As a soluble sodium salt of sulfurous acid, Sodium sulfite (Na2SO3) shows blenching, de-sulfurizing and dechlorinating properties which is widely applied in various fields. It is primarily used in the pulp and papermaking industry due to its blenching activity. It can serve as a good additive to help preserve the fresh appearance of good products. Besides, sodium sulfite is a component in many pharmaceuticals, which is effective to maintain the potency and stability of drugs. It can also be applied for water treatment as an oxygen scavenger agent and applied in flue gas desulfurization and preservation of photo developer solutions, etc.