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By A. E. M. Warner

At the Copper Cliff Smelter, Inco Limited has extensive experience in converting primary smelting mattes over a broad range of nickel/copper ratios and compositions. In the past 35 years, technology developments at Inco have reduced the number of Peirce-Smith converters in Nickel/ Bulk (nickel-copper matte) service from 13 to the current 5. This paper will discuss: ? The performance and life of ?stretch? 13.7m shells versus conventional 10.7m converters. ? Process control and information system development from the early 1980?s to view converter aisle status on a continuous basis to the recent central control of the stretch shells. ? Nitrogen cooling of finishing matte from plant testing to implementation in the early 1990?s to replace the dedicated cooling converters. ? The impact on converting of changing the smelter flowsheet in the early 1990?s. ? A current program to develop a converting strategy for the future to address environmental issues and profitability.

Jan 1, 2005

By A. J. Rigby

Refractory linings in converters or anode furnaces used to over-oxidize the blister copper will suffer rapid deterioration, due to prolonged contact with copper oxide-rich slag. Nitrogen stirring with COP KIN porous plugs and use of SEMTECH OPC in converters and anode refining vessels can considerably reduce both refractory wear and processing times. In addition, careful control of the vessel atmosphere and the use of real-time optical process control minimize both slag volume and contact time with the vessel refractory.

Jan 1, 2005

By Hong Yong Sohn

Keywords: Barium sulfate, Barium sulfide, Environment, Kinetics, Pollutants, Sulfur dioxide conversion, Thermodynamics Nonferrous smelters and coal gasification processes generate sulfur dioxide streams, most of which are treated to produce sulfuric acid with the accompanying problems of market shortage and transportation difficulties. While the conversion of sulfur dioxide to elemental sulfur has many environmental advantages, no processes exist that are environmentally acceptable and economically viable. A method for converting sulfur dioxide to elemental sulfur by a cyclic process involving calcium or barium sulfide and calcium or barium sulfate without generating solid wastes has been developed. In this process, the sulfate, as the starting raw material, is reduced by a suitable reducing agent such as hydrogen to produce the sulfide, which is used to reduce sulfur dioxide producing elemental sulfur vapor and regenerating the sulfate. The latter is then reduced to reproduce the sulfide. This paper describes work on the BaS/BaSO4 system. Thermodynamic analysis and experimental results indicated that the BaS-SO2 reaction produces mainly sulfur vapor and solid barium sulfate and that the gaseous product from the BaSO4-H2 reaction is mainly water vapor. The rates of the two reactions are reasonably rapid in the temperature range 700-1050°C.

Jan 1, 2005

By G. H. Khoe

Neutralisation of acid uranium mill tailings with lime or other alkaline materials is usually practised to reduce the dissolved concentration of heavy metals and radio nuclides. Computer modelling of this process was carried out using the geochemical equilibrium code MINTEQA2. Computed dissolved metal and sulfate concentrations were compared with laboratory-based experimental data. It was found necessary to include the modelling of adsorption of trace metals (such as uranium and lead) by the precipitated ferric hydroxide in order to obtain acceptable concentrations in the neutralised liquors. There were limitations of the modelling exercise due to important aspects which were not addressed or properly accounted for such as chemical reaction kinetics and the effect of high ionic strength. These are discussed in the paper.

Jan 1, 1991

By M. Hochenhofer

Keywords: desulfurization, mathematical model, slag reaction To produce ferroalloys like ferro-nickel for alloying purposes in a quality that meets the requirements of today?s steel industry, refining processes like desulfurization and dephosphorization are indispensable. The performance of desulfurization-treatment by slag reaction depends on various parameters, such as: sulfide capacity and viscosity of the slag, sulfur distribution between metal and slag, activity of sulfur in melt and movement of melt. Within this work, the combined influences of these parameters on the desulfurization of a ferro-nickel alloy were examined. As a basis for this examination, a mathematical model, based on data from plant trials, was created. This model demonstrates the relationship between desulfurization rate and initial values of the above mentioned parameters. With this model the relevant parameters were evaluated and assessed concerning their influence on desulfurization.

