Volume 2, Issue 7 (July 2005)
The Effect of Dispersant Solubility, Dispersant Dosage, Granule Diameter, and Dome Versus Radial Extrusion on Granule Spontaneity of Disintegration and Resistance to Attrition
Dissolution rate of 16 sulfonated dispersants was measured in both water and 32-0-0 liquid fertilizer. Two dispersants, BNA and UCA, having different dissolution rates, were used to granulate a 70 % Amicarbazone formulation. Extrusions were made on a MG-55 Multigranulator using both the dome and radial modes with 0.8 mm and 1.0 mm screens. BNA and UCA were included at levels of 5, 10, and 15 % of the formulation. The remaining 14 dispersants were compared at fixed levels of 10 % using only the 0.8 mm screen and dome mode. Premix water requirements varied according to dispersant chemistry. Granule disintegration was measured in hard water by number of inversions, ASTM E1945, and CIPAC MT-174. High level of dispersant, slow dissolution rate of dispersant, and larger diameter granules lead to reduced disintegration rate in water. In addition to these factors, disintegration in 32-0-0 was further affected by porosity of the granule.