Stefan Luidold

Montanuniversität Leoben · Chair of Nonferrous Metallurgy, CD Laboratory for Extractive Metallurgy of Technological Metals

Recycling of cemented carbides is an essential part of resource conservation of critical raw materials and is therefore of particular ecological, economic and strategic importance. These composite materials , consisting of refractory carbides embedded in a metallic binder, can be recycled in various ways, whereas the so-called zinc process has the...

Technological advances set new challenges for materials development. Miniaturization of electronic devices demands the migration of metallurgy from macro/micro to the nanoscale, thus requiring a re-definition of existing and classical concepts in metallurgy. The present study reports on the behaviour of pure Cu nanowires with diameters ranging from...

In cemented carbides cobalt serves as a binding agent between tungsten carbide grains. The zinc process exhibits an important technique to recycle these materials. Since the decomposition takes place at temperatures of 900–1000 °C the role of gaseous zinc in this process is poorly investigated. A specific experimental set-up was used to ensure that...

Viscosity and melting behavior are two of the most important properties of industrial slags as they directly impact the yield of metallurgical processes. Too high fluidity may cause losses during tapping or infiltration of refractory while too viscous liquids can lead to problems regarding the smelting of charged material or metal inclusions. This...

The consumption of lithium has increased dramatically in recent years. This can be primarily attributed to its use in lithium-ion batteries for the operation of hybrid and electric vehicles. Due to its specific properties, lithium will also continue to be an indispensable key component for rechargeable batteries in the next decades. An average lith...

A thermodynamic model, based on SimuSage, was developed to simulate refractory corrosion between a magnesia-based refractory material and ferronickel (FeNi) slags. The model considers a theoretical cross-section of a refractory material to simulate a ferronickel smelter application. The current model is structured into 10 zones, which characterize...

The recyclingRecycling of cemented carbidesCemented carbide at the end of their product life cycle is of particular economic, ecological and strategic importance. These composite materials, mainly consisting of tungstenTungsten carbide embedded in a Co binder, can be recycled by the so-called zinc processZinc process. This research investigates the...

The separation of cobalt and nickel from sulfatic leach liquors of spent lithium-ion batteries is described in this paper. In addition to the base metals (e.g., cobalt and nickel), components such as manganese and lithium are also present in such leach liquors. The co-precipitation of these contaminants can be prevented during leach liquor processi...

The quantities of cobalt and nickel ores mined annually increased in recent years due to their use in batteries. In addition, there is a great potential for substitution due to the diversity of the methods used and the high energy and raw material inputs of these processes. An alternative feedstock for the production of a nickel-cobalt alloy from h...

The influence of W content on the Co(W)Zn system and the behavior of individual elements was investigated. Cobalt is a so-called critical element and is one of the main parts in hard metal products. Because of its toxicity, it requires special care in handling. Further optimization of hard metal recycling, especially by the zinc process, is needed...

The present article explains the potential of controlling the ORP (oxidation reduction potential) in order to selectively leach the binder metal (commonly cobalt) from an hard metal substrate in a 2.0 mol/L HCl. Based on literature, corrosion investigations of cemented carbides reveal the chance of a parameter area, where just the cobalt is extract...

The selective recovery of valuable metals from metal-containing residues not only conserves the primary resources, but also improves the availability of raw materials. First and foremost, the focus must be kept on previously not recycled wastes as these have been removed from the circular resource flow. The recycling of used batteries effects not o...

The ability of batteries to store energy is an indispensable feature for technical and consumer applications. Metal-containing residues from the battery industry can be processed in principle both pyro- and hydrometallurgical. However, in the pyrometallurgical route only the main metals are recovered, while valuable components such as e.g. rare ear...

Through process and technology development for the processing of complex residues with varying compositions in the field of metallurgy as well as a development of methods for the simultaneous multi-metal recovery from primary and secondary sources, an improvement of the raw material availability can be realized. Above all, previously not usable, me...

The production of synthetic tantalum concentrate (SynCon) from process residues, sludges or tin slags generates huge amounts of high melting slag, mostly comprising of Al2O3, CaO and SiO2. Metal/slag separation is a major criterion in the multi stage pyrometallurgical procedure to ensure product quality and yield, wherefore the flow properties of s...

The objective of this study was to develop an eco-friendly method for processing spent stripping solutions, which originate from the wet chemical decoating of metal cutting tools, to generate a product that represents a useful basis for the recovery of valuable components. These liquids contain, for example, considerable quantities of Ti, Co, and W...

At the moment the industrially applied techniques for cemented carbide reclamation feature several deficiencies. Depending on the process route, obstacles consist in high energy and chemical consumption (indirect recycling methods) or a deterioration of the recycled product in comparison with the primary material (direct recycling approach). Theref...

