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By S LeClair

Intelligent manufacturing involves intelligent, product-directed systems that facilitate the on-line, real-time generation of an improving product process cycle. A first step in the journey relates to self-directed systems which have the ability to reason and create their own processing paths in response to varying product and process conditions encountered during the process. This paper discusses an application of self-directed process control in the manufacture of graphite-epoxy laminated composites. An Air Force team involving researchers and production personnel have caused the development of a system now in use at the Air Force Logistic Center at McClellan Air Force Base in Sacramento CA. The paper discusses results and lessons learned in the process of trying to speed the implementation of research efforts which show significant potential of improving the product quality in less time and at less cost

Jan 1, 1992

By Klas G. Hultbom

Mercury is present as trace contaminant in many raw materials for metallurgical plants. When such materials are treated with pyrometallurgical processes the mercury is volatilised. Mercury has a high vapour pressure, even at low temperatures, and therefore it is removed only partly by normal gas cleaning processes. The Boliden Norzink scrubbing process removes elemental mercury by converting it to calomel. It is widely used in the base metals industry. This paper gives examples of the application, and also outlines the background for the development of the process. Another technology developed by Boliden for mercury removal is the Selenium filter. This is a fixed bed filter based on the reaction between elemental gaseous mercury and selenium, by which mercury selenide, HgSe, is formed. The mercury selenide is a highly stable compound with extremely low solubility in water and very low vapour pressure. Mercury is removed selectively without any side reactions. Special applications for the selenium filter technology include mercury removal from gases containing sulphur dioxide and geothermal off-gases.

Jan 1, 2003

By John Wallace

"Monitoring compound semiconductor crystal growth using multifrequency eddy currents for sensing illustrates some of the extreme problems of measurement and interpretation that are not often seen in metallic systems. Using sensor arrays and scanning sensors have produced a qualitative and quantitative understanding of some of the high temperature electrical conductivity mechanisms in several compound systems. A detailed review of the CdTe/CdZnTe data is presented showing some of the complexity in the data as opposed to what is found in elemental semiconductors.HistoryThe most common goal in the use of eddy current measurement in crystal growth is to deter-mine the curvature of the liquid solid interface during growth to test if the heat transfer estimates of the thermal design were adequate for single crystal growth[l]. This aim could be met but represented only a small fraction of the data that was produced observing a growth cycle. A secondary consideration was what could be discovered in the recorded data about the growth and subsequent heat treatment as the boule cooled. This is usually a more difficult task because a crystal growth process is not a controlled experiment so much as a process that continually sees modification. Using a sensor arrays or a scanning loop has produced a qualitative and quantitative basis for understanding some of the high temperature electrical conductivity mechanisms. The implication of the these measurements of electrical conductivity variations are important in that they reflect the complex defect states that will occur on cooling and heat treatment following crystal growth. In contrast to the complex behavior of the conductivity of these compound semiconductors in the solid and liquid state we have the very well characterized system silicon to compare. Initially the interest on using eddy currents to monitor compound semiconductors came from G. Westphal at the Texas; Instruments Company in 1987 to monitor aspects of growth and compounding of GaAs. This was followed by work on solution growth of HgCdTe with D. Witter. The initial interest in the use of eddy cur-rents for monitoring CdTe crystal growth came from Prof. Wilcox at Clarkson University in the practical interest to determine and control the crystal interface curvature during vertical brigdeman growth. The first actual work was done by one of his former students. G. Neuge-bauer at the II-VI Corporation which was carried on by G. Rosen at Clarkson and R. Shetty at II-VI Corporation and with A. Socha at Johnson-Matthey Electronics. The work on CdTe extends over four years and yielded sufficient data to allow one to evaluate the utility of the information produced as compared to what could be obtained from monitoring an elemental semiconductor such as silicon."

