Claims:1. A composite binder of Formula (I) -
(X1) n-(X2)n-1-X3 ----- OH-Y
OH-Y
Formula (I)
wherein X1 is selected from a group comprising glucose, galactose and mannose or any combination thereof;

wherein X2 is ;

wherein X3 is selected from a group comprising ;

and ;

wherein Y is selected from a group comprising Aluminum and Silicon; and wherein n ranges from about 40 to about 3000.
2. The composite binder as claimed in claim 1, wherein X1 is bound to X2 through terminal oxygen moiety of X1 through an ether linkage; and wherein carbonyl oxygen of X2 and X3 interact with the hydroxy group of the OH-Y moiety through hydrogen bond.
3. The composite binder as claimed in claim 1, wherein the composite binder of Formula (I) is

wherein n ranges from about 40 to about 3000.
4. The composite binder as claimed in any of the above claims, wherein (X1)n is selected from a group comprising starch, dextrin and guar gum or any combination thereof; and wherein n ranges from about 40 to about 3000.
5. The composite binder as claimed in claim 1, wherein the composite binder of Formula (I) is

wherein n ranges from about 40 to about 3000.
6. A method of preparing the composite binder as claimed in claim 1, comprising-
contacting a polysaccharide with an amide to form a reaction mixture;
adding polymerization initiator(s) to the reaction mixture to obtain a grafted polymer; and
contacting the grafted polymer with filler(s) to obtain the composite binder.
7. The method as claimed in claim 6, wherein the polysaccharide is selected from a group comprising starch, dextrin and guar gum or any combination thereof; wherein the amide is acrylamide.
8. The method as claimed in claim 6, wherein the polymerization initiator(s) is selected from a group comprising potassium persulfate and ammonium persulfate or a combination thereof; wherein the filler(s) is selected from a group comprising inorganic clays; and wherein the inorganic clay is bentonite.
9. The method as claimed in claim 6, wherein the polysaccharide and amide are contacted at a ratio ranging from about 1:1 to about 1:5.
10. The method as claimed in claim 6, wherein the polysaccharide and amide are contacted at a temperature ranging from about 70°C to about 80°C and mixed for a duration ranging from about 20 minutes to about 30 minutes.
11. The method as claimed in claim 6, wherein the polymerization initiator(s) is added to the reaction mixture at a ratio ranging from about 1:500 to about 1:400.
12. The method as claimed in claim 6, wherein the polymerization initiator(s) is added to the reaction mixture at a temperature ranging from about 70°C to about 80°C and subjected to mixing for a duration ranging from about 5 minutes to about 15 minutes.
13. The method as claimed in claim 6, wherein the grafted polymer is contacted with the filler(s) at a ratio ranging from about 12:1 to about 60:1; wherein the contacting is at a temperature ranging from about 70°C to about 80°C; wherein the mixture subjected to mixing for a duration ranging from about 1 hour to about 1.5 hours and allowed to cool down to room temperature.
14. The method as claimed in claim 6, further comprising washing the composite binder with solvent; and optionally subjecting the washed composite binder to drying.
15. The method as claimed in claim 14, wherein the solvent is selected from a group comprising acetone and ethanol or a combination thereof; and wherein the drying is conducted at a temperature ranging from about 50°C to 100°C for about 8 hours to about 10 hours.
16. A compound binder comprising the composite binder as claimed in claim 1, secondary filler(s) and secondary binder(s).
17. The compound binder as claimed in claim 16, wherein the secondary filler(s) is selected from a group comprising inorganic clays; wherein the inorganic clay is bentonite.
18. The compound binder as claimed in claim 16, the secondary binder(s) is selected from a group comprising cement and blast furnace slag or a combination thereof.
19. The compound binder as claimed in claim 16, wherein the composite binder, the secondary filler(s) and the secondary binder(s) are present at a ratio ranging from about 1:1:2 to about 2:4:4.
20. A method of preparing the compound binder as claimed in claim 16, said method comprising mixing the composite binder as claimed in claim 1 with the secondary filler(s) and the secondary binder(s).
21. The method as claimed in claim 20, wherein the mixing is achieved by method selected from a group comprising simple mixing, mechanical agitation, milling and blending in a mortar and pestle or any combination thereof; and wherein the mixing is carried out at a temperature ranging from about 24°C to about 27°C.
22. A kit comprising components selected from a group comprising coke fines, the binder as claimed in claim 1, the secondary filler(s), the secondary binder(s) and the compound binder as claimed in claim 16 or any combination thereof along with an instruction manual.
23. Coke briquette comprising coke fines and the composite binder as claimed in claim 1 or the compound binder as claimed in claim 16.
24. The coke briquette as claimed in claim 23, wherein the coke fines and the composite binder as claimed in claim 1 or the compound binder as claimed in claim 16 are present at a ratio ranging from about 19:1 to about 9:1.
25. The coke briquette as claimed in claim 24, wherein the coke fines and the composite binder as claimed in claim 1 are present at a ratio ranging from about 49:1 to about 9:1.
26. The coke briquette as claimed in claim 24, wherein the coke fines and the compound binder as claimed in claim 16 are present at a ratio ranging from about 19:1 to about 8:2.
27. The coke briquette as claimed in claim 23, wherein the briquette has CCS ranging from about 900 kgf/briquette to about 982 kgf/briquette.
28. A method of preparing the coke briquette as claimed in claim 23 comprising
mixing coke fines with the composite binder as claimed in claim 1 or the compound binder as claimed in claim 16 to obtain a mixture; and
subjecting the mixture to compression to obtain the coke briquette.
29. The method as claimed in claim 28, wherein the coke fines have particle size ranging from about 0.045 mm to about 8 mm; and wherein moisture content of the coke fines ranges from about 2% to about 4%.
30. The method as claimed in claim 28, wherein the mixing is achieved by method selected from a group comprising simple mixing, mechanical agitation, milling and blending in a mortar and pestle or any combination thereof; wherein the mixing is at a temperature ranging from about 24°C to about 27°C for about 20 minutes to about 30 minutes; and wherein the mixing is performed in an environment having moisture content ranging from about 3% to about 10%.
31. The method as claimed in claim 28, wherein the compression is performed in a hydraulic press.
32. The method as claimed in claim 28, wherein the coke briquette is further subjected to curing; wherein the curing is performed at ambient temperature for about 70 hours to about 90 hours.
Dated this 17th day of February 2021
DURGESH MUKHARYA
IN/PA No. 1541
Of K&S Partners
Agent for the Applicant
To:
The Controller of Patents,
The Patent Office, at: Kolkata , Description:FIELD OF THE INVENTION:
The present disclosure relates to the field of material science and metallurgy. The disclosure provides a composite binder of Formula (I) that aids in efficient formation of coke briquettes from coke fines. The composite binder enables efficient utilization of the coke fines by their reformulation into coke briquettes and confers to the coke briquettes high thermal stability. The disclosure further provides a compound binder comprising the composite binder of Formula (I) with a secondary filler and a secondary binder. Said compound binder also aids in formation of coke briquettes from coke fines. Further provided herein are coke briquettes comprising coke fines and the composite binder of Formula (I) or the compound binder as described above.

