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By H. Hirayama, T. Okura, O. Kato

"Saganoseki Smelter & Refinery, one of the largest copper smelters in the world, has the annual capacity of 300,000 metric tons in copper content with two flash furnaces, six Pierce-Smith type converters, two anode furnaces, four acid plants, three tank houses and perfect pollution control system.Coping with the many severe conditions surrounding the copper industry in the last decade, Saganoseki Smelter has kept performing the stable operation, while enhancing the smelting capacity and developing new technologies such as the hydrometallurgical treating of converter dust recovered at electric precipitators. Especially in the operation of flash furnaces, which are of Nippon Mining's conversion type using hot air in a temperature of l,000ºC some technological improvements and complete operation control factors have approved the concentrate feed rate to reach to 2,200 tons a day for a flash furnace.Reported in this paper are the production control design for copper smelting process, and the operation control scheme of the flash furnace following the brief review of the characteristic of Saganoseki Smelter's process and some improvements. Copper Smelting ProcessDescriptions of major unit operations and general specifications of the copper smelting facilities are summarized in Table 1, and the present flowsheet of the copper smelting is described in Figure 1 (1,2).Outputs and raw materials treated in the last five years are shown in Table 2, in which concentrate includes powder copper scrap which amounts to 3 to 4% of concentrate.A full operation was performed for a period of one month, for both one flash furnace operation and for two flash furnace operation. With one furnace operation, 19,200 tons of copper were produced. With the two furnace operation, 84,000 tons of concentrates were charged and 33,500 tons of anode (net 28,600 tons of copper) were produced.The actual production level, however, has been kept at 80 to 90% of the full capacity because of low copper price, tight market of copper concentrate or fall of net demand in Japan."

Jan 1, 1989

By Jennifer Mager, G. P. Martins, Dean Mussatti

"The role of lead, at low concentrations in high pH cyanide-electrolytes, on the dissolution behavior of gold, has been a topic of scientific and industrial concern for well over a century. The recent paper by Kondos et al [1] at CANMET (1995) this continuing interest and apparent importance. Nevertheless, the mechanism(s) by which this (and other heavy metal) component influences the electrodics of this electrochemical system has still not been unequivocally demonstrated. Instead, several plausible hypotheses, by pioneering researchers in this field, have been advanced and reiterated OVer the ensuing years. While it is generally accepted, based on equilibrium elctrode-potential calculations, that reduction (or co-reduction when oxygen is present in the electrolyte) of lead on the gold surface may occur due to cementation (contact reduction), the cemented lead has never been characterized. The work presented has reexamined the role of lead in this system, by delineating the species distribution of these system components and by interpreting the results of potentiodynamic studies in conjunction with SEM analyses of a gold electrode.1. INTRODUCTIONThe leaching of gold ores in cyanide electrolytes has been practiced for well over a 100 years. Research conducted on this topic has been primarily focused on the effects of operating parameters such as concentrations of oxygen and cyanide, and the pH of the electrolyte; or the leaching behavior of carbonaceous and sulfitic gold-bearing materials.Mechanisms by which pure gold is leached in alkaline cyanide media, with oxygen serving as the oxidant, have been subjected to continual examination and re-examination in the published technical literature during this century. Recently, it has been speculated that without the presence in the electrolyte of trace heavy metals, such as lead or mercury, that gold would not be leachable. Researchers who have tackled this topic, have either considered heavy metals to be a natural occurrence in these systems and ignored the role they may serve in the leaching process, or they have deliberately focussed on controlling their concentrations in the system to undetectable limits. As a result, conflicting findings have been reported for what would appear - depending on the details provided in these reports - to be identical systems."

Jan 1, 1997

By Kimio Itagaki

The distribution behaviours of the VA elements between the gas, slag and matte phases in copper smelting were evaluated on the basis of the thermodynamic data, most of which were determined by the authors. The distribution is basically dependent on the process factors such as temperature, the content of the element in charge, the amount of the waste gas and degree of vapour saturation with the elements. The thermodynamic quantities such as the activity coefficients of the VA elements in matte, the activities of iron and copper, SO2 or 02 potential and the distribution ratio of the elements between the slag and matte phases seriously affect the distribution, and the behaviours in various smelters could be explained systematically and reasonably by considering the changes in these quantities, In oxidation smelting at PSO2= 0.1 to 1 atm, the proportion of arsenic and bismuth in gas is predomi22t for the arsenic and bismuth distributions in both smelting and converting stages. The degree of vapour saturation has serious effect on the distribution, and sufficient contact between gas and matte phases is desirable for transferring arsenic and bismuth into gas phase.The elimination of antimony by means of vaporization is not significant. In reduction smelting at po2 = 10-11 atm, the proportions of arsenic and antimony in the gas phase are quite small, but the proportion of bismuth does not change significantly.

