2009 Volume 49 Issue 5 Pages 609-617
The granulation process is known to be important to achieve high productivity in sinter process because the granulation of sinter mixture is connected with permeability of sinter bed. Past studies on the granulation in the drum mixer for sintering process mostly used the batch type drum mixer, hence their studies were on the raw material behavior for cross-section of the drum mixer. In contrast there were few reported on the raw material behavior for a drum axial and a residence time in a continuous type drum mixer. The raw material flows and the residence times have been investigated experimentally by using a continuous type drum mixer, and results were compared to those by the theory predicts suggested by Saeman. In addition, the effects of the ring dam fitted to the discharge end on the residence time and granulation improvement were investigated. As a result, with the drum set at the low angle, the observed residence times were shorter than the theory predicts. This is due to the level of the raw material tapering off as it reaches the discharge end. Thus, by newly considering angle ψ between the raw material surface and the drum mixer, the residence time was accurately estimated. Also, with the drum set the low angle, the ring dam fitted to the discharge end prevented any tapering, resulting in the longer residence time and greatly improved granulation.