Additive for the production of stabilized urea particles and its use

Abstract

The invention relates to a particulate composition comprising, or substantially consisting of, urea, an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor, and an additive, wherein the additive comprises components (i) and (ii): (i) a carboxylic acid or an anhydride, salt, or derivative thereof; preferably a carboxylic acid salt or a carboxylic acid derivative, more preferably a carboxylic acid salt; and (ii) a polar polymer; preferably a water-soluble polar polymer. The invention further relates to a process for preparing the particulate composition, an additive for a particulate composition, and the use of the particulate composition as a fertilizer.

Description

[0001] The invention relates to a particulate composition (urea particles) comprising, or substantially consisting of, urea, an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor, and an additive, wherein the additive comprises components (i) and (ii): (i) a carboxylic acid or an anhydride, salt, or derivative thereof; preferably a carboxylic acid salt or a carboxylic acid derivative, more preferably a carboxylic acid salt; and (ii) a polar polymer; preferably a water-soluble polar polymer. The invention further relates to a process for producing the particulate composition, an additive for a particulate composition, and the use of the particulate composition as a fertilizer.

[0002] In conventional methods for producing urea particles, such as granulation or prilling, formaldehyde-based additives, such as urea-formaldehyde solutions, are typically added to the urea melt / solution before solidification. These additives are needed to improve granulation or prilling and thus the quality of the urea particles.

[0003] Due to new regulations requiring higher nitrogen use efficiency (NUE) and a reduction in ammonia and greenhouse gas emissions, the demand for stabilized urea is increasing and will be much higher in the future.

[0004] To produce stabilized urea, certain active ingredients must be added to the urea, particularly urease inhibitors, usually in the form of an inhibitor formulation. The most commonly used class of urease inhibitors are thiophosphoric triamides. Examples of commercially available thiophosphoric triamides are N-(n-butyl)thiophosphoric triamide (NBPT) and N-(n-propyl)thiophosphoric triamide (NPPT). Nitrification inhibitors are also frequently used.

[0005] Nowadays, urea particles are primarily treated with inhibitor formulations by wholesalers, in small quantities, in a separate treatment process at mixing stations / systems. In this process, the urea particles are coated with the inhibitor formulations. After application, inhibitors such as thiophosphoric triamides are relatively stable at a storage temperature of 20°C and show degradation rates of 10-50% of the initially present inhibitor after one year of storage.

[0006] For the nitrogen utilization efficiency of stabilized urea, a minimum concentration of the inhibitor in the urea particles must be ensured at the time of application in the field. In most regions, the potential to reduce nitrogen losses must be demonstrated / verified.

[0007] For the treatment of large quantities of urea with inhibitors, it is more economical to perform the treatment upstream in the value chain, directly during granulation or prilling. For example, the urea can be treated with an inhibitor formulation as a melt / solution before entering the granulator / prilling tower, during the granulation process, or during cooling.

[0008] However, at a storage temperature of 20°C, an unexpectedly strong degradation of the inhibitor was observed, particularly of thiophosphoric triamides, when the urea particles are treated directly with the inhibitor during granulation or prilling, as described above.

[0009] This observed rapid degradation means that the required minimum concentration of the inhibitor in the treated urea product cannot be achieved economically or practically with this method at the time of application in the field. The stabilized urea product would have to be applied immediately after its production, i.e., without intermediate storage, which is logistically impossible. Alternatively, the inhibitor would have to be added in a very high concentration, which is unacceptable from both an economic and environmental perspective.

[0010] WO 2015 027244 A1 relates to a urea-nitrogen stabilizer composition and to methods, systems, and equipment for its production. The composition is incorporated into molten urea to obtain a composition containing less biuret, N-methyl-2-pyrrolidone (NMP), nitrogen stabilizer, and / or impurities, and yielding an effective solid fertilizer. These compositions are useful for odor control.

[0011] WO 2016 137815 A1 relates to a urea granulate with a nitrogen stabilizer and a carrier system that is essentially homogeneously distributed over the entire granule thickness. Various processes for the production of urea granulate are described, including pricking, fluidized bed, and drum granulation. The nitrogen stabilizer may contain a urease inhibitor such as NBPT, with the NBPT purity ranging from 90% to 99%. The nitrogen stabilizer may also contain a nitrification inhibitor such as dicyandiamide (DCD).

[0012] WO 2019 197183 A1 relates to a process for the production of a fertilizer composition comprising at least one urea-containing fertilizer and at least one (thio)phosphoric triamide.

[0013] WO 2022 136360 A2 relates to a process for producing a homogeneous, solid, particulate, urea-based composition comprising urea and one or more additives in a urea production plant.

[0014] WO 2002 020471 A2 relates to a method for improving the compressive strength and impact strength of urea granules by adding an additive comprising a polyvinyl compound of the general formula (CHX-CHY) n The process comprises a group of molecules, where n = 4–10,000 and X and Y are independently selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxylic acid group, an amine group, or an amide group. This process is characterized by the fact that it begins with a urea melt.

[0015] US 7,816,561 B2 relates to a method for improving compressive strength and reducing dust formation and the tendency of urea particles to clump together by adding an organic compound to the molten urea, wherein at least one carbohydrate and optionally a polyvinyl compound is added to the urea, and a composition intended to be used as a urea additive.

[0016] US 8,084,642 B2 relates to a method for improving the compressive strength, impact strength and compressibility of urea granules by adding a compound to the molten urea, wherein the compound comprises both a polyvinyl compound and an organic molecule consisting of 1 to 10 carbon atoms and 1 to 10 polar organic groups.

[0017] US 8,343,891 B2 relates to a method for improving the properties of urea granules, in particular their tendency to clump, dust formation and foaming in aqueous media, by adding an additive to the urea, wherein the additive comprises a carboxylic acid compound having the general formula XY-(Z)-COOH, wherein Z is a saturated or unsaturated hydrocarbon having 1-25 carbon atoms and X and Y are selected from the group consisting of a hydrogen atom or a polar organic functional group, and wherein the additive is added as a solution in a polar solvent to the urea granules, which are subsequently dried.

