Balling circuits and granulation loops

Multicircuit installations tend to dampen the effects of surging since the peak in production from one circuit may balance a valley in production from another. Surging can also be reduced by the use of a two-drum circuit [5] in which the correct proportion of seed nuclei is formed under controlled conditions in the first drum and then passed on to a second where more feed is added to grow the seeds to product size by layering. 

As with iron ore balling, the primary control of granulation is through the amount of liquid (or solution) phase present. Because of the presence of soluble consituents, the amount of water needed for granulation is roughly established by the chemical composition of the fertilizer. Operational controls are used for minor adjustment of the liquid phase in the granulator to stabilize the process and include adjustment of  

As the fundamental understanding of agglomeration circuits improves and suitable monitoring instrumentation is developed, simulation and automatic computer control [28] of these operations becomes possible. 

Characteristics of some fertilizer granulation drums. (Courtesy The A.J. Sackett and Sons Co.) 

Diameter (ft) Length (ft) Installed power (hp) rpm Approximate capacity (tons/h) 

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