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Hazardous waste has often very complicated chemical compositions in a variety of physical forms and is normally processed in rotary kiln incinerators. Due to large variations in waste types and difficulties in feed characterization, the complex transport processes within the incinerator are not well understood, and the incineration process meets challenges in a smooth operation, and expects various uncertainties in the process chemistry and emission control. For better understanding of the incineration process, simulation was carried out by using Computational Fluid-dynamics (CFD) to characterize temperature and species distribution in the incinerator. In order to catch certain aspects of thermal and chemical behavior, a novel approach is proposed to represent approximately the waste streams and the subsequent combustion process. Hazardous waste in various forms from an industrial-rotary-kiln waste incinerator is firstly converted to a hydrocarbon-based virtual fuel mixture with approximately the same HIC molar ratio and calorific value. The simulation of the combustion process of the simplified hazardous waste was proceeded with a combustion model. The distribution of temperature and chemical species especially the remaining CO in the system is preliminarily investigated. Distribution of CO concentration, as a good indicator of emission level for the incineration process, could be used to evaluate the emission control. The predicted temperature distribution has been compared with available measurement data from an operating rotary kiln waste incinerator at AVR-Chieme, in the Netherlands. Reasonable agreement has been reached between the measured and predicted temperature data. In the next step, measurement of species distribution in the system is planned to further validate the combustion model.

Jan 1, 2003

By William A. Apel

Several different strains of bacteria have been shown capable of reducing hexavalent chromium, Cr(VI), to Cr(III), a less toxic, .. more readily recoverable form of Cr. This paper examined the Cr(VI) reduction efficacies of 3 different Cr(VI) reducing bacteria: Pseudomonas f1uorescens LB300., Pseudomonas aeruginosa PAOI, and Pseudomonas aeruginosa PAOI (pCROI) It was demonstrated that all three bacterial stratns reduced Cr(VI) primarily during their exponential growth phases while using glucose as their carbon and energy source. Significant differences in the three organisms' Cr(Vl) reduction capabilities depending on initial Cr(VI) concentrations were also demonstrated. P. aeruginosa PAOI showed superior Cr(VI) reducing capabilities over the. entire range of Cr(VI) concentrations tested while the Cr(VI) reduction capabilities of the other two strains were increasingly inhibited as Cr(VI) concentrations increased.

Jan 1, 1991

By U. Meyer, A. Alonso, P. Banios

The sampling of cathodes has changed with the introduction of the ISA-process in copper refineries. A Jernkontoret joint working group of refineries and rod plants from both primary and recycled copper plants has been investigating whether the actual sampling of cathodes is representative for this type of cathodes. As a first stage, samples were sent to the members of the working group with the objective to find an easy basis for a comparison of the results of the next stages. All samples show the same tendency for nearly all elements. In some cases, there may exist differences in calibration and for some elements the detection limits are too high, especially when Optical Spectrometry is used. In the second stage, discs were compared with melted samples to answer the question whether the punching of discs is sufficient for the quality control of the cathode. The analyses of the discs represent fairly well the cathode quality. There are differences between cathodes from different crops. Three punches are sufficient to determine the cathode quality. Finally, samples from various lots of cathodes were compared with samples from the rod produced from these cathodes. The impurity content of the rod corresponds to the impurity content of the cathode.

Jan 1, 2000

By Viviane Tavares de Moraes, Denise Crocce Romano Espinosa, Jorge Alberto Soares Tenorio, Adriana Johanny Murcia Santanilla

"Increasing volumes of solid waste are generated worldwide, due to the continuous technological advances, the electronic scrap is part of these waste, requiring the study of recycling processes to stimulate this activity or the reuse of its components. The separation of nickel from sulphate leach solution, which also containing iron, zinc and aluminium was carried out using bis-(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) as extractant, in order to determinate the effects of pH and temperature. The number of stages required for extraction was also assessed. The results showed that the metal extraction increased with increasing pH. On the other hand, increasing temperature was not favorable for all metals. However, under conditions used in this paper the purification of solution containing nickel was possible.IntroductionIncrease in the demand of metals in the world for use in industry causes a great exploration of natural resources. One outcome of this is increased investigations for the recovery of metals from industrial wastes. Nickel is found in wastes, such as batteries and electric and electronic devices, this kind of waste becomes a significant source for metals recovery. Since nickel is also present in printed circuit boards, which are associated with electric and electronic equipment, it can be recovered from this kind of waste through different techniques. It is important to highlight that iron is generally associated with this scrap [1] and for its removal chemical precipitation is often used. On the other hand, the solvent extraction process is widely used for treatment of leach liquors, because it can be produce high purity solutions [2, 3]. This technique is based on the purification of solution using contact between a liquor leaching and the immiscible organic solution, which contains an extractant that promotes the desired metal transfer [4]."