Waste electrical and electronic equipment (WEEE) and its recycling represents an essential issue in today's society. One possibility for the latter comprises a pyrometallurgical smelting, at which the output needs further converting. The option of a hydrometallurgical treatment of such an atomized (copper bearing) alloy was investigated, because of...

Influence of TiO2 concentration on the viscosity of SynCon slags: The production of synthetic tantalum concentrate (SynCon) in a multi stage pyrometallurgical process enables the use of various low grade input materials bearing at least a small Ta2O5 content. Thus, huge amounts of high melting slags accrue. For adequate product quality and process...

The metallurgical production of ferronickel in the electric arc furnace provokes large slag amounts with highly acidic character and high melting points, which heavily stresses the refractory material. This publication deals with the investigation of different slag mixtures regarding their melting behaviour, measured by a hot stage microscope. Ther...

The industrial manufacturing of ferronickel in electric furnaces produces large amounts of slag with strong acidic character and high melting points, which seriously stresses the furnace refractory. In this study, measurements by a hot stage microscope served for the determination of melting behaviour of synthetically produced ferronickel slags on...

Corrosion mechanisms between high melting synthetic ferronickel slags and refractory were investigated. The used slags were prepared by mixing and melting of specific oxides. Substrates of the applied refractory material and specimens of FeNi slags were heated in a hot stage microscope up to 1650 °C. The experiments were performed under a defined g...

A broad spectrum of tantalum containing input materials can be processed for the production of synthetic tan-talum concentrate (“SynCon”). The use of these low grade substances offers a secure alternative to mining of coltan in Central Africa. SynCon is produced in a multi-stage pyrometallurgical process, wherefore the melting behaviour of slags pr...

Interactions between high melting synthetic ferronickel slags with acidic character and MgO as refractory were investigated. In order to facilitate the complex composition of real ferronickel slag, a synthetic slag of SiO2-MgO-Fe2O3-CaO was used. The practical corrosion tests of the MgO refractory were performed in a hot-stage microscope at tempera...

The current work concerns the influence of different reduction conditions (temperature, dew point and hydrogen content as well as flow rate of reduction gas) on the morphology of molybdenum powder. The material was produced by a two-stage reduction of different sized molybdenum trioxide particles with hydrogen. The experiments were carried out in a...

This report aims to disclose interactions between semi-direct recycling concepts, corrosion analysis of hard metals and possible leaching mechanisms. Accordingly, an examination reveals chemical kinetic dependencies via leaching a cutting insert in formic acid inclusive an oxidant. Currently, contradictions and issues in literature slow down the pr...

Das Recycling von WC-Verbunden bietet eine Vielzahl an ökologischen, wirtschaftlichen und strategischen Vorteilen. Da Österreich den gesamten Produktlebenszyklus von Wolfram, dem Ausgangstoff für Wolframkarbid (WC), von Bergbau, Herstellung sowie Aufarbeitung der anfallenden sekundären Materialen abdeckt, hat diese Thematik einen entsprechend hohen...

Corrosion mechanisms have been investigated between MgO refractory substrates and synthetic FeNi slags. The materials taken into consideration comprised a simple synthetically mixed slag with specific oxides of slags from a ferroalloy producer. The MgO refractory substrates with the slag specimens on it were heated in a hot stage microscope to two...

The purpose of this investigation is to provide a basis for the semidirect recycling of hard metals. Accordingly, the present investigation focuses on revealing the fundamental chemical kinetic aspects during cemented carbide leaching in hydrochloric acid including an oxidant. In contrast to literature, the experiments are performed with pieces of...

The polishing of glass substrates or wafers requires fine-grained particles, frequently based on oxides of the lanthanides cerium and lanthanum. During processing the slurries become enriched with different elements depending on the specific production program and the chemical composition of the work piece. Concentrations of these impurities can re...

Corrosion mechanisms between MgO refractory substrates and FeNi slags were investigated. The FeNi slags taken into consideration represent a simple synthetically mixed slag with specific oxides and a real slag from a ferroalloy producer. The MgO refractory substrates with the specimens of FeNi slag were heated in a hot-stage microscope at 10 K/min...

The industrial manufacturing of ferronickel in electric furnaces produces large amounts of slag with strong acidic character and high melting points, which seriously stresses the furnace refractory lining. In this study, the melting behavior of synthetically produced ferronickel slags on magnesia as refractory material was determined by means of a...

