DESC:FIELD
The present disclosure relates to fertilizer products and their process of preparation. Particularly, the present disclosure relates to sulfur based fertilizer products.

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, sulfur, iron, zinc and magnesium.
Sulfur 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 inorganic forms such as sulfate (SO42-). Plants can also use sulfur dioxide (SO2) from the atmosphere. Elemental sulfur can, however, be only absorbed by plants once it is oxidized to sulfate by soil bacteria, namely Thiobacillus, in the presence of moisture/water. Furthermore, elemental sulfur is insoluble in water and in powder form, creates dust which irritates the eyes and is hazardous to health. There is also a possibility that unused sulfur can flow away with water during raining or irrigation and can thus, contaminate the water bodies. Therefore, generally fertilizer products are prepared by mixing elemental sulfur with a carrier medium such as mineral clay, which is used as a soil additive. However, mineral clay can add heavy metals like iron, nickel and the like to the soil. It also contains high sodium levels which lead to an increase in the salinity of the soil. Furthermore, mineral clay has low moisture absorptivity and low disintegration capacity due to which availability of the sulfur to the soil and ultimately its conversion to the required sulfate form is less.
A need, therefore, exists of developing an effective fertilizer product containing elemental sulfur that mitigates the drawbacks associated with the conventional sulfur 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 provide a process for the preparation of a fertilizer product.
It is another object of the present disclosure to provide a fertilizer product prepared by the afore-stated process.
It is still another object of the present disclosure to provide a fertilizer product which is non- hazardous to the user.
It is yet another object of the present disclosure to provide a fertilizer product which is economical, biodegradable, easy to handle and environment friendly.
It is still another object of the present disclosure to provide a fertilizer product which is free from hazardous heavy metals such as iron and nickel.
It is yet another object of the present disclosure to provide a fertilizer product with low sodium content to prevent increasing salinity of soil.
It is still another object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
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 provides a process for the preparation of a fertilizer product comprising preparing a first mixture by admixing ingredients such as elemental sulfur, at least one swelling agent, at least one binding agent, at least one plant growth regulator, optionally, at least one inorganic solid material with water at a temperature ranging from 15 to 40 oC; pugging followed by kneading said first mixture to obtain dough; processing said dough to obtain shaped articles and drying said shaped articles to obtain the fertilizer product. Typically, said step of processing is at least one selected from the group consisting of pelletizing, pastilling, extruding and granulating and said shaped article is at least one selected from the group consisting of pellets, pastilles, extrudates, beads, flakes and granules. In accordance with the present disclosure, the fertilizer product is characterized by moisture content ranging from 0.1 to 1.0 %w/w.

DETAILED DESCRIPTION
In accordance with one aspect of the present disclosure, there is provided a process for the preparation of a fertilizer product. The process initially includes preparing a first mixture by admixing the ingredients in a pre-determined quantity of water at a temperature ranging from 15 to 40 oC. Typically, the ingredients used for the preparation of the mixture include micronized elemental sulfur in an amount ranging from 70 to 98 % of the total weight of the mixture, at least one swelling agent in an amount ranging from 0.1 to 10 % of the total weight of the mixture, at least one binding agent in an amount ranging from 0.5 to 30 % of the total weight of the mixture, at least one plant growth regulator in an amount ranging from 0.005 to 5 % of the total weight of the mixture and optionally at least one inorganic solid material in an amount ranging from 0 to 30% of the total weight of the mixture. Water is used as per requirement and is typically added externally in an amount ranging from 5 to 40 % of the total weight of the mixture. It is a characteristic feature of the present disclosure that inclusion of both the swelling and binding agents enables the admixing at an ambient temperature - a feature which significantly eases the processing and handling and makes the process cost efficient.
In one embodiment, the step of preparation of the first mixture is carried out by incorporating at least one inorganic solid material in an amount ranging from 1 to 30 %w/w and at least one binding agent in an amount ranging from 0.5 to 30 %w/w in liquid molten sulfur being present in an amount ranging from 70 to 98 %w/w of the total weight of the mixture. This step is carried out at a temperature ranging from 119 to 140 oC and is accompanied by stirring to yield the first mixture wherein the inorganic solid material is finely dispersed in molten sulfur.
