Determination of Crystal Growth Rate and Morphology of Barium Carbonate Crystals in a Semi-batch Crystallizer

Document Type: Research Article

Authors

1 Faculty of Chemical Engineering, Amirkabir University, Tehran,, I.R. IRAN

2 Faculty of Chemical Engineering, Iran University of Science and Technology, Tehran, I.R. IRAN

3 Department of Chemistry, Malek Ashtar University of Technology, Tehran, I.R. IRAN

Abstract

A semi-batch crystallization system is used to determine growth kinetics and morphology of barium carbonate crystals, under a constant pH value and constant temperature in the various relative supersaturations. Results show that crystal growth rate satisfies a first-order kinetic expression at high relative supersaturation, while at relative supersaturation values lower than 3,  the kinetic expression is second order. The crystal growth of barium carbonate follows the Burton, Cabera, and Frank mechanism by the kinetic expression G=as2 tanh (b /s). The kinetic parameters obtained from low to high supersaturation ratio by using a numerical methods are a=9.5×10-7 ms-1 and β=1.35×10-2. The investigations show that the pH values and relative supersaturation of solutions have an important role on the crystal morphology of barium carbonate and the forms of observed crystals are floc, candy-like, pillar-like, olivary and olivary with end dendrite with respect to operating condition.

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