Jan 1, 1983

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 C. B. Solnordal, R. N. Taylor

"The heat transfer conditions on the outer side of a Sirosmelt lance have been determined using experimental measurements in combination with a mathematical model. By measuring the temperature distribution along the wall of an operating Sirosmelt lance, as well as the thickness of the slag layer on it, it was possible to use the model to determine both the heat transfer coefficient between the vessel contents and the lance, as well as the effective thermal conductivity of the slag layer. The effective thermal conductivity of the slag layer was found to be within the range 0.7-1.3 W.m-1. ºCl, which was in good agreement with measured values for magnetite. The outside heat transfer coefficient varied from 80 to ISO W.m-2. ºC1, which was smaller than quoted in the literature for metal/slag systems. The discrepancy was attributed to the high thermal resistance experienced between the lance wall and the slag layer, as well as the large quantities of combustion gases that envelop the lance tip and reduce convection and conduction from the melt to the lance. INTRODUCTIONThe Sirosmelt submerged combustion smelting process [1] utilizes top injection lances to deliver fuel and air into a metallurgical melt. To help prevent lance failure from attack by liquid slag, helical vane swirlers are used within the annular lance to impart swirl to the flowing air and enhance the heat transfer from the lance wall to the air. The swirlers thus cool the wall, and enable a frozen layer of slag to form on its outer surface. This solid layer ensures liquid slag cannot reach the lance surface, and the lance is protected.A mathematical model of the heat transfer processes associated with the lance has been developed, which combines heat balance equations with engineering correlations to predict the wall and cooling air temperature of the lance, as well as the air pressure distribution. An account of the model was given by Rankin et al. [2]. To further enhance the model and enable it to predict the thickness of slag accumulating on the lance, a detailed analysis of the heat flow through the slag layer commenced in 1992. By far the most complex aspect of the model, the flow of heat from the vessel contents to the outside of the lance was dependent on many factors, including:-"

Jan 1, 1996

Carbon injection into metallurgical slag is important in electric arc furnace (EAF) steelmaking for foamy slag practices and in nonferrous slag cleaning operations. The current publication presents kinetic data for coal injection into EAF slag to understand the interaction between injected carbon and metallurgical slag. Coal particles were injected into EAF slag and the kinetics were followed by gas and slag analysis. The results were analyzed, in terms of fundamental rate equations for each possible reaction step, as a function of temperature and slag composition.

Jan 1, 2003

By Shoji Taniguchi, Lifeng Zhang, Kaike Cai

"In the present paper, based on the two-phase (Eulerian-Eulerian) model, the 3D fluid flows in gas-stirred systems, i.e., air-stirred water vessel and argon-stirred liquid steel ladle, are simulated. In the Eulerian-Eulerian two-phase model, gas and liquid are considered to be two different continuous fields. The phases are assumed to share space in proportion to their volume fractions. The exchange between the phases is represented by source terms in conversation equations. Turbulence simulated by the k- e model is assumed to be the property of the liquid phase. The following effects of mathematical treatments and operational factors on the fluid flow are discussed, such as interphase drag force, turbulent model, the size of bubble, and gas injection mode.Some interesting results are derived. Except the interphase drag force, the interphase lift force should be taken into accounted in order to exactly simulate the fluid flow in gas-stirred systems. Suitable turbulent model and drag coefficient have effect on the mathematical simulation. Injecting small bubbles can realize a well mixing flow condition. The distance between the two gas-injection nozzles has effect on the fluid flow."

Jan 1, 2000

By Huaming Yang

Infrared materials are a special kind of material widely used in military, biological engineering and chemical industry. However, the problems associated with them such as unstable properties, high cost and a high thermal expansion coefficient seriously restrict the development and the wide application of the traditional infrared materials with the SiC or ZrSiO4 matrix. The ultrafine quartz powder is normally used to prepare the infrared materials by hot-pressing technology. The aim of the paper is to investigate the thermal expansivity, the effect of the SiO2 size and the addition of AI2O) or Fe2O3 on the infrared emissivity of the quartz matrix of the infrared material (QMIM) in a 8-25um wavelength range. The results indicate that 89% of infrared emissivity and 0.4x 10.5°C of thermal expansion coefficient of QMIM can be obtained. The affeeting mechanism of Al2O) and Fe2O3 on the infrared emissivity of QMIM were also discussed.

