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By Wallace R. Horn

"MR. CHAIRMAN AND GENTLEMEN :I begin this talk by making a couple of comments which are of the nature of disclaimers.Firstly, and as the Chairman has otherwise indicated, I was neither ""born into"" nor have I spent more than a few years of my professional life in the mining industry. I mention this because many might, and perhaps rightly, consider that an added qualification in presenting a report of what the industry has accomplished. Indeed, I am not here to blindly defend all of its actions and inactions in respect to environmental control over the years. Nor am I here to seek absolution of the industry's past transgressions - if indeed that is the word. Mistakes might be a better one. I concluded some time ago that the effects of those mistakes are too difficult to assess against the sea of errors of our total society. I should mention too that I am not an environmental engineer or specialist - only a portion of my interest is involved with this field. Perhaps this permits a perspective which allows a more accurate and objective view.One further comment here. My job today, as I understand it, is to generally report upon the nature and extent of the response of the metals mining industry to control of the environment. In the case of an industry operating at more than a hundred locations and for various reasons at various stages of progress, it is not an easy job. On the other hand, I wanted to avoid the use of generalities because, especially within the context of environmental or ecological opinion and of the practice of condemnation of industrial segments, I think we've had about enough of generalities until we know far more than we do.Finally, I am quite aware that a statement of future plans to achieve environmental control does not impress or satisfy as many people as it may have done some years ago. Public opinion demands to know what is currently underway, today."

Jan 1, 1972

By S. Bantubani, I. Mc Dougall, S. Arjun, H. Joubert, R. Hansraj

The requirements determining the design of the Söderberg electrode columns used in base metal applications are different to those of other industries. There is a strong trend to position the contact shoes above the furnace roof in order to reduce the risk of water leakages directly onto the furnace bath. Tenova Pyromet has adapted its proven electrode column design for application on base metal electric furnaces based on these requirements. The design modifications implemented as well as considerations regarding the overall electrode-roof-furnace arrangement are discussed. Equally important is the management of the Söderberg electrodes to prevent over or under baking. Tenova Pyromet has developed the AutoFurn™ furnace controller to not only optimise furnace operations, but to improve electrode management. An overview of the electrode management control philosophy implemented by AutoFurn™ is provided, focusing on intelligent electrode regulation, slipping and baking. INTRODUCTION Tenova Pyromet has developed an electrode system for use in base metal furnaces, which builds on the experience that Tenova has gained during the past 30 years with electrodes in the ferroalloy and base metals industries. In base metals applications, an important safety consideration is the minimization of water within the furnace and on the furnace roof. In addition, direct contact between copper equipment such as contact shoes and pressure rings and the contents of the furnace is discouraged. In a 3 phase AC furnace, three electrode columns transfer the electrical energy to the furnace bath. Both Söderberg and prebaked carbon or UHP graphite electrodes are in use in base metal furnaces. In each column, the electrode is held in position by a hydraulic slipping and regulating device, a pressure ring and contact shoes. The electrodes can operate in a submerged-arc or brush-arc configuration, where the electrode is immersed in the slag or a short distance above the slag (Mc Dougall 2013). The electrode equipment is divided into an upper and a lower electrode assembly. The self-baking Söderberg electrode is made from lengths of steel casings that are added to the top of the electrode column and welded into place. Carbon electrode paste is added to the inside of these casings and is baked to form a solid tip in the region of the contact shoes. The working platform that surrounds the area where new electrode casings are added, is electrically isolated from the building and each electrode is isolated from the others to ensure the safety of the personnel who perform the electrode casing additions.