[0018] US 9,708,520 B2 generally concerns a concentrated sugar additive comprising (a) refined citric acid from the citric acid recovery industry and (b) a sugar-containing solution, which is useful for controlling dust emissions from particulate materials during manufacturing, handling, storage, or transportation. Such particulate materials include fertilizers, minerals, coal, etc.

[0019] EP 3 157 889 B1 relates to a particulate urea-containing composition, a process and apparatus for its production, its use as a fertilizer, as technical urea or feed additive, and the use of an additive for the production of a particulate urea-containing composition. The particulate composition contains (i) urea; and an additive comprising one or both of the following components: (ii) and (iii): (ii) a combination of at least one polymer or oligomer containing amino groups and at least one functionalized polyvinyl compound; (iii) at least one aliphatic C2-C8 dialdehyde; wherein the weight fraction of component (i) is > 60 wt.% and the weight fraction of the sum of components (ii) and (iii) in the composition is < 1 wt.%.The additive may also comprise a component (iv): (iv) at least one compound selected from the group consisting of aliphatic dicarboxylic acids, their salts and anhydrides, aliphatic tricarboxylic acids, their salts and anhydrides, aromatic dicarboxylic acids, their salts and anhydrides, and aldehydic acids, their salts and anhydrides, wherein the weight fraction of component (i) is > 60 wt.% and the weight fraction of the sum of components (ii), (iii) and (iv) in the composition is < 1 wt.%.

[0020] EP 3 484 601 B1 relates to a process for producing a NOx reducing agent AUS 32 solution (Diesel Exhaust Fluid) comprising at least the mixing of water and a particulate composition containing (i) urea; and an additive comprising component (ii): (ii) a combination of at least one polymer or oligomer containing amino groups and at least one functionalized polyvinyl compound; wherein the weight fraction of component (i) in the particulate composition is > 60 wt.% and the weight fraction of component (ii) in the particulate composition is < 1 wt.% and wherein a urea solution is obtained and the weight fraction of component (i) in the obtained urea solution is between 31 wt.% and 34 wt.%.

[0021] EP 3 380 446 B1 relates to a particulate composition containing (i) urea; and an additive comprising one or both of the components (ii) and (iii): (ii) a combination of at least one polymer or oligomer containing amino groups and at least one functionalized polyvinyl compound; (iii) at least one aliphatic C2-C8 dialdehyde; and an additive comprising one or more of the components (iv) to (vi): (iv) sulfur; (v) ammonium sulfate; (vi) at least one trace element; wherein the weight fraction of component (i) is > 10 wt.% and the weight fraction of the sum of components (ii) and (iii) in the composition is < 1 wt.%, the use of this additive for the production of the particulate, urea-containing composition, the process and apparatus for producing the composition, and its use as a fertilizer.

[0022] The known urea particles are not satisfactory in every respect and there is a need for improvements, especially with regard to storage stability.

[0023] It is an object of the invention to provide urea particles containing additives other than formaldehyde-based additives, as well as urease inhibitors, in particular thiophosphoric triamides, and / or nitrification inhibitors, and which are characterized by improved storage stability, particularly with regard to the inhibitor content. The urea particles should be easy and inexpensive to produce.

[0024] This problem is solved by the subject matter of the patent claims.

[0025] It was surprisingly found that the degradation of the inhibitor, particularly thiophosphoric triamides, can be significantly reduced, i.e., storage stability can be significantly improved, when an additive with low reactivity towards the inhibitor is used as a replacement for a formaldehyde-based additive. Additives that are neither acidic nor acid-forming are particularly suitable.

[0026] Furthermore, it was surprisingly found that an additive combining a carboxylic acid salt or derivative, in particular calcium citrate, magnesium citrate, sodium citrate, or potassium citrate, with a polar polymer, especially polyvinyl alcohol, is particularly suitable. When such an additive is added to a urea melt and / or urea solution before granulation / prilling, urea particles can be obtained that meet the usual quality criteria and exhibit improved storage stability (inhibitor degradation rate). Urea particles containing such an additive and combined with an inhibitor, preferably a thiophosphoric triamide such as...Samples treated with N-(n-butyl)thiophosphoric triamide (NBPT) or N-(n-propyl)thiophosphoric triamide (NPPT), or with inhibitor formulations containing these inhibitors, either during or after granulation / pricking, exhibited satisfactorily low inhibitor degradation rates.

[0027] A first aspect of the invention relates to a particulate composition comprising or substantially consisting of urea, an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor, and an additive, wherein the additive comprises components (i) and (ii): (i) a carboxylic acid salt or a carboxylic acid derivative, preferably a carboxylic acid salt; and (ii) a polar polymer; preferably a water-soluble polar polymer.

[0028] For descriptive purposes, "essentially consisting of" means that the presence of other components in the mixture is not excluded, provided they do not significantly alter essential characteristics of the mixture. Preferably, "essentially consisting of" means that the expressly listed components / ingredients of the mixture constitute at least 95% by weight of the mixture, more preferably at least 96% by weight, more preferably at least 97% by weight, most preferably at least 98% by weight, and particularly at least 99% by weight.

[0029] For descriptive purposes, "particulate" means a physical form which can also be described as granulated, prilled, crystalline, compacted, pulverized, and the like, wherein the "particulate" composition exists as a composition in a small, uniform form (particles) as a multitude of small, solid particles, i.e., particles whose dimensions are small compared to the scale of the particulate substance as a whole (i.e., as granules, prills, crystallites, pellets, powder, or pulverized powder). Preferably, the particulate composition exists as granules, i.e., as a granular substance ("granular matter"). For descriptive purposes, a "granule" consists of many individual, small, solid particles, such as grains. Preferably, each grain comprises seed, e.g., recycled undersize seed, and urea sprayed onto the seed.