Jan 1, 2003

By Huaming Yang

Infrared materials are a special kind of material widely used in military, biological engineering and chemical industry. However, the problems associated with them such as unstable properties, high cost and a high thermal expansion coefficient seriously restrict the development and the wide application of the traditional infrared materials with the SiC or ZrSiO4 matrix. The ultrafine quartz powder is normally used to prepare the infrared materials by hot-pressing technology. The aim of the paper is to investigate the thermal expansivity, the effect of the SiO2 size and the addition of Al2O3 or Fe2O3 on the infrared emissivity of the quartz matrix of the infrared material (QMIM) in a 8-25um wavelength range. The results indicate that 89% of infrared emissivity and 0.4x 10-5/°C of thermal expansion coefficient of QMIM can be obtained. The affecting mechanism of A1203 and Fe2O3 on the infrared emissivity of QMIM were also discussed.

Jan 1, 2003

By M. Z. Sukiennik

A static method for vapor pressure measurement up to 1450 K and above 1 hPa is presented. The method is designed for equilibrium and kinetic studies of metallic systems, including those with a chemical reaction. Application examples are given for determination of activities in condensed phases, and heterogeneous reaction rates and equilibrium constants.

Jan 1, 1993

By Zhijing Zhang, Ramana G. Reddy

"The viscosity of molten oxides is one of the important physical properties since viscosity has a decisive influence on fluid flow. The knowledge of the viscosity of molten oxides is essential for modeling and controlling of metallurgical process. In the present study, viscosities of high basic Na2O-B2O3 and Na2O-SiO2 binary melts and viscosities of Na2O-SiO2-B2O3 ternary melts were measured as a function of temperature and composition. Experiments were carried out using rotary viscometer and graphite components. Our experimental results were compared with those in literature. Based on the current experimental data, the previously developed viscosity model was modified. The characteristic features of viscosities of these melts have been discussed. The predicted viscosity results are in excellent agreement with the present experimental data in the temperature range with molten state samples. IntroductionThe viscosity of molten oxides is one of the important physical properties since this property has a decisive influence on fluid flow, and is one of key factors to be taken into consideration in process modeling. The manufacturing operations require the viscosity of molten oxides to be within certain ranges. Although, some viscosity measurements on borosilicate systems have been carried out [1-4], the viscosity data in literature are available only for a few temperatures and cover small composition ranges. The agreement between the results of these works is not satisfactory [I-4]. Even the viscosities of binary systems Na2O-B2O 3 and Na2O-SiO2 generally are well studied, the available viscosity data in literature are only found in the composition range of O to 0.333 mole fraction ofNa2O. The aim of the present study is to provide a base with accurate experimental data for reliable model extrapolation."

Jan 1, 1999

By Hang Goo Kim

A mathematical analysis based on equilibrium modeling has been developed to describe the distribution behavior of minor elements such as Pb, Zn, Bi, Sb, and As among gas, slag and recovered copper phases during the reduction of copper oxide in slag cleaning with CO gas. The results show that large fractions of the impurities transferred to slag during smelting or converting are recycled to the recovered copper metal. It is also shown that there is a limit to the recovery of copper from slag because iron oxides are also reduced to form a copper-iron alloy at low oxygen potentials. The effects of various operating parameters such as temperature, the activity of FeO, the initial amounts of the elements in the slag and CO content in process gas, on the behavior of these minor elements are discussed. The predicted results were compared with the results of a pilot plant operation in which pulverized coal was used as a reductant. Consistent trends between the two cases were obtained.

Jan 1, 1992

By Junzo Hino

Most of the waste that contains a small portion of copper is landfilled. The recycling process of copper from the waste, such as shredder residue, should be developed in order to save mineral resources and prevent environmental pollution. Shredder residue, generated from disposed automobiles and electric appliances, consists of many types of plastics, glasses and metals. The combustion heat of plastics is efficiently used for smelting in the recycling process that consists of melting and reduction. Because the waste contains numerous components the knowledge of the distribution behaviors of the main components is necessary to develop the recycling process. The distribution behaviors in the recycling process are evaluated by using the thermodynamic calculation program, HSC Chemistry. The calculation results are compared with the practical operation data of the recycling process and discussed.

Jan 1, 2003

By Batric Pesic

Adsorption of gold on activated carbon from gold bromide solutions was examined as a function of pH, particle size, carbon amount, initial gold bromide concentration, bromine concentration, temperature, and various cations and anions. pH did not have any effect below pH=6. Above pH=6, pH had dramatically negative effect. The adsorption results satisfied a first reaction order model. The reaction rate constant was proportional to the inverse of carbon particle radius. It was also proportional to the amount of carbon, and independent of initial gold concentration. Temperature had a very little effect at pH=l. At pH=8, the activation energy was a function of the extent of a reaction, increasing with the extent of a reaction. Cu, Fe, Ca, Mg, and Na cations and sulfate, chloride and bromide anions did not have any effect on gold adsorption. Bromine had a very negative effect on gold uptake.

