Prilling method
View Patent ↗A prilling method comprising the steps of: providing a molten first component, mixing at least a second component with the molten first component, reacting the components to form a shear-thinnable mixture; and prilling the shear-thinnable mixture wherein the prilling comprises mechanically agitating in the prill head to shear thin the shear-thinnable mixture sufficiently to permit prilling. The inventive method can be used to produce fertilizer product comprising ammonium sulfate nitrate.
1. A method to prill a shear-thinnable mixture comprising the steps of:
a) providing a molten first component;
b) mixing at least a second component with said molten first component;
c) reacting said components at a temperature and for a time sufficient to form a shear-thinnable mixture having a viscosity, which decreases with increasing shear rate;
d) mechanically agitating said shear-thinnable mixture by an agitator in a prill head under conditions such that the entire liquid volume in said prill head is swept by said agitator to shear thin said shear-thinnable mixture; and permitting said shear-thinned mixture to flow through holes in said prill head under the influence of a force selected from the group consisting of static pressure and centrifugal force.
2. The method according to claim 1 wherein said shear-thinnable mixture is a melt slurry.
3. The method according to claim 1 wherein said first component is ammonium nitrate and said second component is ammonium sulfate.
4. The method according to claim 3 wherein said shear-thinnable mixture further comprises micronutrients.
5. The method according to claim 1 wherein said shear-thinnable mixture comprises no more than about 2 weight percent water.
6. The method according to claim 1 wherein said prill head is one of a rotating bucket with a stationary blade, a stationary bucket with rotating scrappers and blades, and an agitated pressurized nozzle assembly.
7. The method according to claim 1 wherein said prill head is wiped with surface-wiping blades.
8. The method according to claim 7 wherein said first component is ammonium nitrate and said second component is ammonium sulfate.
9. The prilling method according to either claim 3 or claim 8 , wherein the reaction time is about 10 minutes to about 15 minutes.
10. The prilling method according to either claim 3 or claim 8 , wherein the reaction temperature is at least about 180° C. to about 200° C.
11. The prilling method according to either claim 3 or claim 8 , wherein the ammonium nitrate and the ammonium sulfate are present in equimolar amounts.
12. The method according to claim 7 wherein said shear-thinnable mixture comprises no more than about 2 weight percent water.
13. The method according to claim 7 wherein said shear-thinnable mixture further comprises micronutrients.