Method for producing ammonium sulfate nitrate

1. A method of producing an ammonium sulfate nitrate 1:2 double salt, the method comprising:

combining an aqueous solution of ammonium sulfate, a nitric acid solution, and a source of ammonia in an aqueous solution to form a reaction mixture;

heating the reaction mixture to a temperature from about 160° C. to 175° C.;

allowing the reaction mixture to undergo a reaction to form an intermediate mixture comprising ammonium nitrate, ammonium sulfate, and water, wherein the intermediate mixture includes from about 15 wt. % to about 20 wt. % water;

heating the intermediate mixture to a finishing temperature from greater than 175° C. to about 190° C.;

holding the intermediate mixture at the finishing temperature to remove water from the intermediate mixture to form a molten salt mixture; and

forming a product by solidifying the molten salt mixture, wherein the product comprises an ammonium sulfate nitrate 1:2 double salt, wherein the reaction mixture includes a molar ratio of ammonia to nitric acid that is about 1.3:1.

2. A method of producing an ammonium sulfate nitrate 1:2 double salt, the method comprising:

combining an aqueous solution of ammonium sulfate, a nitric acid solution, and a source of ammonia in an aqueous solution to form a reaction mixture;

heating the reaction mixture to a temperature from about 160° C. to 175° C.;

allowing the reaction mixture to undergo a reaction to form an intermediate mixture comprising ammonium nitrate, ammonium sulfate, and water, wherein the intermediate mixture includes from about 15 wt. % to about 20 wt. % water;

heating the intermediate mixture to a finishing temperature from greater than 175° C. to about 190° C.;

holding the intermediate mixture at the finishing temperature to remove water from the intermediate mixture to form a molten salt mixture; and

forming a product by solidifying the molten salt mixture, wherein the product comprises an ammonium sulfate nitrate 1:2 double salt, wherein combining the aqueous solution of ammonium sulfate, the nitric acid solution, and the source of ammonia in an aqueous solution to form a reaction mixture comprises combining the aqueous solution of ammonium sulfate solution, the nitric acid solution, and an ammonium hydroxide solution.

3. The method of claim 2 , wherein said combining the aqueous solution of ammonium sulfate, the nitric acid solution, and the source of ammonia in an aqueous solution to form a reaction mixture further comprises adding solid ammonium sulfate.

4. The method of claim 1 , wherein the product has a water content of about 0.4 wt. % to about 1 wt. %.

5. The method of claim 1 , wherein holding the intermediate mixture at the finishing temperature to remove water from the intermediate mixture to form molten salt mixture comprises:

removing substantially all of the water from the intermediate mixture; and

adding a final amount of water back into molten salt mixture.

6. A method of producing an ammonium sulfate nitrate 1:2 double salt, the method comprising:

combining an aqueous solution of ammonium sulfate, a nitric acid solution, and a source of ammonia to form an aqueous reaction mixture;

heating the aqueous reaction mixture to a temperature of about 175° C.;

reacting the nitric acid and the source of ammonia in the presence of the ammonium sulfate to form an aqueous solution of ammonium nitrate and ammonium sulfate, wherein the aqueous solution of ammonium nitrate and water includes from about 15 wt. % to about 20 wt. % water;

heating the aqueous solution to a finishing temperature of about 185° C.;

reducing the water content of the aqueous solution of ammonium nitrate and ammonium sulfate by holding the aqueous solution at the finishing temperature to form a molten salt mixture; and

forming a product by solidifying the molten salt mixture, wherein the product comprises an ammonium sulfate nitrate 1:2 double salt.

7. The method of claim 6 , wherein combining the aqueous solution of ammonium sulfate, the nitric acid solution, and the source of ammonia to form an aqueous reaction mixture comprises adding the source of ammonia in stoichiometric excess with respect to the nitric acid.

8. The method of claim 6 , wherein combining the aqueous solution of ammonium sulfate, the nitric acid solution, and the source of ammonia to form an aqueous reaction mixture further comprises adding solid ammonium sulfate.

9. The method of claim 6 , wherein the product has a water content of about 0.4 wt. % to about 1 wt. %.

10. The method of claim 6 , wherein reducing the water content of the aqueous solution of ammonium nitrate and ammonium sulfate to form the molten salt mixture comprises:

removing about all of the water from the aqueous solution; and

adding a final amount of water back into the molten salt mixture.

11. The method of claim 1 , wherein the product has a weight content of ammonium sulfate nitrate 1:2 double salt of at least about 60 weight percent and an ammonium sulfate nitrate 1:3 double salt weight content of less than about 5 wt. %.

12. The method of claim 6 , wherein the product has a weight content of ammonium sulfate nitrate 1:2 double salt of at least about 60 weight percent and an ammonium sulfate nitrate 1:3 double salt weight content of less than about 5 wt. %.

