Preparation of calcium carbonate with microstructure and nanostructure from carbide slag for CO2 sequestration by using recyclable ammonium chloride

Based on the composition characteristics of carbide slag and the application of polyvinyl chloride, a method of preparing calcium carbonate with microstructure and nanostructure by using carbide slag as a raw material and ammonium chloride as a leaching agent was proposed. The factors for the preparation of calcium carbonate and the effects of different conditions on the crystal phase, grain size, and morphology of calcium carbonate were systematically studied. The results showed that the nanosized calcium carbonate was prepared at 60 mL/min, 25 °C, no additional ammonia, and 60 min. The product of spherical vaterite was in accordance with the relevant standards for the industrial precipitation of calcium carbonate. Moreover, the reuse of carbonation filtrate was realized. The crystal phase, grain size, and morphology of the carbonation product could be controlled by adjusting the reaction conditions. The manuscript provided a new idea for resource utilization of carbide slag and preparing nanocalcium carbonate.