Jan 1, 2019

By R. T. Seaman

There are several hydrometallurgical alternative processing options under development for high enargite and arsenic containing copper concentrates ranging from biological, atmospheric, medium temperature oxidation to total oxidative leaching. The most developed of these options is the CESL process boasting pilot campaigns totaling more than 8760 hours of fully integrated continuous operation, as well as, over two thousand batch scale oxidation tests performed on dozens of concentrates for flowsheet development. This paper reports the observed deportment of arsenic under varying arsenic, iron and acid oxidation conditions; it also describes the impact of iron to arsenic ratios and residue recycle on overall arsenic behavior and its stability in residue. INTRODUCTION The CESL Hydrometallurgical Process (CESL) was originally developed to compete with smelting of clean chalcopyrite concentrates. High Treatment Charges and Refining Charges (TC/RCs) combined with premiums on London Metal Exchange (LME) grade copper from onsite refining made treatment of copper concentrates using CESL a viable option at the time. As world demand for copper increased and a subsidized Chinese refining market developed, smelting contracts became more favourable for the miner and focus was placed on modifying the CESL Hydrometallurgical Process to handle concentrates with elevated deleterious elements. Dozens of pilot campaigns processing concentrates containing elevated concentrations of uranium, fluoride, mercury and nickel all led to further developments of the CESL Hydrometallurgical Process. In 2016 a United States patent was granted for a novel modification of the CESL Hydrometallurgical Process for recovery of copper from arsenic-bearing and/or antimony-bearing copper sulphide concentrates, Henry Salomon de Friedberg (2016). To date, over 2000 bench scale tests along with five fully integrated closed loop pilot campaigns, totaling over a year of online operation time, have been conducted processing arsenic bearing copper concentrates. This paper summarizes the observed behavior of arsenic under varying autoclave and process conditions.

Jan 1, 2019

By Finley A. Campbell

"Nickel-copper sulphide deposits associated with basic rocks in the Quill Greek area and the White River area in the Yukon Territory have been studied and compared from the view-point of their general geology, structural geology, and the mineralogy of the ores. The relative amounts of the major constituents, magnesium, iron and calcium, and the minor constituents, nickel, cobalt and chromium have been determined spectrographically for two cross sections of the basic rocks at Quill Creek and one at White River. These data, along with petrologic and field evidence, were used to determine the sill and dyke-like character and nature of the basic intrusions. Loss on ignition is employed as a measure of the degree of serpentinization. The distribution determined shows that the serpentinization does not appear to have greatly influenced the inferred original distribution and lithophile associations of magnesium and nickel. The cobalt content may have been altered.The nickel content of the serpentinized peridotites ranges from an average of 0.36 per cent in one section to an average of 0.24 per cent in each of the other two sections studied. The cobalt averages 0.0038 per cent in the samples from the two Quill Creek sections and averages 0.0042 per cent at White River. These results have been compared with other available data.The sulphide ores are later than both the peridotite and gabbroic rocks and may be co-magmatic with them. There is no evidence in these areas to support an origin by lateral secretion; on the contrary, the alteration associated with the ores, the mineralogy and spatial relationship to basic and ultrabasic rocks, indicate the ores are derived from a basic magma."

Jan 1, 1960

By CIM Mineral Resource, Mineral Reserve Committee

The CIM Mineral Exploration Best Practice Guidelines (the Exploration Guidelines) have been prepared to assist professional geoscientists and engineers to conduct consistently high-quality work in order to maintain public confidence. The Exploration Guidelines are meant to assist professional geoscientists and exploration practitioners in planning, supervising, and executing exploration programs. In Canada, there are generally two types of public resource reporting: “Disclosure”, as defined by NI 43-101, is the reporting of technical information to the public and market participants for securities legislation purposes where a Qualified Person (QP) must be involved, and reporting of exploration information for governmental agencies to support obligations under laws including the Mining Acts of each of the Provinces and Territories. The Exploration Guidelines are also relevant where the results will not be publicly reported but are intended for internal company use. While this document is intended as guidance for work conducted or supervised by geoscientists in Canada, many of the practices described herein can be adapted to mineral exploration activities in other countries. The Exploration Guidelines are not intended to inhibit original thinking, or to prevent the application of new approaches that may develop into fundamental components of successful mineral exploration programs. Rather than provide prescriptive solutions to specific issues, they include general guidelines for current professional practice and to demonstrate and defend the merits of new methods. These guidelines do not preclude individuals and companies from developing more detailed guidelines specific to their own requirements. The initial version of the Exploration Guidelines was prepared by the Canadian Institute of Mining and Metallurgy and Petroleum (CIM) Exploration Best Practices Committee and adopted by CIM Council on August 20, 2000. On January 9, 2018, CIM Council formed a new committee, the Mineral Resources and Reserves Committee (CIM MRMR Committee) with a mandate to, among other things, update the Exploration Best Practice Guidelines. The mandate for the committee was accepted by CIM Council on March 2, 2018. The new document was adopted by the CIM Council on November 23, 2018.

