Book of abstracts of the 14th International Symposium of Croatian Metallurgical Society - SHMD \u272020, Materials and metallurgy

Book of abstracts of the 14th International Symposium of Croatian Metallurgical Society - SHMD \u272020, Materials and metallurgy held in Šibenik, Croatia, June 21-26, 2020. Abstracts are organized in four sections: Materials - section A; Process metallurgy - Section B; Plastic processing - Section C and Metallurgy and related topics - Section D

Feasibility study to extract iron and chromium from chromium contaminated soils

Chromium contaminated soils, besides being recognized for toxic and hazardous hexavalent chromium, contain high iron concentrations. At some sites, concentrations of iron oxide are higher than 30%. Both iron and chromium in soils have recyclable value provided they can be either concentrated in the oxide form or separated as metal. The concentrated oxide can be used as a substitute for the iron ore. The extracted metal can also be recycled in the steel industry. The objective of this study is to study the feasibility of extracting iron and chromium from soils. Chromium contaminated soils, can be classified into two groups, one with high iron content having magnetic properties, and the other with low content of iron with no magnetic properties. The extraction of iron and chromium in their oxide forms was conducted using magnetic and gravitational separation techniques. The magnetic separation was found to be better than gravitational separation to concentrate iron and chromium from chromium contaminated soils for the experimental setup. However, the iron content in soil could not be concentrated to as high a level as high grade or processed iron ore, 60-70% iron content. The reduction of iron oxide to metal can be accomplished at high temperature under the reducing environment. The reduction of iron oxide in soil was quite rapid at temperature higher than 1100°C. The solid carbon was used as a reducing agent for the study of reduction in Thermo-Gravimetric Analyzer. The reduction process was found to be controlled by gasification with the activation energy of 45-55 kcal/mol based on the selected kinetic models. The complete reduction required at least 15% of carbon by weight. The metal agglomeration and separation occurred when sand was added to soils. The substantial percentage of metal, 15-32 %, was separated from GAR and TPR soils mixed with 15-25% of sand and 15% carbon. The LSP soil mixtures yielded metal separation with sand addition above 20%. Phase and viscosity diagrams were used to explain the metal separation and behavior of the slag. Experimental results demonstrated that iron and chromium can be extracted from chromium contaminated soils found in Hudson County, NJ

Book of abstracts of the 16th International Symposium of Croatian Metallurgical Society - SHMD \u272023, Materials and metallurgy

Book of abstracts of the 16th International Symposium of Croatian Metallurgical Society - SHMD \u272023, Materials and metallurgy, Zagreb, Croatia, April 20-21, 2023. Abstracts are organized into five sections: Anniversaries of Croatian Metallurgy, Materials - Section A; Process Metallurgy - Section B; Plastic Processing - Section C and Metallurgy and Related Topics - Section D

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

Multi-lifecycle assessment of cathode ray tubes

Over the past few years environmental issues and concerns have become more and more important, as they become a common part of most people\u27s personal experience. In these regards, the electronics industry is facing substantial problems in terms of end-of-life management of its products, televisions and monitors in particular. The building blocks of this industry are usually viewed as relatively clean . However, manufacturing by-products of the electronics industry and the disposition of electronics are becoming increasingly important technical, financial, and environmental issues. Within the context of the above issues, environmentally responsible disposal of Cathode Ray Tubes (CRT\u27s), which is still the prominent display of choice for both the television and the computer monitor, is regarded as a major concern, due to the high amount of lead in the CRT glass. A considerable proportion of the environmental effects of a CRT is related to its lifecycle and also to the lifecycle of its materials. And hence to analyze and assess the environmental impact of the raw materials used in a CRT during its complete lifecycle, the method of Multi-Lifecycle Assessment (MLCA) is adopted in this research and thesis. A generic process modeling structure for manufacture of materials is developed to conduct a full inventory analysis, in terms of mass balance, energy balance and environmental performance. The demanufacturing aspect of televisions is also addressed. The disassembly process is studied and different disassembly levels are analyzed using the reverse fishbone diagram technique. Considering three different end-fate objectives for recovering the subassemblies, components, and materials in the television, a cost effectiveness analysis is also performed to compare end-fate objectives and determine the scenario yielding the highest value for disassembling televisions. The major contributions and results obtained from this research are as follows: A database for eco-profile of commonly used materials namely, steel, aluminum, copper, lead, and leaded-glass, is generated by conducting LCI of these materials. Environmental burden for the lifecycle of CRT from raw materials extraction to production is calculated. The demanufacturing study conducted suggested that, for profitable and economical operation of a disassembly process, the procedure and level of disassembly, the time required for disassembly, and the current market value of recovered materials, are important and dependent on each other. The demanufacturer has to make a trade-off between these issues and thus try to efficiently and effectively manage the entire demanufacturing operation

