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.

Research on Utilizable Calcium from Calcium Carbide Slag with Different Extractors and Its Effect on CO2 Mineralization

“…Microscopic images show that impurities are attached to the surface. XRD analysis of calcium carbonate synthesized by direct carbonation and ammonium salt are aligning with prior experimental findings [ 32 , 49 ].…”

“…Microscopic images show that impurities are attached to the surface. XRD analysis of calcium carbonate synthesized by direct carbonation and ammonium salt are aligning with prior experimental findings [32,49]. To compare the difference between the extraction process of utilizable calcium ammonium salt and the extraction process of acid in the CO 2 mineralization reaction, the solution after extraction of utilizable calcium by hydrochloric acid was added to ammonia, the pH was adjusted to 10, and CO 2 was injected.…”

“…At an NH 4 /Ca ratio of 2:1 and an L/S ratio of 20:1, calcium extraction efficiency reached more than 90%. This rate surpasses the efficiency of other recent studies on the extraction of ammonium salt [ 49 ].…”

“…At an NH 4 /Ca ratio of 2:1 and an L/S ratio of 20:1, calcium extraction efficiency reached more than 90%. This rate surpasses the efficiency of other recent studies on the extraction of ammonium salt [49]. After determining the reaction conditions of L/S and NH4/Ca, the reaction temperature and time were experimentally explored.…”

“…Furthermore, the buffering effect of acetate at the end of the mineralization reaction can delay the further reaction of CaCO 3 . In contrast to similar recent studies on CO 2 mineralization using ammonium salt, which focus on a single CaCO 3 synthesis pathway and ignore the influence of impurities on the crystal form of CaCO 3 [ 37 , 49 ], this work studied the process conditions of ammonium acetate extraction of calcium carbide slag, and the effect of the acid extraction and ammonium salt extraction processes on the selective dissolution of Ca 2+ was compared. High selective dissolution of utilizable calcium from industrial solid waste was achieved.…”