High-strength fertilizer composite capable of uniform distribution over long distances and rapid utilization, and process for the production thereof

Abstract

The subject of the invention is a fertilizer composite which, in terms of application, has more favorable properties than the solutions available in the prior art. Accordingly, the subject of the invention is a fertilizer composite that can be uniformly spread over a distance of more than 20 meters, is gentle on the spreader, and is rapidly utilizable in the soil, said fertilizer composite comprising: a) nitrogen derived from ammonium nitrate in an amount of about 10-30% by weight; b) calcium derived from calcium oxide in an amount of about 5-15%by weight; c) a sulfur source calculated as sulfur trioxide equivalent in an amount of about 5-15% by weight, or a magnesium source selected from calcium-magnesium oxide or magnesium oxide in an amount of about 5-15% by weight; and d) conventional additives used in fertilizer production in an amount required to reach 100% by weight, preferably ammonium sulfate in an amount of about 0.3% by weight, wherein 90-100% of the fertilizer composite has a particle size of 0.5-10 mm and the particles are essentially spherical. The average strength of the particles is about 63.74 N for fertilizers containing magnesium and about 72.83 N for fertilizers containing sulfur. The invention further relates to a method for producing the fertilizer composite according to the invention.

Description

[0001] HIGH-STRENGTH FERTILIZER COMPOSITE CAPABLE OF UNIFORM DISTRIBUTION OVER LONG DISTANCES AND RAPID UTILIZATION, AND PROCESS FOR THE PRODUCTION THEREOF

[0002] The subject of the invention is a fertilizer composite which, in terms of application, has more favorable properties than the solutions available in the prior art. Accordingly, the subject of the invention is a fertilizer composite that can be uniformly spread over a distance of more than 20 meters, is gentle on the spreader, and is rapidly utilizable in the soil, said fertilizer composite comprising: a) nitrogen derived from ammonium nitrate in an amount of about 10-30% by weight; b) calcium derived from calcium oxide in an amount of about 5-15%by weight; c) a sulfur source calculated as sulfur trioxide equivalent in an amount of about 5-15% by weight, or a magnesium source selected from calcium-magnesium oxide or magnesium oxide in an amount of about 5-15% by weight; and d) conventional additives used in fertilizer production in an amount required to reach 100% by weight, preferably ammonium sulfate in an amount of about 0.3% by weight, wherein 90-100% of the fertilizer composite has a particle size of 0.5-10 mm and the particles are essentially spherical. The average strength of the particles is about 63.74 N for fertilizers containing magnesium and about 72.83 N for fertilizers containing sulfur. The invention further relates to a method for producing the fertilizer composite according to the invention.

[0003] INTRODUCTION OF THE STATE OF THE ART

[0004] Agriculture is a critical sectortbat provides livelihoods for billions of people worldwide and is essential for ensuring food security. The efficiency and productivity of agricultural practices depend heavily on the use of fertilizers, which supply essential nutrients for plants. Fertilizers typically consist of various chemical compounds that provide nutrients such as nitrogen, phosphorus, and potassium, which are vital for plant growth. However, the effectiveness of fertilizers may be influenced by their chemical composition, particle size, and shape, which affect the rate at which nutrients are released and absorbed by plants.

[0005] In recent years, there has been a growing demand for more efficient and environmentally friendly fertilizers that can enhance crop y ields while minimizing negative environmental impacts. Conventional fertilizers often face challenges such as nutrient leaching, volatilization, and uneven distribution in the soil, which lead to suboptimal nutrient uptake by plants. As a result, there is a need for innovative fertilizer formulations that provide a balanced nutrient supply, improve nutrient use efficiency, and reduce the environmental footprint. The development of fertilizer composites with specific chemical compositions and physical properties, as well as the adoption of more environmentally friendly production methods, represents a promising approach to addressing these challenges and meeting the evolving needs of modem agriculture.

[0006] European patent EP1851182B1 relates to an ammonium nitrate -containing fertilizer granule comprising a core containing ammonium nitrate and a coating layer containing calcium sulfate and ammonium nitrate. Such fertilizer granules are preferably prepared by contacting the core with an aqueous ammonium nitrate solution and solid calcium sulfate particles, either in the form of slurry or separately. The calcium sulfate may be anhydrite, hemihydrate, or dihydrate (gypsum) formed in situ. Canadian patent No. CA690399A relates to fertilizers containing ammonium nitrate, urea, and inert filler, wherein the percentage ratio of the components falls within the range of 60:(35-5):(5-35) to 80:15:5, and wherein the total weight of urea and the inert filler is at least 20%. The inert filler may be limestone, gypsum, or anhydrite.

[0007] British patent GB571080A discloses a fertilizer composition comprising 97 parts of a fertilizer marketed under the name " Nitro-Chalk" (i.e., ammonium nitrate mixed with calcium carbonate) and 3 parts of calcined gypsum (" Plaster of Paris", i.e., CaSCh O. SIB O) for the purpose of improving storage stability.

[0008] The invention described in U. S. patent US10450239B2 relates to fertilizer granules and a method for their preparation. The fertilizer granules are spherical in shape, have a density greater than 1.94 g / cm3, and a porosity of less than 3%, thus ensuring efficient nutrient release. The granules may contain various types of fertilizers, including single- and multi-component, organic, phosphate, and potassium fertilizers. Granules formed from fertilizer powders consisting of particles of different sizes are further provided with one or more coating layers, which may include waxes, oils, stearic acid, or polymers, thereby improving efficiency and stability.

