Search Documents

By I. D. Reznik

On blowing nickel matte in a converter without quartz, first the oxidation of metallic iron and a part of FeS occurs without evolving sulfur dioxide, the formed FeO dissolves in a sulphide smelt and form a homogeneous oxysulphide smelt. On further increasing the FeO content, the oxysulphide separates into 2 layers. Based on the laboratory investigation of FeO-(FeS+Fe°) - (Ni3S2+Ni°) ternary phase diagram we have identified the separation region at 1250°C. The boundaries of the separation region have the form of an arc and the composition of the separated oxysulphide layers is defined by the canodes. In the nickel or copper-nickel matte - silicacalcium oxide slag system at 1250°C three layers, namely sulphide, oxysulphide, and slag may be formed. A high slag basicity due to the presence of CaO can serve to enhance the activity of FeO; a low nickel content in the matte corresponds to a high concentration of FeS therein; FeO from slag and FeS from the matte form a homogeneous FeO-FeS solution, i.e. an oxysulphide layer. The investigation on the "Camebaks" apparatus and by the nuclear gamma-ray resonance spectroscopy method of the phase composition in a slowly cooled oxysulphide layer has shown the presence of four phases: wustite, troilite, ferronickel grains, and calcium oxide-silica inclusions. Knowledge of regularities in the oxysulphides formation makes it possible to use them in pyrometallurgy of nickel and cobalt or preventing their formation.

Jan 1, 1997

By B. Rourke, O&apos

Copper Refineries Ltd. (CRL), Townsville is Australia's largest producer and exporter of refined copper cathode. This status has been maintained by the implementation of a significant capital works program that increased the production capacity to 270,000 t/y by June 1999. In 1979, CRL was the first in the world to commission the ISA Process Technology which has now been marketed to 47 licensees worldwide. The new tankhouse design has focused particular attention on customer requirements, operational improvements, materials handling and equipment modernisation. Equipment which has been upgraded includes cranes, anode preparation, cathode stripping and scrap washing machines along with the total replacement of the electrolyte and electrical reticulation systems. Side stream electrolyte filtration has been introduced. Improvements to electrode alignment afforded by the conversion to polymer concrete cells, precise electrode location, and the upgrade of the electrode handling machines will ensure that CRL. continues to be one of the world's major quality copper cathode producers.

Jan 1, 1999

By Guohui Zheng

The ever increasing quantities of solid wastes generated by various industries are at the source of the growing need for proper waste disposal methods. Thermal treatment of combustible wastes is a proven technology which permits the reduction of hazardous material having to be landfilled. However, this method is not universally applicable to waste disposal. For example, the transferal of heavy toxic metals into the thermal remediation products is a major issue of public concern. This paper focuses on the analysis of morphology changes from solid sludge to ash which is a product of the sludge combustion. The morphological parameters analyzed were particle size and external surface. They were determined using Jeol 840 Super Probe. The experiments were conducted in a computer-controlled high-temperature combustion system consisting of the thermogravimetric furnace coupled with Fourier transform infrared spectrometer (TGA-FTIR). Sludge particles were made of complex fibers trapped in the aluminosilicate matrix. At low temperatures, up to 680 K, the solid residue looked similar to the initial sludge. Between 680 K and 1180 K the sludge underwent intensive burning and steadily changed into powdered ash. At the temperature of 1050 K the ash was composed of separate, flat flakes with sizes ranging from 5 to 20 um. At 1470 K the flakes aggregated into large particles. The surface observed at 1670 K was a mixture of mullite crystals. Such structure could result from the solidification of the ash material after its melting. Morphological changes influenced the distribution of metals in the solid residue. For example, Cr was concentrated in small aggregates. Such distribution should allow for recovery of valuable metals from the solid waste residue.

