DESC:This is an application for a patent of addition to the Indian patent application No. 350/MUM/2014 filed on 31st January 2014, the entire contents of which are specifically incorporated herein by reference.
FIELD
The present disclosure relates to fertilizer products and their process of preparation.
BACKGROUND
Fertilizers are the auxiliary chemicals supplied to plants in order to externally provide nutrients essential for their growth. Fertilizers may be of inorganic or organic nature and are typically in forms such as solid - granulated or powdered, liquid, semisolid and aerosol. They contain a wide range of ingredients such as manure, bat guano, compost, peat moss, wood ash, nitrogen, phosphorus and potassium, calcium, sulphur, iron, zinc and magnesium.
Sulphur is an extremely vital element required for the growth of plants and can be provided to plants via fertilizers either in its elemental form or in its inorganic form such as sulphate (SO42-) or as sulphur dioxide (SO2) from the atmosphere. Elemental sulphur can, however, be only absorbed by plants once it is oxidized to sulphate by soil bacteria in the presence of moisture/water. Furthermore, elemental sulphur can be used with or without carrier medium such as mineral clay, which is used as a soil additive, and it must be in finely divided form for quick microbial action to get converted into water soluble sulphates to be taken by plants. Micronized sulphur in its elemental form is slowly oxidized to sulphates by soil bacteria such as Thiobacillus. Addition of sulphur enhances availability of necessary nutrients in the soil for plants or crops, which results in improvement in the quality and yield of the agricultural crops. Furthermore, sulphur in its elemental form acts as a pesticide and/or a fungicide against certain soil pests and micro-organisms. Sulphur is suitably applied in its elemental form and upon blending produces dust particles which are harmful to the eyes and hazardous for health.
A hot process to reduce the dust formation by mixing bentonite clay with sulphur is known. In the hot process, molten sulphur is used to coat the bentonite clay during production stage. Upon application to soil, the bentonite clay breaks up to release sulphur particles. The molten hydrophobic sulphur, that coats the bentonite clay using hot process, prevents bentonite clay from picking up water and swelling quickly. Hence, hot process utilizing molten sulphur pellets does not quickly disperse into fine sulphur particles resulting into slower oxidation of sulphur.
In 350/MUM/2014, there is disclosed a process for preparation of a fertilizer product comprising elemental sulphur, at least one swelling agent, at least one binding agent, at least one plant growth regulator, and optionally at least one inorganic material. The fertilizer product, as disclosed in 350/MUM/2014, increases the water holding capacity and slowly releases the ingredients which make the fertilizer product very well suited for agriculture and horticulture related application. However, the dispersion time of the fertilizer product and the conversion rate of sulphur to sulphate are less.
Therefore, there exists a need for developing an effective fertilizer product containing elemental sulphur that mitigates the drawbacks associated with the conventional sulphur containing fertilizers.
OBJECTS
Some of the objects of the present disclosure, of which at least one embodiment is adapted to provide, are described herein below:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a fertilizer product with improved dispersion properties.
Another object of the present disclosure is to provide a fertilizer product with improved conversion of sulphur to sulphates.
Still another object of the present disclosure is to provide a process for the preparation of a fertilizer product.
Other objects and advantages of the present disclosure will be more apparent from the following description which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a fertilizer product and process for the preparation thereof.
In one aspect of the present disclosure, there is provided a fertilizer product which comprises micronized elemental sulphur having particle size ranging from 45 µm to 250 µm, in an amount ranging from 70 wt% to 97 wt% of the total weight of the fertilizer product; at least one dispersing agent in an amount ranging from 0.1 wt% to 1 wt% of the total weight of the fertilizer product; at least one swelling agent in an amount ranging from 0.1 wt% to 10 wt% of the total weight of the fertilizer product; at least one binding agent in an amount ranging from 0.3 wt% to 30 wt% of the total weight of the fertilizer product; at least one sulphur solubilizing microbe having a concentration in the range of 105 cells/ml to 1010 cells/ml; and at least one mineral clay in an amount ranging from 0.5 wt% to 30 wt% of the total weight of the fertilizer product; and at least one plant growth hormone in an amount ranging from 0.001 wt% to 1 wt% of the total weight of the fertilizer product. The fertilizer product is in the form of shaped articles selected from the group consisting of pellets, pastilles, extrudates, beads, flakes, and granules.
