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By A. Pagliero

The coulombimetric reduction method has been used as an evaluation technique for Pb-Ca-Sn anode corrosion in the LIX-SX-EW process. The proposed methodology involves three consecutive steps, i.e., cleaning, oxidation and reduction. They are carried out in the same experimental unit, in solutions containing 180 g/L H2S04 with and without the addition of cobalt. The authors have worked in a wide range of oxidation current densities, from 150 to 500 A/m2 for in a period from 0.5 to 120 hours. It can be concluded from the results that there would be a linear relationship between the applied electrical charge I*T (Coulomb) and the anode corrosion expressed as transformed Pb mass (mg), for solutions with or without the addition of cobalt. The exception is that for the last one the corrosion rate is 5 times faster, which was observed for every layer. From the evaluation of different corrosion layers, one can point out that its composition is mainly in the form of sulphate. In the presence of cobalt, about 67% of Pb would be as sulphate (PbSO4), about 27% as a basic oxide (PbO) and only 6% as oxide PbO2 on the surface. From this result, it appears that great transformations occurred in the metal/sulphate interface. Without the addition of cobalt, the proportion of oxide Pb02 on the surface increased up to 11.5%. According to the previous statement and considering that Pb was found mainly as sulphate, the authors recommend its determination be used as quality selection criterion. Its evaluation should be performed in the acid solutions with 200 ppm cobalt addition at an oxidation current density of 300 A/m2 for a period of 24 hours.

Jan 1, 1999

By K. C. Liddell, B. Dou

"In producing multilayer films for magnetic data storage applications, the interfacial roughness must be controlled in order to obtain high quality materials with reproducible properties. The present understanding of the effect of roughness on multilayer properties such as magnetoresistance is sketchy, particularly for electrodeposited films. In this study, quantitative atomic force microscopy was used to characterize surface morphology before and after Ni films of varying thickness were deposited on Cu cathodes. A multinuclear multilayer growth mechanism is supported by both the deposition conditions and the AFM images, and a multinuclear multilayer model gave a satisfactory fit to measurements of the density of peaks on ultrathin Ni films between 0 and 8 nm thick.Alloys consisting of alternating ferro-and paramagnetic layers have begun to replace Permalloy in the sensing elements of magnetic hard drives. The operating principle of the new read heads is giant magnetoresistance (GMR), and they are smaller and more sensitive than previous inductive heads (1). Experimental studies on sputtered multilayers have emphasized the role of layer thickness and interlayer roughness in determining the presence and size of the GMR effect (e.g., 2,3,4,5,6). However, roughness in electrodeposited multilayers has rarely been measured, even though read heads are likely to continue to be made by this process for some time to come. Cu/Ni can be considered a model system for understanding processing-microstructure-property relationships in electrodeposited multilayers and is the most widely investigated of all such systems (e.g., 7,8,9,10,11,12). Nevertheless, the roughness of the interfaces in Cu/Ni electrodeposits has not been systematically characterized by quantitative techniques, and in all studies reported so far, the total deposit thicknesses were considerably greater than the 10 nm needed for most sensor applications (1). The thinnest such films were about 50 nm (7)."

Jan 1, 1998

By Maura Malone, Neil Gao, Daniel Liu

"Corrosion is the primary failure mode for aluminum cathode sheets used in Teck's Trail Operations electrolytic zinc plant. It was observed that the corrosion performance of Al cathodes from different suppliers varied considerably. This suggests that the material properties of Al cathodes have a strong influence on corrosion resistance. In the current study, various types of Al alloys, including 1050, 1060, 1070, HIS and 1090, were characterized through chemical analysis, corrosion testing, mechanical testing and metallography. The results are discussed with a focus on the effects of impurity elements and second phase particles on corrosion resistance. The findings were used to improve the Al cathode sheet specification and to develop a standardized screening procedure which details qualification steps for comprehensive evaluation prior to a plant trial.IntroductionAluminum (Al) cathode replacement is a major operating expense at Teck's Trail Operations zinc electrolytic plant. Currently, approximately 0.5% of daily stripped Al cathodes are removed from service because of failures caused mainly by corrosion. Edge corrosion and acid (solution) line corrosion are the most severe types of corrosion, resulting in more than 50% of cathode failures.Corrosion of Al cathodes has been intensively investigated for over two decades and the origins and mechanisms of Al cathode corrosion are well understood [1-4]. Halide anions contained in the electrolyte are the primary culprits for the corrosion and sticking problems of Al cathodes. Both fluoride (F') and chloride (Cl"") result in localized passivity breakdown on the surface of the Al cathode, causing pitting corrosion. Bouarzaiga investigated the corrosion of Al cathode samples partially immersed in electrolyte and found that the formation of Ch at the electrolyte/air interface was the primary contributor to solution line corrosion [2]. Because of the significant impact of F"" and Cl"" on Al cathode corrosion, it is imperative to maintain these concentrations as low as possible in the electrolyte."

