Innovations in Iron and Steel

at JSW Steel Ltd

Background• Incoming iron ore fines of JSW are of wide variation in physical and chemical properties.

• The higher gangue content (Al2O3+SiO2) and the ultra fines (<150 micron)

are detrimental to agglomeration process.

• Low grade iron ore fines beneficiation to get the consistency w.r.t physical & chemical properties of iron ore fines

after mining ban at Karnataka.

• Usage of high manganese iron ore fines at Agglomeration and its impact in steel making.

• Blast furnace performance with respect to 90 percent agglomerate burden.

• Waste handling through micro pellet plant for efficient utilization in base mix.

• Usage of recovered slime through slime recovery plant in pellet making.

Source –wise Iron Ore Chemistry-Low & Medium Grade

Low Grade IOF

Medium Grade IOF

Wide variation in Chemistry

Jig and Spiral Performance

Particle size distributionJigs & Spirals

feedJigs & Spirals Conc.

Medium

grade IOF

(+1)mm 59.07 69.93

(-150) mic 9.61 5.13

Low grade

IOF

(+1)mm 59.61 60.74

(-150) mic 7.77 6.66

Medium grade IOF Low grade IOF

Jigs &

Spirals

feed

Jigs &

Spirals

Conc.

% up-gradation

Jigs &

Spirals

feed

Jigs & Spirals

Conc.% up-gradation

Fe(T) 58.59 59.34 1.28 55.73 57.89 3.88

SiO2 4.92 4.16 15.45 8.55 6.39 25.26

Al2O3 5.33 5.01 6.00 5.99 5.13 14.36

LOI 5.1 5.1 _ 5.13 4.77 7.02

Improved up-gradation in case of low grade IOF with respect SiO2 and Al2O3

Product Distribution of Low and Medium Grade IOF

Comparative Analysis- Low and Medium Grade IOF

Low Grade Medium Grade

Feed Fe 48.90 52.69

Feed SiO2 12.80 9.46

Feed Al2O3 9.76 8.21

Sinter Product Fe 57.89 59.34

Sinter Product SiO2 6.39 4.16

Sinter Product Al2O3 5.13 5.01

Pellet Product Fe 56.28 60.91

Pellet Product SiO2 10.32 5.24

Pellet Product Al2O3 4.86 3.78

Tails Fe 34.93 37.82

Improved Product grade up-gradation in case of Medium Grade Processing

Comparable product grade up-gradation of sinter fines in both cases

Raw Material Challenges in Agglomeration

• Bellary and Hospet Iron ore fines are

soft and flaky in nature with high

content of Al2O3 and SiO2

• High Super fines (<100 mesh) percentage

•Low Tumbler and flaky nature of local

lump ore is detrimental to high

productive BF.

• To minimize the lump ore dependency,

about 90 % of BF burden as

agglomerate

Impact of Calcined Lime addition in Sinter Making

Sinter productivity improves with ground Calcined lime addition (<75 micron) due to

better Quasi particle strength and Granulation of sinter green mix.

Sinter Chemistry Management at JSW

• Usage of 10 to 15 percent beneficiated sinter product in base mix preparation, lower the gangue content and

minimizes the ill effect of ultra fines (<100 mesh %)

• Usage of imported limestone and dolomite reduces the gangue content in sinter and Alkali Input to BF

• Usage of Anthracite coal as a solid fuel reduces the VM (<4, %)

• Usage of High Manganese iron ore fines in base mix blend which contain low alumina, reduces alumina in sinter

Anthracite Coal addition VS Solid Fuel VM

ESP performance improves with reduced VM in solid fuel after blending with Anthracite

Impact of High MnO IOF Usage in Sintering

• High MnO IOF reduces the sinter alumina from 5.23

% to 4.85 %

• Low alumina sinter reduces the BF slag rate from 571

Kg/thm to 544 kg/thm

• High MnO percent in sinter along with high alumina

reduces the sinter Tumbler by Index by 2.09 percent

Impact of Secondary Nodulizer in Sinter Making

• Improved Granulation during secondary Nodulizer operation leads to High Productivity with low Fan RPM

• Lower Fan RPM helps in reducing the power consumption

• Improved BTP help in achieving better sinter quality w.r.to Tumbler Index and MPS

