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By Priscilla Aki Mori de Hanashiro, Viviane Tavares de Moraes, Denise Crocce Romano Espinosa, Hugo Hashimoto

"The LCDs are used in televisions, calculators, mobile phones, computers (laptops and tablets), video games and other electronic devices. The advancements in technology make obsolete these devices, causing excessive disposal of LCDs and therefore decreasing life span of landfills. In this context, the LCDs from LED LCD TVs arise as an additional source of waste electrical and electronic equipment (WEEE). Thus, it is essential to develop LCDs recycling methods, beginning with the LCD characterization followed by displays processing, aiming the materials separation and using some Ore Treatment Techniques, and finally, the recovery of indium using acid leaching. The analysis methods that will be used in this work are: Fourier Transform Infrared (FT-IR) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES).IntroductionLiquid Crystal Display (LCD) technology is applied in modem televisions, calculators, mobile phones, computers and a wide range of electronic devices. It has replaced Cathode Ray Tube (CRT) technology as the most advantageous display product, due to lower electrical power consumption, size and weight reduction, and no radiation emission [ 1]. The constant improving of LCD screen technology reflects on its growing contribution to the amount of waste electrical and electronic equipment (WEEE): an estimated 50 million tons of WEEE are produced every year [2]. Once the most common method of its disposal are landfills, the LCD technology therefore became an environment issue [3].LCD structure is composed by components made by different materials. In order to develop a LCD recycling methodology that gives the right destination to these materials, a previous characterization stage is required. This characterization includes a disassembly process and material identification analysis. One of the LCD components is the screen, which is composed by polymeric and glass layers. The liquid crystal glass was the starting material of this study. It contains indium in the form of indium tin oxide (ITO) film. This ITO film is deposited in the glass by a sputtering process and acts as the electrode material [4,5]. It has in its composition 90% ofln203 and 10% ofSn02 [6]."

Jan 1, 2014

By B. Balamurugan, D. J. Sellmyer, J. E. Shield, G. C. Hadjipanayis, Damien Le Ror, R. Skomski

"Rare-earth transition-metal (R-TM) alloys show superior permanent magnetic properties in the bulk, but the synthesis and application ofR-TM nanoparticles remains a challenge due to the requirement of high-temperature annealing above about 800 °C for alloy formation and subsequent crystalline ordering. Here we report a single-step method to produce highly ordered R-TM nanoparticles such as YCO5 and SmCO5, without high-temperature thermal annealing by employing a cluster-deposition system, and we investigate their structural and magnetic properties. Nanoparticles of size = 10 nm are monodispersed (s /d ~ 0.15) and have Hc values at T = 300 K of 8.0 and 4.5 kOe for YC05 and SmC05, respectively. Alignment of the easy axes is performed via a field applied to the clusters before deposition. These processing steps are highly desirable to create and assemble R-TM nanoparticle composites for future permanentmagnet applications.IntroductionMagnetic nanoparticles with high magnetocrystalline anisotropies (Ki > 1 MJ/m3) are required for permanent-magnet, recording-media, and other significant applications [1-3]. In this regard, bulk rare-earth transition metal alloys (R-TM) especially RC05 (R = Y and Sm) crystallized in the hexagonal CaCu5-type structure have shown a large Ki = 5 MJ/m3 (YC05) and 22 MJ/m3 (SmCo5) along with an appreciable saturation-magnetic polarization (Js, > 10 kG) and high curie temperatures (Tc > 1000 K) [2]. The challenges in controlling the size, sizedistribution, phase purity and crystalline ordering, however, limit the research on RCo5 nanoparticles [4,5]. The conventional arc-melting technique requires high-temperature annealing for alloy formation and subsequent crystalline ordering, which causes excess growth and thus results in nanocrystalline powders of particles sizes larger than 30 nm [6, 7]. Low-temperature wet-chemical techniques yield SmC05 nanoparticles of sizes smaller than 20 nm [5], but the control of phase purity is challenging due to the presence of surfactants and formation of other secondary phases [8]."

