On the determination of crystallization kinetics from crystal size distribution data

1975 ◽  
Vol 30 (10) ◽  
pp. 1299-1301 ◽  
Author(s):  
S. Jančić ◽  
J. Garside
Keyword(s):  
Size Distribution ◽  
Crystallization Kinetics ◽  
Crystal Size ◽  
Crystal Size Distribution ◽  
Distribution Data

scholarly journals Analysis of CaF2 Precipitation Process in the Selected Static Mixers

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Piotr Maria Synowiec ◽  
Magdalena Stec
Keyword(s):  
Size Distribution ◽  
Crystal Size ◽  
Solid Phase ◽  
Fluid Dynamic ◽  
Crystal Size Distribution ◽  
Special Treatment ◽  
Precipitation Process ◽  
Continuous Precipitation ◽  
Static Mixers

In the paper, the analysis of the precipitation process of calcium fluoride in the selected static mixers was made. The Kenics and Koflo static mixers, as well as an empty pipe as a background, have been taken into consideration. The Kenics and Koflo types have been chosen as their inner shapes convenient for the realization of continuous precipitation processes as incrustation phenomenon and dangerousness of flow blocking are not as high as in other solutions. The main tasks were focused on the recognition of the precipitation kinetics (to get the knowledge of the relative supersaturation, nucleation sources, and mechanisms controlling the crystal growth), determination of conversion efficiency of the chemical reaction by which CaF2 is precipitated, the fluid dynamic conditions on crystal size distribution (CSD), and the identification of particles’ destruction sources as well. This paper is a primary work dedicated to the possibilities of a special treatment of the solid phase during its formation in order to obtain the required crystal size distribution (CSD) and to avoid the agglomeration when necessary. The results are very promising. As it will be shown, the special treatment of the precipitated solid substances in static mixers enables to create crystals with the required size and to eliminate the agglomeration phenomenon.

scholarly journals QEMSCAN as a Method of Semi-Automated Crystal Size Distribution Analysis: Insights from Apollo 15 Mare Basalts

2020 ◽  
Vol 61 (4) ◽  
Author(s):  
S K Bell ◽  
K H Joy ◽  
J F Pernet-Fisher ◽  
M E Hartley
Keyword(s):  
Data Collection ◽  
Size Distribution ◽  
Crystal Size ◽  
Crystal Size Distribution ◽  
Distribution Data ◽  
Nucleation Density ◽  
Distribution Analysis ◽  
Crystal Shape ◽  
Thin Sections ◽  
Crystal Residence

Abstract Crystal size distribution analysis is a non-destructive, quantitative method providing insights into the crystallization histories of magmas. Traditional crystal size distribution data collection requires the manual tracing of crystal boundaries within a sample from a digital image. Although this manual method requires minimal equipment to perform, the process is often time-intensive. In this study we investigate the feasibility of using the Quantitative Evaluation of Minerals by SCANing electron microscopy (QEMSCAN) software for semi-automated crystal size distribution analysis. Four Apollo 15 mare basalt thin sections were analysed using both manual and QEMSCAN crystal size distribution data collection methods. In most cases we observe an offset between the crystal size distribution plots produced by QEMSCAN methods compared with the manual data, leading to differences in calculated crystal residence times and nucleation densities. The source of the discrepancy is two-fold: (1) the touching particles processor in the QEMSCAN software is prone to segmenting overlapping elongate crystals into multiple smaller crystals; (2) this segmentation of elongate crystals causes estimates of true 3D crystal habit to vary between QEMSCAN and manual data. The reliability of the QESMCAN data appears to be a function of the crystal texture and average crystal shape, both of which influence the performance of the touching particles processor. Despite these limitations, QEMSCAN is able to produce broadly similar overall trends in crystal size distribution plots to the manual approach, in a considerably shorter time frame. If an accurate crystal size distribution is required to calculate crystal residence time or nucleation density, we recommend that QEMSCAN should only be used after careful consideration of the suitability of the sample texture and average crystal shape.

scholarly journals Modeling of Nucleation, Growth, Dissolution, and Disappearance of Paracetamol in Ethanol Solution for Unseeded Batch Cooling Crystallization with Temperature-Cycling Strategy

2020 ◽  
Author(s):  
Youngjo Kim ◽  
Yoshiaki Kawajiri ◽  
Ronald W. Rousseau ◽  
Martha A. Grover
Keyword(s):  
Size Distribution ◽  
Crystal Size ◽  
Process Analytical Technology ◽  
Ethanol Solution ◽  
Temperature Cycling ◽  
Crystal Size Distribution ◽  
Balance Model ◽  
Distribution Data ◽  
Concentration Data ◽  
Nucleation Growth

A population balance model (PBM) is developed for unseeded batch crystallization, with temperature-cycling strategies to control the crystal size distribution. The model is able to predict the evolution of crystal size distributions of crystallizing paracetamol from ethanol solutions considering the characteristics of primary nucleation, secondary nucleation, growth, dissolution, and disappearance of crystals. Process analytical technology (PAT) tools were employed to collect solute concentration data and crystal size distribution data. This model employs a boundary condition to describe the disappearance of crystals in temperature-cycling strategies where the temperature is increased and decreased repeatedly. As a result, the obtained model can describe the evolution of crystal size distribution when repetition of cooling and heating is carried out. Moreover, this model can be applied to investigate phenomena that are challenging to explain with experimental data alone, thereby we can gain insight and optimize the operation of the process.

