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By A. McLean, Y. Uchida, M. Iwase, M. Myochin, K. Wiikimoto

"Phase diagrams of FeO-containing ternary systems could be derived from experimental data for the activities of FeO. The systems investigated are CaO-CaF2-FeO, SrO-SrF2-FeO; BaO-BaF2-FeO, CaO-CaCl2-FeO, SrO-SrC12-FeO, BaO-BaC12-FeO, CaO-A12O3-FeO and BaO-SiO2-FeO.IntroductionThe importance of phase diagram cannot be overemphasized. In a book, ""Alloy Phase Equilibria""[l], the author, Professor A Prince, states, ""A metallurgist has been defined as a person who thinks in terms of phase diagram"". Whether one accepts this statement or not, it is self-evident that an ability to interpret phase equilibria is essential to the professional metallurgists.The physical chemistry studies of iron and steelmaking process often require phase diagrams of FeO-containing slags. Iso-thermal section of the phase· diagrams of such systems can be derived from experimental data for chemical potentials of FeO. Due to the recent developments in the area of solid state electrochemistry, rapid determinations of the FeO activities have become possible. The present paper is aimed at documenting the derivation of the phase diagrams of FeO containing slags.Experimental AspectsAn electrochemical method incorporating stabilized zirconia can be used for the measurements of the activities of FeO in various slags and fluxes[2]. For the details of the experimental technique, reference should be made to reference 2"

Jan 1, 2000

By R. J. McClincy

The potential techniques for the direct smelting of copper sulfide concentrates to blister copper were evaluated from the standpoint of commercial application. Many existing smelters are adaptable to direct smelting practice but only with improved control of metallurgical performance. Modified and innovative procedures for slag cleaning and metal refining, prerequisites to direct smelting, are presented and discussed. The ability to smelt directly to blister copper using existing equipment and eliminating the need to convert matte offers ,significant advantages to traditional smelting practice from the viewpoint of cost, 'S02 control, and process simplicity.

Jan 1, 1983

By Boxun Lu, Juan Wei, Kun Chen, Wanlin Wang, Lejun Zhou

"Slag system is an indispensable part during the continuous casting process, and playing various important roles like absorbing inclusions, modifying heat transfer rate, preventing oxidation of molten steel, etc. to ensure the smooth process and excellent slab quality. However most slags contains more than 8% fluorides which tend to introduce a series of environmental and health problems. This study involves the research of the removal of fluorine through the chemical composition optimization. Through the studies of CCT, DHTT, XRD and SEM, it has been successfully founded that the crystalline phase of Ca11Si4B2O22 discovered in this study shows very similar crystallization property as Cuspidine (Ca4Si2O7F2), which is the most important crystalline phase in the current fluorine bearing slags. Moreover, the optimized free/low fluorine slag shows the opportunity to replace conventional high-fluorine mold slag for casting medium carbon steels that is regarded as the bottleneck of green slag development for continuous casting.IntroductionMold flux has been widely used in continuous casting to control heat transfer, lubricate the strand, absorb inclusions, provide insulation and prevent oxidation of the molten steel[1-3]. It usually contains fluorides, like CaF2, NaF etc., which are used to control the viscosity and solidification temperature of mold fluxes [4-5]. However, the presence of fluoride leads to corrosion of equipment, serious environmental pollution (toxic volatiles and water pollution), and high processing cost of cooling water[6-7]. Therefore, the study of low or free fluorine mold flux is of interest and attracts worldwide attention.S. Y. Choi et al. [4] used B2O3 as a substitute for cuspidine in steel B2PB2) however, B2O3 content was extremely high (up to 30 w%). Other studies have investigated F-free mold flux by adding or optimizing components as MgO, Li2O, B2O3 et al[8-11]. However, most of these focused on the melting and viscosity issues or for low or ultra-low carbon steels, where crystallization tendency is not significantly strong. Very few studies regarding to the development of low/free Fluorine mold flux for casting medium carbon (MC) steels have been conducted, due to the difficulty of the crystallization and heat transfer control without the formation of cuspidine."

