A novel process of preparation of zinc fertilizer in granular form

Abstract

The present invention pertains to fertilizers, specifically a novel method for producing zinc fertilizer in granular form More precisely, it relates to an innovative process for preparing zinc sulphate fertilizer directly from concentrated zinc solution. This novel approach yields granules with optimal strength, excellent solubility, and uniform shape, size, and porosity.

Description

[0001] A NOVEL PROCESS OF PREPARATION OF ZINC FERTILIZER IN

[0002] GRANULAR FORM

[0003] FIELD OF THE INVENTION

[0004] The present invention is related to the fertilizers. The present invention is related to a novel process of preparation of zinc fertilizer in granular form. The present invention, more particularly, is related to a novel process of preparation of zinc sulphate monohydrate in granular form directly from concentrated zinc solution rather than making zinc sulphate powder first and then compacting it to make zinc sulphate granules. The process of the present invention provides granules of optimum strength, good dispersibility, uniform shape and size and porosity.

[0005] BACKGROUND OF THE INVENTION

[0006] All crops need 16 essential nutrients to give appropriate yield. Zinc has always been recognised as the “most essential” micronutrient worldwide. Zinc deficiency is the most common micronutrient deficiency, affecting more than 50% of the World's agricultural soils.

[0007] Zinc Fertilizers are available in the market in various forms like Zinc Sulphate Heptahydrate, Zinc Sulphate Monohydrate, Zinc Oxide, Zinc EDTA etc. However, there is a fundamental problem with those fertilizers as they are all in powder form and cannot be distributed evenly in the field. Generally, these powder form Zinc fertilizers are coated over other NPK Fertilizers like Urea & DAP and then applied in the field. Zinc sulphate is a common product in the agricultural industry, especially when it comes to countering the various levels of zinc deficiencies in many types of plants, which can lead to poor plant development and reduced productivity.

[0008] The main reasons behind the use of zinc sulphate by the agricultural industry include increased plant growth and development, countering the effects of cool soil temperatures, improving soil fertility, and countering the effects of excess phosphorus fertilizers. While there are some Zinc Sulphate fertilizers in granular form available in the market, they are neither cost-effective nor uniform in size. They also lack good strength, therefore rendering them useless for application in the field via Mechanical Spreaders. These granules tend to break during transportation as they have low strength.

[0009] Therefore, there is a need to develop a composition of Zinc Fertilizer which can be used as easily as other NPK Fertilizers like Urea & DAP. Also, there is a need to develop a far more efficient fertilizer which can be broadcasted by hand or by machines or which can be sown directly with the seed via Mechanical Spreader. The composition must exhibit good dispersion, porosity, strength and coating capabilities to ensure uniform distribution throughout the field.

[0010] Zinc Sulphate Monohydrate Granules offer a clear advantage over the powder form by simplifying farm application. They also help reduce health-related issues faced by farmers during the application of powder fertilizers, as granules eliminate dust and prevent fertilizer from blowing back on them. Additionally, the use of granules ensures even distribution of the fertilizer in the field, giving the farmer more control. However, if the granules are not robust enough for use in a mechanical spreader, the farmer will face the same challenges as with the powder form.

[0011] In this light, it is important to look at the traditional method of creating Zinc Fertilizer Granules, the traditional method of preparation of zinc sulphate is an energy-intensive process wherein a lot of power is consumed in drying the water of the concentrated zinc solution, the traditional method is as follows: a) mixing zinc ash with sulphuric acid to make concentrated zinc solution via a reaction process; b) passing concentrated zinc solution through a filter press to screen impurities; c) feeding clear concentrated zinc solution to a spray dryer for drying the water and making zinc sulphate monohydrate powder; d) granulating the powder in a pan / disc granulator or roll compactor into granules; e) drying the granules by using, a pan granulator or drum drying process with heat from a hot air generator.

[0012] Spray drying is the process in which liquid is transformed into dried particles by spraying the feed into a hot drying medium. Even though spray drying is widely used in industries, it is still having some disadvantages like variations in particle shape and size distribution and high energy consumption due to heating of the air stream and atomization of the feed during spray drying.

