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By Peng ZANG, Qihang Liu

Experimental work was conducted to determine the relationships of coal char conversion with temperature and heat absorption. The results show that at an earlier stage of the coke forming process, lump coal would absorb large amounts of heat but the increase of high temperature strength of lump coal was not significant. Contrarily, the lump coal’s high temperature strength was greatly improved at later stage of coke forming process. A number of residual coal was found in most tuyere coke samples illustrating that the lump coals added in the melter gasifier were not completely transformed into coke when they arrived at the tuyere region. The results indicate that the improvement of lump coal’s high temperature performance is limited in the melting gasifier by the low coke forming rate which could become the core factor of fines generation of lump coal in the melting gasifier.

Jan 1, 2016

By Selvin Yesilay, Guray Kaya, Bekir Karasu, Asli Cakir

"In this investigation, the wastes of Eti Maden Kirka Boron Company of Turkiye were evaluated in the production of diopside and anorthite-based glass-ceramic glazes suitable for porcelain tiles fast and single-fired under industrial conditions. First of all, high wear resistant frits were produced with the use of concentrator and derivative borax wastes. Second of all, pre-engobed porcelain tile bodies were coated with the standard and newly produced frit-based glazes and industrial fast single-firing was employed. Final products were undergone to the certain standard tests to determine their Vickers hardness, wear resistance, thermal expansion coefficient values, gloss and coloring parameters. The micro-structures and phase formations of the fired glazes were also studied. Consequently, it was confirmed that the utilization of borax solid wastes in fast single-fired porcelain tile glass-ceramic glazes is possible. Introduction Porcelain tiles were introduced at the end of 1980s by Friandre, one of the leading Italian porcelain manufacturers. The American National Standard Specifications for Ceramic Tile defines porcelain tiles as: dense, smooth, impervious (with water absorption value less than 0.5 %) and stain resistant [1]. The excellent technical performances for ceramic tiles, such as mechanical, wear, frost and chemical resistance that make their use possible in indoor and outdoor building applications [2-3]. In the last decade, the growth rate of the global production of porcelain tiles increased more than those of other ceramic products; in fact, the technical properties of porcelain tile, coupled with even more improved aesthetic appearance, gave it a prominent role on the tile market [2]. Glass-ceramics are composed materials of one or more crystalline phases immersed in a residual glassy phase [4-5]. Glass-ceramic technology is based on controlled nucleation and crystallization of bulk glass [6]. The concepts of controlled crystallization of glass designate the separation of a crystalline phase from the parent glass in the form of tiny crystals. Their growth rate and final size are controlled by a suitable heat treatment [7]."

Jan 1, 2008

By Donato Firrao, Giorgio Scavino, Paolo Matteis

"The fatigue behavior of two high-strength sheet steels used to produce car bodies, a dual-phase steel and a TWIP one, both with ultimate tensile strength close to 1 GPa, is investigated.Unnotched tensile specimens are fatigue tested at room temperature with constant load amplitude and zero load ratio, in order to determine their 1 million cycles fatigue limit, both in the asfabricated sheet condition and after the resistance spot welding of one small homologous sheet square onto the calibrated length of the tensile specimen. Moreover, pre-cracked compact tension specimens are tested with load ratio 0.1 to determine the Paris fatigue crack growth curve.The fatigue results are completed with crystallographic, microstructural, tensile, and fractographic examinations, and the influence of the microstructure and of the welding processes is discussed.IntroductionCar bodies are increasingly made with high-strength weldable steels, in order to reduce vehicles' weight (to save fuel and reduce air pollution) and to improve the vehicle occupant safety in case of car crash. The main mechanical requirements of these steels in service are fracture strength and energy absorption, relevant for crashes, as well as fatigue endurance, relevant for ordinary car usage. [1]Steel sheets for car-body applications are usually made by continuous casting, hot rolling, cold rolling, continuous annealing (or other continuous heat treatment), and protective coating (in some cases). The sheets are then cold formed (deep drawn) to produce car body parts. Finally, the car bodies are built by assembling several deep-drawn parts, often consisting of different steels, usually through the Resistance Spot Welding (RSW) process, whereby two or three overlapping sheets are welded by local Joule-effect heating [2].Dual-Phase (DP) steels are widely used, low alloy steels with a microstructure consisting of ferrite and martensite, obtained from a final heat treatment which consists of heating at an intercritical temperature and then quenching. [3,4]"