The resulting first mixture is then pugged and kneaded to obtain dough which is further processed 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 ranging from 25 to 50 oC yield the fertilizer product of the present disclosure. Typically, 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.
The process of the present disclosure is designed as presented herein above to achieve some specific objectives. The processing steps of pelletizing, pastilling, extruding and granulating are purposefully included to prepare a fertilizer product such that its constituent units (shaped articles) have definitive macromolecular dimensions. This is a special feature of the product of the present disclosure which is associated with plentiful advantages such as obviation of the problems accompanying sulfur dust, increase in the water holding capacity and slow release of the ingredients such as potassium, nitrogen, water and plant growth regulators into the soil; 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 and can be decomposed on exposure to elevated temperatures (above 100 oC) during the process of preparation. Therefore, processes which can be carried out at ambient temperatures, such as the present process, are favored.
In accordance with another aspect, the present disclosure provides a fertilizer product prepared from the afore-stated process. The product is in the form of shaped articles selected from the group consisting of pellets, pastilles, extrudates, beads, flakes and granules, having size ranging from 1.5 to 6 mm. Typically, the fertilizer product has moisture content ranging from 0.1 to 1.0 %w/w . The product includes the ingredients provided herein below.
Micronized elemental sulfur is present in an amount ranging from 70 to 98 % of the total weight of the first mixture, preferably from 87 to 98 %w/w. Sulfur being an extremely important nutrient for plants, demonstrates a wide array of activities. Sulfur enhances availability of the necessary plant nutrients in the soil, which improves the quality and yield of the agricultural crops. Further, sulfur is a vital element necessary for the synthesis of entities such as sulfur-containing amino acids and proteins, coenzyme A, biotin, thiamine, glutathione, chlorophyll, lipids and volatile oils. Furthermore, sulfur in its elemental form, acts as a pesticide and fungicide against certain soil pests and micro-organisms. The sulfur included in the present product is of particle size ranging from 10 µm to 250 µm. In one embodiment, the elemental sulfur is of more than 99% purity, obtained from Claus process post hydrodesulphurization in oil refinery.
The product contains at least one swelling agent in an amount ranging from 0.1 to 10 % of the total weight of the first mixture, preferably from 1 to 10 %w/w and is at least one 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. Upon absorption of water, the product expands leading to breaking of pellets, extrudates and the like to release fine sulfur particles along with other ingredients such as the plant growth regulators across a very wide perimeter. In one embodiment, after swelling, the elemental sulfur present in the fertilizer product disperses into fine particles having a diameter less than 30 µm. As a virtue of the size reduction of the sulfur particles, they get easily oxidized into the sulfate form.
2 S + 3 O2 + 2 H2O ? 2 H2SO4

It is significant to note that fertilizer products which have high sulfur content and low swelling agent content have good applicability in lands with high salinity and 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 low sulfur and high swelling agent content have a high water holding capacity and are thus useful for the regions facing water scarcity.

Binding agent(s) are included in the present product to facilitate effective binding between micronized elemental sulfur and the other ingredients in order to form an aesthetic and uniform fertilizer product. The product of the present disclosure contains at least one binding agent in an amount ranging from 0.5 to 30 % of the total weight of the first mixture, preferably from 1 to 13 %w/w and 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.
The product of the present disclosure also contains at least one plant growth regulator in an amount ranging from 0.005 to 5 % of the total weight of the first mixture, preferably from 0.005 to 1 %w/w and is selected from the group consisting of auxins, gibberellins, cytokinins and abscisic acid (ABA). More specifically, the plant growth regulator is at least one selected from the group consisting of indole-3-acetic acid (IAA), gibberellic acid (GA) and 6-benzyl adenine (BA).
