The Kalplats platinum group metal deposit is located in the Northwestern Province of South Africa, 80 km southwest of Mafikeng, in the Stella Layered Intrusion. The Stella Layered Intrusion intruded into the Kraaipan Greenstone Belt and is dated at 3.03 billion years. The Kraaipan Greenstone Belt is host to the 80 000 ounce per annum Kalgold Gold Mine. Platinum Group Element mineralized layers in the Stella Layered Intrusion are interpreted to occur in the overturned western limb of folds, formed by an eastward vergent compressional event. Three major reefs have been identified, namely the Lower Grade (LG) reef, the Mid Reef and the Main Reef. High grade reefs occur within these three. The average Pt:Pd ratio of the Main Reef is 1:1. Highest total precious metals content is concentrated in the Upper Main and Lower Main Reefs and the average grade for these two reefs is 4g/t. Open pit mining is suggested. The total inferred precious metals resource equates to 84Mt at an average grade of 1.4 g/t Pt+Pd+Au, for 3.9million ounces. Platinum, palladium and gold occur as fine grains. Maximum recoveries of approximately 72% are possible, from sulphide ore, using a twostage mill-float circuit. The estimated reserve (non-JORC compliant) is 26 Mt at an average grade of 2.01g/t Pt+Pd+Au, for 1.68 million ounces. A financial evaluation was done on the viability of the Kalplats deposit, using a discounted cash flow model. Future projections used were a R/$ exchange rate of R6-50 to the dollar and long-term metals prices of US$ 800/oz Pt, US$ 200/oz Pd and US$ 400/oz Au. The result of the discounted cash flow model was negative and indicated no return on capital and a negative Nett Present Value (NPV) of –R206 million at a discount of 13%. Factors impacting negatively on the viability of the project, include grade, metallurgical recovery, smelter fees, government royalties, metals prices and the Rand-US$ exchange rate. / Dissertation (MSc (Geology))--University of Pretoria, 2008. / Geology / unrestricted

As a result of the intense air-water interaction in the spray nozzle, air-mist spray is one of the most promising technologies for attaining high heat transfer. CFD simulations and multivariable linear regression were used in the first part of this study to analyze the air-mist spray produced by a flat-fan atomizer and to predict the heat transfer coefficient using the casting operating conditions such as air pressure, water flow rate, cast speed and standoff distance. For the air-mist spray cooling simulation, a four-step simulation method was utilized to capture the turbulent flow and mixing of the two fluids in the nozzle, as well as the generation, transport, and heat transfer of droplets. Analysis of the casting parameters showed that an increase in air pressure results in efficient atomization, increases the kinetic energy of the droplets and produces smaller droplet size thus, the cooling of the slab increases significantly. Also, a decrease in water flow rate, standoff distance and casting speed would result in more efficient cooling of the steel slab. The second part of the study investigated the solidification of steel in the secondary cooling region. Caster geometry and casting parameters were studied to evaluate their impact on the solidification of steel. The parameters studied include roll gap, roll diameter, casting speed and superheat. It was found that a smaller ratio of roll gap to roll diameter is more efficient for adequate solidification of steel without any defect. Casting speed was found to have a significant effect on the solidification of steel while superheat was found to be insignificant in the secondary zone solidification. The result from the air-mist spray cooling was integrated into the solidification model to investigate the solidification of steel in the entire caster and predict the surface temperature, shell growth and metallurgical length. To replicate real casting process, temperature dependent material properties of the steel were evaluated using a thermodynamic software, JMatPro. The air-mist spray model was majorly investigated using ANSYS Fluent 2020R1 CFD tool while the solidification of steel was studied using STARCCM+ CFD software. Using the findings from this study, continuous casting processes and optimization can be improved.

The goal of this thesis is to verify influence of conditions of metallurgical treatment, used foundry technology and conditions of solidification on electrical conductivity of pure copper castings. The experiment part observe differenec between alloy melting under normal pressure and in a vacuum and betwwen casting provided with chill, insulation and natural enviroment of mould.

The prediction of material behavior and its microstructural evolution during high velocity impacts has been investigated for decades. The application of this topic can be observed in various engineering applications such as the cold spray process. Cold spray (CS) is an additive manufacturing method in which solid particles are accelerated using a low temperature supersonic inert gas flow, prior to their impact onto a substrate and adhesion/consolidation. In this process, unlike other thermal spray processes, the particles are kept well below their melting point prior to impact. This allows the CS process to be used for the manufacturing of high quality, specialized products at a low energy input. In CS, the deformation and bonding processes happen in a very short time (less than 100 ns). With the current technology, in-situ investigation is almost impossible. In this situation, numerical modeling methods are the best alternative to study the deposition process. There are several factors influencing the particle deposition, such as particle/substrate material properties, particle size, material temperature, particle velocity and so on, but it has been shown that the particle impact velocity has the major role during the deposition process. In fact, despite the type of bonding, i.e., mechanical or chemical, particle is sticking to the substrate after experiencing severe plastic deformation that occurs upon the impact at high velocities. Therefore, in order to develop the understating of the CS process, investigating the deformation behavior of material during high velocity impacts, and also bonding mechanisms involved during particle deposition must be investigated. III Although numerous studies have been done to explore the mechanisms occurring during particle deposition, the details of this process are still unclear. Therefore, the purpose of this research is to study the fundamental aspects of material behavior during the deformation and deposition processes with the aim of improving the understating of the CS process. Two different numerical approaches will be used to achieve the objective of the study, i.e., Finite Element Method (FEM) and Molecular Dynamics (MD) method. FEM will be used to study the metallic bonding occurring between the particle and the substrate. A physically based model to predict this phenomenon will be implemented into ABAQUS/Explicit FEM software. MD simulations will be performed to investigate the microstructure evolution during high velocity impacts. In order to characterize the deformation behavior of materials at a fundamental level, analysis will be focused on the basic mechanisms of plasticity and hardening in metals, i.e., the multiplication, glide and locking of dislocations, and also solid-state amorphization that happens at high strain rate deformations.