Jan 1, 2005

By Wang Shulan

The synthesis process of BaTiO3 from TiO2 and BaCO3 in the molten NaOH-KOH at 350oC was studied by the A.C impedance technique. The A.C. impedance of molten NaOH-KOH (xNaOH = 0.36) and the variation of the conductivity of the salt with time during the synthesized process were measured. The synthesized reaction of the BaTiO3 and the decomposition reaction of BaCO3 are fast and were finished in 10min. The interaction between TiO2, BaO and BaTiO3 and the molten salt was confirmed by the variation of the conductivity.

Jan 1, 2005

By Regina Maria Pinheiro

This work has for objectives to characterize a waste generated in the form of sludge during the treatment of the effluent of a paper making industry and to evaluate the effect of its incorporation in the amount of 10 wt.% on the properties and microstructure of a clayey body used for brick production. For the characterization of the waste the following techniques were used: X-ray diffraction, X-ray fluorescence, differential thermal analysis and termogravimetric analysis. Incorporated bricks were produced in industrial scale before firing at 750°C in a Modified Caieira type furnace. The physical and mechanical properties evaluated were water absorption and compression strength. The microstructure of the fired ceramic was evaluated by optical microscopy. The environmental evaluation was made by solution test and atmospheric emission by monitoring the release of SO2, NOx and particulate material. The results showed that, in agreement with the characteristics of the waste, its recycling into red ceramic can contribute to decrease the consumption of fuel during the firing stage. The properties of the fired ceramic attend the norms. With respect to the environmental aspect, the incorporation of the waste did not impact the environment.

Jan 1, 2009

By Han-Tao Hu

Keywords: RH refining process, flow of molten steel, two-phase flow, gas holdup, circulation rate, mathematical modeling A three-dimensional mathematical model for the flow of the molten steel in the whole degasser during the RH refining process has been proposed and developed with considering the physical characteristics of the process, particularly the behaviors of gas-liquid two-phase flow in the up-snorkel and the momentum exchange between the two phases. The fluid flow fields and the gas holdups of liquid phases and others respectively in a 90 t RH degasser and its water model unit with a 1/5 linear scale have been computed using this model. The results showed that the flow pattern of molten steel in the whole RH degasser could be well modeled by the model. The liquid can be fully mixed during the refining process except the area close to the free surface of liquid and zone between the two snorkels in the ladle, but there is a boundary layer between the descending liquid stream from the down-snorkel and its surrounding liquid, which is a typical liquid-liquid two phase flow, and the molten steel in the ladle is not in a perfect mixing state. The lifting gas blown is rising mostly near the up-snorkel wall, which is more obvious under the conditions of a practical RH degasser, and the flow pattern of the bubbles and liquid in the up-snorkel is closer to an annular flow. The calculated circulation rates for the model unit at different lifting gas rates are in good agreement with the determined values.

Jan 1, 2005

By Xiangjun Zuo

This paper firstly reviewed the state of the art in the recycling of used Printed Wiring Boards (PWB), and then presented part of the authors study on the combustion of PWB powders with and without the addition of catalyst. During the combustion of PWB powders without catalyst addition, there were two obvious exothermic reactions, one at 300-380oC, the other at 450-500oC. With the addition of catalyst during PWB combustion, there were no obvious exothermic reactions, indicating that dehalogenation reactions are not exothermic: The results showed that NaHCO3 and CaCO3 were very efficient to control the emission of Br2 and C6H6, lowering 80% compared to the case without catalyst, Na2CO3 can slightly control the emission of Br2 gas but not for C6H6 gas mission, and NaOH has no any effect of the control of both gases.

