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By George S. Dulikravich

An advanced semi-stochastic algorithm for constrained multi-objective optimization has been adapted and combined with experimental testing and verification to determine optimum concentrations of aJ10ying elements in heat-resistant and corrosion-resistant H-Series austenitic stainless steel alloys. The objective was to simultaneously maximize a number of alloy's mechanical properties. This research will result in a rigorous tool for the design of high-strength H-Series steels and other types of alloys unattainable by any means existing at the present time. Such a material-by-design tool will also be able to reduce or minimize the need for the addition of expensive elements such as Cr, Ni, Co, Nb, Ti, V, etc. and still obtain the optimum properties of an aJ1oy.

Jan 1, 2003

By C. B. Piazzarollo

Ceramic materials exhibit dispersion results after being subjected to various levels of stress, from the point of view of mechanical strength. With the focus on sustainable development and to improve the strength of these material, was incorporated ornamental rock waste into clay in up to 10% in mass to conform some samples, that was fired to 750ºC, 850ºC and 950ºC and submitted to technological tests. This paper presents an analysis of the technological properties of the samples through the use of Weibull statistic to determine which the best firing temperature for these red ceramic materials. The Weibull Modulus indicates a greater homogeneity for samples with 10R at 950ºC.

Jan 1, 2015

By Hongbo Zhu, Jinhui Peng, Linqing Dai

"To optimize the process variables for making direct reduced iron (DRI) by microwave heating, the reduction temperature, reduction time and the ratio of coal to material were studied with the central composite design (CCD) and their interactions on the Metallization rate were also investigated. The predictive polynomial quadratic equations model was analyzed by ANOVA. Optimal conditions of making DRI can be concluded as follows: 28 min at 1139?, the ratio of coal to material is 20.95%. Under these conditions, the metallization rate is up to 97.06%.1. IntroductionThere are some technical problems in making direct reduced iron (DRI) or sponge iron using iron ore concentrates containing coal and lime. In reduction of the iron ore concentrates containing coal with microwave heating, the strength of pellets needn’t to be considered. It reduces the costs and improve quality of materials, but also eliminates the need for pellet preparation process, simplifying the process and achieving a cleaner production.Microwave energy is a clean energy, and has characteristic of selective heating. The speed of heating is also fast. It researched by Chen Jin that when the mole mass of C: O is 0.627 and the microwave power is 15KW, it only spends 15min from 15? to 1021.6? with 1 kg iron ore containing coal with microwave heating [1]. There are many factors affecting metallization rate. In order to find a suitable condition for reduction process, it is necessary to design a series of suitable experiments.Response surface methodology (RSM) is one of the relevant multivariate techniques which can deal with multivariant experimental design strategy, statistical modeling and process optimization [2–5]. It is used to examine the relationship between one or more response variables and a set of quantitative experimental variables or factors. This method is often employed after the identification of the vital controllable factors to find the factor settings that optimize the response. Designs of this type are usually chosen when a curvature in the response surface is suspected. The process optimization of the microwave reduced iron ore was seldom reported in literature. Hence the present work intends to assess the effects of variables such as reduction time, reduction temperature and the ratio of coal to identify the optimum conditions using a central composite design (CCD). The characteristic of product was assessed using scanning electron microscope (SEM)."

Jan 1, 2011

By Kiyoshi Takai

The Para-Eco Incinerator Ash Processing System for cleaning slag has been developed after a seven-year pilot plant study. The major part of the system is an electric furnace heated to 1773 K. The feed material consists of a municipal solid waste incinerator ash mixture containing a reducing agent of a coke and an inorganic flux of calcium and magnesium. With this furnace system, three kinds of products are produced. They are an inorganic molten salt that is slag, molten iron alloy absorbing non-ferrous metals, and fly ash. Due to the reducing atmosphere in the furnace, the slag does not contain any metal components as well as chlorine components just like natural rock and/or aggregate. A retreatment plant modifies this slag into a practically useful aggregate. The plant consists of a slow cooling step for crystallizing the slag as well as a water granulation step. The iron components in the ash are reduced to molten iron droplets, which concentrate at the furnace bottom. The non-ferrous metal components such as copper, chromium, and others are absorbed into the molten iron but not into the molten slag. Volatile metals such as lead, zinc, cadmium and others as well as sodium, potassium, and chlorine go back into the fly ash. A solvent extraction method and/or other appropriate procedures can be used to extract the metal components from this fly ash.