BACKGROUND AND PRIOR ART OF THE INVENTION
Ferroalloys are designed to boost steel and alloys properties by adding specific alloys in suitable amounts in the most feasible technological and economic way. The manufacturing processes of ferro-alloy are extremely energy and coke-intensive processes. Conventionally, ULP coke and Nut coke are the prime material used as reductant for Ferro Alloy production. Considering the cost perspective for the current state of art, 18 % of the total cost comes through reductant. Owing to the demand of Ferro Alloys application in steel and allied industry, coke holds a good market share in the world.
During the process of carbonization of coke and further size operations leads to three different grades of Coke such as blast furnace coke, nut coke, and coke breeze. Coke Breeze is a valuable fuel that can be used as various energy application such as power plant, heating purpose and metallurgical operation. Coke dust is also generated during storage, handling and processing. The potential value of these fines/dust is yet to be realized. Agglomeration of such fines/dust to a definite shape can be utilized to meet the desired purpose. Establishing a cost-effective briquetting process is however a challenging task.
GB1181752A describes briquetting of fine coke or similar fine carbonaceous material by mixing with oil-in-water emulsion containing a water-soluble adhesive further added with binding agent coke and then heating at a temperature 330 0C to 2800 0C for 1.5 hours to 4 hours.
Kural et. al describes APP, a binder for briquetting lignites. APP is applied to coal as a binder. The APP is a polypropylene based emulsion. Emulsions in water are described to have been prepared with various modified atactic polypropylenes, containing about 50 % solids, followed by modification after oxidation. The application however appears to be restricted to household purposes.
Further disclosures of binder compositions in the art are faced with challenges such as cost efficiency, thermal stability, control over adhesiveness and further, scalability of the briquetting application. Addressing said drawbacks in the art, the present disclosure provides a composite binder and a compound binder comprising the composite binder, both of which are products of a simplistic synthesis process and provide excellent control over the thermal stability and adhesive nature of the material.
SUMMARY OF THE DISCLOSURE
Accordingly, to solve the above identified problems in the art, the present invention provides a composite binder of Formula (I) -
(X1) n-(X2)n-1-X3 ----- OH-Y
OH-Y
Formula (I)
wherein X1 is selected from a group comprising glucose, galactose and mannose or any combination thereof;

wherein X2 is ;

wherein X3 is selected from a group comprising ;

and ;

wherein Y is selected from a group comprising Aluminum and Silicon; and wherein n ranges from about 40 to about 3000.
In some embodiments, X1 is bound to X2 through terminal oxygen moiety of X1 through an ether linkage; and wherein carbonyl oxygen of X2 and X3 interact with the hydroxy group of the OH-Y moiety through hydrogen bond.
In exemplary embodiments, the composite binder of Formula (I) is

wherein n ranges from about 40 to about 3000.
Further provided herein is a method of preparing the composite binder as described above, comprising-
contacting a polysaccharide with an amide to form a reaction mixture;
adding polymerization initiator(s) to the reaction mixture to obtain a grafted polymer; and
contacting the grafted polymer with filler(s) to obtain the composite binder.

