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By Natasa Mitevska

The distribution coefficients of Ag, As, Au, Bi, Co, Cu, Ni, Pb, Sb, Se, Te, and Zn between copper matte and slag from the reverb furnace No.2 at the Copper Smelter and Refinery, RTB BOR (Yugoslavia), are presented in this paper. The influence of the matte grade on the minor elements distribution coefficients between copper matte and slag is analyzed. The minor elements distribution in the slag phase along the slag melt depth and the furnace length is also determined.

Jan 1, 2002

By P. W. Godbehere

Over the past three years the Horne Smelter has successfully introduced concentrate smelting by injection in Peirce-Smith converters, allowing definitive closure of its last operating reverberatory furnace, while commissioning a large acid plant treating off gases from its Noranda reactor. Future strategies include a major revision to present converter practices to permit further significant reductions in sulphur and dust emissions. This paper gives an overview of the status of these and other technical and operating developments which will further contribute to ensuring the Horne's position as an efficient custom smelter of primary and secondary feeds.

Jan 1, 1993

By David M. Beckwith

Increased globalization and outsource manufacturing complicate the procurement and enforcement of intellectual property rights on a worldwide basis. Recent legislative and case law developments in the United States highlight the importance of a multinational intellectual property strategy. IP lawyers David Beckwith and John Hankins will discuss planning and pitfalls in this rapidly changing trans-border environment. Topics to be discussed include harmonization with international patent laws, protecting your technology and market space with a comprehensive approach to IP, and patent enforcement issues relating to import/export of products and components in the United States.

Jan 1, 2006

By M. D. Street

Lead and zinc production commenced in 1966 at Brunswick Smelting using the Imperial Smelting Process. In 1972 the blast furnace was modified to produce lead bullion only which was refined to corroding grade lead using conventional kettle refining techniques. Since 1972 consumption of lead concentrate and production of refined lead has doubled and this paper describes changes to operating and maintenance techniques which have contributed to this improvement. Reference is also made to improved environmental, health and hygiene practices at the smelter.

Jan 1, 1983

By H. Kurama

In this paper, utilization of fly ash as a value added product in areas such as novel materials, waste management, fillers and agriculture is reviewed with the aim of helping the expand of the usage of fly ash and reduce the environmental and economic impacts of disposal. The used unburned carbon benefication/treatment methods such as low temperature combustion, froth flotation, partical size classification and electrostatic separations to remove unburned carbon particles from fly ash are also discussed.

Jan 1, 2006

By Ivan Van Herpe

"ABSTRACT NOT AVAILABLEPresentation"

Jan 1, 2000

By J. V. Happ

The investigation reported in this paper was prompted by the belief that vacuum processing of copper mattes could provide significant advancement to present-day copper smelting and converting technology. Specifically, vacuum distillation of copper mattes in a unit such as the R.H. vessel used in vacuum degassing of steel, can lead to improvements in: converter flue-gas-cleaning system, purity of acid (or liquid SO2), aisle hygiene, purity of electrorefined copper and smelter flexibility. In the study conducted, removal of Volatile impurities (arsenic, antimony, bismuth, lead and zinc) from liquid mattes, by vacuum distillation in a laboratory-scale equipment was performed. The conditions investigated covered a temperature range of 1123-1223K, absolute pressure of 6.5-0.5kPa (50 - 3 mm Hg) and with bleed gas consisting either of pure oxygen or argon. Six matte samples (four U.S. and two foreign) were tested. Under the "best" conditions arsenic and antimony were reduced to << 0.01% in the product matte. The removal of bismuth, lead and zinc was variable and appeared to be influenced by the matte composition of the sample. As might be expected, the rates of distillation of the various species were increased at higher temperatures and lower absolute pressures. The influence of a small flow rate of gas (02 or Ar) over the melt did not have a signifi¬cant influence on the extent of impurity removal. The magnetite content of the matte was reduced by up to 30% during vacuum treatment and was favored by a low partial pressure of oxygen over the melt. Substantial amounts of sulfur were also evaporated and an, overall increase in copper grade of the matte was realized. The paper concludes with an evaluation of industrial aspects of the process as applied to conventional smelters.

