4 Material und Umwelt
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- 4 Material und Umwelt (440)
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Tantalum and niobium are essential for the development of electronics towards a more and more compact design, but without reducing their performance today. Especially in smart phones and tablets, tantalum and niobium capacitors with high charge densities have already become almost indispensable. However, tantalum as a critical raw material is still a problem for the sustainable production of electronics. Due to this fact, the existence of efficient recycling processes especially in Europe is becoming even more important nowadays.
The Bundesanstalt für Materialforschung und -prüfung (BAM) is currently working on the optimisation of an existing pyrometallurgical tantalum recycling process. Optimisation of this industrial process is carried out in a small-scale electric arc furnace (480 kVA, capacity approx. 150 kg/h) at BAM using a new and innovative equipment for on-line analysis of high temperature processes.
The aim of this project is to identify the best timing for an optimum slag tapping, when the slag is lower than minimum targeted tantalum concentration. Hence, LIBS (Laser induced breakdown spectroscopy) is used to identify the chemical composition of the slag layer and during slag tapping. The on-line-LIBS prototype of BAM enables an in-situ measurement of the element distribution in the melt after calibration on the slag system.
First results of this joint research project will be presented including on-line-LIBS-measurements and thermodynamic and kinetic aspects of the process.
Optimierung eines pyrometallurgischen Tantal- und Niob- Recyclingprozesses mithilfe von On-Line LIBS
(2018)
Die Entwicklung von Hochleistungselektronik zu immer kleineren Bauformen ohne Leistungseinbußen ist ohne den Einsatz von Technologiemetallen wie Niob und Tantal heute praktisch nicht mehr realisierbar. Besonders in technischen Geräten wie Smartphones und Tablets sind Tantal- und Niobkondensatoren aufgrund ihrer hohen Leistungsdichten bereits unverzichtbar geworden. Für die nachhaltige Produktion von Elektronik stellt jedoch vor allem das Tantalerz Coltan als sogenanntes „conflict mineral” ein großes Problem dar.
Um den Wirtschaftsstandort Europa unabhängiger von Primärrohstoffimporten aus Krisenregionen zu machen, ist die Entwicklung von effizienten Recyclingverfahren heute wichtiger denn je. An der Bundesanstalt für Materialforschung und -prüfung (BAM) findet daher zurzeit die Optimierung eines pyrometallurgischen Industrieprozesses zur Niob- und Tantalrückgewinnung statt, welchem hauptsächlich niedrigkonzentrierte metallurgische Rückstände aus der Tantal- und Niob- bzw. der Zinngewinnung als Einsatzstoffe dienen.
Zu diesem Zweck werden im kleintechnischen Lichtbogenofen der BAM (480 kVA, max. Materialdurchsatz ca. 150 kg/h) Versuche mit einem neuen innovativen Messgerät durchgeführt, welches eine On-Line Analyse von Hochtemperaturprozessen ermöglicht. Der eingesetzte Prototyp nutzt das Verfahren der laserinduzierten Plasmaspektroskopie (LIBS), um die chemische Zusammensetzung der Schlackephase noch im Schmelzbad und während eines Schlackeabgusses zu bestimmen. Nach einer Kalibrierung auf das vorliegende Stoffsystem ermöglicht dieser On-Line-LIBS Prototyp der BAM daher eine in-situ Bestimmung der Elementverteilung in der Schmelze. Die hier gewonnenen Daten sollen helfen, die aktuelle Prozessführung zu verbessern und die Tantal- und Niobausbeute noch weiter zu erhöhen.
Two new approaches towards an emission reference material for use in quality assurance measures for materials emissions testing were developed and intensively tested. The overall goal was to obtain solid materials with homogenous and reproducible (S)VOC release. Since the application in inter-laboratory comparisons is aimed at, it should furthermore be long-term stable to ensure safe shipment to the customer without sustaining compound losses. In the first approach, thermoplastic polyurethane (TPU) was impregnated with the VOC texanol under high-pressure with liquid CO2 as solvent. In the second, styrene (VOC) and the SVOC 2,6-diisopropylnaphthalene (DIPN) were spiked into vacuum grease (VG) and a mixture of paraf-fin/squalane (P/S). For the prediction of the emission rates a finite element model (FEM) was developed for the VG and P/S type materials. All requirements for reference materials were fulfilled, whereas the TPU samples need to be aged for about 10 days until repeatable and reproducible emission rates were obtained.
A presentation held for the seminar "Ausgewählte analytische Methoden der Physik" hosted by Prof. Birgit Kanngießer at TU Berlin. The first part focus on depth-dependent XPS-measurements (XPS, synchrotron HAXPES) to obtain a concentration profile of iodine in an artificial biofilm. In the second part, NAP-XPS measurements of various bacterial samples are presented.
