Description:TECHNICAL FIELD
The present disclosure relates to the field of metallurgy. Particularly, the present disclosure relates to a pellet composition comprising iron ore fines, carbonaceous material, binder, iron ore sinter fines and fluxing agent, optionally along with calcium oxide source. The disclosure further relates to a method for preparing iron ore pellet employing said pellet composition and to the obtained iron ore pellet.

BACKGROUND OF THE DISCLOSURE
Pelletizing is an agglomeration process wherein the fine iron ore particles are converted into spherical bodies. Pelletizing involves grinding of iron ore, followed by agglomeration of fine iron ore particles into green balls by adding one or several binders and additives as per the requirement followed by indurating at a required temperature to obtain pellets. Pellet composition plays a vital role to control the blast furnace slag chemistry which in turn governs the blast furnace productivity.

Particularly, the properties of iron ore pellets depend on the type of raw material used and indurating conditions. In the past, it is observed that the type and amount of fluxes added and moisture content of the raw materials, particularly moisture content of the iron ore fines play an important role in pellet properties and pellet productivity.

Thus, there appears to a be a constant need for improving iron ore pellet property and pellet productivity.

STATEMENT OF THE DISCLOSURE
Accordingly, the present disclosure relates to a pellet composition which improves the productivity of iron ore pellet. The pellet composition comprises iron ore fines, carbonaceous material, binder, iron ore sinter fines and fluxing agent, optionally along with calcium oxide source.

The present disclosure further relates to a method for preparing iron ore pellet, said method comprising- preparing the composition described above; and adding solvent to the composition and preparing pellet, followed by heating the pellet to obtain the iron ore pellet.

The present disclosure further relates to iron ore pellet comprising the composition described above.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURE
In order that the present 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 figure. The figure 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, where:

FIGURE 1 provides an exemplary schematic representation of production of iron ore pellets employing iron ore sinter fines.

DETAILED DESCRIPTION OF THE DISCLOSURE
Definitions:
Unless otherwise defined, all terms used in the disclosure, including technical and scientific terms, have meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included for better understanding of the present disclosure.

As used herein, the singular forms ‘a’, ‘an’ and ‘the’ include both singular and plural referents unless the context clearly dictates otherwise.

The term ‘comprising’, ‘comprises’ or ‘comprised of’ as used herein are synonymous with ‘including’, ‘includes’, ‘containing’ or ‘contains’ and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps.

The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within the respective ranges, as well as the recited endpoints.

The term ‘about’ as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of ±10% or less, preferably ±5% or less, more preferably ±1% or less and still more preferably ±0.1% or less of and from the specified value, insofar such variations are appropriate to perform the present disclosure.

The term ‘cold compressive strength (CCS)’ of the pellets indicate the ability of the pellets to withstand the load during their storage, handling and the load of the burden material in the reduction furnace. The pellets for use in the blast furnace should have CCS in the range of 200 kg/pellets to 300 kg/pellets.

The term ‘reduction degradation index (RDI)’ indicates disintegration of the pellets. It is a quantitative measure of disintegration of iron ore pellets that occurs in the upper part of the blast furnace after some reduction. Pellets with a high degree of reduction disintegration generates fines in the top of the furnace which affects the flow distribution within the blast furnace.

The term ‘Tumbler Index’ indicates a relative measure of the resistance of the material to breakage or degradation by impact. Higher the tumbler index, excellent is the physical properties of the iron ore pellets.

The present disclosure relates to a pellet composition comprising iron ore fines, carbonaceous material, binder, iron ore sinter fines and fluxing agent, optionally along with calcium oxide source.

In some embodiments of the present disclosure, the composition comprises iron ore fines, carbonaceous material, binder, iron ore sinter fines and fluxing agent.

In some embodiments of the present disclosure, the composition comprises iron ore fines, carbonaceous material, binder, iron ore sinter fines, fluxing agent and calcium oxide source.

In some embodiments of the present disclosure, the carbonaceous material is selected from a group comprising coke breeze, nut coke, anthracite coal, CDQ dust, GCP sludge, flue dust and combinations thereof.