Jan 1, 2012

By Mark Jolly, Nasim Soleimanian

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

Jan 1, 2013

By Rong Yang, Qijie Zhai, Wenbin Xia, Changjiang Song

"Tills paper focus on the influence of carbon content and cooling rate on the microstructure and phase formation of Fe-Mn-C alloys under near-rapid solidification. When manganese content is about 11wt.%, more s-martensite can be obtained with cooling rate increasing when carbon content is 0.14wt.%, the formed phase changed from a phase to y phase when 0.74wt.% carbon is added to the samples, and when carbon content up to 2.1wt.%, carbide can be obtained in the sample. A host of stacking fault, which attributes to the strain-induced martensite, can be observed in the sample. The microhardness increased with cooling rate increasing, and under the same cooling rate, the microhardness of samples with 0.14wt.% carbon is highest.IntroductionTo obtain high performance materials is eternal pursuit of material science research. Material scientists have explored many new ways to obtain high performance materials from long time ago. Rapid solidification is one of most popular ways to produce advanced materials by obtaining metastable phases, because it is widely known that the solidification of metals in metastable phases gives access to a whole range of materials with novel properties [1]. Furthermore, nowadays metastable materials have been extensively used in many fields, for example, many of our modem high performance materials such as steel products or aluminum alloys for aeronautical applications are in the form of metastable rather than stable phases [1]."

Jan 1, 2012

By J. K. Brimacombe, I. V. Samarasekera, B. G. Thomas

"Mathematical models have been developed for the processing of static cast steel ingots and are app1ied to investigate the mechanisms for the formation of panel cracks. Panel cracking is an intermittent but persistent defect that causes affected steel ingots to be scrapped. A two-dimensional, finite-element, heat-transfer model was formulated and employed to calculate the temperature distribution in both large and small steel ingots during the various processing stages from initial casting to the start of rolling, including solidification, cooling in the mold and in air, reheating in the soaking pit, and subsequent air cooling. The stress state in the ingot arising from the calculated temperature variations was then determined. This involved the development of a transient, elasto-visco-plastic, finite element, thermal stress model, including the effects of phase transformation volume changes and kinetics creep, and temperature-dependent, mechanical properties. The results of the mathematical model predictions of temperature and stress were then used to determine the mechanisms and to suggest solutions for two different types of panel crack formation. Mid-face panel cracks apparently form during air cooling when the mid-face surface temperature is between the Arl and 500~C. Off-corner panel cracks appear to initiate internally during the early stages of reheating but do not propagate to the surface until much later. IntroductionPanel crack formation in static-cast steel ingots is a defect that has been plaguing the steel industry for several decades. Although the problem is intermittent, it is also serious since affected ingots must be scrapped. Panel cracks are manifested as two distinct types of cracking problems. ""Mid-face"" panel cracks are found exclusively in small, 2 to 6 ton, medium carbon steel (0.3 to 0.7% C) ingots and usually exhibit a single, continuous, longitudinal crack down the center of one of the ingot faces as shown in Fig. l (l). ""Off-corner"" panel cracks often form roughly oval, discontinuous crack patterns on the wide faces of large, 20 to 30 ton ingots as seen in Fig. 2 (2). They affect only low carbon steels (0. l to 0.2% C) with high manganese content. Both defects affect only aluminum-treated steels and are caused by a combination of intermediate temperature ductility loss involving aluminum-nitride precipitation and thermal stress generation. The ductility problem has received a good deal of attention which was the subject of a recent review (3). The present study was undertaken to investigate the thermal stress aspects of the problem through the development of mathematical models of heat transfer and stress generation in static-cast steel ingots. The ultimate objective was to elucidate the mechanisms of formation for both types of panel crack and to evaluate possible solutions to the problem."

Jan 1, 1986

By Marcelo B. Mourão

The reduction of iron ores by solid carbon, when both are agglomerated together in the form of pellets, has important kinetic advantages. Although several studies have been performed on the subject, some points on the controlling mechanisms need clarification. There is a big scatter in the values of the apparent activation energy reported in the literature, and this may be due to factors like heat transfer, flow of gases in the reduction system, pellet size and composition. This work is concerned with the effect of several parameters on the reaction rate. The parameters studied were temperature (in the range 1173 K to 1423 K), carbon type (coke or charcoal), pellet size, gas flow rate, catalyst action of the produced metallic iron and added sodium carbonate. It has been shown that the values of the apparent activation energy can change according to the reduction conditions employed, and hence any modeling effort will have to take account of these parameters. EPD Congress 1994

Jan 1, 1994

By Kenneth N. Pike

The need to comply with environmental regulations and increase production has resulted in modifications to the East Penn blast furnace operation. Changes made include furnace design modifications, closed loop water cooling with heat recovery, automated weighing and charging, automated tuyere punching, ammonia scrubbing of tail gases and improved metal and slag handling to minimize environmental impact. These changes have resulted in a marked increase in yearly production and compliance with many of the air, water and solid waste regulations.