Jan 1, 1997

By Qian Li, Haiyan Leng, Kuo-Chih Chou, Haoyuan Xiao, Zhigang Yu

Magnesium borohydride and Magnesium alanate were synthesized by mechanochemical metathesis reaction. The thermal decomposition behaviors of Mg(BH4)2-nMg(AlH4)2(n=0.5,1) systems were investigated as potential hydrogen storage materials. The results showed that the systems started to desorb H2 at 120 ℃ and desorbed 3.9 wt. and 4.9 wt.% H2 below 300 ℃ when n equals 0.5 and 1, respectively, while individual Mg(BH4)2 started to desorb H2 at 250 ℃ and desorbed only 0.82 wt.% H2. Because of the exist of the Mg(AlH4)2, the isothermal desorption kinetics of Mg(BH4)2 in the Mg(BH4)2-0.5Mg(AlH4)2 systems was 50% faster than that of pristine Mg(BH4)2. In addition, the re-hydrogenation rates also increased 49.4% and 37.9%.

Jan 1, 2015

By Victor Stancovski, Uday Pal, Stephen C. Britten

"An in situ electrochemical technique for measuring the concentrations of easily dissociable oxides in slags at temperatures between 1200-1600°C is being developed. The technique utilizes a partially-stabilized-zirconia solid electrolyte (PSZ), which conducts oxygen ions, to separate a reference-gas compartment from the slag of interest. Three types of measurements are currently under investigation which yield different information concerning the slag phase and hence will be combined into a single amperometric device for monitoring the properties of easily dissociable slags.Type I utilizes an open-circuit-voltage measurement between the reference gas and the slag phase. Type II utilizes a potentiostat to apply a direct current potential step or sweep between the inner and outer compartments of the electrolyte, driving oxygen ions from the slag into a reference gas. With the use of open-circuit-reference electrodes, the resulting current-potential profile reveals the dissociation potential and concentration profile of dissociable oxides such as those of iron, manganese, and chromium. Information on the transport properties of the cations can also be generated from these measurements. Type III utilizes a potentiostat with reference electrodes to carefully electrolyze a known volume of slag by removing large quantities of oxygen ions from the slag to the reference gas. The coulombs of charge removed at different applied potentials can be used as a direct indication of the concentration of each dissociable oxide species present within the slag."

Jan 1, 1997

By R. S. Krarner

Fly ash, a by-product of coal burning power plants, poses a major problem for the utility industry since most fly ash must be landfilled. These quantities may represent as much as 20% of the total material going into landfills. A major problem with fly ash utilization is that although the ash consists of useable components, ash composition can vary depending on the types of coal burned and plant operating conditions. Ash is first characterized using SEM, image analysis, and chemical methods. Processing techniques were developed to separate ash into various components including cenospheres, magnetic spheres, carbon, and clean ash. These products are again evaluated for various utilizations before being used to produce valuable products such as mullite, activated carbon, fillers in plastics, and concrete.

