Potassium sulfate - urea ammonium sulfate fertilizers and methods for producing and using the same

Abstract

A potassium sulfate-urea ammonium sulfate (KS-UAS) composition and methods for making and using the same are disclosed. The composition can include urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate. The composition can include 12 wt.% or less chloride based on the weight of the composition.

Description

DESCRIPTIONPOTASSIUM SULFATE - UREA AMMONIUM SULFATE FERTILIZERS AND METHODS FOR PRODUCING AND USING THE SAME CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of Indian Patent Application No.202441086638, filed November 11, 2024, the contents of which is incorporated into the present application by reference in its entirety.BACKGROUND OF THE INVENTIONA. Field of the Invention

[0002] The invention generally concerns a potassium sulfate - urea ammonium sulfate composition that includes urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate. The composition may include 12 wt.% chloride or less. B. Description of Related Art

[0003] Soil nutrients, such as nitrogen, phosphorus, potassium, and sulfur, as well as trace elements such as iron, zinc, copper, and magnesium, are useful for achieving thriving agriculture and growth of plants. Upon repeated planting cycles, the quantity of these nutrients in the soil may be depleted, resulting in inhibited plant growth and decreased production. To counter this effect, fertilizers have been developed to help replace the depleted vital nutrients. Single-nutrient fertilizers and multi-nutrient fertilizers, such as fertilizer blends, have been developed to meet the varied needs of crop production worldwide.

[0004] One of the many fertilizers that are used is potassium sulfate. However, the production of potassium sulfate can in some instances produce a large amount of chloride content. Chloride ions and some chlorinated compounds can be toxic to certain crops. Chlorinated compounds and ions can be produced by reacting a potassium compound, such as potassium chloride, with a sulfate compound, such as ammonium sulfate, to produce potassium sulfate and ammonium chloride.

[0005] Production and use of potassium sulfate can provides other benefits. Over the past decade, the world has become more conscious of the adverse effects on the environmentposed by disposing processing industries, such as waste calcium sulfate gypsums like phosphogypsum (PG) or red gypsum (RG). Waste gypsums have been disposed by stacking on land or discharge to the sea. However, both methods of disposal have possible adverse environmental effects. Further, reduction of CO2 emission is presently among the top priorities of many industries. Chemical utilization of CO2 through its reduction to CO and involvement of chemical reactions requires excessive consumption of energy. That is one of the reasons why, presently, many chemical companies have made significant efforts to reduce CO2 emission by storing CO2 in underground deep storage. Others have looked to reduce CO2 by reacting CO2 with other ingredients to produce useful products. Such products include ammonium sulfate by reacting CO2, that would have been stored or released, with calcium sulfate and a source of ammonia to form the ammonium sulfate. The ammonium sulfate can be used directly or can be reacted with other ingredients, such as potassium chloride to form potassium sulfate, which can be used as a fertilizer.SUMMARY OF THE INVENTION

[0006] A discovery has been made that addresses at least some of the problems associated with potassium sulfate based fertilizers. The discovery is premised on producing a composition containing a urea ammonium sulfate (UAS) adduct (2(NH4)2SO4 / CO(NH2)2) potassium sulfate, ammonium chloride, and ammonium sulfate, combined referred to here as potassium sulfate - urea ammonium sulfate (KS-UAS), that consumes waste gypsum (calcium sulfate dihydrate) and CO2 during the production process. This invention describes a KS-UAS composition formulation of low chloride content, the production of the composition, and the use of the composition. The KS-UAS is produced from reacting excess ammonium sulfate with desirable quantities of potassium chloride and urea. The reduction of chloride content in the final product of the process was achieved by use of high ratio of ammonium sulfate to potassium chloride. The mechanical strength and slow release performance of the resulting material may also be improved by addition of a binder, such as bentonite clay.

[0007] The method for producing the composition comprises integration of ammonium sulfate produced by a process for CO2 de-carbonization via consumption of calcium sulfate (gypsum) waste. This process is beneficial by a) utilization of calcium sulfate gypsum waste and CO2 de-carbonization, b) production of low chloride content potassium sulfate without having to remove the chloride, c) application of target ratios of ammonium sulfate / potassiumchloride / urea which allows production of various formulations with acceptable chloride levels, and d) even distribution of ammonium sulfate in the composition. This ratio balancing and selection strategy involving ammonium sulfate, potassium chloride, and urea allows reduction of Cl content from a standard 25.2% to 6.3% or lower, or any concentration between or ratio thereof. The final product produced can be used as a high nitrogen content fertilizer. For example, fertilizers of the present invention can include 18 wt.% to 20 wt.% N, 6 wt.% to 13 wt.% K, 15 wt.% to 20 wt.% S, and 6 wt.% to 12 wt.% Cl based on the weight of the fertilizer. In some preferred instances, the composition can contain less than 12, 10, 8, 6, 4, or 2 wt.% Cl based on the weight of the composition. The fertilizer compositions can be beneficial where higher concentrations of nitrogen are desired.