Jan 1, 2012

By Hiroshi Nakajima, Kotobu Nagai, Toshihiro Hanamura

"Low carbon ferritic steel bars with ultra-fine grain structure was developed through a warm rolling for the first time by the present authors. They show better low temperature toughness than conventionally hot-rolled plates. Hence, the brittle fracture surfaces in Charpy tests were examined in terms of the effective grain size of fracture, compared with those of conventional QT steels. The ductile-to-brittle transition temperatures were in good accordance with those for the QT steels if referred to the effective grain size of fracture: · However, the size was a few times that of the ferrite grain. This means the grain refining is not yet fully utilized from the viewpoint of low temperature toughness. The anisotropy of· the impact properties and the annealing effect of highly dislocated structure on the toughness are also discussed in the present paper.IntroductionFor structural materials, both high strength and good toughness are required. Well-known approaches for obtaining better toughness for steels are as follows:1) Grain refining2) Addition of Ni3) Thin plate effect by cracking parallel to the rolling direction prior to crack propagation4) Contribution of metastable austenite.Among them, only the grain refining can raise the strength and improve the toughness. And it is well known that the finer the ferrite grain size, the lower the ductile-to-brittle transition temperature. For example, in the case of 0.11 carbon steel, the transition temperature decreases linearly to in d 1/2 [1 ]. However, these have been told in the regime of coarse grain size that is larger than 10 µm in diameter. There ~as .been no study dealing with the low temperature toughness in the regime of ultra-fine grain size with a diameter in the order of 1 µm."

Jan 1, 2000

By Honggang Zhong, Xin Cao, Qijie Zhai, Hongmei Song, Congsen Wu, Cheng Zhang, Jingzheng Ye

"The influence of superheat on the solidification structure and ferrite/austenite phase transformation of a novel lean duplex stainless steel (DSS) was investigated on a setup, which designed to thermally simulate the continuous casting process. The results showed that the macrostructure of the samples all exhibited chill zone, columnar zone and equiaxed zone. The distance from chill zone to position of columnar to equiaxed transition (CET) moved from 51.0 mm to 39.8 mm with an decrease of superheat from 70 °C to 10 °C, and that the grains in the chill zone tended to be finer. In equiaxed zone, the fme and uniform grains were observed when superheat higher than 40 °C; while, coarse grains were found in samples poured at low superheat. Generally, the volume fraction of ferrite increased along the dendritic growth direction, and stabilized in equiaxed zone. The high superheat decreased the volume fraction of ferrite in equiaxed zone, while it had indistinctive influence on chill zone and columnar zone.IntroductionDuplex stainless steel with approximately equal volume of ferrite and austenite, offering an attractive combination of corrosion resistance and mechanical properties. [ l]. The production of DSS, worldwide application in structural engineering[2] and petrochemical industry[3], have increase by more than 100% in the latest decade[4]. But due to the sharp prices increase of nickel and chromium, lean duplex stainless steels which have lower contents of alloy elements were developed. They perform well in both mechanical and corrosion resistance[S, 6] and even have TRlP(Transformation Induced Plasticity) effect[?]. Nonetheless , the mechanical properties of DSS was affected greatly by the solidification structure, such as columnar to equiaxed transition (CET), grain size and phase content[8]. So, the solidification behavior of stainless steel was investigated widely"