At least one inorganic solid material is present in the product of the present disclosure in an amount ranging from 0 to 30% of the total weight of the first mixture, preferably from 0 to 10 %w/w. The inorganic solid material is selected from the group consisting of zeolites, clays, aluminosilicates and molecular sieve; more specifically, from the group consisting of zeolite A, zeolite X, ZSM-5, clinoptilolite, phillipsite, aluminum phosphate (AlPO4) zeolites, silicon aluminum phosphate (SAPO4) zeolites, montmorillonite, kaolinite, hectorite, attapulgite, mordenite, molecular sieve MS-3A, molecular sieve 4A and spent Fluid catalytic cracking (FCC) catalyst. In one embodiment, the inorganic solid material of the present disclosure is nanoporous. In one embodiment, the inorganic materials are molecular sieves used for air drying and solvent drying in petrochemical or refining complex and can be used in powdered or granular form. Inclusion of the nanoporous inorganic solids is advantageous as these substances have a tendency to trap the heavy metal ions present in soil, so that the heavy metals do not get accumulated in the plants. Furthermore, their high water adsorption capacities in the dehydrated state and their high ion-exchange capacities make many natural zeolites effective carriers of herbicides, fungicides, and pesticides. Still further, the zeolites are also efficient in modifying the soil texture - removing the alkalinity of the soil due to their ion exchange capability. Zeolites upon mixing with soil help in retaining its moisture and maintaining sufficient aeration which enhances the crop yield. The inorganic solid material of the present disclosure also contains plant nutrients absorbed into their framework. Upon their introduction into the soil, the inorganic solid material releases the nutrients as a result of which the crops are immensely benefited. The plant nutrient present in the inorganic solids is at least one selected from the group consisting of K, Mg, Ca, Fe, Mn, Mo, PO4, NH3, Zn, Cu, B, and Co.
Water is included in the product to facilitate formation of dough. Typically, it is present in an amount ranging from 5 to 40 % of the total weight of the first mixture, preferably from 10 to 33 %w/w.
In one embodiment, the fertilizer product of the present disclosure consists of elemental sulfur, at least one swelling agent, at least one binding agent, at least one plant growth regulator and water. In another embodiment, the fertilizer product of the present disclosure consists of elemental sulfur, at least one swelling agent, at least one binding agent, at least one plant growth regulator, at least one inorganic solid material and water.
The effectiveness of the fertilizer product of the present disclosure lies in its preparation in the form of shapes such as pellets, pastilles and the like and employment of the principle of water imbibition. The swelling agents upon absorption of water make the shaped articles swell up to a great extent; thereby resulting in dispersion of very fine sulfur particles. As the rate of oxidation of fine particles is greater than that of larger particles, more quantity of sulfur is available to plants in their desired form, thereby improving the quality and yield of the plants. Furthermore, the pH of the product upon dispersion into soil ranges from 7.4 to 8.5, which is suitable for plants, soil and soil microbes. The fertilizer product of the present disclosure does not use additives such as fillers, surfactants, wetting agents and the like which is in contrast to the conventional products. The characteristic combination of ingredients, especially inclusion of both the swelling and binding agents leads to the fertilizer products having optimum crushing strength, swelling and dispersion indices. Typically, the fertilizer product of the present disclosure has mechanical strength in the range of 1.5 to 6 Kgf which is essential to give a dust-free product with the required dispersity.
The present disclosure will now be discussed in the light of the following non-limiting embodiments:
Example 1: Preparation of the fertilizer product - Process Optimization
Example 1A: Sulfur + Binding agent
70 g of micronized elemental sulfur was mixed with 30 g of carboxymethyl cellulose (CMC) as a binding agent. A sufficient quantity of water was added on dry weight basis to form the first mixture. The first mixture was pugged and kneaded and half of the resultant dough was mechanically converted into extrudates in the size range (diameter x length) of 1.5 x 5 - 7 mm using an extruder. The remaining half was agglomerated into spherical beads of the size of 3 to 4 mm using a pan or drum granulator. The formed extrudates and spherical beads were air dried to have less than 0.5 wt% of moisture content on dry weight basis. Methods of drying of formed bodies included vacuum or microwave drying – methods apparent to those skilled in the art.
Swelling and dispersion properties of the formed extrudates and beads were measured by taking 10 ml of formed extrudates in a 100 ml measuring cylinder filled with water. After 60 minutes, the volume of the formed extrudates was found to increase by 70% and completely disperse into less than 30 micron size after 20 hours. The extrudates of the present disclosure had a crushing strength of 4.4 Kgf.
Some additional trials were conducted by keeping the rest of the procedure same as mentioned in Example 1A. The results obtained are provided herein below in Table 1.
