Synthesis of vaterite CaCO3 micro-spheres by carbide slag and a novel CO2-storage material

•Vaterite CaCO3 was prepared without any outside additives besides the reactions.•CO2 Storage Material (CO2SM) and carbide slag were used to prepare CaCO3.•Ethylenediamine and/or ethylene glycol from the CO2SM was used as surfactants.•After precipitation, the filtered solution could circularly prepare CaCO3.

A facile and direct hydrothermal method for the crystallization of vaterite CaCO3 micro-spheres in the presence of carbide slag saturated limpid solution and a new CO2-storage material (CO2SM), which was obtained from an equimolar system of 1,2-ethylenediamine (EDA) + 1,2-ethylene glycol (EG) uptaking CO2 (ChemPhysChem., 16 (2015) 2106), was presented without any outside additives. It's worth noting that the morphologies of CaCO3 precipitates could be controlled as homogeneous spherical-like (pure vaterite) at the 100 g L−1 CO2SM concentration for 90 min at 100 °C, in which released EDA and/or EG from the CO2SM was used as surfactants. After the precipitation of CaCO3 crystals in 100 g L−1 CO2SM solution, the filtered solution could not only be reused to absorb CO2, but also to prepare the same crystal phase CaCO3 micro-particles repeatedly with the addition of carbide slag. Thus, this novel synthesis process of CaCO3 micro-particles with carbide slag and the CO2SM offers an alternative way for the comprehensive utilization of CO2 and the solid waste carbide slag.