Jan 1, 2014

By M. Tamura, K. Fujita, K Shinozuka, H. Daimon, H. Esaka

"In-situ observation of unidirectional solidification using transparent substance has been performed to investigate the growth direction of solid phase. Cell or dendrite of which preferred growth direction is not parallel to the heat flow direction was observed with various solidification conditions. Dimensionless growth direction (p) changes from 0 to 1 with increasing growth velocity at a constant temperature gradient. Introducing the dimensionless growth velocity, the relation between p and growth condition could be correlated.IntroductionTransition in macroscopic solidified structure from chill to columnar zone which is found in normal castings takes place via grain selection1). Cast products such as turbine blades are unidirectionally solidified, grain selection plays an important role to choose suitable crystals which have reasonable orientation in the region called ""starter"", which is a very initial part of casting2). Therefore, grain selection is a very important process in the formation of casting structure. The present authors have been studying on the process of grain selection using succinonitrile, which is a transparent organic substance and have found that the growth distance necessary for grain selection depends upon the solidification condition3-5). When the solid/liquid interface is dendritic, the grain selection occurs quickly. On the other hand, when the solid/liquid interface is cellular, it occurs slowly. We supposed that the growth direction of dendrite is different from that of cell when the substance is unidirectionally solidified. Indeed, Kurz and Fisher wrote in their text book that dendrite grows along its preferred growth direction, <100>, regardless of heat flow direction and that cell grows along heat flow direction regardless of its preferred growth direction1). However, there is no quantitative description about the growth direction when the solid/liquid interfacial morphology is cellular. Furthermore, there have been little works6) to study the growth direction of cell and dendrite."

Jan 1, 2000

By Hiroaki Kawamura, Takeshi Yoshikawa, Kazuki Morita, Yutaka Yanaba

"To develop an alternative metallurgical process for phosphorus removal in the production of solar-grade silicon (SOG-Si), slag treatment of metallurgical-grade silicon (MG-Si) was conducted, followed by acid leaching. Phosphorus-doped silicon alloy or MG-Si containing certain amounts of phosphorus and calcium was reacted at 1723 K and 1773 K with CaO--CaF2 of several compositions. Phosphorus removal from the molten silicon into the slag phase was confirmed by reduction to phosphide ions, P3-, and phosphate ions, P3-. These ions were separately determined using a wet chemical analysis method developed by ourselves. The highest phosphorus distribution ratio obtained was 2. 7 after reaction for 18 h with 17.5 mass% CaO--CaF2 slag. We then conducted acid leaching of the silicon and achieved removal of a large fraction (over 90 % ) of the phosphorus, which was much higher than that obtained by ordinary oxidizing slag treatment.IntroductionIn recent years, the production of solar cells has been increasing rapidly. Because of this, the demand for solar-grade silicon (SOG-Si) has also been growing rapidly. The development of lower-cost mass production processes is therefore needed to provide silicon feedstock. Phosphorus is one of the impurities in metallurgical-grade silicon (MG-Si). Because of its large segregation coefficient (kp = 0.35) [l ], it is difficult to remove phosphorus using a solidification refining process. Vacuum melting is considered to be a promising method for removing phosphorous from MG-Si [2], but the issues of high cost and large energy consumption have still to be resolved.Slag treatment is often used to remove impurity elements by oxidizing reactions during general oxidation refining processes. For example, phosphorus in molten steel is removed into a slag phase as phosphate ions, PO4 3-l-, by the following reaction:"