Jan 1, 1996

By Edwin Adoyi Ali, Zainab Shehu Aliyu, Adele Dzikwi Garkida, Muhammad Dauda

Feldspar from Matari, Nigeria was analyzed using SEM, XRD and XRF techniques for microstructural analysis, mineral phase analysis and chemical composition analysis respectively. Qualitative and quantitative XRD analyses revealed the presence of microcline 59.6%, albite 34.7% and quartz 5.71%. The XRF results showed that the feldspar contains 67.32% SiO2, 17.54% Al2O3, 11.33% K2O, 2.75% Na2O, 0.12% CaO, 0.01% MgO, 0.02% MnO2, 0.10% Fe2O3, 0.00% Ti2O, etc and 0.14% LOI. SEM/EDX analysis shows the presence of microcline feldspar as the dominant phase, exhibiting lamellar twinning. The XRD has also revealed that potash has the highest peak, indicating its high concentration. The 0.10% Fe2O3 present is within the permissible level (0.1-0.3%) for glass making and also within the potash feldspar specifications (0.17%). The Matari feldspar is a microcline type, rich in potash, alumina and silica, enabling it meet the standard specifications for alumino-silicate glass.

Jan 1, 2015

By N. M. S. Balbinot, A. L. Rodríguez, C. M. Mahlmann, R. de C. de S. Schneider

The use of sunflower oil co-products it was studied for production thermoplastic composites. Thermoplastic composites have been processed in polyethylene matrices of virgin linear low density polyethylene (LLDP) or recycled. Samples have been formulated with 10% mass fraction of sunflower bran, seed coat and mixture of bran and seed coat. The material characterization has been achieved by mechanical tensile test and Shore D hardness and by density physical testing. The results have demonstrated better properties to thermoplastic composites with sunflower seed coat.

Jan 1, 2008

By Laurent Cohen

Since the 1970s, Solvent Extraction (SX) in hydrometallurgical processes has been a key enabling technology in the production of high-purity metals. Examples include copper, rare earth oxides, uranium, cobalt and nickel. Notwithstanding incremental improvements in extractant formulations, few breakthroughs can be recounted in this industry outside of the initial amine-, oxime- or phosphine-based reagent chemistries. However, the advent of lithium-ion batteries and their stringent requirements for critical materials (lithium, cobalt and nickel) offer new challenges and opportunities for SX. Solvay recently introduced a new extractant for lithium, CYANEX® 936, and developed unique modeling software capabilities in cobalt/nickel separation using CYANEX® 272, zinc SX using DEHPA® and rare earth separations using CYANEX® 572. This paper discusses trends in SX and provides insight on processing of critical materials essential to energy sources. It also summarizes the technical and economic benefits based on extractant selection and advances in modeling.

By Xi Dai

The LiFe1-xNixPO4(x=0, 0.05, 0.10) cathode materials for Li-ion battery were synthesized with Fe1xNixC2O4?2H2O(x=0, 0.05, 0.10) as Fe sources by high temperature solid-state reaction method. The Fe1xNixC2O4?2H2O(x=0, 0.05, 0.10) materials were produced by liquid co-precipitation method and crystal structure and morphology of cathode materials were characterized by X-ray diffraction and scanning electron microscopy. The composition contents and charge-discharge performances were measured by chemistry analysis and charge-discharge apparatus. The XRD patterns showed that LiFe1-xNixPO4(x=0, 0.05, 0.10) cathode material samples were well-crystallized homogeneous olivine-type phase, with only tiny trivalent iron impurities according to chemistry analysis results. Charge-discharge test showed that cathode materials possessed excellent charge/discharge capacities, about 150mAh/g at 0.1C rate and more than 120mAh/g at 0.4C rate. The polarization of cathode in charge-discharge process can be restrained effectively, for the potential offset between oxidative peak and reductive peak of doped LiFePO4 material was only 0.079V, lower than pure LiFePO4 markedly.

