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By Zhen Zhang, Jiang Diao, Tao Zhang, Yi Ren, Lu Jiang, Xiao-Man Yan, Bing Xie

The precipitation behavior of phosphorus enrichment phase was investigated by slag modification with Al2O3. The mineral phase of the original slag and modified slags were measured by mineral phase microscope, SEM+EDS and XRD. The mechanism of Al2O3 modification was discussed according to the thermodynamic theory analysis software (Factsage version 6.3). The results show that the high phosphorus solid solution (nˊ2CaO·SiO2-3CaO·P2O5) was generated by the continuous reaction of nC2S-C3P (nˊ＜n) solid solution and Al2O3 under 1350℃. The amount of initially precipitated solid solution (nC2S-C3P) was reduced and even disappeared with the increasing of Al2O3. If the addition of Al2O3 is enough in the slag, the high phosphorus solid solution (nˊC2S-C3P) that generated by the above mentioned reaction will continue to react with Al2O3 to produce Ca2Al2SiO7 and even C3P, which was demonstrated that the addition of Al2O3 has a positive influence on the precipitation of phosphorus enrichment phase.

Jan 1, 2015

By Guangliang Wu, Dong-chang Huang, Xin-bin Liu

High temperature mechanical properties of 50Cr5MoV roll steel was investigated by Gleeble 1500 thermal simulator testing machine The morphology, composition and microstructure of fracture surface were observed and analyzed by OM, SEM and EDS The results are indicative of that, there are two brittle temperature zones of 50Cr5MoV roll steel at the temperature of 600°C~950°C and 1300°C~1450°C, respectively. The section shrinkage rate is less than 60% The fracture mode changes from mixed ones dominated by intergranular to toughness transgranular one with the increase of temperature at the range of 650°C~1300°C. The fracture is along the solid--liquid phase at the range of 1300°C~ melting point It is crucial to formulate the 50Cr5MoV casting technology, to prevent the cracks and improve the quality of 50Cr5MoV roll steel.

Jan 1, 2016

By Youliang He

Twin-roll casting is an integrated casting and rolling process that involves the continuous solidification of a melt and the plastic deformation of the solidified metal between two rotating rolls. Computer modeling is a valuable tool to help engineers understand the metallurgical process during twin-roll casting. However, commercially available software can only model either the fluid flow/heat transfer of the melt or the plastic deformation of the solid, but not both. In this study, an object-oriented finite element program was developed to simulate the steady-state fluid flow, solidification and plastic deformation of an A7,31 magnesium alloy in a horizontal twin-roll caster. The melt, the mush zone and the solid were treated as a generalized Newtonian flow in an Eulerian reference frame and different constitutive equations were employed to describe the material behaviours. The effect of operational parameters on the solidification process was discussed based on the simulation results.

Jan 1, 2010

By C. A. Pickles

Microwave processing is a relatively new technology that has been successfully applied in a number of industries. However, in the field of metal extraction, there is a paucity of success, despite considerable hype in the early years. Increased reaction rates, lowered reaction temperatures and higher energy efficiencies were some of the advantages claimed. Even with over almost two decades of research and some pilot plant studies, microwave metal extraction remains essentially a laboratory technique. In this paper, the research performed over the last few decades will be reviewed and some reasons for the lack of success in developing microwave metal extraction processes will be discussed. Based on the knowledge gained from these experiences, a more informed view of microwave heating can lead to the realization that there is still some untapped potential for this heating technique in metal extraction processes.

By Magnus Ek

After the installation of three new converters as part of the recent expansion of the Rönnskär smelter completed in 2000 work continues to further improve the converter operation. The converter upgrade led to an increase in blister copper taps from 150 tons per batch to more than 300 tons. The total cathode copper production increased from 130,000 tons in 1999 to 230,000 tons in 2001, the first year in full production. In recent years focus has been to improve operating practise, maximize the blowing time, extend the converter campaigns hence to reduce the specific brick consumption and improve the converter slag composition.