In some embodiments, in the above method, the polysaccharide is selected from a group comprising starch, dextrin and guar gum or any combination thereof; the amide is acrylamide; and the polymerization initiator(s) is selected from a group comprising potassium persulfate and ammonium persulfate or a combination thereof; and the filler(s) is selected from inorganic clays such as but not limited to bentonite.
Further provided in the present disclosure is a compound binder comprising the above-described composite binder, secondary filler(s) and secondary binder(s).
In some embodiments, the secondary filler(s) is selected from inorganic clays such as but not limited to bentonite; and the secondary binder(s) is selected from a group comprising cement and blast furnace slag or a combination thereof. In some embodiments, the composite binder, the secondary filler(s) and the secondary binder(s) are present in the compound binder at a ratio ranging from about 1:1:2 to about 2:4:4.
The present disclosure further provides a method of preparing the aforesaid compound binder, said method comprising mixing the composite binder as claimed in claim 1 with the secondary filler(s) and the secondary binder(s).
Further provided herein is a kit comprising components selected from a group comprising coke fines, the composite binder as described above, the secondary filler(s), the secondary binder(s) and the aforesaid compound binder or any combination thereof along with an instruction manual.
The present disclosure further envisages cokes briquettes comprising coke fines and the composite binder or the compound binder as described above.
In order to enable a skilled artisan to prepare the aforesaid briquette, the present disclosure also provides a method of preparing the aforesaid coke briquette comprising
mixing coke fines with the composite binder or the compound binder described above to obtain a mixture; and
subjecting the mixture to compression to obtain the coke briquette.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure where:
FIG 1. depicts a schematic representation of synthesis of the composite binder of Formula (I) (starch-graft-polyacrylamide and bentonite-based hydrogel binder (SGPBH)).
FIG 2. depicts percentage versus monomer ratio of the composite binder.
FIG 3. depicts size analysis of coke dust employed for preparing the coke briquettes of the present disclosure.
FIG 4. depicts results of Fourier-Transform Infrared Spectroscopy (FTIR) analysis of the composite binder.
FIG 5. depicts Scanning Electron Microscope (SEM) micrograph of the composite binder.
FIG 6. depicts Energy-Dispersive X-Ray (EDAX) image of the composite binder.
FIG 7. depicts a) physical appearance of the composite binder and the coke briquette comprising coke fines and the compound binder and b) Cold Crushing Strength (CCS) graph of coke briquette comprising compound binder.
FIG 8. depicts results of thermogravimetric analysis (TGA) of the composite binder and coke briquette of the present disclosure.
FIG 9. depicts mechanism involved in the process of preparing coke briquette using the compound binder of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
Addressing the requirements in the art, the present disclosure provides a composite binder of Formula (I), a compound binder comprising the composite binder in combination with a secondary filler(s) and a secondary binder(s) and methods to prepare the same. Further provided herein is the application of the composite binder and the compound binder in the preparation of coke briquettes. However, before describing the invention in detail, provided below are definitions of some terms used throughout the present disclosure.
The terms ‘composite binder’ and ‘binder’ used interchangeably throughout the present disclosure refer to the compound of Formula (I). Said ‘composite binder’ or ‘binder’ is essentially a hybrid polymer which comprises an amide grafted polysaccharide into which filler(s) is incorporated. Said compound of Formula (I) is a biopolymer-based compound. Thus, the terms ‘hybrid polymer’, ‘composite binder’ and ‘binder’ used interchangeably in the context of the present disclosure, refer to the biopolymer based composite binder of Formula (I).
As used herein, the term ‘compound binder’ refers to a compound binder composed of the composite binder and additional/secondary binder(s) and filler(s).
The term ‘coke fines’ envisages all possible forms of low ash metallurgical or unutilized coke of varied grain size, including not limited to forms such as coke fines, coke dust, coke breeze, with no particular restriction on source.
As used throughout the present disclosure, the phrase ‘grafted co-polymer’ and different obvious variations thereof refer to the backbone of the composite binder characterized by a polysaccharide chain onto which amide monomers are grafted. The amide monomers are covalently bonded and polymerized as a side chain of the polysaccharide chain.
With respect to the use of various well-known components in the present disclosure whose concentrations are not particularly defined herein, said components are deemed to be used in concentrations that are well known to a person skilled in the art in the context of material science and/or metallurgical applications such as those described in the present disclosure.