Jan 1, 2003

By R. Hurman Eric

The flow of molten slag and matte and the estimation of the mass of settled matte in electric furnaces is discussed and the action of the electric furnace as a settler is considered. Particle size of the concentrate and its grade are major contributors to settler dimensions. Discussion on the production capacity of the electric furnace with reference to operating current, power input, furnace dimensions such as width and length and electrode diameter are given. These discussions are based on considerations derived mainly from experimentally determined properties of the slag such as its resistivity, viscosity and liquidus temperature. Extension of the design and operating considerations to circular furnace symmetry is also discussed.

Jan 1, 1995

By J. R. Parga

A shortage of landfill space and growing environmental concerns in Mexico are renewing interest in the recyclability of scrap from automobiles. This work describes a pyroumetallurgical process for the recovery of metallic lead from waste lead paste. Argentopyrite concentrate is commingled with lead paste residue and smelted in a fuming process thereby transferring the precious metals into lead bullion. The process consists of smelting lead paste and argentopyrite, sodium carbonate, and metallic iron at smelting temperatures of about 1100 T. The reaction products are slag and molten lead bullion enriched with precious metals. A major feature of this process is the removal of precious metals from the bullion by means of zinc, whereby a silver-zinc intermetallic compound is formed and floats out of the lead. The recoveries of precious metals are about 98%.

Jan 1, 1996

By William R. Opie

Considerable effort by extractive metallurgical research organizations has been devoted recently to developing pollution-free processes for treating copper sulfide concentrates. A number of hydrometallurgical processes are in various stages of development and have been subjected to economic evaluation. Although the hydrometallurgical approaches eliminate SO2 emission problems, they create objectionable effluents and residues, make precious metals recovery complex, and are not very efficient for treating chalcopyrite. Furthermore, they are consumers of considerably more energy than pyrometallurgical processes which produce blister copper that can be electrorefined to commercial grade cathodes. This paper discusses a pyrometallurgical process under development by AMAX Base Metals Research & Development, Inc. (1) The original objectives set for the process development were: 1. Sulfur control of at least 95% with elimination of fugitive emissions. 2. Copper and precious metal recoveries as good as or better than conventional processes. 3. Low capital cost. 4. Competitive operating costs 5. Use of known proven technology where applicable.

Jan 1, 1976

By Sergio N. Monteiro

From the leaves of the sisal plant (Agave sisilana) a relatively strong fiber can be extracted and is nowadays being investigated as a possible reinforcement for polymeric matrix composites. For this purpose, it is important to determine the critical length of the fiber with respect to the matrix to be reinforced. This has never been properly done for sisal fibers in polyester matrix. Therefore, this work characterized the critical length of sisal fibers, with different sizes, embedded in polyester capsules by means of pullout tests. The critical length obtained allowed the sisal fiber/polyester matrix interface shear stress to be calculated. The relevance of these values for polyester composites reinforcement with sisal fibers is discussed.

