Claims:Claims:
1. A method (200) of preparing an iron ore pellets, the method comprising:
grinding a raw materials, the raw material comprising mixture of iron ore fines, bentonite, coal fine and a triple flux combination, the triple flux combination comprising limestone, wollastonite and olivine;
mixing the raw materials in a mixer to obtain a homogeneous mixture;
adding water to the homogeneous mixture;
preparing a pellets from the homogeneous mixture by means of a pelletizer; and
firing the pellets in an induration furnace.

2. The method as claimed in claim 1, wherein the triple flux combination is configured to be source of silica and calcium oxide for bonding the iron particles when being fired.

3. The method as claimed in claim 1, wherein water is 6-9 wt. % of feed.

4. The method as claimed in claim 1, wherein the raw material being grounded to -45 microns for 55-65 wt.%.

5. The method as claimed in claim 1, wherein the triple flux combination comprised in the ratio of 15 to 25% limestone, 15 to 25 % wollastonite and oilivine 55 to 65% (all in wt.%).

6. The method as claimed in claim 1, wherein wollastonite, limestone, and olivine are sized to 30 mm, 30mm and 10mm respectively and mixed together to form triple flux combination.

7. The method as claimed in claim 1, wherein CaO is sourced from wollastonite and limestone.
8. The method as claimed in claim 1, wherein silicate is sourced from oilivine and wollastonite.

9, The method as claimed in claim 1, wherein the pellet have strength in the range 242 to 272 kg/pellet.

10. The method as claimed in claim 1, wherein the pellet have swelling index in the range 13 to 14%.

11. The method as claimed in claim 1, wherein the pellet has Tumbler index of 95-96 %.

12. The method as claimed in claim 1, wherein the pellet has RDI of 2-4%.
, Description:CROSS-REFERENCE TO RELATED APPLICATION AND PRIORITY
[001] The present application does not claim priority from any patent application.

FIELD OF INVENTION
[002] The present disclosure in general relates to the field of flux combination in iron ore pellet. More particularly, the present subject matter relates to a method of preparation of iron ore pellet.
BACKGROUND
[003] FIG. 1 shows schematics indicating the method of production of iron ore pellets with flux combination. The schematics shows a ball mill (1) used for grinding the raw materials. Further, mixture (2) may be used to mix the raw material to obtain a homogeneous mixture. The disk pelletiser (3) may be used to form pellets and the induration furnace (4) may be used to fire the obtained pellets.
[004] Generally, pelletizing involves agglomeration of fine iron ore particles into green balls by adding some binders and fluxing agents followed by heating to a temperature of 1270-1300 ?C.
[005] Pellet quality plays a vital role in decreasing the reducing agent or fuel (i.e. coke) consumption and increasing the productivity of blast furnace. Large capacity high rate blast furnaces demand very high-quality pellets to achieve high productivity and low fuel rate (i.e. coke).
[006] Generally, quality of the pellets is measured in terms of Cold Compression Strength (CCS > 200kg/pellet), Reduction degradation index (RDI < 12%) and Softening temperature > 1150 ?C. Presence of unwanted granular materials like silica and alumina leads to formation of inferior grade iron ore fines. Due to the inferior quality of the iron ore fines formation of good quality pellets according to demand of the blast furnace is not achieved. Further, due to high alumina iron ore and high machine speed the produce pellets have low CCS (cold crushing strength).
[007] 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. Blast furnace needs pellets with CCS values in the range of 200-300 Kg/pellets.
[008] Swelling Index (SI) indicates the volume change of pellets during reduction. Higher SI of pellets reduces the strength of the pellets after their reduction and thereby causing irregularities in the blast furnace. Blast furnace needs pellets with SI in the range of 14-16 %.
[009] Tumbler Test of pellets provides a measure of the resistance of the pellets to breakage or degradation by impact and abrasion. In Tumbler test a 15 kg of 10-12.5mm pellets rotes in a drum (1m diameter, 0.5m width) for 200 revolutions with 25RPM. After revolution, the percentage of +6.3mm is the Tumbler index (TI) and percentage of -0.5mm if the abrasion index (AI) of the pellets. Pellets plants prefer pellets with >95% TI and <5% AI. The fired pellets are tested for CCS and swelling index.
[0010] It is to be noted that pellet quality plays a vital role in decreasing the reducing agent or fuel (i.e. coke) consumption and increasing the productivity of blast furnace. To improve the pellet quality, it is essential to use different fluxing agents like limestone, dolomite, magnesite, olivine etc., these fluxing agents contributes in the formation of slag bonds on firing.
[0011] On firing the pellet in an induration furnace following reactions happen as shown below:
CaCO3------ CaO+CO2
2MgOSiO2-------2 MgO+SiO2
CaO+SiO2-------CaO.SiO2 (at around 1100- 1200°C) (Calcium inosilicates or silicate bonds)
FeO + SiO2----- Fayalite (melts at 1205 C)
Fe2O3 + CaO----CaO.2Fe2O3(calcium diferrite);
CaO.Fe2O3(mono calcium ferrite); CaO.2Fe2O3( dicalcium ferrite)
CaO.Fe2O3+Al2O3+SiO2—7Fe2O3.2SiO2.3Al2O3.5CaO;/9Fe2O3·2SiO2·0.5Al2O3·5CaO (SFCA-silico ferrite of calcium and aluminum.)
[0012] The CaO.SiO2 (silicate melt) has got the property of forming bond with an iron ore particle. In fluxed pellets the bonding is achieved through silicate melt formation during induration.
[0013] With on-going efforts, many techniques have been proposed for formation of an iron ore pellet composition. The existing technique may include addition of CaO and SiO2 in the range 4-12 % on pellet quality. it is also to be observed that addition of CaO and SiO2, improves the reducibility by forming precipitated slag phases in the fired pellets. During reduction, cracks are created in the pellets. Material like MgO bearing fluxes like magnesite (MagCO3), brusite (Mg(OH)2), sea water magnesia (Mg(OH))2 and magnesia brick slag are used in pellets. The existing technologies may be more focused on high temperature and do not mention about properties at room temperature. For the Indian iron ore fines with high alumina content, use of conventional fluxes (Limestone and Olivine) may be inadequate to obtain desired strength at high machine speed.

