Description:FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[see section 10 and rule13]

“COMPOSITIONS AND METHODS TO IMPROVE MEAN SIZE OF METALLURGICAL COKE”

Applicant:
TATA STEEL LIMITED
Jamshedpur, 831001, Jharkhand, India
Nationality: Indian

The following specification particularly describes the invention and the manner in which it is to be performed.


TECHNICAL FIELD
The present disclosure is in the field of metallurgy. In particular, the present disclosure relates to a composition and a method to increase the mean size of metallurgical coke.

BACKGROUND OF THE DISCLOSURE
Coke plays three roles in the operation of the blast furnace: chemical, thermal, and physical. Coke acts as a reducing agent and supplies heat for the reduction reaction. Coke’s physical properties are also of great importance for the blast furnace operation. The importance of coke’s physical properties is linked to the need to support the ferrous burden and to give a permeable matrix through which reducing gases can flow and molten material can percolate in the lower part of the blast furnace. These physical properties are related to its size (mean and distribution) and its resistance to breakage and abrasion. A proper sizing of furnace coke can contribute to the increase in the production of a blast furnace and to the lowering of coke rates. A very small size of coke entails the formation of an impermeable inert central core in the blast furnace whereas a large mean size with a narrow size distribution maintains adequate permeability.1-2.

The parameters that affect the coke size can be divided into three main factors: Coal factor, Operational factor and Additives. The coke size during carbonization is governed by the bulk density, rank and ash content of the coal charge.3 By a proper choice of the coal varieties in the blend, it is possible to control the size of coke. Stamping of an oven charge is well known to bring about marked improvement in the bulk density of the coal charge and cohesion of coke. On the other hand, stamp charging also tends to increase the fissuring tendency in the coke mass resulting in the reduction of lump coke size. The rank in terms of vitrinite reflectance of coal charge has been reported not to bring about any marked change in the size of stabilized coke reaching blast furnaces, however, the size of wharf coke tends to somewhat increase with the increase in the rank of coal charge. The ash content is the most important quality parameter of the coal charge influencing the coke size.4

Conditions of carbonization have a great effect on coke’s physical properties. Charging temperature, coking rate, duration of coking and final coking temperature all these parameters are interrelated and control the coke quality. It is quite understandable that the higher the oven temperature upon charging, the more rapid is the initial rate of heating. Some studies have been done on the heating rate which suggested that there is an appreciable reduction in higher size fraction with higher heating rate accompanied due to higher flue temperature.5 Apart from heating rate, quenching also influences coke quality. Upon quenching, the coke undergoes the same physico-mechanical changes as any solid. It has been established that depending on the rate of cooling, the stress in pieces of various sizes and shapes act in different ways. An increase in stress lead to formation of cracks and micro fissures due to which coke strength decreases. The hot red coke is pushed out from the oven; its appearance is characterized by a network of fissures extending throughout the coke mass, with a large central crack running through the height of the oven. During the subsequent quenching, handling and screening operations, breakage tends to occur along these cracks. The dominant method of cooling coke is wet quenching. In stepwise quenching, coke is cooled with water in steps. In high temperature, where the structure is denser and more strongly stressed, at the coke pushing temperature (1000-8500?) the quenching rate must be minimal as possible. Within the range from 850 to 6500? when the structure is still quite stressed and the temperature gradient between the surface of the coke and center is rather high, the quenching rate can be increased slightly. In the temperature range from 650-2000? the rate of quenching may be increased to such an extent as to prevent the generation of stress exceeding the ultimate strength of the coke.6

Studies have been performed by Jackman et al.7 on the effect of adding small percentages of anthracite fines and coke breeze to coal blends to determine their effect on coke size and strength. They observed that the addition of anthracite coal to the basic blend caused a decided increase in coke size and the addition of coke breeze caused a greater increase in the percentage of large size coke than that resulted from the addition of anthracite. This coke is less resistant to abrasion than that made from the anthracite blends. The addition of ten percent anthracite causes an increase in coke size equivalent to that produced by lengthening the coking time from 18 to 30 hours. The coke was found to be more abradable when large percentages of anthracite coal were used.