[0030] Preferably the mean particle size (D50 (mass-averaged)) of the particulate composition is in the range of 0.5 mm to 5.0 cm; preferably 1.0 mm to 1.0 cm, more preferably 1.0 mm to 6.0 mm, even more preferably 2.0 mm to 5.0 mm, and most preferably 2.0 mm to 4.0 mm; preferably determined by sieve analysis according to DIN EN 1235:2003-08.

[0031] The particulate composition according to the invention comprises urea.

[0032] Preferably the urea content is at least 50 wt.%; preferably at least 60 wt.%, more preferably at least 70 wt.%, even more preferably at least 80 wt.%, most preferably at least 90 wt.%, and in particular at least 95 wt.%, in each case relative to the total weight of the particulate composition.

[0033] The particulate composition according to the invention further comprises an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor.

[0034] The urease inhibitor is preferably selected from the group consisting of N-(n-butyl)thiophosphoric triamide (NBPT), N-(n-propyl)thiophosphoric triamide (NPPT), hydroquinone, phosphorus triamide, p-benzoquinone, cyclohexyl phosphate triamide, and hexaamidocyclotriphosphazene; preferably N-(n-butyl)thiophosphoric triamide and N-(n-propyl)thiophosphoric triamide.

[0035] The nitrification inhibitor is preferably selected from the group consisting of dicyandiamide, 1-methylpyrazole-1-hydroxyamide, 3-methylpyrazole, ethylene urea, chlorazole, 4-aminotriazole, thiourea, acetylene, 2-ethinylpyridine, sulfathiazole, amidinothiourea, 1-amino-2,4-dimethylpyrazole phosphate, thiosulfates, for example sodium thiosulfate, calcium carbide, 2,5-chloroaniline, 3-acetanilide, toluene, carbon disulfide, phenylacetylene, 2-propyn-1-ol, and phenethylphosphonium diamide.

[0036] The particle-shaped composition according to the invention preferably comprises a urease inhibitor; preferably a thiophosphoric triamide; preferably N-(n-butyl)thiophosphoric triamide (NBPT) and / or N-(n-propyl)thiophosphoric triamide (NPPT).

[0037] The composition may also contain several urease inhibitors and / or several nitrification inhibitors. A composition with at least one urease inhibitor (or with several urease inhibitors) and additionally at least one nitrification inhibitor (or with several nitrification inhibitors) is therefore preferred.

[0038] In preferred embodiments, the particulate composition comprises two urease inhibitors; preferably two thiophosphoric triamides; preferably N-(n-butyl)thiophosphoric triamide (NBPT) and N-(n-propyl)thiophosphoric triamide (NPPT).

[0039] In preferred embodiments, the inhibitor content is at most 1.0 wt.%; preferably at most 0.5 wt.%, more preferably at most 0.1 wt.%, and even more preferably at most 0.05 wt.%; in each case based on the sum of all inhibitors contained in the particulate composition and relative to the total weight of the particulate composition.

[0040] In preferred embodiments, the inhibitor content is in the range of 0.005 to 0.5 wt.%; preferably 0.01 to 0.1 wt.%, more preferably 0.02 to 0.08 wt.%, and even more preferably 0.04 to 0.06 wt.%; in each case based on the sum of all inhibitors contained in the particulate composition and relative to the total weight of the particulate composition.

[0041] Preferably, the particulate composition contains no solvent and no stabilizer for the inhibitor (or at most unavoidable residual amounts thereof). Alternatively, the particulate composition according to the invention can also contain at least some of the solvent and / or the stabilizer for the inhibitor.

[0042] The particulate composition according to the invention comprises an additive, wherein the additive comprises components (i) and (ii): (i) a carboxylic acid salt or a carboxylic acid derivative, preferably a carboxylic acid salt; and (ii) a polar polymer; preferably a water-soluble polar polymer.

[0043] For the purposes of description, an "additive" is a composition that can advantageously be added to (conventional) fertilizers to improve their properties. A fertilizer additive is generally not a fertilizer as such. The primary function of the additive according to the invention is preferably to improve the production, storage properties, and application of the inhibitor-treated fertilizer or fertilizer granules, in particular the granulation behavior and product quality (crushing strength, caking, and bulk density) of the granules.

[0044] The particulate composition according to the invention comprises urea, the inhibitor, and components (i) and (ii) of the additive. For the purposes of description, the individual components (i) and (ii) of the additive can be added together or separately during the preparation of the particulate composition. For example, one of the components (i) or (ii) can be added separately to the urea or the inhibitor.

[0045] Preferably, the additive does not react with thiophosphoric triamides, thereby degrading or otherwise reducing the activity of the inhibitor. Preferably, the additive has a stabilizing effect on the inhibitor.

[0046] Preferably, the additive is in the form of a solid, a liquid or a suspension; preferably as a solution.

[0047] Preferably, the additive is a mixture of water-soluble substances; more preferably, an aqueous solution. In particularly preferred embodiments, the additive is an aqueous solution comprising (i) tricalcium dicitrate, trimagnesium dicitrate, trisodium citrate, or tripotassium citrate, and (ii) polyvinyl alcohol.

[0048] In preferred embodiments, the additive also contains urea.

[0049] The additive according to the invention comprises a carboxylic acid salt or a carboxylic acid derivative, preferably a carboxylic acid salt.

[0050] Preferably, the carboxylic acid salt or carboxylic acid derivative is a salt or a derivative of an aliphatic carboxylic acid, a cyclic carboxylic acid, an unsaturated carboxylic acid or an aromatic carboxylic acid.

[0051] Preferably, the carboxylic acid is an aliphatic carboxylic acid.

[0052] Preferably, the carboxylic acid salt or carboxylic acid derivative is a salt or a derivative of a saturated carboxylic acid.

[0053] Preferably, the carboxylic acid salt or carboxylic acid derivative is a salt or a derivative of an acyclic carboxylic acid.