Nov 23, 2018

By F. W. Crossland

Losses of metal are often traced to incorrect pH/ORP signals in flotation, leaching, extraction, electrolysis, and precipitation processes, aggravated by pressure changes. IC Controls, a Canadian mining sensor manufacturer, developed a new superior pH/ORP sensor that stops metal losses, reduces environmental footprint and contributes to sustainability. The cause of incorrect pH/ORP signal is rooted in the reference. Reference junctions are designed to allow diffusion of reference chloride ions into the process but also allow process ions to diffuse into the reference. This development is important to mines and hydrometallurgists where sulphide, cyanide, ammonia and other poisoning ions are present in the process. These ions react with reference electrolyte components causing the signal to change, drifting from the correct process value. With fluctuating process pressure, ion in migration dilutes the electrolyte producing similar signal drifts. If process ion in-diffusion could be stopped, the pH/ORP signal would be accurate. IC Controls new pH/ORP sensor stops process ion in-diffusion, and remains accurate over long periods. New processes using higher pressure and fluctuating pressurized reactors will greatly benefit from stable pH readings. Similar to IC Controls' proven model 642 Mining pH sensor, our new model 647 contributes to sustainability through reducing disposal costs from waste reagents, lost metal and fewer used sensors.

Jan 1, 2014

By Z. X. Cui, X. D. Ma, L. Contreras, X. Jiang

The bath smelting process is one of the key techniques applied in the current copper smelting production, which includes bottom-blown and side-blown furnaces differently from the direction of gas injection. Liquid matte and slag form the bath in the smelting furnace. To better understand the fluid dynamic of the bath and further optimise the operational efficiencies in the smelting furnace, physical simulation of the bath in the horizontal cylindrical reactor was investigated. The mixing behaviour and wave motion of the bath in the bottom-blown and side-blown furnaces have been studied systematically. The mixing time is reduced with increasing gas flowrate and height of the lower layer, while it increases significantly with increasing the height of the upper layer. The wave motion in the furnaces can be suppressed with the presence of the upper layer, but the bath with a lower density generates higher wave amplitude. Overall, in comparison to bottom-blown mixing, side-blown mixing shows better mixing efficiency and lower wave amplitude. In addition, the plume eye and splash phenomena occurred in the bottom-blown furnace have also been studied. INTRODUCTION The bath smelting process is one of the principal techniques used in the current copper making industry. The bath smelting techniques have some advantages of high smelting efficiencies, low capital costs, low energy consumptions and reduced dust generations. From the direction of gas injection, the bath smelting techniques can be classified into five general types: (1) top-submerged blown, e.g. Ausmelt and Isasmelt; (2) top-suspended blown, such as Mitsubishi smelting; (3) top direct-to-copper smelting, such as Outokumpu smelting; (4) submerged side-blown, such as Noranda and Teniente smelting; (5) bottom-blown, such as Dongying Fangyuan bottom-blown copper smelting furnace (Schlesinger et al., 2002; Zhao, Cui, & Wang, 2013; Perez-Tello et al., 2018). In many metallurgical processes involving bath smelting situations, the objectives of agitation are to accelerate the bath homogenization inside the bath which makes a significant contribution to process efficiency and product quality. Extensive mixing studies have been performed for ladle refining and tundish associated to steelmaking processes through water physical models. Mixing time is the parameter used to quantify the efficiency of mixing in the liquid bath and the first empirical equation predicting mixing time was proposed by Nakanishi, Fujii and Szekely (1975). Later on, more systematic studies have been carried out on ladle mixing and researchers realized that the geometry of the vessel could also have a significant impact on mixing (Khajaviand & Barati, 2010). However, the investigations using ladles which are vertical cylindrical vessels, cannot be directly used in the study of mixing behaviour in horizontal cylindrical reactors. Understanding the fluid dynamics inside horizontal cylindrical bath smelter is useful from the industrial perspective. Recently fluid dynamics of horizontal cylindrical smelter related to copper smelting have been studied by the authors’ group (Shui et al., 2015a, 2015b, 2018a; 2018b; Xu et al., 2018, 2019).

