Process for granulating mineral fertilisers

摘要

Process for granulating mineral fertilisers from melts, which consists in dividing the melt of mineral fertiliser into drops in the comminution and crystallisation zone of the melt drops when they fall freely in the crystallisation zone, giving granules. The dividing and crystallisation processes are accompanied by the formation of dust-like particles of mineral fertiliser. The processing steps of the melt which have been indicated are carried out in air as a medium, which circulates in a circulation containing a crystallisation zone and purification and cooling zone or crystallisation zone, comminution zone and purification and cooling zone, the air passing through the zones indicated in the sequence given. As the air passes through the crystallisation zone or the crystallisation zone and comminution zone, it is warmed and takes up the particulate particles of the mineral fertiliser, while, when the air flows through the purification and cooling zone, it is freed from the dust-like particles by being sprayed with a finely-divided washing liquid, cooled and compressed. The extent of the spraying density (q) in the case of the washing liquid is a function of the speed (u) of the air in the crystallisation zone. <IMAGE>