[0008] In one aspect of the invention, a method of making a potassium sulfate-urea ammonium sulfate composition is described. The method may include reacting potassium chloride and urea with ammonium sulfate in excess to the molar equivalent of ammonium sulfate needed to produce potassium sulfate. The method may produce a composition comprising a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate, wherein the composition formed comprises no more than 12 wt. % chloride by weight of the composition. In some instances, the excess molar equivalents of ammonium sulfate may include at least two equivalents of ammonium sulfate. In some instances, the composition may include 18 wt.% to 20 wt.% N, such as 18 wt.% N, 19 wt.% N, or 20 wt.% N. In some instances, the composition may include 6 wt.% to 13 wt.% K, such as 6 wt.% K, 7 wt.% K, 8 wt.% K, 9 wt.% K, 10 wt.% K, 11 wt.% K, 12 wt.% K, or 13 wt.% K. In some instances, the composition may include 15 wt.% to 20 wt.% S, such as 15 wt.% S, 16 wt.% S, 17 wt.% S, 18 wt.% S, 19 wt.% S, or 20 wt.% S. In some instances, the composition may include 6 wt.% to 12 wt.% Cl, such as 6 wt.% Cl, 7 wt.% Cl, 8 wt.% Cl, 9 wt.% Cl, 10 wt.% Cl, 11 wt.% Cl, or 12 wt.% Cl.

[0009] In some instances, the method may further include adding bentonite in the reaction. In some instances, the method may further include adding bentonite in the composition. In some instances, at least a portion of the urea-ammonium sulfate adduct, the potassium sulfate, the ammonium chloride, and / or the ammonium sulfate may be encapsulated by the bentonite.

[0010] In some instances, the method may further includes reacting calcium sulfate, CO₂, and a source of ammonia to produce the ammonium sulfate and produce calcium carbonate. In some instances, the source of ammonia may include ammonia gas and / or ammoniumhydroxide. In some instances, at least some amount of calcium carbonate may be separated from the ammonium sulfate prior to reacting the ammonium sulfate with the potassium chloride and the urea.

[0011] In some instances, the ammonium sulfate may be produced by utilization of gypsum waste and / or CO₂ from a decarbonization source. In some instances, the waste gypsum may be red gypsum, phosphogypsum, and / or flue gas gypsum. In some instances, the method may further include granulation and / or drying the composition.

[0012] In some instances, the potassium chloride may be reacted with the urea and the excess ammonium sulfate at a temperature of 65 °C to 95 °C. The reaction can be performed at a temperature of greater than 60 °C. In some instances, the temperature is at or greater than 65 °C, 70 °C, 75 °C, or 80 °C, or any temperature there between. In some instances, the temperature is 65 °C to 95 °C, 70 °C to 95 °C, 70 °C to 90 °C, 65 °C to 90 °C, or 75 °C to 85 °C, or any combination of these ranges or ranges there between. In some instances, the potassium chloride may be reacted with the urea and the excess ammonium sulfate at a pressure of 1 bar to 10 bar. In some instances, the pressure is at or greater than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 bar any pressure there between.

[0013] In another aspect of the invention a composition is described. The composition may include a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, ammonium sulfate, and / or bentonite. In some instances, the urea-ammonium sulfate adduct, the potassium sulfate, the ammonium chloride, and / or the ammonium sulfate may be encapsulated by the bentonite.

[0014] In the context of the present invention, at least the following 15 aspects are disclosed.

[0015] Aspect 1 is directed to a method of making a potassium sulfate - urea ammonium sulfate fertilizer (KS-UAS), the method comprising reacting potassium chloride and urea with an excess molar equivalent of ammonium sulfate to produce a product comprising a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate, wherein the KS-UAS formed comprises no more than 12 wt. % chloride.

[0016] Aspect 2 is directed to the method of aspect 1, wherein the excess molar equivalents of ammonium sulfate comprises at least two equivalents of ammonium sulfate.

