1, 1997

By V. Panchanathan

The rapidly solidified Nd-Fe-B powders form the entire basis of the bonded magnet industry At present the rapid solidification is carried out exclusively by melt spinning, producing flake like particles having highly stable and magnetically hard microstructure These particles are comminuted into powder before being processed into bonded magnets These powders are magnetically isotropic having coercivities from 4 to 16 kOe The other type of powder recently introduced for bonded magnets is the anisotropic powder made by the hydrogen decomposition desorption recombination (HDDR) process. The characteristics and application of these isotropic and anisotropic powders are discussed.

Jan 1, 1997

By John R. Hugens

Modifications in the ALSCAN method of measuring hydrogen dissolved in liquid aluminum have made it possible to monitor the level of hydrogen dissolved in liquid copper. Measurements from the tundish show a correlation with eddy current readings from the continuously cast and rolled copper rod from the continuous casting and rolling system at Amarillo. The measurements also indicate that the copper in the tundish is supersaturated with hydrogen.

Jan 1, 1994

By Ying Li, Xuling Chen, Xiaohui Fan

"In the sintering process, the behavior and performance of iron ores is extremely complex. Different minerals have different sintering properties. In order to use iron ores rationally and effectively, multilevel fuzzy evaluation method is used to establish the comprehensive evaluation model of iron ores. Because of the relative independent characters of iron ores in sintering process, the characters can be divided into physical and chemical properties, granulation performance, and sintering properties, are divided, and together with iron ores prices as the first level index for judging, which are used as the second level index for judging. Using the analytic hierarchy process (AHP) to determine the weight of each index, which is used as the second level index. The relative membership matrix is determined by triangular membership function, the comprehensive evaluation model is established.IntroductionIn China, sintering is the main method for iron ores agglomeration. Sinter accounts for more than 80% of the blast furnace. Sinter production in the iron and steel enterprises in China plays an important role[l-2]. As the main raw material of iron ores sintering, the objectivity and integration of iron ores evaluation is essential. The iron ores evaluation methods include of metric ton price evaluation method, iron grade of a single iron ores sintering, acid-base balance method, composition assessment method and other methods which are based on the chemical composition and physical properties of iron ores to measure the quality of iron ores[3]. The high-temperature mineralization is an important process in sintering process, which affects the structure and mineral composition of the sinter, and has a close relationship with the quality of the sinter[ 4]. Therefore, in consideration of the physical and chemical properties, granulation properties, mineralization performance and sintering properties, the iron ores are evaluated by multi-level fuzzy comprehensive evaluation. The multi-level fuzzy comprehensive evaluation method makes a comprehensive evaluation, applying fuzzy transform principle and maximum membership degree principle, considering a number of factors related to the things which are evaluated. The method has lower requirements for the amount of data, and which integrates qualitative with quantitative judgment. It has a unique advantage to make up for the deficiencies of traditional evaluation methods. It also can comprehensively evaluate the iron ores in a relatively short period, reduce a lot of experiments, improve efficiency and guide the sinter production[5-6]."

Jan 1, 2013

By A. Warczok

The heat transfer coefficient between liquid slags and solid surfaces is important for the design and operation of metallurgical reactors. An experimental technique developed for the purpose of measuring the heat transfer coefficient between liquid slags and solid metals is described. During the initial heating up of a Ni cylinder upon immersion in a liquid slag, a layer of frozen slag initially forms, then melts. The heat transfer coefficient measured during the initial rapid heat-up of the Ni cylinder, is approximately twice as high as the heat transfer coefficient measured during the final heat-up of the Ni cylinder subsequent of the liquidus temperature of the slag. The technique was tested in various melts i) NaNO3, ii) NaCl, iii) Na3AlF6 and iv) 2FeO*SiO2, giving consistent results. It was found that the heat transfer coefficient increases with increasing bath superheat and stirring. The heat transfer coefficient during the heating up following complete remelting of the frozen slag, is related to the slag superheat(AT) and the specific stirring energy(W) per kg of slag(E) as follows.

Jan 1, 1993

By R. Gampala

The consolidation of mom matrix composite monotapes occurs by the plastic (time independant) and creep deformation of monotape asperities. Past models of the process used seperate micromechanical analyses of the contact deformation by (rate independent) plasticity and power law creep (i.e steady state creep). These models are now used to simulate consolidation and to optimize/control consolidation process cycles so that the composite&apos;s microstructure is "steered" to, a user defined goal state. However, the models do not incorporate the sometimes dominant transient creep process and the instantaneous response of the plasticity mechanism causes finite discontinuities in the microstructure state vector field and therefore eliminates the possibility of using the powerful array of trajectory optimization schemes that all require continuous vector field for optimization and control. To overcome this problem, a inified creep/plasticity constitutive model that results in a continuous state vector field is used to rederive the contact deformation response during monotape consolidation. The contact blunting of a laterally constrained hemispherical asperity is first analyzed and its response represented by two coefficients; one relating the contact area to the blunting strain (C), the second, the mean contact pressure to the blunting rate (F).The C and F coefficients for this unified blunting problem are then obtained by finite element analysis, and detailed results presented for two composite matri-ces of topical interest (Ti-24A1-11Nb and Ti-6Al-4V).

