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By Pierre-François Bareel

EU legislation imposes ambitious recycling targets for various consumer goods. End-of-Life Vehicles (ELVs), scrap iron and various proportions of Waste Electrical and Electronic Equipment (WEEE) are processed by shredding plants which recover most of the metals but produce Shredder Residues (SR) which are landfilled. They represent 20 to 25 wt.% of the shredder input. Energy issues for the coarse fraction of SR are now largely studied. However, below 2 mm, the calorific value falls off drastically. These Fine Shredder Residues (FSR) represent up to 55 wt.% of the total SR. To meet European objectives other alternatives to landfilling must be considered for the FSR. The present paper describes a study carried out to characterise the FSR and investigates ways to process them and produce marketable products. Applying Gy's theory, a sampling procedure was conducted over two years to statistically quantify the variability of the physical and chemical properties of FSR produced by a Belgian post-shredding treatment plant. Macroscopic characterisation has led to the identification of four material categories which could be separated according to their physical properties: ferrous metals (more or less oxidised), non-ferrous metals, an organic fraction (plastics, rubber, textiles, foams, wood) and a minerals fraction (glass, ceramic, concrete). The entrainment of small metallic particles within the pores of organic fragments will affect the quality of the separations.

Jan 1, 2006

By Sung Jin Han

Magnesia-based refractory is generally used in an electric arc furnace (EAF) due to its relatively high corrosion resistance and strength at high temperatures. However, the magnesia refractory is attacked by EAF slag and thus the lining life continuously decreases. Thus, it is significant to identify the interfacial reaction between magnesia refractory and FeO-rich EAF slags. In the present study, the influence of FeO-rich slag on the corrosion behavior of MgO refractory was evaluated. The (Fe,Mg)Oss layer was observed at the slag-refractory interface and its thickness increased with increasing content of FeO in the slag. The specific reaction phenomena and formation behavior of (Fe,Mg)Oss layer were evaluated by thermochemical computing program, FactsageTM7.0.

By Dale T. Peters

In the United States, the United Kingdom and numerous other countries, copper has long been the plumbing material of choice. This has been the case since the late 1920s in the United States and since World War II in the United Kingdom. However, in recent years the plumbing tube market has caught the eye of the chemical industry, and several plastic resins have been introduced to the marketplace as substitutes for copper in household plumbing systems. One of these, polybutylene tube, had so many failures in the United States that a class action law suit was filed, and the manufactures of this product were forced to create a trust fund of nearly one billion dollars to repair damages caused by their product. Chlorinated polyvinylchloride (CPVC), in rigid pipe form, on the other hand, has been mechanically acceptable albeit its recent introduction precludes the test of time enjoyed by copper tube in this application. This paper reviews the State of California's portrayal of copper's environmental effects and will be largely based on the data and information assembled by the Copper Development Association Inc. in its presentation to the State of California in August, 1998 in response to the State's Draft Environmental Impact Report for Chlorinated Polyvinyl Chloride (CVPC) Pipe for Use for Potable Water Piping in Residential Buildings. The paper is intended for use as a model for the use of other copper organizations and individuals in responding to similar situations.

Jan 1, 1999

By Brandon R. Ball

An investigation of the effects of ozone and ozone-induced hydroxyl radical on reducing whole effluent toxicity is described and discussed relative to the application of ozone for industrial water treatment. Results from operation of an ozone system treating industrial effluent from a lead and zinc mine in Colorado are presented. The mine discharges 1,000 gpm of wastewater into a tributary of the Arkansas River and has historically exceeded Whole Effluent Toxicity (WET) limits and on occasion has exceeded numeric limits for copper, ammonia, and cyanide. Based on results of a Toxicity Identification Evaluation (TIE) conducted on the effluent and individual process waste streams, the source of effluent toxicity is believed to be primarily associated with organic reagents used in the milling process. Based on test results, an applied ozone to COD ratio of 3: 1 by weight and a contact time of 30 minutes was found to be effective for reducing whole effluent toxicity at pH 11 but not at pH 7, indicating oxidation by hydroxyl radical to be the dominant mechanism responsible for toxic-ity reduction. At an applied ozone to COD ratio of 3:1 and a pH of 11, toxicity was improved from 0 percent survival to 100 percent survival for Ceriodaphnia dubia and fathead minnow (Pimephales promelas) based