Advances in Pyrometallurgy

There are several major megatrends having an impact on pyrometallurgical metal processing. The steadily growing demand for all metals is strengthened by the emergence of electrical vehicles (EV), which brings a high need for battery metals, but additionally, a significant increase in copper consumption. Even if only moderate forecasts for the number of the EVs become true, production of the base metals must increase by tens of percentages, or even more than double. At the same time, pyrometallurgical processes have to produce fewer side products, such as slag, and maintain the quality level of the primary product, although raw material mixtures are increasingly complex and new elements are entering the processes in secondary raw materials. Therefore, it is imperative to continue the development of pyrometallurgical processes more efficiently and productively, while still improving their selectivity regarding slagging the unwanted material and recovering the desired elements. This Special Issue is for current advances in the pyrometallurgical processing of metals, including all aspects, namely, the basic unit processes and operations in a smelter, metallurgical engineering, furnace integrity, cooling systems, modelling, slag and offgas handling, to name a few. A collection of 13 papers deal with ferrous and ferroalloy development, and the processing of different raw materials for metal production

Reduction of scrap percentage of cast parts by optimizing the process parameters

Casting is a widely used manufacturing process in the automotive industry. Die casting is the most popular type of casting processes. But the fact observed in many industries is the scraps or wastages occurring after the process. Thus, this thesis is primarily based on understanding the die-casting process and the factors governing them. In this study, the part to be studied is a throttle body. The raw material used for the production is AlSi9Cu3. The main concern in this part is the occurrence of defects such as bad filling, heat bubbles, and porosity. Thus, it is important to perform process optimization. Techniques or methods such as Design of Experiments, ANOVA analysis, and numerical simulations are used. This thesis also focuses on the use of brainstorming as an industrial discussion tool and the use of quality tools for process optimization. Thus, these techniques are utilized in order to eliminate the defects. The scrap after using these techniques and methods is reduced to 9% from 14% initially found. This investigation has been performed as a continuous improvement project in Sonafi and as a master thesis for “Instituto Superior de Engenharia do Porto”.A fundição é um processo de fabrico amplamente utilizado na indústria automóvel. A fundição injetada é o tipo mais popular de processos de fundição. Mas, o facto observado em muitas indústrias é o aumento de sucatas ou desperdícios que ocorrem após o processo. Assim, esta tese é baseada principalmente na compreensão do processo de fundição e nos factores que a governa. Neste estudo, a parte a ser estudada é um corpo do acelerador. A matéria-prima usada para a produção é AlSi9Cu3. A principal preocupação nesta parte é a ocorrência de defeitos como mau preenchimento, bolhas de calor e porosidade. Assim, é importante realizar a otimização do processo. São utilizadas métodologias como o Desenho de Experiências, análise ANOVA e simulações numéricas. Esta tese também se concentra no uso do brainstorming como uma ferramenta de discussão industrial e uso de ferramentas de qualidade para otimização de processos. Assim, essas técnicas são utilizadas para eliminar problemas ocorridos na produção. Esta investigação foi realizada como um projeto de melhoria contínua na Sonafi e como uma tese de mestrado para o Instituto Superior de Engenharia do Porto

Ανάπτυξη μεθόδων για τη συντήρηση-αποκατάταση σιδηρών αρχαιολογικών αντικειμένων από θαλλάσιο περιβάλλον