Jan 1, 2009

By Viviane Tavares

The technology advance of mobile devices makes consumers of these equipment do more constant exchanges, with this the obsolete devices discarding becomes an environmental problem, due its landfill accumulation. In order to minimize the environmental impacts caused by these equipment there?s the recycling necessity of polymers, ceramic and metallic materials. The main goal of this recycling is to study the printed circuit board of device mobile processing through ore treatment in order to recoup copper. Initially printed circuit boards were processed in a knives mill, in order to liberate the ferrous material, after that it was done the magnetic separation of the reduced residue. With the not magnetic fraction it was done the grain sized analysis and sulfuric acid and hydrogen peroxide leaching analysis. With the chemical analysis results proceeding from the leaching aliquot it was possible to observe that the leaching method with sulfuric acid and hydrogen peroxide presented greater copper recovery.

Jan 1, 2009

By George P. Demopoulos

In this paper the production and stability of crystalline scorodite (FeAsO4·2H2O) is discussed both on the basis of previously published work as well as recent work performed in our laboratory. The production of scorodite, especially from arsenic-rich and iron-deficient sulphate solutions offers a number of operational advantages such as high arsenic content, stoichiometriciron demand, and excellent dewatering characteristics. In addition to hydrothermal production of scorodite the work done over the last 10 years in our laboratory has determined that it is feasible to produce scorodite by step-wise lime neutralization at 90°C. The atmospheric scorodite possesses the same structural and solubility characteristics with the hydrothermally produced scorodite. Long term equilibration tests (up to 66 weeks) in the pH range 5 to 9 and temperatures from 22 °C to 75 °C revealed scorodite to undergo slow incongruent dissolutionyielding a highly metastable nano-sized 2-line ferrihydrite phase. The equilibrium arsenic concentration with this phase was 0.35, 0.96 and 5.87 mg/L at pH 5, 6, and 7 respectively at 22°C. In the presence of gypsum slightly lower concentrations were measured, this being more pronounced at pH>7. It was tentatively deduced that a Fe-Ca-AsO4 association (in the form of a phase resembling the mineral yukonite) contributes to the lowering of As concentration. Finally thermodynamic calculations determined that scorodite is stable in the presence of ferrihydriteunder oxic conditions up to pH 6.75 at 22 °C or higher pH at lower temperature and gypsum-saturated solutions. Keywords: Scorodite, Crystallization, Arsenic, Solubility, Stability, Precipitation, Disposal, Extraction, Processing, Metals, and Environment.

Jan 1, 2005

By Junji Shibata

Keywords: Synergistic effect, Solvent extraction, Nickel ion, extractant mixture Waste solution from the Ni non-electric plating process contains 4.0 kg/m3 Ni (II), 0.1 kg/m3 Fe (III), 0.01 kg/m3 Zn (II), 48 kg/m3 SO42-, 98 kg/m3 HPO32- and 31 kg/m3 lactic acid as a typical composition. Solvent extraction, cementation, ion exchange resin and precipitation methods may be used for the treatment of this kind of solution. In this study, solvent extraction of Ni (II) is investigated by using two kinds of extractants in order to clarify the relationship between extraction equilibrium (static synergistic effect) and extraction rate (dynamic synergistic effect) for several extractant mixtures. The static synergistic effect does not take place significantly for the extractant mixtures of acidic extractants and neutral organphosphorous compounds, while a large static synergistic effect is confirmed when the extractant mixtures of acidic extractants and nitrogen-containing compounds are used. Nickel ions can be extracted in the wide pH range of 3.0-8.0 without any pH adjustment by using the several extractant mixtures. At the same time, the extraction rate remarkably increases by using the extractant mixtures of acidic extractants and nitrogen-containing compounds.