Jan 1, 2005

By Lucas L. da Costa, Sergio N. Monteiro, Romulo L. Loiola, Tammy G. Rodrigues Portela

"The fibers extracted from the petiole of the buriti palm tree are relatively strong as compared to other lignocelluloses fibers, with a potential for composite reinforcement. In this work, polyester matrix composites incorporated with these fibers were investigated for their flexural behavior. Specimens with up to 40% in volume of continuous and aligned buriti petiole fibers were bendtested until rupture. The results showed an increase in both the composite mechanical strength and the stiffness with incorporation of these fibers. A fractograph analysis by SEM disclosed a moderate adhesion mechanism between the buriti petiole fiber and the polyester matrix. This mechanism is apparently responsible for the improved performance of the composites.IntroductionIn recent years, the substitution of energy-intensive synthetic materials for natural ones is being considered in many industrial sectors including automobile, packing and textile [1]. A typical case is that of natural fibers, mainly those obtained from cellulose-based plants also known as lignocelluloses fibers. They have being investigated in the past two decades, aiming to replace synthetic fibers, particularly the glass fiber, commonly used as polymer composite reinforcement [2-8]. From the engineering point of view, lignocellulosic fibers present today important environmental, economical, societal and technological advantages already discussed [7-8]. Moreover, several lignocellulosic fibers are known since the beginning of our civilization and still cultivated or naturally extracted all over temperate and tropical regions of the world. According to Kalia et al [1 ], these fibers can be classified by their origin, as shown in Table 1."

Jan 1, 2011

The results of laboratory, large-scale laboratory and commercial scale investigations regarding the process of slag melts cleaning by oxidizing-reduction gas mixtures with a wide range of Po2 and the use of matte of various compositions as an extracting phase are presented. The copper, nickel and cobalt behavior during the cleaning process has been studied based on SEM and x-ray Microprobe of the quenched slag melts. The general cleaning mechanisms have been found. On the basis of the obtained data the most efficient cleaning methods have been proposed.

Jan 1, 2003

By Li Ma, Shaoguo Chen, Gele Qing, Qihang Liu, Keng Wu

Olivine contains higher MgO element, which can be added into blast furnace burden to improve slag stability and fluidity. Effect of calcined olivine and untreated olivine on low silicon pellet production process and quality was studied in this paper. The results shows, calcined olivine has no effect on bursting temperature of green pellet, however the bursting temperature of green pellet will decrease with increase of untreated olivine ratio. Untreated olivine has slight effect on green pellet strength than calcined olivine while the ratio is higher than 2%. The compressive strength of low silicon pellet will increase first and decrease afterwards with increases of calcined olivine ratio under firing temperature of 1250°C, whereas, the changing sequence is reverse fired under 1280°C. The result of untreated olivine pellet compressive strength is same as calcined olivine pellet. However, the compressive strength and metallurgical property of calcined olivine pellet is slightly higher than that of untreated olivine pellet under same condition.

Jan 1, 2015

By Eric Pirard

Theoretical studies carried out on shape analysis supply mathematical tools to analyze the influence of grain shapes on ore beneficiation. In the case of statistic images like those encountered in applied mineralogy parametrical and harmonical analysis methods are used. It is important that the shape parameters are adapted to the specific processes involved in ore beneficiation, while remaining easy to manipulate. The inertia parameters are considered in the scope of granulometric and gravimetric processes It appears that they are able to distinguish between the resulting products where very popular shape parameters are not. The measured statistics are analyzed through discriminant analysis procedures in order to estimate the importance of morphological differentiation and the aptitude of shape parameters to account for this.

Jan 1, 1989

By Theodore Ineich

The “BIOMOre” project aims to prove the technical feasibility of indirect in situ bioleaching of sulfide minerals contained in a deep underground deposit, by bringing together the disciplines required to make a success. The underground location in Poland was provided by project partner KGHM inside an operating copper mine. Key components of this project were the design and construction of a pilot plant, and its operation in an underground environment. This project also included a ∼250 t (100 m3) fragmented rock reactor hydraulically connected to the pilot plant. The pilot plant consisted of several tanks and pumps, a fluidised bed ferric iron generating bioreactor containing immobilised acidophilic iron oxidation biomass, and all the required instrumentation and utilities. Before the bioleaching phase could start, the rock reactor had to be flushed continuously firstly with water to remove chloride salts that are corrosive and also harmful for the bacteria used in the bioreactor, and secondly, with sulfuric acid solution to react with the carbonates present in the ore matrix. This paper summarizes the design, construction, commissioning, and operation of the pilot plant.