Jan 1, 1990

By Mitsuhiro Ito

"To allow various wastes containing high levels of chlorine to be used as alternative raw materials for Portland cement, two practical methods of chlorine removal were developed. In the first method, chlorine is extracted from the wastes during the cement manufacturing process. In the second, ash-dust waste with high chlorine content is first washed and then dehydrated to cake before being introduced to the cement manufacturing process. This cake can be used as an alternative for some cement raw materials. By combining the two methods, various wastes previously considered unsuitable for recycling due to their chlorine content can often now be used in cement manufacturing plants. As such, these methods represent a major contribution to environmental protection as well as a solution to problems relating to the diffusion of heavy metals and dioxins from cement plants.1. IntroductionWaste generation levels have risen rapidly in recent years. in both the consumer and industrial sectors and today, the need for effective, efficient waste management is one of the most pressing and serious problem of today's society.The Japanese cement industry has reacted to the increase in waste generation by using certain materials as alternative raw inputs or fuels for cement production, in an effort to contribute to society and conserve energy resources.These wastes often contain non-negligible levels of chlorine and heavy metals, however, both of which are unsuitable for cement production. Depending on the element content, Heavy metals have a particularly negative effect -on cement quality; in addition, they can be released into the environment. Chlorine, on the other hand, is contained in large amounts in incinerated ash from household wastes as well as in certain plastics. Both substances are considered impediments in cement-production, not only because they reduce the quality of the cement produced but also because they impair operating safety on cement production lines.To address this problem, two practical technologies have been established for separation and recovery of chlorine components during cement pre-processing and production. This paper introduces the application of these technologies with a special focus on incinerated ash from urban wastes, a representative form of waste material having notably high concentrations of chlorine, heavy metals, and dioxins. We also outline the technologies enabling this material to be used as an alternative input to cement production."

Jan 1, 2000

By Eugene Jak

Copper sulphide processing technologies face increasing pressures associated with decreasing concentrate grade leading to increasing thermal inefficiency and lower productivity. Impurity concentrations are on average increasing, creating potential environmental risk and additional treatment costs. In copper flash smelters dust, partially oxidised materials and fume formed from the condensation of volatile impurities, are routinely recycled to the feed. In the converting stage the heat balance is maintained by charging anode reverts and other inert materials. In both cases, the thermal energy available from sulphide oxidation is not fully utilised or optimised. The productivities of both smelter and converter stages can be potentially increased through the addition of a high copper, low iron, low impurity precipitated copper product. Calculations are carried out for fayalite smelter and calcium ferrite converter slags using an optimised FactSage thermodynamic database. The potential for significant increases in smelter and converter productivities using existing technologies are predicted.

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 Thomas Havlik

It is proposed to realise the direct leaching, during which will be generated elemental sulfur and not sulfate or sulfuric acid as end product, under conditions that sulfur will not cover the leaching surface and Hot hinder the leaching course. The following improvements have been considered: -use of organic sulfur solvents -ultra high-frequency leaching -ultrasonic leaching -use of surface detergents or surfactants in leaching processes -simultaneously crushing and leaching These proposals are under investigation and preliminary results are promising

Jan 1, 1996

By R. M. Westcott

A two-electrode, direct current, slag resistance furnace (SRF) has been constructed and operated to selectively reduce the zinc and lead contents of non-ferrous slags. The experimental SRF is equipped with multiple methods of gas/solids injection for both mixing and reaction. A computer is used to position the electrodes and for data acquisition. A geometric factor correlation was previously developed at Columbia University for calculating the electrical resistance on the basis of furnace geometry and slag conductivity. The experimental SRF was used to test this correlation.