[0017] Aspect 3 is directed to the method of any one of aspects 1 to 2, wherein the KS-UAS comprises 18 wt.% to 20 wt.% N, 6 wt.% to 13 wt.% K, 15 wt.% to 20 wt.% S, and 6 wt.% to 12 wt.% Cl.

[0018] Aspect 4 is directed to the method of any one of aspects 1 to 3, wherein the method further comprises adding bentonite in the reaction and / or in the product.

[0019] Aspect 5 is directed to the method of aspect 4, wherein at least a portion of the urea-ammonium sulfate adduct, the potassium sulfate, the ammonium chloride, and / or the ammonium sulfate is encapsulated by the bentonite.

[0020] Aspect 6 is directed to the method of any one of aspects 1 to 5, wherein the method further comprises reacting calcium sulfate, CO₂, and a source of ammonia to produce the ammonium sulfate and produce calcium carbonate.

[0021] Aspect 7 is directed to the method of aspect 6, wherein the source of ammonia comprises ammonia gas and / or ammonium hydroxide.

[0022] Aspect 8 is directed to the method of any one aspects 6 to 7, wherein at least some amount of calcium carbonate is separated from the ammonium sulfate prior to reacting the ammonium sulfate with the potassium chloride and the urea.

[0023] Aspect 9 is directed to the method of any one of aspects 6 or 8, wherein the ammonium sulfate is produced by utilization of gypsum waste and / or CO₂ from a decarbonization source.

[0024] Aspect 10 is directed to the method of aspect 9, wherein the waste gypsum is red gypsum, phosphogypsum, and / or flue gas gypsum.

[0025] Aspect 11 is directed to the method of any one of aspects 1 to 10, further comprising granulation and / or drying the KS-UAS.

[0026] Aspect 12 is directed to the method of any one of aspects 1 to 11, wherein the potassium chloride is reacted with the urea and the excess ammonium sulfate at a temperature of 65 °C to 95 °C.

[0027] Aspect 13 is directed to the method of any one of aspects 1 to 12, wherein the potassium chloride is reacted with the urea and the excess ammonium sulfate at a pressure of 1 bar to 10 bar.

[0028] Aspect 14 is directed to a composition comprising a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, ammonium sulfate, and bentonite.

[0029] Aspect 15 is directed to the composition of aspect 14, wherein the urea-ammonium sulfate adduct, the potassium sulfate, the ammonium chloride, and / or the ammonium sulfate is encapsulated by the bentonite.

[0030] The following includes definitions of various terms and phrases used throughout this specification.

[0031] The term “fertilizer” is defined as a material applied to soils or to plant tissues to supply one or more plant nutrients essential or beneficial to the growth of plants and / or stimulants or enhancers to increase or enhance plant growth. Non-limiting examples of fertilizers include materials having one or more of urea, ammonium nitrate, calcium ammonium nitrate, one or more superphosphates, binary NP fertilizers, binary NK fertilizers, binary PK fertilizers, NPK fertilizers, molybdenum, zinc, copper, boron, cobalt, and / or iron. In some aspects, fertilizers include agents that enhance plant growth and / or enhance the ability for a plant to receive the benefit of a fertilizer, such as, but not limited to bio stimulants, urease inhibitors, and nitrification inhibitors. In some particular instances, the fertilizer is urea.

[0032] The term “micronutrient” is defined as a chemical element or substance required in trace amounts for the normal growth and development of a plant. Non-limiting examples of micronutrients include B, Cu, Fe, Mn, Mo, Zn, Se, and Si or compounds thereof.

[0033] The term “secondary nutrient” is defined as a chemical element or substance required in moderate amounts for plant growth and are less likely to limit crop growth in comparison to N, P, and K. Non-limiting examples of secondary nutrients include Ca, Mg, and S.

[0034] The term “organic agent” is defined as a substance that is produced by or part of an organism. Non-limiting examples of organic agents suitable for a fertilizer include neem oil,seaweed extract, bio- stimulants, char, ashes from incineration of animal waste or animal tissues, and diatomaceous earth.

[0035] The term “granule” can include a solid material. A granule can have a variety of different shapes, non-limiting examples of which include a spherical, a puck, an oval, a rod, an oblong, or a random shape.

[0036] The terms “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment, the terms are defined to be within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0037] The terms “wt.%”, “vol.%”, or “mol.%” refers to a weight percentage of a component, a volume percentage of a component, or molar percentage of a component, respectively, based on the total weight, the total volume of material, or total moles, that includes the component. In a non-limiting example, 10 grams of component in 100 grams of the material is 10 wt.% of component.