[0054] In preferred embodiments, the carboxylic acid is a monocarboxylic acid; preferably an aliphatic monocarboxylic acid.

[0055] In other preferred embodiments, the carboxylic acid salt or carboxylic acid derivative is a salt or derivative of a carboxylic acid having two or more carboxyl groups; preferably a dicarboxylic acid or a tricarboxylic acid; more preferably an aliphatic dicarboxylic acid or tricarboxylic acid.

[0056] In preferred embodiments, the carboxylic acid salt or the carboxylic acid derivative is a salt or a derivative of a dicarboxylic acid; preferably an aliphatic dicarboxylic acid.

[0057] In particularly preferred embodiments, the carboxylic acid salt or the carboxylic acid derivative is a salt or a derivative of a tricarboxylic acid; preferably an aliphatic tricarboxylic acid; more preferably an aliphatic saturated tricarboxylic acid; even more preferably an aliphatic saturated acyclic tricarboxylic acid.

[0058] Preferably, the carboxylic acid salt or carboxylic acid derivative is a salt or a derivative of a carboxylic acid selected from citric acid, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, cortic acid, azelaic acid, sebacic acid, agaricic acid, hemimellitic acid, trimellitic acid, trimesic acid, γ-carboxyglutamic acid, polyacrylic acid, and alginic acid; preferably citric acid.

[0059] The carboxylic acid salt or derivative can be a salt or derivative of a polymeric carboxylic acid. In preferred embodiments, the carboxylic acid salt or derivative is neither a salt nor a derivative of a polymeric carboxylic acid.

[0060] In preferred embodiments, the additive according to the invention comprises as component (i) a carboxylic acid derivative as described above.

[0061] For descriptive purposes, a "carboxylic acid derivative" is an organic compound whose functional group is formally derived from a carboxyl group (-COOH). Carboxylic acid derivatives differ from other carbonyl compounds in that, in addition to an organic residue (in the case of formic acid derivatives, this organic residue is replaced by a hydrogen atom), a heteroatom is bonded to the carbonyl carbon. In contrast, in aldehydes, an organic residue and a hydrogen atom are bonded to the carbonyl group, or two hydrogen atoms in formaldehyde, two organic residues in ketones, and two heteroatoms in carbonic acid derivatives.

[0062] Preferably, the carboxylic acid derivative is selected from the group consisting of carboxylic acid esters, carboxylic acid amides, and carboxylic acid imides. For the purpose of description, carboxylic acid diesters, carboxylic acid triesters, carboxylic acid diamides, carboxylic acid triamides, carboxylic acid diimides, and carboxylic acid triimides are also included.

[0063] In particularly preferred embodiments, the additive according to the invention comprises as component (i) a carboxylic acid salt as described above.

[0064] For the purposes of description, a "carboxylic acid salt" is a salt of an organic carboxylic acid, including monobasic, dibasic, and tribasic salts of the organic carboxylic acid and their hydrates. The carboxylic acid can be present in a partially or completely deprotonated form. Monocarboxylic acids possess one carboxyl group and preferably form monobasic salts. Dicarboxylic acids possess two carboxyl groups and preferably form monobasic or dibasic salts. Tricarboxylic acids possess three carboxyl groups and preferably form monobasic, dibasic, or tribasic salts. Preferably, the carboxylic acid is present in a completely deprotonated form. For example, preferred salts of citric acid according to the invention are tricalcium dicitrate, trimagnesium dicitrate, trisodium citrate, or tripotassium citrate, or their hydrates.

[0065] Preferably, the carboxylic acid salt is a salt of a completely deprotonated carboxylic acid; particularly preferably a completely deprotonated aliphatic saturated tricarboxylic acid.

[0066] For descriptive purposes, “fully deprotonated carboxylic acid” preferably means that all carboxyl groups of the carboxylic acid are deprotonated.

[0067] Preferably, the carboxylic acid salt comprises a cation selected from the group consisting of K + , N / a + , NH4 + , Ca 2+ , Mg 2+ , Fe 2+ , Fe 3+ , Zn 2+ , Al 3+ , Mn 2+ , Mn 4+ , Cu 2+ , Li + , Se 2+ , Se 4+ , Se 6+ , B 3+ , Ni 2+ , Mo 2+ , Mo 3+ , Mo 4+ , Mo 6+ , Cu + , Ag + , Pt 2+ , Ru 2+ , Co 3+ , Cr 3+ , Pb 2+ , Hg 2+ , and Ba 2+; preferably selected from K + , N / a + , NH4 + , Ca 2+ , Mg 2+ , Fe 2+ , Fe 3+ , Zn 2+ , Al 3+ , Mn 2+ , Mn 4+ , Cu 2+ , Li + , Se 2+ , Se 4+ , Se 6+ , B 3+ , Ni 2+ , Mo 2+ , Mo 3+ , Mo 4+ , and Mo 6+ ; preferred selected from K + , N / a + , NH4 + , Ca 2+ , Mg 2+ , Fe 2+ , Fe 3+ , Zn 2+ , Al 3+ , Mn 2+ , Mn 4+ , Cu 2+ , Li + , Se 4+ , Se 6+ , B 3+ , and Ni 2+ ; even more preferably selected from K + , N / a + , NH4 + , Mg 2+ and Ca 2+ , most preferably selected from K + , N / a + , and NH4 + , and especially K + .

[0068] The carboxylic acid salt calcium citrate, magnesium citrate, sodium citrate, or potassium citrate is preferred; potassium citrate is preferred. The carboxylic acid salt tricalcium dicitrate, trimagnesium dicitrate, trisodium citrate, or tripotassium citrate is preferred; trisodium citrate or tripotassium citrate is even more preferred; tripotassium citrate is particularly preferred.

[0069] Preferably, the cations are present only as counterions within the carboxylic acid salt. Their concentration therefore preferably depends directly on the type and concentration of the carboxylic acid. The particulate composition according to the invention preferably contains no other cation source besides the carboxylic acid salt.

