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. These valuable minerals enrich in the fine fraction < 1 mm, which is called black mass. Studies have shown that flotation is a suitable technique to separate graphite from the cathode active materials. Until now, the black mass is treated via flotation only and there has not been a combination of different separation techniques. Treatment of the black mass by means of turbulent cross-flow classification, either before or after flotation, could improve the separation result. Before the two processes can be combined, in a first step, the application of turbulent cross-flow classification on black mass needs to be investigated.
In the scope of this study, the student will investigate the separation behaviour of the black mass components during turbulent cross-flow classification. Special focus is placed on the influence of different particle properties such as sinking velocity (depending on size and density), as well as the influence of dispersants (e.g. sodium hexametaphosphate) and selective flocculants (e.g. polyacrylamide) and the use of high-power ultrasound for dispersion on the separation effect. Tests will be carried out using a Cyclosizer hydrocyclone cascade. Different feed materials will be used, such as non-pyrolysed and pyrolysed black mass from real spent lithium-ion batteries that underwent pre-processing via eleytrohydrolytic fragmentation, but also model compositions in order to better understand the separation process of such materials. The lab work not only includes the separation tests, but also the preparation and the analysis of the feed material and the products. To assess the separation outcome, analytical methods like elemental analysis, thermogravimetric analysis, mineral liberation analysis (SEM+EDX) and laser diffraction will be used.

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

• Student thesis, full-time if possible
• Start date: by arrangement
• Remuneration in accordance with HZDR internal regulations
• We offer an innovative multidisciplinary international research environment with relevance to key issues in resource technology
• The work will be performed at the Helmholtz Institute Freiberg for Resource Technology (HIF) in Freiberg