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Effects of Al 2 (SO 4 ) 3 and K 2 SiO 3 Impurities on the Crystallization of K 2 SO 4 from Aqueous Solution
Author(s) -
Luo Mengjie,
Liu Chenglin,
Song Xingfu,
Yu Jianguo
Publication year - 2021
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.202000052
Subject(s) - impurity , crystallization , nucleation , metastability , analytical chemistry (journal) , aqueous solution , materials science , chemistry , chromatography , organic chemistry
The results of an investigation of the effect of Al 2 (SO 4 ) 3 and K 2 SiO 3 impurities on the crystallization of K 2 SO 4 from aqueous solutions are described and discussed. The metastable zone width (MSZW) of K 2 SO 4 aqueous solutions, without and with known concentrations of the impurities, saturated at 40 and 60 °C is determined, using ultrasonic sensor by the controlled solution cooling method at predefined cooling rates R . It is observed that the value of the MSZW of the two types of saturated solutions increases with an increase in the cooling rate R and the concentration C i of the two impurities. The experimental data of the dependence of MSZW on cooling rate and impurity concentration are analyzed by an approach based on the classical 3D nucleation theory. The results showed that: 1) both impurities suppress the formation of 3D nuclei by physically blocking the active sites on their surfaces, 2) Al 2 (SO 4 ) 3 impurity is more effective than K 2 SiO 3 impurity, and 3) the purity of the K 2 SO 4 crystals is insignificantly affected by these impurities, but the morphology and size of the obtained crystals are influenced strongly by Al 2 (SO 4 ) 3 impurity.