In some embodiments of the present disclosure, the binder is selected from a group comprising bentonite, micro silica, fly ash and combinations thereof.

In some embodiments of the present disclosure, the fluxing agent is selected from a group comprising dolomite, olivine, wollastonite, pyroxenite, peridotite and combinations thereof.

In some embodiments of the present disclosure, the calcium oxide source is selected from a group comprising limestone, calcined lime, hydroxide lime and combinations thereof.

In some embodiments of the present disclosure, the iron ore fines is in an amount ranging from about 80 wt% to 95 wt%.

In some embodiments of the present disclosure, the iron ore fines is in an amount of about 80 wt%, about 81 wt%, about 82 wt%, about 83 wt%, about 84 wt%, about 85 wt%, about 86 wt%, about 87 wt%, about 88 wt%, about 89 wt%, about 90 wt%, about 91 wt%, about 92 wt%, about 93 wt%, about 94 wt% or about 95 wt%.

In some embodiments of the present disclosure, the carbonaceous material is in an amount ranging from about 1 wt% to 10 wt%.

In some embodiments of the present disclosure, the carbonaceous material is in an amount of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt% or about 10 wt%.

In some embodiments of the present disclosure, the binder is in an amount ranging from about 0.1 wt% to 1.5 wt%.

In some embodiments of the present disclosure, the binder is in an amount of about 0.1 wt%, about 0.2 wt% about 0.3 wt%, about 0.4 wt%, about 0.5 wt%, about 0.6 wt%, about 0.7 wt%, about 0.8 wt%, about 0.9 wt%, about 1.0 wt%, about 1.1 wt%, about 1.2 wt%, about 1.3 wt%, about 1.4 wt% or about 1.5 wt%.

In some embodiments of the present disclosure, the iron ore sinter fines is in an amount ranging from about 3 wt% to 25 wt%.

In some embodiments of the present disclosure, the iron ore sinter fines is in an amount of about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, about 16 wt%, about 17 wt%, about 18 wt%, about 19 wt%, about 20 wt%, about 21 wt%, about 22 wt%, about 23 wt%, about 24 wt% or about 25 wt%.

In some embodiments of the present disclosure, the fluxing agent is in an amount ranging from about 1wt% to 10 wt%.

In some embodiments of the present disclosure, the fluxing agent is in an amount of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt% or about 10 wt%.

In some embodiments of the present disclosure, the calcium oxide source is in an amount ranging from about 1 wt% to 10 wt%.

In some embodiments of the present disclosure, the calcium oxide source is in an amount of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt% or about 10 wt%.

In some embodiments of the present disclosure, the iron ore sinter fines comprises total iron (Fe (t)) ranging from about 45 wt% to 60 wt%, ferrous oxide (FeO) ranging from about 7 wt% to 14 wt%, calcium oxide (Cao) ranging from about 9 wt% to 14 wt%, magnesium oxide (MgO) ranging from about 1.5 wt% to 2.5 wt%, aluminum oxide (Al2O3) ranging from about 1.5 wt% to 3 wt% and silicon dioxide (SiO2) ranging from about 2.5 wt% to 5 wt%.

In some embodiments of the present disclosure, the iron ore fines comprises about 60 wt% to 64 wt% of Fe(t), about 3 wt% to 4.8 wt% of SiO2, about 2 wt% to 4 wt% of Al2O3, about 0.02 wt% to 0.5 wt% of CaO and about 0.01 wt% to 0.3 wt% of MgO.

In some embodiments of the present disclosure, the iron ore fines comprises about 63.48 wt% of Fe(t), about 3.05 wt% of SiO2, about 2.75 wt% of Al2O3, about 0.04 wt% of CaO and about 0.01 wt% of MgO.

In some embodiments of the present disclosure, the iron ore fines have loss on ignition (LOI) ranging from about 1 wt% to 5 wt% .