[0013] Disc granulator is one of the main equipment for granulating compound fertilizer, organic fertilizer and organic-inorganic fertilizer. However, disc granulators have disadvantage of limited ability to control the size and shape of the granules. Disc Granulators also cannot ensure optimum granule strength, dispersibility, porosity and coating capabilities. Any compaction machine whether Disc Granulators or Roll Compacters don’t give the desired granule strength suitable to all field applications.

[0014] In the traditional process detailed above, there is high energy consumption due to the use of techniques such as spray drying and disc granulation. The traditional method involves a two-step process for creating granules: Step 1 - Producing Zinc Sulphate Monohydrate 33% powder; Step 2 - Compacting the powder to form granules. This method consumes a significant amount of energy and power, as it is used twice — first in powder production, and then again for granule formation. Hence, there is a need to develop a process wherein granules of uniform size with optimum strength, dispersibility, porosity and coating capabilities can be developed devoid of high energy consumption. Also, in the traditional process the concentrated zinc solution has to be first converted into a powder and then it is granulated, inventor of the present invention aims to skip this process and developed the technology by which one can manufacture the granules directly from concentrated zinc solution thereby avoiding the process of creating Zinc sulphate monohydrate powder altogether.

[0015] The inventor of the present invention has developed a novel process of preparation of a micronutrient fertilizer comprising of an effective amount of Zinc in granular form, from concentrated zinc solution which will overcome the disadvantages of traditional process. So far, it has been exploited to achieve the following objective.

[0016] OBJECTIVE OF THE INVENTION

[0017] The main objective of the invention is to provide a novel process of preparation of zinc fertilizer in granular form.

[0018] The other main objective of the invention is to provide a novel process of preparation of zinc fertilizer in granular form without making zinc sulphate monohydrate powder.

[0019] Another objective of the invention is to provide a novel process of preparation of zinc fertilizer in granular form directly from concentrated zinc solution.

[0020] Another objective of the present invention is to provide a novel process of preparation of zinc fertilizer in granular form with drying system which can provide free-flowing granules of uniform size.

[0021] Another objective of the invention is to provide a novel process of preparation of zinc fertilizer in granular form which is easy, fuel efficient, and energy efficient. Yet another objective of the invention is to provide a novel process of preparation of zinc fertilizer in granular form which provides granules of optimum strength to ensure a long period of transportation of the product worldwide.

[0022] One more objective of the invention is to provide a novel process of preparation of zinc fertilizer in granular form which provides uniform shape, and size.

[0023] One more objective of the invention is to provide a novel process of preparation of zinc fertilizer in granular form which provides granules which have coating capability and are porous enough to absorb other micronutrients.

[0024] One more objective of the present invention is to provide a novel process of preparation of zinc fertilizer in granular form which provides granules with 100% water solubility.

[0025] SUMMARY OF THE INVENTION

[0026] The main aspect of the present invention is to provide a novel process of preparation of zinc fertilizer, more particularly zinc sulphate monohydrate in granular form.

[0027] The other main aspect of the present invention is to provide a novel process of preparation of zinc fertilizer in granular form which comprises: a) mixing zinc ash with sulphuric acid solution to make concentrated zinc solution via a reaction process in a reactor with an agitator; b) passing concentrated zinc solution obtained in step (a) through a filter press to screen for impurities in the filtration system; c) feeding filtered concentrated zinc solution of step (b) to fluidized bed dryer with nozzle spray system; d) preparing the bed of zinc sulphate granules in a fluidized bed dryer for coating & drying; e) blowing the hot air at high pressure via a hot air generator to suspend the zinc sulphate granules in the air; f) spraying the concentrated zinc solution of step (c) from the nozzle system onto the zinc sulphate granules of step (e) for coating; g) passing the coated granules for sieving in a rotary shifter to get desired-sized granules by separating the oversized and undersized granules and feeding them back into the process; h) storing final zinc fertilizer granules and fine powder, separately in a suitable container for packaging.