Jan 1, 1996

By Jun Li

Several metal sulfides were examined in-situ by Raman spectroscopy before and after anodic oxidation. Results obtained for chalcocite, chalcopyrite, covellite, galena, pyrrhotite and pyrite electrodes are presented. Under appropriate conditions, sulfur was detected after a potential was applied to the mineral electrodes for a threshold period of time. For all the minerals, application of a negative potential on the oxidized mineral reduced the surface product and the sulfur peaks disappeared from the observed spectra. For those minerals containing sulfur as S< in the crystal lattice, polysulfides were identified as oxidation intennediates.

Jan 1, 1993

By Adolfo Pillihuaman, Alberto Nogueira, Cyro Takano, Marcelo Mourão

The organic household waste has a growing disposal problem, requiring costly disposal systems. It is necessary to find new applications for these materials; one could be the steelmaking raw material production. In this paper is studied the development of self-reducing pellets from the organic waste pyrolysis, where is generated carbon and condensable and non-condensable volatiles. Non-condensable volatiles were burned and condensable volatiles were recovered. The resulting tar was mixed with iron ore, coal powder and flux (CaO), to then be pelletized together. Compression, falls and tumbler tests were conducted to characterize the pellets before and after heat treatment and reduction processes. The reduction curve and their physical and morphological characterization were measured. The results were as was expected, the fluidized coal create sufficient adhesion that pellets earned resistance with an equivalent resistance of common pellets, showing a good feasibility of this process.

Jan 1, 2015

By J. Vander Linden, R. De Ketelaere, M. Verhaege

In this paper, results are presented concerning the search to implement Supported Liquid Membrane (SLM) technology for the recovery of copper from electroplating effluents. Acid copper electroplating rinse solutions or effluents resulting from the post-treatment of, for example, cyanide-containing copper electroplating baths all contain copper (2+) in the lower concentration levels. A thorough study of the influence of the individual parameters and of their combined impact on mass transfer in small scale laboratory SLM modules has been performed, enabling to set forward the appropriate operating conditions for a pilot plant installation. The pilot plant, containing two SLM modules. of 18 m2 of surface area, has been tested extensively, including short and long term runs, with real process solutions. It was demonstrated that this installation is able to treat 40 l/h of acid copper sulphate rinse solutions· containing 500 ppm of copper. The final copper concentration in the effluent can be reduced to a few ppm while copper metal is recovered by electrolysis of the concentrate. This technology is also applicable to the treatment of solutions with low copper content of origins other than plating shops, such as tailings from copper plants or mine waters.

Jan 1, 2000

By Chu Bo-Yi

"This paper contains a comparison of creep-feed and shallow-cut grinding on ceramics with both neat oil and water-based grinding fluids. When a water-based grinding fluid was used in creep-feed grinding on ceramics the vertical forces and specific energies increased markedly fast with result that the wheel surface was damaged seriously. Creep-feed grinding on ceramics with neat oil not only produced much lower grinding forces and specific energies but also resulted in the wheel remaining in good condition and minimizing damage to the ground surface. This finding may lead to a deeper understanding of the behaviors of grinding fluids in grinding processes both on ceramics and metal as well.1. IntroductionAs advanced ceramics are obtaining more and more applications in the technical area, some machining processes are needed after the sintering to reach the accuracy and finish required by components. Because of higher hardness and brittle behaviors of modem ceramic many researches have been done in order to improve grinding efficiency and surface quality.In the grinding metals the concept of creep-feed grinding has been developed in industry as a real alternative to the normal method of shallow-cut grinding. In addition to the general economic advantages, dimensional accuracy and surface integrity are invariable improved using the creep-feed grinding technique.In grinding ceramics former studies have done many works on both creep-feed and shallow-cut grinding on ceramics with water-based grinding fluids since the water-based were thought to be better coolants than neat oil in most tests of grinding metals[l]. It was suggested that the specific grinding energies of ceramics are markedly higher in creep-feed grinding. The grinding force increases vary rapidly with time in the creep-feed case. In other words, so-called speed stroke grinding with high workpiece speed is considered more suitable for improving the grinding efficiency [2][3]."

Jan 1, 1998

By Juliana G. Gutierrez-Paredes, Gabriel Plascencia-Barrera, Fidel Reyes-Carmona

In Mexico, many tonnes of nickel from waste petrochemical catalysts are dumped every year. In order to recover all that nickel, a hydrometallurgical reactor was designed. This design was performed in a systematical fashion, which included the chemistry of the system under study, both a kinetic and mass transfer study, and finally the use of the RID function, to optimize the reactor size. It was found that the NiO leaching with sulfuric acid is well represented by a first order reaction. The mass transfer results are in good agreement with the experimental results, obtaining over 95% nickel extraction in both cases. A marketing study was also completed that determined that it is possible to make a good profit by processing this residue provided the capital cost was low.

Jan 1, 2000

By A. Elizabet Serna

The weak acid is a by product obtained in a pre-treatment of gases from a copper smelter prior to sulfuric acid manufacture and the main components of this weak acid are: sulfuric acid. copper, arsenic. antimony, bismuth and iron. Usually, this effluent is neutralized with lime and the solid residues are stored in a landfill as a hazardous waste. This work was directed at determining the optimal conditions to recover copper from weak acid using a cementation process before the neutralization of the effluent. The variables investigated are: Effluent temperature, iron scrap amount and acid concentration versus reaction time. The results of these experiments show that the cementation process of copper and the co-cementation of impurities such as arsenic, antimony and bismuth were in accord with the theory of the electrode potentials.

Jan 1, 1996