The use of critical raw materials also increases due to the higher demand on electrical and electronic equipment (EEE). The high content of valuable substances in EEE in relation to primary ores secures a potential for its use as new raw materials sources, the so-called ‘urban mining’. Positive effects of urban mining are to save existing mineral r...

Refractory linings in pyrometallurgical furnaces are attacked by various process phases (e.g. metal, slag, gas). However, refractories are the barrier between these phases and the environment: refractory damages and consequent furnace failure can cause severe damages including potential danger for workers/operators. Hence, refractory corrosion and...

Due to the fact, that the need for technological metals for any kinds of electrical and electronic devices is increasing, proper recycling processes are crucial. Recycling protects the environment and regains a variety of substances and elements, such as metals. The challenge lies in the complexity and diversity of waste electrical and electronic e...

The increasing consumption of electric and electronic equipment has led to a rise in toxic waste. To recover the metal fraction, a separation of the organic components is necessary because harmful substances such as chlorine, fluorine and bromine cause ecological damage, for example in the form of dioxins and furans at temperature above 400 °C. Hen...

Für die 14 kritischen Rohstoffe nach COM (2011) 25 final [Europäische Union, 2011b] bzw. nach der Ausschreibungsgrundlage des bmvit (Kritische Rohstoffe und Potentiell Kritische Rohstoffe mit Bezug zu Österreich) ist im Wesentlichen bekannt, in welchen Anwendungen und Produktgruppen sie heute eingesetzt werden. Jedoch ist mit wenigen Ausnahmen nich...

Resources and energy have an essential importance for the industrial development in Europe. Especially the relevance of recycling processes will increase, which means that the life cycle of a product has to be considered. Therefore an intensive interaction of raw material technology, metallurgy, and material science will be necessary in the future....

In order to develop an industrial-size recycling process for new materials, which are designed to satisfy the ever-changing demands of technological innovation, the conversion properties have to be thoroughly studied. The complex conversion of a molybdenum-tantalum alloy as well as a tungsten-rhenium alloy is fitted to two different theoretical app...

The use of rare earth magnets increases in the past twenty years, because of their high performance in combination with the extensive application area. Therefore the need of critical raw materials like light and heavy rare earths is enhancing to achieve more performance. The supply risk of these ele-ments from primary producers turns into a dramati...

The use of rare earth magnets increases in the past twenty years, because of their high performance in combination with the extensive application area. Therefore the need of critical raw materials like light and heavy rare earths is enhancing to achieve more performance. The supply risk of these ele-ments from primary producers turns into a dramati...

Available online (full-text): http://www.vivis.de/index.php?option=com_content&view=article&id=314:recycling-und-rohstoffe-band-8&catid=54:recycling-und-rohstoffe&Itemid=76

Raw materials are very essential for the economy and subsequently for the modern society. They are required for industrial activities as well as for infrastructure and products used in everyday life. The importance of oil, gas, and coal has often been mentioned since the oil crises in the 1970s that lead to sharp price increases. However, the impor...

In general, a printed circuit board (PCB) consists of about 28 % metals, 23 % plastics, and 49 % ceramic components. This diploma thesis, written at the Chair of Nonferrous Metals, addresses the separation of plastics under the condition of an inert atmosphere for the removal of dangerous components, like flame retardand elements, such as bromine,...

The use of critical raw materials also increases due to the higher demand on electrical and electronic equipment (EEE). The European Union defined a list of 14 critical raw materials, where some of these metals are included in waste electrical and electronic equipment (WEEE). The high content of valuable substances in electrical and electronic equi...

Eine typische Leiterplatte besteht aus zirka 28 % Metallen, 23 % Kunststoffen und 49 % keramischen Bestandteilen. Die Diplomarbeit am Lehrstuhl für Nichteisenmetallurgie beschäftigt sich daher unter anderem mit der Abtrennung der Kunststoffe in einer inerten Atmosphäre, um gefährliche Bestandteile wie flammhemmende Elemente, z.B. Brom, in einem Was...

The higher consumption of modern equipment, especially personal computers and laptops, increases the production of hard disc drives. For the positioning of the actuator arm rare earths magnets are necessary, which contains neodymium, iron, boron and some other REE. Due to the high risk for the procurement of these metals many investigations for eff...

The higher consumption of modern equipment, especially personal computers and laptops, increases the production of hard disc drives. For the positioning of the actuator arm rare earths magnets are necessary, which contains neodymium, iron, boron and some other REE. Due to the high risk for the procurement of these metals many investigations for eff...

NE -Metalle: Computerfestplatten sind ein Eldorado für das Aluminiumrecycling. Am Lehrstuhl für Nichteisenmetallurgie an der Montanuniversität Leoben wird an einem optimalen Recyclingkonzept geforscht.