[0009] International patent application WO2024105561A1 discloses a fertilizer comprising calcium ions, nitrogen in the form of ammonium ions and nitrate ions, sulfur present as sulfate ions, and further comprising silicates. Industrial process waste products are used as raw materials for producing the fertilizer. The resulting fertilizer may be in gel or granule form. In the fertilizer according to the invention, slow nutrient uptake is promoted by the fact that at least a portion of the ammonium sulfate and / or calcium nitrate is encapsulated within ammonium silicate.

[0010] BRIEF DESCRIPTION OF THE FIGURES

[0011] Figure 1. Schematic flow chart of the production technology for fertilizers containing sulfur sources.

[0012] Figure 2. Schematic flow chart of the manufacturing technology for fertilizers containing magnesium sources.

[0013] TECHNICAL PROBLEM TO BE SOLVED BY THE INVENTION

[0014] There is a need for a fertilizer granulate comprising granules having an average particle strength, as determined using a TBH force gauge, of about 72-73 N in the case of a fertilizer containing a sulfur source, and about 63-64 N in the case of a fertilizer containing a magnesium source, whereby the granules exhibit high resistance to physical stresses and do not fracture under their own weight. The physical properties of the fertilizer granulate render it suitable for uniform application using both conventional and pneumatic fertilizer spreader, and further enable its application through aerial fertilization methods, including aircraft- or drone-based spreading. There is a need for a fertilizer that can be applied over long distances with an excellent spreading pattern, while its granules cause minimal abrasion to the metallic components of the spreader. A further objective is to provide a fertilizer composite that is readily utilizable in the soil. Finally, it is desirable to provide an environmentally friendly process to produce the fertilizer composite according to the invention. RECOGNITION FORMING THE BASIS OF THE INVENTION

[0015] It has been recognized that the above -identified technical problems can be solved if

[0016] a) a fertilizer composite is prepared in which 90-100% of the fertilizer composite has a particle size of 0.5-10 mm and the particles are essentially spherical in shape;

[0017] b) a production process is applied in which the water vapor generated during the production of ammonium nitrate and the ammonium nitrate solution are separated in a vacuum separator, the vapor is purified in the vacuum separator from nitric acid vapors and ammonium nitrate droplets contained therein, and the vapors leaving the evaporating vacuum separator are condensed;

[0018] c) the desired utilization can be achieved by grinding the calcium sulfate used in the production of the fertilizer composite to a particle size of about 40 pm.

[0019] BRIEF DESCRIPTION OF THE INVENTION

[0020] 1. A fertilizer composite that can be spread evenly over a distance of more than 20 meters, is gentle on the spreader, and is rapidly utilized by the soil, containing:

[0021] a) about 10-30% by weight of nitrogen derived from ammonium nitrate;

[0022] b) about 5-15% by weight of calcium derived from calcium oxide;

[0023] c) about 5-15% by weight of sulfur calculated as sulfur trioxide equivalent, or about 5-15% by weight of a magnesium source selected from the group consisting of calcium magnesium oxide and magnesium oxide; and

[0024] d) additives customary in fertilizer production in an amount required to reach 100% by weight, preferably about 0.3% by weight of ammonium sulfate, characterized in that 90-100% of the fertilizer composite has a particle size of 0.5-10 mm and the particles are essentially spherical in shape, having an average particle strength of 60-75 N, preferably 63-64 N in the case of fertilizer containing a magnesium source, for example 63.74 N, and in the case of fertilizers containing a sulfur source, 72-73 N, for example 72.83 N.

[0025] 2. The fertilizer composite according to claim 1, comprising about 10% by weight of nitrogen derived from ammonium nitrate, about 12% by weight of ammoniacal nitrogen, about 9% by weight of calcium derived from calcium oxide, about 12% by weight of sullur source calculated as sulfur trioxide equivalent, and a surfactant and / or additives customary in fertilizer production in an amount required to reach 100% by weight, preferably about 0.3% by weight ammonium sulfate.

[0026] 3. The fertilizer composite according to claim 1, comprising about 16% by weight of nitrogen derived from ammonium nitrate, about 16% by weight of calcium derived from calcium oxide, about 12% by weight of magnesium oxide, and a surfactant and / or additives customary in fertilizer production in an amount required to reach 100% by weight, preferably containing about 0.3% by weight of ammonium sulfate.

[0027] 4. Fertilizer composite according to claims 1-4, characterized in that 95% of the fertilizer composite has a particle size of 0.8-6.3 mm. 5. A method for the environmentally friendly production of the fertilizer composite according to claims 1-5, comprising the following steps:

[0028] a) producing an ammonium nitrate solution in an ammonium nitrate neutralization tank by a method known per se according to the following reaction equation: NH3(gas) + HNO3(aqueous solution) NH4NO3(aqueous solution), wherein during the process the solution is circulated, thereby removing the reaction heat generated;

[0029] b) concentrating the ammonium nitrate solution in one or more steps by removing water vapor generated by the reaction heat, thereby obtaining an ammonium nitrate melt, and, prior to the final concentration step, optionally adding an ammonium sulfate additive generated in sit,

[0030] c) grinding an inorganic material selected from the group consisting of calcium sulfate, calcium magnesium oxide, and magnesium oxide to a desired particle size; then

[0031] d) granulating the ammonium nitrate melt obtained in step b), the ground inorganic material, and optionally other additives customary in fertilizer production, and, if required, shaping the granules into an essentially spherical form; e) optionally separating the particles according to particle size, as required,

[0032] characterized in that

[0033] in step b) the water vapor and the ammonium nitrate solution are separated in a vacuum separator, in the vacuum separator, the vapor is purified in the vacuum separator from nitric acid vapors and ammonium nitrate droplets contained therein, the vapors leaving the evaporating vacuum separator are condensed, thereby producing a clean process condensate, the heat content of the expanded process vapors is utilized for preheating the ammonia and nitric acid fed to the reactor, and the clean process condensate is recycled in the production process.