Jan 1, 2009

By Guo Chen, Xuefeng Liao, Tu Hu, Shengzhou Zhang, Hongying Xia, Jinhui Peng, Libo Zhang

Pine nut shell is as raw material for preparation of high surface area activated carbon (HSAAC) by microwave induced KOH activation. The effects of microwave power, activation duration and KOH/C mass rate (R) on the iodine adsorption capability and activated carbon yield were investigated. Additionally the surface characteristics of HSAAC were characterized by nitrogen adsorption isotherms and SEM. The operating variables were optimized utilizing the response surface methodology and were identified microwave power 738W, activation duration 17 min, and R 4, corresponding to a yield of 46.28 % and an iodine number of 2154 mg/g. The key pore structure parameters of HSAAC such as the Brunauer–Emmett–Teller (BET) surface area and total pore volume were estimated to be 3819 m2/g and 2.09 mL/g, respectively. The findings strongly support the feasibility of microwave heating for preparation of HSAAC from spent pine nut shell by microwave induced KOH activation.

Jan 1, 2016

By Carlos Maurício Fontes Vieira

In the present work a ceramic body, fabricated using a mixture of clays and sand, for roofing tiles, produced in Campos dos Goytacazes, north of the State of Rio de Janeiro in Brazil, was characterized. Characterization was performed by X-ray diffraction, thermo analysis, chemical analysis, particle size distribution determination and plasticity. In addition, technological properties related to water absorption, linear shrinkage and flexural rupture strength were determined in samples fired at 700, 900 and 1100oC. The results showed that the investigated ceramic body has satisfactory plasticity and presents a refractory behavior during firing due to the predominantly kaolinitic nature of the clays.

Jan 1, 2006

By C. Lupi

The electrorefining of primary copper is a well known technology: in this work copper scrap was directly processed in the same way. he copper and copper alloy scrap was previously pressed by means of a 20 tons apparatus in order to avoid pyrometallurgical operations. The samples obtained in this manner showed a good compactness so that they were used as anodes in the electrorefining tests. The tests were carried out on anodes made by copper scrap, copper alloy scrap and a mixture of the two. The electrorefining tests were performed at both 303 and 333 K, in a perspex cell having a volume of 500 ml using a current density of 250 A/m2. The cathode used was always a sheet of pure copper and the electrolyte composition was 40-50 g/l Cu as CuS04 and 150-200 g/l H2SO4. Current efficiency in the range of 92-97% and specific energy consumption ranging from 0.14- 0.20 kWg of copper were reached in all the tests. The refined copper deposits were analyzed by AAS to verify their purity and observed by SEM to highlight their morphology.

Jan 1, 1998

Al2O3,-WC Composite powder for cutting tools was synthesized by self-propagating high-temperature synthesis using A1 powder as a reducing agent. WC, W2C and Al2O3 were concurrently formed in WO3Al-C system. It was found that the complete reaction was achieved with excessive addition of carbon and appropriate processing parameters such as degree of dilution, particle size of aluminum, compaction pressures of green pellets and carbon source. The final product which was leached by 50% HN03+HF diluted solution was consisted of Al2O3-55wt% WC having 2-3um of mean particle size.

Jan 1, 1999

By S. Malinov, J. J. McKeown, W. Sha, S. McShane

"A model is developed for prediction of fatigue stress life S-N diagrams for Ti-6Al-4V alloy at different conditions, using Artificial Neural Network (ANN). Different factors which have influence on the S-N diagram are involved as input parameters of the NN, namely microstructure, environment, texture, test/work temperature, surface treatment and stress amplitude. As the output the S-N fatigue diagram is simulated and plotted.The model is based on standard multilayer feedforward neural network. The NN is trained with a comprehensive data set collected from the literature, using Levenberg-Marquardt training algorithm in combination with Bayesian regularisation. A very good performance of the trained Neural Network is achieved. Good correspondence between ANN"" prediction and experimental S-N diagrams is observed. Using the model S-N diagrams for different conditions are predicted and analysed. Graphical User Interface is developed for use of the model. We believe that the model will be important for practical applications in solving various problems on fatigue behaviour of the titanium alloy.IntroductionTitanium and its alloys have an increasing range of applications due to their very good combination of mechanical properties, corrosion and erosion resistance. They are currently finding widespread applications in many industries due to their desirable and versatile properties. Most important among the alloys is Ti-6AI-4Y. Jet aircraft manufacturers are the principal 'consumers of Ti-6Al-4V and it is often specified for critical parts, the failure of which could result in the loss of an entire system. A generic class of Ti-6AI-4V has been developed over the past years and it has become the best understood of all the titanium alloys. The advantages of titanium alloys include: (i) low densities, giving very attractive strength to weight ratios allowing lighter and stronger structures; (ii) superior corrosion and erosion resistance in many environments; (iii) high temperature capability. Although the titanium materials are still considered as expensive materials, for many applications the cost of titanium alloys can be justified on the basis of their desirable properties."

