Sequestration of carbon dioxide by the waste gypsum

PURPOSE: A method for fixing carbon dioxide with waste gypsum is provided to make pure calcite with good crystallinity by reacting an ammonia solution, byproduct gypsum, and the carbon dioxide under low temperature, and to offer environmental friendliness. CONSTITUTION: A method for fixing carbon dioxide with waste gypsum includes a step for manufacturing slurry by reacting a compound and the carbon dioxide while mixing an ammonia solution containing 1 ~ 28 weight% of ammonia and byproduct gypsum(110) and a step for obtaining single-phase calcite and sulfur by drying solids and liquid separated from the slurry(120). The reaction temperature of the first step is 30 ~ 70°C. The single phase calcite is formed by drying the solids under 50 ~ 90°C. The sulfur is formed by drying or freezing-drying the liquid under 40 ~ 100°C.