Jan 1, 2013

By Carlos G. Levi

"The principles involved in the rapid solidification of supercooled metal droplets and existing numerical models are reviewed. The limitations of these models for studying alloy solidification are discussed in terms of the effects of alloying elements on the relevant heat transfer, thermodynamic and kinetic parameters. Analysis of the enthalpy-temperature diagram reveals how the extent of rapid solidification is hindered by the addition of solute. A solidification model incorporating thermodynamic and kinetic relationships into a Newtonian heat transfer formulation is used to analyze the thermal history and concurrent solute redistribution during recalescence. IntroductionIt is well acknowledged that microstructural evolution during solidification is intimately associated with the thermal history of the liquid-solid interface. Structural parameters like chemical homogeneity, morphology and size scale of the phases can be related to the interfacial temperature and velocity. These in turn change by the interaction of the interface with the thermal and solutal fields in its neighboring environment.The thermal history of powder solidification can be conveniently described on the enthalpy-temperature diagram for a pure metal shown in Figure 1 and discussed in detail elsewhere [1). A system can conceivably follow any path of decreasing enthalpy in the supercooled region of Figure 1 (~ < 1), starting at the nucleation temperature (oN < 0) on the liquid line, and ending at some point on the solid line. A vertical path represents an isothermal transformation, of which a limiting case is solidification without significant barriers to nucleation and growth, with the interface at the equilibrium temperature TM (path one in Figure 1). A horizontal path represents isenthalpic (or adiabatic) solidification whereby the system could form an amount of solid proportional to the initial supercooling of the liquid without further heat loss to the environment. A liquid that can completely transform to solid under adiabatic conditions is said to be ""hypercooled""."

Jan 1, 1986

By Jesús Contreras

Since the commencement of its activities in Huelva in 1970, Atlantic Copper has maintained a course of action that has been more demanding than the successive environmental legislations current at different times. As its primary objective it has sought compatibility between the protection of the environment and both its industrial activity and the social and economic development of the area in which its Metallurgical Complex is located. For this reason, since the seventies it has maintained a continuous programme of investments which have allowed it to attain its present environmental situation. As a consequence of the Environmental Policy of Atlantic Copper, in April 1998 it obtained certification for its Integrated System of Environmental Management (SIGMA) according to international standard IS0-14001, and under European Community Regulation 1836/93 (replaced by the 76112001) for the Eco-Management and Eco-Audit System (EMAS). The SIGMA formalises the environmental management practices of Atlantic Copper and engages it to have available a system that can be fully audited. Atlantic Copper was the first European Company in the non-ferrous metallurgical sector to obtain both the UNE-EN-ISO 14001 certification and the EMAS registration. The present paper reviews the actions by Atlantic Copper in environmental matters that have allowed it to achieve its present position. It also describes the coming stages of improvement planned and the modifications to be carried out in the near future, in particular the criteria for the selection of technologies on the basis of the concept of BAT (Best Available Techniques) introduced by the European Union, and always guided by the final objective of converting Atlantic Copper into a reference within the sector, comparable to the best designed and operated installations in the world.

Jan 1, 2003

By Hideki Yamamoto, Junji Shibata

"The chemical reactions of fluoride and chloride gases with metal chloride or metal oxide are utilized as an effective treatment for harmless disposal. These chemical reactions can be adopted in the temperature range of 80°C~400°C, which is lower than that in the combustion treatment (800°C). Reaction products are metal fluoride or metal chloride which are a harmless and a valuable chemical material as one of new resources. This paper, concerns with a new harmless disposal treatment of toxic global warming gases.IntroductionNew technology to make fluoride and chloride gases such as NF3, CF4, SF6 BF3, Cl2 and BCl3 harmless has been developed and a new concept on the removing toxic gas to be used in the advanced process of materials has been established. The fluoride gases ~re toxic and special type of gases to be used in the process of manufacturing semiconductors and their specific applications include the dry etching of semiconductors, cleaning of CVD systems, an oxidation agent for rocket fuel etc. Especially, NF3 is also attracting an attention as a high-energy source for chemical laser systems. As a fluoride gas like NF3 is, however; toxic and highly stable chemically, if discharged into the atmosphere, it is liable to cause far-reaching adverse influences on global warming in the same manner as carbon dioxide gas and feron gas.Up till now, the combustion treatment method has been adopted for the disposal of the gas, and when treating the gas by high-temperature combustion (800""C), the generation of nitrogen oxides (NOx), sulfur oxides (SOx) and hydrogen fluoride (HF) have been confirmed: These chemical substances are not only linked with an intense c0rrosion of the combustion systems but also create the generation of atmospheric pollution and acid rains, and therefore, constitute a serious social issue."

