The ladle furnace process is an important process in the steel manufacturing industry. The purpose of this process is to optimize the composition of the elements in the melt as well as to homogenize the temperature in the liquid. It is common practice to model this process using smaller water models. In order to accurately scale these models a variety of criteria and scaling factors are needed. The central phenomenon which all else is derived from is the two-phase gas plume dominating the fluid flows. The plume, and its dependant parameters are difficult to define. Which ones ought to be used and how to use them has not been standardized. Concerns have been raised whether the most common method of scaling is even applicable in ladle metallurgy. This report gives an account for studies concerning these variables and their effect on the subject. The objective of this report is to highlight ways to improve these simulations with respect to debated parameters. The conclusion of this study points out the reasons for why these variables may be of importance for the modeling of the ladle furnace process. It also specifically mentions future work that should be conducted in order to provide deeper knowledge of thedifferent parameters affecting the method of modeling. / Skänkmetallurgin är en viktigt process inom stålindustrin. Syftet med denna process är att optimera den kemiska sammansättningen i smältan och att homogenisera temperaturen i vätskan. Det är vanligt att modelera denna process med hjälp av vattenmodeller. För att träffsäkert skala dessa modeller krävs en mängd kriterier och skal-faktorer. Det mest centrala fenomenet, utifrån vilket allt annat kan härledas, är två-fas gasplymen som dominerar flödena i skänken. Plymen och dess beroende parametrar är svåra att definera. Vilka som bör användas och hur de används har inte standardiserats. Oro har väckts över om den vanligaste skalningsmetoden ens går att använda i skänkmetallurgi. Denna rapport redogör för studier rörande dessa variabler och deras påverkan på ämnet. Syftet med denna rapport är att belysa olika tillvägagångssätt till att förbättra dessa simulationer med hänsyn till debaterade parametrar. Slutsatsen för denna studie lyfter fram anledningarna till varför dessa variabler är av vikt för modellering för skänkmetallurgin. Även framtida arbete som bör utföras föratt ge djupare förståelse för de olika parametrarna belyses.

The muffle furnace main purpose is to anneal the rough sponge iron powder transported through it, which is done by burning natural gas. Heat is absorbed by the muffle and is transferred to the bed of sponge iron powder. In order to reduce the consumptions of fossil fuel, some companies of the industry aims to exchange the natural gas in their muffle furnace’s burners to syngas, produced from biomass. This will however affect the performance of the furnace in the heating aspect. For this work, it is assumed that the effect will be negative. Thus the aim of this study is to investigate how to compensate the loss of effect from the burners, by examining which other parameters have influence on the furnace heating performance of the sponge iron powder transported through the furnace. The investigation is executed by simulating a 1 meter of the furnace in COMSOL multiphysics for 10 min, not including the combustion chambers. The investigated parameters are the packing degree of the powder, surface emissivity of the muffle, process gas velocity, conveyor belt velocity and the heat transfer rate coefficient to muffle from the combustion chambers. Alas, the process gas velocity and conveyor belt velocity only have minor influence on the final result, according to this simulation. However, the simulation exhibited that the surface emissivity of the muffle and the packing degree of the powder has great impact on the heating of the powder and could compensate some of the lost effect from the burners. This could be obtained by using an unpolished and oxidized muffle surface, and use densely packed powder sample.