Jan 1, 1983

By Wolfgang Baum

Remediation work on thermal process dusts and slags has been primarily based on chemical analyses. These data offer little information for the assessment of treatability and reuse potential. In addition, the lack of mineralogical residue characterization has frequently caused time-consuming and inefficient waste management. This paper will outline the cost-effective, and sucessful use of process-oriented mineralogical analyses for treatment and beneficial reuse of various thermal residues. These include a patented process for detoxification of Pb-contaminated bottom ash, the pyrometallurgical treatment of K 061, the reprocessing of lead smelter slag as well as various power plant residues.

Jan 1, 1992

By Shun Fujieda, Shigeru Suzuki, Kozo Shinoda, Tetsuo Fujita

"Dowa Metals & Mining Co. Ltd. has developed and plant-practiced a unique scorodite synthesis technology (DMSP®) for arsenic immobilization by oxidizing Fe(ll) ions in the presence of As(V) ions. Dowa has improved the DMSP® technology and has developed the process extensively for other applications. This paper focuses on the applicability of the DMSP® for various cases of copper smelting, and introduces other technologies for fixing arsenic and recycling gallium from GaAs, simultaneously processing (fixing) arsenic and thallium, and fixing and recovering arsenic from dilute arsenic solutions. The DMSP® was found to be applicable not only for various processes in nonferrous smelting, but also for other applications with a high potential for reducing environmental problems.IntroductionDowa Metals & Mining Co. Ltd. developed a method for synthesizing scorodite at ambient pressure [1], The scorodite is precipitated by oxidizing Fe(II) ion in a high-concentration As(V) solution. The scorodite produced in this way does not readily release arsenic because of its high crystallinity. Dowa built a demonstration plant for this technology at the Kosaka Smelter and established the production of scorodite at 30 t As/month by treating intermediate products from copper smelting as the starting material. The DMSP® was demonstrated to be favorably applicable to copper smelting [2]. We are engaged in further increasing the amount of arsenic fixation by the use of this process. Further improvements in productivity, cost reduction and applicability in various processes have been devised. Dowa has been endeavoring to resolve other problems as well as to improve productivity. We have gained extensive knowledge on arsenic treatment in our endeavors, enabling us to solve problems and improve productivity. This paper introduces the investigations and developments related to DMSP®."

Jan 1, 2012

By John E. Dutrizac, Tzong T. Chen

"Laboratory experiments were undertaken to ascertain the behaviour of various ""impurity"" species during the precipitation of hematite directly from ferric sulphate solutions at 225°C and in the presence of 40 or 50 g/L of hematite seed. Copper, nickel and zinc are not significantly incorporated in hematite precipitates. Although the nickel contents increase to 0.22% as the Ni concentration increases to 60 g/L, the solid solution Ni contents are low relative to the bulk Ni contents. Thus, part of the Ni may be present as tiny particles of poorly soluble NiS04.H20. Increasing germanium concentrations to 2,000 mg/L result in products containing up to 0.59% Ge. The Ge occurs either in solid solution in the hematite or is adsorbed on the nanometer-size hematite crystallites. Increasing As(V) concentrations to 10 g/L increase the AsO4 contents of the products up to 16%. However, the products consist of hematite together with As04-containing Fe(SO4)(OH) and an unknown Fe-AsO4 species. All the hematite products contain - 1% SO4 which appears to be adsorbed on the nanometer-size hematite crystallites.IntroductionDissolved iron is a common impurity in most hydrometallurgical processing circuits and, generally, the iron must be eliminated prior to the subsequent recovery of the sought after metals. Simple neutralization of iron-rich solutions yields slurries which are difficult to thicken and filter. To address these concerns, the jarosite, goethite and hematite processes have been developed, and these technologies are able to reject the dissolved iron in a readily filterable form [1]. Despite its higher cost, the hematite process offers several potential advantages. Because hematite is an iron-rich, high-density compound, its formation would reduce the mass of residue and the size of a residue storage pond. Hematite is the thermodynamically stable form of iron under ambient conditions, and this stability would facilitate the impoundment of hematite precipitates. Furthermore, hematite has some market potential for cement manufacture and even for iron making [2]. In all the commercial hematite processes, the dissolved ferric ions are first reduced to the ferrous state. Subsequently, the pH of the solution is adjusted and the solution is then oxidized. The ferric ions gradually generated during solution oxidation hydrolyze and precipitate mostly as hematite, although commercial hematite products also contain trace or minor amounts of jarosite-type compounds. However, there are potential advantages in precipitating hematite directly from ferric ion solutions, as the reduction and subsequent oxidation of the iron are not required. Although the precipitation of hematite directly from relatively concentrated ferric sulphate solutions (up to 0.5 M Fe(SO4)is) was recently demonstrated [3], the behaviour of impurity species during hematite precipitation is largely unknown. To address this issue, systematic laboratory experiments were undertaken to ascertain the behaviour of a number of ""impurity"" species during the precipitation of hematite directly from ferric sulphate solutions at 225°C, and the results are presented in this paper."

