At present, the world's use of ultrafine vertical mill amount to more than 200 kinds. After decades of continuous exploration and practice in the thermal power plant on the application of the processing, only 10 kinds are preserved.

The most important kind is the ultrafine vertical mill. Ultrafine vertical mill is currently the most widely used desulfurization technology, and its principle is to crush blocks of limestone into powder by using ultrafine vertical mill, and then limestone powder is made into slurry as the desulfurization absorber to mix with gas which enters the absorption tower.

Sulfur dioxide in the flue gas and calcium carbonate in the slurry and the incoming air reacts to form gypsum. The sulfur dioxide in flue gas is expelled out, avoiding environmental pollution caused by the large number of emission.