Claims:We Claim:

1. A method for manufacture of iron ore sinter involving Iron ore sinter composition including high loss -on-ignition (LOI) iron ore following sintering process involving
said iron ore sinter composition including high loss -on-ignition (LOI) iron ore comprising:45-55% of iron ore, wherein the iron ore comprises High LOI iron ore 72-82% LOI in the range of 8-10%, 18-28% of iron ore with LOI in the range of 2-5%, 3-5% of solid fuel, wherein the solid fuel is coke breeze, fluxes, wherein the fluxes comprises 5-10% of limestone, 5-10% of dolomite, 1-3% of calcined lime and 25-40% of sinter return fines and

following carrying out the step of sintering the sinter mix granules to obtain the iron ore sinter controlling the electro static precipitator (ESP) inlet temperature set in the range of 115-130 ºC, burn through temperature attainable in the range of 300-335 ºC and with sinter machine speed in the range of 2.32-2.40 m/min.

2. The method as claimed in claim 1 comprising the following steps:
- providing of sinter mix granules comprising involving said sinter mix composition with high loss -on-ignition (LOI) iron ore comprising 45-55% of iron ore, wherein the iron ore comprises 72-82% of iron ore with LOI in the range of 8-10%, 18-28% of iron ore with LOI in the range of 2-5%, 3-5% of solid fuel, wherein the solid fuel is coke breeze, fluxes, wherein the fluxes comprises 5-10% of limestone, 5-10% of dolomite, 1-3% of calcined lime and 25-40% of sinter return fines;
- adding water into the raw materials;
- mixing the water and raw materials to obtain a mixture;
- granulating the mixture to obtain granules;
- igniting the granules; and
- there after subjecting to said step of sintering the granules to obtain the iron ore sinter, wherein the electro static precipitator (ESP) inlet temperature is set in the range of 115-130 ºC, burn through temperature is attainable in the range of 300-335 ºC and sinter machine speed in the range of 2.32-2.40 m/min, such as to achieve the iron ore sinter productivity (t/m2/day) value 38.21–38.74 t/h/m2, tumbler index value (+6.3 mm) 76.20-77.24% and mean particle size value 16.16-16.68 mm.

3. The method as claimed in anyone of claims 1 to 2, wherein the main components of the iron ore by weight percentage are as follows:55-65% of Fe, 5-10% of SiO2, 2-8% of Al2O3, 0.1-0.9% of CaO, 0.01-0.06 of MgO, 0.01-0.07% of Na2O 0.03 and 0.01-0.08% of K2O; the main components of the limestone by weight percentage are 1-3% of Fe, 1-3% of SiO2, 0.1-0.6% of Al2O3, 45-55% of CaO, 1-3% of MgO, 0.01-0.06% of Na2O, 0.01-0.08% of K2O, LOI is in the range of 35-45%, moisture is in the range of 1-4%; the main components of the dolomite by weight percentage are 1-4% of Fe, 3-7% of SiO2, 0.1-1% of Al2O3, 25-35% of CaO, 15-25% of MgO, 0.01-0.08% of Na2O, 0.09-0.1 % of K2O, LOI is in the range of 35-45%, moisture is in the range of 1-4% and the main components of the calcined lime by weight percentage are 85-95% of CaO, 1-4%of MgO, LOI is in the range of 2-8%.

4.The method as claimed in in anyone of the claims 1 to 3, wherein the moisture content in the mixture is maintained in the range of 6-9% by weight.

5.The method as claimed in anyone of the claims 1 to 4wherein the time for the granulation is controlled for a period of 4-8 min.

6. The method as claimed in anyone of the claims 1 to 5, wherein the ignition time is controlled for a period 2-5 min and at an ignition temperature of 1050±50ºC.

7. The method as claimed in anyone of the claims 1 to 6, wherein sintering of the granules is carried out at the temperatures of 1300±100ºC.

8. The method as claimed anyone of the claims 1 to 7, wherein the sintering process is accompanied by a suction treatment and the negative pressure of the suction treatment is -8 to -14 mbar.

