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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 Adam Gesing, Paul Marchwica, Jerry Sokolowski, Sharon Lackie

"Often referred to as SEM-EDX, energy-dispersive spectroscopic analysis of characteristic fluorescence x-ray is a standard technique for semi-quantitative elemental composition analysis in scanning electron microscopy. It is quick and extremely useful for identification of phases in the sample microstructure, as long as the constituents are significantly larger than the probe volume from which the fluorescence x-rays originate. The probe volume ranges from a few to several microns, depending on the electron beam spot size and the acceleration voltage. We report on a new variant of an EDX technique developed to overcome this limitation and allow quantitative elemental analysis of smaller phase constituents, down to a size of several nanometers. This variant involves the calculation of compositions of individual phases from multiple analyses of areas containing phases of interest. This significantly increases the usefulness of EDX for quantitative analysis of new nano-structured materials.IntroductionIn any elemental micro-analytical method, the sample material is illuminated by a probe beam that excites an interaction volume of a sample to emit a characteristic signal. This signal in turn interacts with the sample material through absorption and fluorescence mechanisms before a portion of it is collected by a suitable detector and analyzed for elemental composition. The spatial resolution of the method depends on the minimum interaction volume between the probe beam and the sample material.Laser light beams can be tightly focused to a spot size limited by the photon wavelength and can be used to sample the surface of any material. In micro-LIBS (laser-induced plasma spectroscopy) a focused laser beam ablates and vaporizes a small volume of material from the sample surface, creating a plasma spark. Spectral analysis of the light emission from the plasma spark allows the semi-quantitative determination of the elemental composition of the material removed from the sample surface. The smallest reproducible craters achieved are ~ 3mm in diameter and a few nanometers in depth. [l]Particle probe beams of ions or electrons can be focused to a diameter of a few nanometers at the point of impact on the sample. Ions sputter the sample atoms from the point of impact, and the sputtered ionized material is analyzed by mass spectroscopy in a secondary ion mass spectrometer (SIMS). [2] This gives SIMS resolution in a nanometer range. SIMS equipment, however, is expensive and not readily available."

Jan 1, 2013

By Juha Järvi

Outokumpu Zinc Oy has two separate roasting lines with fluidized bed furnaces and waste heat boilers for calcine collection and heat recovery. During the last 30 years, zinc production in Kokkola plant has increased continuously and at the same time the raw materials have changed. Therefore, the waste heat boiler has been under continuous research and development. The waste heat boiler plays a significant role in the process and consequently the reliability and efficiency of the device is important for the effectiveness of the entire process. Many changes have been made to the boiler in the last decades. New radiation tube screens, tube bundles, and baffle-plate constructions have been added to the boiler and also rapping systems for the dust have been developed. The latest improvement to the boilers was a baffle wall, located in the middle of the radiation section roof in the first boiler, and baffle plates in the lower part of the convection section in the second boiler. The new boiler design and optimization were carried out using physical water and air-dust modeling as well as computational fluid dynamics. The modeling work agrees well with experiences in practice. The latest developments have increased the operating hours per year and the effectiveness of the waste heat boiler.

Jan 1, 2002

By Andreas Nolte

In 1999 HÜTTENWERKE KAYSER AG (HK) in Germany will produce more than 180,000 t/y of electrolytic refined copper. To achieve this production from materials with copper grades from two to seventy percent and diverse copper alloys, HK operates three blast furnaces, one holding furnace two Peirce Smith converters and two anode furnaces. Technical, metallurgical and economic factors for the ongoing process optimization are outlined. The fluctuating quality and quantity of raw materials renders complex this optimization. The principal variables are the quality and quantity of process consumables: coke, copper-iron, limestone, oxygen, as well as the blending of feedstock and a new organization of the operating crews. The search for new metallurgical process parameters is ongoing. HK started with an intensive research programm in November 1997. As a result it will be possible to cut processing costs by about ten per cent, to increase the blast furnace capacity by ten per cent and to lower the metallurgical losses of copper and tin in the slag by more than ten percent. The presentation concludes with information on future steps to continue the optimization process.

Jan 1, 1999

By C. K. Gupta

The paper reports on the experimental work and results obtained in processing a xenotime concentrate. The rare earth resource concentrate has been treated by three different methods namely, hydrothermal leaching, alkali roasting and alkali pugging or baking. The recovery in hydrothermal leaching with caustic soda at 150-160°C has been 89%. En comparison, processes involving alkali roastings with soda ash at 850°C and with caustic soda at 500°C, and alkali pugging or baking with caustic soda at 200°C have given recovery values close to 100%

Jan 1, 1992

By Morimasa Ichida

One of the key factors of stabilized blast furnace operation under the conditions of high productivity and high pulverized coal rate is to enlarge the raceway to reduce the dead man area. With a reduced dead man area, the descent area is enlarged and the central gas flow is maintained at the same time. In this study, raceway furnace experiments were conducted with tuyere velocity and coke strength changed both in hot and cold conditions to measure the coke degradation rate. Using the coke degradation rate measurements, we examined the equivalent relation between the coke strength and tuyere velocity for coke degradation in the raceway. In addition, in this paper, we discuss the increase in tuyere velocity in relation to an increase in coke strength.