In the steel industry, slag foaming plays a crucial role in many steel processes, given its positive impact on the thermal efficiency of the furnace and its life span. However, excessive foaming causes an overflow in the converter known as “slopping”. Slopping hinders the effectiveness of the processes, especially with the complex and unpredictable foaming rate. This problem occurs mainly in the BOS-processes and after melt tapping to the ladle furnace. The goal of this study is to test and relate a new foaming control system, by blowing a gas (nitrogen or argon) on the surface of the melt to suppress the foam. Firstly, the foaming index of the provided industrial heats for a general LD converter (21 heats) and Outokumpu’s ladle furnace (31 heats) were calculated to find which heat is most likely to slop. Then, a series of experiments were performed to investigate the new foam controlling system’s reliability using a cold model. The results demonstrated that blowing argon instead of nitrogen from the top nozzle suppresses the foam more effectively, which can be attributed to its higher density. Additionally, the optimal argon flow rate required to suppress the foam in worst-case slopping scenarios in the LD converter and the ladle furnace were 874 and 221 m3/min respectively. The provided data further supports the efficacy of this slopping prevention technique, in theoretical and practical aspects. / I stålindustrin spelar slaggskumning en avgörande roll i många stålprocesser, med tanke på dess positiva inverkan på ugnens termiska effektivitet och dess livslängd. Överdriven skumning orsakar emellertid ett överflöde i konvertern som kallas "utkok". Utkok hindrar processernas effektivitet, särskilt med den komplexa och oförutsägbara skumningshastigheten. Detta problem uppstår främst i BOS-processerna och efter tappning till skänkugnen. Målet med denna studie är att testa ett nytt kontrollsystem genom att blåsa en gas (kväve eller argon) på smältytan för att slå sönder skummet. Först beräknades skumindexet för de tillhandahållna industriella chargerna för en allmän LD (21 charger) och Avestas skänk (31 charger) för att hitta vilken charge som har störst risk för utkok. Därefter utfördes en serie experiment för att undersöka det nya skumstyrsystemets tillförlitlighet med hjälp av en kall modell. Resultaten visade att blåsning av argon istället för kväve från det övre munstycket undertrycker skummet mer effektivt, vilket kan hänföras till dess högre densitet. Dessutom var den optimala argonflödeshastigheten som krävdes för att undertrycka skummet i värsta fallet i LD och skänkanläggningen 871 respektive 221 m3/min. De tillhandahållna uppgifterna stöder ytterligare effekten av denna förebyggande teknik, i teoretiska och praktiska aspekter.

Increasing awareness of sustainability in the concrete industry forces structural design and executionto focus on avoiding costly and unpredictable maintenance action, instead paying higher attention todamage prevention by direct actions on early stages of production. One of such approaches, whichdeals with the problem of freezing and thawing deterioration, is intentional air bubble introductionto the concrete mix. However, the mechanism of air entrainment in concrete can be negativelyaffected on different stages of production by many factors including cement type, admixture dosage,casting conditions or mixing procedure. Therefore, reliable tools for the end-product evaluationought to be considered. The experimental study, presented in this work, focuses on understandingthe blast furnace slag (BFS) influence as well as admixtures’ dosage effect on pore structure ofhardened concrete. Three types of cement were evaluated, including ordinary portland cement(OPC) and two types of CEM III cements with different BFS percentage. The optimal amountsof air entraining agent (AEA) and super plasticizer (SP) were chosen and later reduced in orderto evaluate their impact on total air content, spacing factor and specific surface of the air voids.The main method chosen for this evaluation was the use of an office flat-bed scanner to acquireimages and application of BubbleCounter software for the analysis of the air void structure. Thisapproach is based on linear traverse method and requires special surface treatment for contrastenhancement. Specimens for the analysis were cut from hardened concrete cubes and polishedto achieve a flat surface. The samples were later treated with black ink and zinc oxide paste toachieve a clear contrast between white voids and black paste/aggregate area. In order to estimatethe accuracy of this method, more conventional tools such as pressurised gauge method and air voidanalyser were applied for comparison. Resulted mixtures showed significant differences in air voidproperties between OPC and BFS containing concrete, with the latter being less affected by AEAdosage reduction. Changes in spacing factor and specific surface were also registered; however,their deterioration did not follow the same pattern as that of total air content. No significantdeviation between the two cements containing BFS was observed. An interesting effect of the usedpolycarboxylate ether SP on the AEA reactivity was registered, showing deterioration of air voidproperties with the decrease of plasticizer amount. Comparison of the results from different air voidanalysis methods, suggested an overall agreement on the measured air void system changes due tochanging the AEA content. However, the BubbleCounter software tended to slightly overestimatethe material’s resistance to freeze and thaw phenomenon, giving the most optimistic values inspacing factor and specific surface of air voids. / Betongindustrins