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By M. Sadayappan

The grain refinement characteristics of four low-lead and lead-free copper base alloys for plumbing applications were investigated. These are leaded yellow brass (C85800). SeBiLOY III (C89550), silicon brasses (C87500 & C87800) and silicon bronzes (C87600 & C87610); Boron and zirconium were found to be the most effective .grain refiners for copper .alloys produced using the permanent mold cast processes. The study indicates that the type of grain refiner to be used is dependent on the alloy type, alloying constituents and their content. After grain refinement, hot tearing resistance of the alloys was improved but mechanical properties remained unaffected. Alloys refined with boron are prone to the formation of hard spots, which will have adverse effect on the surface quality of the castings during polishing and buffing.

Jan 1, 1999

By Ennio Bonetti

The technological applications of MgH2 hydrides for hydrogen storage demand the overcoming of some critical issues: an improvement of the reaction kinetics and a reduction of the desorption temperature. The synthesis of nanocrystalline MgH2 by reactive milling and inert gas condensation and a proper metal catalyst addition, constitute recently employed strategies. In the investigation of the hydrogen short and long-range dynamics, sorption kinetics and nanostructure stability, the mechanical spectroscopy offers some specific advantages. In the present research this technique was employed with other experimental approaches (XRD DSC) to investigate relaxational and structural damping processes in nanocrystalline MgH2 with added catalysts (Fe). Time/temperature variation of the dynamic elasticity moduli and mechanical quality factor are correlated to hydrogen anelastic relaxation processes and concomitant structural transformation of MgH2 to Mg associated to long range H diffusion. Results are discussed with reference to microstructural modification strategies able to assist hydrogen release.

Jan 1, 2006

The presence of clay adversely affects the floatability of copper and molybdenum during processing porphyry copper/molybdenum ores. In addition, reagent consumptions are much higher than when treating clay-free ores. Ores containing kaoline, brammollite, illite and montmorillonite were examined in the laboratory to determine how clay minerals affect the floatability of copper and molybdenum, and to find a possible solution to alleviate the harmful effect of clay slimes. It was demonstrated that the presence of clay mostly affects floatability of coarse and middling particles, and reduces selectivity. The results of the research work showed that there may be several possible ways of reducing the detrimental affects of clay slimes on flotation, some of which include a) use of alternative flowsheets, b) flotation at reduced pulp density, and c) the use of special frothers. The applicability of the findings in plant practice are discussed.

Jan 1, 1999

By W. Persson

The first installation at a copper smelter of a Semtech OPC System for continuous, on-line production control of copper converting in PS converters took place in 1994. At present OPC systems are installed at 19 PS converters. The technology presents to the operator real-time information on the progress of the process he is controlling in the form of optical process parameters, thus facilitating dynamic process control. The optical process parameters are based on time- and wavelength resolved registrations of the light emitted by the off-gas flames and identification of correlation between these parameters and characteristic metallurgical process data. The present paper provides a description of the technology as seen by the furnace operators and a summary of operating experiences made during five years of full-scale, operation at various smelters, reviews influences from the technology on smelter operational practises and comments on recent developments as regards new applications of the technology.

Jan 1, 1999

By R. D. Prengaman

Wrought lead-calcium-tin anodes developed by RSR Corporation have improved the performance compared with the other lead alloy anodes. These anodes have been in continuous service at various locations around the world for as long as fourteen years. Calcium provides mechanical strength to the anode to prevent the deformation while tin increases the mechanical strength, reduces the rate of corrosion, prevents the formation of non-conducting layers on the anode surface, and dramatically improves the conductivity of the anode. Tin is also instrumental in developing the unique rolled structure of the anode which leads to the reduced rates of corrosion, longer life, and improved oxygen evolution. Cobalt additions to the electrolyte further enhance the oxygen evolution and improve the anode life. Higher current densities and higher operating temperatures reduce the anode life. The unique patented method of attaching the rolled anode sheet to the bus bar substantially reduces the resistance of this important joint and offers the substantial savings in power over the life of anode.