Jan 1, 2000

By Hongbo Zhu, Kun Yang, Jingyan Jia, Jinhui Peng, Libo Zhang, Yi Xia

"Titanium dioxide is broadly considered as the most potential useful photocatalytic material. In this work, titanium dioxide was synthetized by microwave solid-state method and characterized by thermogravimetry-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result demonstrates that through microwave solid-state synthesis, we can obtain uniform size and anatase TiO2 photocatalyst, with the precursor being Ti(C2O4)2·2H2O. And its degradation kinetic parameter of MO can reach to 0.21232.IntroductionSince Fujishima and Honda found the photovoltaic property of titanium dioxide TiO2 [l], it has been widely used in the field of pollutant degradation, virus killer and environment protection [2-5]. Compared to other semiconductors, TiO2 has the advantage of low toxicity/cost, chemical stability, excellent photocatalytic activity, and long lifetime of electron/hole pairs, thus it is considered to be a most potential useful photocatalyst material [ 6]. Solid-state synthesis of oxide nanoparticle is a new method developed in recent years, which not only overcomes the shortcomings of easily aggregation existing in traditional hydrometallurgical process, but also fully demonstrates the unique technologic advantages of without solvents, high yield, easy control, less environmental pollution in solid-state reaction [7-11]. Researches show that the new method of microwave synthesis shows a lot of advantages such as fast reaction rate, efficient, high purity of product, uniform morphology, energy-efficient, and nonpolluting [12-15].In this work, we associated microwave heating and solid-state synthesis to prepare TiO2 photocatalyst material. Its photocatalytic activity was studied in the degradation of MO queous solution. Meanwhile, the formation process as well as the crystal structure and morphology of the synthesized powders were characterized by means of chermogravimetrydifferential scanning calorimetry (TG-DSC), X-ray diffractometry (XRD) and scanning electron microscopy (SEM) techniques."

Jan 1, 2014

By Paul O. Malan

"The Tusc gold deposit is located along the Carlin Trend approximately 13 kilometers north of Carlin, Nevada and 2.5 kilometers northwest of the Gold Quarry mine. Tusc is one of several structurally controlled oxide gold deposits located along the Good Hope fault within the Maggie Creek subdistrict. Mining commenced in 1994 with an oxide reserve of780,000 troy ounces of gold at an average grade of 1.34 g/t Au. The Good Hope fault forms the southwestern edge of the Schroeder Mountain uplift (also known as the Carlin Window) and juxtaposes carbonate rocks of the Siluro-Devonian Roberts Mountains Formation against siliceous mudstone, siltstone, and silty limestone of the Devonian Rodeo Creek unit. Submicroscopic gold mineralization is disseminated in the Good Hope fault system and in fractured hanging wall carbonate rocks. Wallrock alteration includes silicification, deca!cification, sericitization, and late alunite replacement and veins. All Tusc ore is transported 2.5 kilometers to Gold Quarry for processing. Leach-grade ore (0.2 - 1.7 g/t gold) is placed on the oxide leach pads, and mill-grade ore(> 1.7 g/t gold) is processed through the CIL oxide mill. IntroductionThe Tusc gold deposit is located in Eureka County, Nevada, U.S. A, approximately 13 kilometers north of the town of Carlin and 2.5 kilometers northwest of the Gold Quarry mine (Fig. 1 ). Tusc is one of several open-pit, oxide, gold deposits within the Maggie Creek subdistrict of the Carlin Trend. Tusc is a structurally controlled gold deposit located along the Good Hope fault. Submicroscopic gold mineralization is disseminated in the brecciated and silicified Good Hope fault zone and along intersecting northeast and northwest striking structures."