Jan 1, 1996

By R. Padilla, M. C. Ruiz, R. Villa

"Bismuth is an impurity in copper minerals where it occurs mainly as the mineral bismuthinite (Bi2S3). In smelting of copper minerals, most of the bismuth reports to the white metal, as a result, a substantial amount of bismuth accompanies the copper to the electrorefined cathodes. Thus understanding the behavior of Bi2S3 at high temperatures is crucial to eliminate bismuth before electrorefining. In this paper, some experimental data on the decomposition/volatilization of bismuthinite in nitrogen- oxygen atmospheres is discussed. The results indicated that in nitrogen atmosphere, bismuth volatilization occurs through a fast decomposition of bismuthinite to metallic bismuth and sulfur with subsequent volatilization of bismuth in the range 850-1100 °C. Similarly, in the presence of oxygen, bismuthinite decomposes to bismuth too, followed by oxidation to the non-volatile bismuth trioxide at temperatures higher than 750 °C. Both, temperature and partial pressure of oxygen affect significantly the bismuth volatilization and the oxidation rates.IntroductionCopper sulfide minerals are the major source for the production of metallic copper by pyrometallurgical processes, which are the dominant processes in the production of copper by selectively oxidizing the sulfide sulfur to SO2 and the accompanying iron in the concentrates to iron oxide, which can be conveniently removed as a stable slag.Generally, copper concentrates contain some deleterious minor elements such as arsenic, antimony, bismuth and lead, which are present as sulfides. These elements depending on their concentration may originate problems in the copper smelting processes and they can ultimately lead to a final copper product with unacceptable high levels of impurities.During the treatment of these copper concentrates by smelting, the impurities generally distribute themselves in the condensed and gas phases and they are eliminated mainly through the gas phase [1-3]. Thus, smelter off gases contains substantial amounts of volatilized impurity elements. For example, in the case of bismuth, the estimated distribution of bismuth in flash furnace smelting [2] was 15 % in the matte, 5 % in the slag and 80 % in the gas phase, and recently, for Outokumpu flash smelting Davenport [3] reported the distribution of bismuth as 30-75% in matte, 5-30% in slag and 15 -65 % in the off gas."

Jan 1, 2011

By Paul O. Malan

"The Tusc gold deposit is located along the Carlin Trend approximately 13 kilometers north of Carlin, Nevada and 2.5 kilometers northwest of the Gold Quarry mine. Tusc is one of several structurally controlled oxide gold deposits located along the Good Hope fault within the Maggie Creek subdistrict. Mining commenced in 1994 with an oxide reserve of780,000 troy ounces of gold at an average grade of 1.34 g/t Au. The Good Hope fault forms the southwestern edge of the Schroeder Mountain uplift (also known as the Carlin Window) and juxtaposes carbonate rocks of the Siluro-Devonian Roberts Mountains Formation against siliceous mudstone, siltstone, and silty limestone of the Devonian Rodeo Creek unit. Submicroscopic gold mineralization is disseminated in the Good Hope fault system and in fractured hanging wall carbonate rocks. Wallrock alteration includes silicification, deca!cification, sericitization, and late alunite replacement and veins. All Tusc ore is transported 2.5 kilometers to Gold Quarry for processing. Leach-grade ore (0.2 - 1.7 g/t gold) is placed on the oxide leach pads, and mill-grade ore(> 1.7 g/t gold) is processed through the CIL oxide mill. IntroductionThe Tusc gold deposit is located in Eureka County, Nevada, U.S. A, approximately 13 kilometers north of the town of Carlin and 2.5 kilometers northwest of the Gold Quarry mine (Fig. 1 ). Tusc is one of several open-pit, oxide, gold deposits within the Maggie Creek subdistrict of the Carlin Trend. Tusc is a structurally controlled gold deposit located along the Good Hope fault. Submicroscopic gold mineralization is disseminated in the brecciated and silicified Good Hope fault zone and along intersecting northeast and northwest striking structures."