Jan 1, 2006

By S. Raghavan

The thermodynamic activities of MgO in the solid solutions that can exist in the system NiO-Mg0-Zn0 are determined by measuring the EMF of the cell: O2 (g), Pt / MgO, MgF2 // MgF2 // x MgO + yNiO + (1-x-y)ZnO / Pt, O2 (g) / MgF2 in the temperature range 1190-1237 K. Equilibrium phases were prepared along the quasi- binary lines MgO/NiO = 0.1765,0.3333, 1.0,3.0 and 5.667 with the ZnO contents being 0.1, 0.2, 0.25, 0.35, 0.5, 0.75 and 0.9. The crystal structures of the phases were identified by X-ray diffraction. Results obtained so far show that a single phase MgO-rich cubic solid solution exists upto 0.2 ZnO content and for compositions above 0.25 ZnO, a second ZnO rich wurtzite phase forms in addition. Activity measurements show that for low MgO and ZnO contents, the MgO activities exhibit ideal to slight positive deviation from ideality and at higher MgO contents, a negative deviation is shown. Further studies are in progress.

Jan 1, 1993

By P. Mercille, M. F. Nasmyth, J. G. Cooper

The turn of the century sees considerable activity in the zinc industry for the replacement or expansion of existing cellhouses, and the building of new cellhouses as part of new zinc projects. Aside from the cellhouse technology itself, numerous engineering and construction issues play a major role in the success of a project for replacing or building new cellhouses. The purpose of this paper is to bring to light and to address the engineering and construction factors which go beyond the selection of a cellhouse technology and which remain of key importance in implementing such projects. In addition, some implications of these factors for project costs will be illustrated.

Jan 1, 2000

By R. R. Odle

A laboratory and pilot-scale investigation of direct smelting of copper concentrates was conducted to determine the effect of concentrate analysis and the degree of roasting on the yield and quality of copper produced in a subsequent smelting step. A stoichiometric :mOdel of direct smelting is presented which predicts the? quantity of copper; slag, and white metal' prOduced'and the distribution of copper in these phases as a function? of the concentrate '(calcine) analysis.

Jan 1, 1983

By Ulrich Kerney

In 1996, bath smelting technology for lead recovery from concentrates and secondary materials was introduced in Nordenham to replace the common sinter plant/shaft furnace operation. Since start-up, a continuous improvement of equipment and operation lead to a steady increase of capacity and plant availability. The decision to skip the reduction stage for slag treatment now allows the treatment of 200000 t/a feed materials with a secondary fraction of up to 70 %. The main feed source for the furnace is automotive battery recycling, which offers oxide paste and metallics to be molten under oxidizing conditions in the lance fired furnace. The lead bullion is transferred to the refinery, where copper, silver and other impurities are removed. Silver is recovered as doré quality. All loopings are recycled to the BSF. Inert feed material is collected in a so-called lead concentrate of metallurgical origin, the primary slag, which is sold. It is rather a valuable feed material for further processing than a slag The off-gas is cooled in a flux-flow system, entering then an electrostatic dust precipitator. Having passed a further washing and cooling system, SO2 is oxidized and collected and sold as concentrated sulphuric acid. The presentation will cover a review of the start-up phase, the development of significant production parameters over the last years and actual production routes and figures. A comparison of environmental data between new and old applied technology is made.

Jan 1, 2006

By E. Burgos Cruz

The behaviour of S, N and P during refining of Fe-18 wt%Cr-10 wt%Ni with calcium carbide was investigated. The effects of the initial contents of C and N in the metal phase, as well as the supply method of calcium carbide to the melt on the removal degrees of S and P were evaluated. Heats were carried out at 1873K, in MgO crucibles, using a laboratory induction furnace. It was observed that simultaneously with S and P, N and O have also participated in the reactions. It seems that, in fact, O governs the behaviour of the other elements dissolved in the melt and that N is had to the removal of P with calcium carbide. It was also noticed that high C content in the metal phase have not altered the dephosphorization and desuffirization degrees, but that the supply of calcium carbide done by injection led to a lower dephosphorization degree than the one obtained by dumping it.