246 σ.Τα χρόνια υπολείμματα σιδήρου που συναντάμε σε αρχαιολογικά ευρήματα μέσα στην θάλασσα είναι σπάνια σε καλή κατάσταση. Η μακροχρόνια παραμονή των αντικειμένων στο θαλάσσιο περιβάλλον, συχνά οδηγεί σε πορώδη κατάσταση, ευθρυπτότητα, εναπόθεσn αλάτων, υλική φθορά και σοβαρή διάβρωση με συνέπεια τη μείωση της διάρκειας ζωής των αντικειμένων. Από το σύνολο των ενώσεων που περιέχουν χλώριο, ο ακαγανίτης είναι το μόνο που εντοπίστηκε από το ΧRD (περίθλαση ακτίνων Χ) σε πειράματα σιδήρου και αντικειμένων. Επίσης, ιόντα χλωρίου εντοπίστηκαν από το νιτρικό άργυρο και το EDS (Φασματόμετρο Ενεργειακής Διασποράς) . Η αποχλωρίωση είναι απολύτως απαραίτητη για τη διατήρηση των αντικειμένων σιδήρου. Η αφαλάτωση είναι μία από τις πιο επίπονες και χρονοβόρες από τις θεραπείες συντήρησης. Τα αποτελέσματα με XRD (περίθλαση ακτίνων Χ), EDS (Φασματόμετρο Ενεργειακής Διασποράς) και δοκιμές νιτρικού αργύρου απέδειξαν ότι τα αντικείμενα από χυτοσίδηρο περιέχουν χλώριο σε ποσό μεγαλύτερο από αυτό των αντικειμένων σφυρήλατου σιδήρου πριν από τη θεραπεία. Η αποτελεσματικότητα των μεθόδων θεραπείας με αποχλωρίωση εξαρτάται από την απομάκρυνση ιόντων χλωρίου και την τελική εμφάνιση των αντικειμένων με τη χρήση περαιτέρω μεθόδων έρευνας και αναλύσεων. Έγινε προσπάθεια σε αυτή τη μελέτη να αξιολογηθούν οι μέθοδοι επεξεργασίας αφαλάτωσης που μπορεί να εξοικονομήσουν χρόνο και να αφαιρέσουν ένα μεγάλο ποσοστό χλωρίου από τα αντικείμενα σιδήρου. Πολλές μέθοδοι αφαλάτωσης ή αποχλωρίωσης του σιδήρου σε αντικείμενα από το θαλάσσιο περιβάλλον, μπορούν να χρησιμοποιηθούν στα εργαστήρια συντήρησης ή σε θαλάσσιες επιτόπου εκσκαφές για την πρόληψη περαιτέρω βλάβης μετά την απομάκρυνση του αλατούχου περιβάλλοντος. Τέσσερις μέθοδοι αποχλωρίωσης των υποθαλάσσιων αρχαιολογικών αντικειμένων σιδήρου χρησιμοποιούνται στο Δημόκριτο ως χημική επεξεργασία με καυστικό νάτριο (NaOH) και / ή υδρογόνο του πλάσματος. Οι πρόσφατες εργασίες στο πλάσμα υδρογόνου, οδήγησαν στην επιλογή αυτής της μεθόδου για αποχλωρίωση. Από τη βιβλιογραφική ανασκόπηση της αφαλάτωσης, το χημικό διάλυμα καυστικού νατρίου είναι το πιο αποτελεσματικό στη θεραπεία αφαλάτωσης του σιδήρου αρχαιολογικών αντικειμένων. Τα συμπεράσματα των πειραματικών δοκιμών έχουν ως εξής: Ο καλύτερος τρόπος για την αφαλάτωση των θαλάσσιων αντικειμένων σιδήρου, είναι βυθίζοντας τα, αρχικά σε 1-2% καυστικό νάτριο με 13,5 pH και έπειτα χρησιμοποιώντας τη μέθοδο μείωσης του πλάσματος. Μετά από την εφαρμογή αυτών των μεθόδων, είναι λιγότερο πιθανό τα εκθέματα του σιδήρου να ξανά- διαβρωθούν. Η δημιουργία ενός σταθερού στρώματος σε αντικείμενα σιδήρου μετά τη χρήση του 1-2% NaOH σε συνδυασμό με τη μέθοδο μείωσης του πλάσματος ολοκληρώθηκε. Σε θερμοκρασία από 80 έως 300°C, το πλάσμα δεν επηρεάζει χημικά την επιφάνεια ή τις μεταλλουργικές ιδιότητες του αντικειμένου. Τα περισσότερα από τα ιόντα χλωρίου απελευθερώθηκαν κατά τη διάρκεια του αρχικού σταδίου της αφαλάτωσης. Ο στόχος της αποχλωρίωσης είναι να μάθουμε αν μία από αυτές τις μεθόδους είναι βολική για τον συντηρητή, για τη σταθεροποίηση των αντικείμενων μετάλλου από το θαλάσσιο περιβάλλον. Από τη δουλειά που κάναμε, μπορούμε να πούμε ότι οι σύγχρονες τεχνολογικές μέθοδοι, όπως η μείωση του πλάσματος, χρησιμοποιήθηκαν για να υποστηρίξουν τις συμβατικές μεθόδους της διατήρησης των αρχαιολογικών αντικειμένων, όπως είναι η μηχανική και η χημική επεξεργασία. Το ποσοστό των αφαιρεθέντων χλωριδίων αυξήθηκε με το χρόνο και την θερμοκρασία του πλάσματος. Η ίδια εξάρτηση από το χρόνο και τη θερμοκρασία παρατηρήθηκε για την αφαλάτωση