Jan 1, 2019

By C. Yanqui

"Discontinuum Mechanics is based on two foundations: the idealization of the internal structure of substances, and the principle of the arithmetic mean value. For a linear discontinuum, the methods of Crystallography are used to describe their structure, in which nodes stands for the position of the homologous points such as molecules, grains, or any other motif. The principle of the mean value states that the value of any discrete function at a node is equal to the arithmetic average of the values of this function at the neighboring nodes. This principle leads to an elliptical linear differential equation of the second order, with coefficients given by the statistical second moments of the Cartesian components of the metric vector. As long as those coefficients are components of a symmetric second-order tensor, there are three mutually perpendicular directions, in which the variances reach their extreme values and the covariances are zero, showing that the mean value principle transforms the discontinuum into a statistically equivalent orthotropic continuum.The application of Discontinuum Mechanics to linear rock masses is simple and direct. It is sufficient to define the motif as the plane of geological discontinuity, and the metric vector as the normal vector to this plane, whose magnitude is the spacing between two consecutive planes belonging to the same set of discontinuities. Furthermore, heterogeneities of rock masses can be also included in this description by substituting the plane of discontinuity by a zone of weakness. In this way, the magnitude of the normal vector results from the product of the spacing and the RQD or the RMR. In going further in this theory, at least three conclusions show up. First, in the evaluation of rock masses, it is necessary to determine the orientation, spacing, and RMR for each set of discontinuities. Second, the conventional method of finding the principal families from the contours of equal concentration of poles on the stereographic projection excluding the spacing does not have any physical meaning. Third, any problem of rock mechanics can be solved in a rigorous and reliable way by integrating the differential equation of the mean value."

Jan 1, 2015

By B. Jakovljevic, M. D. Soderstrom, T. McCallum, A. J. Quilodrán

Cytec has developed a new organophosphorus based solvent extraction (SX) reagent for rare earth separations. The new product, CYANEX® 572, has been formulated to allow efficient extraction while minimizing the strip acid requirements. The optimization of formulation strength is expected to significantly reduce the operating costs of these circuits. Modeling capabilities for CYANEX® 572 (similar to those used successfully in Cu and Co/Ni SX) have also been developed to aid in the design and optimization of the SX circuits. Simulations will be shown comparing CYANEX® 572 to a traditional rare earth extractant.

Jan 1, 2014

By W. L. Falconer

"IntroductionThe very recent emphasis on the importance of the northern portions of the Alberta basin as a prospective oil province has led the oil companies northward into new and undeveloped territory. Northern Alberta is a land of continuous forest, covering a plains-type topography. The plains are only occasionally broken by sharp, broad river valleys. Tributary streams head up quickly and very soon lose themselves in large undrained areas. It is these pseudo-swamps that cause most of the troubles and headaches of the oil explorer.The rivers have served as the main transportation arteries since people first ventured into this area. The bush is being pushed back, but the advance is slow and there is very little more than trappers' trails beyond a few miles from the Northern Alberta Railway lines and the recently built Grimshaw or McKenzie Highway. Indeed, bush and muskeg flank many miles of the railways and roads within as close a distance as fifty miles of Edmonton. Northern Alberta is pioneer country in the truest sense of the word, and our greatest problems derive from this fact. In all pioneer areas, the first requirement is the development of access roads, and before active oil exploraton can get down to the job at hand these roads and trails must be an accomplished fact. There are two factors in Northern Alberta which offer discouragement to the oil explorer: the first and greatest stumbling block is presented by the numerous muskegs, large and small; the second is the fact that road building uses up so much of reservation time. Of course, the second is aggravated by, and a direct result of, the first. So we come back to the main problem facing the development of the north - the muskegs."