Jan 1, 1994

By Norihiro Murayarna

Hydrothermal synthesis of K type zeolite was carried out by using coal fly ash as a raw material and KOH as an alkali source. The change in various physical properties of the obtained zeolite, such as the kind of zeolite crystal, cation exchange capacity, surface structure of zeolite and particle size distribution were investigated through the overall reaction of zeolitization. The reaction mechanism of K type zeolite from coal fly ash was investigated from these results in this study

Jan 1, 2002

By James C. Sever

"With the advent of high energy costs and increasing concern for the environment leading to the incorporation the C02 life cycle as a criteria for the material used in a finished product, it is beneficial to analyze the plant and the process used in producing a raw material in order to identify practical, economic energy recovery opportunities. To this end a study was made of the proposed Nevada Clean Magnesium, Inc. Tami-Mosi reduction facility. Each source of waste heat is listed together with the assessment for potential co generation or direct recovery. The overall impact on energy requirement and C02 generation is provided.IntroductionHistorically metal reduction plants, large consumers of energy, do not recover waste heat. This occurred for many reasons:• Energy costs were low and the capital for a co-generation system could not be justified;• Waste heat sources contained entrained solids or liquids which would inhibit efficient energy recovery;• The exit temperature for the heat source was too low for efficient use by aaqueous Rankine cycle system.The business environment has now changed adding impetus to the recovery of energy previously discarded. Power costs have greatly increased. Global warming and the impact of carbon dioxide on the environment has become an issue which could impact the permitting of a plant. Technology improvements especially the development of a scaling environment waste heat boiler [l] and the development of the organic cycle Rankine cycle recovery system enable up to 70% energy recovery from ""low grade"" heat sources [2].With the inception of Nevada Clean Magnesium, Inc. 's (formerly Molycor Gold Corporation, Inc.)Northern Nevada Tami-Mosi project [3], an opportunity was presented to incorporate energy optimization from the initial design phase."

Jan 1, 2013

The oxidation of ferrous ions by oxygen in sulphate solutions is a very slow process, but it tills long been known that the addition of sulphur dioxide increases the rate of reaction very significantly. The kinetics and mechanism of the process were investigated in the laboratory and the results confirmed the advantage of adding small amounts of sulphur dioxide to the oxygen stream for the removal of iron from solutions. The effect of various parameters on the overall rate of iron oxidation and precipitation was studied. In particular, temperature, acidity and composition of the gas mixture were considered and the optimum conditions for the precipitation of goethite were determined.

Jan 1, 1991

By Isabela Leao Amaral da Silva, Alice Barreto Bevitori, Frederico Muylaert Margem, Victor Bastos da Silva, Sergio Neves Monteiro, Artur Camposo Pereira

"The jute fiber is one of the most rigid natural lignocellulosic fibers, which has since the last decade been investigated as possible reinforcement for polymeric composites. In the present work, the tensile properties of DGEBA/TETA epoxy composites reinforced with jute fibers with different diameters were investigated. Composites with volume fractions up to 30% of continuous and aligned jute fibers were tensile tested at room temperature to evaluate the ultimate strength, elastic modulus and total strain. For each volume fraction, separated fibers with smaller larger diameters were tested. The results indicated that the tensile properties tend to improve with increasing volume fraction of the thinnest jute fibers. The role played by the fiber/matrix interaction was analyzed by scanning electron microscopy.IntroductionThe interest of this research is to develop composites with epoxy resin matrix reinforced with continuous and aligned jute fibers, for applications in various industries, including construction and automotive industry. Conflicts related to the use of non-renewable forms of energy are increasing the interest to enter the market to replace natural materials, synthetic materials synthetics have a higher power consumption in its manufacture [ 1-4].Therefore, applications of natural lignocellulosic fibers obtained from cellulose-based plants are receiving increased attention as an alternative to replace more environmentally correct nonrecyclable materials, energy intensive and glass fiber composites in [5-6]. The use of composites reinforced with natural fibers is a reflection of the concerns with environmental issues such as pollution caused by waste that is not biodegradable or cannot be incinerated and climate change due to C02 emissions associated with the processes of intensive energy and also motivates this work to develop self-sustaining, since natural fibers generate a source of income, especially in developing countries, where most originate, encouraging the cultivation of non-food agriculture [7-9]. Additionally, it is worth also remembering that these fibers come from renewable sources, in addition to being abundant, inexpensive and have a relevant set of mechanical properties [10]."

