• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Drahtziehen und die dazugehörigen Werkzeuge im Altertum

Özşen, Ilyas 11 January 2023 (has links)
Die vorliegende Dissertation beschäftigt sich mit der Fragestellung, ob das Drahtziehverfahren bereits im Altertum zur Anwendung kam und nicht, wie in der bisherigen Forschung angenommen, erst im Frühmittelalter einsetzte. Um diese Fragestellung zu klären, wurden Drähte unterschiedlicher Produktgattungen untersucht und experimentalarchäologisch mit der Expertise des Goldschmieds und Restaurators Frank Willer nachgeahmt. Während einige Drähte aus einem Blech gezogen sind, konnte für den Draht des Kettenpanzers aus der Tiefenau bei Bern anhand einer metallographischen Analyse das Ziehen aus einem massiven Rohling nachgewiesen werden. Auch die Untersuchung der für das Drahtziehen benötigten Werkzeuge unterstützt die Annahme, dass das Drahtziehverfahren früher als bisher vermutet bekannt gewesen war. Durch eine materialwissenschaftliche Analyse der Zieheisen und -bronzen konnte nachgewiesen werden, dass diese Werkzeuge den Anforderungen für das Ziehen von Drähten entsprechen. Ein weiteres Argument für das Drahtziehen im Altertum besteht aus der chronologischen und geographischen Korrelation zwischen dem Einsetzen von Kettenpanzern und dem Aufkommen von Zieheisen innerhalb des Latènekreises. Für die Produktion von Kettenpanzern wurde Draht in großen Mengen benötigt, weswegen die Nutzung des im Vergleich ökonomischeren Drahtziehverfahrens naheliegend ist. Somit lässt sich das Ziehen von Drähten zwar schon vereinzelt für die Bronzezeit nachweisen, doch eine weite Verbreitung dieser Innovation geschieht erst ab der Früh- oder Mittellatènezeit mit der Nutzung von Kettenpanzern. Solch eine verzögerte Diffusion einer Innovation stellt keine Ausnahme innerhalb der Technikgeschichte dar und ist dadurch zu erklären, dass eine Innovation, die nicht fortgeführt wurde, an einem geographisch und zeitlich unterschiedlichem Punkt der Geschichte erneut auftreten kann, da es sich um eine konvergente Entwicklung handelt, bei der dieselben Rahmenbedingungen und Anforderungen vorliegen. / The doctoral thesis examines the question of whether the wire drawing process was already used in antiquity and not, as assumed in previous research, first began in the early Middle Ages. In order to elucidate this question, the wires of different products were examined and imitated experimentally with the expertise of the goldsmith and conservator Frank Willer. While some wires were drawn from a sheet metal, by metallographic analysis the wire of the mail armour from Tiefenau near Bern was drawn from a solid blank. The investigation of the tools required for wire drawing also supports the assumption that the wire drawing process was known earlier than previously assumed. A materials science analysis of the drawplates showed that these these Bronze and Iron Age tools met the requirements for wire drawing. Another argument for wire drawing in antiquity is the chronological and geographical correlation between the introduction of mail armour and the frequent use of drawplates within the Latène circle. The production of mail armour required considerable quantities of wire, so the use of the more economical wire drawing process compared to hammering or torsion techniques is obvious. Although the drawing of wire can be proven for the Bronze Age in certain cases, this innovation was not widely spread and established until the Early or Middle Latène Period onwards with the use of mail armour and the accompanying higher demand for wires. Such a delayed diffusion of an innovation is not an exception within the history of technology and can be explained by the fact that an innovation that was not continued can reappear at a geographically and temporally different point in history, since it is a convergent development in which the same underlying conditions and requirements are present.
2

