Vaterite CaCO_3 crystals with a spherical shape were successfully prepared with aspartic acid(Asp) as the interferon inducer.The effects of CO_2 flow rate,reaction temperature,and Asp concentration on polymorph and morphology of calcium carbonate were investigated,and crystalline products were characterized by X-ray diffraction,field emission scanning electron microscopy,and laser particle analyzer.The experimental resulted indicated that CO_2 flow rate had no effect on the polymorph of CaCO_3,but on the mo...