[0034] 6. The process according to claim 5, characterized in that the calcium sulfate used in step c) is ground to a particle size of about 40 pm.

[0035] DETAILED DESCRIPTION OF THE INVENTION

[0036] The invention relates to a fertilizer composite with a special chemical composition and physical properties that enable advantageous agricultural application.

[0037] Split nitrogen fertilization adjusted to the growth rate of plants allows not only an increase in yield quantity and quality, but also improved nitrogen use efficiency.

[0038] The fertilizer composite according to the invention is characterized by a composition which is uniformly distributable over a distance exceeding 20 meters, is non-detrimental to spreader, and ensures rapid nutrient availability in soil. Said composite comprises: 10-30% by weight of nitrogen derived from ammonium nitrate; 5-15% by weight of calcium derived from calcium oxide; 5-15% by weight of sulfur source calculated as sulfur trioxide equivalent, or about 5-15% by weight of a magnesium source selected from the group consisting of calcium magnesium oxide and magnesium oxide. This composition shall be formulated to ensure adequate nutrient distribution and nutrient supply to plants. The particle size of the fertilizer composite is predominantly in the range of 0.5-10 mm, which may promote uniform distribution and absorption in the soil. The spherical shape of the composite may facilitate ease of application and enhance uniform spreading.

[0039] The fertilizer composite according to the invention, which can be evenly spread over distances exceeding 20 meters, is gentle on spreader and allows rapid utilization in the soil, comprises about 12% by weight of nitrogen derived from ammonium nitrate, about 12% by weight of nitrogen derived from ammonia, about 9% by weight of calcium derived from calcium oxide, about 12% by weight sulfur source calculated as sulfur trioxide equivalent, and a quantity of surfactant and / or additives customary in fertilizer production required to reach 100% by weight, preferably containing 0.3% by weight of ammonium sulfate.

[0040] The fertilizer composite according to the invention, which can be evenly spread over distances exceeding 20 meters, is gentle on spreader and allows rapid utilization in the soil, comprises about 16% by weight nitrogen derived from ammonium nitrate, about 16% by weight calcium derived from calcium oxide, about 12% by weight magnesium source derived from magnesium oxide, and a quantity of surfactant and / or additives customary in fertilizer production required to reach 100% by weight, preferably containing 0.3% by weight ammonium sulfate.

[0041] The fertilizer composite according to the invention, which can be evenly spread over distances exceeding 20 meters, is gentle on spreader and allows rapid utilization in the soil, has particles of which 90-100% have a size between 2-8 mm and are spherical in shape; preferably, 95% of the particles have a size between 0.8-6.3 mm.

[0042] In one embodiment of the fertilizer composite according to the invention, which can be evenly spread over distances exceeding 20 meters, is gentle on spreader and allows rapid utilization in the soil, the fertilizer containing a sulfur source has an average granule strength of 72.83 N.

[0043] In one embodiment of the fertilizer composite according to the invention, which can be evenly spread over distances exceeding 20 meters, is gentle on spreader and allows rapid utilization in the soil, the fertilizer containing a magnesium source has an average granule strength of 63.74 N.

[0044] According to one embodiment of a process for producing a fertilizer composite according to the invention that can be evenly spread over a distance of more than 20 meters, is gentle on the spreader, and is rapidly utilizable in the soil, in step (a) an ammonium nitrate solution is prepared in an ammonium nitrate neutralization tank by a method known per se, according to the following reaction equation: NH3(gas) + HNCh (aqueous solution) NH4NO3 (aqueous solution), wherein the solution is circulated during the process to dissipate the resulting heat of reaction. In step b), the ammonium nitrate solution is concentrated in one or more steps by removing the water vapor generated by the heat of reaction to obtain an ammonium nitrate melt, and prior to the final concentration step, optionally, an ammonium sulfate additive generated in situ is added. Subsequently, in step (c), an inorganic material selected from the group consisting of calcium sulfate, calcium magnesium oxide, and magnesium oxide is ground to the desired particle size. Then, in step (d), the ammonium nitrate melt obtained in step (b), the ground inorganic material, and optionally other additives customary in fertilizer production are granulated, and if required, the granules are shaped into a spherical form. Finally, in step (e), if necessary, the granules are classified according to particle size, characterized in that in step (b) the water vapor and the ammonium nitrate solution are separated in a vacuum separator, wherein the vapor is purified from nitric acid vapors and ammonium nitrate droplets, the vapors leaving the evaporation vacuum separator are condensed to produce a clean process condensate, and the heat content of the expanded process vapors is utilized for preheating the ammonia and nitric acid fed into the reactor, while the clean process condensate is recycled in the production process.