In some embodiments of the present disclosure, the iron ore fines have loss on ignition (LOI) of about 1 wt%, about 2 wt %, about 3 wt%, about 4 wt% or about 5 wt%.

In some embodiments of the present disclosure, the iron ore fines have loss on ignition (LOI) of about 2.75 wt%.

In some embodiments of the present disclosure, the iron ore fines have moisture content ranging from about 6 to 10 %.

In some embodiments of the present disclosure, the iron ore fines have moisture content of about 6%, about 7%, about 8%, about 9% or about 10%.

In some embodiments of the present disclosure, moisture content of the iron ore sinter fines is zero.

In some embodiments of the present disclosure, loss on ignition (LOI) of the iron ore sinter fines is zero.

In some embodiments of the present disclosure, the pellet composition comprising the iron ore fines, the carbonaceous material, the binder, the iron ore sinter fines and the fluxing agent, optionally along with calcium oxide source improves pellet productivity and maintains pellet quality at higher productivity. The said improvement in pellet productivity is due to presence of the iron ore sinter fines in the composition and due to zero moisture content and zero loss on ignition of the iron ore sinter fines.

In some embodiments of the present disclosure, the pellet composition helps in maintaining basicity of iron ore pellet in the range of 0.1 to 0.9.

In some embodiments of the present disclosure, the pellet composition helps in maintaining basicity of iron ore pellet at about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8 or about 0.9.

In some embodiments of the present disclosure, calcium oxide content in the iron sinter fines of the composition aids in adjusting the basicity of iron ore pellet, as a result, the amount of iron ore sinter fines that is added to the composition is determined depending on pellet chemistry.

In some embodiments of the present disclosure, the composition has particle size ranging from about 0.1 microns to 150 microns.

In some embodiments of the present disclosure, about 25% to 30% of the composition has particle size of less than 10 microns.
In some embodiments of the present disclosure, about 55% to 65% of the composition has particle size of less than 45 microns.

In some embodiments of the present disclosure, about 88% to 95% of the composition has particle size of less than 150 microns.

The present disclosure further relates to a method of preparing iron ore pellet.

In some embodiments of the present disclosure, the method of preparing iron ore pellet comprises:
- preparing the composition described above; and
- adding solvent to the composition and preparing pellet, followed by heating the pellet to obtain the iron ore pellet.

In some embodiments of the present disclosure, the solvent is water.

In some embodiments of the present disclosure, the solvent is in an amount ranging from about 8 % to 11% by weight of the composition.

In some embodiments of the present disclosure, the solvent is in an amount of about 8%, about 9%, about 10% or about 11% by weight of the composition.

In some embodiments of the present disclosure, the composition described above is prepared by:
- mixing the iron ore fines, the carbonaceous material and the fluxing agent, optionally along with the calcium oxide source to obtain a mixture, followed by drying the mixture;
- adding the iron ore sinter fines to the dried mixture, followed by milling; and
- adding the binder to the milled mixture to obtain the composition.

In some embodiments of the present disclosure, the composition described above is prepared by:
- mixing the iron ore fines, the carbonaceous material, the fluxing agent and the calcium oxide source to obtain a mixture, followed by drying the mixture;
- adding the iron ore sinter fines to the dried mixture, followed by milling; and
- adding the binder to the milled mixture to obtain the composition.

In some embodiments of the present disclosure, the composition described above is prepared by:
- mixing the iron ore fines, the carbonaceous material and the fluxing agent to obtain a mixture, followed by drying the mixture;
- adding the iron ore sinter fines to the dried mixture, followed by milling; and
- adding the binder to the milled mixture to obtain the composition.

In some embodiments of the present disclosure, the composition described above is prepared by adding 1 wt% to 3 wt% of the carbonaceous material having particle size of less than 10 mm and 1 wt % to 10 wt% of fluxing agent, optionally along with calcium oxide source to about 80 wt% to 95 wt% of the iron ore fines having particle size of less than 10 mm, followed by mixing and drying the mixture so that the moisture content of the mixture is less than 1 %. To the dried mixture, about 5 wt% to 15 wt% of the iron ore sinter fines are added and milled to obtain a ground mixture. To the ground mixture about 0.1 wt% to 1.5 wt% of the binder is added and mixed thoroughly until a stable composition is obtained.

