PROCESS FOR REDUCING EMISSION OF DUST BY GRANULAR FERTILIZER COMPOSITIONS

• US 3,734,707 A
• Filed: 10/22/1970
• Issued: 05/22/1973
• Est. Priority Date: 10/22/1970
• Status: Expired due to Term

• Current Assignee: James E. Seymour
• Original Assignee: James E. Seymour
• Inventors: Seymour, James E.
• Primary Examiner(s): Friedman, Reuben
• Assistant Examiner(s): Barnes, Richard
• Application Number:
  US05/082,950
• Time in Patent Office: 943 Days
• Field of Search: 71/30,64DB,64E,54,58,59
• US Class Current: 71/30
• CPC Class Codes: B01J 2/28 using special binding agents
• CPC Class Codes: C05B 13/06 Alkali and alkaline earth meta- or polyphosphate fertilisers
• CPC Class Codes: C05B 7/00 Fertilisers based essentially on alkali or ammonium orthophosphates C05B11/00 takes precedence
• CPC Class Codes: C05G 3/20 for preventing the fertilisers being reduced to powder; Anti-dusting additives
• CPC Class Codes: C05G 5/30 Layered or coated, e.g. dust-preventing coatings

Abstract

Emission of air-borne particulates by granular fertilizer compositions upon being moved or handled is substantially reduced by spraying the granules with aqueous solutions of nitrogencontaining salts at the end of the cooling phase of the manufacturing procedure.

Claims

2. The process according to claim 1, wherein the aqueous solution of a nitrogen-containing salt is sprayed upon the fertilizer particulates at the discharge end of the air cooler.

3. The process according to claim 1 in which the aqueous solution contains ammonium orthophosphate and ammonium polyphosphate.

4. The process according to claim 3 in which the nitrogen-containing salts are present in the solution in amounts such that the total nitrogen content of the dissolved salts is at least 10 peRcent by weight of the solution.

5. The process according to claim 4 in which the aqueous solution of nitrogen-containing salts is applied at the rate of about 8 to 10 pounds of solution per ton of granulated fertilizer composition.

6. The process according to claim 1 in which the aqueous solution contains about 44 percent by weight ammonium nitrate and about 35 percent by weight urea.

7. The method of reducing the concentration of fertilizer dust in the atmosphere by the manufacture of fertilizer particulates resistant to emitting air-borne dust upon attrition, which comprises heat-drying ammoniated phosphoric acid, air-cooling the dried phosphatic fertilizer, and spraying the air-cooled fertilizer particulates with an aqueous solution of a nitrogen-containing salt to create an interparticle salt bridge between air-borne dust particles, and between air-borne dust particles and larger than air-borne particles.

8. The process according to claim 7 in which the aqueous solution contains a mixture of ammonium orthophosphate and ammonium polyphosphate.

9. The process according to claim 8 in which the nitrogen-containing salts are present in the solution in amounts such that the total nitrogen content of the dissolved salts is at least 10 percent by weight of the solution.

10. The process according to claim 9 in which the aqueous solution of nitrogen-containing fertilizers is applied at the rate of about 0.5 to 25 pounds of solution per ton of granulated fertilizer composition.

11. The process according to claim 7 in which the aqueous solution contains about 44 percent by weight ammonium nitrate and about 35 percent by weight urea.

12. In the manufacture of fertilizer compositions, wherein fertilizer particulates are heat dried, size classified and air cooled, the process for rendering the fertilizer compositions resistant to emitting air-borne dust upon attrition, which comprises spraying the fertilizer particulates with an aqueous solution of a nitrogen-containing fertilizer at the end of the air cooling phase of the manufacturing procedure to create an interparticle salt bridge between air-borne dust particles, and between air-borne dust particles and larger than air-borne particles.

13. The process according to claim 12, wherein the aqueous solution of a nitrogen-containing fertilizer is sprayed upon the fertilizer particulates at the discharge end of the air cooler.

14. The process according to claim 12 in which the aqueous solution contains ammonium orthophosphate and ammonium polyphosphate.

15. The process according to claim 14 in which the nitrogen-containing fertilizers are present in the solution in amounts such that the total nitrogen content of the dissolved fertilizers is at least 10 percent by weight of the solution.

16. The process according to claim 15 in which the aqueous solution of nitrogen-containing fertilizers is applied at the rate of about 8 to 10 pounds of solution per ton of granulated fertilizer composition.

17. The process according to claim 12 in which the aqueous solution contains about 44 percent by weight ammonium nitrate and about 35 percent by weight urea.

18. The method for reducing the concentration of fertilizer dust in the atmosphere by the manufacture of fertilizer particulates resistant to emitting air-borne dust upon attrition, which comprises heat-drying ammoniated phosphoric acid, air-cooling the dried phosphatic fertilizer, and spraying the air-cooled fertilizer particulates with an aqueous solution of a nitrogen-containing fertilizer.

19. The process according to claim 18 in which the aqueous solution contains a mixture of ammonium orthophosphate and ammonium polyphosphate.

20. The process according to claim 19 in which the nitrogen-containing fertilizers are present in the solution in amounts such that the total content of the dissolved fertilizers is at least 10 percent bY weight of the solution.

21. The process according to claim 20 in which the aqueous solution of nitrogen-containing fertilizers is applied at the rate of about 0.5 to 25 pounds of solution per ton of granulated fertilizer composition.

22. The process according to claim 18 in which the aqueous solution contains about 44 percent by weight ammonium nitrate and about 35 percent by weight urea.