Purification of metals through filtration and electromagnetic separation

The applicability of a high frequency electromagnetic field to the removal of nonmetallic inclusions from silicon and aluminum, and the mechanism of depth mode filtration during aluminum purification were investigated. Electromagnetic separation experiments at frequencies of 63 - 120 kHz and aluminum filtration experiments using both conventional Al₂O₃ filters and AlF₃ coated Al₂O₃ filters were carried out by flowing molten aluminum through, and partly solidified in the filter bed followed by analysis of the metal and filter material. Materials were characterized with an optical microscope and macroscope, scanning electron microscope (SEM/EDX), x-ray diffraction (XRD), electron probe microanalysis (EPMA) and glow discharge mass spectrometry (GDMS). 3D FLUENT CFD simulation was made in support of the filtration experiments. In the high frequency electromagnetic field work, the induced fluid flow significantly enhanced particle segregation either at the wall or at the bottom or deposition close to the top. The electromagnetic particle separation efficiency was significantly improved by higher coil current and longer separation time. Higher frequency also improved particle separation efficiency but was less significant than current or separation time. Filtration results showed that depth filtration of aluminum involves the contribution of three important mechanisms which are (1) collision and interception effect which involves particles transport from the melt and attachment to filter wall, (2) effect of inclusion bridges and (3) interfacial energy between collided inclusions --Abstract, page iv

Numerical Analysis of Melting and Holding Furnaces in Secondary Aluminum Production

En esta tesis, dos hornos de aluminio diferentes se analizan numéricamente: 1) un nuevo prototipo de horno de fundición; 2) un nuevo prototipo de horno de mantenimiento. Estos dispositivos son claves en la producción de aluminio secundario. Los modelos utilizados tienen en cuenta la conducción de calor en las partes sólidas, la convección en el aire y de aluminio fundido, las interacciones entre las zonas de gas-líquido-sólido, cambio de fase de la carga y la transferencia de calor por radiación. Con el objetivo de desarrollar una herramienta de cálculo para asistir en el diseño y escalado de hornos industriales, se evalúan diferentes estrategias de cálculo concernientes a la economía computacional y su precisión de cálculo de diferentes parámetros importantes. Las estimaciones de las temperaturas en los hornos se comparan con las mediciones experimentales realizadas en prototipos reales en ciclos de operación típicos

Process Modeling in Pyrometallurgical Engineering

The Special Issue presents almost 40 papers on recent research in modeling of pyrometallurgical systems, including physical models, first-principles models, detailed CFD and DEM models as well as statistical models or models based on machine learning. The models cover the whole production chain from raw materials processing through the reduction and conversion unit processes to ladle treatment, casting, and rolling. The papers illustrate how models can be used for shedding light on complex and inaccessible processes characterized by high temperatures and hostile environment, in order to improve process performance, product quality, or yield and to reduce the requirements of virgin raw materials and to suppress harmful emissions

Synchronous reluctance motors with fractional slot-concentrated windings

PhD ThesisToday, high efficiency and high torque density electrical machines are a growing research interest and machines that contain no permanent magnet material are increasingly sought. Despite the lack of interest over the last twenty years, the permanent magnet-free synchronous reluctance machine is undergoing a revival and has become a research focus due to its magnet-free construction, high efficiency and robustness. They are now considered a potential future technology for future industrial variable speed drive applications and even electric vehicles. This thesis presents for the first time a synchronous reluctance motor with fractional slot-concentrated windings, utilizing non-overlapping single tooth wound coils, for high efficiency and high torque density permanent magnet-free electric drives. It presents all stages of the design and validation process from the initial concept stage through the design of such a machine, to the test and validation of a constructed prototype motor. The prototype machine utilizes a segmented stator core back iron arrangement for ease of winding and facilitating high slot fill factors. The conventional synchronous reluctance motor topology utilizes distributed winding systems with a large number of stator slots, presenting some limitations and challenges when considering high efficiency, high torque density electrical machines with low cost. This thesis aims to present an advancement in synchronous reluctance technology by identifying limitations and improving the design of synchronous reluctance motors through development of a novel machine topology. With the presented novel fractional slot concentrated winding machine design, additional challenges such as high torque ripple and low power factor arise, they are explored and analysed - the design modified to minimise any unwanted parasitic effects. The electrical and electromagnetic characteristics of the developed machine are also explored and compared with that of a conventional machine. A novel FEA post-processing technique is developed to analyse individual air-gap field harmonic torque contributions and the machines dq theory also modified in order to account for additional effects. The developed machine is found to be lower cost, lower mass and higher efficiency than an equivalent induction or conventional synchronous reluctance motor, but does suffer higher torque ripples and lower power factor. The prototype is validated using static and dynamic testing with the results showing a good match with finite element predictions. The work contained within this thesis can be considered as a first step to developing commercial technology based on the concept for variable speed drive applications.Financial assistance was provided by was provided by the UK Engineering and Physical Sciences Research Council (EPSRC) in the form of a Doctoral Training Award and additional financial assistance was kindly provided by Cummins Generator Technologies, Stamford, UK, through industrial sponsorship of this wor

Modeling and Simulation of Metallurgical Processes in Ironmaking and Steelmaking

In recent years, improving the sustainability of the steel industry and reducing its CO2 emissions has become a global focus. To achieve this goal, further process optimization in terms of energy and resource efficiency and the development of new processes and process routes are necessary. Modeling and simulation have established themselves as invaluable sources of information for otherwise unknown process parameters and as an alternative to plant trials that involves lower costs, risks, and time. Models also open up new possibilities for model-based control of metallurgical processes. This Special Issue focuses on recent advances in the modeling and simulation of unit processes in iron and steelmaking. It includes reviews on the fundamentals of modeling and simulation of metallurgical processes, as well as contributions from the areas of iron reduction/ironmaking, steelmaking via the primary and secondary route, and continuous casting

Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018

Metallurgical Process Simulation and Optimization

Metallurgy involves the art and science of extracting metals from their ores and modifying the metals for use. With thousands of years of development, many interdisciplinary technologies have been introduced into this traditional and large-scale industry. In modern metallurgical practices, modelling and simulation are widely used to provide solutions in the areas of design, control, optimization, and visualization, and are becoming increasingly significant in the progress of digital transformation and intelligent metallurgy. This Special Issue (SI), entitled “Metallurgical Process Simulation and Optimization”, has been organized as a platform to present the recent advances in the field of modelling and optimization of metallurgical processes, which covers the processes of electric/oxygen steel-making, secondary metallurgy, (continuous) casting, and processing. Eighteen articles have been included that concern various aspects of the topic