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By Y. Wang, L. Liu, G. Xu, Y. Lv J. Sheng H. Zhang

In order to increase the service life of large scale coke dry quenching furnaces, the damage mechanism of lining was investigated, and the structure and properties of lining refractories used in cooling section were researched. The results showed that the abrasive wear volume of lining bricks at one fourth height section under skew tunnel was smaller than other sections. The wear loss of mullite brick and dense clay brick used in the lining of cooling section were respectively 8.02 cm3 and 11.65 cm3 in fifteen minutes. The mullite brick was laid with clay brick alternatively. By the different wear rate, the surface of lining was rough and uneven in the later service life, and short brick was easily dropped from lining. During the service, the basis wore off more easily than the aggregate. It is necessary to improve the wear resistance property, which will increase the service life of cooling section’s lining for coke dry quenching furnaces.

Jan 1, 2016

By Cong Wang, Siyang Long, Pengcheng Zhang, Haibin Zuo

This paper introduced the research progress of microwave treatment on coal. The mechanics of microwave treatment mainly include thermal effects and non-thermal effects. Thermal effects, which lead to cracks and changes of pore structure, attribute to the selective heating of microwave. Non-thermal effects involve the removal of oxygen functional groups, improvement of coal rank and decomposition of minerals. Therefore, microwave treatment of coal has a lot of potential applications, mainly including drying, desulfurization, improvement of grindability, enhancement of coal-water slurry property and change the combustion and gasification properties.

Jan 1, 2016

By Niels Verbaan, Ralph Fitch, Charlotte Forstner, David Dreisinger

A process has been developed to extract gold, silver, indium, gallium, lead, copper, zinc, and other metals from a large resource using an oxidizing acid chloride heap leaching technology. The ore is crushed and/or ground to improve reactivity and then contacted with a solution containing NaCl-HCl-NaOCl. The value metals are leached into solution as chloro-complexes. The leachate is treated in a series of separation and recovery processes to produce separate saleable or disposable products. The paper will provide a summary of process development and application to a silver-indium ore from Bolivia. The possible application of the process to other ore types will be presented for discussion.

Jan 1, 2015

By Zhongning Shi, Ramana G. Reddy, Min Li, Zhaowen Wang

Electrodeposition of cobalt from cobalt tetrafluoroborate (Co(BF4)2) was investigated using 1- butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) ionic liquid. The experiments were conducted at 353 K. Chronoamperometry experiments confirm that the electrodeposition of cobalt on tungsten electrode proceeds via three-dimensional instantaneous nucleation with diffusion-controlled growth process. The average diffusion coefficient of Co(II) was found to be 7.5 × 10-8 cm2s-1 at 353 K, which is in good agreement with the estimated value from cyclic voltammetry. The electrochemical deposit was characterized using SEM-EDS and XRD methods. The SEM image shows formation of a dense and compact deposit at - 0.75 V. The EDS and XRD analysis confirm that the obtained deposit is pure cobalt metal.

Jan 1, 2015

By Jilai Xue, Jun Zhu, GermainKouma Ndong, Luxing Feng

High-temperature corrosion behaviors of Fe-Ni-Cr alloy as inert anodes for aluminum electrolysis have been studied. The effect of anodic overpotential on layer growth of anodic surface is specially considered. The corrosion layers on the anodes tested were analyzed using XRD and SEM-EDS to provide a fundamental understanding of the layers growth at metallic anode surface. The dissolution of the scale layers on the metal anode occurred with low overpotential, while AlxM3-xO4 spinel phase within the scale layers was found with an increased overpotential. A mixture of multiple MyO layers existed on the anode substrate. The results may be useful for understanding and controlling the corrosion behaviors of Fe-Ni-Cr anode for potential application in aluminum electrolysis.

