Optimization of calcium carbide residue utilization for producing high-quality calcium carbonate

Abstract

In light of the current situation where the utilization of calcium carbide slag yields low profits but holds significant potential for reducing carbon emissions, ammonium acetate was employed to leach calcium carbide slag. It also played a crucial role in regulating the products of indirect carbon dioxide carbonation when mixed with glycine and lye. Ammonium acetate's significance underscores its dual role in both the leaching and carbonation processes. This process yielded calcium carbonate with particle sizes smaller than 100 nm, with a purity of 98% and a single vaterite phase. The calcium carbide residue demonstrated an impressive CO₂ uptake rate of 23.5%. Ammonium acetate exhibited an efficiency of 79.2% as a leaching agent. The ammonium acetate method demonstrated enhanced environmental friendliness and facilitated a more efficient carbon uptake rate of 23.5% compared to conventional indirect methods. Furthermore, the addition of lye, glycine, and ammonium acetate effectively extended the nucleation time of the calcium carbonate crystals and induced the formation of more vaterite intermediates with smaller particle sizes. The influence mechanism of compound additives on the carbonation reaction was revealed through kinetic analysis and molecular dynamics. This innovative approach offers a promising avenue for simultaneously treating solid waste and reducing CO₂ emission. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.