Although previous studies have explored ways to increase the mean size of coke, there is still a need in the art to provide compositions and methods to improve the mean size of coke under stamp charge condition. The present disclosure attempts to address this need.

STATEMENT OF THE DISCLOSURE
The present disclosure provides a composition comprising a blend of: a) an organic component comprising a polymer comprising resorcinol, melamine and formaldehyde; and b) an inorganic component comprising a carbon paste blended with a mixture of inert minerals in a first solvent, wherein said carbon paste comprises graphite powder, graphite fines, coke powder and petroleum coke powder mixed with a second solvent, and said mixture of inert minerals comprise cristobalite silica, tridymite silica, aluminum oxide, magnesium oxide, and titanium dioxide.

The present disclosure also provides a method for preparing the composition, comprising: a) preparing a polymer by i) heating a mixture of resorcinol, melamine and formaldehyde to a temperature of about 50-60°C for about 4-5 hours to obtain a reaction solution; ii) cooling the reaction solution to about 45°C following by letting the reaction solution to mature for about 24 hours to obtain a polymer; and iii) adding neutralizers to the polymer to maintain pH at about 6.5 to 7.5; b) preparing the organic component by mixing the polymer containing aldehyde with an extender; c) preparing the carbon paste by mixing graphite powder, graphite fines, coke powder and petroleum coke powder in a second solvent; d) preparing the inorganic component by mixing the carbon paste with the mixture of inert minerals comprising cristobalite silica, tridymite silica, aluminum oxide, magnesium oxide, and titanium dioxide in a first solvent; e) preparing the composition by blending the organic component and the inorganic component; and f) stabilizing the composition by maintaining the composition at room temperature for about 24 hours.

The present disclosure further provides a method for preparing metallurgical coke, comprising: a) mixing coals of various grades to obtain a coal blend; b) adding water and the composition of claim 1 to the coal blend to prepare a coal feed; c) introducing the coal feed into a stamping chamber to prepare a coal cake; d) introducing the coal cake into a coke oven; e) carbonizing the coal cake in the coke oven at a temperature of 900-1100 ? for a period of 5-28 hours to obtain hot coke; and f) cooling the hot coke to obtain metallurgical coke.

DETAILED DESCRIPTION OF THE DISCLOSURE
With respect to the use of 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. Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” or “containing” or “has” or “having” 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.

Reference throughout this specification to “some embodiments”, “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases “in some embodiments”, “in one embodiment” or “in an embodiment” in various places throughout this specification may not necessarily all refer to the same embodiment. It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The term “about” as used herein encompasses variations of +/-10% and more preferably +/-5%, as such variations are appropriate for practicing the present invention.

The present disclosure provides a composition that increases the mean size of coke while crushing thereby allowing coke to attain a higher strength. The composition is a viscous solution and is partly water soluble.

The composition of the present disclosure comprises a blend of an organic component and an inorganic component.

The organic component of the composition
The organic component of the composition comprises a polymer made from resorcinol, melamine and formaldehyde as monomers. In some embodiments, the ratio of resorcinol: melamine: formaldehyde is about 1:8:24 with a variance of up to 20%, i.e., the ratio ranges from 0.8: 6.4: 19.2 to 1.2: 9.6: 28.8.

The polymer is produced by mixing resorcinol, melamine and formaldehyde in the desired ratio and heating the mixture to a temperature of about 50-60? to initiate the reaction between the monomers. Once the reaction is started, the mixture is held at the temperature of about 50-60? for about 4-5 hours. In some embodiments, the mixture is held at the temperature of about 60? for about 4-5 hours. The reaction solution is then cooled to a temperature of about 45°C and left to mature for 24 hours. The pH is adjusted to a level of about 6.5 to about 7.5. The entire polymeric reaction is completed at or below the temperature of 60°C.

