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By Z. Smieszek, J. Botor, Z. Miczkowski, S. Sobierajski

"From 1978, the direct process for the smelting of chalcocite concentrates in a flash furnace by the Outokumpu method has been applied at the Glogów II copper smelter. The chemical composition of these concentrates make it necessary to control the process very strictly. In this paper, the method for controlling and measuring the main technological parameters of the copper production by flash smelting is being presented. It includes the determination of the chemical composition of the concentrate, its grain structure, the temperature of liquid products of the process, oxygen content in process gases, as well as lead concentration in copper and copper concentration in slag.The main process parameters are determined from the mass and energy balances. The relations between parameters, such as an effect of grain structure of a concentrate on oxygen and oil consumption, and dependence of chemical composition of a concentrate on capacity and products quality are discussed. 1. IntroductionThe Polish copper concentrates, as most concentrates occurring worldwide, contain from 18% to 30% Cu, and less sulphur (7-11%) and iron (2-5%). The main copper-bearing mineral contained in the concentrates is chalcocite, while bornite and chalcopyrite are present in smaller quantities. Moreover, the organic carbon (5-7.5%), arsenic (0.05-0.3%) and lead (1.2-3.0%) are also contained in the concentrates. The gangue consists mainly of silica, aluminosilicates, calcium carbonate and magnesium carbonate. Their proportions make the addition of slag-forming agents unnecessary.The composition of Polish concentrates, especially their low iron content, allows their application in the direct flash smelting process for blister copper production. Low sulphur content is the factor which determines the necessity of oxygen application in this process."

Jan 1, 1989

By B. S. Terry

Experiments have been conducted to assess the feasibility of capturing bearing emissions arsenic with CaO during the roasting of enargite (Cu3AsS4). Enargite/CaO mixtures have been heat treated in air, nitrogen or oxygen for various times and the products of reaction analysed by X-ray diffraction and cleaned analysis. The results show that substantial capture of arsenic can be achieved via the formation of calcium arsenates and/or calcium arsenides. In addition significant capture of sulphur is achieved by the formation of calcium sulphate andlor sulphide. Complete conversion to copper sulphide with total removal of arsenic can be achieved within 30 minutes at 700°C. Further heat treatment in air or oxygen leads to the formation of copper oxide and copper oxysulphate. Without optimisation of reaction conditions, it has proved possible to achieve retention of in excess of 85% of the arsenic content of enargite in the form of calcium arsenates.

Jan 1, 1994

By Seyed Ahmad Jenabali-Jahromi

In this paper a meshless method called Finite Point Method (FPM) is developed to simulate the solidification process of continuously cast bloom steel in both primary and secondary cooling region. The method is based on the use of a weighted least-square interpolation procedure. A transverse slice of bloom as it moves with casting speed is considered as computational domain. The two dimensional heat transfer equation together with temperature dependent thermophysical properties is solved in the computational domain. The present work is verified in the mold region by the comparison of the surface temperature simulated by FPM and finite volume method (FVM) and also comparison of solidified shell thickness simulated by FPM and measured on a breakout bloom. For secondary cooling region the validation is done by comparison of the surface temperature simulated by FPM, FVM and thermovision measurements.

Jan 1, 2009

By Warren J. Bruckard, Mark I. Pownceby, Sazzad Ahmad, M. Akbar Rhamdhani

Rutile is the preferred feedstock for producing high-grade TiO2 pigment but due to decreasing resources, alternative materials such as ilmenite is now used to produce a synthetic rutile (SR) feedstock. This requires removal of impurities (e.g. Fe, Mg, Mn) which, for a primary ilmenite is straightforward process. Processing of weathered ilmenite however, is complex, especially when chrome-bearing impurities are present since minor chromium downgrades the SR market value as it imparts color to the final TiO2 pigment, Chrome-bearing spinels are a problem in weathered ilmenites from the Murray Basin, Australia as their physical and chemical properties overlap with ilmenite making separation difficult. In this paper, different sulfidation process routes for weathered ilmenites are analyzed for their applicability to Murray Basin deposits as a mean of remove chrome spinel impurities. Thermodynamic and experimental studies indicated that selective sulfidation of chrome-bearing spinel can be achieved under controlled pO2 and pS2 processing conditions thereby making them amenable to separation.