Jan 1, 1997

By R. K. Hill

The Hidalgo Smelter successfully reduced operating costs by 25% compared to the previous two years through a focused holistic approach to development of its entire workforce. The first phase involved basic team training skills for natural work teams. The second phase provided leadership training via breakthrough education to 40 of the smelter leader-both hourly and salaried. The third phase stretched out the teams training to include rewards for performance that resulted in hourly teams converting to salaried status-part of a company wide initiative. The fourth phase saw 1998 become the "Year of Safe Cost Reduction" where 7 breakthrough projects focused on different areas of expenditure. Implementation of lean manufacturing as a tool for teams to truly get their arms around what they controlled, introduced accountability and responsibility for operating results at the team level. This will allow the release of experienced supervisors from this role, to a pool of technical expertise, where our future breakthroughs will be designed and implemented.

Jan 1, 1999

By Norbert L. Piret

During smelting of copper, arsenic in the feed reports to a large extent to the gas phase and some enters the anode copper. From the gas phase it is transferred during wet gas cleaning directly, or indirectly after dust processing, to aqueous solution. During the electrorefining and anode slimes processing, the anode arsenic content is also transferred to aqueous solution. Technology for the efficient removal of arsenic from process streams and cleaning of aqueous effluents is well established. However, the arsenic-bearing products, which thereby are generated, can vary widely in consistency, quality and quantity, from large amounts of gypsum contaminated with water-soluble arsenic compounds to residues with high arsenic content ' or arsenic products. Arsenic management in a copper smelter not only is involved with the duty of compliance to the gaseous and aqueous emissions standards but also should have as objective the minimization of the generation of arsenic-bearing and, in general, heavy metal-bearing solid waste. The present paper outlines options and the associated economic aspects for minimization of arsenic-bearing solid waste generation, for improvement of the environmental compatibility of the residues to be deposited and for the .production of commerciable arsenic compounds under appropriate market conditions.

Jan 1, 1999

By Corby G. Anderson

Laboratory testing, interpretation and application of metallurgical technologies can be tedious, time consuming and costly. This paper outlines the use of proven statistical design of experimentation software for rapid optimization of laboratory testing and operating plants with limited representative sample utilization. This results in less costly required testing, a more thorough understanding of results and the ability to simultaneously optimize several variables and outcomes at once. At the Center for Advanced Mineral and Metallurgical Processing, this testing methodology has been used successfully in many metallurgical development and plant optimization projects thereby confirming its real world utility and application. Accordingly, several applied examples in flotation and hydrometallurgy will be outlined in this paper. This will include flotation testing of a copper gold ore, flotation testing of a copper, cobalt and gold ore, optimization of an industrial hydrometallurgical jarosite circuit and optimization of industrial nitrogen species catalyzed pressure leaching of a copper enargite concentrate.

Jan 1, 2006

By Liang Wang, Sheng-Kai An, Bing Xie, Hong-Yi Li, Cui Li

In order to develop an environment-friendly method for extracting vanadium effectively from aqueous solution containing vanadium, the dynamic adsorption behavior of V by a continuous fixed-bed column which was filled with macro-porous weak base anion exchange resin was studied. Effects of conditions including the bed depth, flow rate, concentration of vanadium ions on dynamic V adsorption were investigated. The optimum adsorption conditions were established at flow rate of 6 ml/min with bed depth of 20 cm. Isotherms studies demonstrated that the column adsorption of V was a favorable chemical ion exchange process in monolayer. Several kinetic models were applied to analyze the adsorption characteristics. Analysis results of the Bohart-Adams model indicated that the adsorption process was dominated by external mass transfer in the initial stage. The Thomas model was appropriate to describe the column behavior, revealing that both external and internal diffusions were involved in the limiting steps.