Jan 1, 2005

By Christophe Thiébaut

Keywords: Pyrochemistry, Salts Treatment, Distillation The pyrochemical purification of metal generates spent salts. When this metal is an actinide such as plutonium, the slags cannot be discarded and are thus disposed in nuclear facility. In order to handle with these slags, the decision has been taken to reduce stored quantities. The development of a pyrochemical treatment is in progress in the CEA Valduc centre. The feed salt, typically composed of various Pu and Am species contained into monovalent or divalent chloride matrix, is first oxidized to convert the actinides into oxides. Then the chlorides are separated from the actinide oxides by vacuum distillation. Temperatures higher than 750°C for monochloride salts mixture NaCl/KCl and higher than 1100°C for divalent CaCl2 base salts, are required to produce an industrial flow of vaporization. Inactive qualification of the process for NaCl/KCl base salt has been carried out with lanthanide surrogates. Then, a pilot equipment, called distillator has been designed and built for production-scale distillation of NaCl/KCl and CaCl2 oxidized plutonium salts. Industrial flows of vaporization have been obtained with this pilot equipment : about 4 g/cm²/h for NaCl/KCl at 800?900°C and 1 Pa, and more than 1,5 g/cm²/h for CaCl2 base salts between 1000?1200°C at 0.1 Pa. The last step, now in progress, is the integration of the distillator into a glove box.

Jan 1, 2005

By W. G. Davenport

The flash furnace is used for smelting concentrate to (i) high-Cu matte and (ii) molten metallic copper. It is also used for converting solidified/crushed matte to molten metallic copper. This is flash converting. It consists (Table 20.1, Fig. 20.1) of: (a)tapping molten 65 to 72% Cu matte from a flash smelting furnace (b) granulating the molten matte to ?1/2 mm particles in a 103 m3/hour water torrent (c) crushing the granulated matte to 50 µm in a vertical roller mill (d)drying the crushed matte (e) feeding the dry particulate matte to a second flash furnace for oxidation converting to molten copper. In 2000, flash converting is being used by Kennecott Utah Copper (George, et al; 1995; Newman et al, 1998, 1999a,b). A second installation is being designed for the Chuquicamata smelter (www.outokumpu.com [October 12, 2000]), The potential uses of flash converting are: (a) as the second half of a flash smelting/flash converting coppermaking sequence (b) as a continuous converting alternative to batch submerged tuyere converting. This chapter uses our flash furnace matrix to determine the %O2-in-blast, industrial oxygen and oil requirements for converting solidified 65% and 72% Cu matte to molten copper. It then discusses choice of feed matte grade and other aspects of the process.

Jan 1, 2001

By Jin Qiu

Experiments were performed to determine the extent of minor element elimination that occurred when mixtures of copper smelter dust and copper concentrate, were calcined under vacuum. Almost complete removal of the As, Sb, Bi and Pb occurred due to the conversion of the minor element compounds of these elements into their highly volatile sulphides by reaction with sulphur from the concentrate. Heat and mass balance calculations of the slag-blow in a copper converter found that ~30 tonnes of the vacuum calcine could be used to produce 100 tonnes of copper as white metal. The use of dirty concentrate as the sulphidizing agent in the vacuum calcination means that the minor element treatment capacity of the smelter complex could be increased by 60 %. Also the productivity of the converters may be increased by up to 8 % due to the supply of copper values and oxygen in the calcined mixture.

Jan 1, 2005

By Purushottam Kumar

Keywords: Magnetostriction, magnetic properties, Pd(Fe,Co,Ni) single crystals Fe-Pd, Co-Pd and Ni-Pd alloy systems show appreciable magnetostrictive strains that are of interest for sensor applications. These systems exhibit congruent melting minima. In this work the magnetic and magnetostrictive behavior of congruent melting Fe-Pd, Co-Pd, and Ni-Pd compositions have been examined. The alloys examined include Fe-54.9 at.-% Pd, Ni-45.4 at.-% Pd, and Co-45 at.-% Pd. The paper describes the growth of bulk single crystals of these alloys using Czochralski technique. X-ray diffractometer was used to obtain rocking curves that were used to determine the [001] crystal direction. Magnetostriction in [001] direction was measured using strain gages. Magnetic properties were measured using a vibrating sample magnetometer. Ni-Pd showed the highest magnetostriction values among the congruent melting compositions. Magnetic and magnetostrictive behaviors of these alloy single crystals are presented.