Jan 1, 1999

By A. F. Otero

During the electrowinning (EW) of copper significant quantities of highly toxic vapors (acid mist) are produced due to the liberation of oxygen at the cathodes. Acid mist affects the health of operators, the environment and plant infrastructure. Acid mist can be decreased to acceptable levels by a combination of physical means (e.g. ventilation, plastic spheres over electrolyte) and chemical surfactants that decrease the surface tension of the electrolyte, modifying the way oxygen bubbles burst at the surface of the electrolyte. However, only few chemical surfactants are compatible with electrolytic applications, and they are not always used due to their high costs. This paper describes the application of a novel surfactant of natural origin (commercial name Mistop®) to suppress acid mist in copper EW process. Mistop® contains triterpenic saponins derived from the Chilean quillaja tree Quillaja saponaria Molina. The product is non-toxic, and poses no risks to the environment or to EW operators. Mistop® was tested at a laboratory, pilot plant and industrial scale in the world?s largest copper EW production plant at Radomiro Tomic (RT), CODELCO, Chile. At a Mistop® dosage of 8-9 ppm, acid mist decreased below the value accepted by Chilean regulations (< 0.5 mg/m3). At this dosage, Mistop® represents and economical alternative to chemical surfactants, and it is currently industrially used at RT.

Jan 1, 2003

By Jeong-Soo Sohn

Physical treatment and chemical treatment of spent lithium-ion battery were studied in our research team. Especially we developed two types of acidic leaching for crushed powders containing LiCoO2 of spent lithium ion battery. One of them is sulfuric acid leaching with H2O2 as a reducing agent. The leaching rates of cobalt, lithium and the other metals were above 99 % at the condition of 2 M H2SO4, 10 vol. % H2O2, 75 °C, 300 rpm agitation speed, 250 g/5L solid liquid ratio and 75 minutes reaction time. And the other leaching process is the oxalic acid leaching. In this process more than 99% of Li and less than 1% of Co were dissolved at the condition of 3M oxalic acid, 80°C reaction temperature, 300rpm agitation speed, 50g/L initial solid/liquid ratio and 90min extraction time. Each process has its advantage and disadvantage. In sulfuric acid leaching, leaching reagent is very cheap and cobalt could be recovered into cobalt hydroxide. On the other hand, oxalic acid is more expensive than sulfuric acid but lithium could be dissolved selectively. Also cobalt could be recovered into cobalt oxalate and it could be changed into cobalt oxide after heat treatment. In order to select the effective recycling process, recovery rate and purity of cobalt hydroxide and cobalt oxalate were compared and it was investigated which process was more environment-friendly and economical.

Jan 1, 2006

By Howard K. Worner

Several features of smelting and refining operations make them appropriate technology to adapt to the processing of "wastes" not only from the minerals Industry itself, but for wastes in general. These features include significantly higher temperatures than are achieved in conventional Incinerators and also good thermal stability derived from the mass of molten metal and slag in the furnace. This paper expands on Information contributed to the Mervyn Willis Symposium in July 1992 and includes knowledge generated in the last two years of waste processing R&D in a sealed 100kg capacity DC arc furnace specially constructed for the "Environment" process being developed in Wollongong. As one product of-the process is a foundry-type iron, the feed always contained ferruginous dusts or heavily contaminated scrap. For the dusts, sewage sludge has been used as a binder and also as a proportion of the fuel-reductant. To achieve the necessary bath carburisation, It is beneficial to add other lower reactivity carbons such as "kish&apos; graphite, carbon from electrode butts, dusts from coke ovens, carbon from aluminium pot line residues, dry cell batteries etc. Metallurgical factors involved In process control, Including metal and slag, compositions, are discussed.

