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By Mao Chen, Tim Evans, Zhixing Zhao, Weidong Zhang, Baojun Zhao, Dongqing Wang

High temperature softening behaviours of iron blast furnace feeds (sinter, lump and pellet) have been determined under conditions simulated to the blast furnace. The industrial samples were packed with sandwich structure (coke / ore / coke) in graphite crucibles and 30 CO / 70 Ar gas mixture was blowing directly through the bottom of the crucibles. The displacement and temperature were continuously recorded simultaneously to construct the softening curves. Separated quenching experiments were also carried out at selected temperatures under the same gas atmosphere. The temperatures were selected corresponding to the turning points of the softening curves. The phase assemblages and composition of each phase in quenched samples were analysed by Electron Probe X-ray Microanalysis (EPMA). The proportion of the liquid formed at temperature was obtained from the backscattered electron images. The deformation characteristics of these complex multi-phase materials are shown to be related directly to the phase assemblages of the samples and the microstructures. FactSage was also used to assist the predictions of liquid / solid fractions and their compositions.

Jan 1, 2015

By J. H. de. Visser

The transfer of molten metal in smelting or refining operations is typically performed in open trough-type launders that are constructed of either water-cooled copper troughs or refractory lined steel jackets. This transfer can be either continuous or batch. Batch operations transfer metal through an open launder. The uncovered launder has many operational and environmental drawbacks. In order to improve workplace hygiene, designs have evolved toward ventilated launder covers that .are connected to secondary exhaust systems that use negative pressure under the cover removing fume and hot gases to secondary fume control devices. In smelting operations, a variety of covers have been employed which insulate the launder and contain the fumes and also provide additional heat along the length of the launder through a series of premix or inspiration-type burners that add combustion products to the normal fume load in the launder. Cover designs have proven to be inadequate in that hinged unventilated covers hinder convenient access while heated ventilated covers are costly to maintain. Covers that employ refractory bricks and overhead enclosure-type exhaust hoods have been somewhat successful, but restrict operator movement and require large volumes of exhaust air. An example is given of a cover and off-gas system for launders that is designed to provide superior insulation and heating capabilities, as well: as better control of the fume gases-and ease of maintenance. The cover system must maintain the balance between maintaining launder heat and fume removal. The construction of the covers must be able to withstand high internal temperatures and maintain its structural properties.

Jan 1, 1999

By Baokuan Li, Fang Wang, Meilong Shan

"As the advantage of uniform bus loading, the electroslag remelting (ESR) furnaces with three - phase installation by delta or star connection are mainly used to produce the large or super large ingot. The electrical efficiency is significantly improved as the short circuiting through the molten slag. However, little is found about fiindamental research on the electromagnetic field of the ESR system with three -phase installation. A three-dimensional (3D) finite element model was developed to simulate the current density, magnetic field, electromagnetic force and Joule heating for a system of electrode, slag and ingot in the ESR system with three -phase installation.IntroductionThe metallurgical performance of the ingot is the fundament and precondition to obtain the large forging of high quality, which has a critical role in the producing of forging. The electroslag process (ESR) to product the metal materials of high homogenization and clarity become more and more popular[1].The electroslag process is a special smelting technology of producing small ingots, which originate in 1950[2].At present the three, four or six electrode is used in large scale electroslag furnace. It has been found that the deeper molten pool and the wider of the two-phase zone with only one large diameter of electrode to product large ingot effect the solidification microstructure of ingot[3]. However, the molten pool becomes shallow relatively with several electrodes producing the large ingot, which is benefit to the solidification microstructure of ingot. Three electrodes electroslag remelting furnace take the three phase equilibrium power supply to making the load and electric power network balance, avoiding the distortion phenomenon induced by single phase power supply and saving electric power. It also can uniformize the distribution of heat source."

Jan 1, 2012

By Joe Milbourne

The potential for treating copper-nickel-cobalt-platinum group metal concentrates by a fully hydrometallurgical route is discussed. Processes specifically developed for treating these feeds and the potential application of the processes developed for the treatment of chalcopyrite copper concentrates are included in the evaluation. Block flowsheets are provided and the technical characteristics of various processes are compared. The current state of development for each process is summarized and probable economic impacts of the technical features are qualitatively assessed. Perceived risks and rewards associated with each technical concept are provided in the conclusions.

