An Efficient Method for Carbon Dioxide Sequestration Using Semidry Flue Gas Desulfurization Ash

As a sort of industrial solid waste, semidry flue gas desulfurization ash (SFGDA) exhibits notable attributes such as elevated calcium and alkali content, which facilitate the mineralization of CO2 flue gas. Herein, a novel approach is employed to effectively fix CO2 using SFGDA via a combination of direct and indirect mineralization processes. During the direct mineralization stage, CO2 reacts with calcium ions in the SFGDA slurry, resulting in the reduction of calcium ions' concentration and the dissolution of sparingly soluble calcium salt. Subsequently, in the indirect mineralization stage, a moderate quantity of ammonia solution is introduced into the slurry. More calcium ions are generated to fix a large quantity of low-concentration CO2. Results demonstrate that at 40 degree celsius, 300 rpm, 10% CO2, and 0.78 mol/L ammonia solution, the mineralization efficiency maintains an amazing 216 kg of CO2 per ton of SFGDA. This approach provides an alternative candidate for industrialized treatment of SFGDA and CO2 flue gas.