The fertilizer product is characterized by moisture content ranging from 0.1 wt% to 1.0 wt%, dispersion time in the range of 2 minutes to 300 minutes and pH of the product upon dispersion into soil is in the range of 6.5 to 2.5.
The swelling of the fertilizer product is in the range of 20 % to 100 % of the volume of the fertilizer product.
The size of the fertilizer product is in the range of 1.5 mm to 4 mm.
In another aspect of the present disclosure, there is provided a process for the preparation of the fertilizer product. The process comprises preparing a mixture, at a temperature ranging from 15 oC to 40 oC, by admixing micronized elemental sulphur; at least one dispersing agent; at least one swelling agent; at least one binding agent; at least one sulphur solubilizing microbe; at least one mineral clay; water; and at least one plant growth hormone. The so formed mixture undergoes pugging followed by kneading to obtain a dough. The dough is processed to obtain shaped articles such as pellets, pastilles, extrudates, beads, flakes, and granules by at least one method selected from the group consisting of pelletizing, pastilling, extruding and granulating. Further, the shaped articles are dried at a temperature ranging from 25 oC to 50 oC to obtain the fertilizer product.

DETAILED DESCRIPTION
Sulphur is an extremely essential element required for the growth of plants and can be provided to plants via fertilizer either in its elemental form or in its inorganic form such as sulphates (SO42-). Elemental sulphur can, however, be only absorbed by plants once it is oxidized to sulphate by soil bacteria in the presence of moisture/water. The blending of elemental sulphur while preparing fertilizers lead to dust formation which is harmful to eyes and hazardous for health. Some fertilizers additionally contain mineral clay, such as bentonite clay, which is used as a soil additive. Bentonite clay absorbs the water which leads to swelling of the fertilizer and disperses the sulphur quickly. However, mixing of elemental sulphur with bentonite clay in hot process leads to coating of bentonite clay. This molten sulphur coating of bentonite clay prevents bentonite from absorbing water from the surrounding soil and hence avoids swelling and dispersion of the elemental sulphur which is not desired.
The present disclosure envisage to formulate elemental sulphur bodies like pellets, extrudates or beads as a fertilizer or suitable for fertilizer composition with other soil nutrients, which can rapidly disintegrate and disperse into fine particles upon contact with water or moisture present in the soil and improve oxidation of sulphur to sulphates.
In one aspect of the present disclosure, there is provided a fertilizer product. The product is in the form of shaped articles selected from the group consisting of pellets, pastilles, extrudates, beads, flakes, and granules, having size in the range of 1.5 mm to 3 mm.
The fertilizer product comprises micronized elemental sulphur having particle size ranging from 45 µm to 250 µm, in an amount ranging from 70 wt% to 97 wt% of the total weight of the fertilizer product, preferably from 87 wt% to 97 wt% of the total weight of the fertilizer product; at least one dispersing agent in an amount ranging from 0.1 wt% to 1 wt% of the total weight of the fertilizer product; at least one swelling agent in an amount ranging from 0.1 wt% to 10 wt% of the total weight of the fertilizer product, preferably from 0.5 wt% to 5.0 wt% of the total weight of the fertilizer product; at least one binding agent in an amount ranging from 0.3 wt% to 30 wt% of the total weight of the fertilizer product, preferably from 0.9 wt% to 13 wt% of the total weight of the fertilizer product; at least one sulphur solubilizing microbe having a concentration in the range of 105 cells/ml to 1010 cells/ml; at least one mineral clay in an amount ranging from 0.5 wt% to 30 wt% of the total weight of the fertilizer product, preferably from 2 wt% to 13 wt% of the total weight of the fertilizer product; and at least one plant growth hormone in an amount ranging from 0.001 wt% to 1 wt% of the total weight of the fertilizer product, preferably from 0.005 wt% to 1 wt% of the total weight of the fertilizer product.
Micronized elemental sulphur being an extremely important nutrient for plants, demonstrates a wide array of activities. Sulphur enhances availability of the necessary plant nutrients in the soil, which improves the quality and yield of the agricultural crops.