scholarly journals Crystal size and shape distribution systematics of plagioclase and the determination of crystal residence times in the micromonzogabbros of Qisir Dagh, SE of Sabalan volcano (NW Iran)

2015 ◽  
Vol 66 (4) ◽  
pp. 257-268 ◽  
Author(s):  
Hamed Pourkhorsandi ◽  
Hassan Mirnejad ◽  
Davoud Raiesi ◽  
Jamshid Hassanzadeh
Keyword(s):  
Chemical Composition ◽  
Size Distribution ◽  
Crystal Size ◽  
Magma Mixing ◽  
Crystal Size Distribution ◽  
Distribution Data ◽  
Near Surface ◽  
Shape Distribution ◽  
Size And Shape ◽  
Sabalan Volcano

AbstractThe Qisir Dagh igneous complex occurs as a combination of volcanic and intrusive rocks to the south-east of the Sabalan volcano, north-western Iran. Micromonzogabbroic rocks in the region consist of plagioclase, alkaline feldspar and clinopyroxene as the major mineral phases and orthopyroxene, olivine, apatite and opaque minerals as the accessory minerals. Microgranular and microporphyritic textures are well developed in these rocks. Considering the importance of plagioclase in reconstructing magma cooling processes, the size and shape distribution and chemical composition of this mineral were investigated. Based on microscopic studies, it is shown that the 2-dimensional size average of plagioclase in the micromonzogabbros is 538 micrometers and its 3-dimensional shape varies between tabular to prolate. Crystal size distribution diagrams point to the presence of at least two populations of plagioclase, indicating the occurrence of magma mixing and/or fractional crystallization during magma cooling. The chemical composition of plagioclase shows a wide variation in abundances of Anorthite-Albite-Orthoclase (An=0.31–64.58, Ab=29.26–72.13, Or=0.9–66.97), suggesting a complex process during the crystal growth. This is also supported by the formation of antiperthite lamellae, which formed as the result of alkali feldspar exsolution in plagioclase. The calculated residence time of magma in Qisir Dagh, based on 3D crystal size distribution data, and using growth rate G=10−10mm/s, varies between 457 and 685 years, which indicates a shallow depth (near surface) magma crystallization and subvolcanic nature of the studied samples.

scholarly journals Modeling of Nucleation, Growth, Dissolution, and Disappearance of Paracetamol in Ethanol Solution for Unseeded Batch Cooling Crystallization with Temperature-Cycling Strategy

2020 ◽  
Author(s):  
Youngjo Kim ◽  
Yoshiaki Kawajiri ◽  
Ronald W. Rousseau ◽  
Martha A. Grover
Keyword(s):  
Size Distribution ◽  
Crystal Size ◽  
Process Analytical Technology ◽  
Ethanol Solution ◽  
Temperature Cycling ◽  
Crystal Size Distribution ◽  
Balance Model ◽  
Distribution Data ◽  
Concentration Data ◽  
Nucleation Growth

A population balance model (PBM) is developed for unseeded batch crystallization, with temperature-cycling strategies to control the crystal size distribution. The model is able to predict the evolution of crystal size distributions of crystallizing paracetamol from ethanol solutions considering the characteristics of primary nucleation, secondary nucleation, growth, dissolution, and disappearance of crystals. Process analytical technology (PAT) tools were employed to collect solute concentration data and crystal size distribution data. This model employs a boundary condition to describe the disappearance of crystals in temperature-cycling strategies where the temperature is increased and decreased repeatedly. As a result, the obtained model can describe the evolution of crystal size distribution when repetition of cooling and heating is carried out. Moreover, this model can be applied to investigate phenomena that are challenging to explain with experimental data alone, thereby we can gain insight and optimize the operation of the process.

XTL-SIZE: a computer program for crystal-size-distribution calculation from X-ray diffraction line broadening

1990 ◽  
Vol 23 (2) ◽  
pp. 136-137 ◽  
Author(s):  
R. D. Bonetto ◽  
H. R. Viturro ◽  
A. G. Alvarez
Keyword(s):  
Computer Program ◽  
Size Distribution ◽  
Crystal Size ◽  
Operation Mode ◽  
Crystal Size Distribution ◽  
Theory Approach ◽  
X Ray Diffraction ◽  
Acta Cryst ◽  
Distribution Calculation

A computer program has been written for the determination of crystal-size distribution in a direction perpendicular to an (hkl) crystal plane, from a digitized XRD peak. It implements an information theory approach devised by Guérin, Alvarez, Rebollo Neira, Plastino & Bonetto [Acta Cryst. (1986), A42, 30–35] and Alvarez, Bonetto, Guérin, Plastino & Rebollo Neira [Powder Diffr. (1987), 2, 220–224]. The program has a fully automated operation mode and owing to the very restricted amount of input data this program is specially suited to users with a limited knowledge of crystal-size-determination methods.

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