# US 10,870,609 B2 · Reactive inorganic coatings for agricultural fertilizers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,609 B2 - Document ID: US10870609B2 - Status: Granted - Kind: B2 - Application number: 16/543,071 - Filed: 2019-08-16 - Published: 2020-02-20 - Granted: 2020-12-22 - Earliest claimed: 2018-08-16 - Assignees: Anuvia Plant Nutrients Corporation - Applicants: Anuvia Plant Nutrients Corporation - Inventors: Sanford A. Siegel; Jeffrey C. Burnham - Web page: https://patentgrep.com/patent/US10870609B2 ## CPC - C05G 5/30: Layered or coated, e.g. dust-preventing coatings - C05C 1/02: Granulation (apparatus B01J2/00); Pelletisation; Stabilisation; Colouring - C05D 9/02: containing trace elements - C05F 3/00: Fertilisers from human or animal excrements, e.g. manure - C05F 5/002: {Solid waste from mechanical processing of material, e.g. seed coats, olive pits, almond shells, fruit residue, rice hulls} - C05G 5/12: Granules or flakes - Y02A 40/20: Fertilizers of biological origin, e.g. guano or fertilizers made from animal corpses - Y02P 20/145: the feedstock being materials of biological origin - 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 - C05F: ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE - Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract The invention relates to a coated granular fertilizer, preferably wherein granules are sulfate-based or phosphate-based. When sulfate based granules, as in ammonium sulfate, the coating substance is an inorganic salt of alkaline earth elements, preferably calcium, such that when applied to the surface of fertilizers, forms calcium sulfate, preferably a calcium sulfate-dihydrate, as a protective coating. For a reactive coating of a thiosulfate, free sulfuric acid present on the granule reacts to provide an elemental sulfur coating. For ammonium phosphate-based granules, coatings may comprise compounds of Ca++, Al+++ and/or Fe+++ salts thereby forming a calcium, an aluminum, an iron, or mixed cation phosphate protective coating. Thiosulfate is also effective with phosphate based granules which are manufactured with sulfuric acid. Granules coated according to the disclosure have advantageous properties as the coating can be applied in a specified and sparing manner due to its tendency to adhere to surfaces during the reaction. Coated fertilizer granules of the disclosure are also advantageous in that, with regard to the applied amount of coating, they provide increased resistance to dusting in long term warehouse storage, to moisture uptake and to oxidative heating. Coating components also add nutrients to plants that can provide nutrients over a longer period of time such as a slow-release characteristic. ## Claims ### Claim 1 A method of coating fertilizer granules comprising: providing fertilizer granules containing organic material and an acid; contacting the fertilizer granules at an acidic pH with an inorganic compound, wherein the inorganic compound chemically reacts with the acid of the fertilizer granules forming a coating on the fertilizer granules, wherein the coating comprises aluminum, iron, aluminum-calcium sulfate, ferrous ammonium phosphate, sulfur, and/or an aluminum-iron complex; and drying the coated fertilizer granules forming dried and coated granules. ### Claim 2 (depends on 1) The method of claim 1, wherein the acid comprises sulfuric acid, phosphoric acid, nitric acid, and/or hydrochloric acid. ### Claim 3 (depends on 1) The method of claim 1, wherein the acidic pH is less than about 6.8. ### Claim 4 (depends on 1) The method of claim 1, wherein the acidic pH is less than about 6.0. ### Claim 5 (depends on 1) The method of claim 1, wherein the inorganic compound comprises an alkaline metal, ammonium thiosulfate, potassium thiosulfate, and/or sodium thiosulfate. ### Claim 6 (depends on 1) The method of claim 1, wherein the inorganic compound contains a cationic component and the fertilizer granules contain an anionic component. ### Claim 7 (depends on 6) The method of claim 6, wherein the anionic component comprises chloride ions (Cl−), nitrate ions (NO3−), ammonium nitrate ions (NH4NO3−), hydroxide ions (OH)−), and/or acetate ions (CH3COO−). ### Claim 8 (depends on 6) The method of claim 6, wherein the cationic component comprises barium ions, calcium ions, magnesium ions, aluminum ions, polyaluminum ions, iron ions, and/or sulfur ions. ### Claim 9 (depends on 6) The method of claim 6, wherein the cationic component comprises calcium ions and the anionic component comprises chloride ions. ### Claim 10 (depends on 1) The method of claim 1, wherein contacting comprises spraying an aqueous solution of the inorganic compound on surfaces of the fertilizer granules. ### Claim 11 (depends on 1) The method of claim 1, wherein the coating comprises from about 4 to about 40 pounds per ton of dried granules. ### Claim 12 (depends on 1) The method of claim 1, wherein the coating comprises from about 10 to about 20 pounds per ton of dried granules. ### Claim 13 (depends on 1) The method of claim 1, wherein the dried and coated granules comprise about 92% to about 100% solids. ### Claim 14 (depends on 1) The method of claim 