[0045] In one embodiment of the fertilizer composite according to the invention, which can be evenly spread over distances exceeding 20 meters, is gentle on spreader and allows rapid utilization in the soil, the calcium content present in addition to nitrogen improves soil structure (by increasing porosity and thereby enhancing water, heat, and air retention), increases soil fertility, and contributes to meeting the calcium demand of plants. By improving ionic balance, the uptake and utilization of other nutrients are also enhanced. The fertilizer composite according to the invention, which can be evenly spread over distances exceeding 20 meters, is gentle on spreader and allows rapid utilization in the soil, can be applied with an excellent spreading pattern over distances greater than 24 m.

[0046] The particles of the fertilizer composite according to the invention, which can be evenly spread over distances exceeding 20 meters, is gentle on spreader and allows rapid utilization in the soil, are spherical in shape. Its spherical particles cause minimal abrasion to the metal components of the machinery. Due to the larger, spherical particle shape, the application rate of the spreader can be adjusted with greater precision.

[0047] In one embodiment of the fertilizer composite according to the invention, which can be evenly spread over distances exceeding 20 meters, is gentle on spreader and allows rapid utilization in the soil, the sulfur content makes the fertilizer excellently suited for the fertilization of sulfur-deficient soils and sulfur-demanding crops (e.g., oilseed crops).

[0048] By applying the fertilizer according to the invention containing a sulfur source, sulfur can be replenished in the soil together with nitrogen. Depending on the dosage, it is suitable for remedying or preventing sulfur deficiency.

[0049] In the sulfuric fertilizer according to the invention, the finely ground sulfur compound ensures the rapid utilization of calcium and sulfur.

[0050] When using the fertilizer containing a sulfur source according to the invention, sulfur increases oil content, aids nitrogen incorporation, improves the overall health of the plant, its stress tolerance, stem strength, and quality parameters (baking value, protein content, digestibility, gluten content).

[0051] The granules of the fertilizer containing sulfur according to the invention are highly stable, with an average granule strength of 72.83 N. They do not crumble under their own weight. Their physical properties make them suitable for even distribution using conventional and pneumatic fertilizer spreaders, and even for aerial fertilization.

[0052] The fertilizer granules containing a magnesium source according to the invention are particularly recommended for acidic soils, as they are able to raise the pH of the soil thanks to their high natural lime content (576 kg / t) and contribute to meeting the calcium and magnesium requirements of plants.

[0053] The fertilizer granules containing a magnesium source according to the invention are resistant to physical impact thanks to their hard, solid particles. The particles have an average particle strength of 63.74 N. The finely ground dolomite contained in the granules ensures rapid utilization and a lasting effect.

[0054] The fertilizer granules containing a magnesium source according to the invention improve ion balance, thereby facilitating the uptake and utilization of other nutrients. They can nourish the plant and improve the chemical properties of acidic soil in a single step.

[0055] When applied in the appropriate dosage, the fertilizer granules containing a magnesium source according to the invention cover the calcium and magnesium requirements of 10 t / ha of com, 4 t / ha of sunflower, 4 t / ha of rapeseed, or 9 t / ha of wheat. It is an excellent solution for magnesium-demanding crops such as potatoes, sugarbeets, perennial legumes, com, rapeseed, cereals (oats), horticultural crops, and medicinal plants. The preferred embodiments of the invention are shown in Table 1. The table contains nitrogen calculated as nitrate equivalent, nitrogen calculated as ammonia equivalent, calcium calculated as calcium oxide equivalent, magnesium calculated as magnesium oxide equivalent, and sulfur calculated as sulfur trioxide equivalent.

[0056] Table 1. Preferred embodiments of the invention.

[0057] material composition sulfur-containing magnesium-containing (equivalent) fertilizer fertilizer

[0058] nitrate nitrogen 12% 7.95%

[0059] ammonia nitrogen 12% 7.95%

[0060] calcium oxide 9% 16.1%

[0061] magnesium oxide — 11.6%

[0062] sulfur trioxide 12%

[0063] EXAMPLES

[0064] Example 1: Production of a fertilizer containing a sulfur source

[0065] During the production of the fertilizer containing a sulfur source, ammonia (Nitrogenmuvek Zrt), nitric acid (Nitrogenmuvek Zrt.), anhydrous calcium sulfate (also known as anhydrite), ammonium sulfate additive, and a surface treatment agent were used as raw materials.

[0066] The large-scale production was carried out in a plant consisting of three units, see Figure 1. The function of plant unit I was the production of ammonium nitrate melt; plant unit II was responsible for the production of ground anhydrite; and finally, plant unit III was responsible for the production of the fertilizer containing a sulfur source.

