Material movement in the rotary kiln is a very complicated situation, movement speed, and the uniform degree of calcining directly affects the quality of the product. Along with the material in the rotary kiln constantly rolling and moving, lime particles start to contact with flame radiation and transfers heat. Under the influence of flame radiation temperature, the chemical reaction of material properties happens. This is called that material was calcined to be lime from the limestone.

For the calcination of active lime, it has characteristic of fast-burning and quenching. In order to ensure that the activity of lime, when burnt-lime left the flame radiative zone, heat transfer condition of lime is beginning to change, from accept air convection heat transfer, kiln lining, conduction heat transfer and flame radiation heat transfer between particles into outward diffusion heat release. Crystal structure is about to change.

In order to prevent the lime clinker discharged from active lime rotary kiln changing into crystal structure in the high temperature. For cooling the lime out of kiln, it should be finished in a short time. Vertical cooler is an ideal cooling container. High-heat lime stays in cooler about 30 minutes, in the intense heat exchange can be cooled to below 100 ℃, thereby effectively preventing the crystal to grow up. The process of heat exchange is mainly on heat dissipation. Mechanical wind blows out and takes away the material contained in heat; heat through convection heat transfer heats the air.