As used throughout the present disclosure, ranges are a shorthand for describing each and every value within the range. Any value within the range can be selected as the terminus of the range.
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. 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. The use of the expression ‘about’ refers to values ±20%, ±10%, ±5%, ±4% ±3% ±2% or ±1% of the values defined immediately following said term. Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” wherever used, 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 present disclosure provides a composite binder of formula (I) –
(X1) n-(X2)n-1-X3 ----- OH-Y
OH-Y
wherein X1 is selected from a group comprising glucose, galactose and mannose or any combination thereof;
wherein X2 is ;

wherein X3 is selected from a group comprising ,

and ;
wherein Y is selected from a group comprising Aluminum and Silicon; and wherein n ranges from about 40 to about 3000.
In some embodiments, X1 is selected from a group comprising alpha D-glucose, beta-D-glucose, alpha-D-mannose, beta-D-mannose and galactose or any combination thereof.
In some embodiments, (X1)n is selected from a group comprising starch, dextrin and guar gum or any combination thereof.
In exemplary embodiments, X1 is glucose and (X1)n is therefore starch. In other words, in the said embodiment, glucose in the above structure is polymerized to yield starch. In said scenario, the starch is composed of polymerized glucose and contains monomeric glucose moieties linked to each other through glycosidic linkage.
In the above defined structure, X1 is bound to X2 through the terminal oxygen moiety of X1 through an ether linkage. Further, the carbonyl oxygen of X2 and X3 interact with the hydroxy group of the OH-Y moiety through hydrogen bond.
The backbone of the composite binder, in preferred embodiments, is a grafted polymer wherein acrylamide is grafted onto starch. In said embodiments, the ratio between the starch and the acrylamide in the grafted polymer backbone of the binder ranges from about 1:5 to about 1:1.
In non-limiting embodiments, the ratio between the starch and the acrylamide in the grafted polymer backbone of the binder is about 1:5, about 1:4.5, about 1:4, about 1:3.5, about 1:3, about 1:2.5, about 1:2, about 1:1.5 or about 1:1. In preferred embodiments, said ratio is about 1:2. The ratio of about 1:2 shows higher grafting efficiency and yields a binder having higher hydrodynamic radius. In some exemplary embodiments, the percentage of grafting of the acrylamide onto the starch polymer ranges from about 50% to about 80%. Figure 2 depicts the analysis of grafting percentage observed in the grafted polymer that forms the backbone of the composite binder.
In exemplary embodiments, the composite binder of Formula (I) is –

wherein n ranges from about 40 to about 3000.
In a further exemplary embodiment, the composite binder of Formula (I) is Starch-g-PAM-Bentonite (SGPBH) –

wherein n ranges from about 40 to about 3000.
In some embodiments, the composite binder as described above finds application in the preparation of coke briquettes from coke fines. Said application has been further elaborated on in later paragraphs.

The present disclosure further provides a method of preparing the composite binder described above, comprising
contacting a polysaccharide with an amide to form a reaction mixture;
adding polymerization initiator(s) to the reaction mixture to obtain a grafted polymer; and
contacting the grafted polymer with filler(s) to obtain the composite binder.
In some embodiments, the polysaccharide is selected from a group comprising starch, dextrin and guar gum or any combination thereof.
In some embodiments, the amide is an alkanamide. In some embodiments, the amide is selected from a group comprising acrylamide and analogues thereof.
In exemplary embodiments, the polysaccharide is starch and the amide is acrylamide.
In some embodiments, the polysaccharide and the amide are mixed at a ratio ranging from about 1:1 to about 1:5 to form the reaction mixture.
In non-limiting embodiments, the polysaccharide and the amide are mixed at a ratio of about 1:5, about 1:4.5, about 1:4, about 1:3.5, about 1:3, about 1:2.5, about 1:2, about 1:1.5 or about 1:1.

