The Limestone-gypsum method is used to treat SO2 in limestone or lime slurry and flue gas. The desulfurization product gypsum can be disposed of or can be re-used for comprehensive utilization. It is the most widely used desulfurization technology in the world. The reliability of the desulfurization system reaches more than 99% and the desulfurization efficiency reaches 98%.

The characteristics of limestone method: the source of absorbent is wide, the desulfurization efficiency is high, the product use is little, the occupation area is wide, and the operation cost is high.