Jan 1, 2015

By Liu bing-guo, Peng Jin-hui, Guo Sheng-hui, Kong dong-cheng, Hu jin-ming, Zhang Li-bo

The novel technology of calcination to prepare triuranium octaoxide（U3O8）from ammonium uranyl carbonate in microwave fields was investigated on the basis of the temperature rising characteristics of ammonium uranyl carbonate, triuranium octaoxide (U3O8), and their mixture. The result of experiments show that ammonium uranyl carbonate had weak capability to absorb microwave energy, while triuranium octaoxide has the very strong capability to absorb microwave energy and the sample temperature increased rapidly with an increase mixture ratio of triuranium octaoxide. The optimal calcination conditions were as follows: microwave power 700 W, calcination time 10 min and 60 g in this experiments range, respectively. Under these conditions the value of total uranium and 4 U of triuranium octaoxide was 84.28% and 31.02%, respectively. It is feasible to prepare triuranium octaoxide by calcination from ammonium uranyl carbonate, which mixed with small amounts of triuranium octaoxide under microwave fields.

Jan 1, 2015

By Lan Li, Izaak Williamson

"The efficient separation and storage of CO2 from power plant flue gases can reduce the amount of CO2 released into the atmosphere and mitigate global warming. Potential candidates for industrial applications are solid sorbent materials. Crucial factors to control the efficiency of porous sorbent materials include the framework and pore structure, and the chemical and physical reactivity of CO2 within the pores. Computational modeling approaches, based on density functional theory (DFT) and van der Waals-DFT, have been applied to nanoporous solid – manganese dioxide a-MnO2. We found that the types and charges of cations as dopants in the a-MnO2 and the concentration of CO2 influence the structural features of a-MnO2, which control its CO2 selectivity performance within the flue gases.IntroductionCarbon capture and storage is a technique to separate large quantities of CO2 from power plant flue gases before being released into the atmosphere. Porous solids are a potential candidate as sorbents to “trap” CO2 through chemical or physical adsorption on their porous surfaces[1]. Such separation efficiency is determined by the size and shape of its pores and by the interaction between the porous surface and the gas adsorbates. The incorporation of cations into the pore can act as a means of structural support and alter the pore diameter to be comparable to the kinetic diameter of the gas adsorbate, such as CO2.A porous solid of particular interest for CCS is manganese dioxide a-MnO2, an octahedral molecular sieve (OMS) composed of edge-sharing MnO6 octahedra that are linked into a nanoporous framework[2]. The framework consists of (1×1) and (2×2) tunnels, referred to as OMS-2. Due to the larger tunnel size, cations and gas adsorbates prefer to reside along the (2×2) tunnel axis of the OMS-2. As seen in Figure 1, a potassium cation K+ is located in the (2×2) tunnel, known as cryptomelane-type MnO2. Its pore diameter of ~ 4.6 Å gives it a good CO2 selectivity performance, because the diameter is comparable to the kinetic diameter of 3.3 Å for CO2[3]. Alternatively, replacing potassium K+ with other cations, e.g. barium Ba2+, sodium Na+ or lithium Li+, in the OMS-2 tunnel is of great research interest, due to the effects of their concentrations, types and charges on the CO2 selectivity efficiency and sorption hysteresis phenomenon[2,4]."

Jan 1, 2014

By Pertti Koukkari, Nagendra Tripathi, Karri Penttilä, Justin Salminen

A computational fluid dynamic model for a novel flash ironmaking process based on the direct gaseous reduction of iron oxide concentrates is presented. The model solves the threedimensional governing equations including both gas-phase and gas-solid reaction kinetics. The turbulence-chemistry interaction in the gas-phase is modeled by the eddy dissipation concept incorporating chemical kinetics. The particle cloud model is used to track the particle phase in a Lagrangian framework. A nucleation and growth kinetics rate expression is adopted to calculate the reduction rate of magnetite concentrate particles. Benchmark experiments reported in the literature for a nonreacting swirling gas jet and a nonpremixed hydrogen jet flame were simulated for validation. The model predictions showed good agreement with measurements in terms of gas velocity, gas temperature and species concentrations. The relevance of the computational model for the analysis of a bench reactor operation and the design of an industrialpilot plant is discussed.