Leaching of copper and gold concentrate in the presence of halides

Togtokhbaatar, Purev-Ochir 22 July 2024 (has links)
Ionometallurgy is a new trend to utilise ionic liquids as alternative green solvents for oxidic and sulfidic copper minerals. It has broad potential for traditional pyrometallurgy and hydrometallurgy. Ionometallurgy utilises ionic liquids (ILs), highly potent complexing ligands (chloride), to process oxide and copper sulfide minerals. This work focused on using the deep eutectic solvents (DES) of ionic liquids, which and provide alternative options for processing various metals, alloys, and concentrates. For this job, various analytical methods were used to determine the copper concentrate and its residue after leaching (MLA-SEM and XRPD), quantify the elements in the solution (IC and ICP-OES/MS) and explain the oxidation behaviour (CV and UV-Vis spectroscopy). Combining the analytical and electrochemical methods to the leaching experiment provided the control to improve the results and understand its oxidation behaviour. Chosen DES, Oxaline (ChCl + oxalic acid, 1:1), and Ethaline (ChCl + ethylene glycol, 1:2) were tested and enhanced on the actual copper concentrates with and without oxidative additives (FeCl3 and I2). Those oxidative additives are selected for leaching experiments by their redox potential in Ethaline. However, there are many acceptable values; the most exciting result related to Ethaline plus iodine was the potential leaching system for chalcopyrite and copper-gold concentrates leaching. Because ion chromatography (IC) and UV-Vis’s analysis confirm iodine oxidizes the Cu+ species quickly in Ethaline. Whilst identical results and oxidation behaviour appeared in chalcocite (Cu2S), chalcopyrite (CuFeS2) and copper-gold concentrates leaching. During the iodine reduction to iodide in the system, IC proved that chalcopyrite releases the Fe3+, oxidizing the chalcopyrite particles. Also, iodine oxidized the natural gold in copper-gold concentrate successfully, and gold concentration quantified ICP-MS and MLA-SEM proved there is no visible gold in the leaching residue. Based on the optimal Ethaline + I2 leaching condition, the copper concentrate was carried out with the bottle roller leaching to represent the tank leaching. Thus, DES shows that it has a high potential to be continued to scale up the experiment. Also, water was given to the Ethaline leaching system, and water had a good influence on the leaching due to reducing the viscosity and saving the Ethaline amount. Hence Ethaline plus water is used for the copper ore leaching in the column, and it can be seen that Ethaline + I2 with water (up to 20%) has a high potential to process the low-grade copper sulfide ores.:Acknowledgements Abstract Abbreviations TABLE OF CONTENTS CHAPTER ONE – INTRODUCTION OF COPPER PROCESSING TECHNOLOGIES 1.1. Overview 1.2. Copper 1.3. Gold 1.4. Hydrometallurgy and pyrometallurgy of copper and gold 1.5. Current copper and gold concentrate processing methods 1.6. An alternative copper concentrate processing method Summary of chapter 1 CHAPTER TWO – FUNDAMENTALS FOR PROCESS DEVELOPING 2.1. Introduction 2.2. Effect of temperature and stirring in leaching 2.3. Analytical methods and experimental 2.4. Experimental for leaching 2.5. Discussion of experimental errors CHAPTER THREE: ANALYTICAL EXPERIMENTS FOR LEACHING 3.1. Introduction 3.2. Analysis of copper concentrate 3.3. Cyclic voltammetry 3.4. UV-Vis spectroscopy analysis of target metals 3.5. Metals solubility in DES 3.6. Summary and conclusions CHAPTER FOUR: FUNDAMENTAL LEACHING EXPERIMENT AND INITIAL INVESTIGATION 4.1. Introduction 4.2. Initial study and fundamental leaching experiments 4.3. Study of mineral oxidation 4.4. Deep eutectic solvents leaching 4.5. Chapter summary and conclusion CHAPTER FIVE: LEACHING OF MODEL SYSTEMS IN ETHALINE WITH OXIDATIVE ADDITIVES 5.1. Introduction 5.2. Iodine effect on Cu2S and CuS leaching in Ethaline 5.3. Ferric chloride effect on CuS and Cu2S leaching 5.4. Leaching of natural gold in Ethaline with the presence of iodine 5.5. Cyclic voltammetry investigation of Cu+/2+ sulfides in DES 5.6. Chapter summary and conclusion CHAPTER SIX: LEACHING OF COPPER-GOLD CONCENTRATES IN DES AND WITH OXIDATIVE ADDITIVES 6.1. Introduction 6.2. Effect of ferric chloride (FeCl3) 6.3. Effect of iodine (I2) 6.4. Electrochemical and spectroscopic analysis of copper-gold concentrate leachates 6.6. Chapter summary and conclusion CHAPTER SEVEN: OVERALL CONCLUSION AND FUTURE WORK 7.1. Overall conclusions 7.2. Recommendations for future research CHAPTER EIGHT: APPENDIX 8.1. Chemicals and materials 8.2. Appendix References

Page generated in 0.0611 seconds