Search Documents

By Xin Wang, Hongmin Zhu, Shuqiang Jiao

"The behavior of electrochemically depositing silicon in a molten high-melting-point fluoride electrolyte was studied at 1300 °C. The cathodic product was characterized by XRD, SEM and EDS. Though the analysis of structure and composition of deposition, it could certify that silicon deposited on the Mo rod and alloyed with molybdenum. A series of tests had been performed on the cathodic behavior of Si4+ ions in BaF 2-CaF 2-Na2S iF 6 molten salt. The influence of electrochemical parameters on the cathodic deposition of silicon was also investigated. The electrochemical behavior of Si4+ ions in applied fluoride melts was observed to proceed according to one-step reaction.IntroductionGreenhouse warming has been a serious global issue. lt is increasingly urgent for clean and renewable energy. Effective utilization of clean and inexhaustible solar energy has become very important. Solar cell (especially poly-Si solar cell) production has significantly increased this decade, as there is a growing demand for clean energy. Since the early 1980s, the annual growth of the photovoltaic (PY) solar cell industry is more than 30%. More than 90% of the annual solar cell production is based on crystalline silicon wafers. This rapid growth leads to a shortage of silicon of the adequate quality and price for the continued growth of this industry [I , 2J. The most conunonly used technology to produce silicon is the so-called Siemens process. This technology, involves the forming of gaseous Si compounds such as trichlorosilane (SiHCli) or silane (SiH4) with subsequent thermal decomposition of these back to Si. This technology is associated with transformations from solid to gas, and then back to solid phase, which lead to high irreversible thermodynamic losses and subsequent high energy consumption, the energy cost being around 200kWh/kg Si [3l_ The purity of the material from this process is very high (9 to 11 N). In general, what is needed for solar cell purposes are reported to require 4 to 6 N quality. To promote continued growth of the silicon-based PY industry, there is need for a low-energy silicon production process which can produce large amounts of silicon with an acceptable quality and a lower price particularly."

Jan 1, 2012

By Alicia E. Ares, Carlos E. Schvezov

In the present work it was observed the nucleation and growth of grains in the equiaxed zone of metal matrix composites (MMCs) samples directionally solidified wit the presence of columnarto- equiaxed transition (CET) in the samples. In order to do so, first, it was defined the difference between the real temperature at a given instant, which it is used in the analysis, its variation and furthermore, the variation in the solid fraction with time between the beginning and the end of solidification. It was determined a growth law assuming a lineal variation of equiaxed grain radius as a function of time, and also, it was expressed a law of grain density as a function of time, considering the presence of SiC and Al2O3 particles in the matrix. Finally, the results obtained were validated with measured values of grain density at each position of the thermocouples in the equiaxed zone of the solidified samples.

Jan 1, 2015

By Juergen Antrekowitsch, Stephan R. Steinacker

The main aim of the electric furnace treatment in the primary copper industry is the reduction of valuable metals such as zinc, lead or copper itself. On the one hand legal restrictions for the further use of the treated slag are constantly getting stricter while on the other every type of loss in the oxidic phase leads to economic disadvantages. In order to fully understand and to improve the process, kinetics during the reduction play an essential role. In the first part, this paper highlights the theoretical background of the reduction process, while the following chapters present experimental aspects and results from laboratory scale trials at the Montanuniversitaet Leoben. In addition, the comparison between the chemical reaction and the diffusion model plays a continuously important role. By investigating the reducibility of electric furnace slag, process adaptions and ameliorations are developed.

Jan 1, 2016

By Tracy Morris, Weldon Read, Luis Navarro

"Bismuth is a recognized contaminant in the electrolytic refining of copper that can render many cathodes to be outside ASTM standards and unsuitable for copper rod and other downstream products if not carefully controlled. This paper portrays the performance of Molecular Recognition Technology (MRT) for bismuth removal at the Amarillo Copper Refinery (ACR) and describes how the highly selectivity gel has been successfully used to achieve good bismuth removal and how many pit falls and draw backs have been overcome.IntroductionASARCO operates one of the largest copper refineries in the world at Amarillo, Texas. The main feed for this refinery is produced at the Hayden smelter in Arizona. During the operation of this smelter a variety of metals are carried as impurities in the copper anodes because of the diversity of concentrates and residue products used as raw materials in the smelter feed mix. Even though the impurities are concentrated enough to be detected at the smelter, it is difficult to remove them completely. A simple way to control impurities at the smelter is to minimize the addition of material with a high concentration of impurities to the charge in order to reduce the output of this metal species. All this leads us to have a ""refinery problem"" [1,2,3]."