[0038] The term “substantially” and its variations are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.

[0039] The terms “inhibiting” or “reducing” or “preventing” or “avoiding” or any variation of these terms, when used in the claims and / or the specification includes any measurable decrease or complete inhibition to achieve a desired result.

[0040] The term “effective,” as that term is used in the specification and / or claims, means adequate to accomplish a desired, expected, or intended result.

[0041] The use of the words “a” or “an” when used in conjunction with any of the terms “comprising,” “including,” “containing,” or “having” in the claims, or the specification, may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”

[0042] The words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”), or “containing” (and any form ofcontaining, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Advantages of the present invention may become apparent to those skilled in the art with the benefit of the following detailed description and upon reference to the accompanying drawings.

[0044] FIGURE a schematic of a system that can be used to produce KS-UAS fertilizer granules of the present invention.

[0045] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings. The drawings may not be to scale.DETAILED DESCRIPTION OF THE INVENTION

[0046] A composition containing a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate is disclosed herein. This invention describes the production of the composition with low chloride content, such as at or below 12 wt. % by weight of the composition. The complex potassium sulfate / urea-Ammonium sulfate (UAS) / ammonium chloride is produced from reacting excess ammonium sulfate with desirable quantities of potassium chloride and urea. The composition produced had a reduce chloride content and was produced with a high ratio of ammonium sulfate to potassium chloride and urea. The mechanical strength and slow release performance of the resulting material was improved by addition of a binder, such as bentonite clay. This method may also include production of ammonium sulfate in a process for CO2 de-carbonization via consumption of calcium sulfate (gypsum) waste. The final composition produced can be used as a high nitrogen content fertilizer. For example, granules of the present invention can include 18 wt.% to 20 wt.% N, 6 wt.% to 13 wt.% K, 15 wt.% to 20 wt.% S, and 6 wt.% to 12 wt.% Cl. In some preferred instances, the composition can contain less than 10 wt.% Cl based on the weight of the composition. Use of the composition as a fertilizer can be beneficial where higher concentrations of nitrogen are desired.

[0047] These and other non-limiting aspects of the present invention are discussed in further detail in the following sections.A. Process to Produce a KS-UAS Composition

[0048] A composition containing a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate can be produced by the following non-limiting reactions. The reaction of gypsum with the CO2 + a source of ammonia, such as the nonlimiting example reaction (1). The reaction of a potassium source + ammonium sulfate, such as the non-limiting example reaction (2). In some instances, calcium carbonate (CaCO3) in the reaction (1) is separated from the ammonium sulfate ((NH4)2SO4) of reaction (1) prior to react with the potassium source, such as KCl. The reaction of ammonium sulfate + urea, such as the non-limiting example reaction (3). In some instances, calcium carbonate (CaCO3) in the reaction (1) is separated from the ammonium sulfate ((NH4)2SO4) of reaction (1) prior to react with the urea. In some instances, potassium chloride and urea is reacted with an excess molar equivalent of ammonium sulfate to produce a composition comprising a ureaammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate. The reaction equation (4) below is not a balanced equation, but represents some of the reactants and products by integrating all the chemical reactions (1-3) below:CaSO4.2H2O + CO2+ 2NH3→ CaCO3+ (NH4)2SO4+ H2O (1)2KCl + (NH4)2SO4→ K2SO4+ 2NH4Cl (2)2(NH4)2SO4+ CO(NH2)2→2(NH4)2SO4 / CO(NH2)2(UAS) (3)2KCl + 2(NH4)2SO4+ CO(NH2)2→K2SO4 / 2NH4Cl / 2(NH4)2SO4 / CO(NH2)2(UAS) (4)

[0049] In some instances, urea and potassium chloride may be added to the (NH4)2SO4solution, gel, and / or solid in different forms. In some instances, urea and potassium chloride can be added to a gel of (NH4)2SO4in the form of melt urea to reduce the cost of solvent evaporation.