Table 1
Ex./ Trial No. Ingredient in the product Product properties
Sulfur (g) Binding agent
Size
(mm) Moisture content
(%) Crushing strength (Kgf) % Swelling Dispersion time (in hrs)
Binder Quantity (g)
(Ex. 1)
Trial 1 70 CMC 30 Extrudate: 1.5 x 5-7
Bead: 3 to 4
<0.5 4.4 70 20
2 90 CMC 10 Extrudate: 1.5 x 5-6
Bead: 3 to 4 <0.5 3.1 40 20
3 95 CMC 5 Extrudate: 1.5 x 5-6
Bead: 3 to 4 <0.5 2.8 33 20
4 98 CMC 2 Extrudate: 1.5 x 5-7 Bead: 3 to 4 <0.5 1.8 34 20
5 99.5 CMC 0.5 Extrudate: 1.5 x 5-6
Bead: 3 to 4 <0.5 1.5 25 20
6 98 HPC 2 Extrudate:
1.5 x 4-5
Bead: 3 to 4 <0.5 1.5 5 20
7 90 Corn Starch 10 Extrudate:
1.5 x 5-6
Bead: 3 to 4 <0.5 1.6 11 20
CMC: carboxy methyl cellulose; HPC: hydroxy propyl cellulose
Inference: The results indicate that when the product contains sulfur and binding agent, the crushing strength ranges from 1.5 to 4.5 Kgf; the % swelling ranges from 5 to 70 and the dispersion time is 20 hours.
Example 1B: Sulfur + Binding agent + Swelling agent
97 g of micronized elemental sulfur was mixed with 2 g of carboxymethyl cellulose as a binding agent and 1 g potassium salt of polyacrylamide grafted cellulose as a swelling agent. A sufficient quantity of water was added on dry weight basis to obtain the first mixture. The mixture was pugged and kneaded and half of the resultant dough was mechanically converted into extrudates in the size range (diameter x length) of 1.5 x 4-7 mm using an extruder. The remaining half was agglomerated into spherical beads of the size of 3 to 4 mm using a pan or drum granulator. The formed extrudates and spherical beads were air dried to have less than 0.5 wt% of moisture content on dry weight basis. Methods of drying of formed bodies included vacuum or microwave drying – methods apparent to those skilled in the art.
Swelling and dispersion properties of the formed extrudates and beads were measured by taking 10 ml of formed extrudates in a 100 ml measuring cylinder filled with water. After 60 minutes, the volume of the formed extrudates was found to increase by 89% and completely disperse into less than 30 micron size after 12 hours. The extrudates of the present disclosure had a crushing strength of 1.9 Kgf.
Some additional trials were conducted by keeping the rest of the procedure same as mentioned in Example 1B. The results obtained are provided herein below in Table 2.
Table 2
Ex./ Trial No Ingredient in the product Product properties
Sulfur (g) Binding agent (g) Swelling agent (g) Size
(mm) Moisture content
(%) Crushing strength (Kgf) % Swelling Dispersion time (in hrs)
(Ex. 2)
Trial 8 97 CMC (2) Poly A(1) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.9 89 12
9 97 CMC (2) Poly B (1) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.8 92 6
10 97 EC (2) Poly A (1) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.2 70 6
11 97 CMC (2) Poly A(0.5) + Poly B (0.5) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.9 90 10
12 97 HPMC (2) Poly A (1) Extrudate: 1.5 x 4-6
Bead: 3 to 4 <0.5 1.8 33 12
13 89 Corn Starch (10) Poly A (1) Extrudate: 3.0 x 5-7
Bead: 3 to 4 <0.5 3.2 56 20
14 97 PVA (1) Poly A (2) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.8 40 20
15 97 PVA (0.5) + CMC (1.5) Poly A (1) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.9 60 20
16 97 PVA (0.5) + CMC (1.5) Poly B (1) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.9 80 16
17 97 HPMC (2) Poly B (1) Extrudate: 1.5 x 4-6
Bead: 3 to 4 <0.5 1.8 90 12
18 88 CMC (10) Poly B (2) Extrudate: 6.0 x 5-7
Bead: 3 to 4 <0.5 4.4 200 4
19 88 CMC (2) Poly A (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.1 250 4
Poly A: Potassium salt of polyacrylamide grafted cellulose; Poly B: Polyacrylic Acid; CMC: Carboxy methyl cellulose; EC: Ethyl cellulose; HPMC: Hydroxy propyl methylcellulose; PVA: Polyvinyl alcohol
Inference: The results indicate that when the product contains sulfur, binding agent and swelling agent the crushing strength ranges from 1.5 to 4.5 Kgf; the % swelling ranges from 33 to 250 and the dispersion time ranges from 4 to 20 hours.