Jan 1, 2014

By W. C. Chang

Phases and magnetic evolutions of melt spun Nd9.5(Fe1-xCox)85.5B5 (x=0, 0.05, 0.1 and 0.15), (Nd1-yLay)9.5Fe85.5B5 (y=0, 0.0.5, 0.1; and 0.15) and (Nd0.95La0.05)9.5(Fe1-zCrz)81.5B9 (z=0, 0.033, 0.067 and 0.1) nanocomposites: have been investigated. It was found that a. dilute Co substitution for Fe, x=0:05-0:15, in Nd9.5(Fe1-xCox) 85.5B5 improved not only Curie temperature but also the remanence and maximum energy product. Partial substitution of La for Nd in(Nd1-yLay)9.5Fe85.5B5 may suppress the grain growth of the materials during thermal treatment. Exchange coupling between the Nd2Fe14B and a-Fe was found: to increase with increasing La content. A dilute La-substitution, y=O. 10, has proven to decrease the optimum wheel speed required for preparing melt spun ribbons with better magnetic properties; Furthermore; a slight substitution of La for Nd in (Nd0.95La0.05)9.5(Fe1-xCrx)81.5B9 nanocomposite reduced the crystallization temperature of the over-quenched ribbons and led to the formation of a multiple phases mixture. Nevertheless, a dilute Cr addition increases the Tg of (Nd0.95La0.05)9.5(Fe1zCrz)81.5B9 and also suppresses the formation of the undesired (Nd,La)2Fe23B3 and Fe3B phases: Cr was found to play an important role in grain smoothening or magnetic separation which consequently increased the Hc of Cr-containing materials.

Jan 1, 1997

By Georgina De Micco

The National Commission of Atomic Energy is investigating a suitable physicochemical process for the conditioning of spent nuclear fuel and treatment of the scrap of research reactors of the Al-UxSiy type. A possible way of processing is through dry chlorination of the cladding with the purpose of selective separation of the aluminium from the remaining elements such as Fe, Ni, Zn, Cu, etc. transforming them into volatile chlorides. Some important advantages of this method are the thermal stability of the chlorides that allow the easy separation of the halides by physical methods and the low volume of radioactive waste generated. The interactions in the following systems were studied in the range of temperature between 150º-500°C: Al-Fe, Al-Ni, Al-Cu, Al-Zn, Cu-Zn and the pure metals. We found that the reactivity was different depending on if the elements were alloyed or separated. The separation factors of the systems under study were determined. Nickel is perfectly separated from aluminium for all temperatures, whereas good conditions for copper separation were achieved below 400ºC. In the case of iron, complete isolation was never attained. However, by decreasing temperature to 150ºC it is possible to obtain aluminium chloride with less iron content. The separation of zinc from the product was also difficult. It was detected that zinc chloride volatilization decreases when other chlorides were present, for example cooper chlorides. In the Cu-Zn alloy, zinc chlorides remained in the condensed product due to interactions with copper. The samples were characterized by scanning- electron microscopy (SEM), X ray diffraction (XRD) and atomic absorption.

Jan 1, 2006

By Zhigang Liang

Effects of the configuration parameters of submerged entry nozzle on the flow field in slab mold were investigated through a water modeling. The experimental results showed, when the original submerged entry nozzle was applied, there was an appreciable level fluctuation in the mold with obviously naked surface and entrapment of mold flux at higher casting speed. By increasing the outlet area of submerged entry nozzle, without any change of other configuration parameters and submergence depth, a proper fluid field with active surface and good covering of mold flux can be obtained, which is proper to meet the requirement for increasing the casting speed and improving the slab quality simultaneously.

