Practical trainings, student assistants and theses

X-ray fluorescence analysis (XRF) is a standard method to analyse a wide range of elements. Unfortunately, light elements (Z<11) are hard or impossible to analyse using XRF. On the other hand, LIBS (Laser induced breakdown spectroscopy) is able to analyse these elements. Especially the analysis of Lithium in solid samples is an urgent and currently needed topic. We aim to combine the two methods by developing an integrated workflow using fused beads, which is a standard technique for XRF sample preparation, for XRF analysis of the major elements and subsequent LIBS analysis for elements like e.g. Li.
Besides the development of a simple procedure to produce fused beads appropriate for both methods, calibration for both XRF and LIBS have to be implemented. The outcome of this (Master’s, Bachelor’s) thesis should be a as simple as possible workflow (including sample preparation), a sufficient number of reference materials (by e.g. mixing pure components), calibrations for XRF and LIBS, respectively and an evaluation of the desired method’s limitations. Motivated students of analytical chemistry, geosciences or adequate subjects are addressed.

Fine-grained solid particles from various industrial sources, which would otherwise be discarded, should ideally be processed to valuable products or inert residues. They contain valuable residuals, such as metals, that can be returned to the industrial cycle instead of being landfilled. This is one aim of the Helmholtz project FINEST in which this work is embedded.
The different finest powders need to be mixed and agglomerated for further processing. Our work in the project deals with the granular mixing. One aim is to describe the process using flow simulations in OpenFOAM.
The particle flow is described based on the rheology of the bulk material, while the mixing process between the particles is described using a transport equation. In addition, there are terms for the segregation that takes place in parallel.
We are looking for someone with experience in CFD or other modelling to refine the implementation of this model and then perform parameter studies and validation using experimental data.

• Student of e.g. Computational Engineering, Modelling and Simulation, Mechanical Engineering, Process Engineering, Chemical Engineering
• General interest in fluid mechanics and simulations
• Preliminary experience in CFD, ideally OpenFOAM
• Preliminary experience in code development (C++) optional

• Start from March 2025
• Duration of internship or thesis according to study regulations
• Remuneration available, scholarship holders (e.g. ERASMUS+) welcome

Focused ion beam induced deposition (FIBID) allows the high resolution 3D printing of insulating, conducting, semiconducting and superconducting nanostructures with nearly arbitrary shape. However, while being similar to focused electron beam induced deposition (FEBID) the physical processes are different enough that successful printing strategies from FEBID can not be transferred one to one to the FIBID process. FEBID 3D Algorithm for Stream File generation (F3AST) is a software package developed by our partners at the Vienna University of Technology (TU Wien) that has been successfully used to predict growth parameters for FEBID. The package is agnostic to the underlying charged particle technique and should be capable—potentially with some minor modifications—to also be used for the FIBID process.

The objective of this master thesis is to obtain calibration parameters for FIBID using the helium ion microscope (HIM). The HIM is a focused ion beam (FIB) technique that allows the imaging and fabrication of nanostructures with an optimum resolution in the sub-nanometer range. It utilizes a 0.5 nm wide focused beam of He ions to raster scan the surface. This beam of energetic (typically 10 keV to 30 keV) ions can be used for high resolution imaging and materials processing. After successful calibration of the model complex 3D nanostructures will be created to demonstrate the applicability of the
F3AST software for ion beam based 3D printing.

The researchers at the TU Wien will provide a modified version of the F3AST code able to generate input files for the FIBICS NPVE pattern generator. HIM and a W(CO)6 precursor gas will be used to grow simple 3D structures for the calibration of the software. HIM and scanning electron microscope (SEM) imaging will be used to obtain high resolution images of the nanostructures and extract the required geometrical parameters which will be feed to the F3AST software. Transmission electron microscope (TEM) investigations will be used to assess the composition of selected structures.
After successful completion of the calibration complex 3D structures will be grown and their fidelity will be qualitatively and where possible quantitatively evaluated.

