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By Yunhua Gan, Xiaowen Chen, Meilong Hu, Haige Li, Yang Tong

Ethanol is a kind of renewable fuel, which can be produced from biomass and applied in many energy areas, such as motorcar. The combustion of ethanol in meso-scale is facing great challenges, such as great heat loss, poor stability, and low combustion efficiency. Electro-spraying technique is an effective method to atomize liquid ethanol due to its great advantage of monodisperse and uniform characteristics. In present study, electro-spraying was applied in liquid meso-scale combustor to produce very small droplet diameter and uniform droplet distribution. Experiments were carried out based on nozzle-ring-mesh electrode structure using pure liquid ethanol as fuel. Electro-spraying characteristics were measured by Phase Doppler Anemometer (PDA) under different nozzle voltages, ring electrode voltages, flow rates, and steel mesh positions. The results may be helpful to the design of new meso-scale electro-spraying combustor using renewable liquid fuel.

Mar 1, 2017

By C. Frias, M. Garcia, G. Diaz

Advances in hydrometallurgy promoted by Tecnicas Reunidas are providing increasingly simple and clean means for controlling the entire lead recycling chain. Used in parallel with pyrometallurgy, these processes allow furnace temperatures to be reduced and fumes and atmospheric pollution to be minimised. Furnace slags are digested, and residues (mainly gypsum) are non-toxic and convertible into marketable products. In addition, the global economy of the process is substantially improved by reducing the operating cost, increasing the lead recovery above 99% and obtaining a 99.99% pure lead product. These new PLACID and PLINT processes may provide the cleanest and healthiest practicable means for recycling lead from batteries.

Jan 1, 2000

By Fumitaka Tsukihashi

Phase diagrams of the CaO-SiO2-FeOx-MgO, Al2O3 systems are necessary for the analysis of copper smelting reactions and sintering process of iron ore. The effect of MgO and Al2O3 addition on the liquidus of the phase diagram of the CaO-SiO2-FeOx system at low oxygen partial pressure was observed. The liquid phase area changed by the addition of MgO and Al2O3 with a changing oxygen partial pressure from 10-8 to 10-3 atm (10-1 to 102 Pa) at 1573K. The effect of Fe3+/Fe2+ ratio on the melting mechanism is discussed.

Jan 1, 2003

By Fumitaka Tsukihashi

Phase diagrams of the CaO-SiO2-FeOx-MgO, Al2O3 systems arc necessary for the analysis of copper smelting reactions and sintering process of iron ore. The effect of MgO and Al2O3 addition on the liquidus of the phase diagram of the CaO-SiO2-FeOx system at low oxygen partial pressure was observed. The liquid phase area changed bi the addition of MgO and Al2O3 with a changing oxygen partial pressure from 10-8 to 10-3 atm (10-3 to 10 2 Pal at 1573K. The effect of Fe3+ / Fe2+ ratio on the melting mechanism is discussed.

Jan 1, 2003

By J. A. Brierley

A biooxidation-heap pretreatment process was field tested to evaluate enhancing gold recovery from a preg-robbing sulfidic carbonaceous ore. Newmont Gold Company&apos;s Gold Quarry sulfidic carbonaceous ore was inoculated with an iron-grown culture of Thiobacillus ferrooxidans to form a 495 ton test heap. Biooxidation was conducted for a period of 100 days. The most active period of biooxidation occurred during the first 40 days of pretreatment? About 35 to 40% of the sulfide was oxidized. The extent of biooxidation was considered good as the ore particle size was relatively large 58% >1?9 cm (&apos;/< inch). The larger particle size ore limited the extent of bacterial activity. The field test demonstrated the ability to conduct biooxidation in a small pilot test heap. Thiourea was evaluated for extraction of gold from the biooxidized preg-robbing ore.