ökande medvetenhet om hållbarhet leder till att man inom dimensionering ochutförande fokuserar mot att undvika kostnadskrävande och oförutsedda underhållsåtgärder ochistället lägga större vikt på att förebygga skador i produktionens tidiga skeden. En av dessaåtgärder, som hanterar problemet frostnedbrytning, är en medveten inblandning av luftbubblor ibetongen. Mekanismen för att skapa luftporssystemet kan emellertid bli negativt påverkad underolika skeden av produktionen av många faktorer såsom cementtyp, tillsatsmedelsdos, gjutvillkoroch blandningsordning. Därför behöver man reflektera över pålitliga verktyg för utvärderingenav slutprodukten. Den experimentella studien, som presenteras i detta arbete, fokuserar motförståelse hur slagg och tillsatsmedelsdos påverkar den hårdnade betongens luftporssystem. Tretyper av cement utvärderades, dels ett normalt portlandcement, dels två typer av CEM III-cementmed olika andelar av slagg. Optimala mängder av luftporbildare och flyttillsatsmedel valdesmen reducerades senare för att undersöka deras inverkan på totalt luftinnehåll samt luftporernasavståndsfaktor och specifika yta. Den huvudsakliga metoden som valdes för denna utvärderingvar en flatbäddsscanner (kontorsmodell) för att ta bilder och användningen av en programvaravid namn BubbleCounter för att analysera luftporssystemet. Detta tillvägagångssätt baseras påanalys av tvärgående linjer och kräver en speciell behandling av ytan för att åstadkomma kontraster.Provkroppar för analysen sågades ut ur hårdnade betongkuber och polerades för att erhålla en jämnyta. Provkropparna var senare behandlade med svart bläck och zinkoxidpasta för att åstadkomma entydlig kontrast mellan de vita porerna och den svarta ytan av cementpasta och ballast. För att studeranoggrannheten hos denna metod användes som jämförelse även mer konventionella metoder sommätningar med trycksatta givare och luftporsanalys. De framtagna blandningarna visade signifikantaskillnader i luftporernas egenskaper mellan betong med normalt portlandcement och betong medslaggcement, där den senare påverkades i mindre grad av reduktioner i dosen luftporbildare.Förändringar I avståndsfaktor och specifik yta noterades också men försämringen följde inte sammamönster som den för totala luftinnehållet. Ingen signifikant skillnad mellan de två cementeninnehållande slagg kunde observeras. En intressant inverkan av det använda polykarboxylateterbaseradeflyttillsatsmedlet på luftporbildarens reaktivitet noterades. Den visade en försämringav luftporernas egenskaper vid en reduktion av mängden flyttillsatsmedel. En jämförelse avresultaten från de olika metoderna för luftporsanalys indikerade en övergripande överensstämmelsegällande de uppmätta luftporssystemens förändring p.g.a. förändringar i mängden luftporbildare.Programvaran BubbleCounter tenderade emellertid att något överskatta materialets motstånd motfrostnedbrytning med de mest optimistiska värdena för luftporernas avståndsfaktor och specifikayta.

Выпускная квалификационная работа, 67 с., 9 рис., 9 табл., 25 источников. Объект исследования – способы плавки медных концентратов. Предмет исследования – поиск наиболее эффективного способа плавки медных концентратов. Цель работы – провести ряд технологических и экономических расчетов, на основании которых определить наиболее эффективный способ плавки медных концентратов. В процессе работы были проведены расчеты материальных балансов и тепловых балансов для выбранных способов плавки медных концентратов. Также проведен сравнительный анализ выбранных способов плавки по полученным результатам расчетов и проведена предварительная экономическая оценка инвестиционного проекта, предполагающего замену отражательных печей предприятия ОАО «Святогор» на печи, являющимися основным оборудованием для того способа плавки, который будет выбран наилучшим по результатам анализа. В результате работы был сделан вывод об эффективности выбранных способов плавки медных концентратов относительно друг друга, среди которых был выбран наиболее эффективный способ плавки. А также проведена предварительная экономическая оценка инвестиционного проекта, предполагающего замену отражательных печей предприятия ОАО «Святогор» на печи, являющимися основным оборудованием для того способа плавки, который будет выбран наилучшим по результатам анализа. / Final qualifying work, 67 pp., 9 pics., 9 tables, 25 references Object – methods of melting copper concentrates. Subject – search for the most effective method of melting copper concentrates. The purpose of the work is to carry out a number of technological and economic calculations on the basis of which the most effective method of melting copper concentrates is determined. In the course of work, material balances and heat balances were calculated for the selected methods for melting copper concentrates. The analysis of the selected melting methods was also carried out based on the results of calculations, and a preliminary economic evaluation of the investment project was carried out, involving the replacement of the reflector furnaces of the Svyatogor enterprise with the furnace, which is the main equipment for the melting method to be chosen as best according to the analysis. As a result of the work, a conclusion was made about the effectiveness of the chosen methods of melting copper concentrates relative to each other, among which the most effective method of melting was chosen. Also, a preliminary economic evaluation of the investment project was carried out, which involves replacing the reflective furnaces of the Svyatogor enterprise with the furnace, which is the main equipment for the melting process, which will be chosen the best according to the results of the analysis.