Further, sulphur is a vital element necessary for the synthesis of entities such as sulphur-containing amino acids and proteins, coenzyme A, biotin, thiamine, glutathione, chlorophyll, lipids and volatile oils. Furthermore, sulphur in its elemental form, acts as a pesticide and/or a fungicide against certain soil pests and micro-organisms.
In one embodiment of the present disclosure, the purity of the elemental sulphur is more than 99%, obtained from Claus process post hydrodesulphurization in oil refinery.
In accordance with the embodiments of the present disclosure, the dispersing agent can be selected from the group consisting of sodium salt of naphthalene sulphonate condensate, sodium alkyl naphthalene sulphonate blend, polyurethane, polyacrylate based dispersing agent, and calcium lignosulphonate. The dispersing agent enhances effectiveness of elemental sulphur fertilizer by the rapid dispersion of formed pellets, pastilles, extrudates, beads, flakes, and granules into fine sulphur particles in the soil, having particle size in the range of 45-70 µm. The fine sulphur particles oxidize more quickly into sulphates that are absorbed quickly by plants as compared to larger sulphur particles.
In one embodiment of the present disclosure, the dispersing agent is sodium salt of naphthalene sulphonate condensate.
In accordance with the embodiments of the present disclosure, the swelling agent can be selected from the group consisting of polyacrylic acid, polyacrylamide polymer, cellulose grafted polyacrylamide polymer, potassium salt of cellulose grafted polyacrylamide and starch grafted polyacrylamide. The function of the swelling agent is to absorb water present in the surrounding soil area such as irrigated water or precipitated atmospheric moisture once the fertilizer product is introduced in the soil. The product swells upon imbibition of water that lead to breaking of pellets, pastilles, extrudates, beads, flakes and granules to release fine sulphur particles along with other ingredients such as the plant growth hormone across a very wide perimeter.
In one embodiment of the present disclosure, the swelling agent is potassium salt of polyacrylamide grafted cellulose.
It is important to note that the fertilizer products with low swelling agent content have good applicability in lands with high water content. This is because less quantity of swelling agent leads to less water holding capacity which is acceptable for high water content lands. Similarly, fertilizer products with high swelling agent content have a high water holding capacity and are thus useful for the regions facing water scarcity.
In accordance with the embodiments of the present disclosure, the binding agent can be selected from the group consisting of carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropylmethyl cellulose, hydroxyethylpropyl cellulose, corn starch, potato starch, starch acetates, ionic starches, polyvinyl alcohol, polyvinyl acetate, polyethylene glycol and polylactic acid. Binding agents are included in the fertilizer product of the present disclosure to facilitate effective binding between micronized elemental sulphur and the other ingredients in order to form an aesthetic and uniform fertilizer product.
In one embodiment of the present disclosure, the binding agent is ethyl cellulose.
In accordance with the embodiments of the present disclosure, the sulphur solubilizing microbe can be selected from the group consisting of Thiobacillus thiooxidans, Thiobacillus ferroxidans, Thiobacillus thioparus, Thiobacillus prosperus, Thiobacillus intermedius, Beggiatoa, and Thiobacillus denitrificans. The dispersing agent very rapidly disperses the elemental sulphur particles into fine sulphur particles. The dispersed fine sulphur particles are oxidized into sulphate form by the sulphur solubilizing microbe, which acidifies the soil in the range of 6.5 to 2.5, and enables bioavailability of sulphate and other essential minerals. The quick absorption of sulphate by the soil results in improved nutrition in the soil and enhanced crop yield.
In one embodiment of the present disclosure, the sulphur solubilizing microbe is Thiobacillus thiooxidans.
Thiobacillus thiooxidans (ATCC-8085) is purchased from American Type Culture Collection, USA, through their Indian agent M/s, LGC Promochem India Pvt. Ltd., Bangalore.
In accordance with the embodiments of the present disclosure, the mineral clay can be selected from the group consisting of kaolin, attapulgite, and bentonite. The mineral clay facilitates the fertilizer product to absorb moisture from the soil. The absorption of moisture from the soil leads to swelling and disintegration of the fertilizer product into fine particles, which are suitable for oxidation.
In one embodiment of the present disclosure, the mineral clay is kaolin.