Jan 1, 2013

By Hee Dong Jang, Hong Yong Sohn, Miguel Olivas-Martinez

"Tetramethylorthosilicate (TMOS), a precursor of silica nanoparticles, is prepared from the waste silicon sludge, followed by the synthesis of silica nanoparticles from the TMOS by flame spray pyrolysis. A two-dimensional multiphase computational fluid dynamics (CFD) model for the flame spray pyrolysis process (FSP) for the synthesis of silica nanoparticles has been developed. The model incorporates the governing turbulent equations of overall continuity, momentum, energy and species mass transport to represent the gas phase and the population balance model (PBM) to account for the silica nanoparticles. The model has been validated with experimental data in terms of gas temperature and average particle size. Introduction Silica (SiO2) nanoparticles are used in various industrial applications, such as catalyst, pigments, thin film substrates, electronic and thermal insulators, and humidity sensors [1]. They are also used as additives in plastics and rubbers to improve the mechanical properties of elastomers, and in liquid systems to improve their suspension behavior. These applications rely on the particle morphology, average particle size, particle size distribution, and phase composition [2]. Silica nanoparticles can be synthesized by wet chemical processes such as sol-gel methods and high-temperature processes such as flame spray pyrolysis (FSP). The FSP process provides a unique control of particle size and crystalline structure and it can also produce high-purity, thermally stable particles continuously with minimal further treatments. The sizes of the flame- made particles range from a few to several hundred nanometers, depending on the operating conditions [1]. The synthesis of silica nanoparticles from organic compounds that contain silicon by the FSP process is of interest because it generates no harmful by-products [1, 3]. Several compounds such as tetraethylorthosilicate (TEOS) and tetramethylorthosilicate (TMOS) can be used to synthesize silica nanoparticles, but most such compounds are expensive. Thus, it is desirable to prepare the precursor compounds from waste materials. In the present study, TEOS and TMOS synthesized from silicon sludge were used as precursors of silica nanoparticles [4]."

Jan 1, 2008

By Dean G. Heitt

"The Rain and SMZ mines from 1987 to 1994 produced a total of22.0 t of gold from a pre-mine reserve of 14.24 Mt of ore grading 2.13 g/t Au.Gold at Rain is hosted within the basal portion of the Mississippian Webb Formation. ·Mineralization is closely tied to the Rain Fault which is interpreted to be the main feeder for the deposit. Multiple collapse and hydrothermal breccia events provided permeability for the mineralizing fluids in the otherwise unreactive siltstones. Major alteration events include: decalcification and dolomitization of the Devils Gate Limestone; and silicification, baritization, argillization and oxidation of the Webb Fm. Six ore types based on XRD and visual rock chip Jogging have been identified: siliceous ore containing >40% quartz and <30% barite; siliceous-baritic ore containing mostly silica but >30% barite; baritic ore containing >40% barite; argillaceous ore containing >40% total clays (including alunite); calcareous ore containing mostly calcite and dolomite; and carbonaceous ore which has significant pyrite and organic carbon. Metallurgical testing of the oxide leach grade ores found that recoveries, on -1.3 cm crushed material, were greater than 70%. Results also found that Rain ore has strong grind dependency due to silica encapsulation.The Rain leach pad was commissioned in 1988, and to date 9.3·Mt at an average grade of0.65 g/t Au have been placed. Life to date recovery, through December 1995, is approximately 51 %, for a total of3.87 t of gold produced. Two major factors have contributed to the low leach recoveries at Rain when compared with the metallurgical testing: 1) More argillaceous ore than expected was placed on the pad especially late in the mine life and 2) approximately 50% of the tons placed were run-of-mine with no agglomeration."

Jan 1, 1997

By Chikabumi Yamauchi, Mitsuru Tanahashi, Jutaro Miura, Takaharu Iwadachi, Toshiharu Fujisawa

"Tue oxidation behavior of molten Cu-Be alloys was investigated by exposing· the molten Cu-Be alloys to various Ar-O2 atmospheres to control the oxygen partial pressure, PO2 = 10 ~105 Pa at 1423 K. The following results were obtained:• The oxygen · partial pressure in gas phase affects the morphology of the oxide formed on the surface of the alloy and · the oxidation rate of beryllium.• At lower oxygen partial pressure, a molten Cu-Be alloy is covered with a homogeneous and compact internal layer of BeO. Thus, the beryllium oxidation rate can be minimized.• By adding a small amount of calcium or zirconium into the molten Cu-0.5 mass% Be alloy, a protective BeO layer is formed even at higher oxygen partial pressure. Thus, the beryllium oxidation rate can be reduced.IntroductionCopper-beryllium (Cu-Be) alloys are well recognized for their unique properties, such as high electrical conductivity, high strength, high fatigue strength, excellent properties at elevated temperatures, good formability and good corrosion resistance. .This extraordinary collection of properties are the reasons why Cu-Be alloys are expected to be ""Key-materials"", which are necessary to further advance science and technology and to be applied in.various fields such as electronic devices, machine parts, repeater housings of undersea optical fiber communication cables, etc.However, a large amount of beryllium is oxidized to BeO in melting stage of the current Cu-Be alloy production process, because beryllium is a highly reactive element. This is one of the ·main factors that negatively affect the production yield and th_e product quality."

Jan 1, 2000