Die Nachfrage an moderne Medien wie PCs und Laptops steigt stetig an und somit auch die Produktion von magnetbasierenden Speichermedien. Diese nutzen zum Betätigen der Schreib- und Leseköpfen eine seltenerdhaltige Verbindung aus Neodym, Eisen und Bor. Des Weiteren werden noch diverse andere SE-Elemente zur Eigenschaftsoptimierung hinzugefügt. Durch...

Cerium dioxide is frequently used as an abrasive material in the glass industry. The field of application includes the technique of CMP (chemo-mechanical polishing/planarization) which is also used for wafer processing in semiconductor production. The aim of this work was the development of a process for the recovery of cerium and lanthanum from a...

The higher demand for electrical and electronic equipment (EEE) has led to an increased usage of indium, gallium and germanium. The European Union declared these raw materials as critical, because of supply risks and their high economic significance. The most important application of indium is in the display technology for the electrodes made of in...

Tantalum and niobium are two outstanding elements of technological metals. Their applications are widespread and the substitution is only possible in few cases. Europe has no primary mining of the two chemical related elements, so the domestic industry is forced to process secondary raw materials in order to diminish dependencies on foreign raw mat...

Rare earth (RE) containing materials currently provide the strongest permanent magnets. They consist mainly of intermetallic compounds of samarium, neodymium and transition metals like iron or cobalt. About 20 % of the worldwide production of RE is used for the fabrication of magnets (SmCo, NdFeB) and approximately 97 % of the global extraction of...

The main application areas for the rare earth elements are amongst others phosphors in different types of lamps, alloys for hydrogen storage in rechargeable batteries, catalysts, materials for permanent magnets and various ceramics. Furthermore, these metals are of great importance in the glass industry not only for the coloration and discoloration...

The fields of application for rare earth elements (REE) are nowadays wide spread. They are mainly used for permanent magnets, catalysts, hydrogen storage alloys for rechargeable batteries, glasses, ceramics and polishing agents. Moreover these elements are needed for the production of phosphors used in different types of lamps (fluorescent tubes, e...

Die Effizienz des Recyclings von Elektronikschrott ist durch mehrere Faktoren geprägt. Im Falle der Wiedergewinnung von Seltenen Erden aus Festplatten treten die größten Verluste im Bereich der Aufbereitung auf, da diese aufgrund des magnetischen Verhaltens durch Fehlwürfe ausgeschleust werden und so keinerlei Verwertung erfahren. Das am Lehrstuhl...

In der industrialisierten Welt nehmen heutzutage die Technologiemetalle trotz ihrer im Vergleich zu den Massenmetallen geringen Produktionsmengen eine zentrale Position ein, da sie für zahlreiche Anwendungen unverzichtbar sind. Während diese bis vor einigen Jahren kostengünstig am Weltmarkt in ausreichenden Mengen verfügbar waren, traten in letzter...

The development of an efficient and stable blue GaInN-semiconductor exhibited a breakthrough for the application of light emitting diodes. The following technological development and the ban of light bulbs currently cause a rapid change in the lighting technology. On the one hand the light bulbs, which were used to a large extent, disappear from th...

The RFID technology (Radio Frequency Identification) represents an extensive field of application for logistic topics.. The application of RFIDs is unlimited. Particularly the simple replacement of the established bar-code system by smart labels and also the tracking/tracing of various objects, animals and people exhibit a high market potential. Du...

It is possible to extract rare earth compounds out of used nickel-metal-hydride batteries by a hydrometallurgical treatment. During this process a high amount of spent acid which still contains various valuable metals is produced. produced. To remove metals from an aqueous solution many different ways such as electrolysis, precipitation, crystallis...

In the area of slags phase diagrams, such as ternary systems provide support in pyrometallurgical processes. Low viscosities and liquidus temperatures in addition addition to high reactivities are often required for an economic production. In ternary systems refractory metal components are problematic due to the availability of thermodynamic data o...

The so-called technological metals (rare earths, refractory and precious metals, etc.) are of enormous importance for today's world, because they are essential for the manufacture of many products. However, the price development for rare earths over the last two years has shown that the supply of raw materials for these elements is not ensured. In...

The developed process for the recovery of tungsten scrap, especial hard metal soft scrap that is submitted for a patent, can be classified as an indirect recycling process. The main process steps of this recycling process are the pretreatment of the scrap, the pyrolysis, the acidic extraction of binder metal, the roasting, the ammoniacal leaching o...

The indirect reprocessing methods which transform the binder metals and the metal carbides into new chemical compounds are able to produce high quality end products. The developed recycling technologies mainly use a combination of pyro- and hydrometallurgical or chemical techniques. Aerial oxygen, oxygenic salts or electricity are used as oxidation...