In accordance with the embodiments of the present disclosure, the plant growth hormone can be selected from the group consisting of auxins, gibberellins, cytokinins, and abscisic acid (ABA) which are indole-3-acetic acid (IAA), gibberellic acid (GA), and 6-benzyl adenine (BA), respectively. The plant growth hormone is added to the fertilizer product of the present disclosure to increase the yield of the crops.
In accordance with one embodiment of the present disclosure, the plant growth hormone is gibberellic acid.
The fertilizer product of the present disclosure is in the form of shapes such as pellets, pastilles, extrudates, beads, flakes, and granules, which are rapidly dispersed into fine particles of sulphur in the soil using dispersing agents. The dispersed fine particles of sulphur oxidize faster as compared to larger particles. Oxidation of the dispersed fine particles of sulphur into sulphates occurs in the presence of the sulphur solubilizing microbes. As the rate of oxidation of fine particles is greater than that of larger particles, more quantity of sulphur is available to plants in the form of sulphate, thereby improving the quality and the yield of the plants. The fertilizer product is more suitable for oilseed crops such as sunflower seeds, groundnuts, soybeans, and the like.
The fertilizer product has moisture content in the range of 0.1 wt% to 1.0 wt%, dispersion time in the range of 2 minutes to 300 minutes and pH of the product upon dispersion into soil is in the range of 6.5 to 2.5, which is suitable for plants, soil, and microbes. The fertilizer product can swell in the range of 20 % to 100 % of the volume of the fertilizer product.
In accordance with another aspect of the present disclosure, there is provided a process for the preparation of a fertilizer product. The process comprises preparing a mixture, at a temperature ranging from 15 oC to 40 oC, by admixing micronized elemental sulphur; at least one dispersing agent; at least one swelling agent; at least one binding agent; at least one sulphur solubilizing microbe; at least one mineral clay; at least one plant growth hormone; and water.
The amount of water used is in an amount ranging from 5 wt% to 60 wt% of the total weight of the fertilizer product, to facilitate the formation of dough.
Further, the process includes pugging and kneading of the so formed mixture to obtain a dough, followed by the processing of the so formed dough to obtain shaped articles. The meaning of the term ‘pugging’ includes working the mixture into a soft, plastic condition without air pockets; thereby making it suitable for further processing. The shaped articles upon drying at a temperature in the range of 25 oC to 50 oC yield the fertilizer product of the present disclosure.
In accordance with an embodiment of the present disclosure, the step of processing is at least one selected from the group consisting of pelletizing, pastilling, extruding, and granulating, and the shaped article is at least one selected from the group consisting of pellets, pastilles, extrudates, beads, flakes, and granules.
A characteristic feature of the present disclosure is the inclusion of both the swelling agent and the binding agent enabling the admixing at an ambient temperature which significantly eases the processing and handling and makes the process cost effective.
The processing steps of pelletizing, pastilling, extruding and granulating to prepare a fertilizer product results in shaped articles having definitive macromolecular dimensions. This is a special feature of the product of the present disclosure which is associated with advantages such as obviation of the problems accompanying sulphur dust, increase in the water holding capacity and rapid dispersion of micronized elemental sulphur extrudates, pellets, flakes, spheres and beads; thereby making the product very well suited for agriculture and horticulture related applications. Furthermore, some of the essential ingredients used in the product are heat sensitive on exposure to elevated temperatures (above 100 oC) during the process of preparation. Therefore, the processes which can be carried out at ambient temperatures, such as the present process, are favored.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTS
Comparative Experiment 1: 90 g of micronized elemental sulphur was mixed with 9.6 g of kaolin, 0.2 g of sodium lignosulphonate and 0.2 g of naphthalene sulphonate on dry weight basis at 30 °C and at atmospheric pressure to obtain a mixture. 15 ml of water was added to the mixture. Pugging of the so formed mixture was done followed by kneading to obtain a dough. The so formed dough was then extruded to obtain extrudates, having 3 mm size, using an extruder. The so formed extrudates were air dried at 35 °C. The moisture content of the dried extrudates was found to be less than 1 wt% on dry weight basis.