Jan 1, 2012

By Kazuteru Tozawa

Surface tension, density and viscosity coefficient of acidic copper sulfate solutions simulating electrolyte solution for electrolytic production of copper have been measured and are summarized as a function of the solution composition and temperature. Nickel sulfatc is taken to be a representative coexisting sulfate that affects the physical properties of the copper sulfate electrolyte solution. The sulfates in the solutions, including sulfuric acid, increase the physical properties under consideration. Gelatin, representing organic additives for electrolyte solution, was found to sensitively affect the surface tension of the solution at low concentration of up to 200mgIL. The surface tension was markedly lowered by the addition of gelatin and the increasing concentration of gelatin led to a more pronounced decrease in the observed values. The surface tension gradually increases with time after addition of gelatin and the increase is enhanced by higher acid concentration and higher temperature. The observed change in the surface tension is considered to reflect the preferential adsorption of gelatin to the bubble-solution interface and the decomposition of gelatin due to hydrolysis to form various molecules having smaller molecular weights.

Jan 1, 2003

By I-Min Lu

An electric field was applied to a metal-bearing kaolinite specimen to investigate the efficiency of electro-osmosis in removing heavy metals from contaminated soils. The electric field induces a flow of water through the porous medium, called electro-osmosis, which is superimposed on the hydraulic flow. Because the electro-osmotic flow is relatively stronger in smaller pores, it can enhance the displacement of contaminated solution by fluid convection. Furthermore local changes in pH caused by the electrode reactions can affect adsorption equilibria and the distribution of solutes between the solution and the solid surfaces. The electro-osmosis experiments were conducted by applying either a constant current or a constant voltage across 8-cm inside diameter, 25 to 30-cm long specimens of kaolinite clay with graphite electrodes. Samples of the pore fluid and of the clay were analyzed to determine metal content, pH, and conductivity as functions of time and position. Results show that removal of heavy metals from soil can be accomplished effectively by electrokinetic treatment of sufficient duration. Approximately 95% of the lead was removed after 189 days.

Jan 1, 1996

By C. M. Diaz

The chemistry of the main unit processes in nickel extractive pyrometallurgy is reviewed. Key re1a ions between smelter feed composition and process selection are discussed, with particular reference to operating conditions, energy requirements and products. The paper a1 so includes a brief discussion of current nickel smelters, based on the results of a recent survey carried out by TMS.

Jan 1, 1988

By Thomas W. Chapman, Shi-Chern Yen, I-Min Lu

"An electric field was applied to a metal-bearing kaolinite specimen to investigate the efficiency of electro-osmosis in removing heavy metals from contaminated soils. The electric field induces a flow of water through the porous medium, called electro-osmosis, which is superimposed on the hydraulic flow. Because the electro-osmotic flow is relatively stronger in smaller pores, it can enhance the displacement of contaminated solution by fluid convection. Furthermore, local changes in pH caused by the electrode reactions can affect adsorption equilibria and the distribution of solutes between the solution and the solid surfaces.The electro-osmosis experiments were conducted by applying either a constant current or a constant voltage across 8-cm inside diameter, 25 to 30-cm long specimens of kaolinite clay with graphite electrodes. Samples of the pore fluid and of the clay were analyzed to determine metal content, pH, and conductivity as functions of time and position. Results show that removal of heavy metals from soil can be accomplished effectively by electrokinetic treatment of sufficient duration. Approximately 95% of the lead was removed after 189 days.IntroductionRemediation of soils contaminated with toxic chemicals is a difficult and expensive task. Washing or leaching are not particularly effective if the contaminate is sequestered in small pores; hydraulic flows of water pass through larger pores leaving the smaller pores relatively untouched. Electro-osmosis appears to be the most promising new technology for removing heavy metals and organic substances from contaminated soils (Segal, 1980; Hamed et al., 1991, Masliyah, 1994).Electro-osmosis is one of several electrokinetic phenomena that occur through the interactions among an electric field, fluid motion, solute adsorption, and the existence of a net charge on a solid-fluid interface (Newman, 1991, Masliyah, 1994). Electro-osmosis refers to the fluid flow in a porous medium that results when an electric field acts on the mobile region of the electrical double layer, the solution-side region of charge separation that exists at the pore walls."