Jan 1, 2015

By Keiji Okumura, Jiayi Shan, Jian Yang, Masamichi Sano

"A new method of deoxidation and desulfurization of molten iron with magnesium vapor has been developed. An immersion tube, which was filled with pellets of the mixture of magnesia and carbon powders, was put into the molten iron. Magnesium vapor produced by carbothermic reduction of magnesia inside the tube was injected directly into the molten iron with argon carrier gas. The effects of temperature and carrier gas flow rate on deoxidation and desulfurization were investigated. A mathematical model of the reactions was developed. The rates of deoxidation and desulfurization were controlled by mass transfers of magnesium vapor in the gas-phase and oxygen and sulfur in the liquid-phase. This method may offer high efficiency for magnesium deoxidation and desulfurization of molten iron.IntroductionMagnesium is a strong refining agent in steel-making processes1 • At steelmaking temperatures, magnesium has a very low solubility in liquid iron, and a very high vapour pressure2 • Deoxidation and desulfurization with magnesium take place essentially through the interaction of magnesium vapor with oxygen and sulfur dissolved in molten iron, and magnesium can change chemical composition of nonmetallic inclusions3 • However, addition of magnesium to the steel bath is dangerous and does not give high efficiency in the refining process4 • Furthermore, as a refining agent, the price of magnesium is higher than aluminium and CaO fluxes. In the present study, a new method of the deoxidation and desulfurization of molten iron was developed using magnesium vapour in-situ produced by carbothermic reduction of magnesium oxide. Pellets made of mixture of magnesia and carbon powders were charged into an immersion tube, which was made of alumina or graphite. The magnesium vapor was injected directly into the melt. The effects of pellet mass, experimental temperature and carrier gas flow rate were studied on the refining rate. A mathematical model of the refining reaction was proposed on the basis of the experimental results."

Jan 1, 2000

By E. A. van Dijk

Dusts from steel-making processes contain substantial amounts of zinc. Such dusts are also a hazardous waste and dumping them becomes unacceptable from environmental point of view. Therefore processes that can recover zinc and possibly other metals from steel-making dusts are being investigated. The aim of this paper is a contribution to the more fundamental kinetic aspects of zinc reduction from silica free calcium ferrite slags. The effects of alumina, lime and magnesium oxide contents of the slag, the COICO, ratio and the effect of initial Fe2O3/CaO ratio were studied experimentally at 1400°C The results indicated that the reduction of zinc from molten slag was possibly a first order reaction. As expected higher COICO, ratios increased both the extent and the rate of reduction. It was also observed that a higher iron content of slag improved the reduction of zinc from calcium ferrite slags. This fact seems to support the proposed mechanism that zinc is partly reduced by ferrous iron to zinc vapour and that ferric iron is reduced by carbon monoxide. The reduction rate of zinc in these slags was decreased by increasing alumina content of the slag. Alumina decreased the calculated optical basicity of the slag showing the fact that reduction of zinc oxide was more favorable in more basic slags. Probably the formation of complex ions by alumina and zinc oxide such as ZnAl2O32+ lowers the activity of Zn2+ ions in the slag and hence render them more difficult to reduce.

Jan 1, 1999

By A. Patti, S. Reutzel, D. M. Herlach, L. Ratke, I. Egry

Cu-Co shows a metastable miscibility gap in the region of the undercooled melt. Undercooling of the melt below the binodal leads to separation of the melt into a Co-rich LI-phase and a Curich L2-phase. Experimentally, undercooling into the metastable miscibility gap is realised by means of electromagnetic levitation (EML), processing in drop tube (DT) and by melt flux embedding. As undercooling is large in these experiments, the velocity of the solidification front is high and the microstructure is frozen in instantaneously. Samples have been undercooled and solidified in the TEMPUS-facility (container less electromagnetic processing under weightlessness) during parabolic flight under reduced gravity conditions. Microstructures of solidified samples have been analysed and compared to those processed under gravitational conditions. The influence of convection on phase growth is much lower in reduced gravity. The microstructure shows spherical droplets of the minority phase, statistically dispersed in the majority phase.