10 g of so formed extrudates were added in 100 ml of water. It was observed that, the extrudates completely dispersed in the range of 45 to 70 micron size within 60 minutes. The dispersed extrudates showed reduction in pH from 4.5 to 4.3 within 30 days. The sulphate concentration of the solution was measured using UV/Vis spectrophotometer at 420 nm and was found to be 20 ppm within 30 days.

Comparative Experiment 2: 90 g of micronized elemental sulphur was mixed with 9.7 g of kaolin, 0.1 g of sodium lignosulphonate, 0.1 g sodium alkyl naphthalene sulphonate blend and 0.1 g of sodium salt of naphthalene sulphonate condensate on dry weight basis at 30 °C and at atmospheric pressure to obtain a mixture. 22 ml of water was added to the mixture. Pugging of the so formed mixture was done followed by kneading to obtain a dough. The so formed dough was then extruded to obtain extrudates, having 3 mm size, using an extruder. The so formed extrudates were air dried at 35 °C. The moisture content of the dried extrudates was found to be less than 1 wt% on dry weight basis.
10 g of so formed extrudates were added in 100 ml of water. It was observed that, the extrudates completely dispersed in the range of 45 to 70 micron size within 120 minutes. The dispersed extrudates showed reduction in pH from 4.5 to 4.1 within 30 days. The sulphate concentration of the solution was measured using UV/Vis spectrophotometer at 420 nm and was found to be 40 ppm within 30 days.
Comparative Experiment 3: 90.5 g of micronized elemental sulphur was mixed with 7.5 g of kaolin, 1.0 g of potassium salt of polyacrylamide grafted cellulose and 1.0 g of ethyl cellulose on dry weight basis at 30 °C and at atmospheric pressure to obtain a mixture. To this mixture, 8.6 ml of Thiobacillus thiooxidans solution (107 cells/ml) (Thiobacillus thiooxidans (ATCC-8085) was purchased from American Type Culture Collection, USA, through their Indian agent M/s, LGC Promochem India Pvt. Ltd., Banglore) and 15 ml of water were added with continuous mixing. Pugging of the so formed mixture was done followed by kneading to obtain a dough. The so formed dough was then extruded to obtain extrudates, having 3 mm size, using an extruder. The so formed extrudates were air dried at 35 °C. The moisture content of the dried extrudates was found to be less than 1 wt% on dry weight basis which was named as Sample-T. Reference sample was prepared by keeping all the ingredients in the same concentration without adding Thiobacillus thiooxidans (ATCC-8085) solution and denoted as Sample-K.
10 g of so formed extrudates were added in 100 ml of water. It was observed that, Reference Sample-T extrudates completely dispersed -in the range of 45 to 70 micron size within 30 minutes, whereas Reference Sample-K extrudates completely dispersed -in the range of 45 to 70 micron size within 60 minutes. The Sample-T and Sample-K extrudates when dispersed in a suitable medium containing micronutrients, such as ammonium sulphate, monopotassium phosphate, calcium chloride, ferrous sulphate, and magnesium sulphate, showed reduction in pH from 4.5 to 3.1 and 4.5 to 4.3, respectively within 30 days. Sulphate concentration of the Sample-T and Sample-K solution was measured using UV/Vis spectrophotometer at 420 nm and was found to be 96 ppm and 20 ppm, respectively within 30 days. The results showed that Sample-T has higher pH reduction due to addition of Thiobacillus thiooxidans and sulphate formation as compared to the reference Sample-K.
Comparative Experiment 4: 90.5 g of micronized elemental sulphur was mixed with 8.3 g of kaolin, 0.2 g of sodium salt of naphthalene sulphonate condensate and 1.0 g of ethyl cellulose on dry basis at 30 °C and at atmospheric pressure to obtain a mixture. To this mixture, 8.6 ml of concentrated Thiobacillus thiooxidans solution (107 cells/ml) (ATCC-8085) and 15 ml of water were added with continuous mixing of powder. Pugging of the so formed mixture was done followed by kneading to obtain a dough. The so formed dough was then extruded to obtain extrudates, having 3 mm size, using an extruder. The so formed extrudates were air dried at 35 °C. The moisture content of the dried extrudates was found to be less than 1 wt% on dry weight basis.
