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By Zhang Jianliang, Zuo Haibin, Gao Bing, Wang Zhe

"As a result of the shortage of coking coal and the quality decrease of coke, it is important to know how to make better use of highly reactive cokes. The co-gasification behavior of highly and lowly reactive coke for blast furnace is investigated. The results show that: In the middle stage of reaction, the weight loss ratio of highly reactive coke reacted together with lowly reactive coke is higher than that of it reacted individually. However, the weight loss ratio of lowly reactive coke is lower. The weight loss ratio of highly and lowly reactive coke is almost the same as that of the weighted average. The scanning electron microscope analysis indicated that the reaction degree of surface and interior of lowly reactive coke is relatively uniform with the reaction time increased. And the reaction degree of surface of highly reactive coke is obviously higher than that of interior.IntroductionIn blast furnace iron making process, coke functions as heat supplier, reducing agent, carburizer and skeleton. With development of blast furnace iron making technology, the skeleton function of coke is becoming more and more important in requirements of large scale furnace and high pulverized coal injection. High reactivity coke is usually produced by cheap coal with bad quality, and is not good for blast furnace process. The reactivity of coke is mainly determined by the coals used, and the resource of good quality coking coal is limited and is non-renewable. In order to fulfill the need of blast furnace, a lot of research have been done to improve coal matching using new kinds of coal to enlarge resource, in which coking coal and fat coal are reduced, whereas low price coal with bad caking property are used to lower the cost, and this would inevitably increase the reactivity of coke [1-4] Blast furnace iron making would still be the main stream for a predicted future, and high reactivity coke would correspondingly be used more and more, so it has great importance to study how to use high reactivity coke in blast furnace."

Jan 1, 2013

By S. G. Kumar, R. G. Reddy

"Niobium aluminides offer the advantage of higher high temperature capability compared to other intermetallic aluminides due to the refractory nature of niobium. However, the reaction sequence in Nb-Al system is sluggish and currently there is a great interest in the processing aspects of these materials. In the present study, a systematic investigation was undertaken to compare the effect of different powder metallurgy processing routes on the phase relations and microstructure of 66Nb-22AH2Ti (in atom percent) alloy. The three different process routes adopted were: (i) cold pressing followed by reaction sintering; (ii) cold pressing and hot pressing followed by sintering; and (iii) arc melting, hydride-dehydride process to make the alloy powder followed by cold pressing and then sintering. The samples are analyzed by XRD, Optical Microscopy, SEM-EDS and EPMA. The analysis showed that alloy pellets made from pre-alloyed powders i.e., arc melting followed by hydride-dehydride process, gave good densification and more Nb3Al formation.1. IntroductionTo improve the performance standards of turbine engines, materials scientists are challenged to develop materials that have· high thrust-to-weight ratio with high specific strength, high specific modulus and good environmental properties at elevated temperatures. The conventional high temperature materials like nickel based superalloys are high in density and hence many of the high temperature materials scientists have focussed their attention on intermetallic aluminides like Fe-AI, Nb-AI, Ni-AI and Ti-AI in recent years. The phase relations and properties of alloys based on Fe-AI, Ni-AI and Ti-AI are fairly well known whereas little is known about the alloys based on niobium aluminides."

Jan 1, 1996

By Keizo Uematsu, Satoshi Tanaka, Nozomu Uchida, Yutaka Saito

"Effect of moisture content must be fully understood for controlling the granule compaction of ceramics. It changes the mechanical behavior of spray-dried granules applied for compaction process, and governs the structure and properties of .ceramics. To understand the time-dependent change in processing, the kinetics was examined for change of moisture content for granules placed in a die and the pressed compacts also. The results were explained in terms of apparent moisture diffusion coefficients. They varied non-linearly with the PVA content in the granules. The results were explained through the non-uniform PVA distribution in the granules.IntroductionMoisture must be controlled in compaction process to produce the green compacts having uniform structure. It affects glass transition temperature of binder and thus the deformation behavior of powder granules under an applied stress. Several studies [1-7] have clarified the effect of moisture content on the compaction behavior of granules and the structure of resultant compacts for both die pressing and cold isostatic pressing (CIP) of pre-formed compacts. In these studies, the moisture contents in the system were equilibrated with the humidity in the atmosphere before compaction. In practice, however, the moisture content in the system may vary with time if the relative humidity of surrounding atmosphere is different from what the granules were equilibrated previously. This is very likely case in real production processes. However, the kinetics of moisture change in the granules as well as in the pre-formed powder compacts have not been well studied. For controlling the microstructure in a system, it is necessary to fully understand the kinetics of moisture change and its relevance to packing structure of powders."