Jan 1, 1994

By Xianzhong Hu, Qingbo Yu, Qin Qin

"Oxy-fuel combustion is one promising option among different CO2 capture technologies. The object of this work is to show the effect of CO2 dilution on the laminar flame speed, flame structure and reaction pathway for methane oxidation at O2/CO2 atmosphere. In this paper, kinetic simulations were made using CHEMKIN with GRI-Mech 3.0 mechanism, which was validated by experimental data of laminar flame speeds. The reaction pathway of CH4/O2/CO2 mixture was derived from reaction flow analysis. Results showed that CO2 decreased the flame speeds, lowed concentration of major intermediates and increased flame thickness. The major chemical pathways of CH4 to CO2 have not changed at O2/CO2 atmosphere comparing with O2/N2 atmosphere, but contributions to major intermediates formation from each related elementary reaction have changed a lot. In addition, the secondary chemical pathways of CH3 oxidation became different at O2/CO2 atmosphere.IntroductionNowadays, as the global economy is developing fast and the pollutant levels (especially global warming gases) are increasing, a lot of researches are focusing on new technologies which can cut greenhouse gas emissions [1]. New technologies have been developed, such as high Mild combustion, flameless combustion and Integrated Gasification Combined Cycle (IGCC) technology. Oxy-fuel combustion using carbon dioxide as dilution of oxygen is considered as a promising approach for reducing CO2 emission. The properties of CO2 in flue gas are different from N2 in air. On one side, the transport, thermal and radiative properties of CO2 are different from N2 in air. On the other side, CO2 is not inert but directly participates in chemical reactions and recent researches [2-5] also present the chemical effects of CO2 on oxy-combustion. For these differences above, the characteristics of oxy-combustion are not alike with traditional combustion. It is necessary to develop the investigation of oxy-combustion.In all combustion processes, laminar flame speed is an important parameter, which links to combustion behavior. Analysis of this parameter can provide a better understanding of the effect of CO2 dilution in the process of oxy-combustion. Several investigations of laminar flame speeds of oxy-fuel flame have been improved, including experimental measurements and numerical computations. A.A.Konnov et al. measured the flame speeds of oxy-methane and oxy-ethane mixture using the heat flux method with a flat burner [6-8]. V. Ratna Kishore et al. used heat flux method to measure the adiabatic laminar flame speeds of hydrogen [9] and H2/CO mixture [10]. Adiabatic laminar flame speeds of hydrogen in O2/CO2 atmosphere are much smaller than in O2/N2 or in O2/Ar. The burning velocity of H2/CO mixture decreased with increase in CO2 content in mixture. Jeongseog Oh et al. [11] used Bunsen flame to measure the laminar flame speeds of premixed oxy-methane mixture with angle methods in atmospheric condition (300k, 1atm). The results were SL=29.1cm/s and SL=29.5cm/s respectively derived from oxy-methane from CH* images and Schlieren photos."

Jan 1, 2014

By S. Peng, Vaughan R. Voller

"Free boundary problems are a common occurrence in materials processing operations. An important example is the filling of material into molds. This paper looks at filling problems associated with polymer processing, in particular Resin Transfer Molding (RTM) and Compression Molding. A general, single governing equation is developed which on numerical solution provides predictions for the position of the polymer front in the mold during filling. Both fixed and deforming finite element solutions are developed. Application to polymer filling test problems reveal that the fixed and deforming grid scheme are accurate and compare closely with each other.IntroductionProblems arising from the analysis of material processing operations often involve the tracking of a moving boundary, on which a balance conditions needs to be met, or the locating of a free surface that defines the solution domain. Material processing examples of so called ""free and moving boundary problems"" include; the tracking of solidification/melting fronts[l], the tracking of the metal/gas interface during the filling of a mold[2] and location and shape of a skull (freeze line) in a melting furnace[3].Computational solution of free and moving boundary problems usually fit into one of two classes, viz.1. Fixed grid scheme: In which the spatial domain is covered by a fixed grid (mesh) of node points and the solution uses an auxiliary variable (e.g. a local liquid fraction) to track the moving boundary or locate the free surface.2. Deforming grid scheme: In which the grid in the spatial domain is continuously deformed (or adapted in a steady state problem) such that a specified set of grid points lie on the moving boundary or the free surface.Details on the basic underlying features in these two classes of solution can be found in the excellent monograph by Crank [4]."

Jan 1, 1994

By S. Ellor

The development of models of INCO's Copper Cliff operations using a computer spreadsheet program is discussed. Empirically developed metallurgical relationships were utilised. The paper concentrates on models of the pyrometallurgical processes but discusses applications such as optimisation of operating parameters, evaluation of feed changes and custom or recycle materials processing. The models were initially developed using a spreadsheet program on a personal computer. The requirements of plant engineers and process operators for significant increases in operating speed led to the transformation of some of the modules. The paper is presented in two parts: 1. The development of the modules using a spreadsheet. 2. The transformation of a module into a high speed tool for process control. The application of the technique to other pyrometallurgical processes is discussed.

Jan 1, 1992

By T. S. Montgomery

The performance of carbon-magnesia brick in electric arc furnaces (EAF) is interpreted in light of their observed optical microstructures. Features at the bricks' hot faces were protruding periclase grains, metal globules, graphite-metal contacts and linear void patterns. These features were com-pared to similar features previously seen from microstructures of basic oxygen furnace (BOF) refractories. Modes of formation were sought; an attempt was made to interpret their influence related to wear mechanisms.