Jan 1, 2014

By Jilai Xue, Jun Zhu, Germain Kouma Ndong, Qiaochu Liu, Luxing Feng

"High-temperature oxidation and corrosion behaviors of Ni-Fe-Cr alloy as inert anodes for aluminum electrolysis have been studied in oxygen and molten electrolyte. The oxidation and corrosion scales on the anodes tested were analyzed using XRD and SEM-EDS. The oxidation rate is found to increase with increasing temperature from 700 °C to 950 °C, which can be approximately described by an inverse power rate function. The oxidation scales at 750 °C, 920 °C and 950 °C contain Cr-rich phase along with FeCr204 and (Feo.6Cro4)203. The corrosion extent of Ni-Fe-Cr anodes in electrolyte is dominated by temperature, which can make the scales thickness double from 700 °C to 750 °C or from 920 °C to 950 °C. Cr and Fe in the scales on the anode in electrolysis corrode preferentially into the molten electrolyte, while the nickel oxides could better sustain the corrosive environment in electrolysis. The results can be useful for developing inert anode material for potential application in aluminum electrolysis.IntroductionThe development of an inert anode for aluminum electrolysis has been a long term goal for aluminum industry. The present process for primary aluminum production involves the reduction of alumina with carbon anodes, forming carbon dioxide:"

Jan 1, 2013

By Peter C. Hayes

"The high temperature reduction of solids through the use of reactive gas atmospheres has application in a wide range of industrially important processes. Whilst significant advances have been made in understanding and describing these processes, some key aspects of the chemical reactions and reaction mechanisms operating in these systems, for example, the transformation from metal oxide to metal, remain poorly understood. A number of different product morphologies have been identified in these reaction systems and the reaction rates have been shown to be critically dependent on the product structure.Theoretical examination of the elementary process steps taking place in the region of the gas/metal/metal oxide interface, combined with electron microscope studies of the resultant product microstructures, have enabled the key process and material variables responsible for the development of the various product morphologies to be identified. By considering i) established criteria for the stability of moving interfaces in a thermodynamic potential gradient, ii) the relative rates of chemical reactions on the oxide and metal surfaces, and iii) key process phenomena and physico-chemical properties of the solid phases, the mechanisms and conditions for the formation of various product morphologies are identified. Interestingly the analysis points to direct analogies between these phase transformations and, the phenomena and microstructures observed in metal solidification, and the potential to develop generic models of these fluid/solid reaction systems."

Jan 1, 2013

By Ma Shao Xian, Li Dong, Li Zhen Guo

"The new type shaft calciner ( SK-10 Serials) is developed and designed by CADRE itself on the basis of the conventional shaft calciner. The actual application in a number of calcinations plants have proven that they are of very good effect. Calcined coke calcining heated by the shaft calciner has a high quality, lower lost by fire. The shaft calciner needs no additional fuel when it is working. Anode Carbon Plant and calcined coke Plant commonly used the shaft calciner in domestic. The waste heat from the shaft calciner can be recuperated to generate electricity and to make the steam for produce. Exhaust waste heat is recovered by 90% or more. The new type shaft calciner's structure is optimized by computer simulation for fire-wall structure, combustion air to fuel ratio, volatile combustion is fully in use, furnace cooling zone structure, the exhaust smoking structure and calciner heat balance. Furnace structure and production operating parameters has been got the best optimized results. This paper introduces the working principle and characteristics of the shaft calciner - the equipment for calcining of the petroleum coke. It also demonstrates measured process parameters of the new type shaft calciner. Through comparison with the rotary kiln and conventional shaft calciner, it proves its own technical characteristics and advantages: higher capacity, high quality products, provides more energy for power generation, equipment operation and maintenance costs lower.IntroductionChina's petroleum coke market is mainly dominated by the delay raw petroleum coke. Rotary kiln and shaft calciner are the main process equipment for calcined petroleum coke. As the shaft calciner burning less, no external fuel, waste heat utilization is high, long service life, the utilization rate in China is more extensive than the rotary kiln."