Jan 1, 2012

By Richard H. De Voto

The McDonald Gold Project and two satellite gold deposits near Lincoln, Montana, contain at least 9.9 million ounces of gold and 30 million ounces of silver. The McDonald gold deposit alone contains 7.2 million ounces of gold reserves that can be open-pit mined and processed by cyanide heap leaching at a projected cash operating cost of $190 per ounce. The deposit is predominantly oxidized with no chance of acid production, and can be mined, operated, and reclaimed with minimal permanent environmental disturbance other than the creation of an open pit filled with a fresh-water lake which would support trout. The Seven-Up Pete Joint Venture, the owner of the McDonald Gold Project, commenced permitting of an open-pit, heap-leach operation in November 1994. In 1998, Montana citizens passed an anti-cyanide, open-pit mining initiative, 1-137, which banned any new open-pit gold mine which uses cyanide processing, The Venture has conducted extensive studies, including metallurgical testing of the treatability of McDonald ores with alternative lixiviants, and has determined that all other mining and metallurgical treatment systems are vastly uneconomical in the recovery of gold and silver from the McDonald deposit. Therefore, the Venture's proposed open-pit mining and cyanide heap-leach processing is the only technology that can be applied economically to the McDonald deposit. Further, the analyses convincingly demonstrate that the proposed open-pit, cyanide heap leaching technology results in maximum resource conservation of this valuable and unique deposit and poses far less risk to human health and the environment than any of the alternative technologies.

Jan 1, 1998

By Mark Jolly, Nasim Soleimanian

"During the last 20 years CFD (Computational Fluid Dynamics) has been used as a tool to aid furnace designers and manufacturers to improve energy efficiency and effectiveness of glass furnaces. However as the models are maturing the effect of feeding equipment used to push the raw material into the furnace has not been included in the process models. This paper investigates the effects of batch pattern in the melt space caused by charging equipment on the energy efficiency of the furnace focusing on the melting zone. A simple batch patterns sensitivity study has been performed using purpose built software (Glass Furnace Model-GFM). It is concluded that in order to further reduce the energy consumption of the furnace it is necessary to model the batch charging process in more detail to find more opportunities for improvement.Introduction Glass manufacturing is a conservative industry which applies to all the four major segments (float glass, container glass, fiberglass, and specialty glasses). Risks due to the high capital investment, very long service life of the furnaces, and the demand for high performance and quality from the outset translates into evolutionary progress rather than revolutionary. The main problem facing glass manufacturers are the financial cost of manufacture, its impact on the environment, and mounting pressure imposed by the authorities for greener manufacturing and reduction in emissions.The main energy intensive activities involved in continuous glass manufacturing are: the need for high temperature to create and maintain the viscous flow, homogenisation of glass melt (melt residence time), and maintaining the two to achieve continuous output of glass at the right quality. The high temperature and long duration of homogenisation has resulted in the design oflarge furnaces, which have high energy consumption, low specific performance, and high C02 emissions. As an example in the container glass sector the most efficient furnace has a specific primary energy consumption of 3.8 GJ /tonne of glass at a level of 50% cullet in the batch. Even very small improvements in efficiency by optimising operation would have a high impact [1-14]. Given the conservative nature of the industry and the costs involved in experimental data gathering, CFD modeling of the process has been used extensively during last two decades to not only improve our understanding of the process but also as a tool in predicting possible optimisation windows, e.g. Glass Furnace Model ( GFM), a commercially available piece of software that has been developed to optimise furnace operation."