Jan 1, 1996

By William A. Hockings

This report describes the results of laboratory studies on leaching of copper ores.tlf These studies are the first step of a program for the investigation of in situ leaching of tabular, metalliferous ore bodies.(2) The basic steps required in the development of an in situ process are: 1. Leachability - the ability to dissolve the metal values from the ore under in situ conditions must be demonstrated. 2. Ore Preparation - the ore must be prepared so that sufficient contact with the solution can be attained. 3. System Design - integrated in situ systems must be designed and studied for engineering feasibility. 4. Economic Feasibility - the economics of the system must be shown to be economically feasible and competitive. 5. Environmental Feasibility - the loss of reagents into the environment must be investigated. 6. Pilot Scale Testing - the feasibility of the system must be demonstrated on a sufficiently large scale. The studies described in this report were concerned only with the first step of the program, viz., leachability. Native and sulfide copper ores from the Michigan copper district were selected as model ores for these studies. Aqueous amnonia solutions were chosen as the solvents to be investigated. In this study carbonate (CO3, HCO3, H2CO3) was used exclusively as the anion. In keeping with custom it is referred to as carbon dioxide and concentrations are ex- pressed in terms of CO2. When leaching native copper the reaction is

Jan 1, 1976

By V. T. Taniguchi

A process for large scale chromatographic separations using a continuous chromatography technique is described. The process combines the advantages of large scale batch fixed column displacement chromatography with conventional analytical or elution continuous annular chromatography (CAC) to enable large scale displacement chromatography to be performed on a continuous basis (CDC). Such large scale, continuous displacement chromatography separations have not been reported in the literature. The process is demonstrated with the ion exchange separation of a binary lanthanide (Nd/Pr) mixture. The process is, however, applicable to any displacement chromatography separation that can be performed using conventional batch, fixed column chromatography.

Jan 1, 1989

By C. P. Snyman

Three independent methods of coal classification can be distinguished, namely on the basis of grade, type and rank. The latter two can be determined accurately and unambiguously only by means of microscopical techniques. These three independent variables affect all the coal properties and therefore also the technological behaviour of a particular coal. The influence of the inorganic constituents of coal on the fusibility of the ash and on the length of the slag, and also on fouling and slagging, is discussed. The fractionation of the ash-forming constituents during combustion and gasification of pulverised coal shows that fouling and slagging are not related directly to the fusibility and composition of ash of the coal as a whole. The results of combustion experiments using a drop furnace technique indicate that the ignition temperatures of the light volatiles in the coal, and of the formed char, as well as the burn-out time of the char are more dependent on the rank than on the type or grade of the original coal. High-ash coals, however, apparently ignite at lower temperatures and are more reactive than low-ash coals of similar type and rank. The surface properties of coal, which are important in froth flotation and oil agglomeration, correlate well with the inherent moisture content (and by inference with the heat of wetting and the calorific value) and therefore with the type and rank of the coal. In coal exploration, variations of rank offer the possibility of predicting the presence of an intrusion near the seam, thus contributing to more effective exploration and mine planning.

Jan 1, 1991

By Lionel Ryan

In 1996, the Dominican Republic operation of Falconbridge (Falcondo) developed a 5-year Process Control Plan in conjunction with the corporate Process Control group located in Sudbury, Ontario, Canada. This plan was further refined into an analysis of the areas of the highest potential economic return for the company with the reduction shaft furnace operation being the most promising. Historically, the reduction plant, which comprises 12 shaft furnaces, has been the bottleneck of ferronickel production. Since 1996 there has been a history of control development, and the current status is that all 12 furnaces are using advanced model-based multi- variable predictive control. The combination of advanced process control (APC), improved control system performance and improved process information management has resulted in an increased throughput of 6% per shaft furnace and a reduction in operating costs of 4.5 US cent/lb of Ni. This paper reviews some of the major milestones that have been achieved in this development Keywords: Advanced Process Control; Model Based Predictive Control; Connoisseur, Reduction Shatt Furnace; Nickel Laterite Ore; Ferronickel; MonitorMV