[0070] Preferably, the carboxylic acid salt or the carboxylic acid derivative is water-soluble.

[0071] For the purpose of describing carboxylic acid salts and carboxylic acid derivatives, "water-soluble" means that a solution can be obtained in water which has a concentration of at least 800 mg / L of the carboxylic acid salt or the carboxylic acid derivative at room temperature (20°C).

[0072] Preferably the carboxylic acid salt or the carboxylic acid derivative is biodegradable.

[0073] For the purpose of describing carboxylic acid salts and carboxylic acid derivatives, “biodegradable” means that at least 60 wt.% of the carboxylic acid salt or carboxylic acid derivative is biodegraded, in particular by a process in accordance with OECD 301 A or B, preferably within 28 days and at a concentration of 10 to 40 mg DOC / L (DOC = “dissolved organic carbon”).

[0074] Preferably, the carboxylic acid salt or the carboxylic acid derivative is not acidic or acid-forming.

[0075] In preferred embodiments, the total content of carboxylic acid salt or carboxylic acid derivative is in the range of 0.01 to 1.0 wt.%; preferably 0.02 to 0.8 wt.%, more preferably 0.02 to 0.6 wt.%, even more preferably 0.02 to 0.4 wt.%, and most preferably 0.02 to 0.2 wt.%; in each case relative to the total weight of the particulate composition.

[0076] In preferred embodiments, component (i) comprises, in addition to the carboxylic acid salt or the carboxylic acid derivative, a carboxylic acid as described above and / or a carboxylic acid anhydride of a carboxylic acid as described above. In these preferred embodiments, the carboxylic acid together with the carboxylic acid salt preferably forms a buffer system; preferably with a pH value in the range of 4.0 to 7.0, more preferably from 5.0 to 7.0, and even more preferably from 6.0 to 7.0.

[0077] The additive according to the invention comprises a polar polymer.

[0078] For descriptive purposes, "polar polymer" means a polymer with a polar group. The polar group refers to a functional group that forms a dipole with an uneven center of positive and negative charge due to a distorted distribution of electron clouds resulting from a difference in the electronegativity of the atoms that make up the functional group. Examples of polar groups include an ether group, a carboxyl group, a sulfone group, a phosphate group, a formyl group, an amino group, an amide group, a hydroxyl group, a cyano group, an epoxy group, an ester group, a carbonate group, and a lactone group.Examples of polar polymers include polyethers, polyacrylonitrile, polyvinyl carbonate, polycarbonate, polyester, and polymethyl methacrylate, each containing an ether bond in a repeating unit, or polyvinyl alcohols, each containing a hydroxyl group in a repeating unit. A polar polymer typically has a dipole moment greater than 0 D at 25°C.

[0079] Preferably the polar polymer is a vinyl polymer, a polyester, a polyether or a polyacrylate; preferably a vinyl polymer, a polyester or a polyether.

[0080] For the purposes of description, "vinyl polymer" also includes functionalized polyvinyl compounds. According to the invention, functionalized polyvinyl compounds include, in particular, compounds based on the repeating unit (CHX-CHY). nconsidering, wherein X is selected from the group consisting of H, OH, COOH, COR, CH2OH and CH2OR and Y is selected from the group consisting of OH, COOH, COR, CH2OH and CH2OR and wherein R is each independently for alkyl, in particular C 1-6 -Alkyl, or aryl, in particular phenyl or pyridyl, which can stand unsubstituted or optionally with 1, 2, 3, 4 or 5 substituents independently selected from the group consisting of F, Cl, Br, CF3, C 1-6 -Alkyl, C 1-6 -Alkoxy may be substituted.

[0081] Preferably, the polar polymer is selected from the group consisting of polyvinyl alcohol (PVOH), polyethylene glycol (PEG), polylactic acid (PLA), polyethylene glycol esters, butenediol-vinyl alcohol copolymer (BVOH), polyvinylpyrrolidone (PVP), and polyacrylamide (PAM); preferably polyvinyl alcohol (PVOH), polyethylene glycol (PEG), polylactic acid (PLA), and polyethylene glycol esters; preferably polyvinyl alcohol (PVOH).

[0082] Preferably, the polar polymer has a molecular weight in the range of 200 to 2,000,000 g / mol; preferably 400 to 1,000,000 g / mol, more preferably 600 to 500,000 g / mol, even more preferably 800 to 250,000 g / mol, most preferably 1000 to 100,000 g / mol, and particularly 1200 to 10,000 g / mol.

[0083] Preferably, the polar polymer is water-soluble.

[0084] For the purpose of describing polar polymers, "water-soluble" means that at room temperature (20°C) an aqueous solution of the polar polymer is present which contains at least 1 g / L of the polar polymer.

[0085] Preferably, the polar polymer is biodegradable.

[0086] For the purpose of describing polar polymers, “biodegradable” means that at least 60 wt.% of the polar polymer is biodegradable, in particular by a process in accordance with OECD 301 A or B, preferably within 28 days and at a concentration of 10 to 40 mg DOC / L (DOC = “dissolved organic carbon”).

[0087] Preferably, the polar polymer is not harmful to the environment.

[0088] Preferably, the particulate composition according to the invention is not acidic with respect to its pH value. Preferably, the pH value of an aqueous solution of the particulate composition (including the polar polymer) with a particulate composition content of 10 wt% does not fall below a pH value of 7.0 immediately after dissolution. Preferably, the pH value of an aqueous solution of the particulate composition (including the polar polymer) with a particulate composition content of 10 wt% immediately after dissolution is at least 8.0; more preferably in the range of 8.0 to 10. Preferably, the particulate composition does not comprise any acidic components.

[0089] Preferably, the polar polymer is non-acidic.