Jan 1, 2012

By Enrique Posada

"The Valle de Aburrá area, corresponds to the city of Medellín and neighboring municipalities, with more than 3 million people. The area generates a sizable amount of solid waste, which has been taken to landfills for the last 20 years. This paper proposes a model for public policy making which considers the cost and benefit of different alternatives to handle the wastes in the coming 20 years. Combinations of several alternatives: Recycling, waste reduction, waste separation, incineration, land filling with lixiviate treating and gas energy recovery, and organic waste composting are considered and modeled and the results presented as a contribution for a more rational approach to policy making than the one currently being employed.IntroductionThe author, working for INDISA S.A., acted as a consultant for the direction of planning of the Empresas Varias de Medellín in 2004. This entity has the responsibility for the handling of the solid wastes of the city of Medellín and some of the neighboring municipalities. At the present time more the 700.000 annual tons of waste are taken to the site of La Pradera, located in very rainy location (3.000 mm of precipitation per year), with complex in topography and very far away from the sources of the waste. During the work the author detected important problems that should be addressed, as follows:Lack of adequate technical administration and resources. The entity did not count with sufficient human resources to focus on the appropriate technical handling of the solid waste. The organization worked mostly with independent contractors, lacking enough coherence and integration. The internal workload was too large for the few people who had technical responsibility and this gave rise to attention problems. It is important to have clear technical procedures, technical know how and human resources, continuity in the activities. It is important to have a clear capacity to plan, to study, to make tests and monitoring, to pursuit and develop ideas, to optimize the processes and to introduce changes, to respond to environmental authorities, to the communities and to mass media and to handle the contractors. All this was basically lacking. In the case of the handling of the sanitary filling of La Pradera, for example, although the people in charge were very able and dedicated, the magnitude of the task was too large and the resources they had were insufficient. As a result, the site had at the time of the study, problems with thousands of vultures, lack of immediate cover up for the waste, uncontrolled leaching, the area being dirty and little attractive, despite being called a park."

Jan 1, 2008

By Versiane A. Leão

The hydrochloric leaching of chrysotile tailings and soapstone powders) is discussed. This two materials are magnesium compounds associated with carbonates and iron oxides. In this work the chemical and physical characterization of formers is presented and the thermodynamic analyses of leaching is carried out. Magnesium extraction is almost complete for chrysotile tailings while, for soapstone powders, one can be reached 60%. The behavior of iron and calcium impurities is discussed.

Jan 1, 1997

By Yukihito Sasaki

Sumitomo Metal Mining Co. Ltd. planned an expansion program for the Toyo smelter and refinery in order to increase the production capacity of electrolytic copper to 450,000 tpy in 2007. Regarding the flash smelting furnace, a drastic increase in the average concentrate smelting capacity from 2,300 tpd to 3,950 tpd was required to achieve the plan. It was necessary to examine the performance of the Sumitomo concentrate burner when the feed rate was considerably increased. The authors developed a mathematical model to describe the combustion phenomena in the Toyo flash smelting furnace. This model was developed incorporating the fluid flow, heat and mass transfer, and chemical reactions of the copper concentrate and ancillary fuel. The copper concentrate was considered to mainly comprise chalcopyrite (CuFeS2). The reaction of CuFeS2 was assumed to consist of two steps, namely, the decomposition of CuFeS2 and the oxidation of the resulting pyrrhotite (FeS) and sulfur (S). The combustion phenomena in the furnace at the increased feed rate were predicted using this model. It was found that the Sumitomo burner was capable of enhancing the smelting capacity. This is attributed to the wide dispersion of the concentrate particles caused by an increase in the particle mass and a long residence time in the reaction shaft; this is due to the low temperature of the reaction air. However nonuniformity of the reaction in the reaction shaft was enhanced with the increased feed rate. In order to improve the nonuniformity of the reaction, an increase in oil-burner oxygen and an enlargement of the diameter of the dispersing cone were useful. By combining the expertise of the Toyo smelter staff and the calculation results, the concentrate smelting capacity of the Toyo smelter has been stably increased to 3,600 tpd thus far, and further improvements of the smelting performance are still being carried out.

