Wissenswertes zur Charakterisierung und Aufbereitung von Rohgrafiten

Abstract

Things to Know about Characterization and Beneficiation of Natural GraphitesAbstract: Making high-value products from natural graphite requires fine-tuned beneficiation processes. Both the type of graphite and the specialities in pricing of graphite products need to be considered during flowsheet development. This paper starts with an overview of the characterization of the different types of graphite, followed by the comminution, beneficiation and refining processes of natural graphite in general and with focus on flake graphite. The paper concludes with current research activities at the Chair of Mineral Processing at Montanuniversität Leoben in the field of natural graphite processing.Dipl.-Ing. W. Lämmerer ( )

Comminution and Classification as Important Process Steps for the Circular Production of Lithium Batteries

“…Normally, graphite exhibits a flake-like structure, consisting of multiple stacked layers of graphene with a large thickness in the horizontal direction (basal plane) and low thickness in the vertical direction (Lämmerer and Flachberger, 2017). By spheronization using a series of impact milling and classification process steps, the graphite morphology is modified to a more spherical shape, often referred to as "potato"-like shape (Asenbauer et al, 2020;Lämmerer and Flachberger, 2017).…”

“…This resulting structure, with a reduced specific surface area, leads to various benefits compared to the pristine graphite material, e.g. higher tap-density (Asenbauer et al, 2020;Kwon et al, 2021;Lämmerer and Flachberger, 2017), lower electrode tortuosity (Ebner et al, 2014;Müller et al, 2018) and increased energy density (Müller et al, 2018). Furthermore, the winding of the graphene layers during spheronization leads to more superficially localized edge planes, enabling new active sites at the surface for lithium ion intercalation.…”

“…Furthermore, the winding of the graphene layers during spheronization leads to more superficially localized edge planes, enabling new active sites at the surface for lithium ion intercalation. This facilitates faster ion transport and, thus, a higher rate capability and specific capacity for the spheronized graphite particles (Lämmerer and Flachberger, 2017;Natarajan et al, 2001;Wu et al, 2011). In addition to the reduction of specific surface area, spheronization also diminishes and narrows the particle size distribution, both enabling a better cell performance and preventing lithium plating (Bläubaum et al, 2020).…”

“…Consequently, the process parameters and stressing times have to be carefully selected for optimized particle design and cell performance. Moreover, the spheronization is often combined with subsequent carbon-coating, to further decrease the specific surface area and contact of the superficial edge planes with the electrolyte (Lämmerer and Flachberger, 2017).…”

Electric-impulse-technology: results of a basic investigation into the use of the technology as a selective demolition method in the construction industry

“…EIT can be used to economically pre-damage, remove and crush particularly hard materials, such as granite, ore or high-strength concrete, in drilling, processing and construction applications (Anders, 2021;Lämmerer, 2017;Lehmann, 2021;Voigt et al, 2017). The destructive effect is not based on the application of mechanical force, but on high-voltage pulses that are applied to the material via an electrode arrangement.…”