Jan 1, 2006

"Silver is traditionally recovered in base metal smelters (lead and copper), or as a by-product of other precious metals (gold and/or PGM's). This paper presents the results of non-conventional techniques to recover silver from complex materials. The PLATSOL® process has been developed to recover, in one step and without the use of cyanide, base metals (copper, cobalt, nickel) and precious metals (gold, PGM's) from sulphide concentrates too low in grade to enter the mainstream extraction processes. Silver is only partially recovered in solution with gold and the PGM's during the PLATSOL® process. However, the silver minerals are transformed into silver chloride, which can then be recovered from the PLATSOL® residue using conventional techniques. Some South American silver concentrates contain levels of impurity (mostly arsenic) so elevated that the penalties incurred significantly affect the process economics. The present results have shown that a low temperature calcination process transforms the concentrate into a product well suited for traditional recovery treatments. Metallurgical details will be provided, as well as the results of mineralogical studies that helped clarify the process mechanisms.IntroductionSilver occurrences in nature are very diversified, and, therefore, primary silver is produced as a by-product of many base metal and precious metal operations [1], as well as a co-product of most gold ores. However, difficulties can arise when high temperature processes are used for refractory gold ores or copper concentrates, or when the silver concentrate contains impurity elements such as arsenic that trigger high penalties."

Jan 1, 2012

By Leandro Voisin

A new pyrometallurgical treatment alternative is proposed for cleaning complex copper matte with high content of impurities in the copper smelting process, thus, in a suitable furnace, a given amount of pig iron will be added to the liquid complex matte with a matte grade between 65 and 75 % Cu under reducing condition and will produce three liquid phases of matte, copper-rich alloy and iron-rich alloy. Hence, in this study, firstly, a mass balance calculation was made on the basis of the reported data for the distribution ratios of the components among the three phases to define the optimum condition where most of the arsenic can be fixed in the less valuable liquid iron-rich alloy. By taking advantage of the high concentration of arsenic in the iron-rich alloy, the small volume alloy may be disposed in a yard, while the precious elements may be recovered effectively in the liquid copper-rich alloy and/or in the liquid matte. Secondly, laboratory-scale experiments were conducted to apply the proposed process to the matte produced from the slag-cleaning electrical furnace and the Teniente Converter of the Codelco-Norte smelter. The obtained results indicate that the proposed process for cleaning complex matte is promising.

Jan 1, 2006

By Kyong-Hwan Lee

This paper is focused on describing the pilot and demonstration plants for pyrolysis process of mixed plastic wastes developed at Korea Institute of Energy Research (KIER). These plants were constructed at KIER (300 ton/yr) and also Korea R & D Company (3,000 ton/yr) in Kimjae city, in Korea. The raw material used was mixed plastic wastes that were generated from household and industry, etc. The liquid products obtained by pyrolysis at around 400°C were used as an alternative fuel oil. These processes were controlled by automatic control system with continuous operation in a control room. Main process units consist of automatic feeding, melting, thermal cracking systems and vacuum distillation. Their characteristics were automatic pyrolysis operation under vacuum atmospheric pressure, continuous control in feeding of raw material and discharging of solid residue, the recirculation of cracked reactant with a high temperature into the melting reactor and continuous pyrolysis of reactant in circulation thermal cracking system such as constant stirred tank reactor (CSTR), plug flow reactor and light/heavy oil separator, in order to maximize the efficiency of light oil products like kerosene and diesel. In addition, the process performance of pilot plant was described.

Jan 1, 2006

By F. Sakurai

The enlarged Mitsubishi process in Naoshima has been in steady operation since. May 1991. However, the sulfuric acid plants have been in operation for more than 30 years. The acid plants were modernized between 1999 and 2001 by renewing some of main equipment such as the drying tower and gas heat exchangers, and introducing new technology. At the same time, as an electric energy saving measure, the electric power consumption in the sulfuric acid plant was vastly improved by decreasing the volume of gas treated the installation of low temperature activity catalyst in the 1st pass of the converter and optimization of main gas blower runner. Furthermore, last year, the oxygen plant was replaced and enlarged, and anode production increased from 240,000 to 280,000 tonnes per year with an associated increase of sulfuric acid from 550,000 to 660,000 tonnes per year. This paper describes these recent improvements in the acid plant at Naoshima smelter.