Jan 1, 1950

By Palaniappan Chidambaram

Despite the advances in processing technologies, construction techniques, inspection methods, and materials, the number of process safety incidents are still increasing, and often the same types of incidents are being repeated. While regulators are enforcing stringent requirements in regards to safety management systems, process safety incident statistics reflect a failure in effective implementation. Upon closer look at the implementation of safety management systems, it becomes evident that the systems were not built on robust risk recognition. The risk-based implementation approach enables facilities to develop systems focused on managing specific risks and quickly gain momentum and confidence to take next steps towards implementing comprehensive systems. This paper will cover the importance of risk recognition and governance, risk based implementation and the role of Process Hazard Analysis in managing operational risks through the lifecycle.

Jan 1, 2014

By A. Welty, T. Garn, K. Lyon, B. Jakovljevic, R. S. Herbst, M. Greenhalgh, Cytec Solvay Group

"Industrial rare earth separation processes utilize PC88A, a phosphonic acid ligand, for solvent extraction separations. The separation factors of the individual rare earths, the equipment requirements, and chemical usage for these flowsheets are well characterized. Alternative ligands such as Cyanex® 572 and the associated flowsheets are being investigated at the pilot scale level to determine if significant enhancements to the current separation processes can be realized. These enhancements could be defined as higher separation factors, reduced stage requirements, or reduced chemical consumption. Any of these enhancements can significantly affect the costs associated with these challenging separation proccesses.A mid/heavy rare earth element (REE) separations flowsheet was developed and tested for each ligand in a 30 stage mixer-settler circuit to compare the separation performance of PC88A and Cyanex® 572. The ligand-metal complex strength of Cyanex® 572 provides efficient extraction of REE while significantly reducing the strip acid requirements. Reductions in chemical consumption have a significant impact on process economics for REE separations. Partitioning results summarized Table 1 indicate that Cyanex® 572 offers the same separation performance as PC88A while reducing acid consumption by 30% in the strip section for the mid/heavy REE separation."

Jan 1, 2016

By H. Gharahbagheri, S. Shafiei Zadeh, H. Hassan Nejad

Waste Electrical and Electronic Equipment (WEEE) is one of the fastest growing types of solid waste in the world, and often contains precious metals, especially gold. Gold processing and recovery from secondary materials, especially WEEE, have been under investigation for more than a decade now; however, a comprehensive review that illuminates the future path is missing in the literature. The aim of this short paper is to discuss the recent advances in gold processing and recovery from secondary electronic materials and why it has not yet become practical. The role of pyrometallurgical and hydrometallurgical methods, as well as their advantages and disadvantages will be discussed; however, the focus will be on Biosorption and recent advances.

Jan 1, 2014

By Norman A. Grant

"Location and Transportation FacilitiesTHE BEAVERLODGE area of North Saskatchewan is on the north side of lake Athabasca, 500 air miles northeast of Edmonton.The main Eldorado operation and townsite are on the north •side of Beaverlodge lake, which is immediately north of lake Athabasca and is separated from it by only a mile long portage at Lodge bay. The once famous town of Goldfields. Saskatchewan, and the Box property of the Consolidated Mining and Smelting Company of Canada, Limited, are located on lake Athabasca nine mines from Beaverlodge townsite.Previously, all Eldorado freight was delivered by barge at the Lodge Bay portage, hauled across the portage, and across Beaverlodge lake by small Northern Transportation Company barges, which involved many handlings.In 1952 the port of 'Bushell' was established at Black bay. This is a particularly snug harbour, well protected from the main body of the lake and with good foundations for docking facilities. A Butler building, 300 ft. by 60 ft., and tank farms provide storage at the port. A •road from Bushell to the main Beaverlodge operation, a distance of twelve miles through rugged terrain, was built by the Saskatchewan Government. The cost was shared by the Saskatchewan Government, the Federal Government, and Eldorado and other mining companies.Along this road are located the properties of several enterprising mining companies and near the midpoint lies the ambitious budding town of Uranium. This road has made portaging unnecessary and palletized freight loaded at Waterways, Alta., is now loaded directly on trucks at Bushell and delivered to the point of consumption."