[0067] 1.1. Technological description of plant unit I:

[0068] The chemical reaction serving as the basis of the technology is described by the following reaction equation: NH3(gas) + HNO3 (aqueous solution) — NH4NO3 (aqueous solution) + HR, where HR = -1345 kJ / kg The two raw materials for neutralization are ammonia gas and a 60% aqueous solution of nitric acid. The ammonia enters plant unit I directly in gaseous form. The main component of plant unit I is the neutralization circuit, consisting of a neutralization reactor, a vacuum separator, and a circulation pump. The gaseous ammonia enters the neutralization reactor, to which nitric acid is added at a controlled rate in the appropriate ratio. The reaction is exothermic; the released heat is utilized to evaporate a portion of the water content. The vapor and the solution are separated in a separator. Due to the high heat release, the neutralization itself takes place in circulated ammonium nitrate solution. The technology is designed such that boiling can only occur in the separator. The product stream of the formed ammonium nitrate solution leaves the neutralization circuit via an overflow. In the vacuum separator, the vapor is purified from the nitric acid vapors and ammonium nitrate droplets contained therein. Washing is performed on special trays by spraying with pure technological condensate. The heat content of the expanded technological vapors is utilized during the preheating of the ammonia and nitric acid fed into the reactor, and the excess is then condensed. The so-called "pure technological condensate" originating from the preheaters and the steam condenser is utilized at various points in the process. The ammonium nitrate solution flows by gravity into the neutralizer tank, where ammonia is added (pH adjustment), then passes through the ammonium sulfate neutralizing reactor (serving for the in situ production of ammonium sulfate) and, following the addition of sulfuric acid, enters the ammonium nitrate solution tank. This functions as the feed tank for the evaporation unit. After pH adjustment, the resulting ammonium nitrate solution enters the autocirculation evaporator, which consists of a boiler and a vacuum separator. Further concentration of the solution takes place in the evaporator.

[0069] As part of the environmental load reduction activities, the expanded technological vapors in the neutralization loop are purified in the vacuum separator from the nitric acid vapors and ammonium nitrate droplets; washing is performed on special trays by spraying with pure technological condensate. The heat content of the expanded technological vapors is utilized during the preheating of the ammonia and nitric acid fed into the reactor, and the excess is then condensed. The pure technological condensate from the preheaters and the steam condenser is utilized at various points in the process, and a significant portion is discharged as effluent due to its extremely low pollutant content. The vapors leaving the evaporation vacuum separator are condensed, and the technological condensate is then utilized from the storage tank in various parts of the plant.

[0070] 1.2. Technological description of plant unit II:

[0071] The physical operation underlying the technology is the grinding of raw anhydrite. The raw anhydrite is transported from the truck to the storage bunker via a conveyor belt system. The grinding mill is fed from the bunker using a Redler-type conveyor. The anhydrite is crushed between the mill's grinding wheels and the grinding ring located on the side of the mill. From there, the ground material is transported to the dynamic classifier by air conveyor, mixed with air heated in a gas burner and partially recirculated. Here, the classifier blades select the oversized particles, which fall down the mill wall into the grinding chamber. The particles of the correct size enter the bag filter, where the hot air and anhydrite dust are separated. The hot air continues in two directions after the main fan. One part is released into the atmosphere through a silencer, while the other part is returned between the gas burner and the mill inlet. The separated anhydrite powder is transported by a conveyor screw to one of the powder storage bunkers. Two conveyor screws located under the bunkers feed the finished anhydrite powder into the collection screw, which transports it to the elevator. The end of the elevator is connected to a conveyor screw, which feeds the powder storage bunker of plant unit III. As part of our efforts to reduce our environmental impact, after passing through the bag filter of plant unit II, part of the hot air is released into the atmosphere through a silencer, while the other part is returned to the process for heat recovery.

[0072] 1.3. Technological description of plant unit III

[0073] The physical operation underlying the technology is the granulation of sulfur-containing fertilizer products. The granulated product is produced from ammonium nitrate melt and anhydrite powder generated in plant uection I, mixed in various proportions. The main technological device used for granulation is a twin-shaft granulator (pugmill), into which the ammonium nitrate melt, anhydrite powder and material flows recycled from the technology are fed. Particle formation takes place in the granulator, from where the material flow passes through a vibrating conveyor to the granulation / spherical drum. Here, the particles are shaped, and then the fertilizer is transferred to the drying drum, through which the particles pass to reach the appropriate moisture content. The basket filter at the end of the drying drum divides the product into two material flows. Particles smaller than 20 mm go directly to the elevator, while larger ones go to a pre-breaker and then to the elevator. The elevator feeds the product through a distributor to the screens, whose task is to separate particles that do not meet the specification from the material flow. According to the appropriate size, 95% of the particles are between 0.8 and 6.3 mm in size. Particles outside this size range are transported via a cylindrical crusher to the so-called return belt and then reused in the granulator. The finished product belt transports the product with the correct particle size to the fluid cooler, where it is cooled to 30 °C with conditioned air. From the fluid cooler, the fertilizer is transported by conveyor belt to the surface treatment drum. The air used in the fluid cooler is pretreated in the air conditioning system. Here, part of the water content is precipitated by cooling the air, and the air is then reheated for further use. The air is cooled by evaporating liquid ammonia, and the resulting ammonia gas is utilized in Plant I. The air leaving the fluid cooler is used as drying air in the drying drum. The dust content of the process air leaving the cooling and drying process is separated in cyclones. As part of our efforts to reduce our environmental impact, multicyclones are used in plant III to separate dust from the process air, and bag filters are used to clean the air leaving the extraction devices.

[0074] Example 2: Use of fertilizer containing sulfur

[0075] Due to its sulfur content, we used it to fertilize sulfur-deficient soils and sulfur-demanding crops (e.g., oil plants). It can be used to supplement nitrogen and sulfur in a single step. Anhydrite ground to a fineness of 40 pm ensured rapid utilization of calcium and sulfur. The larger particle size and spherical particle shape allowed for more precise adjustment of the seeder's spread rate.

[0076] In all horticultural and arable crops, we applied it as a base, starter, and top-dressing fertilizer at a dose of 100-800 kg / ha, in accordance with plant requirements, expert advice, and applicable legal regulations.