Jan 1, 1995

By K. S. Han, M. Yoshimuura, H. Fujita, Y. Sato, S. W. Song

"Film of LlCoO2 as cathode material for rechargeable lithium microbatteries has been fabricated on the platinum metal substrate by electrochemical-hydrothermal method in concentrated LiOH solution at 200 °C as Soft Solution-Processing. The film fabrication has been understood in terms of dissolution of cobalt metal powders and subsequent oxidative deposition on the substrate. The film structure was characterized using scanning electron microscope, X-ray diffraction analysis; X-ray photoelectron spectroscopy and micro-Raman spectroscopy.IntroductionRapid growth of wireless communications and emerging integrated optoelectronic circuits caused the miniaturization· cif electronic devices, thus the demand for high energy density microbatteries as a power source for the microelectronics increases. In this regard, all solid-state lithium microbatteries including LiCoO2 and LlMn2O 4 [l-4], the most promising intercalation cathode material, have been developed. However, major difficulty of .fabrication of a lithium microbattery arose from the preparation of cathode film, according to a· recent report on Rare Metal News [5]. Although many attempts have been made to deposit the cathode films, all those methods are mostly chemical vapor deposiiton (CVD), various evaporation, sputtering techniques and spray pyrolysis. These methods require preparation of bulk cathode materials cir its precursor, then deposition with complicated instruments including high· vacuum system, and even postsynthesis annealing to obtain desire electrochemical 'properties. It is clear that all of these techniques are neither economic nor environmentally friendly. Compared to those methods, film form.ation from an aqueous solution is thought to be simpler and more economical, and requires much· less energy consumption. Our .group has demonstrated the utility of Soft SolutionProcessing [6,7], which is defined as environmentally friendly processing using (aqueous) solutions, to produce films of a variety of functional solid materials. According to the Pourvaix's diagram [8], some metal can be dissolved in an alkaline solution and consequently combined with hydroxyl group or oxygen anion forming metalate or metalite. Cobalt also seemed to form cobaltite, HCoOi in strong alkaline solution in the Pourvaix's pH-potential diagram. Based on this information, it was expected that LiCoO2 could be prepared using the cobalt metal in Li OH solution by Soft Solution-Processing. Recently, we reported the successful single step fabrication of electrochemically active LlCoO2 films on the cobalt metal substrate by hydrothermal methods without any post-synthesis annealing as Soft SolutionProcessing [9,10]. Film formation mechanism could be elucidated by the following evidences. . As expected from Pourvaix's diagram, cobalt metal was dissolved in concentrated LiOH solution forming dissolved cobalt species which was detected by an observation of absorption band in UV-VIS absorption spectrum [10]. Thus the reaction was assumed to be started from dissolution. Time dependent potential of Co electrode exhibited only one-step evolution with 0.6 eV from Co metal to LiCoO2 [10]. Another strong evidence was the finding of LiCoO2 powder precipitates at the bottom of tetlon beaker after the reaction [11]. Based on those experimental findings, it was understood that film is formed by dissolution-precipitation mechanism [9-11]."

Jan 1, 2000

By Natasa Mitevska

In order to ensure the minimal copper concentration in the reverb furnace slag, the graphical optimization method is used and the optimal slag composition of the reverberatory furnaces No.1 and No.2 in the RTB BOR, Copper Smelter and Refinery (Serbia) is obtained: (Si02) .. 38.0%; (FeO) .. 40.0%; (Fe3O4) = 5.0%; (CaO) = 5.0%; (Al2O3) .. 6.0%. Keywords: Optimization, Reverb Furnace Slag, Graphical Method

Jan 1, 2003

By Gjergj Dodbiba, Atsushi Shibayama, Toyohisa Fujita, Takashi Shikazumi, Yukio Kato, Kenji Murata