Jan 1, 2013

By Alice Barreto Bevitori, Frederico Muylaert Margem, Noan Tonini SImonassi, Caroline Oliveyra, Sergio Neves Monteiro, Isabela Leão Amaral da Silva

"The mechanical behavior and the fracture characteristics of composites with DGEB/TETA epoxy matrix reinforced with up to 30% in volume of continuous and aligned ramie fibers were evaluated by tensile tests. Specimens with selected thin fibers aligned along the tensile axis were room temperature tested to rupture. The fracture surface was analyzed by scanning electron microscopy. The results showed significant increase in both the ultimate tensile strength and the elastic modulus. The fracture analysis indicated the possible mechanism for the fiber/matrix interaction, which could be responsible for the composite performance.IntroductionSince the middle of last century, polymer composites have substitute many conventional monolithic materials in applications ranging from aerospace to sport [l]. The main advantages of these composites are the low density and flexible properties specially using fiber as reinforcement to suit the mechanical performance requirements [2]. These are usually high strength and stiffuess requirements that could be reached with synthetic fibers such as gloss, carbon and aramid fibers. Its most commonly used example is ""fiberglass"", i.e., a thermoset polymer matrix composite reinforced with glass fiber. Indeed, ""fiberglass"" has a specific strength of the order of 500 MPa.cm3/g, which is the double of the strongest steels like the maraging. This motivated, at earlier times, ""fiberglass"" to replace many conventional materials including wood and natural fiber composites. Today, ""fiberglass"" has a wide range of uses from aerospace systems and appliances to sport and leisure components. However, its fabrication as well as those of any synthetic fiber such as carbon and aramid composites, requires a relatively large amount of energy. Presently, a growing concern exists regarding the consequences to the environmental by gases like C02 associated with both the energy consumption and the processing of synthetic fibers and their composites. These gases are well known responsible for global warming [3]."

Jan 1, 2013

By Jennifer Mager, G. P. Martins, Dean Mussatti

"The role of lead, at low concentrations in high pH cyanide-electrolytes, on the dissolution behavior of gold, has been a topic of scientific and industrial concern for well over a century. The recent paper by Kondos et al [1] at CANMET (1995) this continuing interest and apparent importance. Nevertheless, the mechanism(s) by which this (and other heavy metal) component influences the electrodics of this electrochemical system has still not been unequivocally demonstrated. Instead, several plausible hypotheses, by pioneering researchers in this field, have been advanced and reiterated OVer the ensuing years. While it is generally accepted, based on equilibrium elctrode-potential calculations, that reduction (or co-reduction when oxygen is present in the electrolyte) of lead on the gold surface may occur due to cementation (contact reduction), the cemented lead has never been characterized. The work presented has reexamined the role of lead in this system, by delineating the species distribution of these system components and by interpreting the results of potentiodynamic studies in conjunction with SEM analyses of a gold electrode.1. INTRODUCTIONThe leaching of gold ores in cyanide electrolytes has been practiced for well over a 100 years. Research conducted on this topic has been primarily focused on the effects of operating parameters such as concentrations of oxygen and cyanide, and the pH of the electrolyte; or the leaching behavior of carbonaceous and sulfitic gold-bearing materials.Mechanisms by which pure gold is leached in alkaline cyanide media, with oxygen serving as the oxidant, have been subjected to continual examination and re-examination in the published technical literature during this century. Recently, it has been speculated that without the presence in the electrolyte of trace heavy metals, such as lead or mercury, that gold would not be leachable. Researchers who have tackled this topic, have either considered heavy metals to be a natural occurrence in these systems and ignored the role they may serve in the leaching process, or they have deliberately focussed on controlling their concentrations in the system to undetectable limits. As a result, conflicting findings have been reported for what would appear - depending on the details provided in these reports - to be identical systems."

Jan 1, 1997

By Mariana Barcelos, Frederico Muylaert Margem, Giulio Rodrigues Altoé, Pedro Amoy Netto, André Gomes, Sergio Neves Monteiro

Environmentally correct composites, made from natural fibers, are among the most investigated and applied today. In this paper, we investigate the mechanical behavior of polyester matrix composites reinforced with continuous fique fibers, through bending tensile tests. Specimens containing 0, 10, 20 and 30% in volume of fique fiber were aligned along the entire length of a mold to create plates of these composites, those plates were cut following the ASTM standard to obtained bending tests specimens. The test was conducted in a Instron Machine and the fractured specimens were analyzed by SEM, the results showed the increase in the materials tensile properties with the increase of fiber amount.