In some embodiments of the present disclosure, the iron ore fines has particle size ranging from about 0.15 mm to 10 mm, the carbonaceous material has particle size ranging from about 0.15 mm to 30 mm, the fluxing agent has particle size ranging from about 1 mm to 10 mm, the iron ore sinter fines has particle size ranging from about 3 mm to 5 mm and the calcium oxide source has particle size ranging from about 0.15 mm to 10 mm.

In some embodiments of the present disclosure, the dried mixture has moisture content of less than 1%.

In some embodiments of the present disclosure, the dried mixture has moisture content of 0 to 1%.

In some embodiments of the present disclosure, the dried mixture has moisture content of 0, about 0.1%, about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9% or about 1%.

In some embodiments of the present disclosure, the milled mixture has particle size ranging from about 0.045 mm to 0.15 mm.
In some embodiments of the present disclosure, the milled mixture has particle size of about 0.045 mm, about 0.05 mm, about 0.055 mm, about 0.06 mm, about 0.065 mm, about 0.07 mm, about 0.075 mm, about 0.08 mm, about 0.085 mm, about 0.09 mm, about 0.095 mm, about 0.01 mm or about 0.015 mm.

In some embodiments of the present disclosure, preparing pellet comprises pelletizing mixture of the solvent and the composition to obtain iron ore pellet having size ranging from about 6mm to 16 mm.

In some embodiments of the present disclosure, the iron ore pellet has size of about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm or about 16 mm.

In some embodiments of the present disclosure, the heating is carried out under oxidizing atmosphere at a temperature ranging from about 1250 ºC to 1330 ºC.

In some embodiments of the present disclosure, the heating is carried out under oxidizing atmosphere at a temperature of about 1250 ºC, about 1260 ºC, about 1270 ºC, about 1280 ºC, about 1290 ºC, about 1300 ºC, about 1310, about 1320 ºC or about 1330 ºC.

In some embodiments of the present disclosure, the heating is carried out in a furnace including but not limited to straight grate furnace, grate kiln furnace and shaft furnace.

In some embodiments of the present disclosure, the method of preparing the iron ore pellet comprises- adding 1 wt% to 3 wt% of the carbonaceous material having particle size of less than 10 mm and 1 wt % to 10 wt% of fluxing agent, optionally along with calcium oxide source to about 80 wt% to 95 wt% of the iron ore fines having particle size of less than 10 mm, followed by mixing and drying the mixture so that the moisture content of the mixture is less than 1 %. To the dried mixture, about 5 wt% to 15 wt% of the iron ore sinter fines are added and milled to obtain a ground mixture. To the ground mixture, about 0.1 wt% to 1.5 wt% of the binder is added and mixed thoroughly until a stable composition is obtained. About 8% to 11% of solvent per total mass of the composition is added and mixed in a mixer to get the green mix material. The green mix material is pelletized in a pelletizing disc or pelletizing drum to obtain green pellets of size ranging from about 6 mm to 16 mm, wherein about 60% to 65% of the pellets have size ranging from about 9 mm to 12.5 mm and about 25% to 30% of the pellets have size ranging from about 12.5 mm to 16 mm. The obtained pellets are indurated in a furnace including not limited to straight grate furnace, grate kiln furnace, circular pelletizing and shaft furnace, under oxidizing atmosphere at a temperature ranging from about 1250 ºC to 1330 ºC to obtain iron ore pellet.

In some embodiments of the present disclosure, the method of preparing the iron ore pellet leads to pellet quantity gain of at least 1%.

In some embodiments of the present disclosure, the method of preparing the iron ore pellet leads to pellet quantity gain of at least 1%, at least 1.25%, at least 1.50%, at least 1.75% or at least 2%.

In some embodiments of the present disclosure, the method of preparing the iron ore pellet reduces moisture load in dryer and loss on ignition (LOI) load during induration.