Jan 1, 1995

By Wilky Desrosin, Alicia E. Ares, Carlos E. Schvezov

"In the present research the horizontal directional solidification Zn-Sn alloys (Zn-4wt. %Sn, Zn- 6wt. %Sn, Zn-10wt.%Sn and Zn-30wt.%Sn) was carried out by extracting heat in two opposite directions. For this purpose, ceramic molds, a muffie, a horizontal furnace with two heat extraction systems at the ends, a measurement, acquisition and recording temperature system, eight K-type thermocouples and an electronic recorder were used. The main parameters involved in the columnar-to-equiaxed transition, CET, were: the moment of start and end of solidification at each position under consideration, cooling rates, the average temperature gradients and critical temperature gradients at the CET, the average speed of liquid and solid interphases left and right, advancing in opposite directions. Also, solidification kinetics was found to be different between horizontal solidification two-way heat extractions, with preliminary results of the vertical unidirectional solidification. In the solidification experiments, the velocity and accelerations of the liquidus and solidus interphases usually occurs at the end solidification zone of the samples.IntroductionSolidification of metal alloys, which starts in the external equiaxed region (chill), results in two basic types of structures in a single solidified alloy sample: columnar and equiaxed. The presence of both structures indicates the occurrence of the colunmar-to-equiaxed transition phenomenon[!].Studying the colunmar-to-equiaxed transition, CET, is of great technological interest for the evaluation and design of the mechanical properties of the solidification products. To this end it is necessary to understand the mechanisms by which it occurs. As found in previous studies [2-5], the CET occurs by competition between columnar and equiaxed growth. Mainly is controlled by the parameters of casting, such as the alloy composition, the density of the present nuclei in the liquid, the cooling capacity of the metal I mold, and the degree of convection in the liquid [7-10]."

Jan 1, 2014

By I. Gaballah

The kinetics of oxychlorination of pure CI-2O3 with C12+02 gas mixtures is studied by ThermoGravimetric Analysis (TGA) in non and isothermal conditions up to 1000 °C. The reaction of Cr2O3 with C12+O2 chlorination gas mixtures starts at about 550 °C and the reaction product is CrO2Cl2. The oxychlorination rate of Cr2O3 is almost proportional to the chlorine partial pressure and to the fourth root of the oxygen partial pressure in the chlorinating gas mixtures. At 800 °C, the maximum chlorination rate is obtained using a gas mixture having a C12/O2 ratio equal to 4. The apparent activation energy of the oxychlorination reaction of Cr2O3 is 87 and 46 kJ/mol at temperatures lower and higher than 650 °C, respectively. By varying the chlorine and the oxygen partial pressures of the oxychlorinating gas mixtures at temperatures higher than 550 °C, it is possible to extract selectively the chromium chlorinated compounds from the chromium bearing materials. a. Laboratoire Environnemem et Minéralurgie, BP 40, 54501 Vandceuvre, France, b. École Nationale Supérieure de Géologie, Rue du Doyen Marcel Rouhault, 54501 Vandoeuvre Cedex, France, c. Centre National de la Recherche Scientifique, 3 rue Michel - Ange, 75794 Paris Cedex, France, d. Insritut National Polytechnigne do Lorraine, Rue de la Font de Haye. 54501 Vandceuvre Cedex, France.

Jan 1, 1997

By Edita Vircikova

The best demonstrated available technology (BOAT) for the removal of dissolved arsenic and some heavy metals as reported by USEPA (Contaminants and Remedial Options at Metal Sites, Draft Report, August 1993) (1) is still the chemical precipitation. Coprecipitation with the excess of iron is usually practised because of the availability of iron at low/no cost and also in order to meet the stringent regulatory discharge limits. The arsenic is usually removed with iron because of its common occurence in the mined orebodies and the excellent adsorptive property of the precipitated hydrous ferric oxide compounds. There has been controversy, however, over the long-term stability of the arsenic-bearing ferrihydrite which is produced.

