Calcium sulfate urea granules and methods for producing and using the same

Patent metadata

Field	Value
Publication number	US-11299441-B2
Application number	US-201816631206-A
Country	US
Kind code	B2
Filing date	Jul 19, 2018
Priority date	Jul 21, 2017
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

A calcium sulfate urea (UCS) fertilizer granule and methods for making and using the same are disclosed. The granule can include urea, calcium sulfate, and a calcium sulfate urea adduct, wherein a portion of the surface of the calcium sulfate urea adduct includes a layer comprising urea, calcium sulfate, or calcium sulfate urea adduct, or any combination or all thereof.

First claim

The invention claimed is:

1. A process to prepare a calcium sulfate urea fertilizer granule the process comprising:
combining urea, hydrated or anhydrous calcium sulfate, and steam under conditions sufficient to form an aqueous solution comprising water, urea, and calcium sulfate, wherein the urea is solubilized in the aqueous solution;
mixing the aqueous solution under conditions sufficient to produce a wet fertilizer granule comprising a calcium sulfate urea adduct and water; and
removing at least a portion of the water from the wet fertilizer granule to form the calcium sulfate urea granule,
wherein the calcium sulfate urea fertilizer granule formed comprises urea, calcium sulfate, and the calcium sulfate urea adduct, and
wherein a portion of the surface of the calcium sulfate urea adduct includes a layer comprising urea, calcium sulfate, or the calcium sulfate urea adduct, or any combination or all thereof.

2. The process of claim 1 , wherein the step (a) conditions comprise a temperature of 85° C. to 120° C.

3. The process of claim 1 , wherein the wet fertilizer granule in step (b) includes a sufficient amount of water such that the composition is formable.

4. The process of claim 1 , wherein step (c) comprises a temperature of 80° C. up to 100° C.

5. The process of claim 1 , wherein at least 30% of the urea from step (a) is converted to the calcium sulfate urea adduct.

6. The process of claim 1 , wherein the calcium sulfate urea fertilizer granule formed comprises 20 wt. % to 44 wt. % elemental nitrogen, 4.5 wt. % to 15 wt. % elemental calcium, and 4 wt. % to 12 wt. % elemental sulfur.

7. The process of claim 1 , wherein the calcium sulfate urea fertilizer granule formed comprises 26.5 to 27.5 wt. % elemental nitrogen, about 8.5 to 10.5 wt. % elemental calcium, and 6.5 to 8.5 wt. % elemental sulfur.

8. The process of claim 1 , wherein the calcium sulfate urea fertilizer granule formed comprises 32.5 wt. % to 33.5 wt. % elemental nitrogen, 4.5 wt. % to 5.5 wt. % elemental calcium, 4.5 wt. % to 5.5 wt. % elemental sulfur.

9. The process of claim 1 , wherein the calcium sulfate urea fertilizer granule formed comprises less than 1 wt. % free moisture.

10. The process of claim 1 , wherein the calcium sulfate urea adduct comprises CaSO 4 .4CO(NH) 2 .

11. The process of claim 1 , wherein the calcium sulfate urea fertilizer granule formed has a crush strength of 2 kg/granule to 5 kg/granule.

12. The process of claim 1 , wherein the calcium sulfate urea fertilizer granule formed comprises calcium sulfate urea adduct particles, urea particles, and calcium sulfate particles.

Assignees

• Sabic Global Technologies Bv

Inventors

• Kiiski Harri
• Kells Andrew George
• Khaleel Mohamed Akasha M
• Bag Nilkamal

Classifications

• C05D3/00

  Calcareous fertilisers (C05D7/00 takes precedence) · CPC title

• C05G5/30

  Layered or coated, e.g. dust-preventing coatings · CPC title

• C05G5/36

  layered or coated with sulfur · CPC title

• C05C9/005 Primary

  Post-treatment · CPC title

• C05G5/12 Primary

  Granules or flakes · CPC title