The polymer solution produced in the manner described above is mixed with extenders.

In some embodiments, the extender is sorbitol. The presence of formaldehyde in the polymer and the addition of the extender provides a desired flexibility when the composition is employed to increase the mean size of coke.

In some embodiments, the extender is added to the organic component in an amount of about 40 to 88% by weight of the organic component, including values and ranges thereof, such as about 40-85%, 40-80%, 40-70%, 40-60%, 50-88%, 50-85%, 50-80%, 50-70%, 60-88%, 60-85%, or about 60-80%.

In some embodiments, the organic component comprises about 20-60% by weight of the polymer and 40-80% by weight of the extenders.

The inorganic component of the composition
The inorganic component of the composition comprises a carbon paste blended with a mixture of inert minerals in a solvent (sometimes referred to herein as “a first solvent” to differentiate over the solvent used for preparing the carbon paste).

The carbon paste comprises a mixture of carbonaceous materials selected from graphite powder, graphite fines, coke powder, petroleum coke powder, or a combination thereof in a solvent (sometimes referred to herein as “a second solvent”).

In some embodiments, the mixture of carbonaceous materials comprises about 0.5 to 5 % by weight of graphite powder, about 0.5 to 9 % by weight of graphite fines, about 15 to 55 % by weight of coke powder and about 35 to 80 % by weight of petroleum coke powder. The carbon paste comprises about 62-80% by weight of the mixture of carbonaceous materials in about 20 - 38 % by weight of the second solvent. In some embodiments, the second solvent is selected from sorbitol, glycerol, aldehydes or a combination thereof.

The mixture of inert minerals comprises a fused mass comprising cristobalite silica, tridymite silica, aluminum oxide, magnesium oxide, and titanium dioxide. The mixture of inert minerals is prepared by subjecting the inert minerals to a high thermal roasting cycle. The high thermal roasting cycle comprises: i) heating the mixture of inert minerals to about 870-900 ?; and ii) holding the heated mixture to a temperature of about 900 to 1350 ? for a period of about 30 minutes to obtain a fused roasted mass of inert minerals. The fused roasted mass is cooled under atmospheric conditions.

In some embodiments, the heated mixture is held at a temperature of about 900-1300 ?, 900-1250 ?, 900-1200 ?, 900-1150 ?, 900-1100 ?, 900-1000 ?, 950-1300 ?, 950-1250 ?, 950-1200 ?, 950-1150 ?, 950-1100 ?, 1000-1350 ?, 1000-1300 ?, 1000-1200 ?, 1000-1100 ?, 1050-1350 ?, 1050-1300 ?, 1050-1250 ?, 1100-1350 ?, 1100-1250 ?, or about 1200-1350 ?, including values and ranges thereof.

The carbon paste and the fused mass of inert minerals are combined with the first solvent and mixed intensively to coat the carbonaceous materials and mineral grains to obtain the inorganic component. The inorganic component is a suspension of the carbon paste and fused mass of inert minerals in the organic solvents.

In some embodiments, the first solvent is selected from a glycol, isopropyl alcohol or a combination thereof.

Mixing the organic component and the inorganic component to prepare the composition
The organic component and the inorganic component are blended. The blended mixture is kept in a stabilization tank to attain a stability at room temperature for about 24 hours to obtain the composition of the present disclosure.

In the present composition, the organic component constitutes about 52-75% by weight of the composition, the carbon paste constitutes about 8-23% by weight of the composition and the mixture of inert minerals constitute about 8-25% by weight of the composition.

The present composition is expected to increase the nucleation sites in coals during coke making at a temperature range of about 400-600?. These nucleation sites are expected to provide a template for the coal metaplast to form and weld together the reactive and inert part. This is expected to help in a proper thermal diffusion in the coke during shrinkage leading to less cracks and bigger coke size.