Jan 1, 2012

By A. Robles

The main goal of the present work is to propose a viable alternative for selective arsenic elimination from copper smelter flue dust without the need of a global leaching scheme for all the individual components of the flue dust. Using this alternative, the inherent copper recovery problems are avoided. Arsenic precipitation is also considered for regenerating the solution and completing the process cycle. The experimental results for arsenic extraction and precipitation are satisfactory. Concentration of NaOH used was relatively low. The main reason for succeeding in high arsenic extraction and low NaOH consumption is due to the previous water washing of the flue dust. Water washing dissolves much of the iron and copper that are present in certain percentage as sulphate.

Jan 1, 1999

By Yuan Lu, Yiming Rong, Richard D. Sisson Jr

With the development of quench technology, there is a trend of using gas quench to replace liquid quench for less distortion and residual stress. The fundamental difference between the liquid and gas quench is the heat transfer coefficient, not only the values but also the shape of the curve as a function of temperature. The equivalent heat transfer coefficient for the liquid and gas quench is analyzed by simulations and experiments. Even it may result in the same hardness in the liquid and gas quench, the steel microstructure may be different because of the different cooling processes, and therefore other steel properties, such as toughness, may be different. The cooling process, microstructures and properties such as hardness and toughness should be examined when designing the liquid or gas quench processes.

Jan 1, 2015

By E. Allaine

Carbochlorination kinetics of pure MoO3, Nb2O5, Ta2O5 and V2O5, by Cl2+CO+N2 gas mixtures was investigated between 380 and 1000 °C. Standard free energy of carhochlorination reactions and phase stability diagrams of these refractory metal compounds were calculated. The influence of total gas flow rate, temperature, reactants partial pressures on the reactivity of these oxides were investigated. The apparent activation energies were found to be about 83, 75, 110 and 100 kJ/mole below 650°C for MoO3, Nb2O5, Ta2O5 and V2O5, respectively. Above this temperature, the Arrhenius plots exhibit a rate anomaly attributed to thermal decomposition of COCl2 and/or structural changes of these refractory metal oxides. The apparent reaction order of carbochlorination of these oxides with respect to Cl2+CO was determined. For these refractory metal oxides, the reaction rate was maximum for a Cl2/CO ratio of about 1 in the chlorinating gas mixture. Results of carbochlorination of these oxides are compared and discussed.

Jan 1, 1995

By K. Osseo-Asare

Aqueous stability diagrams (25°C) are presented for the systems M-H2O and M-Oxalate-H2O where M=Sm, Nd, Co, and Fe. With the aid of these diagrams (i.e., Eh-pH and log[Metal]- log[Oxalate]), the solution-chemical constraints on metal dissolution and precipitation are identified. By comparing the corresponding stability diagrams, conceptual flowsheets are developed for metal recovery from Sm-Co and Nd-Fe-B magnet scrap.

Jan 1, 1997

By Mahmood Alemrajabi

When LKAB processes their iron ores in northern Sweden, they generate apatite as a by-product. The apatite has been recovered by flotation and the concentrate contains about 0.4 wt% rare earth elements (REE). Both phosphate rock and REE are listed as critical raw materials for the European union. In the present study, the recovery of REE within the nitrophosphate process of fertilizer production has been studied. In the first stage, the REE are precipitated and isolated as a phosphate concentrate. For further purification and individual separation of REE by solvent extraction, removal of phosphorous from the concentrate to enhance the dissolution of REE in mild acidic solutions is essential. In this study, thermal treatment of the concentrate with sodium hydroxide at elevated temperatures followed by water leaching has been studied in order to separate the phosphorous and thereby facilitate dissolution of the REE. The results show that 95% of total phosphorous initially present in the REE phosphate concentrate is removed after thermal treatment with NaOH 1:1 mass ratio, at 400 °C.