By Guiming Yang, Xiaoxian Huang, Zhiyun Ji, Min Gan, Lishun Yuan, Xiaohui Fan, Zhiyuan Yu

"The roasting characteristics of hematite pellets containing MgO were studied where magnesia powder, serpentine and magnesite were used as magnesium-additives respectively. The mechanical strength of both preheated and roasted pellets decreased when MgO content increased, which implied the addition of MgO had an adverse effect on pellet consolidation. By adding flux containing CaO, the mechanical strength of both preheated and roasted pellets were improved. The addition of calcium flux facilitated the formation of calcium ferrite and provided a certain amount of liquid phase, resulting in faster diffusion ofMg2+ and Fe3+. The result showed that diffusing speed of Mg2+ was enhanced by 1.48 times, and rate constant of Fe203 crystalline growth was enhanced by 62% when basicity was around 0.4. Improvement of mineralization degree and recrystallization of Fe203 assisted in consolidation of hematite pellets containing MgO.IntroductionOxidized pellets are ideal iron-bearing burdens in blast furnace. At present, magnetite is the main raw material for oxidized pellet production in China. However, as the rapid development of iron and steel industry, resources of magnetite have been depleted and cannot satisfy the requirement of pellet production. Using hematite concentrates to produce oxidized pellets has become a trend [1, 2]. Many pellet enterprises abroad nowadays have adopted high proportions of hematite concentrates when producing oxidized pellets, e.g. the percentage is 100% in a lot of Brazilian factories [3, 4]. But high proportion of hematite concentrates will lead to low mechanical strength and high reduction swelling index of pellets. Some studies show that Mg-bearing pellets have excellent metallurgical properties, and the reduction swelling phenomenon can be solved by adding fluxes containing MgO [5, 7]. However, there are problems such as low pellet strength and bad roasting characteristics for MgO-bearing pellets, which remains an obstacle in pellet industry. Hence, it's vital to undertake the study on strengthening measures for indurations of Mg-bearing hematite pellets."

Jan 1, 2013

By James R. Craig

The General Image Processing System (GIPSY) is being employed for the quantitative textural analysis of complex sulfide ores from the Southern and Central Appalachians and for the determination of liberation characteristics of the mineral constituents during grinding. Optical images from a microscope-mounted TV camera or from 35mm film are converted into digital images which are subsequently analyzed by GIPSY, a transportable image processing software package. Properties measured by GIPSY include spatial distribution of mineral constituents, grain sizes, grain shapes, grain orientation and mineral co-occurrences.

Jan 1, 1982

By Patrick R. Taylor

In the search for the development of more "environmentally friendly" and more intensive waste disposal approaches to meet more and more stringent environmental regulations, thermal plasma-based processes are considered one of the most promising alternatives to well- established technologies such as incineration. This paper presents an overview on the research and development status of thermal plasma-based waste remediation technologies. The properties of thermal plasma are described. Due to its unique feature of high-energy intensity and super high temperature, thermal plasma is particularly capable of destroying organic- containing wastes. Its potential and promising application to waste remediation may include: treatment of incinerator ashes; metallurgical dusts (especially, electric arc furnace dust); medical wastes; radioactive wastes; and other Resource Conservation and Recovery Act (RCRA) listed hazardous wastes. Many research institutes and vendors have been involved in the development of thermal plasma-based waste treatment technology encouraged by the cleanup programs supported by the Environmental Protection Agency (EPA), the Department of Energy (DoE) and the Department of Defense (DoD). More recently, thermal plasma-based waste treatment technologies (sometimes called plasma-enhanced pyrolysis) are focused more and more on not only just destroying organic wastes but also on how to practically, and economically recover energy contained in the organic waste materials in addition to the recovery of metals in order to offset the high operating costs.

Jan 1, 2003

By Patrick R. Taylor

In the search for the development of more "environmentally friendly" and more intensive waste disposal approaches to meet more and more stringent environmental regulations, thermal plasma-based processes? are considered one of the most promising alternatives to well-established technologies such as incineration. This paper presents an overview on the research and development status of thermal plasma-based waste remediation technologies. The properties of thermal plasma are described. Due to its unique feature of high-energy intensity and super high temperature, thermal plasma is particularly capable of destroying organic-containing wastes. Its potential and promising application to waste remediation may include: treatment of incinerator ashes; metallurgical dusts (especially, electric arc furnace dust); medical wastes; radioactive wastes; and other Resource Conservation and Recovery Act (RCRA) listed hazardous wastes. Many research institutes and vendors have been involved in the development of thermal plasma-based waste treatment-technology encouraged by the cleanup programs supported by the Environmental Protection Agency (EPA), the Department of Energy (DoE) and the Department of Defense (000). More recently, thermal plasma-based waste treatment technologies (sometimes called plasma-enhanced pyrolysis) are focused more and more on not only just destroying organic wastes but also on how to practically, and economically recover energy contained in the organic waste materials in addition to the recovery of metals in order to offset the high operating costs.

