Kinetics and thermodynamics of sucrose crystallization from pure solution at different initial supersaturations

Growth rates of sucrose crystallization from pure solutions of initial relative supersaturation levels between 0.094 and 0.181 were studied in agitated crystallizer at 313.13 K. Birth and spread model was applicable for the obtained growth rate data in this range of supersaturation and used to estimate the principal growth parameters. The estimated interfacial free energy varied inversely with supersaturation from 0.00842 to 0.00461 J/m2, respectively. The obtained kinetic coefficient changed with the initial supersaturation from 9.45 × 10− 5 to 2.79 × 10− 7 m/s. The corresponding radius of the 2D (two dimensional) critical nucleus varied from 7.47 × 10− 9to 1.46 × 10− 9 m. Predominance of surface integration or volume diffusion mechanism during the growth process was assessed using the calculated activation free energies of the 2D nucleation process. An acceptable confirmation of the calculated radius of the critical 2D nucleus was found using atomic force microscopy (AFM) technique. The calculated interfacial free energy between the saturated sucrose solution and the crystal surface was found to be 0.02325 J/m2.