[0077] Example 3: Production of fertilizer containing magnesium

[0078] In the production of fertilizer containing magnesium, we used ammonia (Nitrogenmuvek Zrt), nitric acid (Nitrogenmuvek Zrt.), dolomite, sulfuric acid, ammonium sulfate additive, and surface treatment agent as raw materials.

[0079] Larger quantities were produced in a plant consisting of three units, see Figure 2. The task of plant unit I was to produce molten ammonium nitrate, the task of plant unit II was to produce anhydrite powder, and finally, the task of plant unit III was to produce fertilizer containing magnesium.

[0080] 3.1. Technological description of plant unit I:

[0081] The chemical reaction underlying the technology can be described by the following reaction equation: NH3(gas) + HNO3 (aqueous solution) — NH4NO3 (aqueous) + HR, where HR = -1345kJ / kg

[0082] The two basic materials used in neutralization are ammonia gas and a 60% aqueous solution of nitric acid. The ammonia enters plant unit I directly in gaseous form. The main part of plant unit I is the neutralization circuit, which consists of a neutralization reactor, a vacuum separator, and a circulation pump. The ammonia gas enters the neutralization reactor, where nitric acid is added in a controlled manner at the appropriate ratio. The reaction is exothermic, and the heat released is used to evaporate part of the water content. The vapor and the solution are separated in the separator. Due to the high heat release, the neutralization itself takes place in a circulated ammonium nitrate solution. The technology is designed so that boiling can only occur in the separator. The product stream of the ammonium nitrate solution formed leaves the neutralization circuit through an overflow. In the vacuum separator, the vapor is cleaned of nitric acid vapors and ammonium nitrate droplets. Washing takes place on special trays, sprinkled with clean process condensate. The heat content of the expanded process vapors is used to preheat the ammonia and nitric acid fed into the reactor, and the excess is condensed. The so-called clean process condensate from the preheaters and the steam condenser is used at various points in the process. The ammonium nitrate solution flows by gravity into the neutralization tank, where ammonia is added (pH adjustment), then passes through the ammonium sulfate neutralization reactor (which is used for the in situ production of ammonium sulfate) and then, after the addition of sulfuric acid, into the ammonium nitrate solution tank. This functions as the feed tank for the evaporator unit. After pH adjustment, the resulting ammonium nitrate solution enters the autocirculation evaporator, which consists of a boiling drum and a vacuum separator. Further concentration of the solution takes place in the evaporator.

[0083] In order to reduce the environmental impact, the expanded process vapors are cleaned of nitric acid vapors and ammonium nitrate droplets in a vacuum separator during the neutralization process, which is carried out on special trays using clean process condensate for washing. The heat content of the expanded process vapors is utilized during the preheating of the ammonia and nitric acid fed into the reactor, and the excess is then condensed. The so-called clean process condensate from the preheaters and the steam condenser is used at various points in the process, with a significant portion being discharged into wastewater due to its extremely low pollutant content. The vapors leaving the evaporator vacuum separator are condensed and then used in various parts of the plant from the process condensate tank.

[0084] 3.2. Technological description of plant unit II

[0085] The physical operation serving as the basis of the technology is the grinding of raw anhydrite. The raw anhydrite is transported from trucks via a conveyor belt system into the raw material storage bunker. The grinding mill is fed from the bunker using a Redler-type (drag chain) conveyor. The anhydrite is pulverized between the mill's impellers and the grinding ring located on the side of the mill. From here, the ground material is transported to the dynamic classifier by pneumatic means, using a mixture of air heated in a gas burner and partially recirculated air. In the classifier, the impeller blades separate the oversized particles, which fall back into the grinding chamber along the mill wall. Particles of the appropriate size proceed to the baghouse dust filter, where the hot air and the anhydrite powder are separated. After the main fan, the hot air proceeds in two directions. One part is discharged into the atmosphere through a silencer, while the other part is recirculated between the gas burner and the mill inlet. The separated anhydrite powder is delivered by a screw conveyor to one of the powder storage bunkers. Two screw conveyors located under each bunker feed the finished anhydrite powder into a collecting screw conveyor, which transports it further to the elevator. The end of the elevator is connected to a screw conveyor that feeds the powder storage bunker of plant unit III. As part of the environmental load reduction activities, after the baghouse dust filter of plant unit II, one part of the hot air is discharged into the atmosphere through a silencer, while the other part is recirculated into the technology for heat recovery purposes.