Jan 1, 2014

By C. H. Tsau

The intermetallic compounds of Ni-25Al-xFe, x is 20-40 at.%, were prepared by arc melting and drop casting into ingots, and were rapidly solidified into ribbons by melt spinning. The microstructure evolution of these alloys with varied Fe content were examined by the x-ray diffraction, optical microscope, scanning electron microscopy and transmission electron microscopy. The results reveal that two phases, {y'} and {B} phases, are existing in the alloys with low Fe content, and the microstructure changes from the mixture of y' and {B} phases to a single 0' phase when the Fe-content reaches to 40 at.%. Also, the formation of y' phase will be suppressed by rapidly solidified process. For annealing both of the melt-spun and the cast specimens, a disorder 0 phase was revealed in both of the ribbon and the cast ingot of Ni-Al-Fe alloys with higher Fe content. In addition, increasing the increment of iron which substituting nickel in this alloys results in increasing the lattice parameter of both {y'} and{B} phases.

Jan 1, 1992

By Jack S. McPartland

The recent developments on the concentration and recovery of gold from leached gold thiosulfate solutions by solvent extraction, reduction-precipitation, and electrochemical deposition are reviewed in this paper. Alkyl phosphorus esters have been found to extract gold only in alkaline thiosulfate solutions, The recovery of gold increases with thiosulfate concentration in the aqueous phase and with alkyl phosphorus esters concentration in the organic phase with aliphatic hydrocarbon diluents. The addition of ammonia improves the extraction. The extraction of gold with amines in either aliphatic or aromatic diluent decreased in the following order: primary>secondary>tertiary amines. Increase in the extractant concentration at high pH increased the extraction of gold. At pH < 9, the primary amine, RR&apos;CHNH2 with 1&apos;9-23 carbon atoms is the main extractant with TBP as the synergistic reagent and at pH >9, the primary amine shows a synergistic effect on the extraction of gold&apos; with TBP. TheAu(I) ions in thiosulfate solution are reduced by sodium borohydride (SBH) to metallic gold, with particles in the sub micron range, At an SBH/ Au ratio of 6.25, pH = 6, and at room temperature, the I e ppm Au(I) in a solution of ] 0 gil thiosulfate was completely reduced to metallic gold in about 60 minutes.

Jan 1, 1999

By Tapani Järvinen

Non-ferrous metals and metals in general are considered as being non-renewable natural resources. Metals are needed because of their excellent and irreplaceable properties. The consumption of metals, with the exception of carbon steel, is steadily growing by 1-3 % annually, and that of stainless steel as much as 3-6 %. This is a general trend, which is periodically disturbed by cyclical variations. In recent years so-called "New Economy" has become prominent in the public media and the market value of the traditional industry has been well below its real value and importance. Nevertheless, the modem society requires metals today and also in the future, and the companies using the most modern technology in a responsible way and innovative solutions not only in technology, but also in everything they do will survive. This paper describes the role of Europe as a producer of primary base metals and as a supplier of technologies in the base metals industry. It concentrates on the development and commercialization of technologies and project implementation in the metallurgical industry. As one example ofa European approach to these matters the paper presents Outokumpu&apos;s response to the future challenges in the base metals industry. Outokumpu Oyj is one of the leading metals and technology companies in the world of stainless steel, copper, zinc, and sales of technology in metals and minerals businesses. Outokumpu applies its knowledge of metals and processing to generate value for its customers and shareholder. Everything we do, we do in an economically, environmentally and socially responsible way.

Jan 1, 2003

By S. A. Platias

Large amounts of dunile tailings can be recycled for olivine produdion from the existing beneficiation adivity of chromite ore in northern Greece. This olivine production aims at the preparation of a material suitable for the substitution of the environmental hazardous quartz sand in the foundries of Europe In smelting of chromite ore the losses that occur ore usually of the order of 6-8% Cr that report in the slag. Most of this is in the form of oxides that cannot be recovered, but usually 30-35% is in the form of FeCr alloy that can be recovered by gravity methods. About 90% of the produced slag is sold for road construdion after crushing to a desired grain size. Finally, recycling of chromites sludges from the ferrochrome produdion plant, through the preparation of pellets, improved the total chromite yield by 2%.

Jan 1, 1996

By Fumitaka Tsukihashi

Increasing amounts of steel scrap are being used as resources for steelmaking. Therefore, there has been a growing interest in the removal of harmful tramp elements such as antimony, zinc, tin, arsenic, bismuth, lead and copper from the molten steel. The problem that should be solved is the economic removal treatment of residual tramp elements in the steelmaking processes and the production of high quality steel by reducing the effect of the contaminated tramp elements and satisfying the environmental regulations. In this paper, the available thermodynamic data of the residual tramp elements in the molten steel arc summarized and the possibility of the removal of residual tramp elements from the molten steel is thermodynamically estimated.