Jan 1, 2003

By Henry Freiser

For the last several years, a systematic investigation of the equilibrium extraction behavior of selective tervalent lanthanides with representative chelating extractions of a variety of chelating agent families has been undertaken for the purpose of learning how to obtain chelating extractants of improved selectivity for separating individual lanthanide ions. The equilibrium extraction data (expressed as log Kex) for each reagent system are linearly related to the reciprocal ionic radius of the tervalent lanthanide ions. The role of adduct formation, steric hindrance, as well as the nature of the bonding atom in the chelate ring, represent some of the factors affecting selectivity arising out of our database of over 200 individual extraction systems, which will be discussed.

Jan 1, 1989

By Kwang-suk You

This paper describes the characteristics of electric arc furnace slag (EAF slag) as an aggregate of concrete along with the chemical composition, leaching concentration of heavy metals, the soundness of EAF slag and compressive strength of mortar with 20% and 50% replacements of sand. The results showed that leaching of heavy metals and soundness of EAF slag satisfied Korean environmental limit and Korean Industrial Standard for aggregates. The compressive strength of mortar increased as the replacement ratio of EAF slag for sand increased.

Jan 1, 2006

By O. Kitamura, H. Kubota

The Harima Works started its ISP operation in 1966 and been expanding its production capacity from 3,000 tonne Zn/month and 1,500 tonne Pb/month to 7,500 tonne Zn/month and 2,500 tonne Pb/month. It is not only treating zinc, lead and bulk concentrates but also secondary materials like Waelz kiln oxide from the Shisaka Works of Sumitomo Metal Mining, waste treatment sludges, industrial wastes and others. Its final products cover Prime Western Grade (PWG) zinc, Special High Grade (SHG) zinc, continuous galvanizing grade zinc, electrolytic lead, cadmium, indium, thallium and sulfuric acid. This paper briefly describes the smelter's historical and present operations. The key data for the current impurity control management and for the distribution of impurities such as copper, iron and arsenic are presented.

Jan 1, 2000

By Ludy C. Motta, Denise C. O. Nascimento, Sergio N. Monteiro

"Natural cellulose-based fibers are nowadays of growing interest for modern industrial composites. Relatively unknown fibers like piassava, curaua and gourde have shown promising behavior as reinforcement of polymeric composites. However, the hydrophilic characteristics of the natural fibers impair its adhesion to the normally hydrophobic polymeric matrix. Surface treatments can, in principle, improve this adhesion and the fiber/matrix interfacial strength. In this paper, the effect of alkali treatment of the surface of piassava (Atallea funifera) waste fibers was investigated in terms of the change in strength of epoxy composites reinforced with these waste fibers.IntroductionThe consequences of global warming and the increase in the price of petroleum are motivating the use of natural materials as substitute for energy intensive synthetic materials [1]. In particular, natural fibers obtained both, from cultivated plants such as jute, sisal, hemp and flax as well as from industrial waste such as sugar come bagasse and coir, are being considered to replace synthetic glass fibers [2,3]. These natural fibers, also known as lignocellulosic fibers, present the comparative advantages of being renewable, recyclable and biodegradable. Moreover, lignocellulosic fibers require less amount of processing energy and are neutral with respect to CO2 emission, which causes the atmospheric greenhouse effect responsible for the global warming [4]. Low cost is another important economical advantage of the natural fibers over the synthetic ones and the application of lignocellulosic is also associated with a lower wear of processing equipment and better finishing of molded components [5]. Moreover, for some fibers, properties such as the mechanical strength and impact resistance can be superiors to the corresponding properties of synthetic glass fiber [6]. The characteristics and properties of several lignocellulosic fibers are, nowadays being extensively discussed in the literature. It is beyond the scope of this work to comment on the hundreds of papers dealing with this subject. However, there are still less known fibers with great potential as engineering material that deserves investigation."

