Multidimensional separation due to selective spherical agglomeration—Evidence of shape separation via X-ray microtomography--颗粒学报PARTICUOLOGY

Schreier, J., & Bröckel, U. (2021). Multidimensional separation due to selective spherical agglomeration—Evidence of shape separation via X-ray microtomography. Particuology, 58, 316-323. https://doi.org/10.1016/j.partic.2021.04.003

Multidimensional separation due to selective spherical agglomeration—Evidence of shape separation via X-ray microtomography

Julia Schreier ^*, Ulrich Bröckel

University of Applied Sciences Trier, Institute for Micro-Process-Engineering and Particle Technology (IMiP), Umwelt-Campus Birkenfeld, P.O. Box 1380, D-55761 Birkenfeld, Germany

10.1016/j.partic.2021.04.003

Volume 58, October 2021, Pages 316-323

Received 29 January 2021, Revised 26 March 2021, Accepted 5 April 2021, Available online 29 April 2021, Version of Record 18 May 2021.

E-mail: j.schreier@umwelt-campus.de

Highlights

• Multidimensional separation due to selective spherical agglomeration.

• X-ray microtomography (X-RMT) with graphite particles 1 μm–20 μm.

• Particle shape analysis with X-RMT images.

• Sphericity distribution of platelet and spherical graphite particles.

Abstract

Objective of this work was to develop a novel method for characterizing real 3D shapes of particles smaller than 20 μm by X-ray microtomography (X-RMT). Multidimensional separation of heterogenous solids through agglomeration in suspension will improve recycling processes as the particle shape and the agglomerate size are used for shape-selective separation. In the present paper we discuss the fundamentals of X-ray tomography and the experimental setup for selective spherical agglomeration in suspension. A specific preparation method of the particulate sample for X-RMT followed by 3D image processing, are essential for the shape analysis expressed as sphericity. We also discuss the limitation of this method due to the so-called Partial Volume Effect and particle clusters in the order of magnitude of X-RMT resolution. As proof of concept, we used a mixture of graphite platelets and spheronized graphite particles for a shape selective-agglomeration in suspension. The remaining fines were analyzed and showed more platelets than in the mixture. This indicates that spheronized particles are preferably bound in the agglomerates. These findings show that, based on the discussed sample preparation and a 3D image analysis in connection with X-RMT, particle shapes of micronized particles can be discriminated.

Graphical abstract

Keywords

Multidimensional separation; X-ray microtomography; Selective agglomeration; Particle shape; Graphite

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