Jan 1, 2006

By William Petruk

A mineralogical and image analysis study was conducted on samples of U tailings from pilot-plant runs on Midwest ore in Northern Saskatchewan. The tailings had been subjected to simulated weathering for the equivalent of 10 years in a tailings facility (lysimeter). The pH varied from 7.0 at the beginning of the test to 5.9 at the end. The results show that during the simulated weathering sane of the gersdorffite, uraninite, galena and pyrite had oxidized, with gersdorffite being the most reactive and pyrite the least. Reaction was evident at the top of the lysilleter , but was most intense at the seepage discharge. sane of the released ions precipitated as Ni, Pb, and U arsenates, sulfarsenates, sulfates and oxides on particles of all minerals. Green crystals of Ni sulfate and white crystals of ca sulfate had precipitated at the surface of the lysilleter. Clay minerals and chlorite had washed from the top of the lysirneter towards the seepage discharge.

Jan 1, 1989

By Anurag Tripathi, J. K. Saha, S. K. Ajmani, J. B. Singh

"The quality of steel is a major concern in the metallurgical industry. The control of liquid steel temperature can enhance the level of cleanliness in steel. Ladle is one of the major vessels used to transfer liquid steel between different stations. The heat transfer phenomenon taking place in this vessel needs to be monitored for controlling the liquid steel temperature. A CFD model was developed for prediction of liquid steel temperature during complete process cycle of ladles in direct heats. The model was validated with liquid steel temperature measured at on-line purging station and tundish during teeming from one of the actual steel plant. The accuracy of model was 96 %. The results obtained show insignificant effect of slag thickness, tapping temperature and ladle life on liquid steel temperature in the ladle. However, the importance of initial refractory temperature was noticed. The CFD model developed in present work can generate the thermal history of liquid steel and refractory walls of any ladle at any stage.1. IntroductionThe control of liquid steel temperature is desired to achieve required steel quality. The low casting temperature is detrimental and may result in nozzle blockages due to premature solidification in the tundish. The phenomenon of heat losses taking place in ladles needs to be understood for prediction of liquid steel temperature. The assessment of thermal profile of liquid steel from BOF converter to caster can be done through consideration of heat losses at all points. Hlinka and Miller [1] showed that the ladle pouring temperature varies due to heat losses from molten steel into surrounding refractory layers. The phenomenon of thermal stratification was numerically simulated by Ilegbusi and Szekeley [2]. The effects of slag cover on heat loss and liquid steel flow in ladle before and during teeming to a continuous casting tundish was numerically simulated by Chakraborty and Sahai [3]. Investigators also developed some simple models to predict the steel temperature for some of the processes taking place in ladles [4-9].The present work is an effort to generate the full information about the temperature drop taking place in any ladle throughout its process cycle. This information can be used to predict liquid steel temperature and to take decisions to minimize heat losses."

Jan 1, 2012

By Celaletdin Ergun, Ibrahim Erden, Gurbuz Gunes, Thomas J. Webste, Huinan Liu, Abdurrahman Bahadll

"B, Ti, Ag, AI and Cu substituted hydroxyl apatites were synthesized via precipitation method. Then the samples were air-sintered at 1300°C for 2 hrs and characterized with XRD, SEM, FTIR, and cell adhesion behaviors.IntroductionSynthetic hydroxylapatite (HA, Ca10(P04)6(0H)2) has a similar composition and structure to biological apatite. Therefore, it has been safely and extensively used as an implant material for bone substitute. However, synthetic HA has been used for a various applications including medical or non-medical applications, such as matrices for drug release control, bone cements, tooth paste additive, blood purification agent, monolithic implants or coatings on metallic implants, packing media for column chromatography, gas sensors, catalysis and host materials for lasers and luminescent materials, etc. [1-9].The major factors affecting the performance of HA on these applications are crystal morphology, density, porosity, pore size and distribution, chemical composition, and surface structure. As provided by the high flexibility of the apatite structure a great variety of cationic and anionic species can be substituted into HA structure which is specifically considered as an effective method to modify the properties of HA [10,11]."