[0028] The other aspect of the present invention is to provide zinc sulphate monohydrate granules which are free-flowing, have high strength, 100% water solubility, and are prepared by a process which eliminates manufacturing of zinc sulphate monohydrate powder thereby using less fuel and power.

[0029] DESCRIPTION OF THE INVENTION

[0030] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention: in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.

[0031] The wording herein below is implied in the common meaning of the definitions and statements as known to the person skilled in the art.

[0032] As stated in the present invention herein, the singular forms “a,” “an” and “the” specifically also encompass the plural forms of the terms to which they refer, unless the content clearly dictates otherwise. The term “about” is used herein to means approximately, in the region of, roughly, or around. As stated herein, that it follows in a transitional phrase or in the body of a claim, the terms “comprise(s)” and “comprising” are to be interpreted as having an open ended meaning. That is, the terms are to be interpreted synonymously with the phrases “having at least” or “including at least”. When used in the context of a process, the term “comprising” means that the process includes at least the recited steps, but may include additional steps. When used in the context of a composition, the term “comprising” means that the composition includes at least the recited features or components, but may also include additional features or components.

[0033] The present invention overcomes the aforesaid drawbacks of the traditional method, and other objects, features and advantages of the present invention will now be described in greater detail. Also, the following description includes various specific details and are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that: without departing from the scope and spirit of the present disclosure and its various embodiments there may be any number of changes and modifications described herein.

[0034] As used herein words “Zinc Fertilizer” or “Zinc Fertilizer Granules” or “zinc granules” refer to zinc sulphate monohydrate and these all can be used interchangeably

[0035] The main embodiment of the present invention is to provide a novel process of preparation of zinc fertilizer in granular form.

[0036] As per another main embodiment of the present invention, a novel process of preparation of zinc fertilizer in granular form which comprises of following steps: a) mixing zinc ash with sulphuric acid solution to make concentrated zinc solution via a reaction process in a reactor with an agitator; b) passing concentrated zinc solution obtained in step (a) through a filter press to screen for impurities in the filtration system; c) feeding filtered concentrated zinc solution of step (b) to fluidized bed dryer with nozzle spray system; d) preparing the bed of zinc sulphate granules in a fluidized bed dryer for coating & drying; e) blowing the hot air at high pressure via a hot air generator to suspend the zinc sulphate granules in the air; f) spraying the concentrated zinc solution of step (c) from the nozzle system onto the zinc sulphate granules of step (e) for coating; g) passing the coated granules for sieving in a rotary shifter to get desired-sized granules by separating the oversized and undersized granules and feeding them back into the process; h) storing final zinc fertilizer granules and fine powder, separately in a suitable container for packaging.

[0037] As per the preferred embodiment of the present invention, the zinc fertilizer is zinc sulphate monohydrate.

[0038] As per one embodiment of the present invention, the zinc ash is used in the range of 40-65% w / w.

[0039] As per one embodiment of the present invention, the zinc ash is of 50-70% purity.

[0040] As per one embodiment of the present invention, the sulphuric acid solution is prepared using 20-40% w / w sulphuric acid in water.

[0041] As per one embodiment of the present invention, the sulphuric acid used is 98% purity.

[0042] As per one embodiment of the present invention, the concentrated zinc solution is transferred to the filtration system after achieving gravity of 1.40-1.70 gm / cc and 2-4 pH. As per one embodiment of the present invention, the novel process provides for manufacturing zinc fertilizer by spraying a concentrated zinc solution on a bed of zinc sulphate monohydrate granules while hot air in being fed from below the bed of granules.

[0043] As per one embodiment of the present invention, the zinc sulphate granules are filled in the FBD to make a bed of 400 - 700 Kg.

[0044] As per one embodiment of the present invention, the novel process provides granules of different sizes from the fluidized bed dryer which are separated into three parts: oversized, undersized and required-sized granules.

[0045] As per one embodiment of the present invention, the coated granules are shifted from a fluidized bed dryer to a rotary shifter for crushing the oversized granules and sent back again to the fluidized bed dryer and undersized granules are directly sent back to the fluidized bed dryer.