In an exemplary embodiment, the polysaccharide and the amide are mixed at a ratio of about 1:2. In an exemplary embodiment, the polysaccharide and the amide are contacted in aqueous medium. In some embodiments, the amide is contacted with an aqueous solution of the polysaccharide, wherein the aqueous polysaccharide solution comprises about 1% to about 5%, preferably about 2% polysaccharide.
Preferably, the polysaccharide is contacted with the amide under nitrogen environment, at a temperature ranging from about 70°C to about 80°C.
In exemplary embodiments, the polysaccharide is contacted with the amide under nitrogen environment at a temperature of about 70°C to about 80°C, preferably about 70°C. The reaction mixture so obtained, in non-limiting embodiments of the present disclosure, is maintained at the above-mentioned conditions for about 20 minutes to about 30 minutes before adding the polymerization initiator(s). In some embodiments, the reaction mixture is subjected to agitation by use of a magnetic stirrer.
In order to facilitate grafting of the amide monomers onto the polysaccharide and form a grafted polymer backbone, the above mixture of polysaccharide and amide is contacted with polymerization initiator(s).
In some embodiments, the polymerization initiator(s) is selected from a group comprising potassium persulfate and ammonium persulfate or a combination thereof. In an exemplary embodiment, the initiator is potassium persulfate, wherein during reaction, persulfate gets decomposed to yield sulphate radical along with free radical species.
The polymerization initiator(s) is added to the mixture of polysaccharide and amide at a ratio of about 1:500 to about 1:400.
In some embodiments, the polymerization initiator(s) is added to the reaction mixture at a temperature ranging from about 70°C to about 80°C and subjected to mixing for a duration ranging from about 5 minutes to about 15 minutes.
Post addition of the polymerization initiator(s), a viscous gel formation takes place which indicates the start of polymerization reaction that yields the grafted polymer. Polymerization of the amide takes place in the presence of the initiator wherein a free radical mechanism pathway is responsible for the polymerization. Said polymer of the amide forms side chains attached to the polysaccharide chain to form the grafted polymer.
Said grafted polymer forms the backbone of the composite binder into which the filler(s) is incorporated to form the composite binder of Formula (I). In some embodiments, the filler(s) is an inorganic filler.
In some embodiments, the filler(s) is selected from a group comprising inorganic clays such as but not limited to bentonite.
In some embodiments, the grafted polymer is contacted with the filler(s) at a ratio ranging from about 12:1 to about 60:1.
In order to incorporate the filler(s) into the structure of the grafted polymer, the filler(s) is dissolved in a solvent and added dropwise to the reaction mixture comprising the viscous gel while maintaining the reaction mixture at a temperature ranging from about 70°C to about 80°C, preferably about 70°C. The solvent, in some embodiments, is water. In some embodiments, the ratio between the filler(s) and the solvent ranges from about 1:250 to about 1:200. The reaction mixture, in some embodiments, is subjected to mixing for a duration ranging from about 1 hour to about 1.5 hours and allowed to cool down to room temperature.
Dropwise addition of the filler(s) as described above leads to formation of the hybrid polymer composed of the grafted polymer backbone into which the filler is uniformly incorporated. Incorporation of the filler(s) into the grafted polymer backbone in the above method is essentially facilitated by solution polymerization in a single pot setup, without reliance on extremely high temperatures, making the synthesis simple and economical.
Figure 1 provides a schematic representation of the method of synthesis of the composite binder of Formula (I).
In some embodiments, the method of preparing the composite binder further comprises
washing the composite binder with a solvent;
optionally cutting the washed composite binder into smaller pieces; and
optionally subjecting the pieces of the composite binder to drying.
In some embodiments, the method of preparing the composite binder further comprises
washing the composite binder with a solvent; and
subjecting the washed the composite binder to drying.
In some embodiments, the method of preparing the composite binder further comprises
washing the composite binder with a solvent; and
cutting the washed composite binder into smaller pieces; and
subjecting the pieces of the composite binder to drying.
In non-limiting embodiments, the solvent employed for washing is selected from a group comprising acetone and ethanol or a combination thereof.
After addition of the complete volume of the solution of the filler, the resultant viscous gel like mixture is allowed to cool down to room temperature. Post cooling, the cooled hybrid polymer is washed with the solvent, optionally cut into smaller pieces and dried in an oven at a temperature of about 50°C to about 100°C, preferably about 60°C for about 8 hours to about 10 hours. In exemplary embodiments, the washing is performed with acetone.
Accordingly, in some embodiments, the method of preparing the composite binder of Formula (I) comprises
contacting a polysaccharide with an amide to form a reaction mixture;
adding polymerization initiator(s) to the reaction mixture to obtain a grafted polymer;
contacting the grafted polymer with a filler to obtain the composite binder;
washing the composite binder with a solvent;
optionally cutting the washed composite binder into smaller pieces; and
optionally subjecting the washed composite binder to drying.
In another embodiment, method of preparing the composite binder of Formula (I) comprises
contacting a polysaccharide with an amide to form a reaction mixture;
adding polymerization initiator(s) to the reaction mixture to obtain a grafted polymer;
contacting the grafted polymer with a filler to obtain the composite binder;
washing the composite binder with a solvent; and
subjecting the washed composite binder to drying.
In another embodiment, method of preparing the composite binder of Formula (I) comprises
contacting a polysaccharide with an amide to form a reaction mixture;
adding polymerization initiator(s) to the reaction mixture to obtain a grafted polymer;
contacting the grafted polymer with a filler to obtain the composite binder;
washing the composite binder with a solvent;
cutting the washed composite binder into smaller pieces; and
subjecting the pieces of the composite binder to drying.
Figure 4 depicts the results of FTIR analysis of the composite binder wherein the backbone of the composite binder is a grafted polymer wherein acrylamide is grafted onto starch. The peaks in the region of 3300-3600 cm-1 indicate the presence of O-H and N-H stretching of acrylamide. The peak at ~2930 cm-1 corresponds to symmetric C-H stretching present in starch. The peak at 1650 cm-1 is due to the presence of Amide I functional group and the peak at 1600 cm-1 is responsible for Amide II functional group present in polyacrylamide. In addition, the peak at 1425 cm-1 shows the presence of C-N stretching of polymer. The peak at 1110 cm-1 indicates was assigned to the Si-O stretching vibration. The peak at ~1030 cm-1 corresponds to stretching frequency of CH2-O-CH2 bond.

