<p>CO₂ capture, utilization and sequestration technology is currently a global research hotspot with increasing CO₂ emission and rising atmospheric temperatures. Flue gas desulfurization gypsum (FGDG) was used to realize CO₂ mineralization in waste NaOH lye in a pilot scale bubble tower. The effects of the ionic strength, CO₂ flow rate, reaction temperature, and liquid level in the reactor on the properties of the mineralization products and the CO₂ mineralization efficiency were investigated using thermogravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis. The experimental results indicated that ionic strength, reaction temperature and CO₂ flow rate significantly influenced the CO₂ mineralization efficiency of FGDG. The CO₂ mineralization efficiency reached 92.15% under the optimized conditions (the ionic strength: 10⁻² mol·L⁻¹, CO₂ flow rate: 20&#xa0;L·h⁻¹, reaction temperature: 60&#xa0;°C, liquid level: 50&#xa0;cm). The liquid level has a strong effect on the particle size distribution of mineralized products. A higher liquid level promotes the formation of mineralized products with smaller particle sizes. These products consist of a single cluster of crystals and the main component is calcium carbonate. The pilot scale results demonstrate optimized evidence for CO₂ mineralization using FGDG in waste lye. Therefore, this approach enables the comprehensive utilization of three types of waste-gas, liquid, solid- generated produced in coal-fired power plants.</p>