Jan 1, 2004

By R. S. Tahautdinov, A. N. Posazhennikov, V. V. Bastrygin

"The Bakal (South Ural, Russia) deposit of iron ore bearing iron carbonate (siderite) with the capacity of more than 1 billion tones belongs to the MMK. This ore cannot be fully processed via blast furnace technology because of high content of MgO. According to the investigations carried out in the USA and Japan in 1999-2004 the ITmk3 (Ironmaking Technology mark three) RHF technology is a breakthrough in Ironmaking. Four iron ore types (hematite, magnetite, high and low Al2O3/SiO2) were tested. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from iron carbonate bearing ore via the ITmk3 by means of the lab scale testing. Samples of iron ore and carbon reductant were chemically and physically analyzed. Green pellets were processed via a lab tube furnace to simulate RHF conditions. The nuggets and slag were chemically analyzed. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities in 1996 [1]. After pilot testing at Kobe Steel’s Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics has committed to building the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota). Only 4 iron ore types (hematite, magnetite, high Al2O3/SiO2 and low Al2O3/SiO2), as well as 4 coal types with range of volatility, ash and fixed carbon were tested. Results were consistent with nugget characteristics confirming ITmk3’s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from iron carbonate bearing ore with high content of MgO has been done. Such kind of iron ore is restricted for charging into the blast furnace due to contamination of MgO. The reason for restriction is the limitation of load of MgO in the blast furnace. If a lot of MgO enters the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace."

Jan 1, 2011

By Katsunori Yamaguchi

Secondary materials, that contain relatively high concentrations of platinum group metals, (PGMs) are treated in copper smelting process. The PGMs lost in the slag is increasing with increasing quantities of scrap treated amount. To determine the portion of the PGMs chemically dissolved and that associated with the mechanically trapped matte in the slag will be a key factor to improve the recovery of those metals. An experimental study was carried out to determine the distribution of palladium between the FeOx–SiO2 slag and the liquid Cu2S–FeS matte at 1573 K and a fixed partial pressure of SO2 of 0.1 atm. It was found that the distribution ratios are around 10−3 for platinum and palladium. The distribution ratios show a tendency to increase when the grade of matte is increased above 60 mass% Cu. In addition, the solubility of platinum in FeOx–SiO2 slag equilibrated with a pure palladium and the Pd-Cu alloy was determined at 1573 K and the range of oxygen partial pressure from 10−9 to 10−7 atm. The solubility of palladium in the slag tends to increase with increasing oxygen partial pressure and activity of CuO0.5 in the slag.

By Lloyd R. Nelson

Selective carbothermic reduction is the preferred method of treatment of electric arc furnace (EAF) dust (listed hazardous waste, K061). The process maximizes the recovery of recyclable constituents by concurrent production of saleable zinc metal (directly condensed from the furnace off-gases), an innocuous, disposable iron oxide-rich slag, and some metallic iron. Results of a mineralogical investigation of a foaming slag produced during selective carbothermic reduction treatment of EAF dusts are presented. Wiistite and tricalcium silicate were identified by reflected light microscopy as the primary crystalline phases contained in a glassy matrix, but this technique failed to reveal any solid phases that could have significantly contributed to foam stability. It was concluded therefore, that the foam had been unstable, and had been primarily generated by copious gas evolution associated with the sudden reduction of the slag by an inadvertent addition of carbonaceous reductant. This is consistent with the susceptibility to foaming, when subjected to sudden excesses of carbon, of the slags produced by selective carbothermic reduction, because they still contain unreduced components such as iron oxide.