OBJECTIVE OF THE INVENTION
[0014] The object of the present disclosure is formation of pellet using flux composition that may produce improved quality of pellets.
[0015] Another object of the present disclosure is method of production of flux composition.
[0016] Another objective of the present disclosure is to produce pellets with enhance pellet properties (Swelling index, Tumbler index and abrasion).

SUMMARY
[0017] Before the present subject of iron ore pellets with triple flux combination is described, it is to be understood that this application is not limited to a particular iron ore pellets composition and the method of producing the same, as there may be multiple possible embodiment, which are not expressly illustrated in the present disclosure. It is also to be understood that the terminology used in the description is for the purpose of describing the particular implementations, versions, or embodiments only, and is not intended to limit the scope of the present application. This summary is Provided to introduce aspects related to an iron ore pellets composition and the method of producing the same. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
[0018] In one implementation, a method of preparing iron ore pellets is disclosed. The method may include grinding a raw materials. The raw materials may include mixture of iron ore fine, a bentonite, a coal fine and a triple flux combination. Further, the triple flux combination may contain limestone, wollastonite and olivine. The method further comprises mixing a raw material in a mixer to obtain a homogeneous mixture. Further, water is added to the homogeneous mixture. The pellets may be prepared from the homogeneous mixture by means of pelletizer. Firing of pellets may be performed in a induration furnace.

Brief Description of Drawings
[0019] The foregoing detailed description of embodiments is better understood when read in conjunction with appended drawings. For the purpose of illustrating the present subject matter, an example of construction of the present subject matter is provided as figures; however, the present subject matter is not limited to the specific system and method for production of pellets with triples flux combination.
[0020] FIG. 1 illustrates schematic representation of production of iron ore pellets conventionally.
[0021] FIG. 2 illustrates method steps for production of iron ore pellets in accordance with an embodiment of the invention.
[0022] FIG. 3 illustrates SEM image of a fired pellets produced with a new flux combination.

