What Is Calcium Sulfite?
Calcium sulfite is a compound formed from calcium, often encountered as calcium sulfite 0.5 hydrate. It typically appears as a white crystalline substance or powder. This compound is insoluble in water but dissolves in sulfurous acid and dilute hydrochloric acid, releasing sulfur dioxide. It can also decompose, emitting sulfurous acid gas, and therefore requires careful handling.
Calcium sulfite can be produced by reacting calcium oxide, calcium carbonate, or calcium hydroxide with sulfur dioxide. When exposed to air, it gradually oxidizes to calcium sulfate.
Uses of Calcium Sulfite
As a reducing agent, calcium sulfite is primarily used to remove residual chlorine from tap water. Chlorine, added to tap water for disinfection, imparts a characteristic odor. Calcium sulfite effectively removes free residual chlorine, working instantaneously. It is particularly advantageous in water purifiers with high water flow rates due to its minimal reducing agent requirement and rapid reaction time compared to conventional methods like activated charcoal. Furthermore, its efficacy in removing chlorine from hot water makes it a popular choice for water-purifying shower heads.