Periodicity in Calcination Temperature of a Rotary Kiln

This paper studies the periodic structure in the time series of the calcination temperature of a Lithopone rotary kiln. Fourier method, which was well known in spectral analysis, indicated prominent period of 142.22 seconds. For this method did not give the reliability of the periodicities found, a curse fitting method was carried out for validation. After that, the reason of the periodicity was clarified based on the measuring mechanism and the inner structure of the kiln. Furthermore, inference that the period was inverse proportional to the rotary speed come out and it was proved by studying another series under a different rotary speed.