Jan 1, 2005

By Evgenii Pavlov, Ivan Tronin, Viktor Timofeev, Vladimir Kislov, Sergei Bogovalov

"Modeling of the magnetohydrodynamical (MHD) and thermodynamical processes during the industrial scale Direct Chill (DC) casting of aluminum slabs is performed using a combination of ANSYS/CFX and ANSYS/EMAG software. The electromagnetic field is modeled through ANSYS/EMAG, while hydrodynamic and thermodynamic processes are modeled through ANSYS/CFX. Both packages were modified in order to calculate MHD flows in the liquid pool that forms during aluminum DC casting, and they were unified into a software combination that provides simultaneous simulation of all the above processes. The simulation shows that the electromagnetic stirring of the molten aluminum changes the shape of the solidification front (solid-liquid interface) very dramatically, namely it becomes significantly flatter. This effect should improve the internal structure of aluminum DC slabs and allows us to increase the casting velocity.IntroductionProduction of Aluminum alloys with high mechanical properties and structural uniformity is one of the main goals of industry. The preferred production method of aluminum alloys in most modern plants is Direct Chill (hereafter DC) casting because it offers high productivity and commercial success. One important limitation of this technology is the development of centerline shrinkage in slabs larger than about 1 meter. The improvement of the internal structure of long DC cast slabs can be achieved by electromagnetic stirring (hereafter ES) of the liquid metal above the solidification front. This intensifies heat transport in the zone close to the solidification front and suppresses shrinkage formation."

Jan 1, 2013

By Licheng Zhou

The use of aquatic plants for the removal of heavy metals from wastewater has gained high interest. In this study, batch experiments were conducted to evaluate the adsorption of copper ions in aqueous solution by P. pectinatus L. under various conditions of contact time, initial pH of the solution, metal concentration and adsorbent dosage. The results showed that the maximum adsorption amount of copper ions by P. pectinatus L. was 22.60 mg/g when the initial copper ions concentration was 98.41 mg/L at pH 4.5. The Langmuir and Freundlich models were used to describe the adsorption equilibrium of copper ions on P. pectinatus L. and the adsorption followed the Langmuir isotherm. The adsorption kinetic was well-fitted with pseudo-second-order sorption equations.

Jan 1, 2009

By Sayavur Bakhtiyarov

Keywords: Rheology, Viscoelastic, Oil In this paper we present the results of the rheological property measurements on viscoelastic composite materials used in oil industry. Laboratory experiments were carried out to determine important thermophysical, rheological and mechanical properties of the test materials using both the standard commercial and in-house made equipment. The composites with the paramagnetic particles (?-iron oxide) are exhibited a significant magnetic memory after magnetic treatment. The measured value of the yield stress after the magnetic treatment increased almost twice in comparison with the yield stress value of the magnetically untreated composite. The yield stress of the composite material exponentially decreases with time and reaches its magnetically untreated value after 15 hours. The yield stress also increases with the amount of the paramagnetic powder additive, and it reaches a maximum value at 8 wt-% of this additive. The obtained results provide valuable information for computer modeling of the viscoelastic fluid flow in pipes of complex geometry.

Jan 1, 2005

By Qiang Zhang

Hybrid composites are fabricated by adding two reinforcements into matrix materials so that the expected excellent properties can be achieved through the combined advantages of short fibers, and different size particles (micron or submicron), which provide a high degree of design freedom. In this paper, hybrid preforms were produced with the different size reinforcement of the Al2O3 particles and short fibers. The Al-Si alloy-based hybrid composites were fabricated by preform-squeezing casting route. The structure and performance of composite materials were studied with the Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). The results show that the reinforcements, both particles and fibers, distribute homogeneously in the matrix materials, and the properties of composites are found to improve in comparison with the matrix Al-Si alloy.

Jan 1, 2009