Jan 1, 1997

By Fu-Shen Zhang, Mengjun Chen, Jianxin Zhu

"In the present study, different types of cathode ray tube (CRT) glasses were examined by sequential extraction combined with TCLP to provide possible explanations for how Pb and Ba leach out from the waste CRT glasses and to give possible reasons for why they leach out. Sequential extraction results showed that Pb and Ba in the CRT glasses dominanfly presented as the residual fraction. The exchangeable fractions of Pb and Ba were extremely low, less than 0.01 % of the total content, but they were higher than those required by the regulation limits, 5 and 100 mg/L for Pb and Ba, respectively. TCLP tests of the original CRT glasses and CRT glasses residues after each step of sequential extraction demonstrated that the extremely high leaching toxicity of CRT glasses mainly caused by its exchangeable and carbonate fractions of Pb and Ba.IntroductionIn recent years, the amount of cathode ray tube (CRT) contained monitors or TV sets in the market were sharply reduced, since they were substituted by novel and better electronic and electric equipments such as LCD and PDP, leaving huge amount of end-of-life CRTs. 50-85% of the total weight of this kind of computer monitor or a TV set is glass[1,2], which was classified to three categories according to their chemical compositions: black & white glass (BW), color panel glass (CP) and color funnel glass (CF)[3]. In order to provide shielding from X-rays generated during the picture projection process, lead, barium and strontium oxides were used in the glass. In general, a color CRT contains 1.6-3.2 kg of lead . Therefore, these glasses have attracted wide and tense attention due to the potential risk to the environment and human health."

Jan 1, 2011

By Dinabandhu Ghosh

The stability diagram of the ternary system Ti-C-O is drawn in the present work for four temperatures, 1473 K, 1573 K, 1673 K and 1873 K, showing the stability fields of TiC, Ti, TiO, Ti2O3 and TiO2. An analysis of the system reveals that it is not possible to produce Ti in a carbon-saturated system; instead, the stable product is TiC. However, Ti can be an equilibrium product in a carbon-unsaturated system at prohibitively low values of pCO and pCO2; for example, at 1873 K, these limiting values are: pCO = 10-6.76 atm and pCO2 = 10-13.36 atm, which, when exceeded, produce TiC and TiO respectively. The magnesiothermic reduction is examined through the stability diagram (log pO2 vs. 1/T) of the system Ti-Mg-O, drawn for a number of pMg values, presenting the pairwise stability fields such as Mg(l) + Ti(s), Mg(v) + Ti(s), MgO(s) + Ti(s), etc. The diagram shows that magnesium reduction of TiO to Ti is possible only at T < 1641 K with pMg = 1 atm and only at T < 1569 K with pMg = 0.5 atm. An experimental scheme for Mg vapor reduction of TiO2 is proposed in which an argon stream is passed over a Mg(liquid) evaporator at temperature T1 (say, 1234 K); the resulting Ar-Mg mixture at 1 atm is subsequently flown over a bed of TiO2 at temperature T2. A thermodynamic analysis establishes that complete reduction to Ti is possible and that the best results are obtained when T1 = T2.

Jan 1, 2006

By František Molnar, Zsolt Szentirmai, Juraj Schmiedl, Felix Sekula

"Hydrometallurgical nickel production in Sered Nickel Plant (Slovakia) that treated roasted Albanian ore left behind a considerable amount of the solid leaching residue. About 6 million tons of this fine-powder residue containing approximately 52 wt.% of iron in the form of oxides is to the present day stored in a stockpile. However, its iron content makes it a potentially interesting secondary raw material for iron production. This secondary raw material is not, unfortunately, suitable for direct treatment in iron and steelmaking processes.This paper presents results of the laboratory tests of pyrometallurgical method of processing of the leaching residue by its roasting and subsequent refining melting. The objective of the selective reducing agglomeration roasting was to reduce iron oxides and to simultaneously avoid reduction of chromium oxides and silica. Refining melting is carried out in an inert atmosphere. The products of melting are technically pure iron and slag.IntroductionThe leaching residue stockpiled on waste dump near already non-existing Nickel Plant Sered, Slovakia, is considered to be one of the most important environmental burdens in this country. The 40-years of an on-going effort focused on finding the methods for extracting metals and thus remove the waste dump have not been successful [1,4,5,6]. From the literature survey it is evident that past investigations have been following three main routes:1.Removal of chromium by mineral processing methods prior to its metallurgical treatment to achieve final chromium concentrations below 0.3 wt.%.2.Pelletization of solid leaching residue and its subsequent reduction in blast furnace and steelmaking plant and simultaneous removal of chromium.3.Pelletization of solid leaching residue followed by metallurgical processing of preliminary reduced semi-product in electric arc furnace (EAF) accompanied by partial reduction of chromium."

