From the newly built cement projects worldwide and the production practice of dozens of new rotary kiln that have been launched into operation at home and abroad, the new rotary kiln has shown the incomparable advantages over other kind of kilns in technology, operation of he machine as well as the infrastructure performancethe.
The study shows that, in the decomposition process of CaCO3, there will be many nascent state oxide, which mainly are the CaO and SiO2. These nascent state oxides have high activation energy and a strong reaction. In the kiln of the predecomposition, the decomposition rate of the materials into the kiln is at least more than 90% and only a small amount of the carbonate still remains to be decomposed in the rotary kiln. The high temperature zone of the kiln is only limited in the radiation section of the flame, as for the kiln of the predecomposition whose general aspect ratio L / D = 14~17, the materials that have completed the decomposition task will stay within the transition zone of 900 ~ 1 300 ? for some time, generally for 15 to 16 min, delaying the process of heating of materials. Therefore, the activation energy and the reaction of the nascent state oxide can not be used timely and adequately. Because in this section, there is no enough heat to realize the rapid warming, which restricts the grain and sintering of the clinker, making the structure of the clinker poor and affecting the quality and grindability of the clinker.
But in the new rotary kiln, the material just stay in the transition zone for 5 ~ 6 min and then the material will immediately enter the firing zone. The activation energy and reactivity of the nascent state oxide can be used fully and timely, which can reduce the firing temperature and reducing the heat loss of the exhaust gas so that the heat consumption will be decreased. In this case, the grain of the clinker minerals is good and they appear the microcrystalline and microporous structure, which not only can improve the clinker strength and grindability, but also can reduce the power consumption of cement grinding. In addition, the length of the kiln is shortened, which reduces the heat loss and decreases the transmission power.