Jan 1, 2002

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 K. Th. Mavrommatis

Cleanness of steel is justified, measured and estimated in steelmaking process through different concepts which are mainly based on operational, empirical or semiempirical parameters and describe ?cleanness as a state?. In this work a theoretical concept is developed, considering ?cleanness as a process? and introducing a dynamic aspect into the quantification of cleanness of a steel melt, linking operational parameters with physicochemical variables, which are based on first principles. This concept and the here derived and developed variables and parameters are based on the earlier defined agglomeration index (AI) of a steel melt, the ratio of the mean inclusions diameter (MID) to the mean inter-particle distance (MIPD), which is shown to be a measure of the agglomeration tendency of the melt after deoxidation, and can serve both, to monitoring cleanness during steelmaking operation and to be useful as a basis for mathematical modelling of cleanness and of the metallurgical measures in plant, associated with production of clean steels.

Jan 1, 2006

By F. Leclerc, V. Rebeyrolle, M. Revil-Baudard, A. Jardy, M. Založnik, H. Combeau

"Since the quality of Vacuum Arc Remelted ingots is linked to their chemical homogeneity and metallurgical structure, a modeling study of the solidification during VAR has been undertaken. It is based on the solution of the coupled transient heat, momentum and solute transport equations during the remelting of a cylindrical ingot. Solidification mechanisms implemented in the model include a full coupling between energy and solute transport in the mushy zone, and accounting for nucleation and finite diffusion of solutes at the microscopic scale, in both solid and liquid phases. This modeling can be applied to actual multi-component alloys. In this paper, the macrosegregation in Zircaloy 4 ingots is investigated. To validate the model, one single melt of a homogeneous electrode has been specifically performed. The comparison between the predicted macrosegregation and the experimental results shows the importance of accounting for solutal convection to forecast properly the macrosegregation in remelted ingots.IntroductionVacuum Arc Remelting of zirconium alloy ingots is a key step in the manufacturing process of fuel assembly components in nuclear reactors. The control of the chemical homogeneity is indeed fundamental to ensure the quality and the in-reactor performance of the final products. Despite the use of electromagnetic stirring to homogenize the liquid melt composition, chemical heterogeneities develop in the mushy zone during the solidification stage. One of the main challenges for zirconium producers, as well as titanium producers, is to master the VAR process in order to control the macrosegregation in remelted ingots. Macrosegregation results from the association of microsegregation and transport phenomena. The latter are primarily due to the flow in the liquid and mushy parts. It is now well established [1-4] that the hydrodynamics of the melt pool in a VAR ingot depends on the combined action of the followings: thermal and solutal buoyancy, self-induced electromagnetic force and the periodic centrifugal force caused by the angular movement generated by the stirring. However, for zirconium alloy ingots, the effects of thermal and solutal buoyancy forces on macrosegregation through their influence on the flow in the mushy zone have not been clearly identified."

Jan 1, 2012

By Marilda Macagnan, Rosana de Cassia de Souza Schneider, Valeriano Corbellini, Tiago Bjerk, Mariela de Souza Vieira

The great potential of Brazil for the agricultural production makes our country a generator of agro industrial residues. In this context, the solid-state fermentation appears as a technology that shows alternative ways for those residues, adding values to these raw materials, through the production of substances of industrial interest, besides reducing the possible environmental problems. The main objective of this study was to apply the bovine fat residue associated to the garden grass for the fungal lipase production. Initially, 75 microbial cultures were isolated from garden grass samples after incubation of the mixture with bovine fat. From these cultures were selected the filamentous fungi, whose lipase production abilities were evaluated. The isolation and the selection were accomplished by using a differential culture medium containing Tween 80 as inducer substrate of lipase production. The colonies with lipolytic potential were detected by the presence of white precipitation haloes on the agar. With agro industrial residues the best lipase producer fungus was identified as Penicillium sp in 6 days of solid state fermentation. The crude enzyme obtained was tested in transesterification process for the biodiesel production.

Jan 1, 2008

By P. H. Scaife

The pyrometallurgy industry faces a series of environmental challenges, based on local, national and global issues. While local impacts continue to be important, national and global concerns with Sustainable Development, Greenhouse emissions, Acid Rain and water resources are key strategic drivers for the industry. The environmental problems of the industry are well known: emissions of sulphur dioxides and carbon dioxide, disposal of arsenic wastes, consumption of fresh water, fate and impact of minor components/trace elements in raw materials (whether conventional or complex, or wastes). Solutions to these problems require the application of Cleaner Production principles (waste minimisation, energy conservation, product design to enable ease of post consumer recycling), new technology and scientific studies to assess impacts of discharges. A number of opportunities, driven by environmental concerns, have also been identified

Jan 1, 1994

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 Jiu-ju Cai, Wen-chao Liu, Fei Liu