The thesis is devoted to the development of software for the system of optimal distribution of fuel and energy resources in the group of blast furnaces. In the course of work, the main stages of software development are considered: analysis of the subject area; creation of software architecture, user interface, database structure; development of algorithmic support and reference documentation; preparation of the distribution. The result of the work is a software product intended for the engineering and technological personnel of the blast furnace shop of the metallurgical plant. The results of the work can also be used in the educational process for training bachelors and undergraduates in the areas of "Metallurgy" and "Information Systems and Technologies". / Диссертационная работа посвящена разработке программного обеспечения системы оптимального распределения топливно-энергетических ресурсов в группе доменных печей. В ходе работы рассмотрены основные этапы разработки программного обеспечения: анализ предметной области; создание архитектуры программного обеспечения, пользовательского интерфейса, структуры базы данных; разработка алгоритмического обеспечения и справочной документации; подготовка дистрибутива. Результатом работы является программный продукт, предназначенный для инженерно-технологического персонала доменного цеха металлургического комбината. Результаты работы могут быть использованы также в учебном процессе для обучения бакалавров и магистрантов по направлениям «Металлургия» и «Информационные системы и технологии».

This final qualification work is devoted to assessing the effectiveness of our own production and industrial outsourcing using the example of OOO Metallpromiks, and also presents the development directions and their economic feasibility. Graduation work consists of 3 chapters. The first chapter discusses the forms, types of outsourcing, the positive and negative sides, as well as the scope and risks associated with it. In the 2nd chapter, an analysis of financial and economic activities and product mix of OOO Metallpromiks is carried out. In the 3rd chapter, measures are developed to increase the efficiency of the enterprise’s development and the calculation is made using the example of OOO Metallpromiks. The work contains 81 pages, 18 tables, 30 figures, the list of sources used consists of 30 points. / Данная выпускная квалификационная работа посвящена оценки эффективности собственного производства и промышленного аутсорсинга на примере ООО «Металлпромикс», а также представлены направления развития и их экономическая обоснованность. Выпускная работа состоит из 3 глав. В 1-й главе рассмотрены формы, виды аутсорсинга, положительные и отрицательные стороны, а также сферы применения и риски с ним связанные. Во 2-й главе проведен анализ финансово-хозяйственной деятельности и товарного ассортимента ООО «Металлпромикс». В 3-й главе разработаны мероприятия по повышению эффективности развития предприятия и произведён расчёт на примере ООО «Металлпромикс». Работа содержит 81 страницу, 18 таблиц, 30 рисунков, список использованных источников состоит из 30 пунктов.

Целью работы является изучение влияния донной продувки в промежуточном ковше на содержание неметаллических включений в транспортном металле и пути повышения качества данных марок стали. В качестве решения проблемы рассмотрена гипотеза о зависимости содержания неметаллических включений в стали от состава шлака на установке «печь-ковш»; создана физическая модель МНЛЗ; предложена схема расположения аргонных блоков в промежуточном ковше, что позволит создать оптимальные потоки металла для флотации неметаллических включений. / The aim of the work is to study the effect of bottom blowing in the intermediate bucket on the content of non-metallic inclusions in the transport metal and ways to improve the quality of these steel grades. As a solution to the problem, the hypothesis of the dependence of the content of non-metallic inclusions in steel on the composition of the slag at the furnace-ladle installation is considered; a physical model of the CCM is created; a scheme for the arrangement of argon blocks in the intermediate ladle is proposed, which will create optimal metal flows for flotation of non-metallic inclusions.