Figure 5 depicts the grafting nature of acrylamide on starch backbone in the grafted polymer prepared as per one of the exemplary embodiments of the present disclosure, as observed through SEM analysis. The dense fibrous structure that extends throughout the chain shows the presence of polyacrylamide chain. In addition, the dispersion of white like spherical particle on the polymer matrix marks the presence of the filler bentonite.
Figure 6 depicts the EDAX spectrum of the composite binder that reflects presence of all the necessary elements employed in the method of preparing the composite binder – i.e. the grafted polymer and the internalized/incorporated filler bentonite. The figure shows that bentonite employed is perfectly incorporated as a filler in the polymer matrix as observed in Figure 6.
The present disclosure further provides a compound binder comprising the above-described composite binder in combination with secondary filler(s) and secondary binder(s).
In some embodiments, the secondary filler is selected from a group comprising inorganic clays such as but not limited to bentonite.
In some embodiments, the secondary binder is selected from a group comprising cement and blast furnace slag or a combination thereof.
In one of the exemplary embodiments, the secondary filler is bentonite and the secondary binder is cement.
In some embodiments, the compound binder comprises the composite binder of Formula (I), the secondary filler and the secondary binder at a ratio ranging from about 1:1:2 to about 2:4:4.
The present disclosure further provides a method of preparing the compound binder as described above, wherein said method comprises –
mixing the composite binder of Formula (I) with the secondary filler(s) and the secondary binder(s).
In some embodiments, the mixing in the above method is achieved by method selected from a group comprising simple mixing, mechanical agitation, milling and blending in a mortar and pestle or any combination thereof. Said mixing, in some embodiments, is at a temperature ranging from about 24°C to about 27°C. In some embodiments, the mixing is performed for about 10 minutes to about 20 minutes.
In non-limiting embodiments, the compound binder finds application in the preparation of coke briquettes from coke fines. Said application finds further elaboration in the below paragraphs.
In some embodiments, the present disclosure provides use of the composite binder of Formula (I) or the compound binder as described above in the preparation of coke briquettes.
Also envisaged herein are the composite binder of Formula (I) or the compound binder as described above for use in the preparation of coke briquettes from coke fines.
The present disclosure further provides coke briquettes comprising coke fines and the composite binder of Formula (I) or the compound binder as described above. The coke briquettes find application in ferro-alloy production.
In some embodiments, the coke briquette comprises the coke fines and the composite binder of Formula (I) or the compound binder as described above at a ratio ranging from about 19:1 to about 9:1.
In some embodiments, the coke briquette comprises the coke fines and the composite binder of Formula (I) at a ratio ranging from about 49:1 to 9:1.
In some embodiments, the coke briquette comprises the coke fines and the compound binder at a ratio ranging from about 19:1 to 8:2.
In the coke briquette, the composite binder, after absorbing moisture, swells and encapsulates the coke particles surrounding the composite binder. It connects the coke particles by developing a network bridge between the particles. The secondary filler and secondary binder in the compound binder impart plasticity to the coke briquette and increase its temperature resistance.
An objective of the present disclosure is to provide coke briquettes having high/improved Cold Crushing Strength (CCS). High CCS ensures that the coke briquettes maintain their size distribution during handling and charging into the furnace. The coke briquettes of the present disclosure, in a non-limiting embodiment, have CCS ranging from about 900 kgf/briquette to about 982 kgf/briquette. Figure 7 shows a comparison of CCS between coke briquettes formed by employing different compound binders having the composite binder with varied starch to acrylamide ratio, respectively.
In some embodiments, the coke briquettes comprising the compound binder have higher CCS than those comprising the composite binder.
A further feature of the coke briquettes is their temperature resistance, wherein the briquettes comprising the composite binder or the compound binder do not decompose up to temperatures of about 1100oC.This helps the briquettes retain their structural integrity at high temperatures and prevents their breakdown into coke fines upon exposure to high temperatures that are typically characteristic of furnaces where the briquettes find application. Figure 8 depicts the results of the thermal degradation studies conducted on the coke briquettes of the present disclosure which shows that while the composite binder alone has comparatively lower resistance to thermal degradation, briquettes formed from coke fines and the compound binder have relatively high resistance to thermal degradation.
Further to the application of the composite binder and compound binder as described in the present disclosure, provided herein is a method for preparing coke briquettes comprising the composite binder of Formula (I) or the compound binder as described above, wherein said method comprises-
mixing coke fines with the composite binder of Formula (I) or the compound binder as described above to obtain a mixture; and
subjecting the mixture to compression to obtain the coke briquettes.
In some embodiments, the particle size of the coke fines to be employed in the preparation of the coke briquette as described above such that at least 80% of the batch of coke fines employed is less than about 3500 microns. In some embodiments, the coke fines have particle size ranging from about 0.045mm to about 8mm.
In some embodiments, moisture content of the coke fines to be employed in the preparation of the coke briquette ranges from about 2% to about 4%. The moisture content is naturally in the coke fines or is externally added.
In some embodiments, the coke fines and the composite binder of Formula (I) or the compound binder as described above are mixed at a ratio ranging from about 19:1 to about 9:1.
In some embodiments, the mixing is performed in an environment having moisture content ranging from about 3% to about 10%. The presence of moisture leads to swelling of the composite binder and the secondary binder in the compound binder.
In some embodiments, the mixing in the above method is achieved by method selected from a group comprising simple mixing, mechanical agitation, milling and blending in a mortar and pestle or any combination thereof. Said mixing, in some embodiments is at a temperature ranging from about 24°C to about 27°C, preferably for time ranging from about 10 minutes to about 20 minutes.
In some embodiments, post mixing, the mixture is subjected to compression to obtain the shape and form of the briquette. In non-limiting embodiments, the compression performed in a hydraulic press.
In some embodiments, the briquette, once obtained, is subjected to curing at ambient temperature for about 70 hours to about 90 hours.
On increasing the temperature after the coke fines and the composite binder or compound binder are mixed, a change in internal structure takes place and different phase formation occurs as a result of inter bonding of coke fines/particles with the composite binder to form a durable chain of complex. This is depicted in Figure 9.
Without being bound by theory, in some embodiments of the present invention, the coke briquettes comprising the compound binder may be prepared by combining pre-prepared compound binder with coke fines or in the alternative by simultaneous mixing of the individual components of the compound binder i.e. the composite binder, the secondary filler(s), the secondary binder(s) with the coke fines.
Accordingly, also provided in the present disclosure is a kit comprising components selected from a group comprising coke fines, the composite binder of formula (I), the secondary filler(s), the secondary binder(s) and the compound binder comprising the composite binder of formula (I) or any combination thereof along with an instruction manual.
In some embodiments, the kit comprises components selected from a group comprising coke fines, the composite binder of formula (I), the secondary filler(s) and the secondary binder(s) or any combination thereof along with an instruction manual.
In some embodiments, the kit comprises coke fines and the compound binder comprising the composite binder of formula (I) along with an instruction manual.
In some embodiments, the kit further comprises substances to enable efficient mixing of components such as but not limited to solvent(s), agitator(s) and any other agent(s) that enable ease of mixing.
The coke briquettes prepared using the composite binder or compound binder of the present disclosure find use in various furnacing applications.
In some embodiments, the present disclosure provides for use of the coke briquettes in the production of ferro-alloys.
While the present disclosure is susceptible to various modifications and alternative forms, specific aspects thereof have been shown by way of examples and drawings and are described in detail below. The Examples are only illustrative in nature and should not be construed to limit the scope of the present disclosure in any manner.
EXAMPLES
Materials and methods
The chemical reagents employed in the below examples are Potassium persulfate (Loba Chemie: 99%), Starch (Fisher Scientific: 99%), Acrylamide (Loba Chemie: 98%), Acetone (Rankem: 98%). OPC cement and sodium-based bentonite was available as commercial grade. Millipore double distilled water was used as the solvent for all synthesis purposes.
Example 1: Preparation of the composite binder of Formula (I)
About 100 ml of Millipore water was added to three neck round bottom flasks. At first, about 2 gm of starch was added. The temperature of the reaction was kept at about 70 °C under nitrogen environment throughout out the process. After about 10 minutes, about 10 gm of acrylamide was added to the homogeneous starch solution and subjected to mixing for about 30 minutes. The reagent ratio of starch: acrylamide was thus taken as about 1:5.
Thereafter, about 0.025 gm of potassium persulfate was added to the above reaction mixture and mixed for about 10 minutes. Potassium persulfate was used as an initiator for polymerization.
Formation of a viscous gel formation showed the start of polymerization reaction. About 0.5gm of bentonite was taken in a test-tube and was dispersed in about 10ml water and added dropwise for uniform distribution throughout the matrix. The flask was heated to a temperature of about 70 °C for about 1.5 hours.
After cooling to room temperature (about 15°C to 35°C), the viscous gel like material was washed with acetone.
The resultant dense polymer was cut into pieces and kept in oven at about 60 °C for drying for about 8 hours. A schematic representation of the synthesis mechanism is shown in Figure 1.
By varying the reagent ratio of acrylamide: starch (2:1 and 1:1), two other grades of starch grafted polymer were also prepared, following the same protocol.
Example 2: Estimation of grafting percentage in the composite binder of Example 1
Estimation of grafting percentage was calculated by using the following formula:
% G=(S_2-S_0)/S_0
where S0 is the weight of the starch and S2 is the weight of refined product.
It was observed from the analysis based on the above that higher grafting percentage was observed when the ratio of acrylamide:starch ratio was 2:1. The increasing profile of percentage grafting showed that at this specific reagent ratio, the acrylamide monomer found more grafting sites to form a chain network. However, in case of Acrylamide: Starch ratio of 5:1, decrease of grafting percentage (% G) occurred due to the formation of homopolymer. Results of said analysis are depicted in Figure 2, wherein depending on the grade of the grafted polymer, the grafting percentage was found to vary between about 55% to about 80%.
Example 3: Characterization of the composite binder of Example 1
FTIR analysis
Infrared spectroscopic studies were carried out for the composite binder of Example 1, over the range of 500–4000 cm-1 (Figure 4). The peak in the region of 3300-3600 cm-1 indicates the presence of O-H and N-H stretching of acrylamide. The peak at ~2930 cm-1 corresponds to symmetric C-H stretching present in starch. The peak at 1650 cm-1 is due to the presence of Amide I functional group and the peak at 1600 cm-1 is responsible for Amide II functional group present in polyacrylamide. In addition, the peak at 1425 cm-1 shows presence of C-N stretching of the polymer. The peak at 1110 cm-1 indicates the presence of was assigned to the Si-O stretching vibration, of the filler bentonite. The peak at ~1030 cm-1 corresponds to stretching frequency of CH2-O-CH2 bond.