<p> Around 98% of the crude steel produced in the United States goes through the CC process, in which a water-cooled mold is used to solidify molten steel using water sprays to create semifinished slabs or billets. The quality of both the exterior and inside of the slab is directly related to the rate at which it is cooled, making secondary cooling a difficult process. The heat must be removed efficiently without causing the slab to crack or deform in any way. Low grade steel is produced because of inadequate spray cooling and solidification, which leads to flaws like cracking and breakout. Real-time online dynamic casting control systems are becoming increasingly popular in continuous casting as a means to increase yield and energy efficiency. These systems are built to reliably produce high-quality steel products via real-time temperature measurements and dynamic adjustment of the spray cooling rate. For real-time heat transfer and solidification calculations in the field, the key challenge is determining an accurate Heat Transfer Coefficient (HTC) for the steel product's surface. The correlations for predicting the spray cooling rate empirically have been developed with great care. Nevertheless, these correlations are only valid under specific application circumstances. Building it takes a significant amount of time and effort, and there is no assurance that the correlation will continue to accurately predict HTC even if the development process is modified in any way. An in-depth investigation into the heat transfer mechanisms that take place during the secondary cooling step of continuous steel casting is required in order to achieve control and optimization goals for this step. The non-optimized solidification process also contributes to the formation of inhomogeneous steel properties. The project required the application of computational fluid dynamics modeling techniques so that the casting process could be regulated and improved upon. Simulation of droplet formation, droplet transport, and impingement heat transfer during secondary cooling with an air-mist nozzle in a 3D computational fluid dynamics (CFD) model is going to be done in this study with the intention of generating a multivariable correlation that can accurately predict the lumped HTC under any casting condition. This will be accomplished by using the model. It modeled the solidification of the whole continuous caster by taking into consideration the impacts of roll gap, roll diameter, casting speed, and superheat in order to estimate the metallurgical length and slab temperature. This was done in order to calculate the metallurgical length </p>

The ladle metallurgical furnace (LMF) is a very flexible and common unit operation found in most steelmaking melt shops, and enables the adjustment and fine-tuning of molten steel's composition and temperature prior to casting. Despite the importance of ladle metallurgy to the overall steel making process very little has been achieved in the way of advanced ladle control. Limited sensors are available to monitor heat progress during refining and current control methods involve manual procedures. This thesis represents part of an ongoing study on the modelling of a full-scale LMF in real-time with the forward goal of improved control and optimization. The first part of this thesis details a vision-based sensor for analyzing ladle eye dynamics online using a multivariate image analysis (MIA) technique based on principal component analysis (PCA). Predictive capabilities of the developed model are demonstrated using previously published cold model data over a wide range of operating variables. Further, preliminary work has confirmed the ability of the sensor for potential use in an industrial setting. The second part of this study concerns the development of metallurgical models for assessing the state of a ladle metallurgical furnace. Specifically, a multi-component kinetic model in combination with developed slag and steel thermodynamic solution models were used to quantitatively describe the kinetics of slag-metal reactions within 41 industrially sampled heats at ArcelorMittal Dofasco's LMF#2. Metal phase mass transfer coefficients for all elements in steel were assumed to follow the empirical relation derived from measured sulphur contents, while slag phase mass transfer coefficients were calculated by fitting the ratio of k^Mm/ k^MxOysl to the experimental results. On the basis of the fitted results, slag phase mass transfer coefficient correlations were evaluated using linear regression. Computed results from the model using these slag phase mass transfer coefficient correlations were found to be consistent with the experimental data. In regard to the developed thermodynamic solution models, original contributions to the modified interaction parameter formalism and cell model are presented. As process model predictions are invariably uncertain, the final part of this work involves the use of a stochastic model (extended Kalman filter) to account for process disturbances, model-mismatch and other sources of uncertainty that may result in significant error propagation causing poor process control and plant economics. Several case studies were performed to illustrate the effectiveness of the extended Kalman filter and its application to optimal sensor selection was introduced. / Thesis / Doctor of Philosophy (PhD)