Jan 1, 2000

By Geir Wedde, Anders Sorhuus

"Vast quantities of energy are released as heat to the environment from industrial operations. Many countries target waste heat recovery to mitigate CO2 emission. Exhaust gases from industries such as primary aluminium smelting, carry a substantial portion of the waste heat generated. For a cost efficient capture of more valuable heat (higher exergy), heat exchangers should operate on the exhaust gases upstream of the gas treatment plants. Heat exchange surface would be exposed to dust laden gases with risk of fouling. Heat exchangers of innovated design and operation have overcome the potential of excessive fouling rates. Heat exchangers of the ""shell and tube"" design have been demonstrated for exhaust gases from ferroalloy as well as primary aluminium smelters. In addition to the heat recovery, gas cooling results in smaller gas treatment plants with lower costs and reduced emission. The aluminium experience is exampled in the paper.IntroductionIndustrial usage of energy continues to grow as a result of increasing volumes of production, a trend that is likely to continue in the coming decades as living standards keep rising globally. World energy consumption (Figure la) is to grow 49 % by 2035 (ref. 2010) as reported by EIA [1]. The industrial sector consumes somewhat more than 50% of the total world energy consumption predominantly the energy increased demand comes from non-OECD countries in Asia. The industrial consumption by production of metals iron and steel accounts for 14 % and for non-ferrous metals 3 % mostly for aluminium production (Figure lb). Aluminium production will be discussed in this paper as an example of an industry with large quantities of waste heat to recover"

Jan 1, 2012

By Xi-Shan Li, Qian Li, Yong-bin Yang, Li-na Cui, Tao Jiang, Jie Ge

"With regard to control environment pollution in the roasting pretreatment of sulfur & arsenic-bearing gold concentrate, roasting of double-layered pellet was proposed. In the paper, the characteristics of double-layered pellet roasting were studied. Removal and solidification rates of sulfur and arsenic were investigated as primary factors. The result indicated that the removal and solidification rates of arsenic reached up to 95.91 % and 98.95% while the sulfur was 97.19% and 97.90% respectively on the premise of adopting slaked lime as solidified agent at temperature of 6000, the package proportion of 2.14 and roasting time of 3h. However, pyrite and arsenopyrite were transformed to hematite and magnetite and product of solidification mainly consisted of calcium sulfate, calcium arsenate and calcium sulfite within optimum roasting parameters.IntroductionUtilization of refractory gold resources has been gradually concentrated on with the depletion of the gold resources which are easy to deal with in the world [1]. Sulfur and arsenic-bearing gold ore is a typical refractory gold one, in which ultrafme gold is encapsulated in the structure of metal sulfide minerals [2,3], so it gives poor recovery through direct cyanide leaching. These refractory ores need pretreatment before the process of cyanide leaching to undermine lattice structure of pyrite and arsenopyrite containing gold [4] so that the gold could touch with cyanide solution [5]. Among various methods of pretreatment, conventional roasting method is most effective, but this process generates gases such as S02 and As203 harmful to environment. Therefore solidification roasting was proposed to solve this problem occurring in the conventional roasting at the end of last century."

Jan 1, 2013

By Susan A. Fredholm, Randolph E. Kirchain, Elsa A. Olivetti, Jeremy R. Gregory, Jeffrey B. Dahmus

"A general model for evaluating the economic and environmental performance of electronics recycling systems is developed. This model comprehends the three main functions in a recycling system – collection, processing, and system management – and aims to enable quantification of the impact of context and system architecture on the economic and environmental performance of electronics recycling systems. Such a model can be used both to evaluate and improve existing electronics recycling systems, as well as to design and implement new systems. A case study, based loosely on Maine, is presented to show the utility of such a model.IntroductionAs recycling systems for complex durable goods (CDGs), and in particular for waste electronics, become more widespread, understanding the economic and environmental performance of such systems becomes critical, both to enable improvement of existing systems and to inform the design of new systems. However, with the range of possible system architectures and the important role of locational characteristics (context), understanding the determinants of system performance is challenging [1]. To address this issue, a modeling framework to project the economic and environmental performance of CDG recycling systems, based on contextual and architectural characteristics, has been developed.The modeling framework presented here comprehends the three main functions – collection, processing, and system management – which are common to most recycling systems. These three functions are modeled using a variety of modeling techniques and serve as a bridge between inputs related to system context and system architecture, and outputs related to economic and environmental performance. The models developed here are intentionally meant to be both broad, in order to address entire recycling systems, and general, such that many different systems, both real and hypothetical, can be analyzed."