Jan 1, 2004

By Desmond Cook, Cynthia P. Dogan, Dale Govier, Gary Korth, James C. Rawers

"The microstructural and mechanical properties of iron powders processed in an attrition mill are highly dependent upon the processing environment. Extended high-energy ball milling in argon resulted in nanocrystalline bcc-Fe microstructure, while processing in nitrogen or alloying with carbon resulted in both nanocrystalline bcc-Fe and bct-Fe microstructures. In this U.S. Bureau of Mines study, both X-ray diffraction and Mössbauer analysis were used to show that the infused carbon and nitrogen concentrations were predominantly on the grain boundaries. Explosive consolidation resulted in a fully dense product with microstructure similar to the microstructure of the mechanically processed powder. Hardness values of the compacts correlated highly with grain size, independent of the processing conditions.IntroductionNanocrystalline materials have been theorized and shown to have unique properties that make them interesting for material scientists and promising for material engineering applications. Several conferences have been devoted solely to the techniques of preparing nanostructured materials have been held(l,2,3.). To date, most techniques used to generate nanocrystalline materials produce only a few grams of particles(1). High-energy ball-milling, however, is an efficient and effective technique that can produce substantial quantities of nanocrystalline materials with homogenous chemical composition that cannot be produced by conventional processing techniques(3).Applications and material evaluations of nanocrystalline materials require several grams of solid samples. Because nanocrystalline microstructures' are thermodynamically unstable, producing consolidated macro structures of nanocrystalline material has proved to be very difficult(2,3). In particular, retention of the nanocrystalline microstructure during consolidation of nanocrystalline particles has proven to be a problem. In contrast to many consolidation techniques that require elevated temperatures, explosive compaction uses a shock wave for consolidation( 4,5)."

Jan 1, 1994

By lonkion M. Font

Due to the known disadvantages of the use of iron silicate slag in the nickel converting stage, i.e., high metal losses, high magnetite content, and low fixation of impurities in the slag, the development of the new proposed "ferrous calcium silicate slag" for smelting and converting processes of nickel is very promising. Hence, considering the successful experimental results of using CaO base slag for the nickel smelting process, a study based on a detailed comparison for the phase equilibrium, and the minor elements distribution between the NilS2-FeS matte with either FeOx-CaO or FeOx-Si02 base slag was investigated. The main results are summarized as: no difference in the nickel losses between both slags was found at high nickel content in the matte, and the fractional distribution analysis for arsenic and antimony pointed out their preferential fixation in the calcium ferrite slag rather than in the iron silicate slag. Considering the energy and pollution issues, the technical feasibility of using calcium ferrite slag in a converting process of the Bessemer matte will have a prominent future for the nickel industry.

Jan 1, 2003

By Torn H. Okabe

A fundamental study was conducted with the purpose of establishing an environmentally sound recovery process for recycling of valuable metals, by combining scraps containing such metals. As an example, direct extraction and recovery of neodymium (Nd) in magnet scraps was investigated by utilizing liquid metal as an extraction medium. It was found that liquid magnesium (Mg) is a suitable extraction medium and can extract Nd from iron alloys with high efficiency at around I 100 K. The newly developed extraction apparatus for Nd is a mechanically simple and static device without moving parts, where the Mg extraction medium circulates due to differences in the temperature inside the reaction vessel. This developed device can simultaneously accomplish continuous extraction of metal Nd from scraps, re-extraction of Mg from Mg-Nd alloy and the eventual recovery of pure Mg. As a result, metal Nd with 98 % purity was directly recovered from magnet scraps under certain conditions. It was also shown that the extraction agent Mg could be reused. The results of this investigation show the possibility of establishing a new process for the direct extraction of Nd in pure metal form without oxidization.

