Air Pollution Control and Prevention

: Formula that represents the process of “scrubbing” products of industrial combustion processes. Sulfur dioxide gas is removes by using an aqueous solution of calcium hydroxide, also called limewater. The sulfur dioxide reacts with the limewater to form solid calcium sulfite. Scrubbers that utilize this “wet” scrubbing method can remove up to 95% of sulfur oxides.

Another process for scrubbing that utilizes magnesium hydroxide instead of limewater. The sulfur dioxide dissolves in the water and reacts with the magnesium hydroxide to form a salt. The magnesium sulfite that is formed can be isolated and heated to regenerate sulfur dioxide. The recovered sulfur dioxide can be collected and used as a raw material in other commercial processes.