The recovery of critical elements in recycling processes of complex high-tech products is often limited when applying only mechanical separation methods. A possible route is the pyrometallurgical processing that allows transferring of important critical elements into an alloy melt. Chemical rather ignoble elements will report in slag or dust. Valuable ignoble elements such as lithium should be recovered out of that material stream. A novel approach to accomplish this is enrichment in engineered artificial minerals (EnAM). An application with a high potential for resource efficient solutions is the pyrometallurgical processing of Li ion batteries. Starting from comparatively simple slag compositions such as the Li-Al-Si-Ca-O system, the next level of complexity is reached when adding Mg, derived from slag builders or other sources. Every additional component will change the distribution of Li between the compounds generated in the slag. Investigations with powder X-Ray diffraction (PXRD) and electron probe microanalysis (EPMA) of solidified melt of the five-compound system Li₂O-MgO-Al₂O₃- SiO₂-CaO reveal that Li can occur in various compounds from beginning to the end of the crystallization. Among these compounds are Li_1−x(Al_1−xSi_x)O₂, Li_1−xMg_y(Al)(Al_3/2y+xSi_2−x−3/2y)O₆, solid solutions of Mg_1−(3/2y)Al_2+yO₄/LiAl₅O₈ and Ca-alumosilicate (melilite). There are indications of segregation processes of Al-rich and Si(Ca)-rich melts. The experimental results were compared with solidification curves via thermodynamic calculations of the systems MgO-Al₂O₃ and Li₂O-SiO₂-Al₂O₃.

Outstanding electroactive properties of certain crystallographic phases of poly(vinylidene fluoride) (PVDF) bring much attention to its melting and crystallisation behaviour for tailoring crystallographic nature. In the past, the focus was put on operating conditions in terms of melting and crystallisation kinetics, whereas a deeper understanding of the molecular structure–property relationship of PVDF is sparsely addressed. This study is the first survey to investigate systematically the structure–property relationship by clarifying the question, how molecular weight distribution affects thermal–caloric properties and hence polymorphous phase behaviour. It is shown that molecular weight strongly influences electroactive phase formation and plays a key role in phase design. GRAPHICAL ABSTRACT IMPACT STATEMENT This work provides new insights in molecular weight induced electroactive phase formation in poly(vinylidene fluoride)

Ultrasonic degradation of polymers attracts more and more attention in the field of chemical recycling of polymers due to the promising opportunity to tailor molecular weight and polydispersity of the gained polymer fragments. In this work, the influence of solvent, gas atmosphere, and ultrasound amplitude on the ultrasonic degradation process of polystyrene is investigated. Therefore, an experimental procedure to perform ultrasonic degradation of polystyrene under homogeneous temperature conditions in the solvents cyclohexane and toluene under the gas atmospheres CO₂ and N₂ for different ultrasonic amplitudes was designed. It could be shown that a significant effect on the molecular weight and polydispersity of the polymer could only be revealed for N₂ and not for CO₂ atmosphere.