Jan 1, 2003

By A. G. Jackson, S. J. P. Laube

"Control of thin films during the growth process is dependent on several parameters that are difficult to monitor, including flux of film material, pressure, substrate temperature, composition, and thickness. One means for easing this difficulty is to take advantage of emission spectra associated with the process and the film. For pulsed laser deposition (PLD), the ion cloud generated by the laser has characteristic emission spectra that can be used to control the flux and, hence, the film. For chemical vapor deposition, the species present can be determined using mass spectroscopy and specific peaks can be used to control the deposition. Raman spectroscopy affords the possibility of real-time control by sensing characteristic peaks associated with film composition and thickness. These spectroscopic methods offer a real-time alternative to process control that is very attractive, because of the ability to accurately control films to achieve the engineered structures and properties sought. Examples are presented to illustrate the capabilities of these methods for thin film preparation.IntroductionThe drive to reduce costs and improve efficiencies of operation sets the tone for much of research, basic or applied. Basic research is limited by the ability of sensors and associated instrumentation to measure parameters accurately and reproducibly. Applied research has the same limitations and also the added constraints of time and costs. Hence, there are strong incentives to explore means for refining existing sensors with respect to performance and cost, as well as finding new sensors and techniques for more accurately and rapidly measuring quantities of interest in experiments and in various processes."

Jan 1, 1997

By Kazuyuki Kikuta

MMAJ, a govemmental organization in Japan, has carried out a 4 year project for the development of the decontamination and metals recovering technology for the fly ashes from municipal waste incineration. Heavy metals (zinc, lead and copper) are recovered as raw materials for the non-ferrous metals production, without formation of any waste materials to be disposed. More than 500 thousands tonnes a year of fly ashes generation from the municipal waste incineration has been one of the main social issues in Japan, because most of them need to be disposed to the registered areas after decontamination, and occupy 5% of the municipal wastes disposed. The segregation, flotation and chemical process are applied to the treatment of the primary fly ash from municipal waste incineration, and MF (Mitsui-type blast furnace) Process after the chlorine removal to the secondary fly ash. The main results of experiments are -About 90% of heavy metals, zinc, lead and copper, can be recovered from the primary and the secondary fly ashes to the products for the non-ferrous metals production. -Both of the leaching residue from the primary fly ash treatment and the slag from the secondary fly ash treatment can be used as a raw material for the cement production, meaning that the decontamination technology for the ashes without the landfill has been established. -Dioxins in the primary ash can be decomposed satisfactorily, and the dioxins content in the segregation furnace gas is less than O.lng-TEQ/Nm3 without any gas cleaning system

Jan 1, 2003

By C. F. Feng, L. Froyen

"In-situ processes have emerged as new and promising techniques for metal matrix composite fabrication. They offer significant technical and economic advantages over conventional processing. One of the in-situ processing routes that have been used is reactive free sintering of a mixture of powder reactants. However, materials synthesised via this route are always porous because of density differences between reactants and products. An example are the porous Al/(TiB2+Ah03) MMCs obtained by heating powder mixtures of Al+ Ti02+B with Ti02 and B in stoichiometric ratios for forming TiB2• In this study, porous Al/(TiB2+Ah03) composites were further processed by hot-pressing at temperatures above 600°C. This processing cycle was designed so that the composites could be densified. Furthermore, the reaction kinetics of the in-situ processing are studied by means of DSC analysis measured at different heating rates. The activation energies of the three intermediate steps that are involved in the reactive processing for preparing AV(TiB2+Alz03) MMCs are determined to be 923 kJ/mole, 241 kJ/mole and 235 kJ/mole respectively.XRD proved that the hot-pressed products consist of Al, TiB2 and Al203- Properties of the products are assessed by microstructural characterisation (LOM, SEM and EDS), microhardness, Young's modulus and bending tests. The results show that good microstructures, elastic properties and strengths, as well as acceptable ductilities were achieved. For the composition 79.74wt% Al-15.95wt% Ti0z-4.31wt% B, after the reactive free-sintering and hot-pressing cycles, Young's modulus is 105 GPa, bending strength is 509 MPa and maximum strain is 5.0%; for composition 88.73wt% Al-8.87wt% Ti0z-2.40wt% B, they are 89 GPa, 311 MPa and 8.2% respectively. It can be seen that the properties of products can be tailored by adjusting the relative amounts of reactants in green samples. Furthermore, for comparison reasons, Al and a binary system Al-Ti02 were identically processed as the ternary systems. Their microstructures and properties were studied."