Jan 1, 2008

By V. A. Luganov

During the treatment of raw materials containing arsenic and antimony, problems in the distribution of these elements in the process products occur. In a number of cases in processing of copper-bearing materials, it is possible (or necessary) to obtain speiss. The purpose of the present research is to study the theoretical aspects and analyze the technological possibilities of producing copper-bearing speiss and the subsequent electrometallurgical processing with copper extraction as well as arsenic and antimony utilization. Copper arsenide (Cu3As) and copper antimonide (Cu3Sb) are the main components of the speiss. A thermodynamic analysis of the electrochemical oxidation of Cu3As and Cu3Sb, carried out using Pourbaix diagrams, showed that in a pH range from 0 to 2, oxidation potential 0.45-0.55V, ions of copper and arsenic and antimony trioxide are in the equilibrium. The kinetic study has shown, that with an increase in the polarization potential, the dissolution process changes from chemical to diffbsion control. An increase in temperature stabilizes the electrolysis process due to dissolution of arsenic trioxide forming on the anode. Electrolysis of speiss using a cathode diaphragm with the solution pH = 1-2, current density 150-200 A/m2 and temperature 60-70°C makes it possible to obtain cathode copper with a current efficiency of 95-96% and to remove the arsenic from the process during the electrolyte cleaning process. The arsenic content in the cathode copper did not surpass 0.002%. As the result of the research, a technological flowsheet for copper-lead speiss processing was developed. At the present time this technology is undergoing pilot testing.

Jan 1, 1999

By Jianxun Song, Hongmin Zhu, Qiuyu Wang, Jungang Hou, Shuqiang Jiao, Xiaobo Zhu

This work presents the results of a study on the Ti3+/Ti2+ couple redox potentials vs. Cl–/Cl2 at the temperature range (673 to 1073 K) in fused LiCl-KCl eutectic by direct potentiometric method. Initial concentrations of TiClx in solvents did not exceed 5.0 mol%. Basic thermodynamic properties of the reactions TiCl2+1/2Cl2(g)=TiCl3 were calculated using the temperature dependencies of apparent standard potentials of the couples E* Ti3+ /Ti2+.

Jan 1, 2014

By Kinya Atsumi, Kanjana Khunathai, Hisaya Kato, Hidetka Kawakita, Keisuke Ohto, Katsutoshi Inoue

"Crosslinked microalgae were prepared from the residue generated in the production of biofuel, by crosslinking-condensation in concentrated sulfuric acid. These microalgae were tested for adsorption of various metal ions in hydrochloric acid medium. The crosslinked microalgae exhibited high selectivity for Au(III) over other precious and base metal ions. From an isotherm experiment, the maximum adsorption capacity was evaluated to be 3.25 mol/kg of dry gel for Au(III) which was many times higher than that of the original microalgae residue. SEM and X-ray diffraction confirmed the formation of metallic gold particles, suggesting the occurrence of a redox reaction between surface functional groups on the gel surface and trivalent gold ion.IntroductionSubstantial quantities of precious metals are being used by the electronic industry because of their excellent electrical conductivity and resistance to corrosion. In recent years, recovery of precious metals from secondary sources such as electronic scrap [1,2 ], and leach liquors is being favored because of environmental concerns. Of course, recovery is only practical, if its cost is lower than the value of the metals (gold, platinum and palladium) recovered.Traditional methods of separation and refining do not fulfill this requirement. In order to overcome this problem, attempts have been made in recent years to develop new processes including total leaching in hydrochloric acid containing chlorine gas or hypochlorite, followed by solvent extraction and ion exchange [3]. In the new processes, new solvent extraction reagents or ion exchange resins with high selectivity and high loading capacity are used to simplify the process and to reduce the operating costs."