Jan 1, 1994

By R. Craig McClung

Contrary to other sulfide minerals, where recovery is principally liberation controlled, the recovery of molybdenite is more complex. It is this complexity that initiated a geometallurgical investigation of molybdenites from Bingham Canyon. The aim of this investigation was to determine the effect mineralogy and/or mineralogical attributes have on recovery. All samples were analyzed using normal mineralogical techniques. The results reveal the presence of two distinctly different types of molybdenite. These have been identified as the two polytypes of molybdenite: i.e. hexagonal (2H); and rhombohedral (3R). The 2H-polytype occurs as textbook-shaped particles in quartz-molybdenite veins that are located in the current pit bottom. The 3R-polytype occurs as disseminated, “ball”-shaped particles with a dull or frosted appearance and are concentrated along the margins of the current pit. Concerning their metallurgical behavior, each type exhibits unique metallurgical properties that are consistent with those reported in the published literature. The 2H-polytype is easily ground and kinetically “faster” floating with surface attributes that are amenable to higher rates of recovery. This results in the production of a high quality concentrate under normal operating conditions. The 3R-polytype, by comparison, is difficult to grind and kinetically “slower” floating with surface attributes that are less amenable to recovery. Therefore, in deposits with higher concentrations of the 3R-polytype, modifications to the normal operating parameters may be necessary to improve recovery. This investigation highlights the necessity for understanding the mineralogical characteristics of any economic mineral(s), as these will have a direct impact on recovery.

By Zhongning Shi, Ramana G. Reddy

"By cyclic voltammetry and potentiostat electrodeposition using Potentiostat/Galvanstat, electrochemical behavior on Ag electrode in electrolyte 0.2M NaOH+0.01MPb(NO3)2-0.01M TeO2 -0.01M TlNO3 solution were also carried out at 298K. The processes of electrodeposition of Tl2Te3 and PbTl4Te3, a thermoelectric material, are reported along with analysis of the composition of the obtained deposits. The results showed that two different underlying processes are occurring depending on deposition potential. One process involves the reduction of TeO3 2- and Tl+ to Tl2Te3 in a potential interval of -0.70V < E < - 0.89V (vs. Hg/HgO). A second process at more negative reduction potentials involves reduction of TeO3 2-, Pb2+ and Tl+ to PbTl4Te3 in a potential interval of -1.02V < E < - 1.19V. The crystalline Tl2Te3 and PbTl2Te3 were deposited electrochemically on Ag substrates at -0.84V and -1.10V respectively. Thermoelectric (TE) material can form a temperature gradient across the material to make electric voltage, which is popular in waste heat utilization and recovery industry. Lead telluride, PbTe, is a small band gap semiconductor of 0.32eV at 300K. PbTe can change its n-type semiconductors with Pb-rich to p-type semiconductors with Te-rich[1]. And it is one of the best TE materials used in thermoelectric generators working between 500K and 600K, or even at a higher temperature of 800K.Three facto,rs play a role in the performance of a thermoelectric material: electrical conductivity (s), thermal conductivity(?), and the Seebeck coefficient (S). These can be combined with absolute temperature (T) to give a figure of merit (ZT) for the material, ZT = s2sT/?. By increasing the electrical conductivity and decreasing the thermal conductivity, which can enhance the ZT value, many efforts, such as alloying with other elements and making the materials nano-sized, have been done to improve its properties recently. Hsu et al. reported that the ZT value of Cubic AgPbmSbTe2+m is increased to 2.2 by doping Ag-Sb to PbTe.[2]."