10 g of so formed extrudates were added in 100 ml of water. It was observed that, the extrudates completely dispersed -in the range of 45 to 70 micron size within 30 minutes. Similar behavior in terms of pH reduction and sulphate formation was observed as shown in comparative experiment 3. The dispersed extrudates showed reduction in pH from 4.5 to 3.1 within 30 days. The sulphate concentration of the solution was measured using UV/Vis spectrophotometer at 420 nm and was found to be 96 ppm within 30 days.
Comparative Experiment 5: 90.5 g of micronized elemental sulphur was mixed with 6.3 g of kaolin, 0.2 g of sodium salt of naphthalene sulphonate condensate, 1.0 g of ethyl cellulose and 2 g potassium salt of ployacrylamide grafted cellulose at 30 °C and at atmospheric pressure to obtain a mixture. To this mixture, 8.6 ml of concentrated Thiobacillus thiooxidans solution (107 cells/ml) (ATCC-8085) and 15 ml of water were added with continuous mixing of powder. Pugging of the so formed mixture was done followed by kneading to obtain a dough. The so formed dough was then extruded to obtain extrudates, having 3 mm size, using an extruder. The so formed extrudates were air dried at 30 °C. The moisture content of the dried extrudates was found to be less than 1 wt% on dry weight basis.
10 g of so formed extrudates were added in 100 ml of water. It was observed that, the extrudates completely dispersed -in the range of 45 to 70 micron size within 30 minutes. Similar behavior in terms of pH reduction and sulphate formation was observed as shown in comparative experiment 3. The dispersed extrudates showed reduction in pH from 4.5 to 3.1 within 30 days. The sulphate concentration of the solution was measured using UV/Vis spectrophotometer at 420 nm and was found to be 96 ppm within 30 days.
Fertilizer product in accordance with the present disclosure
Experiment 6: 91 g of micronized elemental sulphur was mixed with 7 g of kaolin, 0.2 g of sodium salt of naphthalene sulphonate condensate, 0.995 g of ethyl cellulose, 2 g potassium salt of ployacrylamide grafted cellulose and 0.005 g of gibberellic acid (GA) at 30 °C and at atmospheric pressure to obtain a mixture. To this mixture, 8.6 ml of concentrated Thiobacillus thiooxidans solution (107 cells/ml) (ATCC-8085) and 15 ml of water were added with continuous mixing of powder. Pugging of the so formed mixture was done followed by kneading to obtain a dough. The so formed dough was then extruded to obtain extrudates, having 3 mm size, using an extruder. The so formed extrudates were air dried at 35 °C. The moisture content of the dried extrudates was found to be less than 1 wt% on dry weight basis.
10 g of so formed extrudates were added in 100 ml of water. It was observed that, the extrudates completely dispersed in the range of 45 to 70 micron size within 20 minutes. The dispersed extrudates showed reduction in pH from 4.5 to 2.3 within 30 days. The sulphate concentration of the solution was measured using UV/Vis spectrophotometer at 420 nm and was found to be 99 ppm within 30 days.
Table 1 below shows the details of comparative experiments 1-5 and of experiment 6 (of the present disclosure).