Jan 1, 2009

By R. Boom, C. F. Balentina, J. H. L. Voncken

During vitrification of bottom ash generated from the combustion of municipal solid waste (MSW), a Fe-Cu based alloy phase with great value was formed. In order to find proper commercial use in metallurgical industry, it is necessary to separate Cu and Fe. The present study focuses on the sulfide treatment at temperatures of 1400 – 1500oC, in particular with FeS containing minerals. Various sulfide compounds such as Na2S, Al2S3 and Ni3S2 were added to promote the copper removal. Pyrite and zinc sludge (containing ZnS) as waste streams were studied with specific interests. The results showed that both zinc sludge and pyrite are effective for copper removal with the highest removal efficiency of 95% by using pyrite. The copper content drops from 12 wt% to about 2 wt%. However, it is still difficult to remove copper completely from the alloy in one step, and a multi-step operation is needed.

Jan 1, 2008

By C. W. Won

a-etchant solution is the waste material obtained during the etching by ammoniacal solution of printed circuits for PCs. This material contains a substantial amount of copper (13-14%) but is usually discarded after neutralization. In this work, copper recovery from such solutions by electrowinning or cementation using iron scrap was tested. For each method, the effects of temperature, solution pH, initial copper-ion concentration, and reaction time were investigated to obtain optimal conditions for copper recovery.

Jan 1, 1993

By F. Leuzzi

Asbestos is a natural mineral fibre which has been known and utilized commercially for about a century. From the forties, it was employed on an ever-increasing scale throughout the mechanical engineering, building, paper-making and plastics sectors, to name but a few. There are essentially five minerals which provide fibres for industrial applications, namely, the chrysotile variety of serpentine and the amphiboles such as riebeckite, anthophyllite, cummingtonite-grunerite (amosite) and tremolite. About a fifth of the world's asbestos output was once taken by Europe for the manufacture of asbestos-cement products, reinforced plastics, paper and cardboard, panels, soft insulation and spray-on powders. However, in the sixties and seventies the hypothesis regarding the pathogenic nature of asbestos fibres started to gain ground. Moreover, between the sixties and eighties the EU issued a series of regulations designed to bring about a steady decrease in asbestos consumption. This line of action has culminated in recent years in a whole set of directives banning the use of asbestos in all products. This created a major problem, namely, how to clean-up the several million tons of various types of asbestos products in various states of conservation existing in Western Europe. CORDIAM (Pat. RM95 A 000269 and Pat. RM96 A 000782 in the name of ECOTEC S.r.1.) is one of the thermal inertization techniques recently proposed for this purpose. The process provides for the low-temperature ceramization of the toxic-harmful material. Of course, with such a great variety of waste materials and the volumes to be treated, as well as the need to ensure the correct dimensional design of the thermal sections of the treatment plant, it is necessary to know as much as possible about the thermal behaviour of the wastes concerned. This paper details the steps taken firstly to ascertain the thermal behaviour of such materials as may be encountered in day-to-day practice and secondly to examine the influence of the main process parameters on the preliminary design of gas- or fuel-oil-fired rotary kilns of the kind used for waste treatment.

Jan 1, 1999

By Yang Wang, Xiancong Zhao, Hao Bai, Qi Shi, Zhancheng Guo

Linz-Donawitz converter gas (LDG) or basic oxygen steelmaking gas (BOSG) is one of the most important secondary energy sources in iron and steel industry, whose effective use plays a vital role in energy saving and emission reduction. However, the generation of LDG suffers from great fluctuation with respect to the production status of steel making. Therefore, a long term prediction model of LDG generation would be essential in gas system balancing and optimization. In this paper, a long term prediction model for the generation volume of LDG was proposed based on the steelmaking production estimation from Gantt chart and k-means clustering algorithm. Compared with the previous model, this model considered the influence of different steel type on LDG generation. The experimental results of a steel plant demonstrate that the proposed model exhibits high accuracy and can provide an effective guidance for balancing and scheduling of byproduct gases.