Jan 1, 2008

By Sun Ying, Zhang Jing, Li Qiu-ju, Wang Yan-ze

Copper smelter slag was leached using sulphuric acid solutions under atmospheric conditions. Base on the composition and phase of copper slag, the effect of the concentration of sulfuric acid and leaching temperature to the leaching growth rate of Fe, Cu, Co and Ni in the copper slag were investigated in this paper. Simultaneously, the influence of sulfuric acid concentration, leaching time, leaching temperature and the amount of sulfuric acid (solid-liquid ratio) to the leaching rate of these metal elements were researched. Experimental results showed that: with the increasing temperature, the dissolution rates of the metals elements increased first and then decreased. Due to the influence of silica gel which was obtained in beginning of leaching, the higher the concentration of sulfuric acid is not conducive to dissolution of the valuable metal elements. The dissolution degree of Fe, Cu, Co and Ni were 92.83% 96.76% 93.62% and 63.41% respectively.

Jan 1, 2016

By Neil E. Izatt

The use of Molecular Recognition Technology (MRT), a selective separations technology using specifically designed ligands, has been established as an effective process for removal of metal ions found in many hydrometallurgical, chemical, and wastewater streams. The MRT process has been proven to be highly efficient and effective for indium extraction and recovery from zinc acid leach, electrolyte, chemical process and waste streams. A high percentage of the indium is recovered in a solid product format. MRT has also proven effective for germanium extraction and recovery from similar feed streams. This paper provides the indium and germanium metal recovery flow sheets and analytical results of the metal load and recovery steps.

Jan 1, 2006

By R. Togashi, S. Kuramochi, T. Yamada

In 1972, the Akita Zinc Co., Ltd. commenced operations with an annual capacity of 86,000 tonnes of electrolytic zinc, and it has operated with an annual capacity of 156,000 t-Zn since 1974. The business surroundings for non-ferrous metals production have become more severe with the high Yen rate for the dollar and low domestic demand in the last few years. Consequently, the company tried to survive with some improvements and succeeded to reduce operating costs and to improve profitability as follows: 1) expansion of its production capacity to. 196,000 t-Zn annually, 2) saving man-power by the introduction of fully-automated machines for cathode handling in the cellhouse, 3) improvement of the hematite process by means of the recovery of rare-metals. These improvements made Akita Zinc a competitive refinery in the modern world. We have been trying to improve the operations more and more. One of the challenges is to purify the iron oxide made in the hematite process by applying an As removal process, which is coming into operation in the near future.

Jan 1, 2000

By Karel Verscheure

Hydrometallurgical zinc leach residue, EAF dust and other Zn-bearing by-products pose potentially serious environmental problems that threaten the sustainability of the operations. A pyrometallurgical process designed for treatment of such residues is the high-temperature submerged plasma Zn-fuming process. The successful operation of this process requires high Zn fuming rates whilst retaining vessel integrity through stable freeze-lining. A Zn-fuming model has been developed and used to systematically investigate a range of operating scenarios and to identify potential fluxing parameters such as CaO/SiO2, Fe/SiO2, MgO/feed-ratios in the input and fluxing additions of dolomite for maximum fuming rates and stable freeze-lining.

Jan 1, 2006

By A. N. Lasseigne

Hydrogenation behavior of the NaAlH4 intermetallics is investigated utilizing thermoelectric power and magnetic analyses. Using both thermoelectric power and magnetic susceptibility measurements on these intermetallics allows for confirmation and further insight into hydrogen's role in altering the material's electronic structure. The electronic and magnetic property correlations will indicate the direction for further alloy development to optimize hydrogen storage.

Jan 1, 2006

"Silver is traditionally recovered in base metal smelters (lead and copper), or as a by-product of other precious metals (gold and/or PGM's). This paper presents the results of non-conventional techniques to recover silver from complex materials. The PLATSOL® process has been developed to recover, in one step and without the use of cyanide, base metals (copper, cobalt, nickel) and precious metals (gold, PGM's) from sulphide concentrates too low in grade to enter the mainstream extraction processes. Silver is only partially recovered in solution with gold and the PGM's during the PLATSOL® process. However, the silver minerals are transformed into silver chloride, which can then be recovered from the PLATSOL® residue using conventional techniques. Some South American silver concentrates contain levels of impurity (mostly arsenic) so elevated that the penalties incurred significantly affect the process economics. The present results have shown that a low temperature calcination process transforms the concentrate into a product well suited for traditional recovery treatments. Metallurgical details will be provided, as well as the results of mineralogical studies that helped clarify the process mechanisms.IntroductionSilver occurrences in nature are very diversified, and, therefore, primary silver is produced as a by-product of many base metal and precious metal operations [1], as well as a co-product of most gold ores. However, difficulties can arise when high temperature processes are used for refractory gold ores or copper concentrates, or when the silver concentrate contains impurity elements such as arsenic that trigger high penalties."