Jan 1, 1995

By B. Abedian, L. M. Racz, S. R. Berry, R. W. Hyers

"The presented work represents an effort to improve understanding and prediction of turbulent flow inside electromagnetically-levitated droplets. We show that the flow field in a test case, a nickel droplet levitated under microgravity conditions, is a low Reynolds number turbulent flow, i.e. in the transitional regime between laminar and turbulent. Past research efforts have used laminar, enhanced viscosity, and k - E turbulence models to describe these flows. In our study, we compare the RNG algorithm to laminar and k - E turbulence model results. We show that accurate description of the turbulent eddy viscosity µr is critical in order to obtain realistic velocity fields, and that µr cannot be uniform in levitated droplets. In the RNG method there are no characteristic length or time scales associated with the flow, thus allowing such anisotropic features to be captured. We perform calculations and analyses for two cases (1) a small, non-deforming, spherical nickel droplet and (2) a deforming, oscillating droplet. In addition to flow field calculations, we compare numerically-obtained surface tension and viscosity values to those obtained experimentally by the oscillating drop technique.IntroductionElectromagnetic levitation (EML) is a containerless processing technique for conductive materials. Its advantages are the avoidance of contamination or chemical reaction at container walls and the ability to perform long-term experiments in a metastable state. Because of its current limitation to small sample sizes, its primary use is in the laboratory. One application of interest is the measurement of thermophysical properties of undercooled liquid metals [1, 2, 3, 4]. In EML, a sample weighing approximately 1 gram is positioned inside an electromagnetic field generated by alternating currents flowing through an axisymmetric water-cooled copper coil. The coil must be designed appropriately so that thesample levitates in a stable manner.Traditionally, mathematical modeling has been performed in tandem with both earth-and spacebound electromagnetic levitation experiments, in order to determine the effect of the magnetic field on material and flow characteristics [5, 6, 7, 8]. These calculations are important because they allow design, planning, and correct interpretation of experiments. In addition, the calculations are of fundamental scientific interest, as they can be applied to other electromagnetic materials processing applications [9]."

Jan 1, 1999

By Rodney Hundermark, July Ndlovu, Lloyd Nelson, Phillimon Mukumbe, Paul van Manen, Whitey Seyanund, Bart Pieterse, Bertus de Villiers, Diale Mokwena

The 2003 redoubling in power to 68MW on the Polokwane Smelter furnace represented a significant intensification in platinum group metal (PGM) smelting. Combined with onerous ‘green’ PGM concentrate smelting requirements, this yielded conditions unusually corrosive to copper coolers and refractories. This presented unexpected operational and design challenges to reliable crucible operation and maintenance. Combined with specific operational control intervention, development of protective coatings has led to the life of water-cooled copper components improving from 9 to 40 months. The furnace matte endwall was extended in 2010 to address accelerated wear of refractories and the potential risk for contact of copper components by superheated matte. An 18 month planned endwall rebuild cycle has been demonstrated (versus catastrophic failure within 9 months). Finally, benefits including lower energy consumption, improved metal recoveries and higher productivity resulting from operational and in-house design developments will be described, that justify “Celebrating the Mega-scale” in PGM smelting.

Jan 1, 2014

By Carlos Maurício F. Vieira, Gabriel Oliveira Glória, Maycon Sidney Gomes de Camargo, Sergio Neves Monteiro, Fábio da Costa Garcia Filho, Maria Carolina Andrade Teixeira, Frederico M. Margem

The society is increasingly the concern about the ambiental impacts, and demand for eco-friendly materials. The composites reinforced with synthetic fibers are been replaced by composites reinforced with natural fibers because of the environmental advantages. Besides the environmental advantages, those fibers have economical and properties advantages, like the low density and cost. Composites with up to 30%of PALF fibers were tested. The analyzed parameters were the loss modulus, the storage modulus and the delta tangent. The test was conducted in the temperature interval from 25 to 195 °C in a DMA equipment operating at 1 Hz of frequency under a nitrogen flow. The results showed that the incorporation of continuous and aligned PALF fibers tends to increase the viscoelastic stiffness of the epoxy matrix. Contrasting this, minor changes occurred in both the glass transition temperature and the damping capacity of the structure as measured by the tan delta peaks.

Mar 1, 2018

By Z. Y. Xie

The visualization techniques were employed for the analysis of computer simulation studies of dislocation core structure in ordered alloys. Atomistic computer simulation was used for the study of the local configuration of the material in the vicinity of the dislocation. Stresses were applied in the simulation in order to study the necessary stress level for the dislocation to move and onset plastic deformation of the material. The results were analyzed in terms of the strain tensor as a function of the position (x, y) in the material with the dislocation located at (0, 0). Various visualization packages are used to plot the invariants of this strain tensor and to visualize the changes that the dislocation core undergoes under stresses until it finally moves.

