화학공학소재연구정보센터
KAGAKU KOGAKU RONBUNSHU, Vol.24, No.6, 940-944, 1998
Precipitation of calcite from calcium carbonate intermediate in agitated glass beads slurry
Precipitation of calcite is studied by agitated mixed bed of calcium carbonate intermediate and glass beads in a batch crystallizer. In test results obtained by addition of glass beads of 1.0x10(5) particles, a calcium carbonate intermediate was transformed to the mixture of calcite and vaterite by addition of small glass beads of 105 and 155 mu m average diumeter, but calcite precipitated dominantly by addition of large glass beads of 390, 575 and 791 mu m average diumeter. Precipitated number of calcite increases with the cube of the average size of glass beads. The energy generated by collision of glass beads is considered to promote the transformation from intermediate to calcite. Precipitated number of calcite increases with square of the cube root of the number of added glass beads, and was affected by agitation speed of an impeller. Equilibrium concentration of calcium carbonate intermediate was 3x10(-3) mol/l and growth rate of calcite was 0.9 mu m/min when enough amount of calcium carbonate intermediate coexists.