Jan 1, 2001

By Rongshan Qin, Dengfu Chen, Yan Zhao, Mingtu Ma, Yang Li, Xinming Wan

A two dimensional cellular automaton (CA) model coupled with finite element (FE) method has been developed for simulating the formation of solidified microstructure during beam blank continuous casting, which represents columnar and equiaxed dendrites growth in the case of detailed secondary cooling boundary conditions. In this model, a new adaptive mesh division is proposed to couple CA cubic lattice and irregular FE mesh of beam blank. A double-accuracy liner interpolation method is employed to obtain micro CA temperature field via macro FE calculation. The nucleation process and the velocity of dendrite tip are calculated by continuous nucleation model and KGT model, respectively. Moreover, the preferred orientation of dendrite growth is determined using a probabilistic model. The effects of super heat and casting speed on the microstructure characteristics are analyzed. This model can be applied to optimize processing parameters for beam blank continuous casting basing on microstructure evaluation.

Jan 1, 2015

By Thor Pedersen

Elkem's technologies for the processing of waste materials, dusts, sludges and other residues, are based on the use of their Multi-Purpose Furnace as the primary processing component. The Multi-Purpose Furnace? is an electric slag resistance reduction furnace equipped with a hot media, Modular Freeze Lining and Elkem's proprietary, air tight electrode seals. The oil cooled? freeze lining allows specific heat fluxes 2 to 3 times higher than furnaces lined with conventional refractory. Reduction activities taking place within the furnace are free from the reoxidation potential of infiltrated air as Elkem's electrode seals are positively gas tight. Small quantities of highly concentrated off gas of controlled composition are produced to suit the requirements of downstream processing. The high electrical thermal efficiency achieved by generating heat within the slag itself, combined with the ability to operate at high melting rates and intense power density, makes the Multi-Purpose Furnace 9 an unique implement for the design of furnace products. These characteristics are utilized in the processing example cited, "Elkem's EAF Dust Processing Technology", which combines two proven technologies in an economically feasible system for the recovery of contained metal values from K061 wastes at the same time producing a disposable slag product. The portion of the example dealing with the condensation of zinc was prepared with the assistance of Imperial Smelting Processes, Limited of Bristol, England with whom Elkem has a non- exclusive license.

Jan 1, 1990

By Ron Bernard

HW Process Technologies has successfully developed and commercialized various applications utilizing Engineered Membrane Separation (EMS?) systems for the processing of acidic copper hydrometallurgical solutions and wastewaters. Copper hydrometallurgical EMS? applications include water balance control and increased copper concentration in heap and dump copper leach operations, tankhouse bleed stream treatment to separate/recover copper and cobalt from iron, and removal of PLS/Electrolyte suspended solids/colloids to eliminate "crud" formation during copper SX/EW. Similar applications are underdevelopment to provide ionic separations in copper refinery bleed streams, copper smelter acid plant streams, as well as organic/LIX removal from aqueous electrolyte and raffinate streams. Copper mine wastewater EMS? applications include treatment of copper leach solution contaminated groundwaters for copper recovery and treatment of unwanted heap/dump drainage to provide enhanced precipitation, a smaller precipitation plant, improved operating costs and better quality discharge water, particularly in terms of TDS and sulfates. A discussion of the EMS? technology and general separation results on typical process solutions and wastewaters will be presented. HW Process Technologies, Inc. commercial installations treating copper pregnant solutions and leach solution contaminated groundwaters are in-place at an old Asarco smelter/refining operation, Mexicana de Cananea copper mine, and a major U.S. copper mine, with several additional installations pending. Several case studies, including results from a selection of these installations, will be included with detailed capital, operating cost, and system payback data.