Jan 1, 1953

By J E. McMynn

The development of the Granduc mine presents a number of problems which are peculiar to its location and surrounding terrain. Because the development tunnels portal onto an area which is covered by an extensive glacier, and the mountain-side is subjected to dangerous snow slides, it was decided to construct an underground powerhouse to supply the necessary electric power and compressed air. This paper deals with the special problems inherent in the design and -construction of an underground plant. It involves the installation of diesel-electric generating equipment having an aggregate capacity of 1,050 kw.,and of air compressors with a total capacity of 2,400 cfm. Items dis-cussed include the selection of equipment to meet site conditions, the ventilation and cooling of the underground room, and the protection of personnel and equipment from explosions and fire. A short discussion on the automatic supervisory and alarm installation is also included. THE Granduc mine is located 135 miles north of Prince Rupert and 25 miles north of Stew-art. This seems quite accessible, mileage-wise, but, due to mountains,

Jan 1, 1963

By A. Luckita, A. Samtani, R. Barus, J. R. Donald, J. Syarifuddin

In conventional Rotary Kiln-Electric Furnace (RK-EF) laterite nickel processing, management of dust continues to be problematic. A more efficient processing of dust represents an opportunity for energy efficiency, increased production, and productivity. PT International Nickel Indonesia (PTI), together with Vale Base Metals Technology Development (VBMTD), has successfully developed and implemented a novel flowsheet enhancement that capitalizes on these opportunities. In the novel flowsheet, the dust recycle stream is moved forward in the RK-EF laterite nickel smelting process. The dust is injected into the kiln's main burner, as opposed to being recycled to the dryers. A similar treatment of dust is commonly practiced in the cement industry; however, application to nickel smelters has not been fully developed to date. This paper describes this dust insufflation technology, the process through which it was developed for laterite nickel processing, and summarizes the lessons learned. A key conclusion is that successful new technology development requires a multi-disciplinary team involving members from research and development, study management, engineering consulting firms, project implementation management, process technology and operations.

Jan 1, 2011

By A. Fahr, T. Byczkowski, M. Genest, C. Mandache

"Layered aluminum structures assembled with rivets are often found in aircraft fuselage. These structures are exposed to various mechanical loads and a range of environmental conditions that contribute to their ""aging"". The rivet holes are the source of stress concentrations and the location of crack nucleation and growth. Detection and sizing of second and third layer cracks under fasteners represent a major challenge for non-destructive evaluation (NDE) technicians. Electromagnetic methods are currently the most feasible NDE techniques that are capable of successfully inspecting such structures. However, different probe lift-offs, due to protruding rivets and paint coatings, or interlayer separations, due to sealant or air gaps, pose difficulties in detecting and sizing cracks. In addition, the use of conventional eddy current technique is limited due to the inverse relationship between the probe spatial resolution and its field penetrability. In this paper, we present an alternative approach that overcomes the previously mentioned shortcomings by using pulsed eddy current excitation and magnetoresistive sensor pick-up. Various signal manipulations are employed for defect detection and quantification."

Jan 1, 2006

By W. Beres, Li. J.

The finite element method (FEM) has been applied to investigate the stress fields and deformation of a TiN/Ti-6A1-4V coating/substrate system subjected to nanoindentation. MSC Patran and MSC Marc were used to prepare the three-dimensional finite element models and to perform the simulations of the Vickers nanoindentation experiments. Pure silicon and TiN/Ti-6A1-4V coating/substrate system were analyzed. The properties of the materials were assumed to be homogeneous and isotropic with a linear hardening behavior. The reverse method was used to extract material properties, such as the yield stress and strain hardening coefficient, from the numerical results by comparing the simulated indentation load vs. penetration depth (P-h) curves with those obtained experimentally. Both non-linear elastic and non-linear elastic-plastic analyses were carried out for the coating/substrate system. The results are given for four different coating thicknesses.