Jan 1, 2011

By Ray Y. Lin, Sunil G. Warrier

"Low cost processing of metal matrix composites is an essential requirement for this class of materials to be acceptable in commercial application. In an effort to reduce the cost of processing of metal matrix composites, an infrared pressureless liquid infiltration technique has been developed. The salient features of infrared infiltration are that it is rapid, simple and a low cost process. The rapid processing capability causes very little oxide formation on the alloy resulting in both improved wetting and flow characteristics and reduced oxygen contamination in the composite. Thus, vacuum is normally not required. Using infrared inflltration, aluminum and titanium matrix composites have been prepared under an ambient argon atmosphere. Reinforcements in these composites include carbon fibers, silicon carbide Nicalon fibers and Textron's SCS fibers. Microstructural and mechanical test results indicate that completely consolidated composites with good fiber distribution, limited interfacial reaction and high mechanical properties can be manufactured by this process. IntroductionAluminum and titanium matrix composites reinforced with ceramic reinforcements are strong candidates for numerous applications in the aerospace and automotive industries. Aluminum matrix composites are commonly fabricated by either solid state vacuum hot pressing, liquid state pressure infiltration or squeeze casting [1]. Although liquid state pressure infiltration and squeeze casting has significant advantages over solid state processes, the requirement for pressure makes these composites uneconomical for large scale industrial application. Titanium matrix composites are primarily fabricated by solid state diffusion bonding [2]. Pressureless liquid infiltration can significantly reduce the cost of fabrication in both the composite systems. However, during pressureless infiltration processes, several complications concerning the wetting characteristics and chemical compatibility arise."

Jan 1, 1994

By Fan Xiao-Hui, Jiang Li-Juan, Chen Xu-Ling

"In order to solve air leakage of sintering testing cumbersome, inaccurate results, and other issues, the sinter machine air leakage characteristics were studied, and combining the mathematical modeling and the field detection. The temperature before air leakage was calculated by mathematical model, energy balance equation was established according to sintering process, using Adams prediction correction method which has stronge stability and high precision, to solve hyperbolic partial differential equation with astringency problem. The temperature after air leakage is detected by instruments, according to energy conservation calculation the sintering air leakage rate. According to the sintering continuity and periodicity, sintering air leakage location diagnosis expert system was established to judge specific air leakage locations.IntroductionStrengthening of modern blast furnace production depends on the quality of the raw material preparation to a large extent [1]. Technical and economic index of modern blast furnace production is advanced; the most important reason is the use of concentrated feed. Sintering plant is the ""kitchen"" of blast furnace’s concentrate. As we all know, sintering plant is major energy consumption of steel plant, in sinter process energy consumption, the solid fuel consumption of total energy consumption is 75%~80%, power is 13%~20%, ignition and combustion is 5%~10%. To reduce the air leakage of sintering plant is an effective measurement to save energy consumption. At present, our air leakage of sintering compared to the other developed countries is still a long way to go. Japan’s air leakage rate is about 30%, and 35%~60% air leakage of sintering machine at home, a big gap exists between the plants. At present the determination of air leakage is all for manual operation, long measuring period, considerable manpower and resources, and the results are significantly affected by operation. For air leakage of sintering control lag issues, research and development of diagnosis expert system for on-line monitoring model for air leakage and, through this research can reduce the use of detection equipment, detect sintering air leakage, improve the yield and quality of sintering production, reduce energy consumption, and extend equipment life span."

Jan 1, 2012

By Alexandre Bonan

The paper reports on the results of a kinetic study on the oxidation reaction of aqueous free cyanide ions with H202, in the presence of Cu(2+) catalyst. The variables and respective ranges studied were the following: (CN) ° = 10 -100 mg/l pH = 10 -11 (H202/CN) mol ratio = 1 -3 (Cu/CN) mol ratio = 0 -0.25 The results lead to the development of a semi-empirical model whish incorporates both the useful oxidation reaction and the parallel alkaline decomposition of H202.