Jan 1, 1993

By Tracy Morris, Weldon Read, Luis Navarro

"Bismuth is a recognized contaminant in the electrolytic refining of copper that can render many cathodes to be outside ASTM standards and unsuitable for copper rod and other downstream products if not carefully controlled. This paper portrays the performance of Molecular Recognition Technology (MRT) for bismuth removal at the Amarillo Copper Refinery (ACR) and describes how the highly selectivity gel has been successfully used to achieve good bismuth removal and how many pit falls and draw backs have been overcome.IntroductionASARCO operates one of the largest copper refineries in the world at Amarillo, Texas. The main feed for this refinery is produced at the Hayden smelter in Arizona. During the operation of this smelter a variety of metals are carried as impurities in the copper anodes because of the diversity of concentrates and residue products used as raw materials in the smelter feed mix. Even though the impurities are concentrated enough to be detected at the smelter, it is difficult to remove them completely. A simple way to control impurities at the smelter is to minimize the addition of material with a high concentration of impurities to the charge in order to reduce the output of this metal species. All this leads us to have a ""refinery problem"" [1,2,3]."

Jan 1, 2012

By Bernd Kos

The management of waste materials in the aluminum industry is as important as in other basic industries. Due to the high value of the-by products of the melting process and their toxic properties we took the challenge to develop a process technology to reduce the environmental impact and to help industry to get a better yield of their by products/raw materials. In melting operations metal losses due to oxidation are nearly unavoidable, the amount of such losses, however, can be controlled. Aluminum dross actually is a by product and any shop would like to get rid of it in the most economic way. This by product still contains up to 70% valuable metal! In the present work we describe possibilities to separate metal and residues for further processing. Recycling of metal concentrates, selling of dross and dumping of the residues have been the typical solutions up to now. But there are technologies available which are designed to reduce the waste to a minimum or even avoid it altogether. Such alternatives are processing of the dross into materials which can be reused in other industrial processes in order to avoid any dumping. This can be done by separating the metal and the residues by centrifuging and further use of the residues in the chemical or refractory industry. ECOCENT means economical and ecological recovery of aluminum by centrifuging of hot dross. This process, developed by FOCON Austria, is based on the idea of treating the hot dross as quick as possible in a single operation to avoid exothermic losses, intermediate storage and unnecessary handling as well as to save energy. In the ECOCENT process the hot dross is fed without any fluxing salt additions into a converter where the relevant parameters for separation, like temperature and viscosity, will be adjusted. Further big lumps of dross are ground into smaller pieces in order to improve the later separation of the metal. After homogenizing and adjusting the temperature, the hot dross is poured as quickly as possible into a centrifuge. In the ladle or alternatively the mould of the centrifuge the centrifugal forces are used for the separation of aluminum from aluminum oxide, the major constituents of dross. The separated pure metal can either be discharged liquid or as solidified aluminum ring. The design of the device for the production of liquid or solid metal is almost identical. As soon as the centrifuging is finished the liquid aluminum can be poured back into the furnace or can be used for ingot pouring. After the pouring of the metal the "dry" residues are removed just by turning the ladle. Alternatively the aluminum solidifies in the mould and is discharged as a compact ring. The separation of the residues from the aluminum ring is automatic. Due to the batchwise operation the composition of the metal is the same as in the skimmed furnace of origin. The complete treatment cycle needs about 40 minutes. The recovery rate of aluminum is better than 90% of pure metal. This technology is highly flexible by its nature and can easily accomodate various operational requirements. The consumption of energy is more than 50% lower compared to conventional dross processing as the ECOCENT process is using the inherent energy of the hot dross. These extremely good results are not dependent on the aluminum content of the dross even from very dry dross most of the metal can be recovered. The main advantages compared to conventional dross processing are the high recovery rate, the known analysis of the metal and the immediate reuse of the recovered aluminum. The high recovery rate and the pure metal result in a short amortization period. The compact ECOCENT unit needs a minimum of space since extensive handling can be avoided. The electronically controlled process needs no cooling water and is simple, safe and environmentally sound. The residues are free of fluxing salts, their content of metallic aluminum is low and the environmental problems are thus greatly reduced.