Jan 1, 2015

By Shantaliu S. Shevade, Muhammad M. Rahman

"This paper presents a systematic analysis of fluid flow and heat transfer processes during the magnetic heating of the substrate material. Heat is generated in the substrate material when a magnetic field is imposed due to change in orientation of the molecules. As a result, the substrate temperature rises. The i;tudy considered microchannels with rectangular and square cross section with heat generation in the substrate due to imposed magnetic field. The results computed were for Gadolinium substrate and water as the working fluid. The purpose of this study is to explore the transient heat transfer coefficient when the fluid is circulated through the substrate via microchannels. Equations governing the conservation of mass, momentum, and energy were solved in the fluid region. In the solid region, heat conduction was solved. From the simulation results, plots of Nusselt number and heat transfer coefficient were obtained over the length of the channel. A thorough investigation for velocity and temperature distributions was performed by varying channel aspect ratio, Reynolds number, and heat generation rate in the channel. It was found that the peripheral average heat transfer coefficient and Nusselt number is larger near the entrance and decreases downstream because of the development of the thermal boundary layer. With the increase in Reynolds number, the outlet temperature decreased and the average heat transfer coefficient increased.IntroductionMagnetocaloric effect (MCE) is the heating or cooling of the magnetic materials due to varying magnetic field. The effect was originally discovered by Warburg. Magnetocaloric materials store heat energy in the way the atoms vibrate and in the way electrons spin within each atom. More heat energy increases the vibrations and also makes the spins more random. When a strong magnetic field is applied to a magnetic material, the magnetic moments of its atoms become aligned making the system more ordered. The more ordered material has lower entropy and compensates for the loss by heating up. When the magnetic field is removed, the magnetic moments return to their random directions, entropy increases and the material cools. Gadolinium is a magnetic material that exhibits high temperature rise during adiabatic magnetization around its transition temperature of 295 K. It has been experimentally observed that adiabatic temperature rise increases with magnetic field strength and can be as high 20 K when a magnetic field of IO T is applied. Thus magnetic field, when applied to a microchannel heat exchanger, causes temperature change in the magnetic material. The fluid flowing through the channel gets cooled or heated due to this adiabatic temperature change."

Jan 1, 2004

By S. Malinov, J. J. McKeown, W. Sha, S. McShane

"A model is developed for prediction of fatigue stress life S-N diagrams for Ti-6Al-4V alloy at different conditions, using Artificial Neural Network (ANN). Different factors which have influence on the S-N diagram are involved as input parameters of the NN, namely microstructure, environment, texture, test/work temperature, surface treatment and stress amplitude. As the output the S-N fatigue diagram is simulated and plotted.The model is based on standard multilayer feedforward neural network. The NN is trained with a comprehensive data set collected from the literature, using Levenberg-Marquardt training algorithm in combination with Bayesian regularisation. A very good performance of the trained Neural Network is achieved. Good correspondence between ANN"" prediction and experimental S-N diagrams is observed. Using the model S-N diagrams for different conditions are predicted and analysed. Graphical User Interface is developed for use of the model. We believe that the model will be important for practical applications in solving various problems on fatigue behaviour of the titanium alloy.IntroductionTitanium and its alloys have an increasing range of applications due to their very good combination of mechanical properties, corrosion and erosion resistance. They are currently finding widespread applications in many industries due to their desirable and versatile properties. Most important among the alloys is Ti-6AI-4Y. Jet aircraft manufacturers are the principal 'consumers of Ti-6Al-4V and it is often specified for critical parts, the failure of which could result in the loss of an entire system. A generic class of Ti-6AI-4V has been developed over the past years and it has become the best understood of all the titanium alloys. The advantages of titanium alloys include: (i) low densities, giving very attractive strength to weight ratios allowing lighter and stronger structures; (ii) superior corrosion and erosion resistance in many environments; (iii) high temperature capability. Although the titanium materials are still considered as expensive materials, for many applications the cost of titanium alloys can be justified on the basis of their desirable properties."

Jan 1, 2001

By Santo Ranieri

We will briefly review the nickel market in 2003 and look forward to the supply demand balance for the next few years focusing in on the key factors influencing future price dynamics. On the supply side we will examine slated brownfield and greenfield expansions including the Norilsk factor and the small to mid-range 'supply creep'. We will also review the cost side of the industry and what to expect going forward. On the demand side, we will discuss the stainless steel and non-stainless demand, the China factor and the stainless steel scrap supply cycle. We will conclude by pinpinting where the market is on the current price cycle, and where we believe the mid-term direction is headed.