Jan 1, 1991

By Zhen Zhang, Jiang Diao, Tao Zhang, Yi Ren, Lu Jiang, Xiao-Man Yan, Bing Xie

The precipitation behavior of phosphorus enrichment phase was investigated by slag modification with Al2O3. The mineral phase of the original slag and modified slags were measured by mineral phase microscope, SEM+EDS and XRD. The mechanism of Al2O3 modification was discussed according to the thermodynamic theory analysis software (Factsage version 6.3). The results show that the high phosphorus solid solution (nˊ2CaO·SiO2-3CaO·P2O5) was generated by the continuous reaction of nC2S-C3P (nˊ＜n) solid solution and Al2O3 under 1350℃. The amount of initially precipitated solid solution (nC2S-C3P) was reduced and even disappeared with the increasing of Al2O3. If the addition of Al2O3 is enough in the slag, the high phosphorus solid solution (nˊC2S-C3P) that generated by the above mentioned reaction will continue to react with Al2O3 to produce Ca2Al2SiO7 and even C3P, which was demonstrated that the addition of Al2O3 has a positive influence on the precipitation of phosphorus enrichment phase.

Jan 1, 2015

By Roger Altman

The solubility of copper in primary spinel crystals encountered in reverberatory slag samples has been determined by electron microprobe analysis. These spinels, which ranged in composition from 22% A12O3 to pure magnetite, contained small quantities of dissolved copper (0-0.4%). Based on literature data it was estimated that the solubility limit of copper in solid magnetite is no greater than about 1% at 1200°C and about 2% at 1250°C. However, it was found that practically every spinel crystal examined contained significant amounts of matte inclusions. Further examination of converter slag revealed large quantities of irregularly shaped precipitated magnetite crystals which contained a large proportion of copper inclusions. Additional experimentation showed that the total copper content in reverberatory slag samples was greater than the sum of the estimated en- trained plus dissolved matte in the slag. This difference is believed to be significant and is due to the presence of matte inclusions in the spinel crystals. In the present reverberatory slag samples these inclusions accounted for about 1/2 of the amount of sulfide directly entrained in the slag.

Jan 1, 1976

By K. Narayan Prabhu, W. D. Griffiths

"Heat transfer during the unidirectional solidification of a cast iron alloy against cast iron chills was investigated using an inverse modelling approach. Chills of thickness 100 mm and 10 mm were used, to simulate gravity die cruiting conditions and the use of chills in sand moulds. In both cases transient heat transfer, measured by the interfacial heat flux and heat transfer coeffieient; declined from initially high values in the first few seconds of solidification, to values about an order of magnitude lower which persisted for the remainder of the experiments. In the case of the thin chill it became saturated with heat until it was no longer in a position to extract further heat from ·the casting. These results were interpreted by studying the resistance to heat transfer from the casting offered by the ·casting-chill interface and the chill itself for example, the thermal resistance of the casting-chill interface can be influenced by the deformation of their respective surfaces and their subsequent relationship.IntroductionDie casting cast iron offers several advantages such as energy savings, higher mould yield, and better surface quality over the sand casting process1 • The process is· environmentally' friendly because of the elimination of the sand. However the design and construction of metallic moulds is expensive and a faulty die design may result in a defective casting: A simulation based process design of die castings would enable die designers and solidification modellings to try better designs of dies on the computer and arrive at a cost effective solution more quickly. This has numerous benefits for the die caster, as he would be able to produce sound castings with very short lead times.The success of a solidification model to predict accurately the thermal history and the location of hot, spots inside a solidifying casting depends to a large extent on the heat transfer data prescribed at the metal/mould interface. Many measurements of the heat transfer coeffident (or the heat flux) between a solidifying aluminum alloy and a chill have shown that the heat transfer coefficient is a function of most of the variables of the casting process2 - 8. However heat transfer studies during the solidification of ferrous alloys are rather limited. The high temperatures involved suggest that the contribution due to radiation heat transfer cannot be neglected."