Example 1C: Sulfur + Binding agent + Swelling agent + Plant Growth Regulators
96 g of micronized elemental sulfur was mixed with 1.995 g carboxymethyl cellulose as a binding agent, 2 g potassium salt of polyacrylamide grafted cellulose as a swelling agent and 0.005 g of GA as a plant growth hormone. A sufficient quantity of water was added on dry weight basis to obtain the first mixture. The mixture was pugged and kneaded and half of the resultant dough was mechanically converted into extrudates in the size range (diameter x length) of 1.5 x 5-7 mm using an extruder. The remaining half was agglomerated into spherical beads of the size of 3 to 4 mm using a pan or drum granulator. The formed extrudates and spherical beads were air dried to have less than 0.5 wt% of moisture content on dry weight basis. Methods of drying of formed bodies included vacuum or microwave drying – methods apparent to those skilled in the art.
Swelling and dispersion properties of the formed extrudates and beads were measured by taking 10 ml of formed extrudates in a 100 ml measuring cylinder filled with water. After 60 minutes, the volume of the formed extrudates was found to increase by 120% and completely disperse into less than 30 micron size after 4 hours. The extrudates of the present disclosure had a crushing strength of 1.8 Kgf.
Some additional trials were conducted by keeping the rest of the procedure same as mentioned in Example 1C. The results obtained are provided herein below in Table 3.

Table 3
Ex./ Trial No Ingredient in the product Product properties
Sulfur (g) Binding agent (g) Swelling agent (g) Plant growth regulators (g) Size
(mm) Moisture content
(%) Crushing strength (Kgf) % Swelling Dispersion time (in hrs)
(Ex.3) Trial 20 96 CMC (1.995) Poly A(2) GA (0.005) Extrudate: 1.5 x 5-7
Bead: 3 to 4
<0.5 1.8 120 4
21 96 CMC (1.995) Poly A(2) ABA (0.005) Extrudate: 1.5 x 4-6
Bead: 3 to 4 <0.5 1.9 90 4
22 96 CMC (1.995) Poly A(2) BA (0.005) Extrudate: 1.5 x 5-6
Bead: 3 to 4 <0.5 1.8 80 4
23 96 CMC (1.990) Poly A(2) BA (0.005) + GA (0.005) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.8 110 4
24 96 CMC (1.990) Poly A(2) IAA (0.01) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.9 110 4
Poly A: Potassium salt of polyacrylamide grafted cellulose; CMC: Carboxy methyl cellulose; GA: Gibbereillic acid; BA: 6-Benzyl adenine; ABA: Abscisic acid; IAA: Indole-3-acetic acid
Inference: The results indicate that when the product contains sulfur, binding agent, swelling agent and plant growth regulators the crushing strength ranges from 1.5 to 2.0 Kgf; the % swelling ranges from 80 to 120 and the dispersion time is 4 hours.
Example 1D: Sulfur + Binding agent + Swelling agent + Inorganic solids
80 g of micronized elemental sulfur was mixed with 10 g of zeolite X powder, 8 g of potassium salt of polyacrylamide grafted cellulose as a swelling agent and 2 g of carboxymethyl cellulose (CMC) as a binding agent. A sufficient quantity of water was added on dry weight basis to obtain the first mixture. The mixture was pugged and kneaded and half of the resultant dough was mechanically converted into extrudates in the size range (diameter x length) of 1.5 x 5-7 mm of using an extruder. The remaining half was agglomerated into spherical beads of the size of 3 to 4 mm using a pan or drum granulator. The formed extrudates and spherical beads were air dried to have less than 0.5 wt% of moisture content on dry weight basis. Methods of drying of formed bodies included vacuum or microwave drying – methods apparent to those skilled in the art.