Jan 1, 2016

By W. R. Opie

Fundamentals of blast furnace smelting of low grade copper and precious metal scrap and residues are reviewed with emphasis on emission control, by-products produced, slag cleaning for high recovery of metal values and the evolution of an off-gas system to eliminate hydrocarbons that result from decomposition of plastics in the blast furnace- charge. Problems with tin, antimony and nickel in the smelter-refining cycle are discussed.

Jan 1, 1985

By Yuanbo Zhang, Helei Zhang, Heng Yu, Guanghui Li, Zhengwei Yu, Tao Jiang

"Composite agglomeration process (CAP) is an innovative method for preparing blast furnace burden. For CAP, the classified raw materials of pelletizing feeds and matrix feeds are mixed, charged and sintered. The characteristics of these two kinds of feeds obviously affect the permeability of per-ignition bed, as well as the sinter productivity and quality. In this study, the Ergun equation is proposed to predict the pressure drop of CAP bed using the particle size distribution. The calculation process indicates that the Dv and the Em are the two tuning parameters. The results show that there is a gap between the calculated values by Ergun equation and the measured results by pressure drop testing facility. Eliminated this error by modified the Ergun equation and then validated it through experimental studies using simulated CAP mix and test facility. Therefore, the modified Ergun equation can be used to predict the permeability of CAP bed.IntroductionThe sintering process is one of predominant agglomeration processes for preparing ironmaking burden from iron-bearing materials. Sinter accounts for 70-80% of the blast furnace burden in China and the continuous improvement of sinter quality provides a guarantee to anterograde production of blast furnace. Sinter productivity and quality are strongly related to the permeability of the bed during sintering, which is dependent on the structure of the bed before ignition in the early stage [l]. The size distribution, the shape of granules and the bed voidage are the primary affecting factors to pre-ignition permeability."

Jan 1, 2013

By Daniel Chen, Jewel Andrew Gomes, Venkata Palla, Sadia Afrin Jame, David Cocke, Paul Bemazzani

"Textile industries use various kinds of chemicals including dyestuffs and pigments during dyeing and finishing processes. The effluent from these processes includes suspended particles, strong color, high pH and high chemical oxygen demand (COD) that are extremely toxic and make environmental hazard. Although physical, chemical, photochemical, and biological methods are available for treating such wastewater, the electrochemical technique, electrocoagulation (EC), has emerged as an efficient, simple, and cost-effective technology in the last few decades. In this study we present the applicability of EC technique for removing dye, such as direct red dye using iron electrodes, and the optimized conditions such as dye concentration, current density and pH. The degradation of dye molecules was investigated using UV-visible spectroscopy. The EC-floe was also characterized using SEM/EDS, XRD and FTIR.IntroductionWastewaters generated by textile industries contain large amounts of toxic aromatic compounds, especially azo dyes. Azo dyes and their degradation products, such as aromatic amines, are highly carcinogenic. These effluents are also responsible for causing high levels of color. The colored wastewater released into the environment is also a source for disruption of aquatic life and aesthetic pollution as well [1].In most textile industries, dyeing and finishing are the two important processes which are generally applied. These two common processes generate significant amount of wastewater, which may contain, suspended particles, high pH, strong color and high chemical oxygen demand (COD) concentration [2]. Low pH and high temperature are other polluting factors from the waste water. Textile industries make use of about 10,000 dyes and pigments [3]. Disposal of these colored wastewaters poses a major problem for the industries as well as a threat to the environment. In textile industries, because of the low efficiency (60-90%) of dye fixing on textile fibers, substantial amounts of unfixed dyes are released in waste waters. The conventional method for treatment of textile wastewater was a combination of biological, physical and chemical methods [2]."

Jan 1, 2011