Process for preparing ammonium sulfate nitrate

Patent metadata

Field	Value
Publication number	US-9464008-B2
Application number	US-201313743090-A
Country	US
Kind code	B2
Filing date	Jan 16, 2013
Priority date	Feb 1, 2012
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

Ammonium sulfate nitrate double salts may be produced using a process that result in complete or nearly complete conversion to the 2:1 double salt. In some embodiments, the disclosure pertains to methods of controlling moisture content during the production process.

First claim

We claim:

1. A method of producing a solid ammonium sulfate nitrate composition comprising the step of:
solidifying a melt slurry including ammonium sulfate and ammonium nitrate in a granulation bed to form the solid ammonium sulfate nitrate composition comprising ammonium sulfate nitrate 2:1 double salt, wherein the melt slurry has a molar ratio of ammonium sulfate to ammonium nitrate of about 0.9:1 to about 1.1:1, wherein the granulation bed has an operating temperature of 90° C. to 120° C. and the solid ammonium sulfate nitrate composition has a moisture content of between 0.4 wt. % and 2.0 wt. % wherein the solid ammonium sulfate nitrate composition is primarily in the form of the ammonium sulfate nitrate 2:1 double salt and includes less than about 7 wt. % of unreacted ammonium nitrate and ammonium sulfate nitrate 3:1 double salt.

2. The method of claim 1 , wherein the granulation bed has an operating temperature of 90° C. to 105° C.

3. The method of claim 1 , wherein said solidifying step further comprises adding steam to the granulation bed.

4. The method of claim 1 , wherein said solidifying step further comprises spraying an aqueous solution onto the granulation bed.

5. The method of claim 1 , wherein said solidifying step further comprises selectively modifying a rate of air flow through the granulation bed.

6. The method of claim 1 , wherein said solidifying step further comprises:
adding steam to the granulation bed; and
selectively modifying a rate of air flow through the granulation bed.

7. A method of producing a solid ammonium sulfate nitrate composition including ammonium sulfate nitrate 2:1 double salt, said method comprising the steps of:
adding a melt slurry including ammonium sulfate and ammonium nitrate to a granulation device, wherein the melt slurry has a molar ratio of ammonium sulfate to ammonium nitrate of about 0.9:1 to about 1.1:1;
adding an amount of supplemental ammonia to the granulation device in addition to ammonia provided in the melt slurry;
solidifying the melt slurry in the granulation device in the presence of the supplemental ammonia to form a solid granule mixture including ammonium sulfate nitrate 2:1 double salt, wherein the solid ammonium sulfate nitrate composition is primarily in the form of the ammonium sulfate nitrate 2:1 double salt and includes less than about 7 wt. % of unreacted ammonium nitrate and ammonium sulfate nitrate 3:1 double salt.

8. The method of claim 7 , wherein said adding steps further comprise, respectively:
adding the melt slurry to a material bed of the granulation device; and
adding the supplemental ammonia to the material bed of the granulation device.

9. The method of claim 7 , wherein the solidification device is a granulation device, and said adding step further comprises:
adding the supplemental ammonia to a material bed of a drying device downstream of the granulation device.

10. A method of producing a solid ammonium sulfate nitrate composition, said method comprising the steps of:
adding a melt slurry including ammonium sulfate and ammonium nitrate to a granulation bed of a granulation device wherein the melt slurry has a molar ratio of ammonium sulfate to ammonium nitrate of about 0.9:1 to about 1.1:1;
solidifying the melt slurry in the granulation bed of the granulation device to form the solid ammonium sulfate nitrate composition, including ammonium sulfate nitrate 2:1 double salt;
drying the solid mixture in a drying device such that a moisture content of the solid ammonium sulfate nitrate composition in the drying device is between 0.4 wt. % and 1.5 wt. %, wherein the solid ammonium sulfate nitrate composition is primarily in the form of the ammonium sulfate nitrate 2:1 double salt and include less than about 7 wt. % of unreacted ammonium nitrate and ammonium sulfate nitrate 3:1 double salt.

11. The method of claim 10 , wherein said controlling step further comprises selectively modifying a rate of air flow through the drying device.

12. A method of producing a solid ammonium sulfate nitrate composition including ammonium sulfate nitrate 2:1 double salt, said method comprising the steps of:
solidifying a melt slurry including ammonium sulfate and ammonium nitrate in a granulation device to form solid ammonium sulfate nitrate granules including ammonium sulfate nitrate 2:1 double salt, wherein the melt slurry has a molar ratio of ammonium sulfate to ammonium nitrate of about 0.9:1 to about 1.1:1, wherein the solid ammonium sulfate nitrate has a moisture content of 0.4 to 2.0 wt. %, wherein the solid ammonium sulfate nitrate granules include less than about 7 wt. % of unreacted ammonium nitrate and ammonium sulfate nitrate 3:1 double salt.

13. The method of claim 12 , wherein the solid ammonium sulfate nitrate has a moisture content between 0.5 and 1.5 wt. %.

14. The method of claim 1 , wherein the solid ammonium sulfate nitrate composition includes less than about 3 wt. % of ammonium nitrate and ammonium sulfate nitrate 3:1 double salt.

15. The method of claim 12 , wherein the solid ammonium sulfate nitrate granules include less than about 3 wt. % of unreacted ammonium nitrate and ammonium sulfate nitrate 3:1 double salt.

16. The method of claim 1 , wherein the granulation bed has an operating temperature of 90° C. to 105° C., the solid ammonium sulfate nitrate composition has a moisture content between 0.5 wt. % and 2.0 wt. %, and the solid ammonium sulfate nitrate composition includes less than about 3 wt. % of unreacted ammonium nitrate and ammonium sulfate nitrate double salt.

17. The method of claim 7 , wherein the amount of supplemental ammonium is sufficient to raise a pH of the solid ammonium sulfate nitrate composition exiting the granulation bed to a pH of about 5.2.

Assignees

• Honeywell Int Inc

Inventors

• Barthe Stephanie C
• Kweeder James A
• Azimova Maria A
• Wissinger Raymond G
• Pace Christopher B
• Mcgill Joshua H
• Cochran Keith D
• Howes Andrew J

Classifications

• C05C3/00

  Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor · CPC title

• C05C1/00 Primary

  Ammonium nitrate fertilisers · CPC title

• C05C1/02 Primary

  Granulation (apparatus B01J2/00); Pelletisation; Stabilisation; Colouring · CPC title

• C01C1/248

  Preventing coalescing or controlling form or size of the crystals · CPC title

• C05C3/005

  Post-treatment · CPC title