Jan 1, 2003

By Joël P. T. Kapusta, Romeo U. Pagador, Noparut Wachgama, Chumnoom Khuankla

"Thai Copper Industries (TCI) is a custom copper smelter and refinery in Rayong, Thailand, with an annual capacity of 165,000 tons of cathodes. It employs the El Teniente Technology as the primary smelting reactor to produce white metal from copper concentrates. The white metal is further treated in Hoboken Siphon Converters to produce blister copper then refined in anode furnaces before being cast into anodes for electro-refining in the on-site tankhouse.Thai Copper Industries is the first copper smelter to install and successfully operate on a commercial scale with the Air Liquide Shrouded Injection (ALSI™) Technology in the Hokoben converters with sonic injection of oxygen enriched air and nitrogen for cooling of the injector tip areas. Following commissioning and the establishment of operating practices, the performance of the Hoboken converters with ALSI™ Technology produced outstanding results. The unique combination of an El Teniente and Hoboken siphon converters, both of which are bath smelting operations, offers very high blowing and oxygen efficiencies. As a consequence, reverts recycling was accelerated with minimal build up on the mouth, end-plates or even below the siphon that is typical in Hoboken converters.These outstanding results in the Hoboken Siphon Converters with ALSI™ Technology helped the TCI Plant reach a production of about 75% of its capacity within four months despite the fact that the TCI staff is quite young and its converter know-how and experience are not yet fully developed."

Jan 1, 2009

By Susan Fredholm, Randolph Kirchain, Jeremy Gregory

"Jurisdictions across the world have struggled to create and finance systems that can effectively collect and process electronics waste (e-waste). Many different system architectures have been proposed and implemented, but it is difficult for policy-makers and system architects to compare the costs and benefits of different systems, particularly when the systems operate in different contexts. This paper presents a systematic methodology that seeks to address this challenge and uses data from several existing electronics recycling systems across the world to illustrate its implementation. The methodology characterizes three main system characteristics: architecture (e.g., financing and collection methods), context (e.g., jurisdiction population, density, and wages), and performance, both economic and materials collection. A comparison of systems in Europe and North America with different system architectures and contexts illuminates the importance of using the methodology to discern the extent to which architecture and context drive system performance.IntroductionElectronic waste (e-waste) recycling offers several environmental benefits when processing is done responsibly. The controversy around e-waste recycling systems rarely debates such benefits; rather, it focuses on the characteristics of an effective system and whether benefits outweigh costs. Historically, the costs of recycling most electronics have outweighed the value of the scrap recovered. Thus, in the absence of legislation, e-waste recycling systems have been limited to private recycling of high-value waste with minimal consumer participation. E-waste recycling systems now exist in many locations worldwide including Asia, the European Union, Canada and the United States and the amount of related legislation continues to increase. Numerous approaches have been proposed including landfill bans, extended producer responsibility (EPR) and consumer advance recovery fee (ARF) funded recycling systems."

Jan 1, 2008

By Zhonglin Ye, Yifeng Shi

"This paper has outlined forms of Au & Ag losses in copper smelting process and methods for increasing Au & Ag recovery, analyzed factors influencing Au & Ag recovery in copper converting process, presented Au & Ag behavior in copper electrorefining process, and reviewed effect of current density/electrolyte circulation rate during electrolysis and surface finish of cathode on Au & Ag losses. Measures and research direction for decreasing Au & Ag losses in electrolysis have also been introduced. Based on Au & Ag behavior in copper electrorefining process and previous studies by others, new approach for increasing Au & Ag recovery in copper smelter has been discussed. And brief comparison has made between continued multiplication method and equilibrium method application in the case of calculation of Au & Ag recovery in copper smelter.IntroductionAs gold and silver are the major by-products from copper smelting process, efficient Au & Ag recovery has become one of the key approaches for copper producers to increase economic efficiency. With similar physicochemical properties, Cu, Au and Ag belong to the first subgroup of elements in the same periodic table. Au and Ag will be enriched into Cu phase firstly when both matte-slag phase and copper-matte phase appear in copper smelting process. However, great changes have taken place in Au & Ag proportions into individual phase due to changes of physicochemical conditions in each smelting process. Metallurgists at home and abroad have carried out a great deal of pilot plant tests and laboratory tests in order to increase Au & Ag the former Soviet Union with regard to Au & Ag losses in copper smelting process in the 1970s and 1980s, and he proposed solutions to increase Au & Ag recovery in copper metallurgical plants. As more than 20 years passed, Jingchun Lu's paper, Discussion on Increasing Au & Ag Recovery in Copper Smelting System, remains as a literature of the most comprehensive study. Based on Jingchun Lu's literature, the authors of this paper discussed new approaches to increase Au & Ag recovery in copper metallurgical plants with combination of many researches done by other researchers for over 20 years."

