CPC C05G 5/12 (2020.02) [C05C 9/005 (2013.01); C05D 3/00 (2013.01); C05G 5/30 (2020.02); C05G 5/36 (2020.02)] | 20 Claims |
1. A calcium sulfate urea (UCS) fertilizer granule comprising urea, calcium sulfate, and a calcium sulfate urea adduct, wherein the granule comprises 33 wt. % to 40 wt. % elemental nitrogen, 2 wt. % to 5 wt. % elemental calcium, 2 wt. % to 5 wt. % elemental sulfur, 0.1 wt. % to 50 wt. % ammonium sulfate, and less than 1 wt. % free moisture, wherein at least 30 wt. % of the urea in the granule is comprised in the calcium sulfate urea adduct.
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10. A fertilizer blend or compounded fertilizer comprising the UCS fertilizer granule of claim 1, and at least one additional component.
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14. A method of making the calcium sulfate urea (UCS) fertilizer granule of claim 1, the method comprising:
combining urea, calcium sulfate, and water to form an aqueous slurry, wherein urea is combined in excess of the stoichiometric ratio for production of a calcium sulfate urea adduct and the urea and calcium sulfate are combined in sufficient ratios to produce the aqueous slurry capable of producing a dried product containing 33 wt. % to 40 wt. % elemental nitrogen, 2 wt. % to 5 wt. % elemental calcium, 2 wt. % to 5 wt. % elemental sulfur;
mixing the aqueous slurry under conditions sufficient to produce a calcium sulfate urea adduct wherein at least 30 wt. % of the urea in the granule is comprised in the calcium sulfate urea adduct; and
removing at least a portion of the water from the aqueous slurry to form the calcium sulfate urea (UCS) fertilizer granule with less than 1 wt. % free moisture.
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20. A calcium sulfate urea (UCS) slurry comprising 12 to 16% water, urea, calcium sulfate, a calcium sulfate urea adduct, and ammonium sulfate in amounts such that when the slurry is dried, the dried slurry comprises 33 wt. % to 40 wt. % elemental nitrogen, 2 wt. % to 5 wt. % elemental calcium, and 2 wt. % to 5 wt. % elemental sulfur.
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