Abstract
If the“crumbs”of agglomerates are formed in a floclike mass of damp powders, the agglomerate growth during the early stage of tumbling agglomeration may be analyzed from the stand point of appearance-disappearance process. In this case, if the coalescene of agglomerates is assumed to be the only pravailing mechanism, a rate equation of agglomerate growth which shows the first order process can be introduced.
It is derived from the above-mentioned consideration that, when agglomerate size data is fitted for the Rosin-Rammler type distribution (i. e., Rm=100exp(-Bx3)), the correlation for the arithmetic mean size of agglomerates, on the mass basis, to cumulative drum revolutions is represented by an exponential function. In the case of damp powders of pulverized limestone having a uniform size range by sieving, the rate constant, kn, of agglomerate growth is extremely sensitive to the moisture content more than about 60 volume %. This marked dependence of the rate constant on moisture content is similar to the data of Kapur et al. for comparatively finer limestone powders and for lower moisture contents. Furthermore, it is observed that the combined relation, (1-ε)φv, between void fraction and volume shape factor for the agglomerates encountered in the agglomerate size analysis is experimentally independent of cumulative drum revolutions.