Jan 1, 2013

By S. Neogy, M. Gupta, D. Srivastava, V. Kain, S. Roychowdhury, R. C. Prasad, G. K. Dey

"Austenitic stainless steels are an important material of construction for Boiling Water Reactors (BWR). These stainless steels are amenable to strengthening by strain hardening. Various deformation modes at different test temperatures and strain become active. In the present investigation type 304LN stainless steel was used in the annealed and strain hardened condition. Thin foils were prepared from gauge section for transmission electron microscope (TEM) investigation after tensile testing at room temperature and at 288°C. TEM investigation reveals that twinning is the major mode of deformation for the tests done at room temperature while dislocation cross-slip is the major mode of deformation at higher temperature. Stacking faults were also observed to a limited extent. The extent of twinning was much higher for the tests done using the rolled material. The formation of martensite in the stainless steel due to straining was investigated by the analysis of selected area diffraction patterns.IntroductionAustenitic stainless steels (type 300 series) are an important material of construction in Boiling Water Reactors (BWR). These stainless steels cannot be heat treated but can be strengthened by cold working [1]. Nitrogen alloying of these stainless steels result in high strain hardening rates and higher strength without any loss in toughness [1]. Stress Corrosion Cracking (SCC) in BWR of these types of stainless steels have been attributed to surface strain hardening and strain hardening ofregions adjacent to constrained weldment [2].The test temperature [3, 4], prestrain [5] and nitrogen level [5] has been reported to affect the deformation mechanism during tensile testing. Byun et al. [3] have reported the formation of martensite, dislocations, stacking faults and twinning during tensile deformation, the extent of each depending on the test temperature. Strain localisation has been reported to occur during tensile deformation in irradiated stainless steels [ 6]. The behaviour of rolled material during tensile testing is similar to that of irradiated material to a large extent [3]. Austenitic stainless steels are low stacking fault energy (SFE) materials in which various types of microstructures have been reported to form during tensile deformation and the strain is also highly heterogeneous in nature in these stainless steels which aides SCC in BWR environment to a large extent [7]. During cold working of austenitic stainless steels second order twinning has also been reported [8]. Knowledge about the deformation mechanisms operative in the strain hardened austenitic stainless steels during tensile testing at different temperatures is essential to understand the material deformation behavior and the present study aims at enhancing the existing understanding."

Jan 1, 2011

By J. W. Evans

Mathematical modeling has now become a standard technique in the development of new technology and the improvement of existing technology in the processing industries. Physical modeling has a longer history but a smaller following at present. The paper reviews some examples of the application of both types of modeling in non-ferrous metal extraction, particularly within the copper and aluminum industries. The objective is to show that well founded models can lead to results that have practical consequence in scaleup, design and operation.

Jan 1, 1993

By Jim Sundal

Primary steel manufacturers using electric arc furnaces generate one of the largest hazardous waste streams nationwide. The waste stream, known as electric arc furnace dust, is a listed hazardous waste with the designation K061. Oregon Steel Mills, Inc., (OSM) of Portland, Oregon, has implemented a process known as Glassificationn, which uses KO61 as an ingredient in an onsite recycling process. Because OSM was able to demonstrate that the Glassificationm recycling process beneficially uses all toxic constituents in the electric arc furnace dust and that the recycling process produces marketable products, the process is not subject to Resource Conservation and Recovery Act (RCRA) permit requirements. The marketable products manufactured using Glassificationn include roofing granules, ceramic glazes and colorants, abrasive blasting media and, more recently, synthetic slag fluidizers. The purpose of this paper is to identify the regulatory issues for recycling hazardous waste and demonstrate that OSM glass frit is effective as a slag fluidizer in primary steel manufacturing.

Jan 1, 1994