Analysis of Nonideal Shape Evolution during Potash Alum Crystallization Using Microcomputed Tomography and Three-Dimensional Image Analysis

Schiele, Simon; Antoni, Felix; Meinhardt, Rolf; Briesen, Heiko

doi:10.1021/acs.cgd.0c01644

Cited by 11 publications

(25 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure D–F illustrates the growth of three seed crystals of our previous study . The crystal sizes were increased by factors of 1.78, 2.29, and 1.60, respectively, and the volumes were increased by factors 3.7, 3.9, and 3.5.…”

Section: Resultsmentioning

confidence: 86%

“…This mesh was smoothed by applying the function smoothpatch , three times (parameter itt = 3) to smoothen steps in the surface caused by discretization into voxels by μCT. Previously, we reported that this did not affect the volume or shape of similar crystals . For the overlaying procedure, the rotation and center point of the last μCT image served as reference.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…and distances of the crystal’s faces to its center of mass. The procedure only assumes symmetry for opposing faces because we have observed that PA crystals do not necessarily have an octahedral shape.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…To further evaluate the shape of the PA crystals, we applied a 3D aspect ratio Φ n before . The vector Φ n describes the symmetry of a potash alum crystal …”

Section: Materials and Methodsmentioning

confidence: 99%

“…The reference point is often chosen as the center of mass of a crystal. It is also convenient to use H-representations to model crystallization processes ,,− because growth occurs in the normal direction of the faces. Therefore, the growth of crystals can be described through an increase in the face distances that are used in H-representations.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Growth of Abraded Crystals Tracked in Three Dimensions

Schiele

Hupfer

Luxenburger

et al. 2021

Crystal Growth & Design

Self Cite

View full text Add to dashboard Cite

The interaction between crystal growth and abrasion is essential during crystallization. Although each of these phenomena has been independently studied in the literature in detail, their interaction is not well understood. Here, we present a method to track the growth of abraded potash alum crystals in three dimensions. The method is based on micro-computed tomography. This technique distinguishes between different growth domains in three dimensions and is used to track the growth of crystal faces and abraded regions. We observed how abraded regions grew faster than crystal faces. Therefore, growth leads to ideally facetted crystals. Further, growth rates in all directions were derived and used to parametrize a growth model. The model is able to describe the size and shape evolution of abraded potash alum crystals in three dimensions.

show abstract

Section: Resultsmentioning

confidence: 86%

Section: Materials and Methodsmentioning

confidence: 99%

Section: Materials and Methodsmentioning

confidence: 99%

“…To further evaluate the shape of the PA crystals, we applied a 3D aspect ratio Φ n before . The vector Φ n describes the symmetry of a potash alum crystal …”

Section: Materials and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Growth of Abraded Crystals Tracked in Three Dimensions

Schiele

Hupfer

Luxenburger

et al. 2021

Crystal Growth & Design

Self Cite

View full text Add to dashboard Cite

show abstract

Online 3D Characterization of Micrometer‐Sized Cuboidal Particles in Suspension

et al. 2022

View full text Add to dashboard Cite

materials (e.g., metal-organic frameworks) and catalysts, and the production of pharmaceutical, agrochemical, and food compounds. In all situations, particle sizing plays a key role in the design and control of particle properties and particle size and shape manipulation.Conventionally, a single characteristic length is used to describe particles, assuming a spherical geometry, or taking advantage of the concept of equivalent diameter. This assumption may be acceptable for irregular yet compact shapes, and is an established simplification functional to the description of various physical phenomena. [1] However, it is clearly incorrect when analyzing elongated or plate-like particles, i.e., with low sphericity, which are common crystalline products. [2] This leads to particle size and shape estimates that poorly match physical reality. [3][4][5] To describe both size and shape, at least two characteristic lengths are needed, which can be obtained through a number of 2D or 3D characterization techniques. [6][7][8][9] Such (offline and online) techniques, including micro-computed tomography (µCT), [10][11][12][13][14][15][16][17] holography, [18][19][20] structural light, [21] machine vision, [13,[22][23][24][25][26][27][28][29][30][31] confocal microscopy, [32] and surface imaging [33] have varying degrees of accuracy and complexity. Machine vision through image analysis (IA) has become an increasingly powerful tool, due to experimental simplicity, hardware improvements, and continual increases in available computational power. [8] For the online measurement of elongated, needle-like particles on the microscale, effective IA algorithms have been proposed and successfully used to track particle length and width distributions. This has enabled a better fundamental understanding of processes in particle technology. [34][35][36][37][38] By contrast, an experimentally validated methodology enabling the rapid and online measurement of cuboidal or plate-like particles has yet to be developed. Full 3D characterization is possible through µCT, but this comes with several downsides, such as extended scanning times and, in the case of powders, difficulties in particle segmentation. [14] 2D characterization by single projection imaging can be fast, but does not provide sufficient information to reliably extract characteristic lengths and shapes, whilst the accuracy of multiple projection imaging is compromised by particle orientation. [6,8] Other techniques, such as holography or surface imaging, are yet to be applied to, or are unsuited for online measurement purposes.Characterization of particle size and shape is central to the study of particulate matter in its broadest sense. Whilst 1D characterization defines the state of the art, the development of 2D and 3D characterization methods has attracted increasing attention, due to a common need to measure particle shape alongside size. Herein, ensembles of micrometer-sized cuboidal particles are studied, for which reliable sizing techniques are currently missing. Such particle...

show abstract