The localised corrosion behaviour of various grades of Austenitic Stainless Steels has been demonstrated by optical and electron microscopy. The effect of sensitisation upon subsequent corrosive attack has been investigated. A theoretical model based upon thermodynamic and kinetic considerations has been proposed to account for the observed experimental results. / Thesis / Master of Engineering (ME)

Процедура банкротства предприятий неразрывно связана с экономикой страны с самого начала ее становления. Нестабильность экономики негативно отражается на деятельности предприятий и может привести к необратимым последствиям. Оценка вероятности банкротства – это количественный показатель, характеризующий степень вероятности банкротства в определенном случае. Проведение мероприятий, направленных на диагностику финансового состояния является неотделимой частью финансово-хозяйственной деятельности предприятия, так как зачастую несостоятельность наступает в результате внутреннего финансового кризиса предприятия. Таким образом, была сформулирована следующая цель исследования: разработать методический инструментарий оценки вероятности банкротства металлургических предприятий, учитывающий отраслевую специфику деятельности. Объектом исследования являются российские предприятия металлургической отрасли. Предметом исследования является оценка вероятности банкротства металлургических предприятий Российской Федерации. / The bankruptcy procedure of enterprises is inextricably linked with the country's economy from the very beginning of its formation. The instability of the economy negatively affects the activities of enterprises and can lead to irreversible consequences. Assessment of the probability of bankruptcy is a quantitative indicator that characterizes the degree of probability of bankruptcy in a certain case. Carrying out measures aimed at diagnosing the financial condition is an inseparable part of the financial and economic activities of the enterprise, since often insolvency occurs as a result of the internal financial crisis of the enterprise. Thus, the following research objective was formulated: to develop methodological tools for assessing the probability of bankruptcy of metallurgical enterprises, taking into account the industry specifics of the activity. The object of the study is the Russian enterprises of the metallurgical industry. The subject of the study is the assessment of the probability of bankruptcy of metallurgical enterprises of the Russian Federation.

ВКР (магистерская диссертация) состоит из введения, трех глав, заключения, библиографического списка, включающего 72 наименования, 2 приложения. Работа включает 7 таблиц и 29 рисунков. Общий объем ВКР (магистерской диссертации) – 93 страницы. Цель исследования – разработка методического подхода к управлению портфелем заказов на металлургическом предприятии. Научная новизна исследования состоит в том, что разработан методический подход к управлению портфелем заказов на металлургическом предприятии, отличающийся от ранее применяемых разработкой и внедрением в процесс планирования производственной деятельности информационно-экономического инструментария позволяющего: формировать совокупность внешних заказов, которыми располагает предприятие на текущий момент времени; оценивать загруженность производственных мощностей металлургического предприятия; на основе проведенной оценки оптимизировать распределение заказов между металлургическими предприятиями; определять потенциальные сроки изготовления новых заказов, что развивает методические подходы к управлению портфелем заказов на металлургическом предприятии для выполнения заказов точно в срок. Практическая значимость исследования заключается в том, что предлагаемый в работе методический инструментарий для управления портфелем заказов направлен на повышение эффективности производственной деятельности металлургического предприятия. Основные теоретические и методические положения, описанные в работе, позволяют осуществить совершенствование процесса формирования портфеля заказов с одновременным повышением эффективности производственной системы в целом. Эффективность рекомендаций – предложенные автором рекомендации позволят определять текущую загрузку производственной мощности металлургического предприятия, согласовывать с заказчиком выполнимые сроки поставки продукции по заказам и улучшить показатель своевременности доставки продукции потребителю, что положительно скажется на имидже компании. / WRC (master's thesis) consists of an introduction, three chapters, a conclusion, a bibliographic list, including 72 titles, 2 appendices. The work includes 7 tables and 29 figures. The total volume of the WRC (master's thesis) is 93 pages. The purpose of the study is to develop a methodological approach to managing a portfolio of orders at a metallurgical enterprise. The scientific novelty of the study lies in the fact that a methodological approach to managing a portfolio of orders at a metallurgical enterprise has been developed, which differs from those previously used by the development and implementation of information and economic tools in the planning process of production activities that allow: to form a set of external orders that the enterprise has at the current time; assess the workload of the production capacities of a metallurgical enterprise; on the basis of the assessment, optimize the distribution of orders between metallurgical enterprises; to determine the potential terms of production of new orders, which develops methodological approaches to managing the portfolio of orders at a metallurgical enterprise to fulfill orders just in time. The practical significance of the study lies in the fact that the methodological tools proposed in the work for managing a portfolio of orders are aimed at improving the efficiency of the production activities of a metallurgical enterprise. The main theoretical and methodological provisions described in the work allow to improve the process of forming a portfolio of orders while increasing the efficiency of the production system as a whole. Efficiency of recommendations - the recommendations proposed by the author will allow determining the current loading of the production capacity of a metallurgical enterprise, agreeing with the customer on feasible delivery times for products on orders and improving the indicator of timely delivery of products to the consumer, which will positively affect the company's image.

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