Jan 1, 1999

By cheng Peng-fei, TANG Hai-yan, guo Xiao-chen, LI Jing-she, Liang Yong-cang, Zhao Baojun

The origin and evolution of non-metallic inclusions for Al-killed casing steel during EAF-LFVD- CC process were studied by industrial tracer experiments. The formations of Al2O3 and MgO·Al2O3 micro- and macro-inclusions from ladle slag were analyzed by theoretical calculations. The results show that micro-inclusions were formed during deoxidation and temperature decreasing in the process of casting, most of the macro-inclusions come from entrapped ladle and mold slags. In addition, most of the Al2O3 formed were modified into 12CaO·7Al2O3 and 3CaO·Al2O3 inclusions which are liquid at steelmaking temperature. MnS cannot be fully modified to CaS and it was only wrapped outside the alumina or calcium aluminate in the form of (Ca,Mn)S with the amount of Ca-Si wire fed during the test.

Jan 1, 2016

By Shekhar Bhansali, Shyam Aravamudhan

"This paper reports on the design and simulation results of a silicon bulk-micromachined diaphragm-type piezoresistive pressure sensor capable of operating linearly over a wide dynamic range (0-1000 meters of water). The piezoresistor elements of the sensor are arranged in a wheat stone bridge configuration to achieve a higher output response. Simulation results (output voltage and sensitivity analysis) obtained using coupled MemPZR-MemMech module of the CoventorWare2003 Finite Element tool are presented. The effect of diaphragm size, diaphragm thickness and thickness of the piezos on output sensitivity were analyzed and optimized to get a linear response over the wide dynamic range.IntroductionThe physical and biological processes in the ocean are critically influenced by ocean parameters (pressure, salinity and temperature). Thus there is a need to develop inexpensive and reliable sensors to continuously measure large volumes of sea-space over long time spans. A key component in any such system will be a pressure/depth sensor. This sensor is routinely employed in marine applications such as wave and tide gauges, tsunami detection, platform leveling etc. More significantly, pressure measurement is needed for depth determination. Depth sensors are vital for remote operated vehicles (ROVs), profiling instruments and towed arrays.Several techniques have been routinely used in the past to measure pressure in the marine environment [1-3]. In general, the pressure sensor design is based on a flexible membrane as the spring element for the sensing pressure [4]. The deflection of the membrane, induced by the applied pressure, is converted into an electrical output through a component that is sensitive to diaphragm deflection (capacitive coupling) or associated stresses (piezoresistors, strain gauges). The temperature compensated pressure measurement can be readily converted to depth using"

Jan 1, 2004

By Huasheng Chen, Gaifeng Xue, Jing Zhang, Mingsheng He, Bin Liu, Yexian Ouyang, Shoujun Peng

Based on the investigation and study of the topography, microstructure and composition of the buildups which form in the surface of carbon sleeve in continuous annealing furnace for lowand medium-grade non-oriented silicon steel produced by CSP process, combined with production process of silicon steel, the mechanism and major causes for forming buildups of carbon sleeve are discussed from the factors such as CSP process, the quality of carbon sleeve and so forth. Meanwhile, some countermeasures to reduce the formation of the buildups are put forward.

Jan 1, 2015

By R. J. Mitchell

Results from investigations into impurity distributions over cathodes are presented with implications for various sampling methods, Selection of an optimum treatment procedure for the test sample is outlined. The impact of both these studies on the development of an in-house method for sampling Isa Process cathode is discussed. The economic compromise actually undertaken, satifying wants and needs to sustain confidence in high grade cathode purity is detailed.

Jan 1, 1987