Swelling and dispersion properties of the formed extrudates and beads were measured by taking 10 ml of formed extrudates in a 100 ml measuring cylinder filled with water. After 60 minutes, the volume of the formed extrudates was found to increase by 230% and completely disperse into less than 30 micron size after 20 hours. The extrudates of the present disclosure had a crushing strength of 3.5 Kgf.
Some additional trials were conducted by keeping the rest of the procedure same as mentioned in Example 1D. The results obtained are provided herein below in Table 4.
Table 4
Example/ Trial No Ingredient in the product Product properties
Sulfur (g) Binding agent (g) Swelling agent (g) Inorganic solids (g) Size
(mm) Moisture content
(%) Crushing strength (Kgf) % Swelling Dispersion time (in hrs)
(Ex. 4)
Trial 25 80 CMC (2) Poly A (8) Zeolite X (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4
<0.5 3.5 230 20
26 80 CMC (1) + HPMC (1) Poly A (8) ZSM-5 (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4
<0.5 3.3 220 20
27 80 CMC (8) Poly A (2) Zeolite X (10) Extrudate: 6.0 x 5-7
Bead: 3 to 4 <0.5 4.5 280 20
28 80 CMC (2) Poly A (8) ZSM-5 (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 3.2 230 20
29 91 CMC (2) Poly A (2) Clinoptillolite (5) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.4 60 20
30 99.5 CMC (0.3) Poly A (0.1) Phillipsite (0.1) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.5 10 20
31 90 CMC (2) Poly A (2) SAPO4 (6) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.0 58 20
32 92 CMC (2) Poly A (2) AlPO4 (4) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.8 65 20
33 89 CMC (1) - Spent MS (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.8 18 20
34 89 HPMC (1) - Spent MS (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.2 2 20
35 82 Corn starch (9) - Spent MS (9) Extrudate: 3.0 x 5-7
Bead: 3 to 4 <0.5 3.8 11 20
36 88 CMC (1) Poly A (1) Spent MS (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.5 50 20
37 88 Corn starch (1) Poly A (1) Spent MS (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.3 20 20
38 88 PVA (1) Poly A (1) Spent MS (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.2 40 20
39 89 - Poly A (1) Spent MS (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.0 40 20
40 87 - Poly A (3) Spent MS (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.9 105 20
41 85 - Poly A (5) Spent MS (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.8 150 20
42 81 - Poly A (9) Spent MS (10) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 1.6 250 20
43 90.5 EC (1) Poly A (1) Kaoline (7.5) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.9 60 20
Poly A: Potassium salt of polyacrylamide grafted cellulose; CMC: Carboxy methyl cellulose; PVA: Poly vinyl alcohol; HPMC: Hydroxy propylmethyl cellulose; EC: Ethyl cellulose; Spent MS: Spent molecular sieve used for air drying unit
Inference: The results indicate that when the product contains sulfur, binding agent, swelling agent and inorganic solids the crushing strength ranges from 1.5 to 4.5 Kgf; the % swelling ranges from 2 to 280 and the dispersion time is 20 hours.

Example 1E: Sulfur + Binding agent + Swelling agent + Inorganic solids + Plant growth regulators
80 g of micronized elemental sulfur was mixed with 10 g of zeolite A powder, 8 g of potassium salt of polyacrylamide grafted cellulose as a swelling agent, 1.995 g of carboxymethyl cellulose (CMC) as a binding agent and 0.005 g of gibberellic acid (GA) as a plant growth constituent. A sufficient quantity of water was added on dry weight basis to obtain the first mixture. The mixture was pugged and kneaded and half of the resultant dough was mechanically converted into extrudates in the size range (diameter x length) of 1.5 x 5 - 7 mm using an extruder. The remaining half was agglomerated into spherical beads of the size of 3 to 4 mm using a pan or drum granulator. The formed extrudates and spherical beads were air dried to have less than 0.5 wt% of moisture content on dry weight basis. Methods of drying of formed bodies included vacuum or microwave drying – methods apparent to those skilled in the art.
Swelling and dispersion properties of the formed extrudates and beads were measured by taking 10 ml of formed extrudates in a 100 ml measuring cylinder filled with water. After 60 minutes, the volume of the formed extrudates was found to increase by 200% and completely disperse into less than 30 micron size after 20 hours. The extrudates of the present disclosure had a crushing strength of 2.1 Kgf.
