Prodn. of granules with high bulk density - by granulation followed by tumbling in rotating drum

摘要

Prodn. of granules is carried out by granulating a soln., melt or suspension of the starting material at elevated temp. in a granulation zone contg. solid core particles; cooling the resulting hot granules; sieving the cooled granules to remove over- and under-size particles; crushing the oversize particles and recycling them together with the undersize particles to the granulation zone as core particles. The improvement is that the hot granules from the granulation zone or the product from the sieving stage are subjected to a uniform rolling motion in a rotating drum. The process is esp. applicable to fertilisers (e.g. Ca NH4 nitrate, urea or NH4NO3) or sulphur. The improvement provides more rounded granules with a higher bulk density.