[0050] In some instances, the composition produced may contain no more than 12 wt. % chloride. Table 1 describes different compositions and change of nitrogen, potassium, sulfur, and chloride concentrations in the formulations. When ammonium sulfate was used in an amount twice more than required for a stoichiometric reaction of reaction 2 and urea is used in an amount of urea / ammonium sulfate at a mole ratio of 1:1, chloride content is reduced to 11.74% wt. of the composition compared to 25.3 wt.% if no excess ammonium sulfate is used and no urea is added. When ammonium sulfate was used in an amount four times more than required for a stoichiometric reaction and urea is used in an amount of urea / ammonium sulfate at a mole ratio of 1:1 the chloride content in the final composition is reduced to8.17 % wt. When ammonium sulfate was used in an amount six times more than required for a stoichiometric reaction and urea is used in an amount of urea / ammonium sulfate at a mole ratio of 1: 1, the chloride content in the final composition is reduced to 6.27%.Table 1

[0051] In other embodiment of the invention, the sulfur content in the composition can be reduced by using different ratios of ammonium sulfate to urea. The ratio of ammonium sulfate to urea can be varied within 0.5 to 6. The composition with high content of urea allows to keep nitrogen content high and also provides more oxygen to the plant which is needed for formation of carbohydrates. Further, the minerals content in the final formulation will be slightly decrease with addition of a binder such as bentonite clay.

[0052] The free-moisture content of the composition can be less than 1 wt.%, preferably less than 0.8 wt.%, less than 0.5 wt.% water or 0.25 wt.% to 0.7 wt.% water. In some instances, the free moisture content is 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, or 0 wt.%.

[0053] The composition can be comprised in a granule. In some instances, the granule comprises one or more particles. In some instances, the granule has a core-shell form. In certain non-limiting aspects, the particles can have an average particle size of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, or 4400 micrometers or any size there between or range thereof. In some embodiments, the particles can be elongated particles or can be substantially spherical particles or other shapes, or combinations of such shapes. Nonlimiting examples of shapes include a sphere, a puck, an oval, a rod, an oblong, or a random shape.

[0054] The granules can have a crush strength of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 kg / granule, or more, or any amount there between, preferably 2 kg / granule to 5 kg / granule.

[0055] The reactions (1), (2), (3) and / or (4) can occur at ambient temperature or any temperature at, between, above, below, or range 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100°C. In some instances reaction (1), (2), (3), and / or reaction (4) occurs at approximately 50°C to 100°C. In some instances reaction (1), (2), (3), and / or reaction (4) occurs at a pressure of 1 bar to 10 bar. In some instances, the pressure is at or greater than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 bar any pressure there between. The reactions (1), (2), (3), and / or reaction (4) can be reacted in a continuous reaction or as a batch. The reactions (1), (2), (3), and / or reaction (4) can be reacted for at, between, above, below, or range of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 minutes, and / or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 hours, and / or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 days. The feeds, reactants, products, etc. can be transported or moved into, out of, and / or through the system at a rate of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990, or 1000 g / minute, kg / minute, tons / minute. The feeds, reactants, products, etc. can be provided, obtained, and / or transported at a pressure of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, and / or 50 bar.

[0056] The source of ammonia, can in some instances be one or more of a solution of ammonium hydroxide, ammonium, ammonium carbonate, ammonia gas, succinimide, and / or phthalimide. The source of nitrogen, can in some instances be ammonium sulfate, ammonium chloride, a urea adduct, urea solution, molten urea, granular urea, and / or prilled urea. The products of the reaction of calcium sulfate (CaSO₄), carbon dioxide (CO₂), a source of ammonia, a source of nitrogen, and a source of potassium can in some instances also producewater, calcium sulfate (CaSO₄), ammonia (NH₃), ammonium hydroxide (NH₄OH), potassium hydroxide (KOH), urea (CO(NH₂)₂), ammonium sulfate ((NH₄)₂SO₄), ammonium chloride (NH₄Cl), and / or calcium carbonate (CaCO₃).