[0046] As per one embodiment of the present invention, the granules of desired size are obtained by using the sieves of different sizes in the process i.e. l-2mm, 2-3mm, 2- 4mm, 3-4mm, 3-5mm, 4-5mm, 5-6mm, 4-7mm, 6-8 mm, and 8-10 mm.

[0047] As per one embodiment of the present invention, the temperature of the fluidized bed dryer is 120-160°C.

[0048] As per one embodiment of the present invention, the coal used to achieve the desired temperature of hot air is in the range of 4400-6000 Kcal / Kg.

[0049] As per one embodiment of the present invention, the zinc sulphate monohydrate is directly prepared using concentrated zinc solution without converting the solution into powder first. As per one embodiment of the present invention, the zinc sulphate monohydrate is a micronutrient, used in fertilizers, animal feed, paints etc.

[0050] As per one embodiment of the present invention, the zinc fertilizer comprising of an effective amount of Zinc, wherein the Zinc sulphate monohydrate can be in the range of 15-36% (w / w) with or without a binding agent or dispersing agent in granular form.

[0051] As per preferred embodiment of the present of the invention, the zinc sulphate monohydrate is free of binder, additives, resins and dispersing agents.

[0052] As per one embodiment of the present invention, zinc sulphate monohydrate granules are of particle size 1 mm to 10 mm.

[0053] As per one embodiment of the present invention, the novel process is fuel efficient and saves 5-20% fuel / hour.

[0054] As per one embodiment of the present invention, the novel process is energy efficient and saves energy by 15-32% power.

[0055] As per one embodiment of the present invention, a novel process of preparation of zinc fertilizer in granular form comprises of following steps: a) mixing zinc ash with sulphuric acid solution to make concentrated zinc solution via a reaction process in a reactor with an agitator; b) passing concentrated zinc solution obtained in step (a) through a filter press to screen for impurities in the filtration system; c) feeding filtered concentrated zinc solution of step (b) to fluidized bed dryer with nozzle spray system; d) preparing the bed of zinc sulphate granules in a fluidized bed dryer for coating & drying; e) blowing the hot air at high pressure via a hot air generator to suspend the zinc sulphate granules in the air; f) spraying the concentrated zinc solution of step (c) from the nozzle system onto the zinc sulphate granules of step (e) for coating; g) passing the coated granules for sieving in a rotary shifter to get desired-sized granules by separating the oversized and undersized granules and feeding them back into the process; h) storing final zinc fertilizer granules and fine powder, separately in a suitable container for packaging, wherein the process involves the preparation of the zinc sulphate fertilizer directly using concentrated zinc solution without converting the solution into powder first and the granules have lower dust levels.

[0056] As per one embodiment of the present invention, the novel process provides granules of uniform shape, uniform size, dispersibility, and porosity.

[0057] As per on embodiment of the present invention, the novel process provides granules having lower dust levels compared to compaction granules.

[0058] As per on embodiment of the present invention, the novel process provides granules possess 100-300% higher hardness, making them highly durable and resistant to breakage during mixing processes, whether on the farm or in a factory. This allows them to be seamlessly blended with other fertilizers using mechanical spreaders without compromising their integrity, ensuring reliable performance in multinutrient fertilizer formulations.

[0059] As per one embodiment of the present invention, the novel process provides granules with improved solubility, with 100% solubility enabling complete dissolution during use. As per one embodiment of the present invention, the novel process provides granules with enhanced mixing potential.

[0060] As per one embodiment of the present invention, the novel process provides granules with coating capabilities, the process can be used to apply coatings to granules for various purposes, such as the controlled release of nutrients or protecting sensitive ingredients from moisture or light.

[0061] As per one embodiment of the present invention, the novel process provides granules which can be fortified by l%-3% coating due to its porosity with other micronutrients including but not limited to Boron, Molybdenum, Copper, and Manganese.

[0062] The following examples, which include preferred embodiments, will serve to illustrate the practice of this invention, it being understood that the particulars shown are by way of example and for illustrative discussion of preferred embodiments of the invention.

