Effect of various factors on the particle size of calcium carbonate formed in a precipitation process

The effect of various factors on the particle size of precipitated calcium carbonate formed in a wet carbonation process has been investigated experimentally. The calcium carbonate particles were fabricated in a glass reactor by bubbling CO2 through a calcium hydroxide solution of 2.5% by weight. The particle size distribution of the particles was determined using a laser technique. The operating factors investigated include the CO2 bubble size (with frit pore size of 17-40 or 101-160 mu m), the CO2 gas flow rate (3.5 and 4 L/min), the CO2 concentration (25 and 100%), the reaction temperature (25 and 80 degrees C) and the additives (terpineol 0.1 and 1 vol%, EDTA 0.25 and 1 wt%). It was found that the average particle size was between 1 and 3 mu m. The particle size was reduced slightly with the decrease of the CO2 bubble size, and decrease of the CO2 concentration. The particle size distribution was affected significantly by the addition of terpineol and EDTA, but not necessarily reduced as reported previously