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Morphology of alumina granules obtained by spray freeze drying with twin‐fluid atomization
Author(s) -
Kuzmin Ruslan,
Veselov Sergey,
Cherkasova Nina,
Bataev Vladimir
Publication year - 2021
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/ijac.13802
Subject(s) - granule (geology) , materials science , polyvinyl alcohol , spray drying , chemical engineering , composite material , suspension (topology) , morphology (biology) , mathematics , homotopy , pure mathematics , biology , engineering , genetics
This study presents the results of the morphological dependence of alumina granules obtained by spray freeze drying (SFD) with twin‐fluid atomization. It is shown that the introduction of 1‐, 2‐ and 4‐wt.% polyvinyl alcohol (PVA) as a binder in an alumina suspension leads to the formation of irregular granules. Depending on atomization conditions, spherical, “tadpole‐like,” granule‐satellite and granule aggregates may form during SFD. Increasing the flight time of droplets before the fixing of their shape when they come in contact with liquid nitrogen effectively contributes to the spheroidization of alumina granules. Compacting PVA‐free SFD granules leads to the formation of diagonal flaws in a green‐body structure. Adding PVA prevents the abovementioned defects by increasing the strength of alumina granules. Increasing the amount of PVA leads to an increase in “tadpole‐like” granule content and, consequently, a decrease in a green‐body density.