Resistance in preheater system is discussed and index for evaluating preheater resistance is raised． Measures and requirements for resistance reduction in preheater system are set forth by the author．

The paper presents the effect of sodium silicate amount on the property of alkali slag cement (ASC) under the condition of thermal excitation. The results shows that two important effects of "thermal excitation" were developed by means of steam curing: (1) when sodium silicate adding amount in the range of 8.89％?18.45％, the time limit of excitation would be shorten to 1／10 of normal curing; (2) when sodium silicate content keeps at ＞12％～13％, the strength of ASC keeps unchanged and 12h compression strength is over 50Mpa. XRD and SEM analysis shows that the hydration products in alkali slag paste is as same as under normal temperature when having steam curing, which is mainly composing C－S－H, but the crystallinity is low.

In view of difficult temperature measurement of burning zone in rotary kiln, a dynamic image temperature measurement system is established based on color comparason temperature measurement in combination with computer visual and image gethering technology． In connection with the low precision of traditional color comparason temperature measurement, a correction is made on two－color ratio according to actual working condition of cement kiln, thus the measuring precision is improved by a big margin．