Bachelor in Physics or Materials Science
Ability to work in a nanotechnology lab using delicate equipment
Ability to create simple scripts using python or similar languages
Presentation and office skills

You will be embedded in the ion induced nanostructures group (FWIZ-N) at the ion beam center (IBC) of the HZDR.

Platinum group metals (PGMs), particularly rhodium (Rh), palladium (Pd), and platinum (Pt), are regarded as the "vitamins" used in the modern industry. PGMs are crucial components of fuel cells, jewelry, computers, cell phones, automobile catalysts, etc. Their distinct physical and chemical characteristics, such as their corrosion resistance, chemical inertia, and catalytic activity, account for their extensive application and create alloys to enhance the characteristics of other transition metals. Because of their unique properties, PGMs are seldom replaced with other elements or compounds in applications. However, PGM deposits in the earth's crust are limited. The utilization of secondary resources, such as recycling waste materials, could mitigate the issue of PGM scarcity. Several conventional methods have been used for recovering PGM from secondary sources. Among the separation technologies, membrane separation offers the continuous and selective recovery of individual PGMs with no adverse environmental effects.
Supported liquid membranes (SLM) are a chemically driven membrane method in which a solvent phase contains an organic ligand that preferentially binds to a metal in the feed solution. The metal-ligand combination is subsequently diffusively carried across the membrane support and discharged into the receiving phase. This approach is particularly useful for metal ion separation because the organic carrier generates lipophilic metal-organic ligand complexes. This continuous permeation technique combines extraction and stripping procedures with less chemical reagents. The objective of the thesis work deals with the employment of task-specific organic ligands as carriers in the supported liquid membrane system for the selective recovery of platinum group metals from secondary source leachates and understanding the transport mechanism using different mathematical modeling approaches.

• Conduct literature research on supported liquid membranes using various organic carriers and their applications in metal recovery
• Design and conduct laboratory experiments using supported liquid membrane studies using task-specific organic carriers with several parameters such as pH, concentration, the thickness of membrane, feed solutions, etc.
• Analyse and interpret data on membrane selectivity, flux rates, fouling resistance, and metal recovery efficiency
• Optimize experimental conditions targeting high recovery rates for Platinum, Palladium, and Rhodium
• Prepare a thesis report and present findings at conferences or workshops

• Bachelor's degree in Chemistry, Chemical Engineering, Environmental Engineering or related field
• Knowledge of hydrometallurgical processes and membrane separation technologies
• Knowledge of analytical techniques such as ICP-OES, AAS, or similar for metal concentration analysis
• Duration: 6 months
• Start Date: Start in 2025 is possible
• Funding: Remuneration according to HZDR internal regulations

Understanding the behaviour of fibre-laden drops is critical due to their presence in various industrial applications, including microelectronics fabrication, portable medical devices, and biofuel production. Our work focuses on the numerical simulation of fibre-laden drops, specifically investigating a single long deformable fibre within a drop impacting a solid substrate. The study aims to elucidate the dynamic interactions between the fibre and the drop. Key objectives include determining the changes in drop dynamics due to the fibre and observing fibre deformation upon impact.

This work will involve computational fluid dynamics (CFD), particularly finite volume methods, with a focus on interface tracking using the Volume of Fluid approach. The simulation will incorporate surface wettability to enhance our understanding of elasto-capillary interactions, offering insights relevant to real-world applications.

We are seeking a motivated student with prior experience in CFD (preferably OpenFOAM) or similar modelling software.