Jan 1, 1982

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 Batric Pesic

Adsorption of gold on activated carbon from gold bromide solutions was examined as a function of pH, particle size, carbon amount, initial gold bromide concentration, bromine concentration, temperature, and various cations and anions. pH did not have any effect below pH=6. Above pH=6, pH had dramatically negative effect. The adsorption results satisfied a first reaction order model. The reaction rate constant was proportional to the inverse of carbon particle radius. It was also proportional to the amount of carbon, and independent of initial gold concentration. Temperature had a very little effect at pH=l. At pH=8, the activation energy was a function of the extent of a reaction, increasing with the extent of a reaction. Cu, Fe, Ca, Mg, and Na cations and sulfate, chloride and bromide anions did not have any effect on gold adsorption. Bromine had a very negative effect on gold uptake.

Jan 1, 1991

By H. Y. Sohn, M. Y. Mohassab-Ahmed

"As part of research to develop a novel flash ironmaking process using reduction of iron ore concentrate by natural gas or hydrogen, sulfur and phosphorus distribution ratios between MgOsaturated slag and iron were determined in the temperature range 1550-1650°C under three different gas atmospheres: H2/H2O, H2/H2O/CO/CO2, and CO/CO2. The distribution coefficients of sulfur (Ls) were 4.0, 2.0, and 0.8, respectively, under these atmospheres. The distribution coefficients of phosphorus (Lp) were, respectively, 8, 17, and 20 under these atmospheres. In the flash process over -25 wt% P and S volatilize during ore concentrate downward flight in the reactor shaft in addition to avoiding coke. Therefore, iron produced by the flash ironmaking process would have much lower sulfur contents than the typical hot metal produced by the BF.IntroductionGiven the issues related to large carbon dioxide emissions and energy consumption in the existing ironmaking technologies, a novel flash ironmaking technology was conceived by Sohn [1-3] at the University of Utah. This technology is the first ironmaking process that will convert iron ore concentrate directly to metallic iron in-flight. This process will produce iron directly from concentrate without requiring pelletization or sintering and avoid the need for coke. In addition, this process concept takes full advantage of the fine particle size of concentrate with a large surface area, which permits rapid reduction by a gas. In this novel ironmaking process, potential reductants and fuels are H2, natural gas, and coal gas. Therefore, an iron-slag bath is expected to be at equilibrium with gas atmospheres of mainly H2/H2O or CO/CO2/H2/H2O, respectively, corresponding to the use of H2 or natural gas/coal gas. Since the effects of an H2O- containing atmosphere on slag properties have not been studied before, it is critical for the development of the novel flash process to determine these effects. In H2-H2O-CO-CO2 gas mixtures under ironmaking conditions, H20 was found to have the most pronounced effect on the slag chemistry [ 4, 5]. In addition, it was found in this laboratory that water in the gas atmosphere affected the distribution of Mn between slag and molten iron [6]. Most previous work used CO/CO2 gas mixture to control oxygen partial pressure (p02) [7, 8]. Others used only inert atmospheres [9], although Kor and Richardson [10] used a mixture of C02/H2 to control p02. For phosphorus, previous research focused on Ar [11], Ar-CO mixture [12], CO [13], CO/CO2 [14] or N2/CO [15]. Therefore, it was necessary to investigate the effect of water vapor content in H2-H2O-CO-CO2 mixtures on the equilibrium distribution of sulfur and phosphorus between CaO-MgOsatSiO2-Al2O3-FeO- MnO (0.2-0.8 wt%)-P2O5 (0.1-0.9 wt%) slag and molten iron as part of the development of the novel flash ironmaking technology."