Z02 is one of the three technically supporting projects at the CSMC. In collaboration with Z01 and Z03, it aims at bridging the gap between humanities and natural sciences and technology. To that purpose, we set up a laboratory with a range of high-end instruments, most of them mobile, allowing thorough non-destructive analysis of manuscripts. In addition to working on constantly improving the laboratory and the methods of analysis, a substantial part of our activities is dedicated to service, by supporting different research projects conducted at the center.
In this talk, we will present our equipment and the possibilities offered by the different techniques available regarding the different kinds of missions: typology and classification of inks, provenance studies, recovery of faded inscriptions and palimpsests, reconstruction of the history of manuscripts, authentication and dating. We will give a brief overview of our past and ongoing activities in the frame of the second phase of the CSMC. Finally, a selection of three projects will be presented in greater detail to highlight the possibilities of our laboratory and the diversity of missions which can be carried out:
- Support of project C08 on East Frankish manuscripts containing collections of formulae
- Identifying color materials applied in Muhammad Juki's Shahnamah with non-invasive combined methods
- Checking for the presence of metals in the Herculaneum papyri
Recent studies have shown that host-microbiota interactions can lead to dramatic changes in host phenotype especially behaviour. We investigate the causal drivers of microbe-associated shifts in host phenotype by examining how feeding behaviour is modulated by a bacterial infection in an omnivorous cockroach: Blatta orientalis. We conducted food-choice experiments after challenging hosts with the common entomopathogenic soil bacterium Pseudomonas entomophila to understand the impact of bacterial pathogens on host macronutrient preference. We find that immune challenge by this bacterium drives a sharp decline in carbohydrate intake and results in a relative increase in the ratio of protein to carbohydrate consumed. Additionally, infected cockroaches reduce their overall nutrient intake. We show for the first time that cockroach feeding behaviour is dynamically modulated by a pathogen. In contrast to studies on Spodoptera moths, this modulation does not impact any of the immune parameters we measured: it does not affect the abundance of immune related proteins in the hemolymph, hemolymph antimicrobial activity, or survival. This leads to the possibility that as long-lived omnivorous species B. orientalis may be better adapted to unpredictable variation in food availability and quality. An illness-induced anorexia-like response which is thought to assist hosts in limiting nutritional resources available to pathogens is therefore the most likely cause of the observed phenotype. Reduction of carbohydrate intake by sick individuals would be consistent with such an explanation.
In another cockroach species Blatella germanica we also investigate whether in addition to pathogens, host microbiota especially gut commensals are causally responsible for shifts in host behavioural phenotype and immune competence. To address this, we conduct food-choice and immunechallenge experiments in germ-free cockroaches and naïve cockroaches.
Potential use of incineration bottom ash in construction – Evaluation of environmental impact
(2018)
Around 5 million tonnes of MSWI bottom ash (BA) are generated per year in Germany. The incineration itself serves for metals as a concentrating and cleaning process. However, due to the almost exclusive wet extraction out of the furnace chamber the various metals are integrated in a heterogeneous and instable matrix. The metal recovery is therefore still a challenge relating the recovery rate and the purity, respectively. With state of the art treatment trains in Germany around 7.7% of ferrous metals and 1.3% of non-ferrous metals can be recovered out of MSWI BA. Large quantities of the mineral fraction are reused for sub-base material in road construction. A three month ageing period has been established as the common practice of further treatment of bottom ash before reuse applications. In the course of this aging the pH value of bottom ash decreases and contaminants are immobilized by processes like carbonation, hydration and oxidation. In particular leaching of heavy metals may be reduced to environmentally acceptable levels. However, the aging results in fixing of other valuable resources such as metals. Two laboratory scale lysimeters (30 cm in diameter) are being operated for more than three years aiming at the investigation of the long-term leaching behavior of a 0.25/45 mm mineral material obtained by treatment of MSWI bottom ash directly after incineration by a wet processing technology. Artificial rainwater is used as leachant (pH ≈ 6, ingredients NO32-, Cl-, SO42-, Na+, K+, Ca2+, Mg2+). The lysimeters are irrigated related to an average annual precipitation rate of 600 mm/a leading to a liquid to solid ratio (L/S) of about 0.7 per year of operation. Lysimeter tests are more adequate to simulate field scenarios and long-term leaching behavior in contrast to laboratory column tests particularly due to the unsaturated conditions and realistic contact time with the leachant.