Impact of Green Mix Carbon Percentage on Pellet Making

Green Mix

Carbon%

ranges

Green Mix

carbon,%CCS

Tumbler

Index

Abrasion

IndexRDI RDI

Unfired

%(+6.3mm)% (0.5mm)% (6.3mm)% (0.5mm)%

0.80-0.90 0.86 235 93.52 5.52 17 14 7.79

0.90-0.95 0.93 233 93.44 5.63 16 14 7.8

0.95-1.00 0.98 236 93.95 5.14 14 10 6.38

1.00-1.05 1.03 238 94.51 4.55 12 8 5.65

1.05-1.10 1.08 248 94.80 4.30 11 7 5.33

1.10-1.15 1.13 251 95.06 4.07 11 7 5.36

1.15-1.20 1.17 237 94.54 4.33 11 7 5.61

1.20-1.25 1.22 241 94.68 4.34 10 7 5.66

1.25-1.30 1.26 243 94.79 4.16 11 7 5.51

>1.30 1.38 245 94.28 4.84 12 8 5.68

1.10 to 1.15 percent green mix carbon is optimum for better pellet properties

Impact of < 45 micron Grain Size on Pellet Properties

Pellet

PropertiesUnit

Increase in (<45) mic,% in Pellet Concentrate

<55% 55-60% 60-65% 65-70% >70%

AI (-0.5mm) % 7.50 7.30 6.00 5.50 4.10

TI (+6.3mm) % 91.50 91.60 93.00 93.50 95.30

CCS Kg/pellet 216 222 235 240 283

RDI (-6.3mm) % 11.30 11.50 10.20 10.20 10.60

RDI (-0.5mm) % 7.80 8.00 6.50 6.50 3.30

RDI (-3.15mm) % 6.50 6.80 6.80 6.90 4.00

Pellet Properties significantly improves w.r.to CCS, TI and RDI

with increase of <45 micron percentage in pellet concentrate

Waste Material in Integrated Steel Plant

Unit Process By-productCalcination plant Lime fines, semi-calcined lime, lime stone undersize

Refractories plant Refractories waste

Sinter plant Electro-filter dust, air borne dust

Coke Ovens Coke breeze, coke oven gas

Pellet plant Pelletization slurry

Blast furnaces B F gas, top gas dust & sludge, cast house & bunker house dedusting,

and slag granulate

Corex Corex sludge, slag

H M desulphurisation Slag, dust

BOF steelmaking L D gas, slag, sludge, primary & secondary dedusting dust, vessel

slopping

Secondary steelmaking Slag, dust

Rolling mill Mill scale

Recycling of waste material is best method to protect Environment

which leads to cost reduction also

Waste Recycling Management at JSW

Three Major initiatives developed to utilize waste generation

Micro Pelletizing Plant Slime Recovery Plant Briquetting Plant

It process all dry waste like Bag

Filter dust, LCP dust etc in

desired proportion to meet the

base mix quality requirement

It process old dumped tailing

from tailing pond to get desired

product for pellet making.

•Reduction Specific IOF and

flux consumption at sinter plant

•Low sinter cost

•Input 46-48 % Fe upgrade to 56-

57 % Fe

•Low pellet cost

Mill scale Briquetting

• It is used in SMS as Coolant

• Low steel cost

Impact of Micro Pelletisation on Waste Consumption

Before Micro

Pellet

After Micro

Pellet

Metallurgical Waste Consumption increased from 50 kg/tons to 70 kg/tons

Major Innovative Initiative at Coke Oven

1) Usage of petroleum coke as an additives in coal blend to produce desired quality metallurgical coke

a) It helps in decreasing the coke ash by 17 percent and subsequently BF coke rate to the extent of

14kg/thm

2) Installation of Coke Dry Quenching system-Following advantage are depicted below

a) Conserve heat energy and water resources

b) Water pollution minimization in compare to Conventional quenching method

c) Reduction In CO emission.

d) Power Generation

e) Significant reduction in solid fuel consumption at Iron Making due to coke reduced and consistent

moisture compare to conventional method

Impact of Coke Moisture on BF Fuel Rate

Significant reduction in fuel rate in BF with reduced sp. Moisture input through coke

Technical Specification-Iron Making

Parameters Units CX#1 CX#2 BF#1 BF#2 BF#3 BF#4

Date of Blow in 8th Aug-99 15-Apr-01 18-Aug-04 10-Aug-06 18th Feb-09 18th July-11

