Titanium dioxide rotary kiln

working process of Titanium dioxide rotary kiln

1. The filtered titanium dioxide hydrolysate filter cake is fed into the tail end of the titanium dioxide rotary kiln, which has a certain slope and rotates slowly. At the same time, clean flames and hot air are blown into the kiln from the combustion mixing chamber at the kiln head to dehydrate and calcine the filter cake.
2. The dehydrated and calcined titanium dioxide hydrolysate filter cake, processed at temperatures above 1000°C, rolls along the circumferential direction and moves along the axial direction (from the high end to the low end) within the inclined titanium dioxide rotary kiln. During this process, a series of physical and chemical changes occur, including dehydration, desulfurization, crystal phase transformation, and particle growth, leading to the formation of titanium dioxide products with a certain crystal structure.
3. The titanium dioxide is discharged through the double hydraulic flip discharge valve at the lower part of the kiln head cover and falls into the cooling drum for cooling. It is then conveyed to the powder storage hopper by a bucket elevator for crushing.
4. A large amount of exhaust gas generated during combustion is discharged from the kiln tail. This exhaust gas contains combustion products, water vapor, sulfur trioxide, and some titanium dioxide dust (commonly known as kiln ash). To improve the recovery rate, the exhaust gas is sent to a dust collection system to recover the titanium dioxide dust. Common methods used in industry include gravity dust collection (such as settling chambers), wet dust collection (spray devices), centrifugal dust collection (cyclone separators), and electrostatic dust collection (electrostatic precipitators). After separating the dust, the exhaust gas still contains a certain amount of sulfur trioxide. It is then treated in a sulfur trioxide absorption device to reduce emissions to meet the discharge standards before being released.
5. Controlling the calcination conditions is an important step in determining the crystallization of titanium dioxide. Proper calcination temperature ensures complete desulfurization and dehydration of titanium dioxide, minimizes lattice defects in titanium dioxide crystals, and avoids affecting its whiteness. Therefore, controlling the critical temperature points, matching the feed rate with the kiln rotation speed, increasing the combustion chamber, preventing material and flames from touching, and preventing sintering are crucial in the control of the calcination process.