[0090] Preferably, an aqueous solution of the polar polymer with a polar polymer content of 5.0 wt.% has a pH value of at least 5.0 immediately after dissolution, more preferably in the range of 5.0 to 6.5.

[0091] Preferably, the polar polymer has a pKa value of at least 7.0, more preferably at least 10.0, and particularly preferably at least 12.

[0092] In preferred embodiments, the total content of polar polymer is in the range of 0.001 to 1.0 wt.%; preferably 0.002 to 0.8 wt.%, more preferably 0.003 to 0.6 wt.%, even more preferably 0.004 to 0.4 wt.%, and most preferably 0.005 to 0.2 wt.%; in each case relative to the total weight of the particulate composition.

[0093] Preferably, the carboxylic acid salt or carboxylic acid derivative and the polar polymer are different.

[0094] In preferred embodiments, the total additive content, i.e., components (i) and (ii), is at least 0.02 wt.%; preferably at least 0.04 wt.%, more preferably at least 0.06 wt.%, even more preferably at least 0.08 wt.%, and most preferably at least 0.1 wt.%; in each case relative to the urea content in the particulate composition.

[0095] In preferred embodiments, the total additive content, i.e., components (i) and (ii), is at most 1.5 wt.%, preferably at most 1.0 wt.%; preferably at most 0.8 wt.%, more preferably at most 0.6 wt.%, more preferably at most 0.4 wt.%, and most preferably at most 0.2 wt.%; in each case relative to the urea content in the particulate composition.

[0096] In preferred embodiments, the total additive content, i.e., components (i) and (ii), is in the range of 0.12 ± 0.1 wt.%; preferably 0.12 ± 0.08 wt.%, more preferably 0.12 ± 0.06 wt.%, even more preferably 0.12 ± 0.04 wt.%, and most preferably 0.12 ± 0.02 wt.%, in each case relative to the urea content in the particulate composition.

[0097] In preferred embodiments, the total content of additive, i.e., components (i) and (ii), is at least 0.02 wt.%; preferably at least 0.04 wt.%, more preferably at least 0.06 wt.%, even more preferably at least 0.08 wt.%, and most preferably at least 0.1 wt.%; in each case relative to the total weight of the particulate composition.

[0098] In preferred embodiments, the total content of additive, i.e., components (i) and (ii), is at most 1.5 wt.%, preferably at most 1.0 wt.%; preferably at most 0.8 wt.%, more preferably at most 0.6 wt.%, more preferably at most 0.4 wt.%, and most preferably at most 0.2 wt.%; in each case relative to the total weight of the particulate composition.

[0099] In preferred embodiments, the total additive content, i.e., components (i) and (ii), is in the range of 0.12 ± 0.1 wt.%; preferably 0.12 ± 0.08 wt.%, more preferably 0.12 ± 0.06 wt.%, even more preferably 0.12 ± 0.04 wt.%, and most preferably 0.12 ± 0.02 wt.%; in each case relative to the total weight of the particulate composition.

[0100] In preferred embodiments, the relative weight ratio of component (i) to component (ii) is in the ratio of 10:1 to 1:10, preferably 8:1 to 1:8, more preferably 6:1 to 1:6, even more preferably 4:1 to 1:4, most preferably 3:1 to 1:3 and in particular 2:1 to 1:2.

[0101] In preferred embodiments, the total content of additive, i.e., components (i) and (ii), and inhibitor is at most 1.5 wt.%, preferably at most 1.0 wt.%; preferably at most 0.8 wt.%, more preferably at most 0.6 wt.%, more preferably at most 0.4 wt.%, and most preferably at most 0.2 wt.%; in each case relative to the urea content in the particulate composition.

[0102] In preferred embodiments, the particulate composition according to the invention comprises one or more additives; preferably the additives contain one or more of the following components: - Sulfur; - Ammonium sulfate; - at least one trace element.

[0103] The additive can comprise either (elemental) sulfur or ammonium sulfate, or at least one trace element. Likewise, the additive can comprise any possible combination of the aforementioned components or may also contain other constituents. The sulfur can be used in its elemental form or as a component of a compound. For example, the additive can comprise sulfur in the form of sulfates. Trace elements are preferably those elements that are necessary for a living organism and are typically present in organisms in mass fractions of less than 50 mg / kg. Trace elements can include, for example, aluminum, boron, chlorine, iron, copper, manganese, molybdenum, and / or zinc. A person skilled in the art recognizes that the term trace element encompasses both a single element and any possible mixture of two or more elements.

[0104] In preferred embodiments, the particulate composition according to the invention comprises ammonium sulfate.

[0105] Preferably, the ammonium sulfate content is at most 1.0 wt.%; preferably at most 0.75 wt.%, more preferably at most 0.5 wt.%, and even more preferably at most 0.3 wt.%; in each case relative to the total weight of the particulate composition.

[0106] The particulate composition according to the invention may contain further components in addition to those already mentioned. For example, the particulate composition according to the invention may contain water, e.g., in an amount of 0.05 to 0.5 wt.%, in particular 0.1 to 0.3 wt.%, and byproducts of urea synthesis such as biuret or NH3, or antifoaming agents such as mono- and diglycerides of fatty acids and dimethylpolysiloxane. Typically, the proportion of byproducts does not exceed 1.5 wt.%, in particular not more than 1.25 wt.%.

[0107] Another aspect of the invention relates to an additive as described above comprising components (i) and (ii) for producing a particulate composition as described above.

[0108] Another aspect of the invention relates to the use of an additive as described above for the production of a particulate composition as described above.

[0109] Another aspect of the invention relates to a method for producing a particulate composition as described above, wherein the method comprises the steps: (a) Providing an inhibitor composition containing an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor; (b) Providing a urea-containing solution and / or melt; (c) Granulating or pricking the urea-containing solution and / or melt to obtain a particulate composition; (d) optional pre-cooling of the particulate composition; (e) optionally classifying the particulate composition to obtain particle fractions; (f) optionally separating a particle fraction obtained in step (e); and returning this separated particle fraction to a granulation or pricking device used in step (c) (optionally after comminution of the particles of this particle fraction); and (g) optional post-cooling of the particulate composition; wherein component (i) and component (ii) of an additive as described above are added independently of each other; preferably to the provided inhibitor composition or to the urea-containing solution and / or melt; wherein the inhibitor composition is added to the urea-containing solution and / or melt or brought into contact with the particulate composition.