Dated this the 21st day of September, 2020
Anjan Sen
Of Anjan Sen & Associates
(Applicant’s Agent)
IN/PA-199

, Description:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

1 TITLE OF THE INVENTION :
A METHOD OF MANUFACTURING IRON ORE SINTER USING HIGH LOSS-ON-IGNITION(LOI) IRON ORE.



2 APPLICANT (S)

Name : JSW STEEL LIMITED.

Nationality : An Indian Company incorporated under the Companies Act, 1956.

Address : JSW CENTRE,
BANDRA KURLA COMPLEX,
BANDRA(EAST),
MUMBAI-400051,
MAHARASHTRA,INDIA.




3 PREAMBLE TO THE DESCRIPTION

COMPLETE

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

FIELD OF THE INVENTION

The present invention relates to an iron ore sinter composition favouring inclusion of high loss-on-ignition (LOI) iron ore and particularly relates to the manufacturing method of iron ore sinter for blast furnace iron making using the same. More specifically, the present invention relates to a method of producing iron ore sinter involving high loss-on-ignition (LOI) iron ore used in larger proportion for iron ore sinter production, favouring improved sinter property and productivity.

BACKGROUND OF THE INVENTION

Sintering is a process by which a mixture of iron ores, fluxes and coke in predefined proportion is agglomerated to manufacture a sinter product of a suitable composition and quality. Sinter is a prepared burden which constitutes the major proportion of feed to the blast furnace. Sinter is formed when the mixture is subjected to high temperatures derived from the combustion of fuel (coke and/or coal fines) through incipient fusion of the particles possessing desired porosity and strength for handling and transportation and mechanical resistance. These sinter particles are ideal for the feeding to blast furnace for iron making.

The LOI range for the iron ore used in the sintering process is, however, limited in its lower range to produce a better sinter quality and process control. In particular iron ore having more than 5% of LOI is not amenable for sinter making because the high LOI content (i.e., essentially chemically bonded water) in iron ore adversely affect the sinter properties. The use of high LOI iron ore in sinter mix results in lower strength and higher fuel consumption.

Paper entitled “A commercial production test of iron ore sinter using high amount of pisolite ores and quality evaluation of the sinter products” published in Materials & Processing Research Center, NKK corporation kokan-cho, Fukuyama, Hiroshima-ken, 721 Japan on 7th Aug 1997.The commercial production test carried out with 40 mass% pisolite ores in raw materials resulted in formation of high quality sinter by making quasi-particle having duplex structure. They have used high (9.4%) LOI iron ore maximum up to 40% only. The reason why the tumbler index was improved by the design depends mainly on the matrix strength.

Paper entitled “Sintering Properties of Marra Mamba Iron Ores” published at Steel & Aluminum R&D Department, China Steel Corporation, Hsiao Kang, Kaohsiung 81233, Taiwan, R.O.C. In this study the iron ore that have LOI 10.51% shows sharp decline in productivity along with reduction in tumbler index (+6.3 mm)%. The mean particle size (MPS) of sinter also decreased. The solid fuel rate consumption increased with the use of increased proportion of iron ore with 10.51% LOI. Further, this iron ore presented the highest permeability in sintering, medium productivity, lowest tumbler strength, smallest size of sinter and required the highest coke rate and moisture. Comparing with the other iron ores, this iron ore made the sinter of lowest bulk density which caused the lowest tumbler strength

Paper entitled “Liquid Absorbability of limonite and its Influence on the Sinter indexes” published at University of Science and Technology Beijing, School of Metallurgical and ecological engineering. The results showed that when the proportion of iron ores with strong liquid absorbability in the nucleus of the blend increase, the sinter productivity, yield and drum strength showed a gradual decrease while the solid fuel consumption showed gradual increase respectively. When iron ores with strong liquid absorbability act as nuclei particles, the proportion of the iron ore should not be too high and the recommend amount is no more than 40%.