Jan 1, 2012

By David G. Dixon, Maziar Eghbalnia

"Gold and silver nanoparticles (NPs) were deposited on pyrite at ambient temperature from colloidal solutions prepared by reduction of hydrogen tetrachloroaurate or silver nitrate by sodium sulfide or sodium tetrahydridoborate. The nanoparticles were characterized using Ultraviolet-Visible (UV-Vis) spectroscopy and the experimental spectra were fitted using Mie - Gans modeling. The modified pyrite was investigated using Electrochemical Impedance Spectroscopy (EIS). Electrodes were prepared from both natural and modified pyrite samples and were modeled using an equivalent circuit (EC) based on the EIS data. The comparison of the results revealed a decrease in charge transfer resistance for the ferric ferrous redox couple associated with the modified pyrite. From this behavior it is concluded that the electronic transport between the nanoparticles and the electrode surface over distances in nanometer scale is enhanced. Nanoparticles below a certain size act as quantum dots due to electronic confmement. Decreased charged transfer resistance at the nanometer scale may be caused by electron transport through tunneling mechanism via quantum dots.IntroductionIn recent years, considerable attention has been focused on the synthesis and study of Metal nanoparticles due to their potential applications in the fields of physics, chemistry, biology, medicine, material science and their interdisciplinary fields[!]. When material is nano-sized, the physical properties deviate markedly from those of bulk material, however, this effect is highly dependent on the particle size, interparticle distance, and morphology of the nanoparticles [2].An extremely small region of space defmed in a semiconductor material in order of nanometers is called a quantum dot, a term coined by Reed [3]. The three dimensional confinement of quantum dots can change properties of the excitons in comparison to free excitons in a bulk material [4]. Nanoparticles behave electronically as zero-dimensional (restricted in all three dimensions) quantum dots when the de Broglie wavelength of the valence electrons and the particle are in the same size range.As Reed [3] explains electrons confined in a plane have no freedom to move the third dimension. Those confined in a quantum wire are only free to move in one dimension, and those confined in a quantum dot are not free in to move in any dimension. An electron inside a cube of material IO nm on a side is confined to a point."

Jan 1, 2012

By Riyad N. Ahmad-Bitar, Shadia J. Ikhmayies

"CdS/CdTe solar cells were built by depositing a 200 nm layer of Sn02:F on glass substrates by the spray pyrolysis (SP) technique, a 500 nm CdS:In layer by the same technique and a 1-1.5 µm CdTe layer by vacuum evaporation. The cells were CdCh heat-treated in nitrogen atmosphere for 30 minutes at 350 -.C. The photoluminescence (PL) spectra were measured at the CdS/CdTe interface for two cells with different values of the CdTe layer's thickness at temperature T = 60 K. A deconvolution peak fit was performed from which it is found that the peaks are characteristic of the solid solution CdSxTei-x· The parabolic relation that relates the bandgap energy with the composition was used to estimate x, where xis [S]/([Te]+[S]) and [Te], [S] are the concentrations of Te and S atoms respectively. The results show that the interface is smooth and the change of the bandgap occurs gradually.IntroductionCdS/CdTe heterojunctions represent a combination of materials promising various applications, and for solar energy conversion in the first place [1]. In photovoltaic cells the CdS material acts as a wide bandgap window. Direct bandgap CdTe with high optical absorption coefficient is used as an absorber [1]. Solar cells with efficiencies of 10 to 16% have been obtained with CdTe grown by close space sublimation, electrodeposition, vacuum evaporation and rf sputtering methods [2]. In this work the CdTe layer was prepared by vacuum evaporation because it results with films of minimum impurities, while the Sn02:F and CdS:In layers were deposited by the spray pyrolysis technique because it is a low cost method which enables intentional doping and large area thin films."

Jan 1, 2011

By Neale R. Neelameggham

"Most chemical process plants and metallurgical production facilities have some sort of cogeneration to minimize process energy costs. Use of Alternative Energy Production from sun and wind power with storage can become an integral part of a process plant utility. This will facilitate reduced fossil fuel usage and help minimize thermal emissions. This will be similar to Pollution Control equipment, which have become an essential part of process plants in the past four decades. Conceptual flow sheets of such Process Utility schemes are presented.IntroductionPower is supplied to industries, commercial and residential users. Over the past decade, Electric Utility companies have made major inroads, in introducing alternative energy resources in an attempt to somewhat reduce fossil fuel use in power generation. Now, on a much larger scale than in the early 1980s, residential users, motivated by government provided tax credits, have started installing alternative energy generators such as roof top wind mills or roof-top photovoltaic generators. This will minimize future energy costs, help control thermal emissions etc. This alternative power generation is typically connected to the existing power grid with two way power metering. However, the use of alternative energy generation has not been seen at large industrial sites yet.Paul Scherer Institute, Switzerland and the NREL laboratories in Colorado, are two of the several institutes which have been developing how solar thermal power can be used to supply the endothermic input energy in chemical and metallurgical processes. The theme of this present symposium addresses the above as well as the energy storage needs for such events to become continuous. This paper emphasizes the concept of how alternate energy can be used in the production of materials on a generic sense wherever there is a need for input energy – beyond endothermic process energy - while addressing how to reduce the thermal and carbon emissions.The alternative energy generation using wind or solar source is discontinuous due to the nature of the energy source. They are not only discontinuous but also variable. This necessitates storage of generated power for close to continuous use with variable loads. C Smith, et al pointed out in 2006, that 'the electric power industry has taken notice of the expansion of wind and its potential' in a summary article on integrating wind generation into utility systems.1 In 2009, the 1000 MW wind generation project in Texas had to be postponed to 2013 for lack of transmission.2 There are only a few large MW solar generation units in the US; the projects being slow mainly from lack of adequate storage and redistribution."