Jan 1, 2003

By D. Bruce Wilson

The reaction of oxygen and solid aluminum produces the well-known surface coating of aluminum oxide, Al2O3. Thermodynamic properties and kinetic mechanisms of this reaction are extensively documented. Less well-defined are the corresponding liquid phase reaction and reactions which would be characterized. as &apos;burning&apos; of aluminum. This paper reviews the solid aluminum-oxygen reaction as a foundation for discussing the flammability of aluminum in oxygen-enriched atmospheres. Appropriate thermodYDan3ic analysis and kinetic reaction mechanisms are developed. Available models of aluminum burning are reviewed and evaluated, The appropriate information for design of engineering applications of aluminum in oxygen atmospheres? is summarized.

Jan 1, 1996

By Run-sheng xu, Hai-yang WANG, Di ZHAO, Teng-fei SONG, Jian-Liang Zhang

This paper was mainly focused on the different semi-cokes and charcoal which could be new fuels for blast furnace injection. Through the comparative study with bituminous coal and anthracite coal, the properties of semi-cokes and charcoal were presented in this research. 10 indexes of different fuels were obtained by different standard experiment, including proximate analysis, ultimate analysis, igniting point, explosivity, transportation characteristic, ash properties, grindability, calorific value, combustibility and reactivity with CO2. According to the data analysis, it provided a theoretical basis for rational utilization of various blast furnace fuels, and helped to broaden the scope of the blast furnace injection fuels. This research could contribute to energy conservation, emissions reduction, and sustainable development of iron and steel enterprises.

Jan 1, 2015

A study was undertaken to remove the Se from waste solutions using a raw form of the biomass called Iota Chips derived from the seaweed, Eucheuma spinosum. Removal of Se from solutions was investigated as a function of time, pH, conc. of Se in solution (0.1 to 100 ppm) and lota Chips to liquid ratios of 10-2 to 10-5. For solutions containing initial conc. of 0.1 ppm Se, with the addition of Iota Chips at a solid to liquid ratio of 10-3, the Se conc. decreased to 0.03 ppm in about 3 hours. Iota Chips absorption capacity to the Se and its application to the treatment of the metallurgical processing effluents are discussed.

Jan 1, 1992

By Alessandro Blasi, Massimo Morgana, Corradino Sposato, Pietro Garzone, Giuseppe Devincenzis

The rare earth elements are essential for a diverse and expanding array of high-technology applications, which constitute an important part of the industrial economy of the 21st century. As a matter of fact, rare earth has been listed in the category of strategic elements in many countries becoming a core business for international research. Experimental tests have been carried out on a bench scale battery of mixer settler composed of 24 stages, each one with a volume of 150 ml. These trials have been performed at room temperature checked by a micro-climatic control system. The battery was setted in two sections: extraction and scrubbing section. Rare earths concentrations were obtained by ICP-OES analysis made on aqueous phase and on the stripped from organic phase. We obtained a complete separation of light rare earth (La, Ce, Pr, Nd) in two sub-groups: La/Ce and Pr/Nd.

Jan 1, 2014

By V. Ramachandran

In view of the increasing environmental regulations that have been promulgated in the last 30 years, non-ferrous smelters and refineries have learnt to handle effectively the process waste streams that need to be bled from the system for impurities&apos; control The cations of concern are copper, lead, zinc, cadmium, mercury, thallium, nickel, silver, sodium and potassium. Anionic species of arsenic and selenium also need to be addressed, Sulfates and chlorides-not a major concern at present-have come under scrutiny in the recent past. The current paper reviews several treatment options with reference to a) types of waste streams processed b )process chemistry c)discharge options and recovery of treated water and d) sludge disposal The long term goal of any smelter and/lor refinery should be to achieve zero liquid discharge from the plant. Methods to obtain zero discharge are discussed.