Jan 1, 1998

By A. Onozaki

The Iijima Refinery was put into operation in 1972 and today has an annual production capacity of 156,000 tons of SHG electrolytic zinc. At the Iijima Refinery, the recoveries of gold and silver are 98.0% and 98.2%, respectively. Gold contained originally in the zinc concentrates reports in the Cu-Pb-Ag residue produced in the residue treatment process. Silver contained in the concentrates is distributed between the Cu-Pb~Ag residue and the copper cake produced in the purification process. The Cu-Pb-Ag residue, which contains gold and silver, is sent to the Oyachi flotatfon plant of the Kosaka Smelter; about 82% of the gold and about 85% of the silver are recovered in the copper flotation concentrate.. In this paper, the distribution of gold and silver in the Iijima. Refinery is discussed and operational results of the Oyachi flotation plant are presented.

Jan 1, 1990

By Bror Nyrnan

Solvent extraction technology and equipment have been developed within Outokumpu since the early seventies. During this period altogether nine solvent extraction processes for molybdenium, zinc, rhenium, cobalt, nickel, calcium and magnesium have been commercially adopted in Outokumpu's metallurgical plants. During last years a new mixer-settler concept based on a "Vertical Smooth Flow" (VSF) principle has been developed. It has also been found to be a good method for copper solvent extraction, decreasing essentially the crud formation and the organic and aqueous entrainments.

Jan 1, 1994

By Hector Henao

To provide thermodynamic data for converting the nickel matte to liquid nickel, an experimental study was conducted in the phase equilibrium between the Ni-S alloy and the CaO-Al2O3 based slag melted in a MgO crucible at 1873 K under controlled Pso2 of 10.1 kPa and Po2 in a range between 2.5x 10-and 10.1 Pa by using CO-CO2-SO2 gas mixtures. The content of nickel in the slag at Po, of 10.1 Pa, above which solid NiO is expected to precipitate in the equilibrium state, was found to be 4, I mass% and the contents of sulfur and oxygen in the nickel melt were 0.4 and 02 mass%, respectively. ft was clarified that increase in the temperature reduces the solubility of nickel in the slag and the contents of sulfur and oxygen in the alloy, The distribution of minor elements such as gold, silver, copper, cobalt, iron, arsenic and antimony between the Ni-S alloy and the CaO-Al2O3 based slag was also studied. The distribution ratios of iron and cobalt, defined by (%X in slag)/[%X in alloy] where X is the minor element, are larger values than that of nickel, while those of copper, silver and antimony are similar to that of nickel. The distribution ratios of arsenic and gold are lower than that of nickel in the higher range of oxygen partial pressure.

Jan 1, 2003

By J. L. Jambor

Sulfide-rich tailings accumulated in a 4l-hectare impoundment at the Waite Amulet minesite near Noranda, Quebec, have undergone partial oxidation and destruction of the principal sulfides (pyrite and pyrrhotite) in the vadose zone. Mineralogical studies and whole-rock chemical analyses of 18 samples from 3 boreholes along a cross-section of the tailings pile indicate that the principal chemical manifestations of the alteration are a pronounced depletion in sulfide-sulfur, and an enrichment in total Fe as Fe203' Other elements such as Al, Mn, Mg, Ca, Na, and K in the solids show erratic or inconsistent variations, but a trend to Si enrichment in the oxidation zone is clear. The trend is interpreted to be a relative enrichment whereby the proportion of the stable silicate minerals has increased as a consequence of the consumption of pyrite and pyrrhotite in the oxide zone.