Jan 1, 2012

By Xiangjun Zuo, Lifeng Zhang

"Printed Wiring Board (PWB) is a platform upon which microelectronic components such as semiconductor chips and capacitors are mounted. It is also called printed circuit board (PCB). In the PWBs, the organic substances are approximately 72%. The main composition of organic substances in PWBs is ethoxyline resin bromide or ethoxyline resin chlorinate. Depending on the different application and design of the PWB, various metals may be used in the manufacturing process, including precious metals such as copper, lead, silver, gold, platinum, and toxic metals such as mercury, cadmium, barium, gallium, cadmium, lead, bismuth. The current paper reviewed the recycling process for waste PWB materials, including mechanical recycling, combustion for energy recovery and different pyrolysis processes, such as vacuum pyrolysis, atmospheric inert pyrolysi and flux pyrolysis process, and hydrometallurgical recycling process.Backgrounds of Electronic ScrapsProduction and use of electrical and electronic equipment (EEE), such as TV sets, computers, mobile phones and many other daily-life items, have dramatically increased over past decades, while the lifespan of many products becomes shorter"". The rapid innovation in technology in past decades has resulted in availability of cheaper and better electronic products in the market. Thus the production of waste electrical and electronic equipment (WEEE) is also increasing, with estimates of 20-50 million tons per year being generated worldwide2), and it is a problem that governments and policy makers have to handle W). WEEE is also called ""E-wastes"" or ""E-scraps"". From the points of view of recycling and the valuable materials in the used EEE, ""E-scrap"" is more appropriate than ""E-waste"" since the used EEE are not real wastes to be dumped but had much benefit to recycle. In the US, it was estimated that over 315 million computers between 1997 and 2004 and 185 million computers between 2004 and 2007 would become obsolete 5). E-scrap is the fastest-growing part of the U.S. garbage stream 6). It is estimated that only 20% of the E-scrap generated within the US is currently collected and treated, with as much as 80% being unaccounted for7)."

Jan 1, 2011

By Rzyman Michal, Nakamura Takashi, Shibata Etsuro, Grabda Mariusz, Oleszek-Kudlak Sylwia

"Tetrabromobisphenol A (TBBPA) and many systems based on the synergistic effect of brominated organic compounds with Sb2O3 are extensively used as effective brominated flame retardants (BFRs) in many materials such as plastics and textiles. Thermal degradation of BFR containing plastics leads to the formation of hydrocarbons and gaseous compounds such as HBr and SbBr3. Our thermodynamic considerations indicate that these gases can act as bromination agents for metallic oxides such as ZnO, Cu2O, CuO, PbO and FeO. Moreover, these metallic oxides have the thermodynamic tendency to brominate easier than does Sb2O3. The aim of this study was to investigate experimentally the reactivity of ZnO with 1) HBr originating from the thermal decomposition of TBBPA and 2) SbBr3, which is formed during thermal degradation of brominated flame retardant plastics. The thermal treatments of the mixture of compounds of interest were investigated by thermogravimetry coupled with mass spectrometry.IntroductionTetrabromobisphenol A (TBBPA) and many systems based on the synergistic effect of brominated organic compounds with Sb2O3 are extensively used as effective brominated flame retardants (BFRs) in materials such as plastics and textiles. For instance, 4.5 million tons of flame retardant plastics containing BFRs are produced in Japan each year. Thus, in thermal treatments such as the incineration and melting of solid wastes, BFR containing plastics are intentionally or unintentionally included in the wastes. Thermal degradation of BFR-containing plastics leads to the formation of hydrocarbons and gaseous compounds such as HBr and SbBr3 [1-5]. Our thermodynamic considerations [6] indicate that heavy metal oxides such as ZnO, Cu2O, CuO, PbO and FeO should easily react with HBr prior to Sb2O3 and also with SbBr3, the main gaseous product in the thermal decomposition of TBBPA, forming low boiling point metallic bromides suitable for the volatile separation of heavy metals. The metal oxides are also expected to qualitatively and quantitatively affect debromination and decomposition of the flame retardant."