[0110] The inhibitor composition is preferred, (i) after step (c) and before step (d); (ii) during step (d); (iii) after step (d) and before step (e); (iv) during step (e); (v) after step (e) and before step (f); (vi) during step (f); (vii) after step (f) and before step (g); (viii) during step (g); and / or (ix) after step (g); brought into contact with the particulate composition.

[0111] In preferred embodiments, the inhibitor composition is added to the urea-containing solution and / or melt before or during step (c) of the process according to the invention.

[0112] In preferred embodiments, the inhibitor composition is added to the urea-containing solution and / or melt as a liquid or suspension, preferably as a solution.

[0113] Particularly pronounced advantages arise when granulation is carried out as fluidized bed granulation.

[0114] Preferably, the temperature of the urea-containing solution and / or melt is at least 120°C; preferably at least 125°C, and more preferably at least 130°C.

[0115] The inhibitor composition is preferably liquid, preferably a solution.

[0116] Typically, an inhibitor composition contains a solvent and a stabilizer for the inhibitor. However, the inhibitor composition can also contain the components in undissolved form. The particulate composition according to the invention can contain at least some of the solvent and / or the stabilizer for the inhibitor.

[0117] In preferred embodiments, the additive, i.e., components (i) and (ii), is added to the urea-containing solution and / or melt before or during step (c) of the process according to the invention.

[0118] Preferably the additive, i.e. components (i) and (ii), is added in step (c) of the method according to the invention.

[0119] Preferably, the additive is added in step (c) to the urea-containing solution and / or melt; preferably before the urea-containing solution and / or melt solidifies.

[0120] The additive is preferably added as a liquid or suspension, preferably before or during step (c); preferably as a solution; more preferably as an aqueous solution.

[0121] In preferred embodiments, the additive also contains urea.

[0122] The additive is preferably added as an aqueous solution or aqueous suspension, preferably before or during step (c); more preferably as a urea-containing aqueous solution.

[0123] Alternatively, the additive can also be added to a urea melt or urea solution as a solid.

[0124] In embodiments, the polar polymer is added as the reactive monomer of the polymer, wherein the reactive monomer preferably polymerizes in situ, thereby forming the polar polymer. Preferably, the monomer does not react with the inhibitor.

[0125] In preferred embodiments, the addition of component (i) and component (ii) to the urea-containing solution and / or melt is carried out together in one step; preferably in a solution.

[0126] In other preferred embodiments, component (i) and component (ii) are added to the urea-containing solution and / or melt sequentially. Preferably, component (i) and component (ii) are added to the urea-containing solution and / or melt in separate solutions. Preferably, component (i) and component (ii) are added to the urea-containing solution and / or melt sequentially. In preferred embodiments, component (i) is added before component (ii). In other preferred embodiments, component (ii) is added before component (i).

[0127] Preferably, the additive is added to the urea-containing solution and / or melt separately from the addition of the inhibitor composition to the urea-containing solution and / or melt.

[0128] Another aspect of the invention relates to the use of a particulate composition as described above as a fertilizer.

[0129] The following examples serve to illustrate the invention, but are not to be interpreted restrictively. Example 1:

[0130] A particulate composition comprising urea, an inhibitor, and an additive was prepared. To this end, polyvinyl alcohol and tricalcium dicitrate (as the hydrate) were first mixed, and the resulting suspension was added to a highly concentrated urea solution (97 wt%) at 125 °C to 135 °C. The amount of suspension was 0.12 wt% relative to the urea solution. An inhibitor composition (Limus) was used.® BASF Direct, containing a combination of NPPT and NBPT, was added to the urea-containing melt at a constant rate via a metering pump. The resulting mixture of highly concentrated urea solution and additive was fed into a fluidized bed granulator, where the particulate composition was formed. The flow rate of the inhibitor formulation was adjusted to achieve a concentration of 1.2 L / t of final product.

[0131] Upon subsequent storage of the particulate composition for three months at storage temperatures between 20 °C and 40 °C, no degradation of the inhibitor was observed. However, when urea-formaldehyde was used as an additive, increased degradation of the inhibitor was observed. This was determined by comparing the relative amount of the active ingredient (inhibitor) concentration to the concentration at the time of the first measurement.

[0132] Fig.This figure shows the degradation of the inhibitor when using the additive containing polyvinyl alcohol and calcium citrate, and when using urea-formaldehyde (UF) as the additive. It depicts the decrease in the percentage of inhibitor in the product over time, relative to the amount present immediately after production, during storage. A decrease to approximately 20% was observed for urea fertilizer granules with the conventional additive from a pilot plant at low storage temperature over several months. A decrease to approximately 40% was observed for urea fertilizer granules with the conventional additive from a commercial plant at low storage temperature over several months.A decrease of less than 10% was observed during the storage of urea fertilizer granules over several months for granules with the additive according to the invention from a pilot plant at three different storage temperatures. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2015 027244 A1

[0010] WO 2016 137815 A1

[0011] WO 2019 197183 A1

[0012] WO 2022 136360 A2

[0013] WO 2002 020471 A2

[0014] US 7,816,561 B2

[0015] US 8,084,642 B2

[0016] US 8,343,891 B2

[0017] US 9,708,520 B2

[0018] EP 3 157 889 B1

[0019] EP 3 484 601 B1

[0020] EP 3 380 446 B1

[0021]

