Abstract: Titanium dioxide was mostly fed into the calcination rotary kiln in wet way. As the drying section of free water accounted for 1/3 of the total length of the rotary kiln，the production efficiency and the heat utilization rate were very low.In the new technology，cake-like material was put into the flash dryer at first，and then desiccated by the waste hot gas from the tail of rotary kiln.After crashed，the material was sent to rotary kiln for calcination.The new technology could make the temperature of the emission reach 100 ℃ or so from 300~350 ℃.Thus the heat utilization was improved，the cost of tail gas cooling was reduced and the production capacity of rotary kiln could be also increased by 30%.

Key words: rotary kiln, waste heat, titanium dioxide, flash drying