Some additional trials were conducted by keeping the rest of the procedure same as mentioned in Example 1E. The results obtained are provided herein below in Table 5.

Table 5
Example/ Trial No Ingredient in the product Product properties
Sulfur (g) Binding agent (g) Swelling agent (g) Inorganic solids (g) Plant growth regulators (g) Size
(mm) Moisture content
(%) Crushing strength (Kgf) % Swelling Dispersion time (in hrs)
(Ex. 5)
Trial 44 80 CMC (1.995) Poly A(8) Zeolite A (10) GA (0.005) Extrudate: 1.5 x 5-7
Bead: 3 to 4
<0.5 2.1 200 20
45 80 CMC (1.995) Poly A(8) Spent MS (10) ABA (0.005) Extrudate: 1.5 x 5-6
Bead: 3 to 4 <0.5 3.2 240 20
46 80 CMC (1.995) Poly A(8) Spent zeolite X (10) BA (0.005) Extrudate: 3.0 x 5-7
Bead: 3 to 4 <0.5 4.4 220 20
47 80 CMC (1.990) Poly A(2) ZSM-5 (10) BA (0.005) + GA (0.005) Extrudate: 1.5 x 5-7
Bead: 3 to 4 <0.5 2.9 220 20
Poly A: Potassium salt of polyacrylamide grafted cellulose; CMC: Carboxy methyl cellulose; GA: Gibbereillic acid; BA: 6-benzyl adenine; ABA: abscisic acid; Spent MS: Spent molecular sieve used for air drying unit
Inference: The results indicate that when the product contains sulfur, binding agent, swelling agent, inorganic solids and plant growth regulators the crushing strength ranges from 2.1 to 4.5 Kgf; the % swelling ranges from 2 to 280 and the dispersion time is 20 hours.
Conclusion: After studying the inferences of all the examples it is apparent that the products of Examples 1C and 1E have the most desirable combination of properties such as crushing strength, % swelling and dispersion time.

Example 2: Preparation of the fertilizer product – another embodiment
90 g of elemental sulfur was melted at a temperature ranging from 119-140 oC and 10 g of spent FCC was added to the molten sulfur slurry. The molten mass was processed to form pastilles and granules of size ranging from 3 to 5 mm by dropping the molten mass on a cold surface or by quenching in water.
Swelling and dispersion properties of the shaped articles were measured by taking 10 ml of the shaped articles in a 100 ml measuring cylinder filled with water. After 60 minutes, the volume of the formed extrudates was found to increase by 5% and they were found to completely disperse into less than 30 micron size after 72 hours. The shaped articles of the present disclosure had a crushing strength of 3.0 Kgf.
Some additional trials were conducted by keeping the rest of the procedure same as mentioned in Example 2. The results obtained are provided herein below in Table 6.
Table 6
Example/ Trial No Ingredient in the product Product properties
Sulfur (g) Binding agent (g) Spent FCC (g) Inorganic solids (g) Crushing strength (Kgf) % Swelling Dispersion time (in hrs)
(Ex. 6)
Trial 48 90 0 10 0 3.0 5 72
49 80 CMC (0.5) 10 Zeolite X (9.5) 4.2 7 70
50 70 0 20 Attapulgite (10) 4.9 6 70
51 80 HPMC (0.1) 9.9 Spent MS (10) 4.2 5 70
CMC: Carboxy methyl cellulose; HPMC: Hydroxy propylmethyl cellulose; Spent MS: Spent molecular sieve used for air drying unit; Spent FCC: Spent fluid catalytic cracking unit equilibrium catalyst
Inference: The results indicate that when the product contains sulfur, binding agent, spent catalyst and inorganic solids, the crushing strength ranges from 3.0 to 5.0 Kgf; the % swelling ranges from 5 to 7 and the dispersion time ranges from 70 to 72 hours.

Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE
• The fertilizer product is of multi-functional nature as it has higher sulfur content, higher water holding capacities and slow release of plant nutrients into the soil.
• The present disclosure provides a dust-free, economical, toxic metal-free elemental sulfur containing fertilizer product as the feed for horticultural purposes.