Production Capacity Mtpa 0.8 0.8 0.9 1.3 3.0 3.0

Avg. Production tpd 2000 2000 2800 3625 8600 8600

Productivity (WV) t/m3/day 2.5 2.3 2.5 2.5

Working Volume m3 1107 1462 3445 3445

Inner Volume m3 1250 1681 4019 4019

No of Tuyeres no 26 26 18 20 36 36

Hearth Diameter m 7.3 7.3 8 8.4 13.2 13.2

Tap holes no. 2 2 2 2 4 4

Hot Blast Temperature oC NA NA 1050 1200 1250 1250

Stoves no. NA NA 3 3 3+1 3+1

TRT Station MWh NA NA NA NA 12.5 12.5

Milestones of JSW Iron Making

Impact of Sinter Burden on BF Productivity

Significant improvement in BF productivity after Increased sinter percentage in Burden from 50 to 80 %

Impact of Productivity on BF Fuel Rate

Reduction in Fuel rate after improved productivity with increase of sinter percentage

in BF Burden

Impact of Tap Duration/day and Slag Ratio

Improved Casting Practices through optimization of Tap Hole Diameter, Slag Ratio and

Cast Duration through in-house developed ‘Casting Model’ and ‘Slag-Balance Model’

High Slag Rate Management at BF

Increased slag rate from 380 Kg/thm to 450-550 Kg/thm due to increased sp. Alumina from from 55 Kg/thm

to 80-120 Kg/thm

Following Methodologies were adopted to optimize the process with high Slag rate operation at BF3 & BF4

• Optimizing Sinter Chemistry to minimize Raw Flux addition at Blast Furnace

• Optimizing Slag Chemistry: Al2O3 - 19.5% max., MgO – 7.5 to 8.0%, B2 – 1.05

• Stabilizing Burden descent by taking corrective and preventive measures to control Channeling and

Irregular Burden Descent.

• Optimizing Burden Distribution and blowing parameters to take care of Flooding & Loading of slag in

lower part of the furnace

Impact of Sp. Alumina and Slag Rate on Productivity

Sustained Productivity during high slag rate

Innovation in Corex Units

• Optimization of Fix-Carbon/thm from 670 to 600 kg/thm through reduction in Sp.

Oxygen from 560 to 510 Nm3/thm

•Lump Coke replaced by Nut Coke in Corex with sustainable furnace stability

resulting in low hot metal cost.

• Reduction in Fuel Rates by introduction of additional Coal Drying facility.

• Enhancement of Melting Rate through usage of Sinter fines directly into the Melter

Gasifier to negate the limitations in Reduction Shaft.

• Control of tuyere burning by optimizing the Slag Chemistry

Optimization of Carbon rate and O2 Consumption

in Corex

HMPT at JSW Vijayanagar Works

• In the present time most of the iron making units is characterized by high silicon and

phosphorous, due to poor raw material characteristics.

• Removal of these impurities increases the processing time at LD converter and ladle treatment

and No full scale hot metal pre-treatment have been proved economically successful.

• JSW Steel, Vijayanagar Works, has successfully introduced India’s first Hot Metal Pre-Treatment

(HMPT) facility.

• JSW envisaged the removal of silicon and phosphorous separately by injection of reagents, fluxes

and oxygen through two lances in the transfer ladle in a two step process.

De-Si and De-P De-S

HMPT at JSW Vijayanagar Works

Blast Furnace 2

Blast Furnace 1

COREX 2

COREX 1

De-Si

De-P

De-S

De-C

Composition Change

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0.8 1.3 1.8 2.3

Silic

on W

t%

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0.8 1.3 1.8 2.3

Silic

on W

t %

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.8 1.3 1.8 2.3

Phosphoro

us, W

t %

1st Stage De-Siliconisation 2nd Stage De-Siliconisation De-Phosphorisation

Average ∆Si = 0.2 %Average ∆P = 0.06 %

Average ∆Si = 0.4 %Average ∆P = 0 %

Average ∆Si = 0.8 %

Average ∆P = 0 %

Start End Start End Start End

• The acceptable level of drop in silicon and phosphorous levels have been optimized to keep the

treatment time minimum without affecting the temperature.

• These levels have helped in keeping the charged hot metal average silicon and phosphorous levels

lower and consistent to primary steel making.

Benefits of Pre-Treatment

• Reduction in converter tap to tap time

• Improvement in Steel Cleanliness

• Reduction in slag generation and increased recycling

Slag Splashing

Slag Splashing

Initial Refractory Thickness : 900 mm

Slag splashing is a process of coating of left over

slag on the refractory lining of the vessel

It cools, solidifies, and creates a solid layer of slag

that serves as a consumable refractory layer.