Paper entitled “Basic characteristics of Australian iron ore concentrate and its effects on sinter properties during the high-limonite sintering process” With increasing Ore-A (Australian iron ore concentrate) ratio, the tumbler index and the reduction index (RI) of the sinter first increase and then decrease, whereas the softening interval (?T) and the softening start temperature (T10%) of the sinter exhibit the opposite behavior the reduction degradation index (RDI+3.15) of the sinter increases linearly, but the sinter yield exhibits no obvious effects. The ore-A ratio in the high-limonite sintering process is suggested to controlled at approximately 6wt%.

Patent entitled” Production of sintered ore formed by using ore of high crystallization water as raw material” bearing application no JPH0827525A, Japan. In producing a sintered ore with high crystal water iron ore fines, a high water of crystallization iron ore fines and CaO-containing auxiliary raw material, with Fe2O3 / (CaO + Fe2O3) by weight of 85 % Or less and blended in, moisture-conditioned, pseudo-grained method of producing sintered ore of high crystal water ore as a raw material of a high water of crystallization content sintered material characterized by sintering. Furthermore, in addition to the addition of the CaO-containing auxiliary raw material, preferably a solid fuel pulverized to less particle size 125µm blending 0.1% by weight or more high crystal water iron ore fines.

Patent JP6116659A entitled “Production of sintered ore with high-goethite ore as bed” disclosed a carbonaceous material of =4mm size is added to a high- goethite ore having 4-30mm size and with the mass ratio of the combined water to iron controlled to =0.07 so that the mass ratio of the carbon in the carbonaceous material to the combined water in the iron ore is adjusted to 0.05-0.3. The obtained ore is used as the bed of a fire grate moving type sintering machine to produce a sintered ore. Consequently, more high-goethite ore can be used, resources are effectively used, and the production cost of steel is remarkably reduced.

In order to produce high quality sinter with large amount of high LOI iron ore, several studies have been conducted as mentioned above. The above processes had limitations on the part of raw materials which may pose problems to the production. However, to conserve the natural resources, the use of high LOI iron ore is established through process improvement.

OBJECT OF THE INVENTION

The major object of the present disclosure is to make use of high LOI iron ores in larger proportions in sinter making.

Another object of the present invention is to establish a suitable sintering process involving an iron ore sinter composition using high LOI iron ore.

Yet another object of the present invention is directed to said sintering process to improve the productivity and properties of sinter in spite of using high LOI iron ore in larger proportion in sinter raw mix.

SUMMARY OF THE INVENTION

The basic aspect of the present invention is directed to a method for manufacture of iron ore sinter involving iron ore sinter composition including high loss-on-ignition (LOI) iron ore following sintering process involving
said iron ore sinter composition including high loss -on-ignition (LOI) iron ore comprising: 45-55% of iron ore, wherein the iron ore comprises High LOI iron ore 72-82% LOI in the range of 8-10%, 18-28% of iron ore with LOI in the range of 2-5%, 3-5% of solid fuel, wherein the solid fuel is coke breeze, fluxes, wherein the fluxes comprises 5-10% of limestone, 5-10% of dolomite, 1-3% of calcined lime and 25-40% of sinter return fines and

following carrying out the step of sintering the sinter mix granules to obtain the iron ore sinter controlling the electro static precipitator (ESP) inlet temperature set in the range of 115-130 ºC, burn through temperature attainable in the range of 300-335 ºC and with sinter machine speed in the range of 2.32-2.40 m/min.

A further aspect of the present invention is directed to said method for manufacturing iron ore sinter comprising the following steps :Firstly, providing sinter mix composition with high loss -on-ignition (LOI) iron ore comprising by mass percentage: 45-55% of iron ore, wherein the iron ore comprises 72-82% of iron ore with LOI in the range of 8-10%, 18-28% of iron ore with LOI is in the range of 2-5%; 3-5% of solid fuel, wherein the solid fuel is coke breeze, fluxes, wherein the flux comprises 5-10% of limestone, 5-10% of dolomite, 1-3% of calcined lime and 25-40% of sinter return fines; Secondly, adding water into the raw materials; Thirdly, mixing the water and raw materials to obtain a mixture; Fourthly, granulating the mixture to obtain granules; Fifthly, igniting the granules; and Lastly, sintering the granules involving the electro static precipitator (ESP) inlet temperature set in the range of 115-130 ºC, burn through temperature in the range of 300-335 ºC and sinter machine speed in the range of 2.32-2.40 m/min, to achievethe iron ore sinter productivity (t/m2/day) value of 38.21–38.74 t/h/m2, tumbler index value (+6.3 mm) is 76.20-77.24% and mean particle size value is 16.16-16.68 mm.