"A new crushing or liberation technique by means of underwater explosion is put forward. This technique is suitable for crushing and liberating various materials, for instance: the electric parts of the discarded portable telephone, CPU from mother-boards of PCs, steel from plastics tubes used as construction materials, waste constructed materials like panels, tungsten carbide scraps, as well as slitting the optical disk (e.g. DVDs), etc. The materials to be crushed are immersed in water and then the explosion is carried out by using only a small amount of explosive. The shock waves in combination with the generated bubbles are very effective in liberating the materials of different densities. It was observed that the metals crushed or liberated by using this technique were leached much faster when compared with the conventional crushing technique. This crushing method can be applied for liberation of many kinds of electric or mechanical tools. Introduction The explosive has been used since Nobel’s invention in 1866. The main practical application of explosion is in the large scale public works, such as dam construction, land development, tunnel, mining and dismantlement of building. The shock wave caused by explosion extremely can generate high pressure able to break the concrete and rock, and other materials. In this study, the crushing and liberation of waste materials was carried out by explosion in water. The idea was to use this technique as a pretreatment stage prior to recycling. The explosion in water can be used to crush hard materials, helping the liberation between different attached materials. The samples used in this experimental work are waste materials such as construction materials, hose, cemented carbide, cellular phone, lithium buttery, DVD-R, etc."

Jan 1, 2008

By Cassandre Nowicki, Louis Gosselin, Carl Duchesne

"Quebec's primary aluminium production industry consumes roughly 39 TWh of electricity per year and is accountable for roughly 7 million tons of CO2 equivalent. By tapping only a small portion of waste heat and integrating it inside the production facility itself, we can significantly reduce GHG emissions and energy consumption. Although the amount of thermal waste can be adequately estimated by applying an energy balance to production processes, this provides very little information on the quality of waste heat and its potential for integration. A measure of exergy is required. Waste heat streams characterized by high exergy content may generally offer valuable incentives for recovery and integration. More generally, exergy values limit integration possibilities. An exergy analysis is provided for the aluminium electrolytic reduction process. This is meant to guide future heat recovery initiatives and energy efficiency measures.IntroductionCanada is one of the world leaders in primary aluminium production and 92% of its aluminium production capacities are located in the province of Quebec. In 2007, production capacity reached 2,786,000 tons in Quebec alone. Since it is estimated that 2.5 equivalent tons ofCO2 are released for each ton of aluminium produced in Canada, Quebec's aluminium production industry is accountable for roughly 7 million tons of CO2 yearly [1, 2]. Furthermore, with an average electricity consumption of 14 MWh per ton, primary aluminium accounts for 39 TWh of electricity per year in Quebec and this energy consumption represents 350 thousand tons ofCO2 equivalent [3, 4]. Natural gas consumption associated with primary aluminium production accounts for less than 1 TWh, but it represents an additional 350 thousand tons of CO2 equivalent [ 4].This work is meant to provide a tool to guide future efforts towards heat recovery and energy efficiency in the primary aluminium industry. Waste heat recovery and thermal integration can cut down both energy consumption costs and GHG emissions. In a primary aluminium production facility, waste heat represents roughly half of the energy input into the Hall-Heroult process. Tapping only a small portion of this energy could reduce natural gas and electricity consumption significantly. In order to evaluate how much of this energy is actually usable, we propose to apply an exergy analysis to individual transformation processes in an aluminium production facility, such that a potential to do work can be assigned to every waste heat flux. The approach will be described in the next section."

Jan 1, 2012

By G. A. Brooks

Reactive ball milling has been proposed as a new route for producing carbides from oxides through carbothermic reduction. It is claimed that through milling oxide and graphite powders to the nanoscale, amorphous materials with very high reactivity are formed, that allows for easy transformation of the starting material to another in a subsequent thermal process. Thermodynamic analysis of this proposed process suggests that unless particle sizes are reduced to below 10nm, then reduction in size alone cannot explain a change in the stability of oxides. Even with nanometer scale powders, the products formed need to have a lower total surface energy than the reactants before a chemical change will occur. A model developed by Bhattacharya and Arzt for predicting localized temperature changes based on milling conditions suggest that temperature rises less than 400 K will be achieved in laboratory conditions. The present calculations suggest that nanometer scale powders formed through high speed ball milling (> I 0 mls) may have undergone a process analogous to melting and quenching. Further work is required to fully distinguish these features.