• The present disclosure not only provides a fertilizer product containing higher percentage of sulfur for plant nourishment, but also a product for the protection of plants by exhibiting antifungal activities against certain soil pests and microorganisms.
• The present disclosure provides a fertilizer product having lower Na content and pH in the range of 7.5 to 8.5 to lower the salinity of the soil.
• The present disclosure also provides a simple, effective and economic process for the preparation of a fertilizer product with desired mechanical strength.
• The process of preparing the fertilizer product avoids the steps of admixing of fertilizer components in slurry form.
• The present disclosure provides an effective way of reutilizing spent catalysts such as molecular sieves, Fluid catalytic cracking (FCC) catalyst and the like.

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 invention to achieve one or more of the desired objects or results.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention and the claims unless there is a statement in the specification to the contrary.

While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications in the process or compound or formulation or combination of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention. ,CLAIMS:1. A process for the preparation of a fertilizer product; said process comprising the following steps:
i. preparing a first mixture at a temperature ranging from 15 to 40 oC by admixing elemental sulfur in an amount ranging from 70 to 98 % of the total weight of the mixture, at least one swelling agent in an amount ranging from 0.1 to 10 % of the total weight of the mixture, at least one binding agent in an amount ranging from 0.5 to 30 % of the total weight of the mixture, at least one plant growth regulator in an amount ranging from 0.005 to 5 % of the total weight of the mixture, water in an amount ranging from 5 to 40 % of the total weight of the mixture and at least one inorganic solid material in an amount ranging from 0 to 30% of the total weight of the mixture;
ii. pugging followed by kneading said mixture 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 to 50 oC to obtain the fertilizer product,
wherein and said shaped article is at least one selected from the group consisting of pellets, pastilles, extrudates, beads, flakes and granules.
2. A fertilizer product comprising:
i. elemental sulfur having particle size ranging from 10 to 250 µm, in an amount ranging from 70 to 98 % of the total weight of the first mixture;
ii. at least one swelling agent in an amount ranging from 0.1 to 10 % of the total weight of the first mixture;
iii. at least one binding agent in an amount ranging from 0.5 to 30 % of the total weight of the first mixture;
iv. at least one plant growth regulator in an amount ranging from 0.005 to 5 % of the total weight of the first mixture;
v. water in an amount ranging from 5 to 40 % of the total weight of the first mixture; and
vi. optionally, at least one inorganic solid material in an amount ranging from 0 to 30 % of the total weight of the first mixture,
wherein said product is in the form of shaped articles selected from the group consisting of pellets, pastilles, extrudates, beads, flakes and granules.
3. The fertilizer product as claimed in claim 2, having a crushing strength ranging from 1.5 to 6.0 Kgf, % swelling ranging from 2 to 280 and dispersion time ranging from 4 to 20 hours.
4. The fertilizer product as claimed in claim 2, characterized by moisture content ranging from 0.1 to 1.0 %w/w.
5. The fertilizer product as claimed in claim 2, wherein said shaped articles have a size ranging from 1.5 to 6 mm.
6. The fertilizer product as claimed in claim 2, wherein said swelling agent is at least one selected from the group consisting of polyacrylic acid, polyacrylamide, cellulose grafted polyacrylamide, potassium salt of polyacrylamide and starch grafted polyacrylamide.
7. The fertilizer product as claimed in claim 2, wherein said binding agent is at least one 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
8. The fertilizer product as claimed in claim 2, wherein said plant growth regulator is at least one selected from the group consisting of auxins, gibberellins, cytokinins and abscisic acid (ABA).
9. The fertilizer product as claimed in claim 8, wherein said plant growth regulator is at least one selected from the group consisting of indole-3-acetic acid (IAA), gibberellic acid (GA) and 6-benzyl adenine (BA).
10. The fertilizer product as claimed in claim 2, wherein said inorganic solid material is at least one selected from the group consisting of zeolites, clays, aluminosilicates and molecular sieves.
11. The fertilizer product as claimed in claim 2, wherein said inorganic solid material comprises at least one plant nutrient selected from the group consisting of K, Mg, Ca, Fe, Mn, Mo, PO4, NH3, Zn, Cu, B, and Co.