Process Optimization

Tap

Temperature

Slag Height

Initial Lance Ht Slag Characteristics

Splashing Pattern

Time of

Splashing

Innovations

Selective Splashing

To splash the areas of localized erosionTo increase the life of bottom plugs

Slag Mushrooming

• Structured methodologies has been successfully used to improve the

converter lining life.

• Slag conducive for effective coating is developed.

• Splashing parameters have been optimized.

• Innovative methods of slag mushrooming and selective splashing have been

initiated.

• Furnace availability has increased.

• Holds the national bench mark of 13771 heats

Results

LD Slag Granulation

LD Slag

• The use of blast furnace slag as a constituent of concrete, either as

an aggregate or as a cementing material, or both, is well known.

• LD slag due to its very non-uniform nature and metallic content it

was never successfully utilized in cement making.

• In recent years, processed steel slag has evolved as an alternative

construction aggregate for many specialized applications.

Iron & Steel Slag : Comparison

BF Slag

• Limestone is chemically converted in

high temperature processes (High CaO).

• Generation @ 350 kgs / tcs

• CaO – 33% ; SiO2 – 30%; FeO – 0.3%

• Low Free Lime Content

• Low iron oxide fraction

• Negligible metallic iron fraction

• Better hydraulic properties

• Granulated and used in Cement making

Steel Slag

• Limestone is chemically converted inhigh temperature processes (High CaO).

• Generation @ 200 kgs / tcs

• CaO – 45% ; SiO2 – 12%; FeO – 20%

• High Free Lime Content

• High iron oxide fraction

• High metallic iron fraction

• Poorer hydraulic properties

• Metallic part recycled; rest is dumped

LD Slag Granulation

• JSW Steel introduced India’s first LD Slag Granulation process for increasing there-cycling of LD Slag

• LD Slag Granulation involves sudden quenching, of the molten slag, leading todifferent contraction of metal and slag and results in good separation of metal andslag.

• Adequate granulation takes place and leads to good stability of the final slag.

• Process can be called as accelerated ageing process which reduces the free limecontent. Removal of free lime also confirms its volumetric stability.

• Because of rapid cooling it generates more glassy structure than the air cooled slag.

LD Slag Granulation

• Shape of the granulated slag sand is

similar to BF Slag.

• Microscopically also, BF and LD slags are

similar.

Use of Granulated LD Slag

• With the introduction of LD slag granulation, new avenues of its applications

have been identified through in-house trials and in collaboration with NCCBM

(National Council for Cement and Building Research).

• Extensive studies have been carried out at JSW confirmed following

applications.

• As Raw Material in Cement Manufacture (up to 4.25 %)

• As Performance Improver in cement making (up to 5 %)

• As Blending Materials in cement making (up to 40 %)

• As Replacement of Natural Sand in Cement Mortar (up to 100 %)

Utilization of Mill Scale Briquettes

Mill Scale Briquettes

• All Integrated steel plants generate waste oxides such as mill scale, caster scale,

CRM dust, sludge, dust etc.

• There is also environmental pressure to adopt eco-friendly strategies to reduce,

recycle and re-use their wastes.

• One way is through improvements in technology, operational practices, or

adopt/develop clean processes, or processes that do not generate the same

amount of waste.

• Requires huge investments and large design changes.

• Present industrial focus is to convert the generated wastes to usable form and

re-cycle back in the present process route.

Mill Scale Briquettes

• JSW steel is the first plant in the country and one of the very few in the world

to adopt mill scale briquetting.

• Mill scale, caster scale, CRM dust and similar high iron containing wastes are

mixed and briquetted.

• Presently mill scale briquettes are being used in both the steel making shops as

secondary coolant – replacement of Iron ore

Comparison with Iron ore

Iron Ore Mill Scale Briquettes

Fe (Total) 50 - 55 % 62 - 65 %

Silica Load 5 - 6 % 1.5 - 2.5%

Sulphur 0.03 - 0.15 % 0.05 - 0.1%

Sulphur Form In-Organic Organic

Moisture 3 - 5 % < 2%

Fines 20 - 40 % 5 - 10 %

Intangible Benefits Flame Shoot-up X

Difficult to handle in

Rainy SeasonX

Source of Hydrogen X

Red Fumes X

ID Fan Perfomance Improved

Bunker Jammng X

Summary

• JSW steel is front runner in adopting innovative and novel technologies for its

operation with wide range of raw materials.

• Continuous Innovations being carried out for sustainable growth.

• Innovation cell is created to monitor status and encourage employee.

• Innovation online portal created for logging the innovations

Thank You