Acid treatment for fertilizers to increase zinc solubility and availability

Patent metadata

Field	Value
Publication number	US-10487016-B2
Application number	US-201615235499-A
Country	US
Kind code	B2
Filing date	Aug 12, 2016
Priority date	Aug 12, 2015
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

Methods and system for increasing the water solubility and availability of zinc in granular fertilizers using acid treatments. The treatment of granular fertilizers with an acidic solution increases an amount of water-soluble zinc, which in turn, increases the efficiency of zinc uptake and reduces the costs and equipment otherwise needed to mitigate zinc deficiencies.

First claim

The invention claimed is:

1. A granulated fertilizer product comprising:
a plurality of acidified fertilizer granules including a plurality of base granules, each base granule containing a macronutrient source and a source of zinc incorporated into the macronutrient source,
wherein each base fertilizer granule is acidified by direct application of a liquid acidifying agent to an outer surface of the base fertilizer granule in an amount to increase zinc solubility thereby increasing availability of zinc for plant uptake.

2. The granulated fertilizer product of claim 1 , wherein the acidifying agent is selected from the group consisting of: citric acid, oxalic acid, sulfamic acid, cyclohexanediaminepentaacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediaminedi-o-hydroxyphenylacetic acid, ethylenediamintetraacetic acid, ethylene glycol bis(2-aminoethyl ether) tetraacetic acid, hydroxyethylenediaminetriacetic acid, nitrilo-triacetic acid, pyrophosphoric acid, triphosphoric acid, sulfuric acid, nitric acid, acetic acid, phosphoric acid, and combinations thereof.

3. The granulated fertilizer product of claim 1 , wherein the acidifying agent is applied as an acidic solution at concentrations ranging from about 0.1% to the solubility limit of the acidic solution.

4. The granulated fertilizer product of claim 1 , wherein a target moisture content of the fertilizer product is from about 0.5 wt % to about 6.5 wt %.

5. The granulated fertilizer product of claim 1 , further comprising:
a beneficial agricultural additive applied to the base fertilizer granules, the beneficial agricultural additive being selected from the group consisting of: a secondary nutrient, a micronutrient a bio-stimulant, and combinations thereof.

6. The granulated fertilizer product of claim 5 , wherein the secondary nutrient is selected from the group consisting of: a source of sulfur, a source of calcium, a source of magnesium, and combinations thereof.

7. The granulated fertilizer product of claim 5 , wherein the micronutrient is selected from the group consisting of: a source of iron, a source of manganese, a source of zinc, a source of copper, a source of boron, a source of molybdenum, a source of chlorine, and combinations thereof.

8. The granulated fertilizer product of claim 1 , wherein the liquid acidifying agent is present in an amount of about 0.1% to about 10 wt % of a total weight of each granule.

9. The granulated fertilizer product of claim 1 , wherein the source of zinc is selected from the group consisting of: zinc sulfate heptahydrate, zinc sulfate monohydrate, zinc oxysulfate, zinc oxide, zinc chloride, zinc nitrate, ZnEDTA, and combinations thereof.

10. The granulated fertilizer product of claim 1 , wherein the availability of the zinc for plant uptake is increased by chelation of the zinc by the acidifying agent.

11. The granulated fertilizer product of claim 1 , wherein the availability the zinc for plant uptake is increased by complex formation between the macronutrient and the zinc.

12. The granulated fertilizer product of claim 1 , wherein availability of the zinc for plant uptake is increased by converting a water insoluble zinc source to a water soluble zinc source.

13. A method for increasing zinc solubility and consequently availability in fertilizer granules, comprising:
providing a granular fertilizer product comprising a plurality of base fertilizer granules, each base fertilizer granule formed of a macronutrient source and a source of zinc incorporated into the base fertilizer granule; and
applying a liquid acidifying agent directly to a surface of the macronutrient source of the base fertilizer granules in an amount to increase zinc solubility thereby increasing availability of zinc for plant uptake.