Jan 1, 2003

By Jie Li, Zhongliang Tian, Xun Hu, Kai Zhang, Yanqing Lai, Hongliang Zhang

The Al-Sc Alloys show many advanced properties for a wide range of engineering applications. But the metal Sc must be added into the metal Al in the form of the Al-Sc master alloy, which is usually produced by the thermal reduction process. In this paper, the decomposition voltages of Sc2O3 and Al2O3 in Na3AlF6-K3AlF6-AlF3 melt were calculated based on the Nernst equation. And the Al-Sc master alloy was prepared in the melt at 950°C by electrolysis. The results show that the Al-Sc master alloy can be prepared by the co-deposition of Sc3+ and Al3+ at the cathode if the concentration ratio of Sc2O3 to Al2O3 in the melt is more than 2:1 under the condition of the aluminum electrolysis. SEM and ICP analysis of the product indicates that the Al-Sc master alloy is made of the phase Al and the phase Al3Sc.

Jan 1, 2016

By Jr. Robison

"Aluminothermic (""thermite"") smelting became commercial with the development of tonnage aluminum, and prospered producing metals and alloys with higher cleanliness, consistency and elemental control than competing technologies. We explore the scope of thermite smelting, and metallothermic smelting in general; the thermochemistry of the process; and its advantages and limitations as applied to industrial production. We review currently-produced products of thermite smelting in several forms and a wide range of heat sizes. As these products serve several industries, we relate the demands of those industries to the requirements imposed on the thermite process, leading to process dynamics and mechanisms to control/alter those dynamics. We review ways to lower the process costs by altering process stoichiometry, using other energy sources and utilizing less costly materials while considering effects on product quality and customer requirements. Finally, we examine overall emissions control and waste disposal.IntroductionAluminothermic smelting is the reduction of various oxides by aluminum to produce metals or alloys with varying levels of residual aluminum. One of the earliest uses of the process was the production of liquid iron to weld railroad rails, later modified in ""thermite grenades"" used to ""spike"" artillery pieces in World War II. Then during the 50's, 60's and 70's the growth of jet aircraft created a demand for new superalloys and titanium alloys, both requiring master alloys for efficient production. Aluminothermic smelting grew with the aerospace industry and with the expansion of microalloyed steels. It is very much a niche industry, dependent on the specialized demands of the specialty steel, superalloy and titanium industries. In this paper we introduce the characteristics of aluminothermic smelting, the scope of smelting operations, the markets served, and the environmental aspects of the process, as seen through the eyes of a company using aluminothermic smelting for over fifty years"

Jan 1, 2012

By Derek Fray

Molten salts have been used for the extraction of metals since the 19th century but, recently, many interesting processes have been investigated using mixtures of molten salts and different cathodic materials. In several existing processes, the cation is simply discharged from melt but, in some cases, complications arise when the electrode potentials of the cations are relatively close. For example, the co-deposition of sodium with aluminium in the Hall-Heroult process is discussed in terms of electrode potentials of the components in the molten electrolyte. Similar considerations will also be given to the anodic reactions with respect to chlorine, oxygen, carbon dioxide or monoxide evolution from chloride-oxide melts. In some cases, the cathodic product interacts with the cathode to produce new and exciting products such as nanotubes from carbon or titanates and reduced titanium oxides from titanium dioxide. Depending on the electrode potentials, it is also possible to completely change the cathodic reaction from discharge of the cation in the salt to ionisation of the anions in the cathode. Examples are given of the reduction of metal oxides to produce metals, high technology alloys and nanomaterials and the cathodic refining of liquid metals.

Jan 1, 2006