• Enrolled in a degree program such as Process Engineering, Mechanical Engineering, or Computational Modelling and Simulation
• Strong interest in particle-fluid dynamics and numerical simulations
• Preliminary experience in CFD, ideally with OpenFOAM
• Basic coding skills, preferably in C++

• Immediate start possible
• Duration of internship or thesis as per university regulations
• Remuneration available, scholarship holders (e.g. ERASMUS+) are welcome

Vanadium and manganese are essential in high-strength steel alloys, battery technologies (notably vanadium redox flow batteries), and various chemical processes. Due to their industrial significance, recovering these metals from residual wash water along with leaching acids promotes environmental and economic sustainability. This study aims to Investigate and optimize a membrane filtration (nanofiltration) process for the selective recovery of vanadium and manganese, along with acid reclamation, from both acid raffinate and residue wash water solutions. The research evaluates the performance of various membranes focusing on their efficiency in concentrating vanadium and manganese while minimizing the co-permeation of iron, calcium, and other minor elements.
The objective of the work is to develop a process yielding a concentrated solution rich in vanadium and manganese for further precipitation, solid-liquid separation and hydrometallurgical steps, ultimately facilitating the recovery of vanadium as vanadium pentoxide (V₂O₅). The outcomes will offer valuable insights into the design and operation of membrane filtration systems for recovering critical metals and leaching agents from industrial effluents, supporting sustainable resource management practices in the metallurgical industry.
In addition to metal recovery, this research addresses acid reclamation following solvent extraction (SX) and supported liquid membrane process, with the goal of reducing chemical consumption. Acid recovery from the raffinate will be also explored, with organic contaminants removed via sorbents, such as activated charcoal. The reclaimed acid can then be recycled back into the leaching circuit, establishing a more sustainable process loop.

• Educational Background: Bachelor's / Master’s degree in Metallurgical Engineering, Chemical Engineering, Environmental Engineering or related field

• Knowledge of hydrometallurgical processes and membrane separation technologies
• Basic laboratory skills and familiarity with equipment for Nano filtration, filtration testing, and solution analysis
• Knowledge of analytical techniques such as ICP-MS, AAS, or similar for metal concentration analysis

• Conduct a literature review on nanofiltration technology and its application in metal and acid recovery
• Design and carry out laboratory experiments with selected nanofiltration membranes, focusing on variables like pressure, pH, and concentration
• Analyze and interpret data on membrane selectivity, flux rates, fouling resistance, and metal-acid recovery efficiency
• Optimize filtration conditions through experimentation, targeting high recovery rates for vanadium and manganese
• Prepare a comprehensive thesis report and, if possible, present findings at relevant conferences or workshops

• Duration: 6 months
• Start Date: Start in 2025 is possible
• Funding: Remuneration according to HZDR internal regulations
• Supervision and Support: The candidate (f/m/d) will be supervised with regular guidance, training on laboratory protocols, and support in analytical techniques

The development of a multi-channel flow body sensor according to patent WO 2010/069307 A1 aims to quantify the gas content in flow-carrying components. A decisive advantage of this sensor lies in its optical measuring principle, which is based on fiber-optic coupling and the analysis of the light output signal. This avoids electrical potentials in the measuring area, offering significant advantages over electrical measuring methods (intrinsic safety), especially for explosive mixtures.

Preliminary tests at the Institute for Experimental Fluid Dynamics at the Helmholtz Center Dresden-Rossendorf on gas-liquid flows showed that a clear binarization of the sensor output signal can be achieved due to the capillary effects in narrow channels and the different refractive indices of the gas and liquid phases. Building on previous work with a single-channel sensor prototype based on a polymer optical fiber (POF) with a diameter of 1 mm, the following tasks must be completed as part of further research.

Tasks:

• Adjusting the POF diameter to 1.5 mm in the single-channel configuration.
• Conducting experimental investigations of the new single-channel prototype using the already developed test system and evaluation programs.
• Designing a multi-channel sensor body for gas content measurements in the system.
• Developing a transition adapter to optimize the flow distribution between the DN10 flow pipe and the sensor body.

