Preparation and Mechanism Study of Green Cyanamide Calcium

Calcium cyanamide was synthesized by the twice calcination of calcium oxide and urea which was different from the traditional calcium carbide method. Including reaction time, reaction temperature, and reaction molar ratio, the more suitable reactions were explored, which improved the utilization of urea and yield of calcium cyanamide. The phenomenon of visco-wall during the reaction process was alleviated by adding sodium chloride, and this effect was explained at the micro level. The chemical bond and weight change of the main byproducts and intermediate products in the reaction process were characterized systematically. A reaction model between urea and calcium oxide was constructed based on density functional theory (DFT), which complemented the reaction conditions and characterization results. Finally, the reaction mechanism between urea and calcium oxide was proposed.