Jan 1, 1992

By J. B. Wiskel, H. Henein

"A study was conducted to establish the effective heat transfer coefficient for a single molten droplet moving in a gaseous medium. Towards this objective, a series of quench experiments were performed on molten droplets of AA6061 aluminum generated with the Impulse Atomization technique (IAP). IAP is a single fluid atomization process capable of producing powders with a predictable mean particle size and a relatively tight standard deviation under controlled atmospheric conditions. Microstructure analysis of the atomized powder was used to establish the extent of pre-quench solidification. A mathematical model was then employed to correlate the Ranz-Marshall and Whitaker equations with the observed particle cooling behaviour. These equations were found to provide a reasonable estimation of the heat transfer conditions only when the variation in gas thermophysical properties across the boundary layer was accounted for in the model. This model formulation of droplet heat transfer has important implications with regards to active sprays and atomization processing operations IntroductionAn understanding of droplet cooling is important in atomization powder production. It is well understood that dendrite arm spacing is inversely proportional to cooling rate during solidificationl1l. Through modification of the heat transfer conditions during metal atomization, the microstructure of a powder maybe tailored to the end user. However, owing to the complexity of gas flow it is difficult to determine a heat transfer coefficient for a moving droplet. This difficulty is further compounded when complex jets and/or streams and their interactions are considered. To provide a base for these more complicated types of analyzes, two approaches have been employed to calculate the effective heat transfer conditions for a single droplet. In one approach, Megardis [ZJ developed a numerical model to investigate the heat transfer process of a free falling droplet undergoing laminar convective cooling. The effective heat transfer coefficient as a function of angular position was determined by numerically solving the fluid and energy equations for the system."

Jan 1, 1999

By B. Ozturk, K. Ito, R. J. Fruehan

"A simulation model for bath smelting processes for the production of iron was developed which predicts the coal, flux, ore, and oxygen consumptions and the off gas volume, temperature and composition. The model is comprehensive in that it takes into account all of the important variables including coal composition, metal composition, ore composition, slag basicity, post combustion ratio, (PCR), prereduction degree (PRO), heat transfer coefficient (HTC) , flux, scrap charge, and heat losses. Four basic cases were considered: I. 30% PRO-50% PCR; II. 90% PRO-O% PCR; III. 60% PRO-30% PCR; and IV. 0% PRO-50% PCR. Several different coals were considered and a sensitivity analysis of the critical variables was performed. The model also estimates the sulfur content of the metal. The major conclusions included:1. Post combustion significantly reduces coal consumption but above 20% PCR little reduction of FeO to Fe can be performed with the off gas.2. Prereducing to FeO (Case I) and having as much post combustion as consistent with good heat transfer is an attractive process. This process only requires a simple pre reducer, uses less coal, and is relatively insensitive to the type of coal used.3. High off gas temperatures may pose a potential problem. The off gas temperature can be reduced by using an 02-Air mixture for post combustion, limiting post combustion or adding water to the gas.4. The use of CaC03 in place of CaO or of supplemental electricity does not appear attractive.5. The melting unit is theoretically an energy efficient scrap melter. For Case I using 200 kg of scrap as part of the charge the coal consumption decreases by about 80 kg.6. With PCR > 30% the FeO content of the slag is expected to be 2-5%, and the metal will not be saturated with carbon. These factors and the increased sulfur load since coal is the fuel indicate the sulfur content of the metal may exceed 0.25%"

Jan 1, 1988

By Michael S. Moats, Jan D. Miller, Wlodzimierz W. Zmierczak

"For many, hydrogen in a pure hydrogen economy would be like natural gas in today’s energy economy. Unfortunately, hydrogen’s physical properties are unsuited to the energy market’s requirements in terms of packaging, storage, transfer, and delivery. In this paper, a hybrid energy economy that packages hydrogen chemically on carbon atoms from various sources including recycled carbon dioxide is introduced and discussed. For this new hybrid energy economy to become a sustainable reality, the ability to recycle carbon dioxide and use hydrogen to create an appropriate energy product, such as dimethyl ether (DME), is needed. DME is recognized as a potential next generation, “beyond-petroleum”, environmentally benign commodity for energy storage and distribution. It is expected that to maximize the sustainability of the proposed hybrid energy economy, “green” hydrogen will be utilized. The “green” hydrogen would be created by the electrolysis of water powered by renewable energy sources, such as solar, wind or geothermal heat.IntroductionWith the growing concerns surrounding trends in global warming and increasing concentrations of “greenhouse” gases, such as CO2 and CH4, efforts to mitigate the emission of these gases from industrial sources are growing. With respect to CO2, the demonstrations of various capture and sequestration methods are underway around the world.The sequestration of CO2 is mainly focused on storing the gas underground or deep in the ocean. The Intergovernmental Panel on Climate Change (IPCC) estimates that 2000 Gtonnes of CO2 can be stored underground in depleted oilfields, un-minable coal beds and other geologic features [1]. Additionally CO2 may be stored at the bottom of the ocean. The lure of storing carbon dioxide in depleted oilfields or un-mineable coal seams is that an economic benefit (enhanced oil or methane recovery) can offset the costs of gas capture, transportation and storage. Unfortunately, all of these storage methods have potential for the release of CO2 or CH4 back into atmosphere or creating environmental damage (mobilizing heavy metals, disrupting deep sea ecology)."