Jan 1, 2003

By Ann M. Hagni

Microscopic and sub-microscopic gold commonly occurs in the sulfides pyrite (FeS2) and arsenopyrite (FeAsS). To recover refractory gold from pyrite and arsenopyrite, these sulfides are roasted to create porosity and permeability prior to cyanide leaching. A new technique of adding Ca(OH)2 and roasting. lime roasting. is being tested for retention of contaminant sulfur and arsenic and effectiveness of gold extraction. The lime roasting of pyrite at 500°C contains anhydrite (CaS04). oldhamite (CaS). calcium sulfite (CaS03). hematite (Fe2O:J), magnetite (Fe304). and minor amounts of pyrrhotite (Fe1.xS) and pyrite. At 600°C. 650°C and 700°C. the main constituents are anhydrite. oldhamite. and hematite. At 750°C. 800°C. and 850°C. anhydrite and hematite are the predominant phases with minor oldhamite. The roasted arsenopyrite at 450°C contains arsenic sulfides. calcium sulfite. hematite. and minor oldhamite. magnetite. and pyrrhotite. At 650°C. 700°C, 750°C. and 800°C, anhydrite, oldhamite. arsenic sulfides, and hematite are present. At 850°C. the same minerals are present with only minor oldhamite. The textures indicate excellent porosity and permeability at high temperatures. At lower temperatures, rims of low porosity and permeability surround many of the pyrite and arsenopyrite particles, and the complete oxidation process from pyrite to pyrrhotite to magnetite to hematite can be observed in individual particles. Additional process mineralogy techniques employed in this study are electron spectroscopy for chemical analysis (ESCA) and cathodoluminescence microscopy (CIM) in the determination of the calcium-sulfur-oxygen phases. Automated scanning electron microscopy-energy dispersive spectroscopy was utilized to analyze particles for gold content. Reflected light microscopy (RIM) revealed arsenopyrite and pyrite encapsulated in quartz particles of the gold-bearing concentrate, gold roast calcine, and cyanide leach residue.

Jan 1, 1991

By Chunyang Guan, Jilai Xue, Jun Zhu, Qiaochu Liu

"Al-Sc Alloys have showed many advanced properties for a wide range of industrial application, which is usually produced using thermal reduction process. This work is aimed to develop an electrochemical process to make Al-Sc alloy using industrial Hall aluminum reduction cells. The experiments have been carried out in a lab cell where NaF/AlF3-Al2O3-LiF as electrolyte, Sc2O3 as raw material, and liquid aluminum as cathode were used at operating temperature of 950 °C. The resulting Al contained 0.2 - 0.5 wt.% Sc that is the common range in its content for advanced applications. However, a small fraction of Sc was found from thermal reduction at Al melts interface. SEM-EDS and ICP-AES analysis showed a uniformed distribution of Sc at varying locations of the Al-Sc alloy sample. In addition, a higher Sc content in Al-Sc alloy can be obtained with introducing ultrasound through the cathode than that without it.IntroductionIn recent years, scandium has been investigated as an alloying element for aluminum alloys. With addition of a small amount of Sc, Al alloys can improve the strength, weld ability, resistance to re-crystallization and corrosion resistance [1-3]. Due to their advanced properties and potential applications, the demand for Al-Sc alloys will increase in the future. However, the difficulties in reduction technologies and the high costs in production process may limit their expansion in application areas.The current major method of producing Al-Sc alloys is to mix Sc into Al by melting Al-Sc master alloy. This alloying process has several technical problems, such as easy segregating and heavy burning loss, etc. The price of Sc metal or starting material is also high, so the mixing process is an expensive alloying method. Molten salt electrolysis is alternative method to prepare RE metal and RE alloys [4, 5]. It also can reduce the segregation of alloying elements. Sc2O3 is an ideal material as raw material with low price and decomposition voltage. Some work has proved that Al-Sc alloys can be obtained by electrolysis Sc2O3 directly in cryolite [6-8], or CaCl2 molten salt [9]."

Jan 1, 2012

By Gaifeng Xue, Xiaohong Xu, Meng Liu, Yijie Song, Guotao Xu, Jixiong Liu

BN (Boron Nitride) based composites were prepared with hot-pressing by using h-BN as main material in ceramic preparation process. The relative density, bending strength, vickers’ hardness, thermal shock resistance, thermal expansion coefficient, thermal conductivity, phase composition and microstructure were tested and analyzed by using modern testing technology. The results indicate that the best formula is B, the relative density is 97%, the bending strength is 260 MPa, the hardness is HV5 343kg/mm2, the thermal expansion coefficient is 2.8×10-6℃-1, the thermal conductivity is 22 W/(m.K) and have no crack after thermal shock for 20 times by water cool. XRD analysis indicates that the main phase compositions are h-BN, β-Si3N4 and sialon. SEM studies show that the grains wrapped up by solid solution.