The present composition is employed as an additive in coal blends to prepare metallurgical coke. The present composition improves the mean size of coke by about 5 to 10 points. The addition of even very small amounts of the present composition, such as about 0.5% of the present composition added to the coal blend, improves the mean size of metallurgical coke by as much as 5 points. The present composition improves the strength of coke by increasing the mean size of coke. That is, coke prepared from coal blends and the present composition shows more resistance to breaking and abrasion during stamp charging. By improving the mean size of coke, the present composition also increases the production efficiency of the blast furnace and provides lowering of coke rates. Further, the present composition also allows the incorporation of semi-soft coal and/or hard-coking coal in the coal blend for making coke without compromising the quality of coke. The incorporation of the present composition in a coal blend to prepare metallurgical coke maintains coke strength after reaction (CSR) of the metallurgical coke while improving the mean size of the metallurgical coke.

Methods for preparing metallurgical coke
The present disclosure provides a method for preparing metallurgical coke by employing the composition described herein.

To prepare metallurgical coke, coals of various grades are mixed to obtain a coal blend. In some embodiments, the coal blend comprises a mixture of coal grades selected from prime hard coking coal, captive prime hard coking coal, medium coking coal, semi-soft coking coal, and weak coking coal.

The present composition is mixed with a desired quantity of water and is added to or sprayed on the coal blend to prepare a coal feed. The amount of water added is such that the inherent moisture during the process is maintained between about 7.5 to 12%. The coal feed is introduced into a stamping chamber of a coal stamping machine to obtain a coal cake. The coal cake is introduced into a coke oven and is carbonized at a temperature of about 900-1100 ? for a period of about 5-28 hrs to obtain hot coke. The hot coke is cooled to obtain metallurgical coke.

In some embodiments, the present composition is added to the coal blend in an amount of about 0.5 to 3%, including values and ranges thereof, by weight of the coal blend. In some embodiments, the present composition is added to the coal blend in an amount of about 0.5-2.5%, 0.5-2%, 0.5-1.5%, 0.5-1%, 1-3%, 1-2.5%, or 1-2% by weight of the coal blend.

The present method for preparing metallurgical coke by employing the composition of the present disclosure improves the mean size of metallurgical coke by about 5-10 points. Further, the present method allows the incorporation of semi-soft coal and hard-coking coal in the coal blend without compromising the quality of coke.

It is to be understood that the foregoing descriptive matter is illustrative of the disclosure and not a limitation. While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. 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. Similarly, additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon description provided herein.

Descriptions of well-known/conventional methods/steps and techniques are omitted so as to not unnecessarily obscure the embodiments herein. Further, the disclosure herein provides for examples illustrating the above-described embodiments, and in order to illustrate the embodiments of the present disclosure certain aspects have been employed. The examples used herein for such illustration 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 following examples should not be construed as limiting the scope of the embodiments herein.

EXAMPLES

Example 1: Preparation of the composition
The composition was prepared in 4 steps.
Step 1: Preparing the polymer
First, the base polymer was produced by charging 1 part resorcinol, 8 parts melamine and 24 parts formaldehyde in a desired ratio into a reactor and heating the mixture to a temperature of 60°C to bring a reaction in the system. Once the reaction started, holding was done for about 4-5 hours and then the entire solution was cooled through limpet coils in the reactor as well as the cooling coils inside the reactor, so that, the entire reaction was completed below the temperature range of 60°C.

The polymer solution was cooled down to 45°C and left to mature for 24 hours. After this, neutralizers were added and the pH was maintained at a level of 6.5 to 7.5.

Step 2: Preparing the organic component
The polymer solution produced in Step 1 was mixed with about 40-80% by weight of sorbitol to obtain the organic component.

Step 3: Preparing the inorganic component
Carbonaceous materials – 3.5% graphite powder, 6% graphite fines, 42% coke powder and 48.5% petroleum coke powder – were taken to form a mix. 70% by weight of the mix was added to 30% by weight of the solvent to prepare the carbon paste.