Jan 1, 2010

By Ajit Kumar Jaiswal

"Electric Arc Furnace (EAF) being a power-intensive equipment, EAF based industries are highly dependent on scarce electric energy. This is the reason Government of India is highly concerned about this and laid emphasis on the conservation of electric energy.This paper highlights factors contributing to reduction in specific electric energy consumption in EAF and suggests measures not only for power saving, but also for productivity improvement. To name a few, these are proper sealing of furnace, introduction of oxy-fuel burners, foamy slag practice, increased usage of hot metal/DRI, post-combustion of CO gas for preheating of scrap, improved selection & design criteria of electrics, power demand management, and process automation. Few cases also have been cited, where the above measures have helped in reaping significant benefits.IntroductionFor a long time, Government of India had focused on increase in energy supply, in particular, through electricity generation. Now the emphasis of Government of India has shifted from electricity generation to its conservation for following two reasons:??Power plants have become very cost-intensive??By saving energy, more of it can be delivered at lower cost to the consumersPower generating units, transmission & distribution agencies as well as consumers all have roles to play in the area of energy conservation. By energy conservation, we mean curtailing energy requirement by reducing energy wastages and taking up measures to improve energy efficiency of electric equipment/appliances. In almost all cases, this would be economically beneficial.India’s cost-effective energy conservation potential has been estimated by the Planning Commission at 23 per cent of total commercial energy generated ?1?. A national movement for energy conservation can significantly reduce the need for fresh investment in energy supply systems in coming years. It is imperative that we make all-out effort to realize this potential. Whether a household or a factory, a small shop or a large commercial building, a farmer or an office worker, every user can and must make this effort for his own benefit and for the nation’s benefit as well."

Jan 1, 2009

By Olexandr Gydin

The evolution of grain and dislocation structures during cold deformation of the new steel LH800 of Salzgitter AG is investigated in the frame of this work. The main feature of this material is its ability to air-harden by carbon content of about 0.1%. The initial ferrite structure of the metal provides high plasticity at cold deformation and subsequent heat treatment increases tensile strength approximately two times. Described are results of in-situ tensile tests in the SEM. SEM and TEM analysis of grain and dislocation structures evolution in samples, which have been uniaxially deformed to certain strains, are carried out. After statistical evaluation of results the grain elongation against strain is determined. A microstructure of a deep drawn cup is analyzed by means of SEM. A quantitative evaluation of grain elongation on the different cup zones and comparison of these data with prediction results based on tensile tests are carried out.

Jan 1, 2009

By Jing Zhan

The fibrous precursor can be obtained by coordination precipitation process, using oxalate, cobalt chloride and ammonia. The composition and morphology of fibrous precursor were characterized by XRD, IR, DTA/TGA and SEM analysis. The results show that XRD pattern and composition of the precursor with fibrous morphology precipitated at pH=9.0 were different from that of ß-CoC2O4?2H2O precipitated at pH=1.0. The mechanism on the thermal decomposition of fibrous precursor was addressed. The influences of various conditions in pyrolysis, including the temperature, time, atmosphere, and the morphology of the precursor, on the morphology, average size and specific surface area of the Co powders were investigated in detailed. At last, the final product, fibrous cobalt powders with diameter about 0.3~0.5µm in size and 40~60 in aspect ratio, were produced by thermal decomposition at 400~500? in the weak reducing atmosphere. The structure of pores in cobalt powders was capillary tube with open ports and the majority was mesoporous.

