Preparation of CaCO3 using mega-crystalline calcite in electrical furnace and batch type microwave kiln

Mega-crystalline calcite (m-CC) breaks apart easily during calcination, and cannot be easily converted to CaO due to its characteristic that requires massive heat consumption. To solve this problem, the calcination characteristics were compared using electrical furnace (EF) and batch type microwave kiln (BM). After hydrating the manufactured CaO, Ca(OH)2 was produced, and through the carbonation process, CaCO3 was synthesized.The results of the XRD pattern of CaO that was formed through calcinations indicated that decarbonation reaction occurred as 98.2 wt.% by EF for 240 min, and 97.8 wt.% by BM for 30 min at the same temperature of 950 °C. Hydration results revealed that CaO by EF was high-reactive whereas CaO by BM was medium-reactive. CaCO3 was synthesized through the carbonation process. At 25 °C, in both cases, colloidal-shaped CaCO3 was found, and the more spindle-shaped CaCO3 by cubic-shaped self assembly was synthesized at higher temperatures. However, in case of EF, Ca(OH)2 existed in products.