[0057] Referring to the Figure, the disclosed embodiment scheme demonstrates simultaneous utilization of CO₂ and CaSO₄, and a source of ammonia to produce ammonium sulfate and / or CaCO₃, and reacting the produced ammonium sulfate with the potassium chloride and the urea for producing useful products such as potassium sulfate-urea ammonium sulfate (K₂SO₄ / 2NH₄Cl / 2(NH₄)₂SO₄ / CO(NH₂)₂) fertilizer. In some instances, calcium carbonate can be removed during the process, and can be used as a starting material for other products, including a fertilizer, and / or blended with other compositions, including those to generate a fertilizer. The system 100 can include a first reactor 102 and a second reactor 104. The feed mixture ingredients 106, which can include calcium sulfate (CaSO₄), carbon dioxide (CO₂), and a source of ammonia, can be added in combination or separately to the first reactor 102. All or a portion of feed mixture 106 can be reacted in the first reactor 102 to generate a reaction product, which can comprise ammonium sulfate (NH₄)₂SO₄, and calcium carbonate (CaCO₃),. The calcium carbonate 112 can be separated in some instances from the ammonium sulfate. In some instances the separation occurs in a separator (not shown). Mixture 108 can comprise the ammonium sulfate (NH₄)₂SO₄ that has optionally at least partially been purified by removal of at least some of the calcium carbonate. Mixture 108 can be delivered to the second reactor 104. In some instances, potassium chloride (KCl) 114 and urea 116 may be added to the excess molar equivalents of ammonium sulfate. All or a portion of 114 and 116 can be reacted with ammonium sulfate in the second reactor 104 to generate a fertilizer product 110, which can comprise a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate. In some instances, the system is capable of further adding bentonite in the reaction of the second reactor 104 (not shown) and / or in the product. In some instances, the calcium carbonate is separated from the ammonium sulfate. In some instances, the calcium carbonate and ammonium sulfate, are not separated. In some instances the separation occurs in a separator. In some instances, all or a portion of the urea 116 can be combined with the mixture 108 (not shown). In some instances, all or a portion of the mixture 108 can be combined with urea to form a urea ammonium sulfate adduct. All or a portion of the fertilizer product 110 can be removed from the system into a separate granulation and / or drying units (not shown). All or a portion of the calcium carbonate 112 can be removed from the system. In some instances, the fertilizer 110can further comprise water, calcium sulfate (CaSO₄), ammonia (NH₃), ammonium hydroxide (NH₄OH), potassium chloride (KCl), urea (CO(NH₂)₂), ammonium chloride (NH₄Cl), and / or calcium carbonate (CaCO₃).

[0058] The granules of the present invention can be made using a granulation system (not shown). The granulation system can be a continuous processes or batch processes capable of handling slurries. In some instances, drying the granule can enable agglomeration to form solid granules and can also create crystal bridges to enable crystallization of the UAS adduct. In some embodiments, the granules are dried or further dried in a dryer or drying zoneB. Compositions

[0059] A composition may include urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate, and optionally bentonite. In some instances, the urea-ammonium sulfate adduct, the potassium sulfate, the ammonium chloride, and / or the ammonium sulfate is encapsulated by the bentonite.

[0060] The composition can be used alone or in combination with other fertilizer actives and micronutrients. The other fertilizer actives and micronutrients can be added with any of the ingredients at the beginning of the production process, a granulation process, etc. or at any later stage.

[0061] Non-limiting examples of additional additives can be micronutrients, primary nutrients, and secondary nutrients. A micronutrient is a botanically acceptable form of an inorganic or organometallic compound such as boron, copper, iron, chloride, manganese, molybdenum, nickel, or zinc. A primary nutrient is a material that can deliver nitrogen, phosphorous, and / or potassium to a plant. Nitrogen-containing primary nutrients may include urea, ammonium nitrate, ammonium sulfate, diammonium phosphate, monoammonium phosphate, urea-formaldehyde, a urea adduct, or combinations thereof. A secondary nutrient is a substance that can deliver calcium, magnesium, and / or sulfur to a plant. Secondary nutrients may include lime, gypsum, superphosphate, or a combination thereof. For example, in some instances the composition can contain a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, ammonium sulfate, or bentonite, or a combination thereof.

[0062] In one aspect, the composition may be in the form of a granule. The granule may be included in a blended or compounded fertilizer composition comprising other fertilizers, such as other fertilizer granules. Additional fertilizers can be chosen based on the particular needs of certain types of soil, climate, or other growing conditions to maximize the efficacy of the granules in enhancing plant growth and crop yield. The other fertilizer granules can be granules of single super phosphate (SSP), triple super phosphate (TSP), monoammonium phosphate (MAP), diammonium phosphate (DAP), muriate of potash (MOP), and / or sulfate of potash (SOP), and the like.