Table 1: Details of Experiments 1-6
Ingredients Exp. 1 Exp. 2 Exp. 3
Sample-T Exp. 3
Sample-K Exp. 4 Exp. 5 Exp. 6
Present Disclosure
1 Elemental Sulphur 90 g of micronized elemental sulphur 90 g of micronized elemental sulphur 90.5 g of micronized elemental sulphur 90.5 g of micronized elemental sulphur 90.5 g of micronized elemental sulphur 90.5 g of micronized elemental sulphur 91 g of micronized elemental sulphur
2 Dispersing Agent 0.2 g of sodium lignosulphonate
0.2 g of naphthalene sulphonate 0.1 g of sodium lignosulphonate
0.1 g sodium alkyl naphthalene sulphonate blend
0.1 g of sodium salt of naphthalene sulphonate condensate 0.2 g of sodium salt of naphthalene sulphonate condensate 0.2 g of sodium salt of naphthalene sulphonate condensate 0.2 g of sodium salt of naphthalene sulphonate condensate
3 Swelling agent 1.0 g of potassium salt of polyacrylamide grafted cellulose 1.0 g of potassium salt of polyacrylamide grafted cellulose 2 g potassium salt of ployacrylamide grafted cellulose 2 g potassium salt of ployacrylamide grafted cellulose
4 Binding agent 1.0 g of ethyl cellulose 1.0 g of ethyl cellulose 1.0 g of ethyl cellulose 1.0 g of ethyl cellulose 0.995 g of ethyl cellulose
5 Sulphur Solubilizing Microbe 8.6 ml of Thiobacillus thiooxidans solution (107 cells/ml) 8.6 ml of concentrated Thiobacillus thiooxidans solution (107 cells/ml)
8.6 ml of concentrated Thiobacillus thiooxidans solution (107 cells/ml) 8.6 ml of concentrated Thiobacillus thiooxidans solution (107 cells/ml)
6 Mineral clay
9.6 g of kaolin 9.7 g of kaolin 7.5 g of kaolin 7.5 g of kaolin 8.3 g of kaolin
6.3 g of kaolin 7 g of kaolin
7 Plant growth hormone 0.005 g of gibberellic acid (GA)

Properties of sample fertilizer products of Experiments 1-6
Exp. 1 Exp. 2 Exp. 3
Sample-T Exp. 3
Sample-K Exp. 4 Exp. 5 Exp. 6
Present Disclosure
Dispersion Extrudates completely dispersed in the range of 45 to 70 micron size within 60 minutes Extrudates completely dispersed in the range of 45 to 70 micron size within 120 minutes.
Extrudates completely dispersed in the range of 45 to 70 micron size within 30 minutes Extrudates completely dispersed in the range of 45 to 70 micron size within 60 minutes Extrudates completely dispersed in the range of 45 to 70micron size within 30 minutes Extrudates completely dispersed in the range of 45 to 70 micron size within 30 minutes Extrudates completely dispersed in the range of 45 to 70 micron size within 20 minutes
pH reduction Reduction in pH from 4.5 to 4.3 within 30 days Reduction in pH from 4.5 to 4.1 within 30 days Reduction in pH from 4.5 to 3.1 within 30 days Reduction in pH from 4.5 to 4.3 within 30 days Reduction in pH from 4.5 to 3.1 within 30 days Reduction in pH from 4.5 to 3.1 within 30 days Reduction in pH from 4.5 to 2.3 within 30 days
Sulphur to sulphates conversion Sulphate concentration 20 ppm within 30 days Sulphate concentration 40 ppm within 30 days Sulphate concentration 96 ppm within 30 days Sulphate concentration 20 ppm within 30 days Sulphate concentration 96 ppm within 30 days Sulphate concentration 96 ppm within 30 days Sulphate concentration 99 ppm within 30 days

The comparative study of experiment 6 and comparative experiments 1 to 5 clearly indicates that the fertilizer product of the present disclosure (experiment 6) having dispersing agent and sulphur solubilizing microbe has faster dispersion, higher pH reduction capacity and higher sulphur to sulphates conversion capacity as compared to fertilizer product without dispersing agent and sulphur solubilizing microbe.
TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of:
- a dust-free, economical, toxic metal-free elemental sulphur and a sulphur solubilizing microbe containing fertilizer product as a feed for horticultural purposes;
- a fertilizer product for plant nourishment;
- a fertilizer product that is of multi-functional nature as it provides rapid dispersion of sulphur pellets, pastilles and the like into fine sulphur particles, as the dispersed fine sulphur particles oxidize more quickly to sulphate forms;
- a simple, effective and economic process for the preparation of a fertilizer product with desired mechanical strength; and
- a fertilizer product that is biodegradable and safe to handle in the field.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:
1. A fertilizer product comprising:
i. micronized elemental sulphur having particle size ranging from 45 µm to 250 µm, in an amount ranging from 70 wt% to 97 wt% of the total weight of the fertilizer product;
ii. at least one dispersing agent in an amount ranging from 0.1 wt% to 1 wt% of the total weight of the fertilizer product;
iii. at least one swelling agent in an amount ranging from 0.1 wt% to 10 wt% of the total weight of the fertilizer product;
iv. at least one binding agent in an amount ranging from 0.3 wt% to 30 wt% of the total weight of the fertilizer product;
v. at least one sulphur solubilizing microbe having a concentration in the range of 105 cells/ml to 1010 cells/ml;
vi. at least one mineral clay in an amount ranging from 0.5 wt% to 30 wt% of the total weight of the fertilizer product; and
vii. at least one plant growth hormone in an amount ranging from 0.001 wt% to 1 wt% of the total weight of the fertilizer product.