Jan 1, 1989

By Jose M. Gomez-Vega, Osamu Takai, Atsushi Hozumi, Hiroyuki Sugimura

"Ongoing research is reported aimed at improving the properties of mesoporous silica-based coatings on various substrates for optoelectronic or medical applications. Tetraethylorthosilicate (TEOS) was selected as the silica precursor, and amphiphilic triblock copolymers poly( ethylene oxide)- poly(propylene oxide)poly( ethylene oxide) as the surfactant micellar template or structure-directing agents. Cetyltrimethylammonium chloride (CTAC) was also used as a control agent. The effect of the templating agent and type of substrate (glass, Si, and Ti) on the mesoporosity, particularly on the alignment of the mesochannels, has been investigated. Three · different treatments (thermocalcination, photocalcination, and solvent extraction) have been also studied to remove the organic templates.IntroductionThe fabrication of mesoporous silicate-based materials through the utilization of a sol-gel process, where cooperative organization of organic and inorganic species takes place, provides a versatile approach to nanoscaled structures with potential applications in fields such as catalysts, optoelectronics, biomaterials, etc. Compared to conventional low molecular weight surfactants, self assembly of amphiphilic·block copolymers can result in mesostructured materials with larger pore sizes (up to 30 nm).1 Most of the synthetic strategies use silicon alkoxides as the silica precursor, although non-silicate metal alkoxides, e.g; Ti, Zr, Al, and B, have been also used to obtain different mesoporous materials, or even mixed metallic oxide systems. 2 Recently, Yang et al. 3 • 4 were able to synthesii:e a great variety of mesoporous metal oxides ID nonaqueous media using inorganic precursors (metal chlorides) and block copolymers as structure-directing agents."

Jan 1, 2000

By Kazuhiro Nisizono, Takashi Kuroki, Nobuyuki Mori, Keisaku Ogi

"The improvement of critical current density and mechanical property is essential to the practical application of the superconductive oxides. A solidification technique is developed in this study for the growth of columnar or single Y123 crystal with finely dispersed Y211 and Ag particles through a monotecto-peritectic reaction of Li.(Ba-Cu-Ag-0 rich liquid)+ Y211-+ Y123+Lz(Ag rich liquid). The large solidification rate and temperature gradient can refine the Ag and Y211 particles. But Ag-free region is widely formed along the crystal growth direction in the central part of the Y123 cell. Since this phenomenon occurs because of the cellular growth, it is necessary to narrow Y123 cell width or to grow Y123 crystal with flat freezing interface. By controlling crystal growth direction using a seed crystal, Y123 columnar or single crystal with uniformly dispersed fine Ag particles are obtained. The· behavior of Ag and Y211 particles during the solidification of Y123 crystal is simulated by the peritectic growth model of faceted Y123 crystals.IntroductionY-Ba-Cu-0 superconducting oxide (YBCO) with high critical temperature also has excellent superconducting characteristic under the high magnetic field. The critical current density (Jc) has been enhanced by ·using unidirectional-solidification technique, which can overcome the weak-link problem at grain boundaries and control the crystal orientation and the distribution of Y211 particles which give effective magnetic flux pinning centers in the Yl23 matrix [1-4].In addition to improving superconducting properties, it is necessary to improve mechanical property for the practical application. The silver addition to the melt-textured YBCO superconducting oxide has been reported as the effective method to improve mechanical properties without degrading superconducting properties. Since the material properties are considered to be largely affected by silver particle size, form, dispersion state etc. in the Y123 phase, it is important to control Ag distribution in YBCO/Ag composites. Besides, it is also reported that the silver addition improve the corrosion resistance to the water and CO2 [5,6]. Nishizono et al. [7-9] have reported that the silver distribution in the YBCO/Ag composites is largely affected by the solidification condition, but yet some unclear points are also remained. YBCO has been also fabricated by the zone melting method [10-12], and Furuya et al. [5] and Hirano et al. [13] have reported the fabrication of silver added YBCO composites, but the distribution and behavior of Ag are not investigated in detail"

Jan 1, 2000

By Michael I. Morris

The U.S. Department of Energy's (DOE's) Transuranic and Mixed Waste Focus Area (TMFA), funded from fiscal year (FY) 1996 though FY 2002, was tasked with finding solutions for the mixed waste treatment problems of the DOE complex. During TMFA's initial technical baseline development process, three of the top four technology deficiencies identified were the need for amalgamation, stabilization, and separation/removal technologies for the treatment of mercury-contaminated mixed waste. The Mercury Working Group (HgWG), a selected group of representatives from DOE sites with significant mercury waste inventories, assisted TMFA in soliciting, identifying, initiating, and managing efforts to address these areas. Solicitations and contract awards were made to the private sector to demonstrate both the amalgamation and stabilization processes using actual mixed wastes. The goal was to develop separation and removal processes that will address DOE's needs. This paper discusses the technology selection process, development activities, and the accomplishments of TMF A through these various activities.

Jan 1, 2003