[0086] 3.3. Description of the technology used in plant unit III

[0087] The physical operation serving as the basis of the technology is the granulation of the sulfur-containing fertilizer product. The granulated product is produced by mixing the ammonium nitrate melt generated in plant unit I and the ground anhydrite from plant unit II in various proportions. The primary technological equipment for granulation is a twin-shaft granulator (pugmill), into which the ammonium nitrate melt, the ground anhydrite, and the material streams recycled from the process are fed. Granule formation occurs in the granulator, from where the material stream passes through a vibrating chute into the granulating / spherical drum. This is where the particles are shaped, after which the fertilizer is transferred to the drying drum, passing through which the granules reach the appropriate moisture content. A basket filter at the end of the drying drum splits the product into two material streams. Particles smaller than 20 mm go directly to the elevator, while larger ones pass through a pre-breaker before reaching the elevator. The elevator delivers the product via a distributor to the sieves, whose task is to separate off-specification particle sizes from the material stream. According to the appropriate sizing, 95% of the particles are between 0.8-6.3 mm. These out-of-spec particles are sent through a roller crusher onto the so-called return belt and are reused in the granulator. The product with the correct particle size is transported by the finished product belt to the fluid bed cooler, where it is cooled to 30 °C using conditioned air. From the fluid bed cooler, a conveyor belt carries the fertilizer to the surface treatment drum. The air used in the fluid bed cooler is pre-treated in an air conditioning system. Here, by cooling the air, a portion of the water content is condensed, and the air is then reheated for further use. The cooling of the air is achieved by the evaporation of liquid ammonia, and the resulting ammonia gas is utilized in plant unit I. The air leaving the fluid bed cooler is utilized as drying air in the drying drum. The dust content of the technological air leaving the cooling and drying processes is separated in cyclones. As part of the environmental load reduction activities in plant unit III, multi-cyclones are used to separate dust from the technological air, and a baghouse dust filter is used to purify the air leaving the equipment under suction.

[0088] Example 4: Application of a fertilizer containing a magnesium source

[0089] Thanks to its uniquely high and finely ground dolomite content, the fertilizer containing a magnesium source according to the invention was able to increase the soil pH rapidly and sustainably, contributing to meeting the calcium and magnesium requirements of the plants. Due to its large particle size, it can be applied with an excellent spread pattern even at distances exceeding 24 meters. The application of every single ton of the fertilizer containing a magnesium source is equivalent to a lime fertilization treatment.

[0090] In all horticultural and field crops, it was applied as a base, starter, and top-dressing fertilizer at a dosage of 200-1200 kg / ha, in accordance with plant requirements, expert advice, and current regulatory requirements.

[0091] Example 5: Determination of static particle strength for granulated fertilizers

[0092] Based on the standard MKLSZ-151:2023, the force required to crush a fertilizer particle of a given diameter was determined. The following equipment was used: an Erweka TBH 325 hardness tester, a printer, sieves with hole diameters of 4.00 mm, 3.35 mm, and 3.15 mm, tweezers, and abrush. During sample preparation, two fractions were sieved from the sample to be tested: a fraction between 4.0 and 3.15 mm, and a fraction between 3.35 and 3.15 mm. The first particle was placed between the two crushing jaws using tweezers, after which the device crushed the particle. During measurement, the crushed particles were swept into a plastic collector on the side of the device using a brush. The device continuously requests the pre-set number of samples. After crushing the designated number of particles, the device stops automatically. The measurement report includes the number of particles crushed, their diameter, indicates the minimum and maximum force values, and averages the crushing strength.

[0093] The average particle strength of the products was 72.83 N for the fertilizer containing a sulfur source and 63.74 N for the fertilizer containing a magnesium source. material composition sulfur-containing magnesium-containing

[0094] (equivalent) fertilizer fertilizer

[0095] nitrate nitrogen 12% 7.95%

[0096] ammonia nitrogen 12% 7.95%

[0097] calcium oxide 9% 16.1%

[0098] magnesium oxide — 11.6%

[0099] sulfur trioxide 12%

[0100] Embodiment Example 1: Process for the production of a granulated fertilizer containing sulfur, nitrate and ammonium nitrogen, as well as calcium oxide and sulfur trioxide equivalents, comprising the following steps:

[0101] First, an ammonium nitrate (AN) melt was formed by continuously feeding 600 g of a 60 w / w% aqueous nitric acid solution into a neutralization reactor, into which 105 g of ammonia gas (NH3) was introduced. Vapor separation was carried out in a vacuum separator, and the solution was concentrated in an auto-circulation evaporator until an AN melt with a dry matter content of 95-99 w / w% was formed. From the melt, 686 g of AN on a dry equivalent basis was carried forward into the subsequent part of the process.

[0102] Next, 325 g of commercially available, mined, anhydrous calcium sulfate (anhydrite, CaSO4) was ground in a mill to a particle size below 250 pm, with a fineness set at D99.9 < 200 pm 11 g of finely ground limestone flour (CaCO3, at D99.9 < 200 pm) was measured and added thereto.

[0103] 686 g of AN melt (94-96% dry matter) was continuously poured into a granulator (pugmill), and the 325 g of ground anhydrite was added. The mixture was homogenized in the granulator for 60 seconds at a mixing temperature of 100 °C. The material was shaped into spheres in a circulation system over a period of 1 minute. The spherical particles were fed into a drying drum; the temperature of the exiting product was slightly below 90 °C.

[0104] The following composition was obtained as the finished product: NO3-N 12.0 w / w%, NH4-N 12.0 w / w%, CaO 9.0 w / w%, SO312.0 w / w%, wherein the particle size distribution was >95% in the range of 0.8-6.3 mm. Particle strength: 72.78 N.

[0105] Embodiment Example 2: Process for the production of a granulated fertilizer containing magnesium, nitrate and ammonium nitrogen, as well as calcium oxide and magnesium oxide equivalents, comprising the following steps:

[0106] The 60 w / w% nitric acid and ammonia were neutralized and evaporated according to Embodiment Example 1; 454 g of AN on a dry equivalent basis was carried forward into the subsequent part of the process.

[0107] Next, 550 g of dolomite flour (CaMg(CO3)2) was ground to a particle size below 250 pm, with a fineness of D99.9 < 200 pm.