In some embodiments of the present disclosure, during the preparation of the composition described above, the iron ore sinter fines are directly fed into milling, bypassing drying. This reduces overall LOI input in induration (heating in furnace) during pellet preparation. Thus, for each unit of iron ore sinter fines used in the composition, there is same unit of extra pellet production, that is, improvement in pellet productivity.

In some embodiments of the present disclosure, use of iron ore sinter fines in the composition reduces or removes the need of addition of calcium oxide source into the composition for preparing the iron ore pellet.

In some embodiments of the present disclosure, use of iron ore sinter fines in the composition reduces the amount of fluxing agent required in the composition for preparing the iron ore pellet.

The present disclosure further relates to an iron ore pellet prepared according to the method described above.

In some embodiments of the present disclosure, the iron ore pellet comprises the composition described above.

In some embodiments of the present disclosure, the iron ore pellet has size ranging from about 6 mm to 16 mm.

In some embodiments of the present disclosure, the iron ore pellet has size of about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm or about 16 mm.

In some embodiments of the present disclosure, the iron ore pellet has cold compressive strength ranging from about 210 kg/pellet to 240 kg/pellet.

In some embodiments of the present disclosure, the iron ore pellet has cold compressive strength of about 210 kg/pellet, about 212 kg/pellet, about 214 kg/pellet, about 216 kg/pellet, about 218 kg/pellet, about 220 kg/pellet, about 222 kg/pellet, about 224 kg/pellet, about 226 kg/pellet, about 228 kg/pellet, about 230 kg/pellet, about 232 kg/pellet, about 234 kg/pellet, about 236 kg/pellet, about 238 kg/pellet or about 240 kg/pellet.

In some embodiments of the present disclosure, the iron ore pellet has tumbler index ranging from about 92% to 96%.

In some embodiments of the present disclosure, the iron ore pellet has tumbler index of about 92%, about 93%, about 94%, about 95% or about 96%.

In some embodiments of the present disclosure, the iron ore pellet has reduction degradation index (RDI) ranging from about 2% to 8%.

In some embodiments of the present disclosure, the iron ore pellet has reduction degradation index of about 2%, about 3%, about 4%, about 5%, about 6%, about 7% or about 8%.

In some embodiments of the present disclosure, the iron ore pellet has basicity ranging from about 0.1 to 0.9.

In some embodiments of the present disclosure, the iron ore pellet has basicity of about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8 or about 0.9.

It is to be understood that the foregoing description is illustrative not a limitation. While considerable emphasis has been placed herein on 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 may be practiced and to further enable those of skill in the art to practice the embodiments. Accordingly, following examples should not be construed as limiting the scope of the embodiments herein.

EXAMPLE

Example 1: Preparing Iron ore pellet
i. Preparing Composition
Raw materials used- Iron ore, anthracite coal, limestone, olivine, bentonite and iron ore sinter fines.
The said raw materials were grounded separately in ball mill, followed by mixing raw materials in three different batches in turbo mixture to obtain 3 different compositions. Table 1 describes proportion of the raw materials employed to prepare the composition. Further, Table 2 describes constituents of each of the raw materials.
Raw Material, wt.% Composition- A Composition- B Composition-C
Iron ore 92 88 85.5
Limestone 2.2 1 0
Olivine 3.8 3.6 3.5
Iron ore sinter fines 0 5 10
Bentonite 0.5 0.5 0.5
Anthracite coal 1.5 1.5 1.5

Table 1:
Constituents, wt.% Iron ore Bentonite Limestone Olivine Anthracite Coal Iron ore sinter Fines
Fe(t) 63.48 9.72 - 4.51 0.65 55
SiO2 3.05 45.97 1.55 41.22 5.2 4.5
Al2O3 2.75 14.49 0.31 0.49 2.21 2.4
CaO 0.04 1.78 52.01 0.37 0.15 12.6
MgO 0.01 2.24 0.43 49.35 0.14 2.4
LOI 2.75 15 44.56 1.05 - 0
Fixed carbon - - - - 85
Moisture 7 10 7 9 12 0
Table 2:

ii. Preparing iron ore pellets
The obtained compositions (Composition-A, Composition-B and Composition-C) were mixed with about 8% to 11% of water per total weight of the composition, respectively to obtain green mix material. The green mix materials were pelletized separately in pelletizing disc of diameter of about 600 mm and a depth of about 200 mm. The obtained pellets have size ranging from about 10 mm to12.5 mm. Loss of ignition (LOI) of the pellets was measured. The moisture content of the pellets was also measured and it was found to be 9%.