DETAILED DESCRIPTION
[0023] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words “comprising”, “including”, “consisting”, and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. Although any composition or method of production and, similar or equivalent to those described herein may be used in the practice or testing of embodiments of the present disclosure, the exemplary, iron ore pellet composition and method of producing the iron ore pellet is now described. The disclosed iron ore pellet composition and method of producing the pellets are merely examples of the disclosure, which may be embodied in various forms.
[0024] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure of iron ore pellet composition and method of producing the pellets is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein.
[0025] The present disclosure is directed to overcome one or more limitations stated above or any other limitation associated with the conventional art. Disclosed herein is an iron ore pellet using triple flux combination and a process (200) for production of the iron ore pellet as shown in FIG. 2.
[0026] In one embodiment, the pellet is produced using mixture of iron ore fines, a bentonite, a coal fine and the triple flux combination. The triple flux combination may contain limestone, wollastonite and olivine. The raw materials are ground as shown in step 204. The raw materials is mixed in a mixer to obtain a homogeneous mixture as shown in step 208.
[0027] Further, water is added to the homogeneous mixture step 212 and mixed. The homogeneous mixer is added in a pelletizer to obtain pellets as shown in step 216. The formed pellets may be fired in an induration furnace step 220. The pelletizer can be disc or drum based.
[0028] The triple flux combination used in production of an iron ore pellets contains a source of silicate and a calcium oxide. The silica and the calcium oxide form a bond with iron particles during a firing process.
[0029] The water added to the homogeneous mixture may in 6-9% of a feed. The raw material is grounded to -45 microns for 55-65 wt.%. Formulae for wollastonite is CaO.SiO2, formulae for olivine is Mg2SiO4 and Formulae for limestone is CaCO3.
[0030] The ratio of wollastonite, limestone and olivine in the triple flux combination be 15 to 25 %, 15 to 25 %, and 55 to 65%respectively. The amount of wollastonite added for the triple flux combination is compensated from the volume of limestone used conventionally. For example, flux combination conventionally used to have limestone 40% and oilivine 60%. For the claimed composition limestone can be 20% wollastonite 20% and oilivine 60% (all in wt%). Further, the size of wollastonite, limestone and olivine may be 30mm, 30mm and 10 mm respectively and are milled to reduce the size appropriately and mixed together to form triple flux combination.
[0031] The pellets formed by the present disclosed process (200) may show strength in the range 242 to 272 Kg/pellet and the swelling index in the range 13-14%. Further, the pellet formed may have tumbler index 95-96% and RDI to be 2-4%. The said properties can be demonstrated with the help of following experimental analysis.

Experimental Analysis
[0032] The experiments were done taking into the two-flux combination (conventional one) and triple flux combination (claimed). Iron, limestone, olivine (10mm) as SiO2 source and Wollastonite (30mm) as CaO and SiO2, bentonite (75 mm) as binder and anthracite coal (30mm) as fuel may be use as a raw material (before feeding into the ball mill). Iron ore fines, Olivine and anthracite coal may be ground separately to achieve desired size for iron ore pelletising. The overall size was maintained at -45micron for 60 wt. %. The raw materials may be mixed in a turbo mixture to obtain a homogeneous mixture before pelletizing. Further, water in the range 6 to 8% may be added to the homogeneous mixture. A green pellet may be prepared by using a balling disc with a diameter of 600mm, an edge height of 200mm and a tilting angel of 45 ? at 27 rpm. Further, during the balling the green pellets may be screened with 10mm and 12.5 mm. To have size in the range 10mm to 12.5 mm. The formed pellets may be fired using an electrically heated rapid heating nabertherm furnace at the temperature of 1300 ?C. Inconel baskets may be used for firing the pellets in the rapid heating muffle furnace.
[0033] In the present experiment, the pellets with two fluxes comprise 92% iron ore fines, 0.5% bentonite, 1.2% coal fines and 2.5% limestone and olivine 3.8. Further, the pellets with three flux combination comprise 92% iron ore fines, 0.5% bentonite, 1.2% coal fines and 3.8% olivine, 1.2% limestone and 1.3% wollastonite. The pellets with two fluxes further may comprises of 40% limestone and 60% olivine, i.e., 2.5% limestone and 3.8% olivine in the iron ore pellets whereas pellets with triple flux combination may comprise 92% iron ore fines, 0.5% bentonite, 1.2% coal fines and 6.3% triple flux. Pellets with disclosed flux combination comprised 20% limestone, 20% wollastonite and 60% olivine, i.e., 1.25% limestone, 1.25% wollastonite and 3.8% olivine in the iron ore pellets.
[0034] Table 1 shows the chemical analysis of ingredients used for pellet making for the experimental analysis for Pellets with two flux combination (conventional) and Pellets with three flux combination (as claimed). The Wollastonite composition for the two flux shall be nil and rest remains the same.