By Lifeng Zhang, Zineb Benouahmane, Yaqiong Li

Experimental oxidation tests at high temperature (1000-1200 °C) on SiC samples have been respectively performed under wet and dry air atmosphere for different holding times. The thickness of thermally grown oxide was experimentally measured by DEKTAK Stylus Profilometry. The results showed that the oxidation rate was increased with temperature and holding time, corresponding to a passive oxidation regime which led to the formation of SiO2 layer. The sessile drop method was employed in order to measure the contact angles between Si and SiC at high temperature. Contact angle can be varied from 39.6° to 75.6° by controlling the atmosphere. The deoxidation of the oxide layer and infiltration of liquid silicon caused a decrease in the contact angle.

Jan 1, 2016

By P. M. Swash

The determination of the heavy minerals in beach sand samples is highly dependent on the preparation technique used. In this paper a simple reproducible method for the quantification of "recoverable" ilmenite, zircon, rutile and leucoxene by magnetic separation, is described. The procedure recommended yields information relevant to the metallurgical processing of the ore rather than to the total heavy minerals present in the samples. Finally the determination of mineral reserve estimations and grade assessments is greatly facilitated when this "mineral assay" method is employed. An assortment of other mineralogical methods are described including SEM, EMPA, XRD, XRF, Image analysis, Mossbauer. clerici and perm roll separations. The methods are briefly examined and the practical information that can be gained by using such techniques are reviewed. Experience has shown that an understanding of the relationship between the physical and chemical properties of the heavy minerals can contribute to the prediction of mineral particle behaviour. Such information may ultimately help reduce the prospect evaluation period and minimise expenditure on metallurgical testwork.

Jan 1, 1991

Iron(II), sulphur dioxide and sugars such as lactose are potential reducing agents for manganese dioxide to produce manganese(II) for subsequent hydrometallurgical treatment. The leaching of limonitic laterite and manganiferrous ores with sulphur dioxide produces iron(II) which in turn can catalyse the leaching of manganese dioxide in acid media. This paper presents a critical analysis of the kinetics of reductive dissolution of synthetic manganese dioxide and manganese ore to compare and contrast the effect of sulphur dioxide and iron(II) in acid media containing sulphate or perchlorate anions. Both one-electron and two-electron mechanisms are considered in the case of sulphur dioxide. The current knowledge on chemical speciation is used to construct an Eh-pH diagram to show the effect of complexation of Mn(II), Fe(II) and Fe(III) with sulphate. Heterogeneous and electrochemical reaction kinetic models are combined to propose reaction mechanisms which rationalize the dissolution kinetics.

Jan 1, 2003

By B. J. Beaudry

Intermetallic compounds are frequently required in the form of thin sheets for magnetic refrigeration and other applications. Progress has been made in the preparation of thin sheets of brittle gadolinium intermetallic compounds by hot rolling of sheathed billets. The effect of fabrication procedures on the Curie temperature of GdPd and its heat capacity at low temperatures has been studied.

Jan 1, 1989

By Wilky Desrosin, Alicia E. Ares, Carlos E. Schvezov

"In the present research the horizontal directional solidification Zn-Sn alloys (Zn-4wt. %Sn, Zn- 6wt. %Sn, Zn-10wt.%Sn and Zn-30wt.%Sn) was carried out by extracting heat in two opposite directions. For this purpose, ceramic molds, a muffie, a horizontal furnace with two heat extraction systems at the ends, a measurement, acquisition and recording temperature system, eight K-type thermocouples and an electronic recorder were used. The main parameters involved in the columnar-to-equiaxed transition, CET, were: the moment of start and end of solidification at each position under consideration, cooling rates, the average temperature gradients and critical temperature gradients at the CET, the average speed of liquid and solid interphases left and right, advancing in opposite directions. Also, solidification kinetics was found to be different between horizontal solidification two-way heat extractions, with preliminary results of the vertical unidirectional solidification. In the solidification experiments, the velocity and accelerations of the liquidus and solidus interphases usually occurs at the end solidification zone of the samples.IntroductionSolidification of metal alloys, which starts in the external equiaxed region (chill), results in two basic types of structures in a single solidified alloy sample: columnar and equiaxed. The presence of both structures indicates the occurrence of the colunmar-to-equiaxed transition phenomenon[!].Studying the colunmar-to-equiaxed transition, CET, is of great technological interest for the evaluation and design of the mechanical properties of the solidification products. To this end it is necessary to understand the mechanisms by which it occurs. As found in previous studies [2-5], the CET occurs by competition between columnar and equiaxed growth. Mainly is controlled by the parameters of casting, such as the alloy composition, the density of the present nuclei in the liquid, the cooling capacity of the metal I mold, and the degree of convection in the liquid [7-10]."

Jan 1, 2014