Firing (heating) of the pellets was carried out in Inconel basket (100mm*100mm*100mm) in an electrically heated rapid heating nabertherm furnace at a temperature of about 1300 ºC in oxidizing atmosphere. The pellets were cooled by air and subjected to analysis, the results of which are tabulated in Table 3.

Parameters UoM Pellets from Composition- A Pellets from Composition- B Pellets from Composition- C
Fe(t) % 62.02 61.94 61.93
CaO % 1.35 1.34 1.31
MgO % 1.81 1.79 1.80
Al2O3 % 2.72 2.61 2.71
Green pellet LOI % 5.06 4.22 3.65
CCS Kg/pellet 240 245 242
Green pellet weight grams 1000 1000 1000
Fired pellet weight grams 859 868 874
Pellet quantity Gain % - +1 +1.75
Table 3:
According to the data in Table 3, the pellets prepared from the compositions B and C showed gain in pellet weight of about 1% and about 1.75% respectively while also showing improved cold compressive strength (CCS) when compared to the pellets prepared from the composition-A.

Example 2: Preparing iron ore pellet in commercial pellet plant
Commercial pellet plant with annual capacity of 6 million tonnes with dry grinding facility was employed for pellet preparation. The plant has two streams of dryer each of capacity 550 tph followed by ball mills.
i. Trial case with iron ore sinter fines- Predetermined proportions of iron ore fine, olivine and anthracite coal were charged to ball mill through dryer and 10% iron ore sinter fines were added bypassing the dryer directly into the ball mill. The ground material was mixed with bentonite, followed by mixing with water in an intensive mixer to get green mix material. The obtained green mix material was pelletized in pelletizing disc and green pellet balls were screened for getting pellets in size ranging from 6 mm to 16 mm. The screened pellet balls were indurated (heated) in a straight grate induration furnace of grate area of about 768 m2 at a temperature of about 1320 ºC under oxidizing atmosphere.

ii. Base case without addition of iron ore sinter fines- Predetermined proportions of iron ore fine, limestone, olivine and anthracite coal were charged to ball mill through dryer. The ground material was mixed with bentonite, followed by mixing with water in an intensive mixer to get green mix material. The obtained green mix material was pelletized in pelletizing disc and green pellet balls were screened for getting pellets in size ranging from 6 mm to 16 mm. The screened pellet balls were indurated (heated) in a straight grate induration furnace of grate area of about 768 m2 at a temperature of about 1320 ºC under oxidizing atmosphere.

Table 4 provides the results from the trial case and base case.
Parameters UoM Base case Trial case
Dryer feed rate Tph 1100 1100
Limestone rate Kg/t 22 0
Olivine rate Kg/t 40 36
Ball Mill feed rate Tph 1023 1133
Gain in feed rate % - 10.7
Green ball moisture % 8.5 8.6
Productivity GB/hour 1104 1223
Productivity gain % - 10.7
CCS Kg/pellet 210 211
Mean size Mm 11.93 12.02
TI (% of +6.3mm) 95.1 95.07
Al (% of -0.5mm) 4.5 4.7
RDI % 4 5
Table 4:
According to the data in Table 4, in the trial case, it can be observed that with addition of iron ore sinter fines, ball mill grinding capacity was increased at least 10%. The trial case showed a significant increase in pellet productivity with reduction in olivine consumption and without limestone addition/use.

