TY - JOUR
T1 - Effects of gravity on zeolite crystallization from solution
AU - Song, Hongwei
AU - Ilegbusi, Olusegun J.
AU - Sacco, Albert
N1 - Funding Information:
This work was supported by the NASA Center for Advanced Microgravity Materials Processing (CAMMP) at Northeastern University.
PY - 2005/4/15
Y1 - 2005/4/15
N2 - A mathematical model is developed to describe the effect of gravity on crystallization kinetics and particulate properties in a well-mixed zeolite crystal growth process. Particle sedimentation and convection due to gravity result in a sedimentation layer, where the settled crystals compete for a limited amount of nutrient. This model is based on heterogeneous and secondary nucleation mechanisms. It also assumes a size-dependent power-law growth mechanism that indicates a surface reaction-controlled growth rate at high supersaturation and a diffusion-controlled growth rate at low supersaturation. The growth rate significantly depends on the number of species that participate and govern the surface integration kinetics. The predicted transient nulceation and crystallization profiles, as well as the final particle size distribution are compared with zeolite particle size distribution (PSD) data obtained from synthesis done in low earth orbit. This simulation implies that secondary nucleation dominates the crystal formation on ground but is ruled out in low earth orbit compared to heterogeneous nucleation.
AB - A mathematical model is developed to describe the effect of gravity on crystallization kinetics and particulate properties in a well-mixed zeolite crystal growth process. Particle sedimentation and convection due to gravity result in a sedimentation layer, where the settled crystals compete for a limited amount of nutrient. This model is based on heterogeneous and secondary nucleation mechanisms. It also assumes a size-dependent power-law growth mechanism that indicates a surface reaction-controlled growth rate at high supersaturation and a diffusion-controlled growth rate at low supersaturation. The growth rate significantly depends on the number of species that participate and govern the surface integration kinetics. The predicted transient nulceation and crystallization profiles, as well as the final particle size distribution are compared with zeolite particle size distribution (PSD) data obtained from synthesis done in low earth orbit. This simulation implies that secondary nucleation dominates the crystal formation on ground but is ruled out in low earth orbit compared to heterogeneous nucleation.
KW - A1. Microgravity
KW - A1. Nucleation
KW - A1. Particle size distribution
KW - A1. Population balance
KW - B1. Zeolites
UR - http://www.scopus.com/inward/record.url?scp=15844396020&partnerID=8YFLogxK
U2 - 10.1016/j.jcrysgro.2004.12.161
DO - 10.1016/j.jcrysgro.2004.12.161
M3 - Article
AN - SCOPUS:15844396020
VL - 277
SP - 623
EP - 630
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
SN - 0022-0248
IS - 1-4
ER -