Jan 1, 2015

By Saskia Duyvesteyn

For many applications in hydrometallurgy and water treatment it would be advantageous to use ion-exchange resins in stirred reactors. However, attrition of the resin may lead to significant losses of both resin and metal values and prevent water quality goals from being reached. We have studied the recovery of fine resin particles by froth flotation, using the model copper - Dow XFS4195 chelating resin system. As the functional group on the resin is a bis-picolylamine, the resin should be amenable to flotation by anionic collectors, such as sodium dodecylsulfate and sodium dodecylsulfonate. The kinetics of copper loading from dilute aqueous solutions in an agitated vessel were studied as a function of copper concentration, pH and resin bead size. The flotation of unloaded resin was investigated for different types of collector, collector concentration, conditioning time, and resin bead size. Potential applications are discussed.

Jan 1, 1995

By Takeo Fujino, Nobuaki Sato, Junichi Hasegawa, Masato Nakazawa, Kohta Yamada

"Tantalum oxide thin films were deposited on quartz substrates by laser ablation of Ta2O5 target using Nd:YAG pulse laser. Deposition-was observed when a laser light energy higher than 200 mJ and its repetition rate higher than 3 Hz. A thin film of 0.1 µm thickness was obtained by the ablation using a laser light of 300 mJ and 6 Hz for 2 sec. The thickness of the film increased with increasing energy, repetition rate and irradiation time of laser. By the SEM observation, it was found that many island-like particles were deposited on quartz substrate forming a thin film. The obtained thin film, which was identified as ? Ta-O by X-ray diffraction, was oxidized to Ta2O5 by the heat treatment in air at I273 K for 3 h.IntroductionTransition metal oxides have a potential to show special characteristics in electrical, magnetic and/or optical properties. When such compounds are fabricated in the form of thin film, the special properties would be improved or new characters would appear in comparison with bulk materials. Tantalum penta-oxide is widely used as a capacitor since Ta2O5 shows high dielectric constants up to high temperatures. The tantalum solid capacitor has been fabricated by the electrical oxidation of sintered Ta metal cylinder followed by MnO2 film coating. However, further improvements, reduction and layered structure formation, are required for compacting the devices. The layered structure of thin films would be applicable for the above requirements. The formation ofTa2O5 film by low pressure CVD1), photo CVD2) and magnetron sputtering3l were reported. The laser ablation -method is one of the most convenient techniques for the deposition of thin films from their compounds, such as oxides. Formation of Ta2O5 film by pulse laser deposition (PLD) method using ArF excimer4), Nd:YAG (533nm)5) and TEA CO2 6 lasers was reported. In these PLD studies, ablation was carried out in relatively high oxygen pressures resulting in formation of Ta2O 5 film. In this paper, the deposition of tantalum oxide thin film by the laser ablation of Ta2O 5 using Nd:YAG pulse laser was examined at a viliety oxygen pressures ranging from 10-8 to 10 Torr. The morphology of the films was also investigated in relation with substrate temperature and oxygen pressure."

Jan 1, 2000

By John E. Litz

Metal-bearing flue dusts are produced by some ferrous and non-ferrous industries. Many dusts are being or can be treated for recovery of metal values. Operating and proposed flowsheets for the most common dusts are reviewed. Advantages, disadvantages, product marketability, and cost implications are discussed for each flowsheet.

Jan 1, 1992

By Sylwia Zymankowska-Kumon, Rafal Danko, Mariusz Holtzer, Artur Bobrowski, Michal Kubecki

"Moulding sands with furan resin constitute constantly growing part in technologies of producing castings from iron alloys. Due to the presence of harmful substances in resins such as furfuryl alcohol, phenol and formaldehyde, using those mould sands may be hazardous to the natural environment and workers. The general assessment of harmfulness of sands used for molds and cores encompasses 2 basic points: emission of hazardous substances during processes of preparing sands, pouring mold with liquid metals (high temperatures), cooling and shaking-out; possibility of washing out hazardous substances from used sands to the environment, during storage or economic use outside foundries. We present the results of research on the assessment of harmfulness of mould sands with furan resin in the scope of the above points. The research was conducted according to the original method prepared by the authors, which has been used for years in cooperation with various foundries (Poland, abroad).IntroductionSands are used by the foundry industry to create metalcasting moulds, where the individual sand grains are typically bound using bentonite clay and carbonaceous additives or resins. During the casting process, the moulds can be exposed to temperatures as high as 1500°C depending upon the metal being poured. The molten metal causes thermal decomposition of carbonaceous additives or resins, which results in the formation of potentially hazardous organics that are emitted to the atmosphere and condense in the moulding sand [1]. The moulding sands are reclaimed within the foundry, but part of them are eventually discarded in landfills, because it is not longer suitable to make metalcasting molds [2, 3]."

Jan 1, 2013