A mixture of inert minerals was obtained from Ultra Mega Power Plants and Rejects of the Refractory Industry. The mixture was subjected to a high thermal roasting cycle where the mixture was heated to a tempertaure of 900 ?. The heated mixture was held at a temperature of 1350? for 30 minutes to obtain a fused roasted mass of inert minerals. The fused roasted mass was cooled under atmospheric conditions.

The carbon paste was mixed with the fused mass of inert minerals in a solvent such as glycol and/or isopropyl alcohol.

Step 4: Preparing the composition
The organic component from Step 2 and the inorganic component from Step 3 were charged sequentially into a blending vessel. After complete blending of the components, the composition was kept for stabilization in a separate stabilization tank to attain a stability at room temperature within 24 hours.

The physical properties of the composition were analysed and are listed below:
(a) Appearance: Black viscous solution
(b) Viscosity at 25°C in Brookfield Viscometer by Spindle No. 4: 1300 ± 500 Cps.
(c) pH: 7.0 ± 1.0
(d) Specific Gravity : 1.12 ± 0.035
(e) Partly soluble in water

Example 2: Carbonization study
A series of carbonization tests were conducted in a 7-kg carbolite test oven under stamp charging conditions. The carbonization tests were performed to study the effect of the composition on coke properties. Water was added to the coal blend to obtain the desired value of moisture content. The coal cake was made inside a cardboard box keeping the bulk density 1150 kg/m3. Before charging the coal cake into the oven, it was ensured that the empty oven temperature is 900±5 ?. After 5 h of carbonization time, the hot coke was pushed out and quenched with water. The coke samples were tested for coke strength after reaction (CSR) and CRI (coke reactivity indices). The CSR was measued by using the following NSC method: 200 g coke of 19-21 mm size is heated in a reaction tube (78 mm diameter X 210 mm length) at 11000? for two hours during which CO2 is passed at 5 L/min. The percentage loss in weight of coke during the above reaction is reported as the coke reactivity test (CRI). This reacted coke is further tested by rotating in a I drum (127 mm diameter X725 mm length) for 30 min at a speed of 20 rpm. The coke is then screened on a 10 mm sieve and the % of + 10 mm fraction is reported as the coke strength after reaction (CSR).
Results:
Different coals were used for blend preparation. Coal A is an imported prime hard coking coal, coal B and coal C is captive prime hard coking and medium coking coal. Coal D and coal E are imported semi-soft coking coal. Coal F is a weak coking coal. Characterization: The coals were characterized in terms of ash, volatile matter (VM), crucible swelling number (CSN) and fluidity. The details of the tests are as follows:

Ash determination: Ash is determined by following ASTM standard D 3174-11. 1 gm of 250 mm size sample is taken to a weighed capsule. Then the sample is placed in a cold muffle furnace and heated gradually at such a rate that the temperature reached 4500C to 5000C by 1 hr. At the end of the 2 hr it will reach 9500C. After cooling the weight of the sample then measured and ash is calculated by weight difference.

VM determination: Ash is determined by following ASTM standard D 3175-11. In this test, 1 gm of 250 mm size sample is taken in a covered platinum crucible and heated in a furnace of 9500C for 7 min. The VM is calculated by weight difference.

Crucible swelling number: Crucible swelling number test has been done by following ASTM D720-91 (2010). In this test, 1 gm of sample (-0.212 mm size) is taken in a translucent squat shaped silica crucible and the sample is leveled by tapping the crucible 12 times. The crucible is covered with a lid and heated under standard conditions, either by a special type of gas burner or muffle furnace. After the test the shape of coke button is compared with a standard chart and accordingly, the crucible swelling number (0 to 9) is assigned to the coal sample.