Jan 1, 2008

By Robert Kozicki, Eric Graham, George Wrightson

"IntroductionThe manufacture of Ferro Chromium involves the smelting of various ores and fluxes to produce the metallic product.Slag is inherent in the process. It has a much lower density than the metallic FeCr. Some chrome may be trapped in the slag as either FeCr or Cr203.Previous methods to estimate the slag in the FeCr have revolved around separating the slag and metallic portions by exploiting the differences in density. The downside with that procedure is that material will often contain pieces that are adhered FeCr and slag. The Metallic FeCr may also be completely encapsulated in the slag.An alternative and more precise method involves calculating the slag content based on chemical analysis of Mg and Al. The Mg and Al will be at relatively low levels (less than 0.1 % ) in the Metallic FeCr pieces and considerably higher in the slag (3% or greater). The overall sample will have a proportional amount and is calculated using simultaneous equations with the assumption there is only one kind of slag and one kind ofFeCr present. ""Pure"" slag and ""pure"" FeCr are needed in order to determine the Mg and Al in each. The detemlination of the Mg and Al in the overall sample would then be used to calculate the amount of slag.When the particle size is small, it is difficult to sample and get ""pure"" pieces of the slag and FeCr of sufficient quantity to perform a proper analysis. Often, historic data is used but that is dependent on the source of the FeCr and the materials used in its production. Mg and Al levels in slag can vary between 3% and 20% in different FeCr slags depending on their origin."

Jan 1, 2013

By R. Boussaa, Y. Fautrelle, K. Zaidat, O. Budenkova, B. Saadi, X-D. Wang, L. Hachani, H. Ben Hadid

"Comparison of experimental data obtained in a benchmark experiment of solidification of a Sn-3%wt.Pb ingot and numerical results of two-dimensional and three-dimensional simulations of the process is presented. The benchmark experiment consisted in solidifying a rectangular ingot of Sn-3%wt.Pb alloy using two heat exchangers. Conditions of solidification were thoroughly controlled due to six thermocouples embedded into each heat exchanger. Due to another array of thermocouples the evolution of the temperature field at a lateral wall of the crucible was registered during the whole experiment. A treatment of the temperature data provided an estimation of the velocity field in the experiment. Post-mortem analyses of the sample provided the pattern of macrostructure of the sample and qualitative segregations pattern. 2D and 3D numerical solidification models are developed to give the distribution of the solute in a solidified sample.IntroductionConvection, either natural or forced, plays a very important role during the solidification. Its intensity and flow pattern affect heat and mass transfer and, consequently, macrostructure and segregation in a solidified ingot [1-4]. The effect of buoyancy convection during solidification has been studied in many laboratory-scale experiments [5-6]. Due to these experiments a general comprehension of formation of various defects in the ingot has been achieved. However, mentioned studies were not consistent since alloys, solidification conditions and configurations were every time chosen arbitrary. That is why the role of each parameter characterizing solidification process remains unclear. Moreover, the question of reproducibility of defects under the same solidification conditions still exists. In addition, most of the experiments suffer from the insufficient knowledge of control parameters that makes difficult their use for validation of models for solidification. These parameters serve as boundary conditions for numerical modeling and their incomplete description leads unavoidably to the errors in simulations. This situation motivated us to develop a setup for benchmark solidification experiments and to perform a set of the solidification experiments which we reported in [7]. Here we presented a comparison between results obtained in a benchmark experiment of solidification of Sn-3%wtPb ingot and its numerical modeling, which was performed in two-dimensional and three-dimensional configurations."

