Transformation of zeolite A into hydroxysodalite: II. Growth kinetics of hydroxysodalite microcrystals

• Published in: Journal of crystal growth Vol. 75; no. 3; pp. 561 - 572
• Main Authors: SUBOTIC, B, SEKOVANIC, L
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 1986; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of crystal growth; physics of crystal growth; Physics; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Crystal growth; Basic solution; Heterogeneous nucleation; Aluminium Sodium Chlorides Hydroxides Silicates Mixed; Supersaturation; Kinetics; Experimental study; Dissolution; Microcrystal; Growth from solution
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/0022-0248(86)90102-8

The influence of supersaturation on the transformation kinetics and on the growth rate of hydroxysodalite particles (microcrystals) has been studied during the transformation of zeolite A into hydroxysodalite in sodium hydroxide solutions of various concentrations at 353 K. Analyses of the transformation kinetics have shown that the transformation is a solution-mediated process in which the growth of hydroxysodalite particles, formed by heteregeneous nucleation, is due to simultaneous diffusion and surface reactions of monomeric silicate and aluminate anions present in the supersaturated solutions. Based on such a model, the growth rate kinetics can be mathematically described as: dDdtT = kg∫tO[ΔCHS(L)]2[D(tT)]m, where D(tT) is the size of the hydroxysodalite particles at transformation time tT, kg is the growth rate constant, ΔCHS(L) is the difference between the concentration CHS(L) of hydroxysodalite dissolved in the liquid phase and the concentration CHS(s), corresponding to the solubility of hydroxysodalite under given experimental condition, and m ≈ 0.326. The equations of the transformation kinetics, derived on the basis of the described growth model, are in good correlation with the experimental data.