Jan 1, 2000

By R. H. Crist

Reactive components of algal cell walls include uronic and alginic acids: In addition, many marine species have half ester sulfate groups which function as fixed anions. Associated metals vary with the media, eg., Ca and Mg in fresh water (FV) and Na, Ca, Mg in seawater. . These metals readily exchange with aqueous phase protons or metal cations. A plot of the total amount of metal cations displaced by protons vs .. pH shows one inflection at pH 4 for FV algae and&apos; in addition a second inflection at pH 2, 3 for marine algae. The first inflection is interpreted as. Indicating the cations associated with carboxyl groups ,and the ,second with half ester ?Sulfate groups. The exchange capacities of various aigal ,species vary widely. When FV algae is placed in a Pb2+ solution,- the amount of Pb2"&apos; deposited on the algae is. Equivalent to the. Total Ca2?, Mg2, and H+ displaced? thereby confirming the ion exchange mechanism. Ion exchange equilibrium constants are reported for the displacement of ca2+ from Vaucheria. With Mg2+, sr2+, Cd2+, Pb2+_ and Na+ as well as the reverse reactions. Cd2+ can .be removed partially from algae by precipitating it as CdS or Cd(OH) 2 Pb2+ and Cu2+ are also partially removed as the hydroxides. Rates of reaction for various alkali hydroxides decrease with increasing .unhydrated cation radius. It is concluded that theory is useful in predicting viable applications for algae in pollution abatement.

Jan 1, 1991

By S. N. Ojha, Gouthama, R. K. Mandal

"Spray deposition processing of liquid immiscible alloys, based on AI-Pb and Cu-Pb systems have been investigated. Process variables have been optimized to generate uniform dispersion of ultrafine second phase particles in· the matrix of the primary phase. Mechanisms governing the microstructural evolution in this synthesis methodology are discussed. Results of the present investigation are used to demonstrate that rapid solidification of atomized droplets initially provides a high nucleation rate of the second phase during the liquid phase separation. The solid matrix phase nucleates at a later stage and grows with a high velocity enabling trapping of the dispersed phase. Subsequent alteration in the size and size distribution of the second phase is suggested to arise further during deposition of high velocity droplets. Possible reasons for this effect are brought out. Microstructural features of atomized powders and spray-deposits of these alloys are presented to support the present approach of synthesizing composites. IntroductionIn recent years, synthesis of advanced materials with metastable microstructures and ultra fine dispersion of second phase particles has led to the development of novel techniques of materials processing. The other requirement of such a processing methodology is to achieve near-net shape geometries in less number of processing steps. The solidification processing method via spray deposition route qualifies these criteria. This process primarily involves atomization of a melt by high energy gas jets into spray of droplets which are subsequently propelled by the kinetic energy of the gas towards a deposition substrate to build-up a thick high density preform. Although the concept of spray deposition was pioneered by Singer [1] in the early seventies, the fundamentals of the deposition process has been understood only recently [2-4]. Several benefits of spray deposition processing are by now well established [5,6]. Rapid solidification effects are inherent in spray deposition processing due to high heat exchange rate at the droplet-gas interface and also on the deposition surface by force convection. Since considerable heat extraction occurs from the atomized spray prior to droplet consolidation, a relatively low processing temperature is ensured in this process. As a result deleterious coarsening phenomenon can be minimized. In addition, controlled maneuvering of the substrate provides the capability of the process in producing disc, sheet or tube shape preforms of difficult to work materials in a single operation. A significant improvement in properties, resulting from microstructural homogeneity and refinement in grain size induced by spray deposition has been reported for several alloy systems [7,8]."

Jan 1, 1994

By Ramana G. Reddy

Thermodynamic modeling and experimental study on impurity capacities and their distribution between mattes or metal and slags in smelting, converting and refining of non-ferrous metals was discussed. A brief review on the recent developments in copper smelting and converting is presented. The analysis showed that, copper smelting capacity increased by a factor of 10 since 60&apos;s, smelting rate increased by a factor of more than 5 and process fuel equivalent decreased by a factor of 2. A thermodynamic model for prediction of impurities capacities in slags and their distribution in mattes and slags was developed. The impurities capacities (i.e. sulfur and arsenic) of slags were calculated a priori with no adjustable parameters using the Reddy-Blander model. The capacities predictions were made in a wide range of matte and slag compositions, Pso, and temperatures in conditions pertaining to copper and lead industrial slags. The calculated results for sulfide and arsenate capacities are in good agreement with the available experimental and industrial copper and lead industrial slags data. The sulfide and arsenate capacities in copper slags (fayalite, ferrite and olivine) and lead slags are reviewed. The application of RB model predicted ratios of 02 and S2 partial pressures in industrial copper smelting processes are discussed. Application of this model for the prediction of Sb, Bi and other impurity capacities and their distribution ratios in mattes or metal and slags, in industrial smelting and refining processes is discussed.

Jan 1, 2003