Table 1: Properties of different coals:
Coal Coal Ash VM Crucible Swelling number
Goonyella A 9.0 23.0 8
West Bokaro B 17.0 24.0 7
Jharia C 18.0 22.0 5
CD HCC D 8.0 23.0 5
SMM E 8.4 32.5 8
Blackwater F 8.2 25.4 4

Table 2: Blend composition and coking properties
1 2 3 4 5
% Coal A = 15
Coal B = 24
Coal C = 5
Coal D = 19
Coal E = 23
Coal F = 14
Present composition = 0 Coal A = 15
Coal B = 24
Coal C = 5
Coal D = 19
Coal E = 23
Coal F = 14
Present composition = 0.7 Coal A = 15
Coal B = 24
Coal C = 5
Coal D = 19
Coal E = 23
Coal F = 14
Present composition = 1 Coal A = 15
Coal B = 24
Coal C = 5
Coal D = 19
Coal E = 23
Coal F = 14
Present composition = 2 Coal A = 15
Coal B = 24
Coal C = 5
Coal D = 19
Coal E = 23
Coal F = 14
Present composition = 3
CSR 41.5 40.60 39.01 43.50 45.40
Mean Size, mm 43.15 45.37 47.84 50.93 52.14

Blend 1 is the base blend of coke plant. In blend 2, 0.5% of prime hard coking coal was replaced by 0.5 % of the present composition. The above results show that there was ~ 5 mm improvement in the coke mean size. In blend 3, 1.0 % prime hard coking coal was replaced by the present composition which led to an increase in the mean size by 6 points over the base blend.