[0063] EXAMPLES

[0064] EXAMPLE 1: A PROCESS OF PREPARATION OF ZINC SULPHATE MONOHYDRATE IN GRANULAR FORM

[0065] The process comprises of following steps: a) The 40-65% zinc ash was mixed with 20-40% sulphuric acid solution to make a concentrated zinc solution via a reaction process in a reactor with an agitator; b) The concentrated zinc solution of specific gravity 1.40-1.70 gm / cc and 2-4 pH obtained in step (a) was passed through a filter press to screen for impurities in the filtration system; c) The filtered concentrated zinc solution of step (b) was fed to fluidized bed dryer with nozzle spray system; d) The bed of zinc sulphate granules was prepared in a fluidized bed dryer for coating & drying; e) The hot air was blown at high pressure of 400-700 mmwc via a hot air generator to suspend the zinc sulphate granules in the air; f) The concentrated zinc solution of step (c) was sprayed from the nozzle system onto the zinc sulphate granules of step (e) for coating; g) The coated granules was passed for sieving in a rotary shifter to get desired-sized granules by separating the oversized and undersized granules and fed them back into the process; h) The final zinc fertilizer granules and fine powder was stored, separately in a suitable container for packaging.

[0066] EXAMPLE 2: A PROCESS OF PREPARATION OF ZINC SULPHATE MONOHYDRATE IN GRANULAR FORM (Bl)

[0067] The process comprises of following steps: a) fhe 59% zinc ash (TPT) was mixed with 25% sulphuric acid solution (TPT) to make a concentrated zinc solution via a reaction process in a reactor with an agitator; b) The concentrated zinc solution of specific gravity 1.40-1.70 gm / cc and 2-4 pH obtained in step (a) was passed through a filter press to screen for impurities in the filtration system; c) The filtered concentrated zinc solution of step (b) was fed to fluidized bed dryer with nozzle spray system; d) The bed of zinc sulphate granules was prepared in a fluidized bed dryer for coating & drying; e) The hot air was blown at high pressure of 400-700 mmwc via a hot air generator to suspend the zinc sulphate granules in the air; f) The concentrated zinc solution of step (c) was sprayed from the nozzle system onto the zinc sulphate granules of step (e) for coating; g) The coated granules was passed for sieving in a rotary shifter to get desiredsized granules by separating the oversized and undersized granules and fed them back into the process; h) The final zinc fertilizer granules and fine powder was stored, separately in a suitable container for packaging.

[0068] EXAMPLE 3: A PROCESS OF PREPARATION OF ZINC SULPHATE

[0069] MONOHYDRATE IN GRANULAR FORM (B2)

[0070] The process comprises of following steps: a) The 56% zinc ash (TPT) was mixed with 23% sulphuric acid solution (TPT) to make a concentrated zinc solution via a reaction process in a reactor with an agitator; b) The concentrated zinc solution of specific gravity 1.40-1.70 gm / cc and 2-4 pH obtained in step (a) was passed through a filter press to screen for impurities in the filtration system; c) The filtered concentrated zinc solution of step (b) was fed to fluidized bed dryer with nozzle spray system; d) The bed of zinc sulphate granules was prepared in a fluidized bed dryer for coating & drying; e) The hot air was blown at high pressure of 400-700 mmwc via a hot air generator to suspend the zinc sulphate granules in the air; f) The concentrated zinc solution of step (c) was sprayed from the nozzle system onto the zinc sulphate granules of step (e) for coating; g) The coated granules was passed for sieving in a rotary shifter to get desiredsized granules by separating the oversized and undersized granules and fed them back into the process; h) The final zinc fertilizer granules and fine powder was stored, separately in a suitable container for packaging.

[0071] EXAMPLE 4: EVALUATION OF ZINC SULPHATE MONOHYDRATE

[0072] GRANULES

[0073] 4.1: Determination of Shape and Size

[0074] Three distinct granules were manually tested using sieves with mesh sizes of 1- 2mm and 2-4mm. Result:

[0075] Table 1: Data for Uniformity with sieve size 1-2 mm

[0076] Table 2: Data for Uniformity with sieve size 2-4 mm

[0077] From the results, it can be concluded that the granules prepared by process of the present invention are of uniform shape and size.