Jan 1, 2012

By Ruhi Bux, Akshay Verma, Mohini Saxena, P. Asokan

"Due to the colossal increment in the industrialization, the generation of wastes gathered as a result of different extraction, benefaction and generation processes is having an alarming problem for waste disposal. The best and most acceptable way is to use the waste in accordance to its potential for the generation of high value lucrative composite goods. The study in this paper elucidates the potential of several industrial wastes like fly ash, red mud and marble slurry dust for the production of different wood substitute products like doors, windows, roofing sheets and instant houses for the rehabilitation on the sites of catastrophes. Wastes were initially characterized for the physical, chemical and mineralogical properties and then used in different formulations with binder like Polymer along with natural fiber like Jute to intensify the physical as well as mechanical properties of the resultant composite. The study also reveals that these composites have better mechanical properties than the available ones like teak, medium density board, Rice husk board etc. Also, the fly ash and red mud composites have better mechanical properties than marble slurry based composites. The results fosters the implementation of natural fiber with the industrial waste in the generation of eco-friendly and non-hazardous composites.IntroductionOver the last few decades, there has been a tremendous increase in the generation of industrial wastes gathered as a result of various extractions, benefaction and generation processes. The condition worsens even, when it comes to high quantum generated wastes like Fly ash, Red mud and Marble slurry dust. The primordial motif behind the incorporation of industrial wastes as filler in the development of composites is primarily composed of two main objectives; Firstly waste management, the colossal waste dissemination in the environment has disturbed the ecological balance by polluting land, surface water, ground water, air, natural resources and even disturbing the public health [1]. Secondly, to act as a perfect substitute for the conventionally existing building materials, this will aid in dwelling places to many with the least incorporation of exhaustive natural resources as woods quid pro quo."

Jan 1, 2008

By Tiffany Brown

In the thiosulfate gold leaching process, thiosulfate is used to complex gold following electrocatalytic oxidation of the native metal by Cu(II)-ammines. Unfortunately, Cu(II) complexes also catalyse the undesirable conversion of thiosulfate to polythionates. We have been seeking alternatives to ammonia, which fulfil the role of ammonia but minimize thiosulfate decomposition. One aspect of these studies has involved the determination of the rate of thiosulfate oxidation by the Cu(II) complexes from UV-Visible spectral changes. Various ligand classes, including pyridyls, polyamines, aminocarboxylates and picolinates, have been tested and the majority found to inhibit thiosulfate decomposition. Interesting variations in reactivity with the nature and denticity of the ligand and L/M ratio have been observed. In the case of open chain polyamine ligands with 2 to 5 nitrogen donors, the rate of thiosulfate oxidation was generally found to decrease with the denticity and the concentration of each ligand. Saturation of the Cu(II) coordination sphere appears to inhibit the oxidation of thiosulfate when excess thiosulfate is present. The Cu(II) complex of the branched polyamine ligand, tris(2-aminoethyl)amine (tren) exhibits this behaviour in excess thiosulfate. Interestingly, when the [Cu(tren)(OH2)]2+ complex is in excess oxidation of thiosulfate was observed. This unexpected finding prompted a spectrophotometric study of this reaction which has revealed that the oxidation of thiosulfate involves several processes, two of which involve the formation and decay of a tetrathionate radical.

Jan 1, 2003

By Tim J. A. Smith

Fundicion Refimet S.A. has operated a custom copper smelter at La Negra, near Antofagasta in northern Chile since 1993. From an initial operation based on Reverb smelting and Peirce-Smith, converting, the plant was expanded from 90 000 t/y to 160 000 t/y copper production in early 1997, by conversion to oxy-fuel smelting and use of concentrate injection on Converters. As part of this expansion a novel reverb gas cooling and cleaning system was developed and designed by Kilborn SNC-Lavalin Europe, the London, UK-based mining and metals; Office of Canada's SNC-Lavalin group. The reverb gas cooler needed to satisfy several very specific requirements including low cost, flexibility, robustness and simplicity of operation. Of particular importance was the requirement to cool and clean the ,oxy-fuel reverb gases and render them suitable for subsequent treatment in a conventional sulphuric acid plant. It was also important to avoid accretion or dust handling problems. This paper describes the key design features and subsequent successful installation, commissioning and operation of the unit.