Jan 1, 2008

By Shiwei Sun, Hongxu Li, Xiangxin Hao, Xie Yang

"Environmental impact assessment of copper metallurgical processes will soon become a compulsory activity in the future. The goal of this work is to analyses the copper metallurgical processes including pyro-metallurgy and hydrometallurgy based on the life cycle assessment method implemented in GaBi software. The evaluation indicators such as global warming potential (GWP), acidification potential (AP), photochemical ozone creation potential (POCP) and human toxic potential (HTP) are taken into account. The results show that the major environmental impact phase in pyro-metallurgy derives from beneficiation because of the largest material and energy consumption. It is also shown that copper hydrometallurgy has significantly lower environmental impact than pyro-metallurgy. Based on the evaluation results, some corresponding optimization methods are recommended to reduce environmental impact.IntroductionCopper is an important metal in modem society due to its wide variety of uses, including electrical wiring, heat exchangers, piping and roof construction and increasingly consumer electronics. Demand for copper has increased dramatically over the past decades, driving production rates almost exponentially. Annual production of copper was estimated to be 20 million tonnes in 2012 with Chinese production at about 6.06 million ton in 2012P1. The production process of copper has environment impacts that often go unnoticed by the producer. Higher production, coupled with declining ore grades, is placing increasing pressure on the natural environment.Sound environmental management helps producers improve their manufacturing technique. LCA is a well-established tool for assessing environmental impact potential and can be readily adapted to map impact potential over time, which can be used to quantify the environment impacts of a product or a process [21. This is achieved by creating an inventory of all the energy and material flows used in the process's life cycle. The results of an LCA can be used to improve the operation of a process so that they have less impact on the environment."

Jan 1, 2014

By S. Katz, V. Stanek, K. L. Moore, E. D. Larsen, D. E. Clark, P. E. King

"Cupola melting is a complex physical and chemical process having a number of nonlinearities which make conventional process control difficult. In addition, sensors for both inputs and outputs of interest to the foundry operator are often difficult or impractical to apply in a production situation. The present work is an effort to control the process using both intelligent and conventional control techniques as appropriate. Neural networks are used as an inverse process model in a cascade, feedforward controller in conjunction with a finite difference model of the cupola. A separate implementation of the neural net serves as a stand-alone visualization tool; it can operate on a laptop computer and is a useful tool for the cupola operator. IntroductionThe goal of the present work is to develop a controller to improve the efficiency of cupola melting. Although cupola melting as a process has a long history, automatic control has been elusive because the process has been poorly understood. The purpose of this four-year program, which has been underway for about six months, is to develop a controller for the cupola process using intelligent and conventional control methods.The Cupola ProcessThe cupola furnace [1,2] is one of the oldest processes for making cast iron, and is still the dominant method. It takes the form of a water-cooled vertical cylinder, as large as 4 m in diameter and 20 m tall. The charge consists of scrap metal, alloying ingredients, limestone, and coke, which serves as fuel; it is composed by weight and fed through doors near the top of the cupola. Air, usually heated and often enriched with oxygen, is blown in near the bottom through tuyeres extending a short distance into the interior of the cupola. As the coke is consumed, the charge drops and melts. A continuous flow of iron emerges from the bottom of the furnace, at rates as high as 100 tons per hour, and. is transferred to casting lines in the foundry. The exhaust gases are drawn from the top of the cupola, where they are processed to meet pollution standards."