[0078] 4.2: DETERMINATION OF GRANUEE STRENGTH Granule strength of zinc sulphate granules of the present invention was evaluated against granules available in the market by keeping it in a granules hardness testing machine and crushed using force. Result:

[0079] Table 3: Data for Granule Strength

[0080] From the results, it can be concluded that the zinc sulphate granules of the present invention are at least 100-300% harder than the granules available in the market.

[0081] 4.3: DETERMINATION OF WATER SOLUBILITY:

[0082] The granules of the present invention was evaluated for water solubility against existing Granules in the Market. PROCESS: a. 5gm of Zinc Sulphate Granules were added into three different Beakers with 500ml Water, b. Shaker was switched on 15 mins to check solubility of Granules c. Then the liquid was sieved in another beaker with help of muslin cloth d. Remaining powder was weighed on a small weighing scale

[0083] Result:

[0084] Table 4: Solubility of Granules From the results, it can be concluded that the granules of the present invention have 100% solubility against the granules available in the market. 4.4: DETERMINATION OF FUEL AND POWER CONSUMPTION

[0085] The zinc sulphate granules of the present invention were evaluated for power & energy saving against granules available in the market.

[0086] Process: a) Coal Consumption for both processes were compared as per existing machinery setup. b) Power Consumption for both processes were compared as per existing machinery setup. For old process first power consumption to make zinc sulphate monohydrate power for calculated then power consumption to make zinc sulphate granules from powder was added to get final power consumption.

[0087] Result:

[0088] Table 5: Data for Fuel Consumption

[0089] Table 6: Data for Power Consumption

[0090] From the results, it can be concluded that the process of the present invention saves 10% Fuel / hour & 31% of Power due to lower HP consumption. 4.5: DETERMINATION OF MIXING POTENTIAL TO CREATE A

[0091] HOMOGENOUS MIXTURE

[0092] The homogenous mixing potential was evaluated in a Rotary Drum mixer with granules available in the market.

[0093] Details of the process: Table 7: Details for Mixing Potential

[0094] Result:

[0095] Table 8: Data for Mixing Potential

[0096] Based on the results, it can be concluded that creating a homogeneous fertilizer mixture is not feasible with the currently manufactured granules. However, the granules prepared with the present invention have achieved near-perfect homogeneity due to their superior strength and uniform shape.

[0097] 4.6: DETERMINATION OF DUST GENERATION

[0098] 5 For the determination of dust generation, bags were stacked and dropped as per market standards and then checked for dust generation.

[0099] Process:

[0100] Jumbo Bags are dropped from a Pallet Stacker (Twice) & 50 Kg Bags were dropped 10 using the Indian Institute of Packaging standards of dropping bags 6 times from waist height on all six sides of the bags i.e. Top, Bottom, Front, Back and both sides. After dropping the bags, they were opened and the material was sieved using a stainless steel (SS) wire mesh sieve, Granules were weighed separately and powder generated was weighed separately and then the data was recorded.

[0101] Result:

[0102] Table 9: Data for Dust Generation

[0103] From the results it can be concluded that the granules of the present invention does 20 not generate any dust after lifting and dropping the bags multiple times, However, the granules currently being Manufactured generate a substantial amount of Dust due to low strength.

[0104] 4.7: FORTIFICATION OF ZINC SULPHATE GRANULES WITH DIFFERENT MICRONUTRIENTS

[0105] Filtered Feed was stored in Stock Tank and was added with desired quantity of Micronutrient required for Fortification. For Example, in a Feed of 5000 Litres to get 0.1% Boron 25 Kg of Boron 20% was added then it was mixed with help of an agitator, this feed was then sent to the dryer.

[0106] Result:

[0107] Table 10: Data for Fortification Potential

[0108] Based on the results, it can be concluded that fortification is possible in the granules of the present invention. Fortifying zinc granules offer a distinct advantage, as farmers only need to apply a single product to provide the crop with the necessary nutrients, eliminating the need for 2-3 different products.

