Fertilizer composition and method for preparing the same
A method of producing a granulated and compacted fertilizer having incorporated micronutrients in which the granulated primary nutrient and micronutrients are mixed at smaller particle sizes before being compacted into a larger, easier to handle particle sizes.
1. A process for forming a compacted phosphate fertilizer granule, comprising:
producing a slurry of ammonium phosphate;
granulating the slurry to produce phosphate fertilizer granules;
sorting the fertilizer granules by size into optimally sized granules, oversized granules and undersized granules;
crushing the undersized granules to form a crushed granule stream; and
compacting the crushed granule stream to form a compacted phosphate fertilizer granule.
2. The process of claim 1 , wherein the compacted fertilizer granule has a compacted fertilizer granule diameter from about 2 mm to about 4 mm.
3. The process of claim 1 , wherein the optimally sized granules have an optimally sized granule diameter from about 2 mm to about 4 mm, the oversized granules have an oversized granule diameter greater than about 4 mm and the undersized granules have an undersized granule diameter less than about 2 mm.
4. The process of claim 1 , further comprising:
adding at least one additional nutrient to the undersized granules.
5. The process of claim 4 , wherein the at least one additional nutrient is selected from the group consisting of secondary nutrients, micronutrients and combinations thereof.
6. The process of claim 5 , wherein the at least one additional nutrient comprises one or more secondary nutrients selected from the group consisting of: ammonium sulfate, calcium sulfate, elemental sulfur, and combinations thereof.
7. The process of claim 5 , wherein the at least one additional nutrient comprises one or more micronutrients selected from the group consisting of: boron, copper, iron, manganese, molybdenum, zinc, complexes thereof, and combinations thereof.
8. The process of claim 5 , wherein the at least one additional nutrient has a nutrient particle size diameter from about 50 μm to about 150 μm.
9. The process of claim 1 , wherein the step of compacting the crushed granule stream, further comprises:
adding a binding agent to the crushed granule stream fertilizer mixture to improve adhesion of the compacted fertilizer granule.
10. The process of claim 1 , further comprising:
crushing the oversized granules; and
recycling the crushed, oversized granules to the granulation step.
11. The process of claim 10 , further comprising:
recycling a portion of the undersized granules to the granulation step.
12. The process of claim 1 , wherein the step of granulating the slurry, further comprises:
introducing the slurry into a rotating granulation drum to form a rolling bed of fertilizer granules; and
sparging the rolling bed of fertilizer granules with ammonia.
13. The process of claim 1 , wherein the phosphate fertilizer granules comprise monoammonium phosphate (MAP), diammonium phosphate (DAP), or combinations thereof.