13. The method of claim 1 , wherein the product has a combined content of ammonium sulfate nitrate 1:3 double salt and unreacted ammonium nitrate of less than about 5 wt. %.

14. The method of claim 1 , wherein the product has an ammonium sulfate nitrate 1:3 double salt weight content of less than about 1 wt. %.

15. The method of claim 6 , wherein the product has an ammonium sulfate nitrate 1:3 double salt weight content of less than about 1 wt. %.

16. A method of producing an ammonium sulfate nitrate 1:2 double salt, the method comprising:

combining an aqueous solution of ammonium sulfate, a nitric acid solution, and a source of ammonia in an aqueous solution to form a reaction mixture;

heating the reaction mixture to a temperature from about 160° C. to 175° C.;

allowing the reaction mixture to undergo a reaction to form an intermediate mixture comprising ammonium nitrate, ammonium sulfate, and water, wherein the intermediate mixture includes from about 15 wt. % to about 20 wt. % water;

heating the intermediate mixture to a finishing temperature is from 180° C. to 190° C.;

holding the intermediate mixture at the finishing temperature to remove water from the intermediate mixture to form a molten salt mixture; and

forming a product by solidifying the molten salt mixture, wherein the product comprises an ammonium sulfate nitrate 1:2 double salt.

17. A method of producing an ammonium sulfate nitrate 1:2 double salt, the method comprising:

combining an aqueous solution of ammonium sulfate, a nitric acid solution, and a source of ammonia in an aqueous solution to form a reaction mixture;

heating the reaction mixture to a temperature from about 160° C. to 175° C.;

allowing the reaction mixture to undergo a reaction to form an intermediate mixture comprising ammonium nitrate, ammonium sulfate, and water, wherein the intermediate mixture includes from about 15 wt. % to about 20 wt. % water;

heating the intermediate mixture to a finishing temperature is from about 185° C. to about 190° C.;

holding the intermediate mixture at the finishing temperature to remove water from the intermediate mixture to form a molten salt mixture; and

forming a product by solidifying the molten salt mixture, wherein the product comprises an ammonium sulfate nitrate 1:2 double salt.

18. The method of claim 6 , wherein the wherein the aqueous solution includes a molar ratio of ammonium sulfate to nitric acid that is about 1:1.

19. The method of claim 2 , wherein the product has a water content of about 0.4 wt. % to about 1 wt. %.

20. The method of claim 16 , wherein the product has a water content of about 0.4 wt. % to about 1 wt. %.

21. The method of claim 17 , wherein the product has a water content of about 0.4 wt. % to about 1 wt. %.

22. The method of claim 2 , wherein holding the intermediate mixture at the finishing temperature to remove water from the intermediate mixture to form molten salt mixture comprises:

removing substantially all of the water from the intermediate mixture; and

adding a final amount of water back into molten salt mixture.

23. The method of claim 16 , wherein holding the intermediate mixture at the finishing temperature to remove water from the intermediate mixture to form molten salt mixture comprises:

removing substantially all of the water from the intermediate mixture; and

adding a final amount of water back into molten salt mixture.

24. The method of claim 17 , wherein holding the intermediate mixture at the finishing temperature to remove water from the intermediate mixture to form molten salt mixture comprises:

removing substantially all of the water from the intermediate mixture; and

adding a final amount of water back into molten salt mixture.

25. The method of claim 2 , wherein the product has a weight content of ammonium sulfate nitrate 1:2 double salt of at least about 60 wt. % and an ammonium sulfate nitrate 1:3 double salt weight content of less than about 5 wt. %.

26. The method of claim 16 , wherein the product has a weight content of ammonium sulfate nitrate 1:2 double salt of at least about 60 wt. % and an ammonium sulfate nitrate 1:3 double salt weight content of less than about 5 wt. %.

27. The method of claim 17 , wherein the product has a weight content of ammonium sulfate nitrate 1:2 double salt of at least about 60 wt. % and an ammonium sulfate nitrate 1:3 double salt weight content of less than about 5 wt. %.

28. The method of claim 1 , wherein the product has a combined content of ammonium sulfate nitrate 1:3 double salt and unreacted ammonium nitrate of less than about 5 wt. %.

29. The method of claim 16 , wherein the product has a combined content of ammonium sulfate nitrate 1:3 double salt and unreacted ammonium nitrate of less than about 5 wt. %.

30. The method of claim 17 , wherein the product has a combined content of ammonium sulfate nitrate 1:3 double salt and unreacted ammonium nitrate of less than about 5 wt. %.

31. The method of claim 2 , wherein the product has an ammonium sulfate nitrate 1:3 double salt weight content of less than about 1 wt. %.

32. The method of claim 16 , wherein the product has an ammonium sulfate nitrate 1:3 double salt weight content of less than about 1 wt. %.

33. The method of claim 17 , wherein the product has an ammonium sulfate nitrate 1:3 double salt weight content of less than about 1 wt. %.