# US 11,299,441 B2 · Calcium sulfate urea granules and methods for producing and using the same

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- Number: US 11,299,441 B2
- Document ID: US11299441B2
- Status: Granted
- Kind: B2
- Application number: 16/631,206
- Filed: 2018-07-19
- Published: 2020-05-14
- Granted: 2022-04-12
- Earliest claimed: 2017-07-21
- Assignees: Sabic Global Technologies B.V.
- Applicants: Sabic Global Technologies B.V.
- Inventors: Harri Kiiski; Andrew George Kells; Mohamed Akasha M. Khaleel; Nilkamal Bag
- Web page: https://patentgrep.com/patent/US11299441B2

## CPC

- C05G 5/12: Granules or flakes
- C05C 9/005: {Post-treatment}
- C05D 3/00: Calcareous fertilisers (C05D7/00 takes precedence)
- C05G 5/30: Layered or coated, e.g. dust-preventing coatings
- C05G 5/36: {layered or coated with sulfur}
- C05G: MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS (organic fertilisers containing added bacterial cultures, mycelia, or the like C05F11/08; organic fertilisers containing plant vitamins or hormones C05F11/10); FERTILISERS CHARACTERISED BY THEIR FORM
- C05C: NITROGENOUS FERTILISERS
- C05D: INORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C; FERTILISERS PRODUCING CARBON DIOXIDE

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 1)

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

### Claim 5 (depends on 1)

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

### Claim 6 (depends on 1)

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.

### Claim 7 (depends on 1)

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.

### Claim 8 (depends on 1)

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.

### Claim 9 (depends on 1)

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

### Claim 10 (depends on 1)

The process of claim 1, wherein the calcium sulfate urea adduct comprises CaSO4.4CO(NH)2.

### Claim 11 (depends on 1)

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.

### Claim 12 (depends on 1)

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.