"The material flow of urban eco-industrial system includes linear flow, recycling flow, branching flow, converging flow, etc., which consequently lead to the system complexity. Comparing the urban eco-industrial system to ecosystem, it can be concluded that this complexity is caused by the system adaptability. In the system, the interaction and adaptability between the agents themselves and between the agents and the environment stimulates the changes of material-flow mode, which lead to the evolvement from traditional industry to the eco-industry. Focusing on the evaluation of this evolvement process, two material-flow models are established in this paper, one of which is for the system itself and the other for the agents in system. The latter model is applied to analyze the interrelationships among mass, energy and pollutant flow in the iron and steel industry, and to make the direction clear to improve the resource and energy efficiency and decrease the environmental load.1 IntroductionIndustrial system is a subsystem of urban system, and they are interconnected and interrelated through material flow. The industrial development causes the urbanization. But the traditional industrial mode, characterized by high consumption, high pollution and low efficiency, also causes the “urban problems”, and leads to the reduction of resources carrying capacity and the increase of environmental load. Nowadays a lot of researches focus on how to realize the sustainable development of industries and cities. Thus comes the urban eco-industrial system guided by industrial ecology.Regarded as a Complex Adaptive System (CAS), the urban eco-industrial system evolves for quite a long time. According to Holland’s description on CAS, CAS consists of adaptive agents, which interact with the environment and other agents, learn and accumulate experiences, and accordingly change their own structures and motion modes. In this way, the evolution of the whole macro system is improved [1]. The evolution from traditional industrial system to urban eco-industrial system is mainly reflected in the variety of internal material flows which include not only linear flows but also recycling flows. Therefore, to construct models which clearly analyze industrial metabolism, is of great importance to evaluate industrial system evolution.The article is organized as follows: Section 2 describes the urban eco-industrial system. Section 3 presents the system-oriented metabolic analysis model and the agent-oriented one, analyze the interrelations of energy flow, material flow and pollutant flow in Chinese iron and steel industry through the latter model, and indicates the directions of improving the resource efficiency and energy efficiency, and decreasing the environmental load. Section 4 concludes."

Jan 1, 2008

By Claire A. Chanenchuk

Catalytic Extraction Processing (CEP), a technology commercialized by Molten Metal Technology, Inc., a US.-based company, can convert industrial, household, and government wastes into commercial resources. CEP is an innovative elemental recycling technology that uses a molten metal bath to completely dissociate hazardous or toxic components of a feed and convert them to valuable products. The catalytic action of the molten metal bath converts the feed to its elemental constituents and the reducing atmosphere prevents the formation of any dangerous byproducts (NOx, SOx, dioxins, furans, etc.). Selective reactant addition allows engineering of valuable products from otherwise unexploited resources. Synthesis gas is generated from hydrocarbon feeds, ferro-alloys from metallic wastes, and ceramics from select inorganic species. Commercial-scale processing of multiple wastes and waste surrogates has been carried out at a destruction and removal efficiency exceeding 99.9999 wt.%, validating theoretical predictions. Unlike conventional hazardous waste treatment technologies, CEP offers resource recovery, minimal byproduct generation, and the potential for closed-loop recycling.

Jan 1, 1994

By Jason Eric Sallee

Ongoing operations at the Cyprus Miami Smelter involve the use of an electric furnace for settling of copper matte from discard slag. Proper operation of the electric settling furnace is a major factor in minimizing losses of copper to the discard slag. Recent test work at the smelter has shown improvement in the operation of the electric furnace with a subsequent improvement with regard to the copper losses. This paper presents a general discussion of the Cyprus Miami Smelter operation, past results with respect to copper losses, recent operational changes and test work, and the subsequent results.

Jan 1, 1999

By M. Boussuge, M. -D. Dupuits, A. Piant

This paper summarises a part of the work that has been essentially carried out at the Ecole des Mines de Paris in the framework of an Eureka European programme funded by the French Ministry of Industry, in partnership with Metaleurop and Carborundum (subsidiary of Saint Gobain). It deals with the measurement of different properties (density, thermal linear expansion, elastic modulus, strength) of a SiC-based refractory constituting the trays that are used in the refining columns in the New Jersey zinc distillation process, especially in the boiling section. These parameters have been investigated to check the homogeneity of the asreceived trays as well as to estimate the influence of ageing of the material under operating conditions. With this aim, specimens have been sampled in used trays having more than two years of operation. The as-received trays exhibited a good homogeneity, the strength being slightly lower in the direction in which they are compacted. Despite microstructural changes, most of the properties measured at room temperature are not significantly affected by ageing. High temperature tests involved thermal treated under vacuum to remove metallic zinc before testing at high temperature. An increase in temperature, as well as ageing, induces a decrease in the elastic modulus and strength.

Jan 1, 2000