A still further aspect of the present invention is directed to said method wherein the main components of the iron ore comprising by weight percentage as follows:55-65% of Fe, 5-10% of SiO2, 2-8% of Al2O3, 0.1-0.9% of CaO, 0.01-0.06 of MgO, 0.01-0.07% of Na2O and 0.01-0.08% of K2O;

the main components of the limestone by weight percentage are 1-3% of Fe, 1-3% of SiO2, 0.1-0.6% of Al2O3, 45-55% of CaO, 1-3% of MgO, 0.01-0.06% of Na2O, 0.01-0.08% of K2O, LOI is in the range of 35-45%, moisture is in the range of 1-4%;the main components of the dolomite by weight percentage are 1-4% of Fe, 3-7% of SiO2, 0.1-1% of Al2O3, 25-35% of CaO, 15-25% of MgO, 0.01-0.08% of Na2O, 0.01-0.09% of K2O, LOI is in the range of 35-45%, moisture is in the range of 1-4%;the main components of the calcined lime by weight percentage are 85-95% of CaO, 1-4%of MgO, LOI is in the range of 2-8%.

A still further aspect of the present invention is directed to said method wherein the moisture content in the mixture is maintained in the range of 6-9% by weight.

A still further aspect of the present invention is directed to said method wherein the time for the granulation is controlled for a period of 4-8 min.

A still further aspect of the present invention is directed to said method wherein the ignition time which is controlled for a period of 2-5 min and at an ignition temperature of 1050±50ºC.

A still further aspect of the present invention is directed to said method wherein the sintering of the granules is carried out at the temperature of 1300±100 ºC.

A still further aspect of the present invention is directed to said method wherein the sintering process is accompanied by a suction treatment and the negative pressure of the suction treatment is -8 to -14 mbar.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1 illustrates the flow chart for a process of manufacturing iron ore sinter by using high LOI iron ore according to present invention;

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

The accompanying figure together with the detailed description below consumption of forms part of the specification and serves to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention.

The present invention is now discussed in more detail referring to the drawings that accompany the present application. In the accompanying drawings, like and/or corresponding elements are referred to by like reference numbers.

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts.

Before describing in detail embodiments that are in accordance with the invention, it should be observed that the embodiments reside primarily for a method of manufacturing iron ore sinter with by using high LOI iron ore. In the present invention the influence of high LOI iron ore on sinter properties like productivity (t/m2/day), tumbler index (+6.3 mm) %, mean particle size, mm by optimizing process parameters like ESP inlet temp (ºC) and burn through temp (ºC) is disclosed. It has been established that by lowering the ESP inlet temp (ºC) in the range of 115-130 (ºC) and burn through temp 300-335 (ºC) we can use the high LOI iron ore upto 82% in sinter mix as compared to the sinter made from base mix prepared with normal iron ore.

The present invention relates to the production of iron ore sinter for blast furnace iron making unit was developed by using high LOI iron as raw material in sintering. The parameters like electro static precipitator (ESP) inlet temperature and burn through temperature (BTT) with high LOI iron ore as raw material in sintering resulted in production of good quality iron ore sinter required for blast furnace iron making units. The production of good quality iron ore sinter for blast furnace iron making unit was developed by using the high LOI iron ore in sinter mixture which consists of iron ore, limestone, dolomite, coke breeze, calcined lime and sinter return fines. The sintering process comprises preparation of mixture, mixing and production of granules using mixing and nodulising drum by maintain the optimum moisture, transferring of granules to sintering machine and firing of granules by applying suction pressure.