Utsläppen av växthusgaser ökar över hela världen och nya tekniker används för att minska utsläppen. 7% av utsläppen kommer från stålsektorn. 25% av världens stålproduktion görs via återvinningstekniken ljusbågsugn. Genom återvinningsprocessen släpps det ut 500kg CO2 per ton producerat flytande stål. En möjlighet att sänka dessa direkta utsläppär att koppla ljusbågsugnsprocessen med biomassa förgasnings och koldioxidavskiljning. Den föreslagna lösningen i denna avhandling är att utnyttja avgaserna från stålsmältningen i förgasningsprocessen och skapa värdefulla produkter. Projektet utvärderar den tekniska genomförbarheten i form av energieffektivitet och kolutnyttjande. Den föreslagna processen simulerades med Aspen Plus. Ett problem med ljusbågsugnens avgaser är fluktuationen i sammansättningen. Tre fall avavgassammansättning undersöktes. Fall 1 var den genomsnittliga avgassammansättningen, medan fall 2 och 3 var extrema med högt CO- respektive CO2-innehåll. Resultatet visade att syntetsgassammansättningen starkt beror på förgasningsmedlet. I samtliga fall ökade energieffektiviteten och de direkta utsläppen minskade, jämfört med nuvarande process. Fall 1 visade generellt högst effektivitet och kolutnyttjande, medan det CO2 rika fallet (fall 3) hade lägst. Ett kontinuerligt flöde av förgasningsmedel krävs för att driva förgasningsprocessen. Eftersom ljusbågsugn är en satsvis process, sker luftförgasning när avgaser inte är tillgängliga. Det önskade resultatet av luftförgasning är att producera syntetsgas som liknar avgasförgasningens syntesgas. Resultaten visade att luftinfiltration i avgaser är gynnsamt för mer liknande syntesgas . / Greenhouse gas emissions are increasing worldwide, and new techniques are being adopted to suppress the emissions. The steel sector is responsible for 7% of the emissions. 25% ofthe world’s steel production is made through the recycling technique EAF. Throughout the recycling process, 500 kg CO2 gets emitted per ton of liquid steel produced. An opportunity to lower these direct emissions is to couple the EAF process to biomass gasification and CO2 utilisation process. The proposed solution in this thesis is to utilise the off-gases in the gasification process and create high-valuable products. The project evaluates the technical feasibility via energy efficiency and carbon utilisation. The proposed process was simulated using Aspen Plus. A problem with the off-gases from EAF gasification is the fluctuation in composition. Three cases of off-gas composition were therefore investigated. Case 1 was the average off-gas composition, while cases 2 and 3 were extreme with high CO and CO2 content, respectively. The result showed that the syngas composition strongly depends on the gasifying agent. In all cases, the energy efficiency increased, and the direct emissions decreased. Case 1 generally showed the highest efficiency and carbon utilisation, while the CO2 heavily case (case 3) had the lowest. A continuous flow of gasifying agents is required to run the gasification process. Since EAF is a batch process, air gasification runs when off-gases are unavailable. The desired outcome of air gasification is to produce syngas similar to off-gas gasification. The results showed that air infiltration in off-gases is favourable for more similar syngas composition.

[pt] Um modelo de descarburação e formação de escórias foi desenvolvido e aplicado ao processo de fabricação de aço em forno elétrico a arco de 120 ton de capacidade, com carga de ferro gusa e de sucata ferrosa. O carregamento de carbono foi significativamente variado para testar a consistência do modelo, considerando a cinética de oxidação do carbono, oxidação do fósforo e de redução do óxido de ferro. Gusa e coque foram empregados como fontes mais relevantes de carbono, resultando na entrada de 15 a 35 kg carbono/ton. As taxas de fusão do gusa e da sucata governam a disponibilidade dos elementos mais relevantes tais como carbono, fósforo e silício em solução, portanto, afetam as taxas de descarburação e de formação de escórias. A principal fonte de fósforo na carga ferrosa é o gusa. Desta forma, a evolução do teor de fósforo na fase metal mostrou-se importante para as estimativas das taxas de fusão do gusa, uma vez que o fósforo pode ser empregado como traçador adicional ao carbono. Modelos cinéticos envolvendo as reações do fósforo e silício operam simultaneamente com os modelos cinéticos referentes às reações do carbono e do ferro. Integrações numéricas associadas a um algoritmo de gradientes reduzidos generalizado foi empregado para o sistema não linear com restrições, de forma a determinar a maioria dos parâmetros cinéticos do modelo. A taxa de fusão global da carga de sucata foi maior do que a taxa de fusão aparente do