Calcium carbonate granulation in a fluidized-bed reactor: Kinetic, parametric and granule characterization analyses

The granulation of calcium carbonate (CaCO3) exhibited high industrial demand due to its wider application and importance in cement, paper, glass and steel manufacturing. This paper investigated the granulation kinetics of CaCO3 through the fluidized-bed homogeneous granulation (FBHG) process during the homogenous nucleation stage. The CaOH solution was used as source of Ca2+ reactant, while K2CO3 solution as source of CO32- precipitant. The mechanism followed the pseudo-second order kinetics. The calcium cation attracts the carbonate anion to form CaCO3 through a double displacement chemical reaction. The calcium-is-to-carbonate molar ratio ([Ca2+]/[CO32-]) was varied into 1.25 to 2.50, with constant values of pH = 10 +/- 0.2, influent carbonate concentration = 10 mM and total influx flow rate = 60 mL min(-1). The ideal [Ca2+]/[CO32-] condition was found to be at 1.50 that means the precipitation of CaCO3 grew and stayed inside the reactor. At the same condition, granules of diameter size of 1 mm to 2 mm were collected with a subrounded shape and smooth surface as shown by its surface morphology. The characterization analysis also verified the high purity of CaCO3 aragonite granules precipitated through the FBHG process.