The present invention relates to a method 100 for manufacturing iron ore sinter by using high loss on ignition (LOI) iron ore which enhanced productivity (+5 mm) t/m2/day and tumbler index (+6.3 mm) % is characterized by comprising the following steps as illustrated in FIG. 1.The method 100 characterized by comprising the following steps. The sintering process begins with the preparation of mixture consists of raw materials. In step 102,the raw materials are prepared according to the following mass percentage: 45-55% of iron ore, wherein the iron ore comprises 72-82% of iron ore with LOI in the range of 8-10%, 18-28% of iron ore with LOI is in the range of 2-5%; 3-5% of solid fuel, wherein the solid fuel is coke breeze, fluxes, wherein the flux comprises 5-10% of limestone, 5-10% of dolomite, 1-3% of calcined lime and 25-40% of sinter return fines. The weight percentage of the main components of the iron ore are as follows: 55-65% of Fe, 5-10% of SiO2, 2-8% of Al2O3, 0.1-0.9% of CaO, 0.01-0.06 of MgO, 0.01-0.07% of Na2O and 0.01-0.08% of K2O. The main components of the limestone by weight percentage are 1-3% of Fe, 1-3% of SiO2, 0.1-0.6% of Al2O3, 45-55% of CaO, 1-3% of MgO, 0.01-0.06% of Na2O, 0.01-0.08% of K2O, LOI is in the range of 35-45%, moisture is in the range of 1-4%. The main components of the dolomite by weight percentage are 1-4% of Fe, 3-7% of SiO2, 0.1-1% of Al2O3, 25-35% of CaO, 15-25% of MgO, 0.01-0.08% of Na2O, 0.09-0.1% of K2O, LOI is in the range of 35-45%, moisture is in the range of 1-4%. The main components of the calcined lime by weight percentage are 85-95% of CaO, 1-4%of MgO, LOI is in the range of 2-8%.The required raw material for sintering is stored in different proportionate bins.

In step 104, the water is added into the raw materials.

In step 106, the water and raw materials are mixed to obtain a mixture. The moisture content in the mixture is in the range of 6-9% by mass. The raw material is then conveyed in required proportion to MND (Mixing and Nodulising Drum) with a common conveyor. The raw material is uniformly mixed and required amount of water is added in MND.

In step 108, the mixture is granulated to obtain granules. The time for the granulation is controlled to 4-8 min. The raw mix is then stored in raw mix hopper in sinter plant main building. Sinter machine is a series of pallets rotating between charging hopper and sinter breaker.

In step 110, the granules are ignited. The ignition time is controlled to 2-5 min and at an ignition temperature of 1050±50ºC.

Lastly, in step 112, the granules are sintered. The electro static precipitator (ESP) inlet temperature is set in the range of 115-130 ºC and burn through temperature is attainable in the range of 300-335 ºC. The sinter machine speed in the range of 2.32-2.40 m/min. The granules are sintered at the temperature of 1300±100 ºC. The sintering process accompanied by a suction treatment and the negative pressure of the suction treatment is -8 to -14 mbar.

The iron ore sinter productivity (t/m2/day) value is 38.21–38.74 t/h/m2, tumbler index value (+6.3 mm) is 76.20-77.24% and mean particle size value is 16.16-16.68 mm.

In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article or composition that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article or composition. An element proceeded by "comprises...a" does not, without more constraints, preclude the existence of additional identical elements in the process, method, article or composition that comprises the element.

In the present specification, when a part “includes” a certain component, it means that the component may further include other components, not to exclude other components, unless specifically stated otherwise.

Although not defined differently, all terms including technical terms and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to whichthe present invention pertains. Commonly used dictionary-defined terms are additionally interpreted as having meanings consistent with related technical documents and currently disclosed contents, and are not interpreted as ideal or very formal meanings unless defined.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art to which the present invention pertains can easily practice. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

In addition, unless otherwise specified, % means weight%.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below consumption of in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the embodiments allow consumption of the disclosure of the present invention to be complete, and are conventional in the art to which the present invention pertains. It is provided to fully inform the knowledgeable person of the scope of the invention, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

Thus, in some embodiments, well-known techniques are not specifically described to avoid obscuring the present invention. Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings commonly understood by those skilled in the art to which the present invention pertains.