[0109] 4.8: DETERMINATION OF POROSITY & COATING CAPABILITY

[0110] The granules of the present invention were tested for the porosity & coating capability using pan coating drum against existing zinc sulphate granules in the market. Process: a) A Mixture of Boron Liquid was made in a tank by dissolving Boron 20%; b) The liquid was coated on top of granules in three different ratios i.e. 1%, 2% & 3%. 1% = 1000 Kg Zinc Sulphate Granules x 1% = 10 Liters of Boron Liquid was sprayed on 1000 Kg of Granules

[0111] 2% = 1000 Kg Zinc Sulphate Granules x 1% = 20 Liters of Boron Liquid was sprayed on 1000 Kg of Granules

[0112] 3% = 1000 Kg Zinc Sulphate Granules x 3% = 30 Liters of Boron Liquid was sprayed on 1000 Kg of Granules c) Granules were passed through a 2mm Sieve to see how many Granules are hard enough to pass through the sieve; d) Granules were tested for Hardness and Seaworthiness post Coating in a Pan Coating Drum.

[0113] Result: Table 11: Data for Coating Capability & Porosity

[0114] Based on the results, it can be concluded that the granules have minimum 3% coating capability, whereas the existing granules immediately break down and do not have enough structural strength for transportation thereby they are not seaworthy.

[0115] Based on the above study data, it can be concluded that the process for preparing zinc fertilizer in granular form, as described in the present invention, yields granules with high strength, excellent solubility, uniform shape and size, while also being fuel and power efficient.

Claims

CLAIMSWe Claim,1) A novel process of preparation of zinc fertilizer in granular form comprises of following steps: a) mixing zinc ash with sulphuric acid solution to make concentrated zinc solution via a reaction process in a reactor with an agitator; b) passing concentrated zinc solution obtained in step (a) through a filter press to screen for impurities in the filtration system; c) feeding filtered concentrated zinc solution of step (b) to fluidized bed dryer with nozzle spray system; d) preparing the bed of zinc sulphate granules in a fluidized bed dryer for coating & drying; e) blowing the hot air at high pressure via a hot air generator to suspend the zinc sulphate granules in the air; f) spraying the concentrated zinc solution of step (c) from the nozzle system onto the zinc sulphate granules of step (e) for coating; g) passing the coated granules for sieving in a rotary shifter to get desired- sized granules by separating the oversized and undersized granules and feeding them back into the process; h) storing final zinc fertilizer granules and fine powder, separately in a suitable container for packaging.2) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said zinc fertilizer is zinc sulphate monohydrate.3) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1, wherein said zinc sulphate monohydrate granules are directly prepared using concentrated zinc solution without converting the solution into powder first.4) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said zinc ash is used in the range of 40-65% (w / w).5) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said sulphuric acid solution is prepared using 20-40%(w / w) sulphuric acid in water.6) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said zinc ash is of 50-70% purity and said sulphuric acid used is 98% purity.7) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said zinc sulphate granules filled in the FBD to make a bed of 400 - 700 Kg.8) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said zinc fertilizer comprising of an effective amount of Zinc, wherein the Zinc sulphate monohydrate can be in the range of 15-36% (w / w) with or without a binding agent or dispersing agent in granular form.9) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein the temperature of the fluidized bed dryer is 120- 160°C.10) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said zinc fertilizer comprises a micronutrient fertilizer.11) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said zinc fertilizer are of particle size 1 mm to 10 mm.12) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said fertilizer having 100% solubility in water, enabling complete dissolution and improved solubility.13) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said fertilizer are 100-300% harder.14) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said process saves 5-20% fuel / hour.15) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said process saves 15-32% power.16) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said fertilizer is of uniform shape, uniform size, dispersibility, and porosity.17) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said fertilizer having lower dust levels compared to compaction granules.18) The novel process of preparation of zinc fertilizer in granular form as claimed in claim 1 wherein said fertilizer can be fortified by l%-3% coating with other micronutrients including but not limited to Boron, Molybdenum, Copper, and Manganese.

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