In comparison to the leaching of bottom ash (aged for 3 month and non-treated) in column tests the chloride and sulfate leaching in the lysimeters was reduced as a consequence of the previous wet processing. The sulfate release kept almost constant limited by CaSO4 solubility up to an L/S of about 0.7 l/kg. The chloride concentrations dropped quickly, starting from 7300 mg/l, and are now at an almost constant level of 50 mg/l which is significantly above the chloride concentration in the leachant. After an initial decrease of the pH from about 10.4 to 8 at L/S of 0.2 l/kg, the pH increased again and leveled out around 9.8 up to L/S 2.2 l/kg. At an L/S of about 2.5 l/kg now, Cr, Cu are still released. The Cu and Cr concentrations in the leachates were about 760 µg/l and 90 µg/l respectively at the beginning. For both metals the concentration decreased to about 35 µg/l now. The Mo concentrations dropped steadily from 1300 to 250 µg/l, whereas V and Sb concentrations increased in the course of the tests. Fe and Mn are not detectable anymore. More results of this experimental study will be presented and discussed with a special focus on elements forming oxyanions.
LD-Schlacken weisen eine große chemische Ähnlichkeit zu Protlandzementklinker auf. Sie enthalten jedoch noch bis zu 30% Eisen, das mineralisch in oxidischer Form gebunden vorliegt. Dadurch kann sich bei der Erstarrung die wichtigste Klinkerphase "Alit" nicht ausbilden.
Durch eine reduzierende Schmelzbehandlung der Schlacke kann des mineralisch gebundene Eisen als Metall separiert werden. Dadurch wird auch die Mineralogie der Schlacke so verändert, dass auch sie nun praktisch einem Portlandzementklinker entspricht.
Entsprechende Versuche wurden am kleintechnischen Lichtbogenofen der BAM durchgeführt. Es werden Ergebnisse vorgestellt und auf Grenzen und Möglichkeiten eines derartigen Prozesses im Hinblick auf eine industrielle Umsetzung eingegangen.
Die Präsentation erläutert die Hintergründe der nationalen Anforderungen für die Verwendung von Kunststoffdichtungbahnen in Deponieabdichtungen. Die Beständigkeit wird diskutiert. Anforderungen an das Qualitatsmanagement während der Produktion der Produkte und der Bauphase werden aufgezeigt und die Auswirkungen auf die langzeitige Funktionserfüllung werden beschrieben.
The properties of nanomaterials are influenced not only by their chemical composition but also by physical properties (such as size, geometry and crystal structure). For the reliable determination and assessment of behaviour and effects of nanomaterials as well as for the determination of the exposure of humans and environment a comprehensive physical-chemical characterization of nanomaterials is essential. This is an important prerequisite to identify them as nanomaterials and to interpret and compare test results and - in future – to forecast interaction and effects of nanomaterials.
In 2006, the OECD launched a sponsorship program for the testing of nanomaterials in which 11 nanomaterials were thoroughly investigated using a variety of methods. The aim of the project was, among other things, to find out where problems occur and where there are gaps in the measurement and test procedures and where are changes required. An important outcome of the sponsorship program was the finding that the OECD Test Guidelines should in several cases be extended to the specific needs in testing of nanomaterials. The existing standardized test methods of the OECD for physical-chemical characterization have not been developed for nanomaterials in particular. A high demand for an extension of the test guidelines was identified. Germany complied with the OECD's request in 2017 and has agreed to extend the “Test Guideline on Particle Size Distribution / Fiber Length and Diameter Distributions Test Guideline” for Manufactured Nanomaterials (MN). UBA commissioned BAM and BAuA with the preparation of the Test Guideline. The aim of the project is the development of a harmonized test protocol for a valid and reproducible determination of particle size and size distribution which is one of the most relevant physical-chemical properties for MNs.
Different measuring methods provide different results for the size distribution of the particles. This is caused by the different measuring principles of the methods. Each method measures a specific parameter that ultimately determines particle size. First, the measured quantity differs for each method (Scattered light intensity, 2D image / projection, electric mobility, etc.). Second, the calculated diameters of the MN may differ (Feret Diameter, Area Projection, Mobility Diameter, Aerodynamic Diameter, Hydrodynamic Diameter). Third, a measuring method provides a size distribution which is measured either mass-based, surface-based or number-based. A conversion between the results requires additional parameters and thus possibly increases the measurement error.
In addition to the technical differences, the individual parameters are strongly influenced by the structure and material of the nanoparticles. For example, a surface functionalization can lead to very different results in the size distribution. The suitability of measurement methods differs with the material of the MN. As a result, two very different results can be measured for the particle size distribution using two different methods, which are nevertheless both correct. Several large projects in recent years therefore concluded that nanomaterials should be characterized by at least two complementary method. Imaging techniques are regarded as one of these methods for the characterization, the complementary methods are supposed to be statistical methods.