The present invention is described further hereinafter by reference to a series of examples. Experiments that were actually performed are now described by way of following examples.

Example I: Preparation of Iron ore sinter Raw Materials for Preparation of the Iron ore sinter According to the Present Invention

The raw materials were prepared according to the following mass percentage: 45-55% of iron ore, wherein the iron ore comprises iron ore with LOI in the range of 8-10% which weight percentage was varied from 72-82%, 18-28% of iron ore with LOI is in the range of 2-5%; 3-5% of solid fuel, wherein the solid fuel is coke breeze, fluxes, wherein the flux comprises 5-10% of limestone, 5-10% of dolomite, 1-3% of calcined lime and 25-40% of sinter return fines. The weight percentage of the main components of the iron ore were as follows: 55-65% of Fe, 5-10% of SiO2, 2-8% of Al2O3, 0.1-0.9% of CaO, 0.01-0.06 of MgO, 0.01-0.07% of Na2Oand 0.01-0.08% of K2O. The main components of the limestone by weight percentage were 1-3% of Fe, 1-3% of SiO2, 0.1-0.6% of Al2O3, 45-55% of CaO, 1-3% of MgO, 0.01-0.06% of Na2O, 0.01-0.08% of K2O, LOI was in the range of 35-45%, moisture was in the range of 1-4%. The main components of the dolomite by weight percentage were 1-4% of Fe, 3-7% of SiO2, 0.1-1% of Al2O3, 25-35% of CaO, 15-25% of MgO, 0.01-0.08% of Na2O, 0.09- 0.10% of K2O, LOI was in the range of 35-45%, moisture was in the range of 1-4%. The main components of the calcined lime by weight percentage were 85-95% of CaO, 1-4%of MgO, LOI was in the range of 2-8%.These experiments were termed as expt-1, expt-1, expt-2, expt-3, expt-4, expt-5 and expt-6 that were produced with the usage of high LOI iron ore in the percentage of 72%, 74%, 76%, 78%, 80% and 82% respectively.

Example II: Preparation of Iron ore sinter Raw Materials for Preparation of the Iron ore sinter according to the Conventional Sintering Process

The raw materials were prepared according to the following mass percentage: 45-55% of iron ore comprises 100% iron ore with LOI in the range of 2-5%, 3-5% of solid fuel, wherein the solid fuel is coke breeze, fluxes, wherein the flux comprises 5-10% of limestone, 5-10% of dolomite, 1-3% of calcined lime and 25-40% of sinter return fines. The weight percentage of the main components of the iron ore were as follows: 59.92% of Fe, 4.91% of SiO2, 3.57% of Al2O3, 0.37% of CaO, 0.05% of MgO, 0.02% of Na2O 0.75% of MnO and 0.03% of K2O. The main components of the limestone by weight percentage were 1-3% of Fe, 1-3% of SiO2, 0.1-0.6% of Al2O3, 45-55% of CaO, 1-3% of MgO, 0.01-0.06% of Na2O, 0.01-0.08% of K2O, LOI was in the range of 35-45%, moisture was in the range of 1-4%. The main components of the dolomite by weight percentage were 1-4% of Fe, 3-7% of SiO2, 0.1-1% of Al2O3, 25-35% of CaO, 15-25% of MgO, 0.01-0.08% of Na2O, 0.09-0.10% of K2O, LOI was in the range of 35-45%, moisture was in the range of 1-4%. The main components of the calcined lime by weight percentage were 85-95% of CaO, 1-4%of MgO, LOI was in the range of 2-8%.

Example III: Preparation of the Iron Ore Sinter According to the Present Invention

The water was added into the raw materials as mentioned in Example 1. The water and raw materials were mixed to obtain a mixture. The moisture content in the mixture was in the range of 6-9% by mass. The mixture was granulated to obtain granules. The time for the granulation was controlled to 4-8 min. The granules were ignited. The ignition time was controlled to 2-5 min and at an ignition temperature of 1050±50ºC. The granules were sintered. The electro static precipitator (ESP) inlet temperature was set in the range of 115-130ºC, burn through temperature was attainable in the range of 300-335ºC and sinter machine speed in the range of 2.32-2.40 m/min. The granules are sintered at the temperature of 1300±100ºC. The sintering process accompanied by a suction treatment and the negative pressure of the suction treatment is -8 to -14 mbar.