Table 1
Constituents, wt.% Iron ore Bentonite Limestone Wollastonite Olivine Anthracite Coal
Fe(t) 61.25 9.72 - 0.58 4.91 0.65
SiO2 4.33 45.97 1.55 48.5 42.27 5.2
Al2O3 3.91 14.49 0.31 0.46 0.49 2.21
CaO 0.04 1.78 53.01 48 0.37 0.15
MgO 0.01 2.24 0.43 0.14 48.35 0.14
LOI 3.24 17.6 43.56 - 1.1 -
Fixed carbon - - - 86.37
[0035] Table 2 shows the particle size distribution of the materials used for pellet making for the experimental analysis. The Wollastonite composition for the two flux shall be nil and rest remains the same.

Table 2
Size range (µm) Iron ore Bentonite Wollastonite Limestone Olivine Coal
+150 7.4 19.8 8.6 19.0 10.3 18.1
-150+74 4.8 7.7 7.0 5.0 9.4 8.4
-74+63 5.7 7.7 6.4 2.9 7.3 7.2
-63+45 10.9 17.9 7.6 2.9 10.3 7.8
-45+37 3.8 9.3 7.3 2.1 9.5 6.8
-37 67.4 37.7 63.1 68.1 53.2 51.7
[0036] Further, Table 2 shows size of different materials after the materials have been ground separately in the mixture.
[0037] Following are the synopsis of the obtained pellet shown in Table 3.

Table 3
Pellets with two flux combination (conventional) Pellets with three flux combination (claimed)
Fe, % 61.42 61.52
CaO, % 1.3 1.34
SiO2, % 4.45 5.35
MgO, % 1.8 1.8
Al2O3, % 2.9 2.56
Mean size, mm 11.93 12.02
TI (% of +6.3mm) 94.80 95.07
Al(% of -0.5mm) 4.2 4.13
CCS Avg. (Kg/pellet) 229 272
RI(%) 67.49 66.96
SI (%) 17.71 13.75
[0038] Table 3: Pellet chemistry and pellet productivity before and after innovation.
[0039] Further, referring to FIG. 3, shows the surface electron micrography (SEM) image of fired pellets produce with new flux combination. The SEM image may clearly show side silicate bonds.

[0040] Table 3 shows the comparison between the claimed (with triple flux combination) and conventional (pellets with double flux combination). The pellets with triple flux combination obtained may comprises Fe(T) of 61.52 wt.% CaO of 1.34 wt.%, SiO2 of 5.35 wt%, MgO of 1.8 wt% and Al2O3 of 2.56 wt%. New flux combination used in pellet making may provide increase in silicate melt formation which helps in increasing the strength. The pellets obtained by the method described above may show increase value of CCS as 272 Kg/pellet. Further, the Swelling index obtained may be 13.75 and a Tumbler index of (+6mm) of 95.07 and abrasion index (-0.5mm) 0f 4.13.
[0041] The advantage of using the wollastonite as a source of Silicate and CaO is that during induration it can form more silicate bonds thereby increasing the strength of fired pellets. CaO is sourced from wollastonite and limestone. A silicate is sourced from oilivine and wollastonite. These silicate bonds (CaO.SiO2) are evenly distributed in between iron ore particles.
[0042] The further advantage of the flux composition is that it may capture the alumina present in high alumina iron ore to form a silico ferrite of calcium and aluminium or SFCA (as depicted in the reaction in the background) and may help in maintaining the strength during firing of a high alumina iron ore.
[0043] Further, from Table 3 shows that the use of the flux composition may increase CCS value by 43 points, swelling index may decrease by 3 points and production may improve by 3%.
[0044] In the present embodiment the usage of wollastonite in pellet making may results in formation of more silicate melt or silicate bond. Due to the increased in silicate bond width, the new fluxed pellets may exhibit good swelling index by arresting the stresses caused by phase changes and improved the strength of the pellets. The disclose fluxed pellets combination exhibited good strength (CCS= 272 kg/pellet), Lower swelling index (13.75) and high tumbler index as shown in the Table 3.
[0045] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features.
[0046] Some embodiments enable the use of wollastonite even when there is high alumina in iron ore. During induration of high alumina iron ore this wollastonite captures the high alumina and forms calcium alumino silicates.
[0047] Some embodiment may decrease the coal consumption due to low LOI as compared to limestone.
[0048] Some embodiment enable decrease in coal consumption by 25% in pellet making.
[0049] Although implementations for Triple flux combination iron ore pellets and the method of production has been described, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations for providing generating suggestions to improve network service quality.