Jan 1, 2014

By Akira Yazawa

The continuous converting has attractive advantages, but further experimental studies on the slag are required, when the process is considered thermodynamically. The summarized experimental results, obtained with iron silicate slag and with ferrite slag and results relating to actual operation are described and discussed in this paper. At first, equilibrium relations at controlled oxygen potentials among three melts of silica-saturated iron silicate slag, white metal and copper are investigated. The results obtained for slag agreed with the thermo-dynamical predictions. Namely, to suppress a magnetite separation, the system should be at high temperature; in the case of the S02 gas of 10 kPa, for example, magnetite did not separate from the slag at 1300°C, but at 1250 and 1200°C the slag was saturated with magnetite even at lower SO2 pressure. Copper losses caused by dissolution of its oxide increased with increasing 5O2 pressure, and were slightly lower than those reported in previous papers without the matte phase. When the continuous converting slag does not contain any appreciable amount of silica - in contrast to the conventional smelting slag ferrite slag would form, but there was no published fundamental work on-ferrite slags. Hence, the melting behavior and activities of the system CaO-Cu2O-Fe2O3 have been investigated. The liquidus diagram in nitrogen atmosphere was, constructed using both thermal analysis and quenching method. The low liquidus temperature region without magnetite separation was found in the part of low content of Cu2O in the section Cu2O-CaO-Fe2O3 and Cu2O?Fe2O3¬CaO?Fe2O3. The activity of Cu2O in the system was also measured. Slags, composed-of CaO, Cu2O and Fe2O3, in platinum crucibles were equilibrated at 1250°C and controlled oxygen pressures. After quenching, the-composition of slag and platinum crucible were determined qualitatively. On the thermo-dynamic analysis of the results, iso-activity lines were drawn, and it was shown that the slag in the converting furnace of the Mitsubishi process exists in an adequate region of the composition triangle.

Jan 1, 1976

By Y. H. Liu

Several foaming aluminum samples of different density were prepared in a semi-industrial scale experimental system. Their properties such as the energy absorption characteristics, mechanical properties, heat conductivity and acoustical properties were measured. The results showed that the foaming aluminum with a density of 0.5 to 0.6 g/cm3 has the best energy absorption and this makes it suitable as the ensuring bar of the automobiles and also as a cushion material for the engine. The foaming aluminum with a density of 0.25 to 0.4 g/cm3 has the best acoustical properties and heat conductivity resistance, which is suitable for the door filling material, the ceiling and the partition of the car engine.

Jan 1, 2003

This report presents overview of the authors' results of thermodynamical investigation of some important metallurgical processes and phenomena. Among them: carbo thermal reduction of silica, and boron oxide, silicon carbide obtaining from different precursors, investigations on copper and manganese ores processing, investigations on pollution from different sources. Special attention is paid-to thermodynamical approach to investigation and estimation of multi component multi element compositions stability, developed by the authors. Also are discussed some auxiliary but' important for the thermodynamical investigations issues.

Jan 1, 1997

By Daoxin Wu

In this paper, the rutile TiO2 were prepared under air, Ar and H2 calcination atmosphere by low temperature hydrolysis using Tetrabutyl titanate (C16H36O4Ti) as raw material. Powers were characterized by X-ray diffraction, UV-vis diffuse reflectance and X-ray photoelectron spectroscopy. The influence of the calcination atmosphere on the photocatalytic reactivity of rutile TiO2 for oxygen production was investigated. The photocatalytic reactivity of rutile TiO2 prepared under air, Ar and H2 atmosphere was compared under ultraviolet and visible light radiation with Fe3+ (c=8.0mmol.L-1) as electron acceptor. The results showed that rutile TiO2 prepared under Ar and H2 atmosphere had higher photocatalytic activity for oxygen production than that prepared under air atmosphere. The oxygen production rates under ultraviolet irradiation were 427.5, 378.2 and 357.0µmol.l-1h-1 respectively when rutile TiO2 was prepared under Ar, H2 and air atmosphere. The oxygen production rates under visible light irradiation were 78.2, 52.2 and 13.5µmol.l-1h-1 respectively when rutile TiO2 was prepared under Ar, H2 and air atmosphere.