[0063] In one aspect, the a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate, and optionally bentonite compositions can comprise one or more inhibitors. The inhibitor can be a urease inhibitor or a nitrification inhibitor, or a combination thereof. In one aspect, the composition can comprise a urease inhibitor and a nitrification inhibitor. In one aspect, the inhibitor can be a urease inhibitor. Suitable urease inhibitors include, but are not limited to, N-(n-butyl) thiophosphoric triamide (NBTPT) and phenylphosphorodiamidate (PPDA). In one aspect, the composition can comprise NBTPT or PPDA, or a combination thereof. In another aspect, the inhibitor can be a nitrification inhibitor. Suitable nitrification inhibitors include, but are not limited to, 3,4-dimethylpyrazole phosphate (DMPP), dicyandiamide (DCD), thiourea (TU), 2-chloro-6-( trichloromethyl) -pyridine (Nitrapyrin), 5-ethoxy-3-trichloromethyl-l,2,4-thiadiazol, which is sold under the tradename Terrazole®, by OHP Inc., USA, 2-amino 4-chloro 6-methyl pyrimidine (AM), 2-mercaptobenzothiazole (MBT), or 2-sulfanilamidothiazole (ST), and any combination thereof. In one aspect, nitrification inhibitor can comprise DMPP, DCD, TU, nitrapyrin, 5-ethoxy-3-trichloromethyl-l,2,4-thiadiazol, AM, MBT or ST, or a combination thereof. In one aspect, the composition can comprise NBTPT, DMPP, TU, DCD, PPDA, nitrapyrin, 5-ethoxy-3-trichloromethyl-l,2,4-thiadiazol, AM, MBT, or ST or a combination thereof.C. Methods of Using the KS-UAS Composition

[0064] The composition of the present invention can be used in methods of increasing the amount of nitrogen in soil and of enhancing plant growth. Such methods can include applying to the soil an effective amount of the composition of the present invention. The method may include increasing the growth and yield of crops, trees, ornamentals, etc. such as, for example, palm, coconut, rice, wheat, corn, barley, oats, and soybeans. The methodcan include applying fertilizer granules of the present invention to at least one of a soil, an organism, a liquid carrier, a liquid solvent, etc.

[0065] Non-limiting examples of plants that can benefit from the fertilizer of the present invention include vines, trees, shrubs, stalked plants, fems, etc. The plants may include orchard crops, vines, ornamental plants, food crops, timber, and harvested plants. The plants may include Gymnosperms, Angiosperms, and / or Pteridophytes. The Gymnosperms may include plants from the Araucariaceae, Cupressaceae, Pinaceae, Podocarpaceae, Sciadopitaceae, Taxaceae, Cycadaceae, and Ginkgoaceae families. The Angiosperms may include plants from the Aceraceae, Agavaceae, Anacardiaceae, Annonaceae, Apocynaceae, Aquifoliaceae, Araliaceae, Arecaceae, Asphodelaceae, Asteraceae, Berberidaceae, Betulaceae, Bignoniaceae, Bombacaceae, Boraginaceae, Burseraceae, Buxaceae, Canellaceae, Cannabaceae, Capparidaceae, Caprifoliaceae, Caricaceae, Casuarinaceae, Celastraceae, Cercidiphyllaceae, Chrysobalanaceae, Clusiaceae, Combretaceae, Cornaceae, Cyrillaceae, Davidsoniaceae, Ebenaceae, Elaeagnaceae, Ericaceae, Euphorbiaceae, Fabaceae, Fagaceae, Grossulariaceae, Hamamelidaceae, Hippocastanaceae, Illiciaceae, Juglandaceae, Lauraceae, Lecythidaceae, Lythraceae, Magnoliaceae, Malpighiaceae, Malvaceae, Melastomataceae, Meliaceae, Moraceae, Moringaceae, Muntingiaceae, Myoporaceae, Myricaceae, Myrsinaceae, Myrtaceae, Nothofagaceae, Nyctaginaceae, Nyssaceae, Olacaceae, Oleaceae, Oxalidaceae, Pandanaceae, Papaveraceae, Phyllanthaceae, Pittosporaceae, Platanaceae, Poaceae, Polygonaceae, Proteaceae, Punicaceae, Rhamnaceae, Rhizophoraceae, Rosaceae, Rubiaceae, Rutaceae, Salicaceae, Sapindaceae, Sapotaceae, Simaroubaceae, Solanaceae, Staphyleaceae, Sterculiaceae, Strelitziaceae, Styracaceae, Surianaceae, Symplocaceae, Tamaricaceae, Theaceae, Theophrastaceae, Thymelaeaceae, Tiliaceae, Ulmaceae, Verbenaceae, and / or Vitaceae family.

