Drum granulation of NPK fertilizers

• Published in: Powder technology Vol. 107; no. 3; pp. 282 - 288
• Main Authors: Walker, G.M, Holland, C.R, Ahmad, M.N, Fox, J.N, Kells, A.G
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.02.2000; Elsevier
• Subjects: Applied sciences; Binder viscosity; Chemical industry and chemicals; Drum granulation; Exact sciences and technology; Fertilisers; Industrial chemicals; NPK fertilizer; Size distribution; Size distribution; NPK fertilizer; Binder viscosity; Drum granulation; Particle size distribution; Granulated fertilizer; Granulation; Compound fertilizer; Rotating cylinder; Manufacturing; Experimental study; Grain size distribution
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/S0032-5910(99)00253-3

Nitrate-based NPK fertilizer was granulated in a bench scale drum granulation unit. The initial fertilizer possessed a particle size distribution similar to those in industrial granulation units. In this work, three factors are identified affecting the degree of fertilizer granulation, these are solution to solid phase ratio, the binder viscosity and the optimal rotation speed of the drum. Experimental results indicate that a critical solution to solid phase ratio is required for an increase in granulation in terms of mass median diameter. The saturated solution viscosity in this system was measured and correlated well to binder viscosity granulation theory with the critical Stokes number calculated at 700. The optimum rotation speed for flighted and unflighted drums correlated with the Froude number relationship for full scale granulation units.