Jan 1, 2008

By Christoph Sagadin

Corrosion mechanisms between high melting synthetic ferronickel slags and refractory were investigated. The used slags were prepared by mixing and melting of specific oxides. Substrates of the applied refractory material and specimens of FeNi slags were heated in a hot stage microscope up to 1650 °C. The experiments were performed under a defined gas atmosphere of 60% CO and 40% CO2. A further examination of the formed phases between slag and refractory occurred by scanning electron microscope. The investigations indicate that the slag penetrates between magnesia grains and partly dissolves magnesia. Spot analyses show that iron diffuses into the magnesia grains, which transform to magnesiawustite, meanwhile SiO2 forms different types of olivine like forsterite and monticellite. Thermodynamic calculations confirm the formation of these phases. The combination of practical lab scale experiments and thermodynamic calculations should finally contribute to an improvement of the refractory lifetime and performance.

By Malti Goel

"Technology advancements in fossil fuel based energy generation and consumption are currently being aimed at minimization of CO2 emissions. To attain energy security, India must accelerate the pace of economic development, while achieving reduction in CO2 emissions per unit of energy consumed. It would need access to advanced coal utilization technologies to be demonstrated on indigenous coal characteristics. Of specific importance would be: improvement in coal quality, increasing energy efficiency and suitability of other CO2 sequestration technologies for reducing CO2 footprints. There is need to address related risks and financial burden through adoption of policies and regulations including the issue of open access in energy research. In this paper, seven important areas of strategic plan that need to be pursued for managing CO2 emissions in steel energy sector in India are discussed.IntroductionWorld is facing a crisis of climate change, which follows in the footsteps of global energy and environment crises. Accumulation of carbon dioxide from the generation and utilization of energy is leading to greenhouse warming and climate change. The global warming is causing the boundary between four seasons to be fuzzy and resulting in more spiky weather. Significance of its impact on environment is also determining the technology development needs in various sectors of economy for taking remedial measures.To respond to climate change concerns, the steel industry is undergoing a transition. It is at the threshold of a rapid change in technology as it targets innovation to achieve 50% reduction of CO2 emissions per ton of steel produced. Fossil fuel use is the main contributor of increasing concentration of carbon dioxide in the atmosphere. The control of air pollution and CO2 capture are thus relevant for a coal based industry, whether thermal power plant or a demand side energy intensive industry. World steel production has shown phenomenal increase in first eight years of 21st century increasing from 780 Mt in 2000 to 1343 Mt in 2008 [1]. It was merely 28 Mt in 1900. The global CO2 emissions from steel industry are also increasing and became 2550 Mt (3-4% of total GHG). Indian industry contribution was 161 Mt (15% of direct emissions from industry). It is likely to grow further to keep pace with the accelerated economic growth of 8-9% per annum."

Jan 1, 2010

By Takahiro Furuzono

Saganoseki Smelter and Refinery of Pan Pacific Copper Co., Ltd. started treating copper anode slimes using a unique hydrometallurgical process in chloride media in 1997. The process comprises the following stages, decopperizing, wet chlorination, solvent extraction for gold, silver chloride reduction, and separate reduction stages that treat the gold extraction raffinate with sulfur dioxide gas. Precious metals and rare metals in the copper anode slimes are dissolved in an aqueous solution of hydrochloric acid by oxidative leaching, which is termed wet chlorination. Gold is efficiently extracted from the chlorination liquor by dibutyl carbitol in the solvent extraction stage. Gold is reduced by oxalic acid from goldloaded dibutyl carbitol and recovered as gold powder. The gold powder is cast directly into granules or ingots of more than 99.99% purity without electrorefining. Selenium is recovered as a selenium residue by reduction with sulfur dioxide gas and refined through vacuum distillation. The plant was designed to process 132 tonnes of copper anode slimes per month and has a current capacity of 206 tonnes per month due to several enhancements. Compared with the conventional process, the hydrometallurgical process described here provides some advantages, in particular, a higher product quality, shorter gold-retention time, and reduction in environmental load.