Practical trainings, student assistants and theses

Nowadays, the processing of secondary resources is becoming more and more important as there is a high demand of critical raw materials. Especially batteries have high amounts of the critical metals Lithium, Cobalt, Manganese and Nickel as oxides used for cathode materials, as well as graphite, which is typically used as anode material. After comminution, these valuable minerals enrich in the fine fraction < 1 mm, which is called black mass. Studies have shown that froth flotation is a suitable technique to separate graphite from the cathode active materials.
In the course of the thesis, the separation of the cathode active materials, i.e. nickel-manganese-cobalt oxides, and the anode material graphite by flotation is investigated, with special focus on the influence of ultrasonication. Flotation tests will be carried out in an Outotec GTK lab cell. The flotation cell is modified in a way that ultrasound (by means of ultrasonication) can be applied during flotation. Therefore, a suitable reagent regime and process parameters for the flotation of black mass have to be established, followed by the development of suitable parameters for ultrasound treatment for this novel cell. Additionally, ultrasound will be tested in a pre-processing step before flotation as an alternative to attritioning by means of intensive shearing. Black mass from real spent lithium-ion batteries that was formerly processed via electrohydraulic fragmentation will be used for the tests. Analysis of the flotation products is done using thermogravimetric analysis and elemental analysis.

• Field of study in process, mechanical or chemical engineering or similar
• Interest in experimental investigation
• Good written and oral communication skills in English
• Please upload a short letter of motivation stating the period of time and your current grade overview to the applicant portal

• Student thesis
• Start date: by arrangement
• We offer an innovative multidisciplinary international research environment with relevance to key issues in resource technology

• Work inside an existing project for investigating and simulating strongly correlated quantum systems.
• Extend an already established method based on tensor networks to other fermonic and spin systems.
• Perform your own numerical calculations and evaluate the resulting data.
• Summarize the results and publish them in a paper and/or present them at a conference.

• Enrolment in physics, chemistry, computer science or a related field
• Interest, enthusiasm and ability to work independently and systematically
• Basic programming skills in Python and first experiences in HPC computing
• Knowledge of the basics of quantum physics and numerical methods
• First experiences in quantum many-body physics and numerical methods for quantum many-body physics desirable

• Working in an international team
• Compensation as a student research assistant (working hours to be agreed)
• Remote work possible; occasional on-site work would be beneficial
• Supervision within an interdisciplinary early-career research group
• Flexible starting date by agreement

The old smelting activities in different regions in Germany generated large quantities of metallurgical and mining residues containing significant concentrations of valuable metals. In recent days, the contaminated surface water from these residues is treated at a wastewater treatment plant by lime precipitation. During the treatment process, dissolved heavy metals such as zinc, iron, copper, nickel, and cadmium are removed by chemical precipitation using calcium hydroxide. The generated sludge has been dewatered using a chamber filter press and is currently disposed of as a landfill. Recent investigations have demonstrated that these wastewater treatment precipitates contain a considerable of valuable metals, and it represents a promising secondary raw material for the recovery of valuable metals, especially zinc.
The objective of the proposed master thesis is to develop a hydrometallurgical process for the selective recovery of zinc from the wastewater treatment precipitates. The work will investigate selective acid leaching conditions to dissolve zinc while minimizing the dissolution of calcium, magnesium and silicon. Subsequently, the pregnant leach solution will be purified through selective precipitation of metals other than zinc by pH adjustment. After purification, high-purity metallic zinc will be recovered by electrowinning. Furthermore, the calcium-rich leaching residue will be characterized thoroughly in order to evaluate its potential for industrial applications. The process wastewater generated during the metal recovery process will be treated with membrane purification studies, contributing towards a circular economy approach.

• Conduct literature research on the recovery of zinc, calcium, and other metals through Hydro metallurgic process as well as water treatment processes through membrane technologies
• Characterization and understanding of the feed materials using various techniques, XRD, FTIR, ICPOES, XRF, etc. before and after the experimental process
• Optimize experimental conditions for high recovery rates for zinc and other valuable metals
• Design and carry out laboratory experiments with selected nanofiltration membranes, focusing on variables like pressure, pH, and concentration
• Prepare a comprehensive thesis report and, if possible, present findings at relevant conferences or workshops

• Bachelor's degree in Chemistry, Chemical Engineering, Environmental Engineering or related field
• Knowledge of hydrometallurgical methods such as Leaching, precipitation, solvent extraction, and membrane technologies
• Knowledge of analytical techniques such as ICP-OES, AAS,MS or similar for metal concentration analysis
• Good oral and written communication skills in English
• Ability to work independently and systematically
• Duration: 6 months
• Start Date: Start in September 2026 is possible
• Funding: Remuneration according to HZDR internal regulations