gusa. Supõe-se que, o gusa apesar de ter relações geométricas desfavoráveis à transferência de calor em relação à sucata, poderia fundir mais rapidamente influenciado pelo seu baixo ponto de fusão. Entretanto, devido à formação de camada solidificada a partir da massa líquida na qual é imerso, é provável que mesmo fundido posteriormente, ocorra um processo de encapsulamento temporário, conferindo-lhe uma taxa aparente de fusão mais baixa. A constante cinética da reação de descarburação quando o teor de carbono é inferior ao carbono crítico de 0.19 por cento em massa e pelo menos 60 por cento da carga ferrosa estão fundidas, foi estimada em 0.74 min-1, taxas comparáveis às obtidas em aciaria a oxigênio. A principal fonte de oxigênio para oxidação do ferro é disponibilizada por lanças supersônicas. Estima-se que 20 por cento do oxigênio injetado via lanças sejam consumidos para a formação de óxido de ferro. Entretanto, cerca de 31 por cento e 26 por cento do oxigênio oriundo de injetores de póscombustão podem contribuir na formação de óxido de ferro ou são captados pelo sistema de exaustão de gases, respectivamente. Os resultados indicam que em torno de 15-30 por cento do carbono injetado podem não reagir no forno, sendo removidos com a escória. Adicionalmente ao estado de não-equilíbrio no sistema Fe-C-O observado, a dispersão nas estimativas de carbono solúvel na fase metal também pode ter sido influenciada pela intensidade de penetração da injeção de coque. O algoritmo proposto se constitui num promissor simulador de práticas que visam otimizar o rendimento metálico do ferro, a partir da dependência da cinética de redução do óxido de ferro com sua atividade química na escória. / [en] A decarburization and slag formation model was developed and applied to a steelmaking process based on scrap and pig iron mixes melted in a conventional AC electric arc furnace (EAF) with 120 ton capacity. The amount of carbon input was varied significantly in order to evaluate the model consistency regarding mainly the kinetics of carbon oxidation, phosphorus oxidation and iron oxide formation and reduction. Pig iron and coke were used as sources of carbon, resulting in variation of total carbon input in the range of 15 to 35 kg carbon/ton. The pig iron and scrap melting rates determine the availability of the most relevant elements such as carbon, phosphorus and silicon in solution in Fe-C melts, and therefore, affecting the decarburization as well the slag formation rates. The pig iron is the main source of phosphorus in the ferrous charge. Hence, the evolution of the phosphorus content in the metal phase is important to predict the pig iron melting rate, since phosphorus can be used as a tracer element in addition to carbon. Kinetic models regarding phosphorus and silicon were applied simultaneously to kinetic models of carbon and iron reactions. A numerical integration method supported a generalized reduced gradient algorithm for non-linear and constrained system (GRG) was applied to determine most of the kinetic model parameters. The scrap melting rates were found to be higher than pig iron apparent melting rates. This is expected that, even though the heat transfer issues related to significant differences in the area to volume ratio compared to scrap, pig iron may melt faster influenced by its low melting point. However, a solidified shell maybe created from the hot heel where pig iron is immersed, even when further melting occur, Fe-rich carbon melts could be encapsulated temporarily and present lower apparent melting rate. The decarburization rate parameter, when at least 60 percent of the charge is melted, was estimated as 0.74 min-1, when carbon content is lower than the critical carbon 0.19 percent wt, which is similar to the rate range observed in oxygen steelmaking facilities. Around 31 percent and 26 percent of the oxygen input through post combustion injectors were addressed to iron oxidation and to the off-gas system, respectively. The main source of oxygen taking part of iron oxidation is available from supersonic lances. Approximately 20 percent of the oxygen input through lancing are consumed to form iron oxide. The results also indicate about 15-30 percent of the injected carbon may not react and leave EAF during slagoff. In addition to the observed non-equilibrium state in Fe-C-O system, the dispersive behavior of the prediction of soluble carbon content in the metal phase could also be influenced by the intensity of penetration coke. The model framework is a promising tool to work preliminarily in what-if process scenario builder as a static model for iron yield optimization, regarding the kinetics of iron oxide reduction reaction and the proposed dependence on its chemical activity in the slag phase.