Jan 1, 2011

By Ko-ichiro Ohno

It is recently recognized that the iron reduction and melting as well as the slag separation of a composite of granular iron ore and coal are completed in a very short period of about 10 minutes when the composite is rapidly heated up to approximately 1673K. These phenomena are expected to be applied to a new iron-making process. The mechanism of iron ore reduction and iron-slag separation during rapid heating has not yet been revealed and the fundamental research has just started. Carburization of the reduced iron is regarded as one of the most important steps in this process. In the present work, the composite was prepared from four kinds of coal or graphite as a carbon source and electrolytic iron powder as a completely reduced iron ore. The temperature at which the liquid formation and iron carburization occurred was monitored. Direct observation of smelting reduction behavior was made by a confocal laser-scanning microscope combined with the infrared image-heating furnace to clarify the effect of molten ash on iron carburization. It was found that the meltdown temperature of composite became lower as the melting temperature of coal ash decreased. From the observed result, it was presumed that the liquid slag would act as an important media for the carbon transfer from coal to iron. The carburization mechanism during the smelting reduction was estimated as follows. When slag containing iron oxide melted down and contacted carbon, iron oxide in the slag was reduced and the formation of the metallic iron particle as well as the its carburization occurred simultaneously at the slag-carbon interface. Carburized iron particle was carried from slag-carbon to slag-iron interfaces due to the slag convection flow caused by the difference of the interfacial tension between the carbon-slag and iron-slag interfaces. Carburization of reduced iron could proceed with a repeat of the above-mentioned process.

Jan 1, 2003

By Congcong Yang, Jian Pan, Deqing Zhu, Yang Zhong

A study of pelletization of one imported chromite concentrate with coarse site, poor ballability and refractory roasting performance was conducted in small scale tests, and high pressure grinding rollers (HPGR) was used to improve the pelletization. The mechanism of HPGR was revealed by means of SEM images and optical microscopy. Compared with the ball milling pretreatment, HPGR pretreatment can not only enhance the ballability of pellet feed but also drop the roasting temperature. Fired pellets, containing proper chemical compositions with high compressive strength of 2917N/pellet and good metallurgical performances, have been manufactured. The mechanism of HPGR reveals that chromite particle surface turns to more irregular after HPGR treatment and more new surface being formed because of more cracks, sharp corners and edges appearing, resulting in higher surface chemical activity, all of which improve the ballability of the chromite concentrate and contribute to the consolidation of fired pellets.

Jan 1, 2015

By Takahiko Okura

Japanese non-ferrous industry introduced large-scale smelting plants along seashores for overseas concentrates with increasing demand of metals around 1970s. Although serious environmental pollution became obvious, with economic growth, the industry got rid of pollution by installing new processes and improving operation technologies. At present, over 99.8% of sulfur input to smelters is fixed as stable compounds. Through those decades Japan had steep rises of oil prices, sudden change of exchange rate, and inadequate treating charges, we were faced to consider the closure of smelters. The industry has survived by increasing productivity, saving energy and reducing manpower. Furthermore the industry made great effort to recycle valued metals from scraps and wastes for the resources-recycling society. Academic research also contributes to support these individual technologies. Thus the industry has fostered world-acclaimed technologies in terms of efficiency and energy conservation. This paper presents technology development and environmentally-benign sulfide smelting processes.

By A. M. Strachan

Capper Pass & Son Limited Was, until its recent closure, the world&apos;s largest producer of tin from secondary materials including solder drosses, non-ferrous smelter flue dusts, tin based metal alloys, residues and slags. Polonium-210, an alpha emitting radionuclide, was present in varying concentrations in some of the numerous feed materials processed by the smelter and refiner. The polonium-210 followed a complex path through the process flowsheet. This paper discusses the behaviour of polonium, both from its arisings in other smelters&apos; process streams and through the entire Capper Pass smelting and refining circuit. The consequential personnel safety and environmental precautions necessarily taken in some areas of the process operation are outlined.

Jan 1, 1992

By K. D. Mondale

The chemical and physical properties of samples from ten sedimentary zeolite deposits. (representing chabazite, clinoptilolite, erionite and mordenite types), have been determined as a prelude to the development of a wet beneficiation process. The mineralogical composition of each deposit and such properties as morphology, size, apparent density, surface area, pore volume, relative hardness and zeta potential in solution have been determined. Some of these properties, especially apparent density and relative hardness, were found to differ significantly from textbook values. Based on differences in properties between the zeolites and their associated gangue minerals, a wet beneficiation process has been developed which makes use of selective grinding, sizing, sorting and gravity concentration. Additionally, an alternative upgrading process using flotation has been developed for one of the deposits.

Jan 1, 1988