Example IV: Preparation of the Iron Ore Sinter According to the Conventional Sintering Process

The water was added into the raw materials as mentioned in Example 1. The water and raw materials were mixed to obtain a mixture. The moisture content in the mixture was in the range of 6-9% by mass. The mixture was granulated to obtain granules. The time for the granulation was controlled to 4-8 min. The granules were ignited. The ignition time was controlled to 2-5 min and at an ignition temperature of 1050±50ºC. The granules were sintered. The electro static precipitator (ESP) inlet temperature was set in the range of 151-156 ºC, burn through temperature was attainable in the range of 411-433ºC and sinter machine speed in the range of 2.21 m/min. The granules are sintered at the temperature of 1300±100 ºC. The sintering process accompanied by a suction treatment and the negative pressure of the suction treatment is -8 to -14 mbar.

Example V: Iron ore sinter Properties Evaluation by Present Invention and Conventional Sintering Process
The important parameters to consider with respect to quality and iron ore sinter performance are productivity value, mean particle size, tumbler index and net sinter production by present invention and conventional sintering process as given in Table 1.

Table 1

Process for sintered iron ore Type of Iron ore in Raw Material Productivity (t/m2/day) Tumbler index, (+6.3 mm), %
ISO 3271:2015
-100 # (%) fines present in sinter mix Net sinter production with high LOI iron ore, (tons) Sinter machine speed, m/min Mean particle size, mm
Present Invention Process High LOI iron ore (8-10%) Low LOI iron ore
(2-5%)
72 28 38.21 76.20 22.60 6388 2.32 16.16
74 26 38.33 76.35 23.50 6391 2.33 16.32
76 24 38.26 76.37 24.74 6407 2.36 16.61
78 22 38.35 76.10 23.76 6440 2.39 16.43
80 20 38.74 77.24 22.30 6446 2.40 16.68
82 18 38.55 76.86 23.88 6407 2.38 16.48
Conventional Process 0 100 37.33 75.22 33.52 6191 2.21 15.91

The level of productivity increased with the use of present invention that uses high LOI iron ore as compared to conventional sintering process that uses low LOI iron ore as raw materialand its found maximum 38.74 t/m2/day with 80% high LOI iron ore.Sinter productivity greatly depends on the sinter permeability of a sinter packed bed. High LOI iron ore used in the present invention consist of less percentage of -100# iron ore fines as compared to normal iron ore which helps in formation of larger pseudo-particle in the granulation stage of the sintering process resulted in increase in productivity as compared to the conventional sintering process. Raw material with the use of high LOI iron ore has improved the tumbler index (+6.3 mm) % and its found maximum 77.24% with 80% high LOI iron ore. The high LOI iron ore produces the highest mean particle size (mm) sinter, i.e., 16.68 mm with the use 80% high LOI iron ore. The best iron ore sinter properties were observed with 80% high LOI. From the above examples on usage of increased percentage of high LOI iron ore as raw material, it is found that increasing weight percentage of high LOI iron ore from 72% to 82% as raw material has good effects on the sinter properties. The desired norms of plant operating process parameters met with reduced inlet ESP temperature and reduced burn through temp with the usage of high LOI iron ore max up to 82% in sinter mix. All these are happening due to less percentage of (-100#) is sinter mix, this will improve the sinter bed permeability which results in increased in productivity +5 mm (t/m2/day) and tumbler index +6.3 mm %.
The net sinter production (tons) 6191 in conventional sintering process to 6446 (tons) in process of present invention, also there is enhancement in sinter machine speed (m/min) from 2.21 in conventional sintering process to 2.40 in process of present invention with the use of 80% high LOI iron ore in sinter mix.