Sulfur Dioxide → Magnesium sulfite

Participants

Reaction Steps

In lieu of a limestone or lime-based scrubbing system, flue gas containing sulfur dioxide may be treated by passing it through a scrubbing unit that utilizes a magnesium-containing scrubbing agent, e.g., a magnesium hydroxide slurry. The magnesium hydroxide reacts with sulfur dioxide to produce magnesium sulfite and magnesium bisulfite. The magnesium hydroxide slurry also reacts with hydrochloric acid in the flue gas, producing magnesium chloride, although there is very little hydrochloric acid in the flue gas compared to sulfur dioxide. The following chemical reactions occur in the scrubbing unit: SO2+Mg(OH)2→MgSO3+H2O  (1) H2O+SO2+MgSO3→Mg(HSO3)2  (2) Mg(HSO3)2+Mg(OH)2→2MgSO3  (3) 2HCl+Mg(OH)2→MgCl2→2H2O  (4)

Provenance & Evidence