Jan 1, 2004

By X. -G. Chen, J. Qin, K. Liu, D. Racine

"Understanding the thermo-mechanical fatigue (TMF) behavior of materials plays a significant role in the safety design of critical components used in aerospace and automotive industries, such as engine blocks and cylinder heads, which undergo the cyclic change of temperature and stress. However, the cyclic changes of temperature, stress and strain make it difficult using the traditional testing methods to accurately simulate the TMF process. In the present work, the Gleeble® 3800 system was successfully applied to develop a reliable procedure to measure the TMF behavior of aluminum alloys. The modified setup together with the new designed program allows the Gleeble system to precisely simulate the cyclic profiles of temperature and mechanical strain. The novel procedure includes the calibration and verification of the TMF setup to ensure the test validity with Young’s modulus measurement, multi-cycle measurement of the thermal strain and zero stress adjustment followed by online monitoring the TMF cycles. The results of the TMF testing of an AA6061 alloy under cyclic temperatures (60–300°C) and various strain amplitudes (0.2–0.6%) were demonstrated. Its TMF behavior was characterized by the typical hysteresis loops and cyclic stress-strain response.INTRODUCTION The thermo-mechanical fatigue (TMF) behaviour becomes increasing important to evaluate the elevated-temperature properties of materials used as the critical components in automotive and aerospace industries, such as the gas turbines (Hu, Shi & Yang, 2016; Moverare, 2007; Segersäll et al., 2015) and engine blocks (Grieb, Christ & Plege, 2010; Javidani & Larouche, 2014). During the cycles of start-up and shutdown of the engines, these components undergo a complex change of loading. Meanwhile, a dramatic temperature gradient exists on the components due to the cooling system. Therefore, the cyclic changes of load and temperature can give rise to the TMF and may limit the use life of such components (Hu, Shi & Yang, 2016; Javidani & Larouche, 2014; Moverare, 2007). Hence, performing the TMF tests to precisely simulate the cyclic changes of load and temperature to understand the TMF behaviours of materials is playing a significant role in the safety design of these components. For TMF tests, two principal types of cycles are generally employed, including the in-phase (IP) cycle where the load and temperature are at the same phase (i.e. maximum load at highest temperature) and out-of-phase (OP) cycle where the maximum load is applied at minimum temperature (Kliemt, 2012; Miller, 2014). The most significant damage mechanisms in engine components are reported to be OP TMF cycles (Javidani & Larouche, 2014; Kliemt, 2012)."

Jan 1, 2018

By N. Moelans, I. Bellemans, K. Verbeken

In this work, we present a phase field model to simulate the facetted crystallization of Fe3O4 in a quaternary FeO-Fe2O3-Cu2O-SiO2 melt under different partial pressures of oxygen. An important focus in creating more realistic phase field models is the incorporation of the thermodynamic driving forces in multicomponent multiphase-field models by coupling to thermodynamic databases. The diffusion of FeO, Fe2O3 and Cu2O is considered. The ratio of FeO/Fe2O3 at the upper boundary is in equilibrium with the oxygen fugacity of the atmosphere, while conserving Fe. Two-dimensional simulations are performed with different varying oxygen fugacity in the atmosphere. For the considered composition range, the growth velocities of the spinel crystals increase with decreasing oxygen fugacity. INTRODUCTION Crystallization of silicate melts has its applications in geology, pyrometallurgy and glass making. In pyrometallurgy, the solidification of slags influences the freeze lining behaviour (Campforts et al., 2007) and the cooling of slag after tapping (Durinck, Jones, Blanpain, & Wollants, 2008). Modeling of silicate melt crystallization is frequently done on the macroscopic level, using thermodynamic equilibrium calculations to determine the fractions of all phases as a function of temperature. The Factsage software and database package (Bale et al., 2016, 2009, 2002) already proved its usefulness in pyrometallurgical applications, for example to model the phase mixture after solidification of a stainless steel slag (Durinck et al., 2008). Crystallization of phases typically results in complex morphologies on the mesoscale, e.g. dendrites or facetted growth. On this mesoscale, the phase field concept has proved to be a very powerful tool (Moelans, Blanpain, & Wollants, 2008) for modeling crystallizing microstructures, because it can treat arbitrarily complex interface shapes with minimal mathematical complexity. In contrast to macroscopic models, the diffusion profiles and crystallization kinetics can be described as well as the morphology of individual crystals. First, Kobayashi (Kobayashi, 1993) simulated a growing dendrite in a pure undercooled metallic liquid. Then, Warren and Boettinger (1995) simulated a dendrite in an isothermal system considering a binary alloy. The extension to multi-phase systems was done by Steinbach et al. (1996). This was further extended by Tiaden, Nestler, Diepers, and Steinbach (1998) to a framework with coupled diffusion and phase field equations in multi-component systems.

Jan 1, 2019