1, wherein the dried and coated granules comprise about 96% to about 99% solids. ### Claim 15 (depends on 1) The method of claim 1, wherein the dried and coated granules comprise about 98% to about 99% solids. ### Claim 16 (depends on 1) The method of claim 1, wherein the dried and coated granules have reduced dust formation as compared to fertilizer granules that have not been so processed. ### Claim 17 (depends on 1) The method of claim 1, wherein the dried and coated granules are less absorbent to humidity as compared to fertilizer granules that have not been so processed. ### Claim 18 (depends on 1) The method of claim 1, wherein the dried and coated granules are resistant to self-heating as compared to fertilizer granules that have not been so processed. ### Claim 19 (depends on 1) The method of claim 1, wherein the dried and coated granules have a reduced odor as compared to fertilizer granules that have not been so processed. ### Claim 20 (depends on 1) The method of claim 1, wherein the dried and coated granules have a slow-release nutrient profile. ### Claim 21 (depends on 20) The method of claim 20, wherein the slow-release nutrient profile comprises a reduced rate, reduced amount, and/or differential release of one or more nutrients from the dried and coated granules. ### Claim 22 (depends on 1) The method of claim 1, wherein the dried and coated granules have an enhanced release of one or more nutrients. ### Claim 23 (depends on 22) The method of claim 22, wherein the one or more nutrients comprise nitrogen, phosphorus, potassium, sulfur, iron, organics, or a combination thereof. ### Claim 24 (depends on 1) The method of claim 1, further comprising adding micronutrients to the fertilizer granules. ### Claim 25 (depends on 24) The method of claim 24, wherein the micronutrients comprise boron, calcium, copper, magnesium, manganese, molybdenum, sulfur, zinc and/or combinations thereof. ### Claim 26 (depends on 1) The method of claim 1, wherein the fertilizer granules contain organic materials that are chemically bound to inorganic nutrients by covalent bonds, noncovalent bonds, electrostatic bonds, hydrogen bonds and/or combinations thereof. ### Claim 27 (depends on 1) The method of claim 1, wherein the contacting further comprises a surfactant. ### Claim 28 (depends on 27) The method of claim 27, wherein the surfactant comprises dodecylbenzyl sulfonic acid (DBSA), an ethoxylated alcohol of C10-C16, sodum lauryl ether sulfate, amine oxide, methyl salicylate, coco betaine, an anionic, cationic, or nonionic surfactants, or mixtures thereof. ### Claim 29 (depends on 1) Dried and coated granules made by the method of claim 1. ### Claim 30 A method of coating fertilizer containing organic material comprising: providing fertilizer comprised of organic materials that contain exposed chloride ions (Cl−), nitrate ions (NO3−), ammonium nitrate ions (NH4NO3−), hydroxide ions (OH)−), and/or acetate ions (CH3COO−); providing an inorganic compound that contains ions selected from the group consisting of Ca, Mg, Mn, Fe, Al, and Zn; contacting the fertilizer at an acidic pH with the inorganic compound forming a coating on the fertilizer, wherein the coating comprises aluminum, iron, aluminum-calcium sulfate, ferrous ammonium phosphate, sulfur, and/or an aluminum-iron complex; and drying the coated fertilizer. ### Claim 31 (depends on 30) The method of claim 30, wherein the coating comprises (Al)Cl3, (Al)chlorohydrate, polyaluminum chloride, (Ca)NH4NO3, (Ca)Cl2, (Fe)Cl3, FeSO4-7H2O, (Fe)3(SO4)2, (Mg)SO4, (Mg)Cl2, (Mn)Cl2, (Mn)NH4PO4, (Ca)3(PO4)2, monocal (Ca)(H2PO4)2H2O, and/or dical (Ca2)(H2PO4)4, and/or elemental sulfur. ### Claim 32 (depends on 30) The method of claim 30, wherein the acidic pH is less than about 6.8. ### Claim 33 (depends on 30) The method of claim 30, wherein the coated fertilizer, as compared to fertilizer not so processed: has reduced dust formation; is less absorbent to humidity; is resistant to self-heating; and/or has a reduced odor. ### Claim 34 (depends on 30) The method of claim 30, wherein the contacting further comprises a surfactant. ### Claim 35 (depends on 34) The method of claim 34, wherein the surfactant comprises dodecylbenzyl sulfonic acid (DBSA), an ethoxylated alcohol of C10-C16, sodium lauryl ether sulfate, amine oxide, coco betaine, an anionic, cationic, or nonionic surfactants, or mixtures thereof. ### Claim 36 A method of coating fertilizer granules comprising: providing fertilizer granules containing organic material and an acid; contacting the fertilizer granules at an acidic pH with an inorganic compound and a surfactant, wherein the inorganic compound chemically reacts with the acid of the fertilizer granules forming a coating on the fertilizer granules, wherein the coating comprises aluminum, iron, aluminum-calcium sulfate, calcium sulfate, ferrous ammonium phosphate, sulfur, and/or an aluminum-iron complex; and drying the coated fertilizer granules forming dried and coated granules. ### Claim 37 (depends on 36) The method of claim 36, wherein the acid comprises sulfuric acid, phosphoric acid, nitric acid, and/or hydrochloric acid. ### Claim 38 (depends on 36) The