[0108] 550 g of ground dolomite and 450 g of ammonium nitrate were continuously poured into a granulator (pugmill). The mixture was homogenized in the granulator for 60 seconds at a mixing temperature of 100 °C; the viscosity of the mixture was maintained alongside the auto-adjustment of the water content. The material was shaped into spheres in a circulation system over a period of 1 minute. The spherical particles were fed into a drying drum; the temperature of the exiting product was slightly below 90 °C.

[0109] The final product had the following composition: NO3-N 7.95 w / w%, NH4-N 7.95 w / w%, CaO 16.1 w / w%, MgO 11.6 w / w%. Particle strength: 58.0 N. INDUSTRIAL APPLICABILITY

[0110] The fertilizer containing magnesium oxide according to the invention is an excellent solution for magnesium-demanding crops, such as potatoes, sugar beets, perennial legumes, com, rapeseed, cereals (oats), horticultural crops, and medicinal plants. It can nourish the plant and improve the pH of acidic soils in a single step. When applied at the appropriate dosage, it covers the calcium and magnesium requirements of 10 t / ha of com, 4 t / ha of sunflower, 4 t / ha of rapeseed, or 9 t / ha of wheat. The fertilizer containing sulfur trioxide according to the invention is excellently suited for the fertilization of sulfur-deficient soils and sulfur-demanding crops (e.g., oilseed crops). It allows for the simultaneous replenishment of nitrogen and sulfur in a single pass. Depending on the dosage, it is suitable for remedying or preventing sulfur deficiency. The finely ground sulfur compound ensures the rapid utilization of both calcium and sulfur. Sulfur increases oil content, facilitates nitrogen incorporation, and improves the overall health, stress tolerance, and stem strength of the plant, as well as its quality parameters (baking value, protein content, digestibility, and gluten content). Due to the high-strength particles, the granules do not crumble under their own weight. Their physical properties make them suitable for uniform distribution using conventional and pneumatic fertilizer spreaders, and even for aerial fertilization.

Claims

CLAIMS1. A fertilizer composite that can be spread evenly over a distance of more than 20 meters, is gentle on the spreader, and is rapidly utilized in the soil, comprising:a) about 10-30% by weight of nitrogen derived from ammonium nitrate;b) about 5-18% by weight of calcium derived from calcium oxide;c) about 5-15% by weight of a sulfur source calculated as sulfur trioxide equivalent, or about 5-15% by weight of a magnesium source selected from the group consisting of calcium magnesium oxide and magnesium oxide; and d) additives customary in fertilizer production in an amount required to reach 100% by weight, preferably comprising about 0.3% by weight of ammonium sulfate, characterized in that 90-100% of the fertilizer composite has a particle size of 0.5-10 mm, the particles are substantially spherical in shape, and their average particle strength is 50-75 N, preferably 58-63 N for the fertilizer containing a magnesium source, and 72-75 N for the fertilizer containing a sulfur source.

2. The fertilizer composite according to claim 1, comprising about 10% by weight of nitrogen derived from ammonium nitrate, about 12% by weight of ammonia nitrogen, about 9% by weight of calcium derived from calcium oxide, about 12% by weight of a sulfur source calculated as sulfur trioxide equivalent, and a surfactant and / or additives customary in fertilizer production in an amount required to reach 100% by weight, preferably comprising about 0.3% by weight of ammonium sulfate.

3. The fertilizer composite according to claim 1, comprising about 16% by weight of nitrogen derived from ammonium nitrate, about 16% by weight of calcium derived from calcium oxide, about 12% by weight of magnesium oxide, and a surfactant and / or additives customary in fertilizer production in an amount required to reach 100% by weight, preferably comprising about 0.3% by weight of ammonium sulfate.

4. The fertilizer composite according to claims 1 to 3, characterized in that 95% of the fertilizer composite has a particle size in the range of 0.8-6.3 mm.

5. A process for the environmentally friendly production of the fertilizer composite according to claims 1 to 4, comprising the following steps:a) producing an ammonium nitrate solution in an ammonium nitrate neutralizing tank by a process known per se according to the following reaction equation: NH3(gas) + HNO3(aqueous solution) NH4NO3(aqueous solution), wherein the solution is circulated during the process to dissipate the resulting heat of reaction;b) concentrating the ammonium nitrate solution in one or more steps by removing the water vapor generated by the heat of reaction to obtain an ammonium nitrate melt, and before the final step of concentration, optionally adding an in situ generated ammonium sulfate additive thereto;c) grinding an inorganic material selected from the group consisting of calcium sulfate, calcium magnesium oxide, and magnesium oxide to a desired particle size;d) granulating the ammonium nitrate melt obtained in step b), the ground inorganic material, and optionally other additives customary in fertilizer production, and optionally, as required, shaping the granules into a spherical form; e) optionally, as required, separating the particles by particle size;characterized in thatin step b), the water vapor and the ammonium nitrate solution are separated in a vacuum separator, the vapor is purified in the vacuum separator from the nitric acid vapors and ammonium nitrate droplets contained therein, the vapors leaving the evaporation vacuum separator are condensed to produce a pure technological condensate, the heat content of the expanded technological vapors is utilized during the preheating of the ammonia and nitric acid fed into the reactor, and the pure technological condensate is recycled within the production process.

6. The process according to claim 5, characterized in that the calcium sulfate used in step c) is ground to a particle size of about 40 pm.

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