με καυστικό νάτριο. Λίγα πειράματα, καθώς και δύο αντικείμενα σιδήρου ήταν εντελώς απαλλαγμένα από χλωρίδια, ενώ η μεγαλύτερη ποσότητα των χλωριδίων αφαιρέθηκε από τα υπόλοιπα σιδερένια αντικείμενα.The survivors of iron artifacts in marine archaeological conditions are rarely in a good state. Long term burial of the artifacts in the marine environment often leads to porous, pits friability, salt encrustation, physical damage and severe corrosion that lead to reduce the lifetime of the metal artifacts. Among the variety of chlorine containing compounds, akaganeite is the only one that was evaluated by XRD in the iron coupons and artifacts. Also, chloride ions were assessed by silver nitrate test and EDS. The removal of chloride ions is absolutely essential for the conservation of iron artifacts. Desalination treatment is one of the most laborious and time-consuming of conservation treatments. The results by X-ray diffraction, EDS (Energy dispersive spectrometer) and silver nitrate test proved that cast iron artifacts contain chlorides at higher amount than the wrought objects before the treatment. The efficiency of dechlorination treatment methods is often compared by determining the chloride ion removal and the final appearance of the objects by using further methods of investigation and analyses. We tried in this study to assess desalination treatment methods that can save time and remove a large percentage chloride from the iron artifacts. Many methods of desalination or dechlorination of iron artifacts from the marine environment can be utilized in the conservation laboratories or in marine excavation situ to prevent further damage after being removed from the saline environment. Four methods of dechlorination of underwater iron archaeological objects are used in Demokritos as chemical treatment (NaOH) and/or hydrogen plasma reduction. Recent successes in hydrogen plasma led us to choose this method for dechlorination. From the literature review of desalination, the chemical solution such as sodium hydroxide is the most effective one in the desalination treatment of iron archaeological objects. The conclusions of the experimental tests are as follows: The best way for desalination of the marine iron artifacts is by immersing them firstly in 1-2% sodium hydroxide in 13.5-pH combined with plasma reduction. After the application of these methods, it is less probable for the iron artifacts to be re-corroded. The formation of a stable passivating layer on iron surface artifacts after using 1-2% NaOH combined with plasma reduction was accomplished. At 80 to 300°C, the plasma does not chemically affect the surface or the metallurgical properties. Most of the chloride ions were released during the early stage of desalination. The objective of the dechlorination is to find out if one of these methods is convenient for the conservator to stabilize the metal artifacts from the marine environment. From our work, we can say that modern technological methods, such as plasma reduction, was used to support the conventional methods of conserving archaeological objects as mechanical and chemical treatment. The percentage of removed chlorides increased with time; and temperature of the plasma. The same dependence on time and on temperature was observed for the desalination with sodium hydroxide. The few coupons, as well as the two iron artifacts were completely free from chlorides, while the major quantity of chlorides was removed from the others iron objects.Saleh Mohamed Saleh Ahme