Jan 1, 1994

By Felipe P. D. Lopes, Ailton Silva Ferreira, Sergio N. Monteiro

"Environmental issues such as global warming and water pollution are motivating fast changes in scientific and technological paradigms. Special importance is now being given to the so called environmentally friendly materials, which are renewable, recyclable and biodegradable. An example is the natural fibers with increasing industrial applications beyond the conventional uses as baskets, fabrics, ropes and carpets. In addition to traditional natural fibers, others like curaua (Ananas erectifolius) are being investigated for possible use as reinforcement of industrial composites. Since epoxy matrix is not yet incorporated with curaua fibers, the objective of this paper was to study the basic properties of epoxy composites reinforced with different amounts of curaua waste fibers. A comparative analysis aiming at the use of these composites as substitute for conventional building materials was carried out.IntroductionThis new millennium, which initiates with the 21th century, is experiencing a fast degradation of the environment by pollution and climate changes. Most of the problems are related to our methods of development associated with the use of fossil fuels and the energy intensive processing and production of synthetic materials. As a consequence, environmental issues such as global warming and ocean pollution are motivating rapid changes in technological paradigms. One relevant example is the current importance given to natural materials like the lignocellulosic fibers extracted from cultivated plants or found as industrial wastes [1]. These fibers are considered environmentally correct alternatives to substitute energy intensive conventional synthetic fibers such as carbon, glass, nylon and aramid. In addition to the renewable recyclable and biodegradable nature of the lignocellulosic fibers, the low cost and abundance in developing regions are major advantages that justify their increasing application as reinforcement of composites [2,3].In fact, nowadays, the use of natural fibers is no longer restricted to baskets, ropes, clothes and carpets. Industrial composites are introducing these fibers in large technological segments associated with car making, building construction and furniture [4,5]."

Jan 1, 2008

By M. K. Patel, K. A. Pericleous, M. Molaei

"The future trading of carbon credits and increased financial cost necessitates substantial cuts in incidental C02 emissions in the production of metals (iron, steel, aluminum, zinc, lead). Although greener methods of production are being developed, in the short term the use of point-source C02 extraction using existing technology remains attractive. Accelerated natural carbonation, in a fluidized bed is a feasible technological route investigated in this research. CFD modelling has been used to study the efficiency of C02 capture in a fluidized bed reactor containing a CaO solid sorbent. A Lagrangian/Eulerian scheme describes describe CaO particle trajectories and exchange of mass, momentum and energy with the carrier gas, with a typical off-gas composition. Different reactor geometries are considered (with uniform, stepped and gradually expanding cross-section), to maximize conversion for a given particle loading and size distribution (100-200 microns). Removal efficiencies of up to 80% are demonstrated, making this a viable process.IntroductionBased on Intergovernmental Panel on Climate Change (IPCC) reports, the major cause of climate change and global warming is due to a high level of C02 concentration in the atmosphere resulting from fossil fuel combustion, particularly in coal-fired power plants [1]. Carbon capture and storage is therefore the most important action proposed to reduce C02 from combustion flue gases. In this process, carbon dioxide is captured and may then be regenerated as pure C02 and conducted to a permanent storage, or simply stored as a solid carbonate [2]. Capture and storage of C02 has an economic penalty and the main cost of this penalty is associated with the capture plant. Capturing C02 with a lime-based solid sorbent (CaO) is a very promising technique, due to the low cost and the wide availability of the reactant. In this process, the CaO reacts with C02 based on the following reaction in a reactor called a Carbonator:"

Jan 1, 2012

By I. S. Blair

The Mufulira smelter (1, 2,' 3, 4,) is one of three smelters situated on the Zambian Copperbelt to treat concentrates and other intermediate products produced in the area. Two mining companies, Roan Consolidated Mines Limited (RCM) and Nchanga Consolidated Copper Mines Limited (NCCM) each have 51% Zambia Government participation. RCM operates two smelters, one at its Mufulira Division and the other at its Luanshya Dl vision. NCCM operates one smelter at its Rokana Division (5). The Mufulira smelter was commissioned in 1937 with two reverberatory furnaces and four converters. The final product, blister copper, was cast from a holding furnace. In 1952 two anode furnaces and a common casting wheel were installed to feed a new and adjacent electrolytic refinery. In 1956 the smelter was extended to accommodate increasing production from the new Chibuluma mine and expansion at Mufulira mine. A third reverberatory furnace, a fifth converter and duplicate anode processing and casting facility were added. The Copperbelt smelters suffered a loss of production potential when higher ash content coals were used in reverberatory smelting furnaces from 1966 onwards. This, and the planned production increases from Mufulira and other RCM mines, indicated a smelting shortfall of 55,000 tonnes of copper a year in the combined capacity of the RCM smelters.

Jan 1, 1976