SEM and EDAX analysis were carried out for the composite binder of Example 1. The fibrous morphology as observed from the SEM micrograph of the composite binder (Figure 5) indicates the grafting nature of acrylamide on starch backbone. The dense fibrous structure throughout the backbone polymeric chain indicates the presence of polyacrylamide chain. In addition, the dispersion of white like spherical particle on the polymer matrix marks the presence of bentonite incorporated into the grafted polymer.
The EDAX spectrum (Figure 6) of the composite binder reflects that all the necessary elements characteristic to the Composite binder of Formula (I) as prepared in Example 1 are present in the polymer. The EDAX spectrum further shows that bentonite was perfectly incorporated in the polymer matrix.
Example 4: Preparation of compound binder comprising the composite binder of Example 1
In order to prepare the compound binder, about 2gm of the composite binder of Example 1 was mixed with about 4gm of bentonite and about 4gm of cement at a temperature ranging from about 24°C to about 27°C by subjecting to mixing in Hobart mixer for about 20 minutes.
Following the above method, the following different compound binders were prepared, differing either in the combination of components or grades of the grafted polymer as prepared in Example 1.
Table 1:
Compound binder Grade of grafted polymer
(acrylamide:starch) Bentonite (%) Cement (%) Hybrid polymer (%)
Compound binder 1 1:1 40% 40% 20%
Compound binder 2 2:1 40% 40% 20%
Compound binder 3 5:1 40% 40% 20%
Comparative compound binder 40% 40% -