Jan 1, 1998

By Jesse White, Arlin Olson

"An Engineering Scale Technology Demonstration (ESTD) unit utilizing the THOR fluidized bed steam reforming technology was built and operated by Hazen Research, Inc. for the purpose of denitrating and solidifying various Department of Energy (DOE) radioactive tank waste surrogates into granular products. The ESTD offered the opportunity to investigate the operational characteristics of two fluidized beds in series to test process system designs such as those for fluidization, feeding, and product collection. Operational characteristics that were evaluated included bed attrition rate, particle growth, and elutriation; and the effects that variations in process parameters (e.g., fluidizing gas flow rate, feed composition, feed injection method, and gas distributor design) had upon these characteristics were observed. Testing of the process systems on this scale allowed for design changes to be made where the cost in time and money were significantly less by comparison to those same modifications being made on the commercial scale.IntroductionFluidized bed steam reforming (FBSR) offers a moderate temperature (620-750°C) continuous method by which various liquid wastes can be processed irrespective of whether they contain organics, nitrates, sulfates/sulfides, chlorides, fluorides, volatile radionuclides or other aqueous components. The FBSR technology has exhibited the potential to process these wastes into either a carbonate or crystalline ceramic (mineral) granular product.Pilot scale testing was performed using the THOR Treatment Technologies, LLC (ITT) FBSR process, as it offered the opportunity to evaluate multiple aspects in an environment more conducive to experimentation. Process changes and system modifications could be made faster and with less cost impact as compared with changes to an assembled commercial plant. These aspects include verification of process chemistry and kinetics, evaluation of materials of construction, equipment sizing and design, and the interactions of the systems. Evaluation of process chemistry allowed for the verification of thermodynamic and kinetic models, and was used in conjunction with these models to improve the database and modeling assumptions. It also allowed for the reevaluation of data from earlier bench scale testing with the opportunity for long-term operations. These long-term effects may include the buildup of one or more elements that results in the formation of eutectics leading to the destabilization of a fluidized bed, or the shift in particle size as a result of attrition or agglomeration. The pilot plant also provided an environment to evaluate materials of construction."

Jan 1, 2014

By Rumen Markov, Lubomir Kuzev

"The treatment technologies for municipal solid waste (MSW) are effective mainly for components sized over 40 – 50 mm. This fraction is separated by screening in the beginning of the process. Usually the undersized product is deposited without additional treatment. Its quantity is variable from several up to 30 – 40 % of the total MSW. Both oversized and undersized fractions are formed by all types of primary matter. Adapted technologies from mineral processing will provide a suitable technology for treatment of MSW under 40 – 50 mm. The MSW content depends on the geographical location, the degree of urbanization and other factors. The methods can be applied for separations of different components suitable for recycling or other utilization are: • Separation by density; • Separation in thin liquid layer; • Selective grinding and screening; • Flotation, etc. Introduction Municipal solid waste (MSW) represents an integral part of public urbanization. However, there are some drawbacks stemming from MSW, in regard to its collection, transport and elimination. Different approaches exits worldwide for tackling the problems arising from MSW. For a short period of time, the attitude towards MSW has evolved in several levels, each further level being characterized by higher percentage of utilization of MSW components. Thus, the bottom line has been shifted from safety storage towards processing that includes recycling and maximal utilization of MSW components. Technologic processes applied for treatment of MSW have a common feature – that the fine components, having sizes under 20 mm, 30 mm, 40 mm, or 50 mm are excluded from treatment process trough screening, and in most cases diverted without any additional treatment to preliminary prepared storage sites. MSW in Sofia – current situation The amount of MSW collected daily in Sofia as around 1000 t/24 h. It is stored or baled. Baling is a spare alternative of storage, since baling insures only temporal keeping of MSW, till the building of suitable storage site where the bales will be transported and buried. The morphologic composition of MSW in Sofia has been determined several times at different time intervals, from some Bulgarian organizations as well as from the Japanese organization JICA. So far, however, there is still a lack of enough systematical and comprehensive study. Generalized results from the studies on the MSW components, as well as some important parameters are given in Table 1."