Abstract The behaviour of different materials at increasing temperatures, especially the melting, is determinable by various methods. The information from technical literature, thermodynamical calculations by FactSage and practical measurements by a heating microscope are compared for the system Cr2O3–FeOx–ZnO, which is essential for EAF dusts. The...

Lithium has the lowest density of all metals (p = 0.534 g/cm3). It was discovered more than 200 years ago in minerals. The first use of lithium on an industrial scale started after WWI in the so-called "Bahnmetall, " a lithium-containing lead alloy for slide bearings. Further areas of applications followed during the last 50 years, for example, the...

Nickel metal hydride batteries (NiMH batteries) are mainly used for applications with extensive power requirements, such as toys, remote controls, power tools, audio-, photo-, and video equipment and even electric as well as hybrid vehicles. These cells consist of about 6 to 10 % rare earths (RE) such as La, Ce, Nd and Pr in addition to various oth...

Besides its use in superconducting materials, niobium has several other areas of application in the form of pure metal, alloys, intermetallics and other compounds. Some of them require niobium powders as a raw material, such as the fabrication of electrolytic capacitors. Because the element niobium has all desired properties as an anode material of...

Red mud is a solid by-product of bauxite processing via the Bayer process and consists mainly of Fe2O3, Al2O3, Na2O, SiO2 and TiO2. Minor or trace elements in this material can be K, Cr, V, Ni, Ba, Cu, Mn, Pb, Zn, Zr, Y, Sc, Ga etc. and even the radioactive U and Th. Currently, about 90 million tonnes of this highly alkaline waste material with pH...

In recent years the recycling of refractory metals has become more important. Specific reasons for this trend are local scarcities of raw materials because of remote deposits and the economic incentive of secondary metallurgy. At present there is generally no lack of supply of refractory metals like vanadium, nickel and molybdenum in the sector of...

Due to the protection of the resources the whole metallurgy is forced to recover metals out of waste materials. In this case also the refractory metals like tungsten had to be recycled. Tungsten is a raw material in quite different industries but mainly it is used for the production of hard metal. By the machining of this basic material and after t...

Hard metal scrap is produced at the fabrication of hard metal components. This waste material is subdivided into lumpy residues (hard scrap) and fine particles, powder, dust, sludges and unsintered pieces (soft scrap). Due to availability of resources it is necessary to treat and recycle these materials with appropriate techniques. According to scr...

Hard metal scrap is produced at the fabrication of hard metal components, which is subdivided into hard scrap (lumpy scrap) and soft scrap (e.g. powder, sludges and unsintered pieces). For economical and environmental means it is necessary to treat and recycle this scrap with appropriate techniques. According to type, quality and purity tungsten co...

Während Tantalpulver bereits seit Jahrzehnten erfolgreich zur Produktion von Kondensatoren Verwendung findet, konnte sich Niob trotz seiner chemischen als auch zum Teil physikalischen Ähnlichkeit lange Zeit nicht durchsetzen. Eine Preisexplosion für Tantalit-Konzentrat im Jahr 2000 verstärkte jedoch die Anstrengungen, Tantal durch das kostengünstig...

Im Vergleich zu den anderen Reduktionsmitteln weist Wasserstoff einige Vorteile auf. So ermöglicht dieser die Herstellung sehr reiner Metalle durch Reduktion der jeweiligen Oxide und ist auch im Hinblick auf die Reduktionszeit vorteilhaft. Die Veröffentlichungen der letzten Jahre weisen weiters darauf hin, dass Wasserstoff auch zur Herstellung eine...

Zusammenfassung Die Verarbeitung eisen-haltiger Schlacken mit niedrigem Vanadiumgehalt durch pyro metallurgische Verfahren ist eine Möglichkeit für die gemeinsame Herstellung von Ferro vanadium-Legierungen und einer verkaufsfähigen Schlacke für die Bauindustrie. Neben thermodynamischen Berechnungen erfolgte die Durchführung unterschiedlicher Experi...

At the production of ferroalloys, slag includes large quantities of vanadium. In order to understand the activity of vanadium during the process, it is of great importance to know the oxidation behaviour. This article deals with the influence of the dwell time and the composition of slag on the oxidation state of vanadium. Furthermore vanadium bear...

The refractory metals niobium, tantalum, molybdenum and tungsten as well as their alloys, intermetallic and other compounds plus the derived composites exhibit outstanding properties and are therefore widely spread in the industrialized world. Some of their areas of application, where refractory metals could not be easily replaced by other substanc...