Example 5: Preparation of coke briquettes comprising the composite binder of Example 1 or the compound binder of Example 4
About 80 % of the coke fines employed in the Example had particle size less than 3300 microns. The distribution of sizes of particles were in such a way that 32 % of particles were of size in the range of about -3mm to +1 mm (defined in reference to sieve size). Analysis of size distribution of coke fines in the sample used for briquetting was carried out on a lab scale sieve shaker (RX-29-16). Results of the analysis are shown in Table 2. The results are further depicted in Figure 3.
Table 2:
Sieve Size (mm) Material Retain, (g) % Material Retained
- 8 + 6 28.83 3.07
- 6 + 4 141.37 14.17
- 4 + 3.15 132.39 13.17
- 3.15 + 1 329.27 32.76
- 1 + 0.85 31.89 3.24
-0.85+ 0.75 68.45 6.81
- 0.75 + 0.5 29.72 2.96
- 0.5 + 0.325 42.75 4.35
- 0.325 + 0.25 23.84 2.37
- 0.25 + 0.15 53.59 5.33
- 0.15+ 0.1 30.72 3.06
- 0.1 + 0.075 27.41 2.73
- 0.075 + 0.06 3.08 0.41
- 0.06 + 0.045 19.76 2.07
- 0.045 34.28 3.51
Total 1005 100.00

About 90gm of coke fines was mixed with about 10gm of the compound binder as prepared in Example 4 by subjecting to mixing in Hobart mixer at a temperature of about 24oC to 27oC while adding water to maintain moisture content of about 10%. The mixture was then subjected to compression in a hydraulic press to obtain the shape and form of briquettes. The obtained briquettes were thereafter subjected to curing at ambient temperature for about 72 hours.
Following the above method, the coke briquettes having the following compound binder were prepared –
Table 3:
Coke briquette Grade of grafted polymer
(acrylamide:starch) Bentonite (%) Cement (%) Hybrid polymer (%) Coke fines
Coke briquette 1 1:1 4% 4% 2% 90%
Coke briquette 2 2:1 4% 4% 2% 90%
Coke briquette 3 5:1 4% 4% 2% 90%
Coke briquette 4 2:1 - - 2% 98%
Comparative briquette 4% 4% 92%

Example 6: Analysis of the effect of the composite binder of Example 1 and the compound binder of Example 4 on cold crush strength of the briquettes
The different coke briquettes prepared in Example 5 were subjected to Cold Crushing Strength (CCS) analysis. The results obtained through said analysis are provided in the table below.
Table 4:
Coke briquette CCS (kgf/briquette)
Coke briquette 1 202
Coke briquette 2 982
Coke briquette 3 586
Coke briquette 4 896
Comparative briquette 70

As can be observed from the above, the coke briquettes prepared with the composite binder/compound binder of the present disclosure had higher CCS than similar briquettes prepared merely with combination of the secondary fillers and the secondary binders such as cement and bentonite. The coke briquette prepared employing the compound binder of the grade wherein the ratio of acrylamide:starch was about 2:1 was observed to have the highest CCS value (Figure 7).
Example 6: Analysis of the thermal degradation behaviour of the coke briquettes
The thermal degradation behaviour of the briquettes was analyzed by subjecting the coke briquettes to high temperature of about 1100 0C in a TGA instrument. This was done to analyze the property of temperature resistance of the briquettes. Figure 8 depicts the observations of the thermal degradation behaviour analysis, wherein the degradation behaviour of the coke briquette comprising the compound binder of Example 4 was found to be similar to that of a combination of cement and bentonite. Said property of temperature resistance appeared to be enhanced as compared to the behaviour observed for the composite binder of Example 1 alone.