Resource utilization of flue gas calcium-based desulfurization ash: a comprehensive review

Calcium-based desulfurization ash (CDA) is mainly produced in dry and semi-dry flue gas desulfurization processes. The property of CDA is extremely unstable because its main component, calcium sulfite, makes it difficult to be directly applied to the field of building materials. The modification of desulfurization ash can be realized by high-temperature oxidation and wet oxidation. After modification, CDA can be widely used in building materials. Hydrothermal oxidation has broad development prospects because it can complete the oxidation of CDA and the removal of impurity elements at the same time. CDA can be used to prepare high value-added products of calcium sulfate whiskers and ecological rubber fillers.