Jan 1, 2008

By Tracy Morris, Weldon Read, Luis Navarro

"During the leaching of anodic slimes, tellurium dissolves into the leach liquor together with copper and must be removed before the solution is sent to liberator cells for copper recovery. Prior to the installation of autoclaves, tellurium was precipitated using raw slimes that caused a recirculation of tellurium in the leaching circuit. After autoclaves were installed the old leach tanks were converted into tellurium reactors utilizing copper chips, steam and agitation to form a copper telluride precipitate. Tellurium levels of less than 10 rng/L are achieved in a timely manner.IntroductionThe electrolytic refining of copper consists of an electrolytic cell provided with an anode of impure copper, a cathode of substantially pure copper (starter sheet) and an electrolyte made of copper sulfate and sulfuric acid [1]. When a direct electrical current is passed between the anode and cathode inside the cell, the impure copper anode dissolves in the electrolyte and pure copper is plated onto the cathode. During this operation, many of the impurities are deposited on the bottom of the cell as an anodic slime residue composed of insoluble chemical compounds. Slimes are a major source of rare and precious metals in the copper industry [2-5],In the Amarillo Copper Refinery (ACR), the anodic copper slimes are sent to the Precious Metals department in order to extract and then refine the gold, silver, platinum and palladium from them. The remaining impurities, in the form of a soda slag or copper slag are sent to the Hayden smelter for further processing. Copper telluride is sent to the Selenium/Tellurium department inside the plant for selenium and tellurium recovery. During the leaching process of the anodic slimes, copper, tellurium, and other metal species in the slimes are dissolved into leach liquor that cannot be returned to the tankhouse unless the tellurium concentration is below 10 mg/L."

Jan 1, 2012

By Andrey Dmitriev

The solution of set of equations for the bottom zone presented by a condition of a thermodynamic equilibrium, namely, an equilibrium constant of wustite reduction by carbon oxide, material and thermal the balances, supplemented by the equation of the heat balance for the top zone, allows to calculate the base indices of blast furnace smelting. The calculated indices are extreme accessible at the given parameters of charge and blast. Application of actual degrees of the use of gas instead of equilibrium allows the calculations of actual indices of the blast furnace smelting process.

Jan 1, 2006

By Seung-Whee Rhee

Characteristics of ceramic support made by spent foundry sand-loess mixtures are investigated by bulk density, porosity, durability, and compressive strength. And the basic properties of SFS and loess are estimated. The effect of drying time after cutting process, elevated temperature time, sintering temperature, and sintering time is also estimated to obtain the optimal condition in the process of manufacture ceramic supports. From the basic properties of SFS and loess, the content of SiO2 in furan sand is much higher than that in loess but the content of Al2O3and Fe2O3 in furan sand is much lower than that in loess. In order to make ceramic supports cylinder shape is the most desirable to sustain the properties of ceramic support. If annulus shape has a enough compressive strength, however, annulus shape may be decided. For the optimal condition to manufacture ceramic supports, drying time after cutting process is decided to 24 hrs and elevated temperature time is decided by 9hrs. And sintering temperature and sintering time are decided to 900 and 9hrs, respectively in order to prevent solidification of sand materials.

Jan 1, 2006

By F. Begazo

The most common approach to increase production in copper refineries is to increase current densities. However, if these increases are not well thought out beforehand and are not properly and effectively controlled, the end results could be reduced plant performance and a deterioration in cathode quality. Both of these factors result in lower efficiencies and increased costs. At the Ilo Refinery of Southern Peru Copper Corporation, a modernization and expansion program was implemented shortly after the Refinery was purchased from Minero Peru, in 1994. This program was intended to increase production from 195,200 mtpy of cathode to 227,000 mtpy over a 3-year period. Part of this production increase would come from increasing current density. During the period from 1994 to 1997, current density at the Ilo Refinery was increased from 218 A/m2 to 230 A/m2, while plant efficiencies were maintained at consistently high levels. The current efficiencies were maintained at >97.5% and time efficiencies were maintained at >98%. During 1998, additional increases in current density were implemented while the high plant performance was maintained at the same levels. By the end of 1998, the current density was 241 A/m2, while current efficiency and time efficiency of 98% were maintained. This paper describes the control processes used at the Ilo Refinery to maintain high plant performance levels while increasing the current density. Additionally, expected plant performances from extended test programs at current densities up to 280 A/m2, for future production increases, are reviewed and discussed.

Jan 1, 1999

By Issa S. AI-Kharusy

Oxidation/reduction (REDOX) alloy media, as used in wastewater treatment, is founded on the exchange of electrons. Because of this electron exchange, many contaminants are converted to harmless components which require no further treatment. Other types of contaminants are removed from the waste stream by electrochemically bonding to the alloy medium. This paper discusses the REDOX reactions, the role of the alloy medium in various treatment processes, and describes specific applications of REDOX alloy media for the removal and minimization of waste. The characteristics and handling of spent treatment media is also reviewed as a further consideration in waste minimization.

Jan 1, 1996