Jan 1, 1994

By L. B. Tsymbulov

At present data on thermodynamic properties of metallic melts, containing copper and ?iron family? metals, is rather limited. Determination of the activity of metallic melts components under high temperature by experimental methods requires high level of labour inputs. With this it is not always possible to obtain the results with high level of accuracy. Due to that in a number of cases it is more appropriate to apply different methods of analysis, with the help of which there can be calculated thermodynamic properties of ternary and even more complicated systems, prominent thermodynamic properties of binary systems being used as a basis for these calculations. This work presents the results of calculations of different components activity and activity ratio in such ternary system melts as Ni-Cu-Fe, Ni-Cu-Co, Fe-Cu-Co and Fe-Co-Ni. Good compliance of calculations results with those obtained in the course of reliable experimental investigations fulfilment is demonstrated. There are presented the results of activity and activity ration analysis for some compositions of Cu-Ni-Co-Fe system.

Jan 1, 2006

By V. Madhusudhan Rao

Fly ash is a finely divide non ? combustible material obtained as a by ? product of coal combustion. It is a major by ? product of coal based thermal power stations. Until recent past it was considered as a waste and highly polluting material. However its formation can only be minimized by using suitable technology in the boilers. In recent past it is found that Fly ash has many end uses and it has proven itself to be a potential construction material. But the suitability of fly ash for various applications largely depends on the amount of unburned carbon, which is turn depends on the firing method. Fly ash samples from various power plants existing in India using a fluidized bed method and pulverized bed were analyzed and a comparison of these two firing methods was carried. This paper deals with the compositional requirements for fly ash used for the fabrication of insulating doors using AAC (Aerated Autoclave Concrete) and the methods employed to make fly ash suitable for this purpose. It also includes the latest ?U? beam technology for effective fly ash recycle. If the by products of coal combustion from power plants like fly ash as the paper stresses are utilized properly, it is not an exaggeration to say that power generation is possible with absolutely zero cost.

Jan 1, 2006

By Guilian Gao

TbFeCo is a common choice for many rare-earth transition metal films currently used as the magneto-optic layer for magneto-optical: recording devices. Since the environmental stability of RE-TM alloys is typically poor compared with traditional metal oxide particle media, such devices rely on multiple functional overlayers (metallic and/or dielectric) and organic coatings for durability. This paper presents an electrochemical evaluation of the degree of protection of several candidates for the reflective layer, Al, AlCr and AIPt and for the dielectric layer, SiN, AISIN and AIN. Cyclic voltammetry In 0.2M K2SO4 solutions at room temperature revealed that AIPt film offers superior corrosion protection compared to Al and AICr films. Of the three dielectric layers examined, SIN seems to be the most corrosion resistant. Examination by optical and scanning electron microscope confirm the findings of electrochemical experiments. The corrosion resistance of single layers of Al, AICr and AIPt has also been examined and factors affecting their performance are discussed.

Jan 1, 1992

By Rainer Köster, Tobias Wagner, Markus Delay, Fritz Hartmann Frimmel, Wolfgang Ferstl, Wolfgang Höll

"The mobilization of contaminants from industrial residues like ashes from municipal solid waste incinerators in case of leaching is investigated world wide. In classical leach tests only soluble species are considered. In addition the geochemical behaviour of residues has to be completed by assessing the mobilization via colloidal particles. This transport is well known from natural aquatic systems. Quantification of aquatic colloids is associated with considerable difficulties, because they are often found in low concentrations and in a size distribution where small particles with diameters below 0.1 µm predominate. In the past years, the Laser-induced Breakdown Detection (LIBD) has been developed as a novel sensitive method for quantifying colloids. Column leaching experiments with directly coupled LIBD were used to quantify the release of heavy metals and colloids out of bottom ashes. Some typical colloid bound heavy metal concentrations in the leachate are in some cases exceeding the limits defined by German authorities. The LIBD with a flow-through cell allowed to assign absolute values to colloid size and concentration."