Jan 1, 2004

By Robert S. Gärtner

The selective aluminum extraction by 3 different calixarenes (p-tert-butyl-calix[4]arene-tetra¬2-acetic-acid-ethyl-ester, p-tert-butyl-calix[4]arene-tetra-2-acetic-acid and p-tert-butyl-calix-[4]arene-di-2-acetic-acid-ethyl-ester) from an industrial pickling bath solution was studied. The pickling bath solution contained hydrofluoric and phosphoric acid as its main components. The aluminum removal was not successful and also no significant extraction of trace metals present was observed.

Jan 1, 1999

By Marcela C. Santini, Luiz A. Teixeira

"Surface conditioning (also referred as etching) of plastics prior to metallization is generally conducted with sulfuric I chromic acid solutions. Although these baths perform well technically, the presence of Cr (VI) imposes serious operating problems of an environmental nature. The present work reports ·the results of a study of surface conditioning o(ABS using solutions based. on sulfuric acid, with hydrogen peroxide and/or nitric acid, replacing chromic acid, as oxidants. Process performance was evaluated by SEM and by the uniformity and adherence of electroless nickel coatings applied on selected conditioned samples. The results showed that the evaluated types of solutions could be optimized to perform as well as the chromic-based baths, with a much superior environmental quality.IntroductionMetallization of plastics is normally undertaken for either decorative or functional purposes. Through metallization, the specific properties of plastics such as light weight, design flexibility, and low-cost of manufacturing are enhanced by the addition of properties usually associated with metals. These include reflectiveness, abrasion resistance, electrical conductivity, and a variety of decorative effects (1).The available processes that can be used for metallization of plastics are vacuum metallization or vapoµr deposition; indirect metallization and plating (1). Plating can be sub-divided into electroless plating and electroplating. In electroless plating, metal ions in aqueous solution are deposited on the .activated plastic surface by oxi-reduction reactions without the aid of an external electric potential, forming a thin metallic layer. This electroless deposited film has two functions: (a) it provides an electrically conductive substrate that allows further coating by electroplating; and (b) provides a secure bond between the plastic substrate and the electroplated layer (1,2). In case the electroless metallic part requires an additional layer for finishing purposes, or just an increase in thickness, the part can be additionally electroplated with a· variety of metals - in most cases those are copper, nickel or chromium (3)."

Jan 1, 2000

By C. W. Vierrether

Mineralogical analysis contributes directly to the selection of applicable beneficiation techniques for a given site. Tentative remediation methods for use on the Sharon Steel tailings in Midvale, Salt lake County, UT, were determined in part by mineralogical characterization. A systematic characterization scheme was employed to identify mineral species, mineral associations, and grain size. This paper presents the mineral content and distribution data collected for site characterization. This data was used to determine areas that were representative of the total tailings at the Sharon Steel site. Although this was the main focus of characterization, other useful information was obtained. The approximate location of "old jig tails" was identified and insight on possible arsenic, mobility through the pile was also obtained from the mineralogical study.

Jan 1, 1991

By S. Kang, D. G. C. Robertson

Slag cleaning furnaces require extensive wall cooling because they involve the use of a superheated slag bath. This is in direct contrast to smelting furnaces, where the wall is usually (but not always) protected by "banks" of solid charge. In order to understand the heat transfer and flow in slag cleaning furnaces a number of model studies have been carried out using molten wax to simulate the slag. Wax is a good model fluid because, like slag, it has a high Prandtl number. Wax models cannot simulate the behavior close to the electrodes (DC arc or AC submerged), but they can and do give a good simulation of the flow and heat transfer at the wall. An understanding of these phenomena is of great importance for the design of cooling panels in the walls of the furnace. Since superheated molten slag will eventually wear away any refractory bricks over time, the wall cooling must be designed to form a frozen layer of slag, referred to as a "freeze lining". The heat flux density (Q/A) required to do this is given by Q/A = h* ?T, where h is the heat transfer coefficient in the slag phase at the wall, and Li T is the superheat (bulk slag temperature - liquidus temperature). Both Q/A and h vary greatly with position and both are usually a maximum at the slag line. In the experimental work, molten wax baths were heated by block heaters to provide similar energy densities to those encountered in commercial slag cleaning furnaces. This procedure was considered to be valid since most of the electrical energy into a furnace bath is dissipated as heat. Gas stirring was used to simulate the gas evolved at the electrode in real furnaces - the quantity of this gas could be estimated from a knowledge of electrode consumption. The similarity criterion was equal gas flow per unit area of surface, in model and prototype. Heat transfer coefficients were measured in the models as a function of power density, gas stirring, superheat, etc., and could be related to the full-scale operations by the use of dimensional analysis.