14. The method of claim 13 , wherein the acidifying agent comprises an acidic solution, and wherein the step of applying the acidifying agent, further comprises:
spraying the acidic solution onto the base fertilizer granules within a treatment vessel.

15. The method of claim 14 , wherein the treatment vessel is selected from the group consisting of: a tumbling drum, a tumbling bed, a flighted drum, a flighted bed, and a fluidized bed.

16. The method of claim 14 , wherein the acidic solution is applied at a temperature in the range of about 32° F. to about 800° F.

17. The method of claim 14 , wherein the acidic solution is a water-based solution and wherein the water-based solution is applied at a temperature in the range of about 70° F. to about 170° F.

18. The method of claim 13 , wherein the acidifying agent is selected from the group consisting of: citric acid, oxalic acid, sulfamic acid, cyclohexanediaminepentaacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediaminedi-o-hydroxyphenylacetic acid, ethylenediamintetraacetic acid, ethylene glycol bis(2-aminoethyl ether) tetraacetic acid, hydroxyethylenediaminetriacetic acid, nitrilo-triacetic acid, pyrophosphoric acid, triphosphoric acid, sulfuric acid, nitric acid, acetic acid, phosphoric acid, and combinations thereof.

19. The method of claim 14 , wherein the acidic solution is applied at concentrations ranging from about 0.1% to the solubility limit of the acidic solution.

20. The method of claim 13 , further comprising:
reheating the base fertilizer granules prior to application of the acidifying agent.

21. The method of claim 20 , wherein a target surface temperature of the base fertilizer granules is from about 50° F. to about 250° F.

22. The method of claim 20 , wherein a target moisture content of the fertilizer product is from about 0.5 wt % to about 6.5 wt %.

23. The method of claim 13 , further comprising:
adding a beneficial agricultural additive to the surface of the fertilizer product, the beneficial agricultural additive being selected from the group consisting of: a secondary nutrient, a micronutrient a bio-stimulant, and combinations thereof.

24. The method of claim 23 , wherein the secondary nutrient is selected from the group consisting of: a source of sulfur, a source of calcium, a source of magnesium, and combinations thereof.

25. The method of claim 23 , wherein the micronutrient is selected from the group consisting of: a source of iron, a source of manganese, a source of zinc, a source of copper, a source of boron, a source of molybdenum, a source of chlorine, and combinations thereof.

26. The method of claim 13 , wherein the acidifying agent is applied in an amount of about 0.1% to about 10 wt % of a total weight of the fertilizer product.

27. The method of claim 13 , further comprising:
agitating the base fertilizer granules to induce mechanical interaction between the base fertilizer granules.

28. The method of claim 13 , further comprising:
removing extra moisture from the fertilizer product with acidifying agent thereon.

29. The method of claim 13 , wherein the zinc is supplied by a zinc source selected from the group consisting of: zinc sulfate heptahydrate, zinc sulfate monohydrate, zinc oxysulfate, zinc oxide, zinc chloride, zinc nitrate, ZnEDTA, and combinations thereof.

30. The method of claim 13 , wherein the availability of the zinc for plant uptake is increased by chelation of the zinc.

31. The method of claim 13 , wherein the availability of the zinc for plant uptake is increased by

Assignees

• Mosaic Co

Inventors

• Mclaughlin Michael John
• Degryse Jozefien Louisa Elvire
• Baird Roslyn Jane
• da Silva Rodrigo Coqui
• Baylor Bryan Todd
• Peacock Lawrence Alan

Classifications

• C05B17/00 Primary

  Other phosphatic fertilisers, e.g. soft rock phosphates, bone meal · CPC title

• C05G5/36 Primary

  layered or coated with sulfur · CPC title

• C05G3/44

  for affecting solubility · CPC title

• B01J2/12

  in rotating drums · CPC title

• C05C1/00

  Ammonium nitrate fertilisers · CPC title