Jan 1, 2009

By Shadia J. Ikhmayies

Polycrystalline CdTe thin films were prepared by vacuum evaporation on glass substrates. The I-V plots which were linear were used to find the resistivity. A value of 2.10×106 .cm was obtained. The transmittance was measured in the wavelength range 400-1100 nm. The bandgap energy was found to be 1.48 eV. X-ray diffraction pattern shows that the material deposits in the zinc blend structure with one strong reflection from the C(111) plane. The scanning electron microscope image shows a uniform surface with a small density of large (mµ1£) grains scattered on the surface.

Jan 1, 2009

By Gjergj Dodbiba, Atsushi Shibayama, Toyohisa Fujita, Takashi Shikazumi, Yukio Kato, Kenji Murata

"A new crushing or liberation technique by means of underwater explosion is put forward. This technique is suitable for crushing and liberating various materials, for instance: the electric parts of the discarded portable telephone, CPU from mother-boards of PCs, steel from plastics tubes used as construction materials, waste constructed materials like panels, tungsten carbide scraps, as well as slitting the optical disk (e.g. DVDs), etc. The materials to be crushed are immersed in water and then the explosion is carried out by using only a small amount of explosive. The shock waves in combination with the generated bubbles are very effective in liberating the materials of different densities. It was observed that the metals crushed or liberated by using this technique were leached much faster when compared with the conventional crushing technique. This crushing method can be applied for liberation of many kinds of electric or mechanical tools. Introduction The explosive has been used since Nobel’s invention in 1866. The main practical application of explosion is in the large scale public works, such as dam construction, land development, tunnel, mining and dismantlement of building. The shock wave caused by explosion extremely can generate high pressure able to break the concrete and rock, and other materials. In this study, the crushing and liberation of waste materials was carried out by explosion in water. The idea was to use this technique as a pretreatment stage prior to recycling. The explosion in water can be used to crush hard materials, helping the liberation between different attached materials. The samples used in this experimental work are waste materials such as construction materials, hose, cemented carbide, cellular phone, lithium buttery, DVD-R, etc."

Jan 1, 2008

By W. F. Drinkard

Many in the environmental movement have focused on this element. But, nothing they or anyone does will change the amount of arsenic in the world. This report is on actual commercial plants that we developed and operated to recover or stabilize arsenic values from metallurgical dusts from gold and copper pyro operations and arsenical gold bearing ores. When they were available gold and copper values were recovered. Our experience in arsenic extends over thirty years. My first corporation, Mineral Research & Development Corporation was the first in North America to manufacture the then new CCA (copper-chrome-arsenic) wood preservatives. This class of wood preservatives proved to be so effective that it made wood into an entirely new material of construction. It is not uncommon for wood properly treated with arsenical CCA preservatives to last for thirty; forty, and sixty years. Over a hundred years have been projected in some field tests. Hundreds of thousands of trees have been saved. Millions more trees would have been saved had environmentalists not decided that their arsenic phobia was more important than trees. There are several variations of CCA. The most popular is CCA-C. Its formula is: CrO3 . . . . . . . . . . . . . . . . . . . 47.5% CuO . . . . . . . . . . . . . . . . . . . 18.5% As2O5 . . . . . . . . . . . . . . . . . 34.0% Until recent restrictions were placed on the consumption of arsenical wood preservatives, annual consumption in North America was about 150,000,000 lbs./yr. About 64,500,000 of arsenic as the pentoxide was safely consumed this way. World CCA consumption has been about double the above figures or 300,000,000 lbs. as 100% CCA and 129,000,000 lbs/yr as As2O5. Close to 100% of all the arsenic used in wood preservatives is derived from gold or copper processing. The valence of arsenic required for CCA wood preservatives and many other markets is the same valence that is required for stabilization. The economic challenge is how to get there. We have built and operated eleven plants to oxidize arsenic trioxide to its pentavalent form. Most of these have been classic in that they used a common oxidants such as hydrogen peroxide or nitric acid to achieve this.

Jan 1, 2005