Jan 1, 2008

By Jr. Santafé, Lucas L. da Costa, Felipe P. D. Lopes, Sergio N. Monteiro

"Residual vegetable fibers as leftovers from crops, industrial activities and consumable items are realistic options to be incorporated into low cost polymeric composites with the aim of replacing other commonly used materials. The present work assesses the technical properties of epoxy composites reinforced with residual fibers from the coconut fruit, also known as coir fibers. Based on these properties, an evaluation was carried out on these coir fiber/epoxy matrix composites to be used as building panels and furniture in comparison with conventional materials.IntroductionThe utilization of waste from industrial activities is presently recognized as important way in preventing environmental pollution as well as developing new products. This utilization would also generate employment and contribute to environmental improvement in global scale. Among such wastes, those from lignocellulosic materials represent a considerable potential for practical application. In fact, about 2.5 billion tons of these materials are currently available [1], and their fiber content is an important option for composites fabrication. Actually, lignocellulosic fibers are now replacing synthetic fibers as reinforcement in resin matrix composites owing to specific advantages such as low cost, biodegradability and renewable characteristics [2,3]. Moreover, as abundant waste, some of these lingocellulosic fibers could help reducing the use of traditional materials like wood and plastics in many industrials applications. This would prevent further stress on the environment caused by depletion of dwindling resources associated with forests and petroleum."

Jan 1, 2008

By J. L. Bill

The capacity of the Mount Isa Mimes Limited Copper Smelter was expanded in 1998 from 180,000 tomes per year of anode copper to 265,000 tpy. It is based on the innovative Copper ISASMELT technology, which currently treats concentrate at up to 184 tph. Increasing lance-air oxygen enrichment increased the ISASMELT furnace feed rate from 102 to 184 tph. The increased feed rate was achieved without any modifications to the ISASMELT furnace. The first refractory campaign following the upgrade lasted for two years. Future campaign lives of four years or more--without water cooling-are possible. Other Copper ISASMELT furnaces are operating in the U.S.A., Belgium, and India, with additional smelters under construction in China and Germany. In addition, Lead ISASMELT furnaces are operating in the U.K. and Malaysia. The paper discusses the performance of the MIM Copper ISASMELT furnace and the Copper Smelter since the expansion, including operating data and refractory performance.

Jan 1, 2002

By Kwan Soo Han

A thermodynamic model for predicting the distribution coefficients has been developed by taking into account the extraction mech-.ism and the chloride complexation when Sm, Eu, Gd, Tb, Dy and Ho for single component systems are extracted from acidic chloride solutions by di-2-ethylhexyl phosphoric acid and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester in kerosene, respectively. The model equation includes two constants, of which one corresponds to the apparent extraction equilibrium constant and the other is due to the variation of the activity coefficients of organic species. These values are determined from a few experimental data by the curve fitting method Then, the distribution coefficients under untried conditions have been predicted from only the initial data by iterative calculations. Bromley&apos;s formulation is used to estimate the activity coefficients of aqueous species and the interaction parameters for some rare earth chlorides are reported in terms of molality and molarity using data from Spedding et al. The validity of this method has been confirmed by excellent agreement between the experimental and the predicted distribution coefficients.

Jan 1, 1989

Over the years, numerous hydrometallurgical processes have been proposed as an alternative or complement to smelters for the treatment of copper concentrates. Most of these initiatives met with limited success. Bioleaching is applied commercially for secondary copper minerals heaps and dumps, and bacterial leaching processes are being developed for copper concentrates, although industrial application is still years away. More recently developed processes usually include pressure leaching and/or ultrafine grinding. This paper proposes a new leach process to treat copper sulphide ores or concentrates: the process operates under atmospheric pressure and uses limited concentrations of ferric sulphate as oxidant; the key to the process is the regeneration of the ferric ion, which can be effected in-situ (direct process) or ex-situ (indirect process) using SO2/O2. Examples are presented for the treatment of copper concentrates by agitation leach and of copper ores by heap leaching. Application of the process to copper gold ores and chalcopyrite concentrates is also discussed.