Jan 1, 1999

By Shoji Taniguchi, Lifeng Zhang, Kaike Cai

"In the present paper, based on the two-phase (Eulerian-Eulerian) model, the 3D fluid flows in gas-stirred systems, i.e., air-stirred water vessel and argon-stirred liquid steel ladle, are simulated. In the Eulerian-Eulerian two-phase model, gas and liquid are considered to be two different continuous fields. The phases are assumed to share space in proportion to their volume fractions. The exchange between the phases is represented by source terms in conversation equations. Turbulence simulated by the k- e model is assumed to be the property of the liquid phase. The following effects of mathematical treatments and operational factors on the fluid flow are discussed, such as interphase drag force, turbulent model, the size of bubble, and gas injection mode.Some interesting results are derived. Except the interphase drag force, the interphase lift force should be taken into accounted in order to exactly simulate the fluid flow in gas-stirred systems. Suitable turbulent model and drag coefficient have effect on the mathematical simulation. Injecting small bubbles can realize a well mixing flow condition. The distance between the two gas-injection nozzles has effect on the fluid flow."

Jan 1, 2000

By P. A. Manohar

This paper describes an implementation of the Potts model for simulation of grain growth in 2D on a distributed-memory parallel architecture. The simulation scheme utilizes a continuous-time, asynchronous parallel version of the n-fold way algorithm. Each Processing Element (PE) carries a piece of the global simulation domain while the virtual topology of the PEs is in the form of a square grid in 2D and Torus in 3D. Different PEs have different local simulated times. Inter-processor communication is carried by the Message Passing Interface (MPI) routines. Sample results for grain growth simulation in 2D are presented for a 840 x 840 global domain size distributed over 16 PEs. The grain growth kinetics obtained in the simulation of pure, isotropic systems is in good agreement with the theory. Grain size distributions obtained in the parallel simulation are well described by the lognormal distribution, thus validating the simulation procedure. Keywords: Metropolis algorithm. n-fold way algorithm, asynchronous parallelization, grain growth

Jan 1, 2003

By Farouk Tedjar

The growth of miniaturization in one hand and energy density need lead to rapid development of new chemistry for batteries as observed during last decade particularly in secondary systems. However dark side of the progress is always in environment impact and scarcity of resources. In the lithium segment a jump from six electrochemical series (all non rechargeable systems) before 1990 to more than 15 systems including new rechargeable systems has been observe during last decade. Lithium battery chemistry was enriched with new electrolytes, conductive salts and new oxide composition. In the same time, lithium ion battery safety was strongly improved during last period. The progress of these technologies was strongly boosted by the substantial growth of the mobile telephone market in the mid 1990's (+ 1% a month in 2000, and a 71% penetration rate in Europe in 2005 compared to just a few percent in 1996). This market is constantly in search of higher electrochemical performance (mainly energy density in front of increasing miniaturization. Recycling of end of life product could be managed not only in environment aspect, but also under resource conservation and economic aspect of arising technology (mainly on the effect of re-injection recovered materials) The Li-ion segment is a new branch in the cobalt market and impact of LiCoOx will be fitted with the actual increase of the demand for this battery. For this reason all the processes aim to valorize active and packaging material. RECUPYL process project was conducted in this direction to offer a new solution for recycling those lithium systems. The process has been developed at pilot industrial scales using synergy between new equipment (for mechanical pre-treatment step) and existing line at RECUPYL facility (for chemical treatment) and should lead to high valorization rate with a minimum hazardous co-products. The process was also developed in order to be able to recover news cathode materials introduced in electrode like LiFEPO4, LiMxCoyO2 and new anode composition in substitution with former carbon anode.

Jan 1, 2006

By Bogidar Mihaylov

A laboratory study was conducted on continuous precipitation of copper, cadmium, mercury and arsenic using thiourea, thioacetamide, sodium sulfide and ammonium sulfide as precipitating agents. Depending on the experimental conditions the metals precipitate with the sulfide donors at different orders and rates. These differences were employed as a basis of several techniques for continuous separation of copper and arsenic, cadmium and arsenic, mercury and copper, and copper, mercury and arsenic. The separation of the metals from industrial waste solutions was also studied. The precipitates obtained were inspected using x-ray diffraction, scanning electron microscope, atomic absorption spectrometer and plasma particle counter.

Jan 1, 1992