Jan 1, 2012

By A. V. Kuznetsov, R. I. Kamkin, V. M. Paretskiy, A. Y. Mamaev, V. P. Bystrov, A. S. Vernigora

"Vanukov furnace technology is an efficient, proven pyrometallurgical injection technology, used extensively in Russia and Kazakhstan for a number of different applications. The technology was most widely adopted for processing copper sulfide concentrates for matte in smelters in Norilsk, Revda (Russia) and Balkhash (Kazakhstan). The following applications also were developed and tested at industrial scale: treatment of sulfide lead and lead-zinc concentrates, laterite nickel ore, production of cast iron, treatment of antimony gold-containing ores, and municipal solid waste. In this paper, current experience of Vanukov furnace application to these technologies is described with a number of general development trends and new areas of application.IntroductionAt the present time, the Vanukov process, developed at the Moscow State Institute of Steel and Alloys at the Department of metallurgy of non-ferrous, rare and noble metals with collaboration with other research organizations, is a highly efficient technological solution for processing different kinds of raw materials. The process was invented by Professor Andrey Vladimirovich Vanukov, whose research work began in 1949. From 1956 to 1975 test runs of the technology were carried out at the smelters in Norilsk and Balkhash. In 1976 a pilot Vanukov furnace was built in Ryazan. Furnace designs was modified to suit the various test programs. A major objective of each experiment was the determination of optimal working conditions for processing different types of raw materials such as copper, copper-nickel, copper-zinc, lead or pyrite concentrates, and materials containing secondary lead and zinc. After the death of Andrey Vladimirovich Vanukov in 1986, this technology and furnaces based on the technology were named after him: “Vanukov process” and “Vanukov furnace”. Today, the following furnaces based on Vanukov technology are either working or were tested at semi-industrial scale: three in Norilsk, two in Revda (Russia) and two in Balkhash (Kazakhstan) for treatment of copper sulfide concentrates for matte, one in Orsk (Russia) for processing laterite nickel ore, one in the Buruktal plant (Russia) for antimony gold-containing ores for antimony oxide sublimates and gold-containing metallic antimony, and one in China for processing sulfide lead and lead-zinc concentrates for production of black lead and zinc-containing sublimates."

Jan 1, 2011

By R. Peterson, D. C. Popko, J. Y. Hwang, R. McChesney, A. M. Hein, R. C. Greenlund, M. Jeong

MTU is conducting a study to recycle and reuse the aluminum waste generated from various segments of the aluminum smelting industry. This research is supported by the U.S. Department of Energy and industry. A portion of this effort is to determine the operating efficiencies of Eddy Current Separation, comparing separating characteristics of white and black dross. The results of this effort will be presented here.

Jan 1, 2000

By Caisa Samuelsson, Fredrik Engström, Bo Björkman, Margareta Lidström Larsson

"Large amounts of by-products are generated by the Swedish steel industry each year. The EAF-process generates about 400 000 ton of slag, from which 80% is deposit. An alternative to deposit is to use slag as road construction material. However, metal content in the slag can be a problem, due to the leaching. The aim of this work was to investigate how stable these materials are when ageing and kept outside. Five different EAF-slags from domestic steel plants were used in this study. The materials were characterised after 0, 6, 12, 18 and 24 month to evaluate the ageing process. Scanning electron microscope (SEM), x-ray diffraction pattern (XRD) and a standard test for leaching were used. The changes in behaviour differ between the five materials. The total leachability decreases with time for all samples. CaCO3 is formed on slag surfaces as CaO reacts with moister and CO2 in the air. Introduction The slag generation in the Swedish steel industry is about 1.5 million tonnes annually, of which more than 500 000 ton is generated in EAF (Electric Arc Furnace), AOD- (Argon Oxygen Decarburization) converters and during the refining of steel in the ladle metallurgy. Some of the slags are used in different applications, but most of the steelmaking slags produced in Sweden are landfilled today. The chemistry, mineralogy and physical characteristics of slags make it a suitable material in construction, replacing for example, gravel and rock [1]. In some respects, in road construction, it may even be technically superior to virgin material. Slag from scrapbased steelmaking is used for road construction in Europe. The reason for the low utilization in Sweden is mainly due to potential leaching of harmful elements, legislations and competition with easily available natural raw materials. Except the potential leaching, the technical obstacles for not using some slags in construction include:"

Jan 1, 2008