2. The fertilizer product as claimed in claim 1, is characterized by moisture content ranging from 0.1 wt% to 1.0 wt%, dispersion time in the range of 2 minutes to 300 minutes and pH of said product upon dispersion into soil is in the range of 6.5 to 2.5.
3. The fertilizer product as claimed in claim 1, wherein the swelling of the fertilizer product is in the range of 20 % to 100 % of the volume of the fertilizer product.
4. The fertilizer product as claimed in claim 1, in the form of shaped articles selected from the group consisting of pellets, pastilles, extrudates, beads, flakes, and granules.
5. The fertilizer product as claimed in claim 4, wherein said shaped articles have a size ranging from 1.5 mm to 4 mm.
6. The fertilizer product as claimed in claim 1, wherein said dispersing agent is selected from the group consisting of sodium salt of naphthalene sulphonate condensate, sodium alkyl naphthalene sulphonate blend, polyurethane, polyacrylate based dispersing agent, and calcium lignosulphonate.
7. The fertilizer product as claimed in claim 1, wherein swelling agent is selected from the group consisting of polyacrylic acid, polyacrylamide, cellulose grafted polyacrylamide, potassium salt of polyacrylamide, and starch grafted polyacrylamide.
8. The fertilizer product as claimed in claim 1, wherein said binding agent is selected from the group consisting of carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropylmethyl cellulose, hydroxyethylpropyl cellulose, corn starch, potato starch, starch acetates, ionic starches, polyvinyl alcohol, polyvinyl acetate, polyethylene glycol, and polylactic acid.
9. The fertilizer product as claimed in claim 1, wherein said sulphur solubilizing microbe is selected from the group consisting of Thiobacillus thiooxidans, Thiobacillus ferroxidans, Thiobacillus thioparus, Thiobacillus prosperus, Thiobacillus intermedius, Beggiatoa, and Thiobacillus denitrificans.
10. The fertilizer product as claimed in claim 9, wherein said sulphur solubilizing microbe is Thiobacillus thiooxidans.
11. The fertilizer product as claimed in claim 1, wherein said mineral clay is selected from the group consisting of kaolin, attapulgite, and bentonite.
12. The fertilizer product as claimed in claim 1, wherein said plant growth hormone is selected from the group consisting of auxins, gibberellins, cytokinins, and abscisic acid.
13. The plant growth hormone as claimed in claim 12, wherein said plant growth hormone is selected from the group consisting of indole-3-acetic acid, gibberellic acid, and 6-benzyl adenine.
14. A process for the preparation of the fertilizer product as claimed in claim 1; said process comprising the following steps:
i. preparing a mixture, at a temperature ranging from 15 oC to 40 oC, by admixing said micronized elemental sulphur in an amount ranging from 70 wt% to 97 wt% of the total weight of the fertilizer product; said at least one dispersing agent in an amount ranging from 0.1 wt% to 1 wt% of the total weight of the fertilizer product; said at least one swelling agent in an amount ranging from 0.1 wt% to 10 wt% of the total weight of the fertilizer product; said at least one binding agent in an amount ranging from 0.3 wt% to 30 wt% of the total weight of the fertilizer product; said at least one sulphur solubilizing microbe having a concentration in the range of 105 cells/ml to 1010 cells/ml; said at least one mineral clay in an amount ranging from 0.5 wt% to 30 wt% of the total weight of the fertilizer product; said at least one plant growth hormone in an amount ranging from 0.001 wt% to 1 wt% of the total weight of the fertilizer product; and water in an amount ranging from 5 wt% to 60 wt% of the total weight of the fertilizer product;
ii. pugging said mixture followed by kneading to obtain dough;
iii. processing said dough to obtain shaped articles, wherein said step of processing is at least one selected from the group consisting of pelletizing, pastilling, extruding, and granulating; and
iv. drying said shaped articles at a temperature ranging from 25 oC to 50 oC to obtain said fertilizer product.