Jan 1, 2008

By Vinay Kumar, Jae-Chun Lee, Abhishek Kumar, Manis Kumar Jha

However, India is rich in ores and mineral, but E-waste recycling is necessary due to the report of national and international studies, which cautioned on the generation, treatment and accumulation of e-waste in India. Current data indicate that the total domestic e-waste generation including imports is around 382979 MT, however waste available for recycling and actually recycled are 144143 MT and 19000 MT, respectively. In which recycling by non-formal and formal sector are 95% and 5%, respectively. On the other hand, India has developed expertise in handling verities of metallic wastes in an organized and safe manner. The development of individual process or combined processes for handling the e-waste is underway. Eco- friendly and energy-saving processes are necessary to comply with stringent environmental regulations. The paper includes the recent trend of e-waste generation, recycling process and its future prospects particularly in India.

Jan 1, 2011

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 José Sancho, Julia Ayala, Purificación García, Begoña Fernández

"A study is carried out to see the adequacy of using flying ashes coming out from a Power Station to eliminate the copper present in waste cyanide waters that are generated in gold mines.Tests were carried out to see how effective the use of ashes taken from two Power Stations could become. Later, the tests are made using ashes coming from Narcea Power Station as this station is near the mine under study.The work is centred on looking for an economically adequate solution to close the waste decanting ponds of the mine. After several tests, a solution is reached through filtration in static layers.IntroductionThe use of coal to adsorb some water-soluble substances has been widely studied [1,2,3,4,] both in the treatment of drinking waters and in determined stages of selective detachment of cyanide gold complexes in cyanide lixiviation processes [5]. Flying ashes sent to the atmosphere by Power Stations as a sub-product of the combustion of this combustible are generally made of more of a 70 % of a vitreous aluminosilicated material and of an active residual material which may be changeable making them potentially useable as adsorbents. Nevertheless, the properties of each kind of ashes depend on the characteristics of the Power Station, of the combustibles being used, of the combustion system, etc.The aim of this work is to demonstrate the adequacy of flying ashes to eliminate the copper present in cyanide waters coming from gold mines either by adsorption or precipitation of the metal. For this study, tests are carried out with Asturian ashes which have a low quantity of lime. The results obtained in the tests demonstrate the effectivity of the method used. To be absolutely concrete, the work is carried out to establish the use of these ashes in the closing of Asturian installations of cyanide lixiviation"

Jan 1, 2008

By Bora Derin, Adnan Aydin, Onuralp Yucel, Hakan Morcali

"The steelmaking industry which uses electric arc furnaces (EAF) generates approximately 250.000 tons of EAF flue dusts annually in Turkey. These flue dusts contain valuable metals such as zinc, iron and lead. For example, if these flue dusts can be treated efficiently, disposal problems certainly decreases and annually almost 40.000-75.000 tons of zinc can be recovered. In this study, powder and pellet forms of EAF flue dusts taken from a steel mill were carbothermally treated in a temperature controlled pilot scale rotary furnace via carbothermal reduction in order to investigate the reduction behavior of Zn and Pb. Temperature (900-1000 and 1100 °C) and time (0-90 minutes) were selected as reaction parameters. The chemical analysis was performed for the sample residues.IntroductionTurkey’s steel production reached to 23.3 million tons in 2006. There are three integrated steel plants of which capacities vary from 0.7 to 3 million tons per year and seventeen EAF steel plants of which capacities vary from 0.06 to 2 million tons per year [1]. When it is considered that more than 74 % of the Turkish steel production is produced by EAF method and approximately 10 - 15 kg of dust is formed per ton of steel during this process, the amount of annual generated EAF dust may be estimated at approximately 0.25 million tons. EAF dust which contains valuable metals such as zinc, lead, iron, cadmium, and chromium, is considered as hazardous waste product in steelmaking industry. If these flue dusts can be treated efficiently, not only the disposal problems certainly decrease, but also annually almost 40.000-75.000 tons of zinc can be recovered. Many studies which exist on recovering of the valuable metals from EAF dust, propose and practice many hydro-metallurgical and pyro-metallurgical treatments [2- 7]. In this study a laboratory scale work were performed to investigate reduction behavior of zinc and lead in EAF dust by carbothermal process in a rotary furnace."

Jan 1, 2008