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

Abstract

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 CO 2 flue gas. Herein, a novel approach is employed to effectively fix CO 2 using SFGDA via a combination of direct and indirect mineralization processes. During the direct mineralization stage, CO 2 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 CO 2 . Results demonstrate that at 40 °C, 300 rpm, 10% CO 2 , and 0.78 mol/L ammonia solution, the mineralization efficiency maintains an amazing 216 kg of CO 2 per ton of SFGDA. This approach provides an alternative candidate for industrialized treatment of SFGDA and CO 2 flue gas.