References:
1. M.A. Diez, R. Alvarez and C. Barriocanal, International Journal of Coal Geology, 50 (2002), 389.
2. H. Bertling, ISIJ International, 39 (1999), 617.
3. K.C. Banerji, T. Venugopal and A.K. Mazumdar, COMA, 1976, 301-308.
4. H.N. Prashad, R.S. Karmakar, M. Tiwary, B.K. Singh and A.S. Dhillon, Tata Search, (1996), 52.
5. C. E. Marshall, D. K. Tompkins, D. F. Branagan and J. L. Sanderson, Note on Charging temperature and Coke Quality Representative Study Results of American, Australian and Japanese Coals.
6. R. Sharma, P. S. Dash, S. H. Krishnan and D. Kumar, Tata Search, (2004), 40.
7. H. W. Jackman, P. W. Henline and F. H. Reed, Illinois State Geological Survey, Circular, (1956). 213. , Claims:We Claim:
1. A composition comprising a blend of:
a. an organic component comprising a polymer comprising resorcinol, melamine and formaldehyde; and
b. an inorganic component comprising a carbon paste blended with a mixture of inert minerals in a first solvent, wherein said carbon paste comprises graphite powder, graphite fines, coke powder and petroleum coke powder mixed with a second solvent, and said mixture of inert minerals comprise cristobalite silica, tridymite silica, aluminum oxide, magnesium oxide, and titanium dioxide.
2. The composition as claimed in claim 1, wherein resorcinol, melamine and formaldehyde are mixed in a ratio of 1:8:24 with a variance of up to 20%.
3. The composition as claimed in claim 1 or 2, wherein the organic component comprises an extender.
4. The composition as claimed in claim 3, wherein the extender is sorbitol.
5. The composition as claimed in any one of claims 1-4, wherein the organic component constitutes about 52-75% by weight of the composition.
6. The composition as claimed in any one of claims 1-5, wherein the first solvent is selected from a glycol, isopropyl alcohol or a combination thereof.
7. The composition as claimed in any one of claims 1-6, wherein the carbon paste comprises 0.5 to 5 % by weight of graphite powder, 0.5 to 9 % by weight of graphite fines, 15 to 55 % by weight of coke powder and 35 to 80 % by weight of petroleum coke powder mixed in the second solvent.
8. The composition as claimed in any one of claims 1-7, wherein the carbon paste constitutes about 8-23% by weight of the composition.
9. The composition as claimed in any one of claims 1-8, wherein the second solvent is selected from sorbitol, glycerol, aldehydes or a combination thereof.
10. The composition as claimed in any one of claims 1-9, wherein the mixture of inert minerals comprises cristobalite silica, tridymite silica, aluminum oxide, magnesium oxide and titanium dioxide.
11. The composition as claimed in any one of claims 1-10, wherein the mixture of inert minerals constitutes about 8-25% by weight of the composition.
12. A method for preparing metallurgical coke, comprising:
a. mixing coals of various grades to obtain a coal blend;
b. adding water and the composition of claim 1 to the coal blend to prepare a coal feed;
c. introducing the coal feed into a stamping chamber to prepare a coal cake;
d. introducing the coal cake into a coke oven;
e. carbonizing the coal cake in the coke oven at a temperature of 900-1100 ? for a period of 5-28 hours to obtain hot coke; and
f. cooling the hot coke to obtain metallurgical coke.
13. The method as claimed in claim12, wherein the composition of claim 1 is added to the coal blend in an amount of about 0.5-3% by weight of the coal blend.
14. The method as claimed in claim 12 or 13, wherein the method provides for incorporation of semi-soft coal and hard-coking coal in the coal blend.
15. The method as claimed in any one of claims 12-14, wherein the method maintains coke strength after reaction (CSR) of the metallurgical coke while improving mean size of the metallurgical coke.
16. The method as claimed in any one of claims 12-15, wherein the method improves a mean size of metallurgical coke by about 5 points.
17. A method for preparing the composition as claimed in claim 1, comprising:
a. preparing a polymer by:
i. heating a mixture of resorcinol, melamine and formaldehyde to a temperature of about 50-60°C for about 4-5 hours to obtain a reaction solution;
ii. cooling the reaction solution to about 45°C following by letting the reaction solution to mature for about 24 hours to obtain a polymer; and
iii. adding neutralizers to the polymer to maintain pH at about 6.5 to 7.5;
b. preparing the organic component by mixing the polymer with an aldehyde and an extender;
c. preparing a carbon paste by mixing graphite powder, graphite fines, coke powder and petroleum coke powder in a second solvent;
d. preparing the inorganic component by mixing the carbon paste with the mixture of inert minerals comprising cristobalite silica, tridymite silica, aluminum oxide, magnesium oxide, and titanium dioxide in a first solvent;
e. preparing the composition by blending the organic component and the inorganic component; and
f. stabilizing the composition by maintaining the composition at room temperature for about 24 hours.
18. The method as claimed in claim 17, wherein resorcinol, melamine and formaldehyde are mixed in a ratio of about 1:8:24 with a variance of up to 20%.
19. The method as claimed in claim 17 or 18, wherein the extender is added to the organic component in an amount of 40 to 80% by weight.
20. The method as claimed in any one of claims 17-19, wherein the carbon paste is prepared by mixing about 0.5 to 5 % by weight of graphite powder, about 0.5 to 9 % by weight of graphite fines, about 15 to 55 % by weight of coke powder and about 35 to 80 % by weight of petroleum coke powder.
21. The method as claimed in any one of claims 17-20, wherein the second solvent is selected from sorbitol, glycerol, aldehydes or a combination thereof.
22. The method as claimed in any one of claims 17-21, wherein the mixture of the inert minerals comprising a fused mass of cristobalite silica, tridymite silica, aluminum oxide, magnesium oxide and titanium dioxide is prepared by heating the mixture to a temperature of about 870-900? to obtain a heated mixture, holding the heated mixture to a temperature of about 900 to 1350 ? for a period of about 30 minutes to obtain a fused roasted mass of inert minerals, and cooling the fused roasted mass under atmospheric conditions.
23. The method as claimed in any one of claims 17-22, wherein the first solvent is selected from a glycol, isopropyl alcohol or a combination thereof.