Claims

[1] Particle composition comprising or substantially consisting of urea, an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor, and an additive, wherein the additive comprises components (i) and (ii): (i) a carboxylic acid salt or a carboxylic acid derivative, preferably a carboxylic acid salt; and (ii) a polar polymer; preferably a water-soluble polar polymer. [2] The particulate composition according to claim 1, wherein the urea content is at least 50 wt.%; preferably at least 60 wt.%, more preferably at least 70 wt.%, more preferably at least 80 wt.%, most preferably at least 90 wt.%, and in particular at least 95 wt.%; in each case relative to the total weight of the particulate composition. [3] The particulate composition according to claim 1 or 2, comprising a urease inhibitor; preferably a thiophosphoric triamide; preferably N-(n-butyl)thiophosphoric triamide (NBPT) and / or N-(n-propyl)thiophosphoric triamide (NPPT). [4] The particulate composition according to any of the preceding claims, wherein the carboxylic acid salt or the carboxylic acid derivative is a salt or a derivative of a carboxylic acid having two or more carboxyl groups; preferably wherein the carboxylic acid salt or the carboxylic acid derivative is a salt or a derivative of a dicarboxylic acid or a tricarboxylic acid; more preferably an aliphatic dicarboxylic acid or tricarboxylic acid; even more preferably an aliphatic saturated dicarboxylic acid or tricarboxylic acid; and in particular an aliphatic saturated acyclic dicarboxylic acid or tricarboxylic acid. [5] The particulate composition according to any of the preceding claims, wherein the carboxylic acid derivative is selected from the group consisting of carboxylic acid esters, carboxylic acid amides, and carboxylic acid imides. [6] The particulate composition according to any one of the preceding claims, wherein the carboxylic acid salt is calcium citrate, magnesium citrate, sodium citrate or potassium citrate; tricalcium dicitrate, trimagnesium dicitrate, trisodium citrate or tripotassium citrate; preferably trisodium citrate or tripotassium citrate; particularly preferably tripotassium citrate. [7] The particulate composition according to any of the preceding claims, wherein the carboxylic acid salt or the carboxylic acid derivative is not acidic or acid-forming. [8] The particulate composition according to any of the preceding claims, wherein the total content of carboxylic acid salt or carboxylic acid derivative is in the range of 0.01 wt.% to 1.5 wt.%, preferably 0.01 to 1.0 wt.%, more preferably 0.02 to 0.8 wt.%; more preferably 0.02 to 0.6 wt.%, more preferably 0.02 to 0.4 wt.%, and more preferably 0.02 to 0.2 wt.%, and most preferably 0.05 to 0.2 wt.%; in each case relative to the total weight of the particulate composition. [9] The particulate composition according to any one of the preceding claims, wherein the polar polymer is a vinyl polymer, a polyester, a polyether or a polyacrylate; preferably a vinyl polymer, a polyester or a polyether; more preferably the polar polymer is selected from the group consisting of polyvinyl alcohol (PVOH), polyethylene glycol (PEG), polylactic acid (PLA), polyethylene glycol esters, butenediol-vinyl alcohol copolymer (BVOH), polyvinylpyrrolidone (PVP), and polyacrylamide (PAM); more preferably polyvinyl alcohol (PVOH), polyethylene glycol (PEG), polylactic acid (PLA), and polyethylene glycol esters, and even more preferably polyvinyl alcohol (PVOH). [10] The particulate composition according to any of the preceding claims, wherein the polar polymer is water-soluble and / or biodegradable. [11] The particulate composition according to any of the preceding claims, wherein the total polymer content is in the range of 0.001 to 1.0 wt.%; preferably 0.002 to 0.8 wt.%, more preferably 0.003 to 0.6 wt.%, 0.004 to 0.4 wt.%, and most preferably 0.005 to 0.2 wt.%; in each case relative to the total weight of the particulate composition. [12] The particulate composition according to any of the preceding claims, comprising one or more additives; preferably the additives comprise one or more of the following components: - Sulfur; - Ammonium sulfate; - at least one trace element. [13] An additive as defined in any one of the preceding claims comprising components (i) and (ii) for producing a particulate composition according to any one of the preceding claims. [14] Use of an additive according to claim 13 for the production of a particulate composition according to any one of claims 1 to 12. [15] A method for producing a particulate composition according to any one of claims 1 to 12, wherein the method comprises the steps: (a) Providing an inhibitor composition containing an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor; (b) Providing a urea-containing solution and / or melt; (c) Granulating or pricking the urea-containing solution and / or melt to obtain a particulate composition; (d) optional pre-cooling of the particulate composition; (e) optionally classifying the particulate composition to obtain particle fractions; (f) optionally separating a particle fraction obtained in step (e); and returning this separated particle fraction to a granulation or pricking device used in step (c); and (g) optionally post-cooling the particulate composition; wherein component (i) and component (ii) of an additive according to claim 13 are added independently of each other; preferably to the provided inhibitor composition or to the urea-containing solution and / or melt; wherein the inhibitor composition is added to the urea-containing solution and / or melt or brought into contact with the particulate composition. [16] The method according to claim 15, wherein the temperature of the urea-containing solution and / or melt is at least 120°C; preferably at least 125°C, and more preferably at least 130°C. [17] The method according to claim 15 or 16, wherein the addition of the additive to the urea-containing solution and / or melt takes place before or during step (c); preferably in step (c); more preferably before the solidification of the urea-containing solution and / or melt. [18] The method according to any one of claims 15 to 17, wherein - the additive is added, preferably before or during step (c), as a solid, liquid or suspension; preferably as a solution; more preferably as an aqueous solution; even more preferably as a urea-containing aqueous solution; and / or - the inhibitor composition is added, preferably before or during step (c), as a liquid or suspension to the urea-containing solution and / or melt, preferably as a solution. [19] The method according to any one of claims 15 to 18, wherein the addition of component (i) and component (ii) to the urea-containing solution and / or melt is carried out together in one step or successively. [20] Use of a particulate composition according to any one of claims 1 to 12 as a fertilizer.

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