Jan 1, 1999

By H. Y. Cheng

A pulse column solvent extraction system was evaluated as an alternative to mixer-settlers for the separation and purification of rare earths. The column tested had an inside diameter of 44.5 mm and had 36 sieve plates with a free area of 25%. Pulsing was provided pneumatically using a solenoid valve controlled by a timer so that both pulse amplitude and frequency could be varied. Feed to the column was a mixed rare earth chloride solution containing 10 g RE L-1. The extractant was 5% Ionquest® 801 in Shellsol 2037 diluent. Hydraulic performance of the pulse column was excellent with no propensity towards stable emulsions or crud formation under normal operating conditions. The column was operated in organic-continuous mode with flow rates chosen so that yttrium and the heavy rare earths were extracted with high efficiency while the light rare earths were rejected. Yttrium extraction varied from 83 to 99.2%. Concentration profiles were measured in both the aqueous and organic phases, and, from this data, the height of a transfer unit (HTU), the mass transfer coefficient (Kxa) and the continuous-phase axial dispersion coefficient (Ey) were computed. The HTU ranged from 17-92 an which is within the range of values reported for other (non rare earth) pulse column systems.

Jan 1, 1992

By G. P. Swayn

Recycling of dusts produced in a flash furnace by direct injection provides the opportunity to reduce recycle loads to the reaction shaft, lower fuel requirements and possibly increase metal recovery to products. Ausmelt has provided an Ausmelt lance system for injecting dusts collected from the waste heat boiler and electrostatic precipitator units, directly into the slag melt. This has been installed and operated in the Kalgoorlie Nickel Smelter with systems for feeding dust, for firing with oil and air, and for raising and lowering the lance. Modelling and testwork development of dust injection, results of commercial trials and design considerations for further opportunities of the Ausmelt lance system, are discussed.

Jan 1, 1994

By Chuan-fu Zhang

In present work, the physical properties of molten FenO-MgO-CaO-SiO2 slags were measured .It is shown by the results that when the slag composition is as follow: MgO 8%~12%, CaO 2%~8%, Fe/SiO2 1.2~1.6, the viscosity of the slags decreases with the increase of temperature. When the Fe/SiO2ratio and the MgO content are fixed, the electrical conductivity increases and the viscosity decreases as CaO content increasing, while the content of CaO exceeds 6% its influence weakens. When the MgO content is 11% and the CaO is 6%, the viscosity of the slag decreases markedly as the increase of Fe/SiO2 ratio. Its influence to viscosity is inconspicuous when the Fe/SiO2 ratio exceeds 1.5. When the CaO content is 6% and Fe/SiO2 is 1.2, the electrical conductivity decreases with the increase of MgO content as temperature is below 1290, but increases when temperature is above 1290. When the MgO content is 11% and the Fe/SiO2 ratio is 1.2, the electrical conductivity increases with the increase of CaO content. When the CaO content is 6% and MgO content is 11%, the electrical conductivity increases as the increase of Fe/SiO2 ratio, while its influence weakens as the temperature increases continuously. The electrical conductivity rises when temperature increases at any slag content. The melting temperatures of FenO-MgO-CaO-SiO2 semi- synthesis slags from this work were below 1290.

Jan 1, 2006

By Neil E. Izatt, Ronald L. Bruening, Steven R. Izatt

"IBC has developed environmentally friendly Molecular Recognition Technology (MRT) processes to selectively extract, recover, and purify a wide range of metals from a variety of process streams. The incorporation of MRT into process flow sheets can improve the economics of the processes. MRT separations are effective even at low (mg/L to \i%JV) metal levels. MRT processes are sustainable, being economically viable, energy efficient, and environmentally friendly as well as having a low carbon footprint. Examples of MRT processes will be presented and discussed involving platinum group metals, gold, rhenium, and other metals of interest to the mining community.IntroductionA significant portion of the earth's precious metal resources has been moved during the past century from underground to above ground [1]. This movement has important economic, health, environmental, ecological, and sustainability implications for the earth and its population. There is concern that recycling of certain precious and specialty metals from end-of-life (EOL) electronic wastes (e-wastes), catalyst wastes, mining waste streams, and other waste products such as rechargeable batteries is not adequate to maintain supplies of these metals sufficient for future needs [2-4]. Improved metal recycling rates and more efficient metal recovery from the enumerated wastes would significantly reduce the amount of virgin metals that must be mined to support our lifestyle [5]. More efficient separation procedures in ore processing flow sheets and more effective recovery of metals from low-grade waste streams would reduce metal loss in the mining industry."

Jan 1, 2012