[0066] The effectiveness of a fertilizer comprising the composition of the present invention can be ascertained by measuring the amount of nitrogen in the soil at various times after applying the fertilizer composition to the soil. It is understood that different soils have different characteristics, which can affect the stability of the nitrogen in the soil. The effectiveness of a fertilizer composition can also be directly compared to other fertilizer compositions by doing a side-by-side comparison in the same soil under the same conditions.EXAMPLES

[0067] The present invention will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes only, and are not intended to limit the invention in any manner. Those of skill in the art will readily recognize a variety of noncritical parameters which can be changed or modified to yield essentially the same results.Example 1(Processes to Prepare KS-UAS Fertilizer)

[0068] Processes for making a KS-UAS fertilizer granule of the present invention were performed or can be performed by using the system described in the FIGURE and in Section A of the Detailed Description of the Invention. It was found that when a stoichiometric excess of ammonium sulfate (e.g., 2 mole % to 6 mole % excess of ammonium sulfate for the molar amount of potassium sulfate produced) was used in the reaction, a composition containing no more than 12 wt. % chloride may be produced.

[0069] 38 g (NH₄)₂SO₄ produced from a reaction of calcium sulfate, CO₂, and a source of ammonia was dissolved in 100 ml of water. In a separate beaker, 14.9 potassium chloride was dissolved in 50 ml water and the produced solutions were mixed with 10 g urea and the 6 g bentonite clay. The mixture was continuously stirred at 40°C for 4 hours, then the temperature of the mixture was increased to 55 °C and the stirring was continued at this temperature until the mixture produced a gel phase product. The gel was then pushed through a funnel to produce granules with a size of 3-4 mm. The final product contained urea ammonium sulfate (NH₄)₂SO₄.CO(NH₂)₂, urea, excess of ammonium sulfate, potassium sulfate (K₂SO₄), and ammonium chloride (NH₄Cl), with a nutrient content of 18.4% nitrogen (N), 13.3% sulfur (S), 13.6% potassium (K2O) and 10.3 % chloride (Cl). The excess ammonium sulfate may form complex with the urea complex salt as urea ammonium sulfate.

Claims

CLAIMS1. A method of making a potassium sulfate - urea ammonium sulfate fertilizer (KS-UAS), the method comprising reacting potassium chloride and urea with an excess molar equivalent of ammonium sulfate to produce a product comprising a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, and ammonium sulfate, wherein the KS-UAS formed comprises no more than 12 wt. % chloride.

2. The method of claim 1, wherein the excess molar equivalents of ammonium sulfate comprises at least two equivalents of ammonium sulfate.3 The method of any one of claims 1 to 2, wherein the KS-UAS comprises 18 wt.% to 20 wt.% N, 6 wt.% to 13 wt.% K, 15 wt.% to 20 wt.% S, and 6 wt.% to 12 wt.% Cl.

4. The method of any one of claims 1 to 3, wherein the method further comprises adding bentonite in the reaction and / or in the product.

5. The method of claim 4, wherein at least a portion of the urea-ammonium sulfate adduct, the potassium sulfate, the ammonium chloride, and / or the ammonium sulfate is encapsulated by the bentonite.

6. The method of any one of claims 1 to 5, wherein the method further comprises reacting calcium sulfate, CO₂, and a source of ammonia to produce the ammonium sulfate and produce calcium carbonate.

7. The method of claim 6, wherein the source of ammonia comprises ammonia gas and / or ammonium hydroxide.

8. The method of any one claims 6 to 7, wherein at least some amount of calcium carbonate is separated from the ammonium sulfate prior to reacting the ammonium sulfate with the potassium chloride and the urea.

9. The method of any one of claims 6 or 8, wherein the ammonium sulfate is produced by utilization of gypsum waste and / or CO₂ from a decarbonization source.

10. The method of claim 9, wherein the waste gypsum is red gypsum, phosphogypsum, and / or flue gas gypsum.

11. The method of any one of claims 1 to 10, further comprising granulation and / or drying the KS-UAS.

12. The method of any one of claims 1 to 11, wherein the potassium chloride is reacted with the urea and the excess ammonium sulfate at a temperature of 65 °C to 95 °C.

13. The method of any one of claims 1 to 12, wherein the potassium chloride is reacted with the urea and the excess ammonium sulfate at a pressure of 1 bar to 10 bar.

14. A composition comprising a urea-ammonium sulfate adduct, potassium sulfate, ammonium chloride, ammonium sulfate, and bentonite.

15. The composition of claim 14, wherein the urea-ammonium sulfate adduct, the potassium sulfate, the ammonium chloride, and / or the ammonium sulfate is encapsulated by the bentonite.

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