The different results for the size distribution of nanomaterials become problematic for the registration of new MN. A comparable and reproducible size distribution is a prerequisite for a standardized registration. In the future, the particle size distribution in the EU will also decide on the classification of a substance as a nanomaterial or as a non-nanomaterial. Especially in borderline cases, a standardized and comparable measurement methodology is therefore essential.
Mit dem Fokus auf eine saubere Innenraumluft wird darauf eingegangen, welche Emissionen aus Materialien und Produkten es gibt und wie sie nach Art und Flüchtigkeit definiert sind und wie sie gemessen werden. Im weiteren wird dargestellt, was und wie viel aus Materialien und Produkten emittieren kann und wie die Emissionen zu bewerten sind. Hierbei wird auch auf besonders emissionsarme Materialien und Produkte eingegangen.
Direct and indirect effects (DIERec) of the recovery of secondary resources are in the range of 500 million tonnes per year in Germany; energy savings are 1.4 million TJ. These savings are between 10 and 20% of the total. The effects of materials recovery exceed those of energy recovery by far with the exception of secondary plastic material where DIERec from energy recovery is higher by factor of 2.7. Untapped potential for the recovery of secondary resources exist in the fine fraction of bottom ash from municipal solid waste incineration, mainly Cu and precious metals and in urban mining.
The production of secondary materials from waste materials requires, in most cases, significantly lower energy amounts than the primary material production of raw materials. Along with lower energy demand, the greenhouse gas emissions produced are also lower. The duty of a modern waste management system should therefore be to collect and sort the waste materials in a way that the highest amounts of single material fractions with the highest qualities can be generated. In this contribution, the greenhouse gas balances of the theoretical treatment of the household waste, if collected as mixed waste in sanitary landfills, in waste incineration plants, or in mechanical-biological treatment plants, are compared to the existing separate waste collection and treatment in Germany in 2014.
In der Berliner Sammlung "Manuscripta Americana" befinden sich Fragmente von Bilderhandschriften, die Alexander von Humboldt 1804 in Mexiko erwarb und der Königlichen Bibliothek schenkte. Die in der frühen Kolonialzeit hergestellten verschiedenartigen Codices waren damals schon nicht mehr an den Orten ihrer ursprünglichen Verwendung. Entsprechend ihres Seltenheitswertes gelangten einzelne Schriftstücke seit der Conquista in die Bestände bedeutender Persönlichkeiten. Hierzu fertigte man auch Abschriften oder Kopien an, oder zerstückelte sogar einzelne Blätter, so dass die Darstellungen auf den abgetrennten Fragmenten oft nur zum Teil abgebildet vorliegen.
Um herauszufinden, ob einige Schriftstücke der "Humboldt Codices" in Bezug zu einander stehen, werden die Dokumente, ihre Symbole und Schriftzeichen und das zur Herstellung verwendete Material miteinander verglichen.
Mit den für die Analyse von Manuskripten bewährten Untersuchungsmethoden werden Papier und Farbmittel identifiziert. Hierzu zählen Raman-, FTIR-, Röntgenfluoreszenz- und VIS- Spektroskopie. Charakteristisch für die Herstellung von schriftlichen Dokumenten in der Kolonialzeit von Amerika ist die Verwendung von indigenem Material wie Papier aus Baumrinde und Pflanzenfarben zusammen mit den aus Europa bekannten Materialien. Geklärt wird, inwieweit neben den bekanntesten Farbstoffen wie Cochenille, Mayablau oder Mischungen mit Tonmineralen auch mineralische Pigmente zum Einsatz kamen.
Vorgestellt werden die auf Tafel 36 in den "Vues des Cordillères et Monuments des Peuples Indigènes de l`Amerique, Voyage de Humboldt et Bonpland" abgebildeten Fragmente. Die hier von Humboldt vorgenommene Zusammenstellung wird mit der Farbpalette der in Berlin archivierten originalen Schriftstücke verglichen. Die Interpretation der Ergebnisse gibt einen Hinweis auf die Zuordnung oder auch Zusammengehörigkeit dieser einzigartigen Dokumente amerikanischer Geschichte. Hierbei wird die Frage aufgeworfen, inwiefern davon auszugehen ist, dass diese mit weiteren Fragmenten in Verbindung gebracht werden können, was für die Beleuchtung der kulturhistorischen Zusammenhänge von großer Bedeutung ist.
Im Vortrag werden Auswaschversuche mit Bauprodukten vorgestellt, die dazu dienen sollen, Bauprodukte mit geringer Auswaschung zu erkennen. Zu verschiedenen Bauprodukten (Lacke für Außenanwendungen, Wärmedämmverbundsystemen, Dachziegel und Dachfolien) werden ausgewählte Ergebnisse vorgestellt. Die Eignung der Auswaschverfahren und die Testergebnisse werden bewertet.