method of claim 36, wherein the acidic pH is less than about 6.8. ### Claim 39 (depends on 36) The method of claim 36, wherein the acidic pH is less than about 6.0. ### Claim 40 (depends on 36) The method of claim 36, wherein the inorganic compound contains a cationic component and the fertilizer granules contain an anionic component. ### Claim 41 (depends on 40) The method of claim 40, wherein the anionic component comprises chloride ions (Cl−), nitrate ions (NO3−), ammonium nitrate ions (NH4NO3−), hydroxide ions (OH)−), and/or acetate ions (CH3COO−). ### Claim 42 (depends on 40) The method of claim 40, wherein the cationic component comprises calcium ions and the anionic component comprises chloride ions. ### Claim 43 (depends on 36) The method of claim 36, wherein contacting comprises spraying an aqueous solution of the inorganic compound on surfaces of the fertilizer granules. ### Claim 44 (depends on 36) The method of claim 36, wherein the coating comprises from about 4 to about 40 pounds per ton of dried granules. ### Claim 45 (depends on 36) The method of claim 36, wherein the coating comprises from about 10 to about 20 pounds per ton of dried granules. ### Claim 46 (depends on 36) The method of claim 36, wherein the dried and coated granules comprise about 92% to about 100% solids. ### Claim 47 (depends on 36) The method of claim 36, wherein the dried and coated granules comprise about 96% to about 99% solids. ### Claim 48 (depends on 36) The method of claim 36, wherein the dried and coated granules comprise about 98% to about 99% solids. ### Claim 49 (depends on 36) The method of claim 36, wherein the dried and coated granules have reduced dust formation as compared to fertilizer granules that have not been so processed. ### Claim 50 (depends on 36) The method of claim 36, wherein the dried and coated granules are less absorbent to humidity as compared to fertilizer granules that have not been so processed. ### Claim 51 (depends on 36) The method of claim 36, wherein the dried and coated granules are resistant to self-heating as compared to fertilizer granules that have not been so processed. ### Claim 52 (depends on 36) The method of claim 36, wherein the dried and coated granules have a reduced odor as compared to fertilizer granules that have not been so processed. ### Claim 53 (depends on 36) The method of claim 36, wherein the dried and coated granules have a slow-release nutrient profile. ### Claim 54 (depends on 53) The method of claim 53, wherein the slow-release nutrient profile comprises a reduced rate, reduced amount, and/or differential release of one or more nutrients from the dried and coated granules. ### Claim 55 (depends on 36) The method of claim 36, wherein the dried and coated granules have an enhanced release of one or more nutrients. ### Claim 56 (depends on 55) The method of claim 55, wherein the one or more nutrients comprise nitrogen, phosphorus, potassium, sulfur, iron, organics, or a combination thereof. ### Claim 57 (depends on 36) The method of claim 36, further comprising adding micronutrients to the fertilizer granules. ### Claim 58 (depends on 57) The method of claim 57, wherein the micronutrients comprise boron, calcium, copper, magnesium, manganese, molybdenum, sulfur, zinc and/or combinations thereof. ### Claim 59 (depends on 36) The method of claim 36, wherein the fertilizer granules contain organic materials that are chemically bound to inorganic nutrients by covalent bonds, noncovalent bonds, electrostatic bonds, hydrogen bonds and/or combinations thereof. ### Claim 60 (depends on 36) The method of claim 36, wherein the surfactant comprises dodecylbenzyl sulfonic acid (DBSA), an ethoxylated alcohol of C10-C16, sodium lauryl ether sulfate, amine oxide, coco betaine, an anionic, cationic, or nonionic surfactants, or mixtures thereof. ### Claim 61 A method of coating fertilizer containing organic material comprising: providing fertilizer comprised of organic materials that contain exposed chloride ions (Cl−), nitrate ions (NO3−), ammonium nitrate ions (NH4NO3−), hydroxide ions (OH)−), and/or acetate ions (CH3COO−); providing an inorganic compound that contains ions selected from the group consisting of Ca, Mg, Mn, Fe, Al, and Zn; contacting the fertilizer at an acidic pH with the inorganic compound and a surfactant forming a coating on the fertilizer, wherein the coating comprises aluminum, iron, aluminum-calcium sulfate, calcium sulfate, ferrous ammonium phosphate, sulfur, and/or an aluminum-iron complex; and drying the coated fertilizer. ### Claim 62 (depends on 61) The method of claim 61, wherein the acidic pH is less than about 6.8. ### Claim 63 (depends on 61) The method of claim 61, wherein the coated fertilizer, as compared to fertilizer not so processed: has reduced dust formation; is less absorbent to humidity; is resistant to self-heating; and/or has a reduced odor. ### Claim 64 (depends on 61) The method of claim 61, wherein the surfactant comprises dodecylbenzyl sulfonic acid (DBSA), an ethoxylated alcohol of C10-C16, sodium lauryl ether sulfate, amine oxide, methyl salicylate, coco betaine, an anionic, cationic, or nonionic surfactants, or mixtures thereof.