• Students majoring in fields such as process engineering, mechanical engineering, or chemical engineering.
• Interest in fluid mechanics and the development of measurement technology.
• Experience with 3D CAD tools.
• Basic knowledge of Python programming

Start date: 01.01.2025
Duration: according to the respective study regulations

1D- und 2D-Ramanspektroskopische Meßreihen oder auch Maps liefern detaillierte ortsaufgelöste chemische Informationen über die untersuchten Proben. Damit kann z. B. die Komponentenverteilung in Stoffgemischen quantitativ bestimmt oder die Homogenität einphasiger Proben gezeigt werden. Andererseits lassen sich lokale Strukturveränderungen, Spannungszustände, Stapelfolgenänderungen in 2D-Materialien und Punktdefekte charakterisieren. Voraussetzung dabei ist eine möglichst engmaschige Datenerfassung bis hin zur Auflösungsgrenze der verwendeten Laserstrahlung sowie eine große Anzahl an Messpunkten. Mit modernen Spektrometern sind Messzeiten im Sekundenbereich gut realisierbar. Die Umsetzung der spektroskopischen in eine chemische Information erfordert dann die Extraktion von Parametern wie Schwingungsfrequenz, Intensität und Linienbreite durch Spektrenanpassung. Die Gerätesoftware bietet dafür nur eingeschränkte Möglichkeiten.
Im Rahmen einer Graduierungsarbeit soll in Zusammenarbeit mit dem HZDR-Rechenzentrum ein Auswertealgorithmus für die automatisierte Auswertung von 1D- und 2D-Ramanspektroskopischen Meßreihen entwickelt, an Beispielen getestet und dokumentiert werden.

1. Studium der Werkstoffwissenschaften, Physik oder Chemie
2. Interesse, Freude und Befähigung für wissenschaftliche Arbeit
3. Grundkenntnisse in Programmierung und sicherer Umgang mit Büro- und wissenschaftlicher Software
4. Sehr gute Englisch-Kenntnisse

Die Arbeit ist in die umfangreichen Aktivitäten der Abteilung Nanoelektronik (FWIO) zu 2D-Werkstoffen eingebettet. Sie kann jederzeit aufgenommen werden.

Turmkraftwerke stellen die neueste Generation von Anlagen zur solarthermischen Elektroenergieerzeugung dar (s. Abbildung). Großflächige Spiegelanordnungen konzentrieren Sonnenlicht auf einen zentralen Absorber, wo es in Wärmeenergie umwandelt wird, die dann auf ein Wärmeträgermedium übertragen wird. Gegenüber der Photovoltaik hat die Solarthermie den inhärenten Vorteil, Energie zu speichern und bei Bedarf bereit zu stellen. Die Herausforderung für die weitere Erhöhung des Wirkungsgrades von Solarkraftwerken besteht in der Entwicklung von Werkstoffen mit einer Temperaturstabilität bis zu 800 °C an Luft.
Im Rahmen von Graduierungsarbeiten und Hilfstätigkeiten sollen thermisch stabile Beschichtungen für die Kernkomponenten von Solarturmkraftwerken entwickelt und getestet werden. Dabei kommen modernste in situ und ex situ Methoden wie Magnetronsputtern, Ellipsometrie, UV-vis-NIR-FTIR-Reflektometrie und Ramanspektroskopie zur Anwendung.
Zu diesem Themenbereich werden u. a. die folgenden Aufgabenstellungen angeboten:
i) Schichtabscheidung und Optimierung der optischen und elektrischen Eigenschaften von transparenten leitfähigen Oxiden für Solarkraftwerke;
ii) Entwicklung von neuartigen Absorber- und Wärmespeicherwerkstoffen für Solarkraftwerke;
iii) Design und Simulation von solarselektiven Beschichtungen für Solarkraftwerke.

Zur Charakterisierung der untersuchten Materialien stehen modernste in situ und ex situ Analysemethoden zur Verfügung. Die Arbeiten können jederzeit aufgenommen werden.

1. Studium der Werkstoffwissenschaften, Physik oder Chemie
2. Interesse, Freude und Befähigung für experimentelle wissenschaftliche Arbeit
3. Grundkenntnisse in Programmierung und sicherer Umgang mit Büro- und wissenschaftlicher Software
4. Sichere Englischsprachkenntnisse (fließend oder besser)

Internationale Forschungsumgebung, ortsübliche Aufwandsentschädigung