Example 3: Iron ore pellet preparation using iron ore fines having moisture content of 7.03 and 8.54.
Case 1 and Case 2 experiments were carried out without use of iron ore sinter fines. Case 3 experiment was carried out with 10% iron ore sinter fines.

Case 1: Iron ore fines having moisture content of 7.03.
Predetermined proportions of iron ore fine, limestone, olivine and anthracite coal were charged to ball mill through dryer. The ground material was mixed with bentonite, followed by mixing with water in an intensive mixer to get green mix material. The obtained green mix material was pelletized in pelletizing disc and green pellet balls were screened for getting pellets in size ranging from 6 mm to 16 mm. The screened pellet balls were indurated (heated) in a straight grate induration furnace of grate area of about 768 m2 at a temperature of about 1320 ºC under oxidizing atmosphere.

Case 2: Iron ore fines having moisture content of 8.54.
Predetermined proportions of iron ore fine, limestone, olivine and anthracite coal were charged to ball mill through dryer. The ground material was mixed with bentonite, followed by mixing with water in an intensive mixer to get green mix material. The obtained green mix material was pelletized in pelletizing disc and green pellet balls were screened for getting pellets in size ranging from 6 mm to 16 mm. The screened pellet balls were indurated (heated) in a straight grate induration furnace of grate area of about 768 m2 at a temperature of about 1320 ºC under oxidizing atmosphere.

Case 3: Iron ore fines having moisture content of 8.54.
Predetermined proportions of iron ore fine, olivine and anthracite coal were charged to ball mill through dryer and 10% iron ore sinter fines were added bypassing the dryer directly into the ball mill. The ground material was mixed with bentonite, followed by mixing with water in an intensive mixer to get green mix material. The obtained green mix material was pelletized in pelletizing disc and green pellet balls were screened for getting pellets in size ranging from 6 mm to 16 mm. The screened pellet balls were indurated (heated) in a straight grate induration furnace of grate area of about 768 m2 at a temperature of about 1320 ºC under oxidizing atmosphere.
Table 5 provides results from the experiments conducted under Cases 1 to 3.
Parameters UoM Case 1 Case 2 Trial case
Iron ore moisture % 7.03 8.54 8.54
Dryer feed rate Tph 970 920 920
Iron ore Sinter fines Tph - - 90
Ball Mill feed rate Tph 900 837 931
Pellet Production Tph 747 700 773
Change in production % (-)6 (+)4
CCS Kg/pellet 220 245 219
Table 5:
According to the data in Table 5, in Cases 1 and 2- with increase in iron ore moisture content from 7.03 to 8.54, the dryer feed rate dropped by 50 tph and this resulted in a drop of 6% in pellet production rate. On the contrary, in Case 3- use of iron ore sinter fines at the rate of 90 tph, i.e., about 10% of dryer feed rate, pellet production rate was increased by 4% despite increase in the moisture content in the iron ore fines.