Transparent conductive oxides (TCOs) are essential components for many everyday applications and devices, such as displays, smart windows, area lighting, flexible electronics, and solar modules. The most commonly used TCO is tin-doped indium oxide (ITO). In order to reduce the demand for the critical raw material indium, zinc oxide-based TCOs often represent a good alternative. However, ZnO is not suitable for applications involving high temperatures or aggressive environments. Tin oxide, SnO2, which exhibits the best thermal and chemical stability among known TCOs, offers a better alternative for applications in concentrated solar power, perovskite solar cells, and as electrodes in high-power electronics.
The most important functional properties of TCOs are high transparency in the visible wavelength range and high electrical conductivity. Both are strongly dependent on point and structural defects in the materials. Interestingly, these defects in SnO₂ are still not sufficiently characterized and understood, and are therefore the subject of ongoing scientific research. To improve the knowledge base of tin oxide-based TCOs, Bachelor's, Master's, or Diploma thesis topics are - among others - offered on the following sub-aspects:
1.) Identification of point defects of undoped Sn oxide thin films and correlation with the electrical properties
2.) Optimization of the electrical and optical properties of doped Sn oxide thin films
3.) Correlation of growth conditions and structural properties of tin oxide thin films
State-of-the-art in-situ and ex-situ methods such as magnetron sputtering, ellipsometry, UV-vis-NIR-FTIR and Raman spectroscopy, and X-ray diffraction will be employed.

• University enrollment in physics, chemistry, or materials science and good grades or better
• Interest, enthusiasm and ability for scientific work
• Basic programming skills and proficiency in using office and scientific software
• Fluent English language skills

• Payment includes the standard expense allowance

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.

Wir beschäftigen uns mit der Entwicklung von PET-Radiotracern, die Rezeptoren im Tumormikromilieu (TME = tumor microenvironment) für die Diagnostik und Therapie von Krebs sichtbar machen. Dazu werden geeignete tumoraffine Leitstrukturen identifiziert (niedermolekulare organische Moleküle, Peptide und Peptidomimetika), synthetisiert und mit einem geeigneten Radionuklid kovalent (z. B. Fluor-18, Iod-123) oder über einen Chelator (z. B. Gallium-68, Lutetium-177) markiert. Diese Radioliganden werden in vitro an Tumorzelllinien und in vivo im Tiermodell hinsichtlich einer Anwendung in der Nuklearmedizin getestet. Langfristiges Ziel ist die Translation der entwickelten Radiotracer in die Klinik als Diagnosewerkzeug (PET/CT) oder nach Markierung mit einem Beta- oder Alphastrahler für die Endoradiotherapie von Tumorerkrankungen.
Im Rahmen eines Studentenpraktikums oder einer Bachelor- oder Masterarbeit sollen organische Wirkstoffmoleküle synthetisiert und für eine anschließende radiochemische Markierung modifiziert werden. Die neuen Radioliganden werden dann biologisch in vitro und in vivo untersucht.

• Studium der Chemie
• Gute Noten in organischer Synthesechemie
• Fähigkeit sich in ein interdisziplinäres Wissenschaftler-Team einzugliedern
• Bereitschaft zum Umgang mit Radioaktivität
• Gute Kenntnisse der deutschen und englischen Sprache

• Beginn nach Absprache jederzeit möglich
• Praktikumsdauer mind. 4 Wochen, mit möglichst täglicher Anwesenheit

Tower power plants represent the latest generation of solar thermal power generation systems (see figure). Large-area mirror arrays concentrate sunlight onto a central absorber, where it is converted into thermal energy, which is then transferred to a heat transfer medium. Compared to photovoltaics, solar thermal energy has the inherent advantage of energy storage capacity and availability on demand. The challenge for further increasing the efficiency of solar power plants lies in developing materials with temperature stability up to 800 °C in air. Within the framework of graduate theses and research projects, thermally stable coatings for the core components of solar tower power plants will be developed and tested. State-of-the-art in-situ and ex-situ methods such as magnetron sputtering, ellipsometry, UV-vis-NIR-FTIR retroreflector, and Raman spectroscopy will be employed.
The following tasks are offered in this area:
i) Design and optical simulation of solar-selective coating stacks for solar power plants
ii) Deposition, optimization, and characterization of the structural, optical and electrical properties of individual components and whole coating stacks for solar power plants
iii) Ex situ and in situ investigations of the thermal stability of individual components and entire coating stacks for solar power plants
Other topics can be discussed individually.

1. University program in physics, chemistry, or materials science with good grades or better
2. Interest, enthusiasm, and ability for scientific work
3. Basic programming skills and proficiency in using office and scientific software
4. Fluent English language skills

This work is carried out in collaboration with national and international partners, payment includes the standard expense allowance