Jan 1, 1995

By Dhanesh Chandra

In this symposium, research in the area of energy conversion is presented. This symposium has special significance, as we honor three prominent scientists from hydrogen storage research and development field. In this symposium, the majority of papers presented by international scientists and engineers are in the area of hydrogen storage. Other energy conversion papers include magnetic materials, superconductors, and thermal energy storage materials. Recent developments in light-weight high gravimetric hydrogen density hydrides have led to potential use of hydrides for onboard automobile and other applications. This, of course, is significant from environmental concerns of CO2 and other emissions from the current use of carbon based fuels in automobiles. Thus, it is becoming increasingly important to switch to cleaner alternative fuels such as hydrogen [1]. The Challenge of Vehicular Hydrogen Storage as potential hydrogen energy carriers for vehicular applications, with a driving range of approximately 300 miles, require ~5-13 kg of hydrogen stored on-board. In the United States, Centers of Excellence have been established in metal hydrides, chemical hydrides, and carbon-based materials, and abundant scientific and industrial research is being carried on metal hydrides; only some of the current research from the Centers will be reported here. The European commission, Japan Institutions, and others also have numerous hydrogen storage programs in progress. Several international collaborations have also begun between IEA and IPHE scientists to accelerate the progress of development of practical hydrides. A summary of the abstracts is included in this overview.

Jan 1, 2006

By R. Abel F.

In 1997, Ventanas electrolytic refinery expanded its production capacity from 215,000 to 325,000 metric tons per year. This increase in capacity has involved the treatment of anodes with different impurity contents, changing the operational strategy of the plant. On the other hand, the increasing necessity to accomplish environment conservation rules and quality assuring requirements, has led the plant operation and administration to compete in an advantageous way. The present work describes the results obtained in the startup and in the operation of the ENAMI Ventanas electrolytic refinery expansion, and shows the difficulties which have been faced in the processing of anodes of increasing complexity, in a competitive market and with environment and quality restrictions.

Jan 1, 1999

By Susumu Okabe

Injection metallurgy is widely adopted in various fields of metallurgical operations to achieve high productivity. The Mitsubishi Continuous Copper Smelting and Converting Process employs the top blown lance technique for the continuous supply of solid charges and reaction gases into the molten bath, where the agitated bath contributes to enhance the heat and mass transfer and the increased gas/liquid interface area accelerates the reaction. However, excessive splashing of the molten materials accompanied by the injection may cause an unexpected wear of the furnace lining. In order to estimate the splashing rate quantitatively, and to optimize the furnace design and the blowing condition, a physical model study of the top blown gas injection onto the liquid bath was carried out. An equation of the splashing rate was obtained as the function of cavity size, gas velocity and bath properties.

Jan 1, 1995

By Peter M. DiGiacomo

In situ leaching technology requires information about how injected fluids flow in the rock in relation to the localization of the valuable minerals to be leached. In oxidative leaching of sulfide copper ores, flow channels can be determined by the observation of residual iron oxides. In contrast oxide copper ores do not leave a detectable residue after leaching. Method is developed that allows a selective labeling of the leach residue with fluorescent compounds. The fluorescent zones can be detected in corings after the leaching operation.

Jan 1, 1981

By Zhenbo Zhao

The processes and equipment for INLRFH (Isothermal Normalizing by Utilizing the Residual Forged Heat) of alloy carburizing steel products are presented. It is shown that four key parameters: namely (I) cooling rate before isothermal normalizing, (IT) the lowest cooling temperature before isothermal normalizing, (111) isothermal normalizing temperature and (IV) isothermal normalizing time, should be controlled. The prediction and calculation of these parameters can be achieved on the basis of components treated and the technical requirements of the steel parts by an on-line expert system. The cost-reductions due to the energy savings resulting from implementing this system for automotive parts heat-treatment are most promising.

Jan 1, 1999

By Mamoru Kuwabara

A high-power sound which can transmit through any continuous elastic medium with less attenuation, particularly in liquid allows us to externally control the system of concern by using the acoustic radiation force or the cavitation phenomena. These functions may eliminate gravitational and/or atmospheric constraints which are often encountered in conventional operations for producing clean and advanced materials. This paper outlines the recent development in the field of sonoprocessing of materials. Cold model experiments in some vessels have been performed to simulate ultrasonic operations such as inclusion removal from liquid, degassing of melt, emulsification of two liquid phases, solidification processing, and decomposition of chemical species in waste water. High speed visual imaging is carried out for better understanding of the cavitation phenomena as well as the followed microjets during the processing. The radiation force acting on fine suspending objects in a fluid can be utilized for eliminating or rearranging/orienting the objects in the fluid. Acoustically induced cavitation phenomena in liquid can be utilized as an effective dynamic means to control interfacial phenomena as well as micro- and macro-mixing of liquid. Sonochemical and thermal effects in cavitation multi-bubble can be also useful in a waste water treatment.

Jan 1, 2006