Claims:We Claim:
1. A Pellet composition comprising iron ore fines, carbonaceous material, binder, iron ore sinter fines and fluxing agent, optionally along with calcium oxide source.
2. The composition as claimed in claim 1, wherein the composition comprises iron ore fines, carbonaceous material, binder, iron ore sinter fines and fluxing agent.
3. The composition as claimed in claim 1, wherein the composition comprises iron ore fines, carbonaceous material, binder, iron ore sinter fines, fluxing agent and calcium oxide source.
4. The composition as claimed in claim 1, wherein the carbonaceous material is selected from a group comprising coke breeze, nut coke, anthracite coal, CDQ dust, GCP sludge, flue dust and combinations thereof.
5. The composition as claimed in claim 1, wherein the binder is selected from a group comprising bentonite, micro silica, fly ash and combinations thereof.
6. The composition as claimed in claim 1, wherein the fluxing agent is selected from a group comprising dolomite, olivine, wollastonite, pyroxenite, peridotite and combinations thereof.
7. The composition as claimed in claim 1, wherein the calcium oxide source is selected from a group comprising limestone, calcined lime, hydroxide lime and combinations thereof.
8. The composition as claimed in claim 1, wherein about 25% to 30% of the composition has particle size of less than 10 microns; about 55% to 65% of the composition has particle size of less than 45 microns; and about 88% to 95% of the composition has particle size of less than 150 microns.
9. The composition as claimed in claim 1, wherein the iron ore fines is in an amount ranging from about 80% to 95%.
10. The composition as claimed in claim 1, wherein the carbonaceous material is in an amount ranging from about 1% to 10%.
11. The composition as claimed in claim 1, wherein the binder is in an amount ranging from about 0.1% to 1.5%.
12. The composition as claimed in claim 1, wherein the iron ore sinter fines is in an amount ranging from about 3 wt % to 25 wt%.
13. The composition as claimed in claim 1, wherein the fluxing agent is in an amount ranging from about 1wt% to 10wt%.
14. The composition as claimed in claim 1, wherein the calcium oxide source is in an amount ranging from about 1wt%to 10wt%.
15. The composition as claimed in claim 1, wherein the iron ore sinter fines comprises total iron (Fe (t)) ranging from about 45 wt% to 60 wt%, ferrous oxide (FeO) ranging from about 7 wt% to 14 wt%, calcium oxide (Cao) ranging from about 9 wt% to 14 wt%, magnesium oxide (MgO) ranging from about 1.5 wt% to 2.5 wt%, aluminum oxide (Al2O3) ranging from about 1.5 wt% to 3 wt% and silicon dioxide (SiO2) ranging from about 2.5 wt% to 5 wt%; wherein Loss on ignition (LOI) of the iron ore sinter fines is Zero; and wherein moisture content of the iron ore sinter fines is zero.
16. A method for preparing iron ore pellet, said method comprising:
- preparing the composition as claimed in claim 1; and
- adding solvent to the composition and preparing pellet, followed by heating the pellet to obtain the iron ore pellet.
17. The method as claimed in claim 16, wherein the composition is prepared by steps comprising:
- mixing the iron ore fines, the carbonaceous material, the fluxing agent, optionally along with the calcium oxide source to obtain a mixture, followed by drying the mixture;
- adding the iron ore sinter fines to the dried mixture, followed by milling; and
- adding the binder to the milled mixture to obtain the composition.
18. The method as claimed in claim 16, wherein the preparing pellet comprises pelletizing mixture of the solvent and the composition to obtain the pellet having size ranging from about 6mm to 16 mm.
19. The method as claimed in claim 16, wherein the heating is carried out under oxidizing atmosphere at a temperature ranging from about 1250 ºC to 1330 ºC.
20. The method as claimed in claim 16, wherein the solvent is water; and wherein the solvent is in an amount ranging from about 8 % to 11% per weight of the composition.
21. The method as claimed in claim 17, wherein the milled mixture has particle size ranging from about 0.045 mm to 0.15 mm.
22. The method as claimed in claim 17, wherein the iron ore fines has particle size ranging from about 0.15 mm to 10mm; wherein the carbonaceous material has particle size ranging from about 0.15 mm to 30mm; wherein the fluxing agent has particle size ranging from about 1 mm to 10mm; wherein the iron ore sinter fines has particle size ranging from about 3 mm to 5 mm; and wherein the calcium oxide source has particle size ranging from about 0.15 mm to 10mm.
23. The method as claimed in claim 17, wherein the dried mixture has moisture content ranging from about 0 to 1%.
24. An iron ore pellet comprising the composition as claimed in claim 1 or prepared according to the method as claimed in claim 16.
25. The iron ore pellet as claimed in claim 24, wherein the iron ore pellet has size ranging from about 6mm to 16mm.
26. The iron ore pellet as claimed in claim 24, wherein the iron ore pellet has cold compressive strength ranging from about 210 kg/pellet to 240 kg/pellet; the iron ore pellet has tumbler index ranging from about 92% to 96%; the iron ore pellet has reduction degradation index (RDI) ranging from about 2% to 8% and the iron ore pellet has basicity ranging from about 0.1 to 0.9.