1

SINTERING PLANT

2

DEFINITION OF SINTERING

Sintering is a process of agglomeration of fine mineral particles into a porous and lumpy mass by incipient fusion caused by heat produced by combustion of solid fuel within the mass itself.

3

TYPES OF SINTER

• NON FLUX SINTER

• FLUXED SINTER

• SELF FLUXED SINTER

• SUPER FLUXED SINTER

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SCHEMATIC DISTRIBUTION OF THE ZONES IN CHARGE DURING SINTERING ON THE SINTER STRAND

ZONE OF SINTERING

ZONE OF COMBUSTIONZONE OF CHARGEZONE OF DRYING

ZONE OF CONDENSATION OF MOISTURE

5

Material flow Diagram Sintering Plant

Hammer Crusher

Flux

Flux Screen

+3m

m

Stock Bin & proportioning section

Iron Ore Fines

-3m

m

Coke breeze from C O

PMD

Coke return from B F -25mmFuel Storage Coke crusher

-3m

m

Sinter

M/c

Hot screen SLC

Cold screen

Sinter to BF

-8mm

-5mm

-5mm Hot Sinter return

Cold Sinter return

Cold Sinter return

Waste Material LD Slag, Mill Scale & Flue Dust

Coke breeze from external sources

Nut Coke ( 15 -25 mm)

Lime Dust

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RAW MATERIALS USED FOR SINTERING

1. Iron ore fines2. Flux ( lime stone & dolomite )3. Coke breeze4. Waste Materials: a). Flue dust ( From Blast Furnace but added in RMHP ) b). Mill scale ( From Slabbing Mill, H.S.M.&CCS) c). L.D.Slag (From S.M.S.) d). Lime dust ( From R.M.P.)5. Sinter return ( Own generation )

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MAIN SECTIONS OF SINTERING PLANT

1. RAW MATERIAL SECTION. ( For crushing of coke and flux )

2. STOCK BINS AND PROPORTIONING SECTION ( For storing,proportioning & mixing )

3. SINTER MACHINE SECTION ( For sinter making )

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COKE CRUSHING BY FOUR ROLL CRUSHERS ( 08 Nos. CAPACITY – 16 T/Hr. EACH )MIX COKE FROM C.O. COKE RETURN FROM B.F. ( - 15mm ) ( - 25mm )

+ 15 mm TO B.F.MIXED WITH SINTER

-15 mm TO FUEL STORAGE

- 15 mm

- 3 mm-3 mm TO STOCK BINS

6 mm

2 mm

(NUT COKE SCREEN)

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FLUX CRUSHING BY HAMMER CRUSHER ( 05 Nos. CAPACITY- 250T/Hr. EACH )

+ 25mm

FLUX FROM RMHP ( + 25 mm )

HAMMER CRUSHER (36 Hammers in each Crs. in two rows. )

+ 3

m m

- 3mm TO STOCK BINS

FLUX SCREEN (10 Nos. ) CAPACITY 150T/Hr.EACH

TO

H /

Crs

MOTOR

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STOCK BINS AND PROPORTIONING SECTION

A. TO STOCK RAW MATERIALS :

There are three similar series of over head bunker and conveyors to feed three sinter machines at a time. Each series contains 23 bunkers . Materials are stored in the bunkers in following order :

BUNKER No. TOTAL BUNKER MATERIAL

1 – 6 06 Iron ore fines7 – 13 07 Crushed flux ( - 3 mm )14 – 17 04 Crushed coke ( - 3 mm )18 01 Waste materials19 – 20 02 Cold sinter return21 01 Hot sinter return22 – 23 02 Lime dust

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B. FIXING OF FEED RATE :

For sending raw mix to sinter machine for sintering, fixation of feed rate of materials is done considering capacity of the sinter machine and quality requirement of blast furnace.

Feed rate fixed is :

Iron ore fines 250 T/hr.Flux 75 T/hr.

( Feeding of Flux depends on available lime in sinter required in blast furnace.Available lime means CaO – SiO2 in sinter.)

Coke 20 T/hr.Waste materials 20 T/hr.Sinter return 60 T/hr.Lime dust 02 T/hr.

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PROPORTIONING OF CHARGE

P. M. D.ELECTRONICCONVEYOR SCALES

ELECTRONICFEEDER

VIBRO FEEDER

O/F FLUX COKE W/M S/R L/D

A –1CONV.TO S/M -1

A –3CONV.TO S/M -2

A –5 CONV.TO S/M -3

PRIMARYMIXING DRUM

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RAW MIX

SRC

D/C

D/F C/S

SHAKER GATE

RAW MIX BUNKERS

ELECTRONIC FEEDERS

BALLING DRUMS

SHUTTLE DISTRIBUTOR

FURNACE

CHARGE HOPPER

DRUMFEEDER

SINTER MACHINE

WIND BOXES

1 2 25 26

MAIN GAS COLLECTOR

TO EXH.

TO EXH.DUST POCKETS(36Nos.)

ST. LINE COOLER

COOLER BLOWERS

WATERDRUMCOOLER

-5mm

+5mm

+8mm TO BF

-8mm

TO STOCK BINS

-5mm TO STOCK BINS (HOT SINTER RETURN)

SINGLE ROLL CRUSHER

HOT SCREEN

COLD SCREEN

DISC FEEDER

SINTER MACHINE PROCESS FLOW

WATERWATER

H/S

RAW MIX

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Sinter Machine Specification for each machine

There are three Sintering machines

Length - 78 M No. of pallets - 130

Sintering area – 252M2 Bed height - 480mm

Exhauster - 02 Nos. Aspirator - 02 Nos.

Cooler – Blower- 06 Nos. Balling Drum - 02 Nos.

Drum Cooler - 01 No. Straight line Cooler - 01 No.

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CRANES – Location & CapacityName Location Tons

G/Crane Fuel Storage 10

C/Crane C/Crane Building 05

H/Crane H/Crane Building 10

S/B S/B Tops 05

A1/A2 A1/A2 Area 15

B/Drum B/Drum Area 50

Exh. Exh Buld. 50

Sinter Machine Machine Build. 30

Bay 1,4& 5 ARS 15

Bay 6 ARS 03

MDP MDP 05

JN 12 S/B Top 15

Other then these 46 nos. of Telphers are also there.

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WHAT IS AGGLOMERATION

• Agglomeration is defined as the process to prepare a suitable Blast furnace feed for smooth, proper and efficient running of the Blast furnace operation.The process of agglomeration can be classified as follows:i) Briquetting.ii) Nodulising.

• Iii)Vacuum Extrusion process.iv) Sinteringv) Pelletizing.

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ADAVANTAGES OF AGGLOMERATION

• Ability to use all kinds of Raw Materials- like iron ore fines, iron bearing waste products, flue dust, Steel plant reverts.

• It can be produced into any shapes and sizes.• It can be cured to adequate strength suiting Blast

Furnace needs.• Process designed to suitable small batch operations and

large scale operations.• Excellent blast Furnace charge material in place of

lump ore, reduces the cost of smelting of ore, increases Furnace permeability there by increasing BF productivity and lowering cost in terms of lower fuel rate.

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WHAT IS SINTER

• Sintering is the process of agglomeration of iron ore fines into a porous mass by incipient fusion heat generated within the mass itself.

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TYPES OF SINTER

• Depending upon weather bases have been incorporated in the Sinter mix, sinters are divided into three broad classes: -

(i) Non Fluxed OR ACID SINTERS: - Those where no flux is present or is added in the ore.

• (ii) BASIC SINTER OR Self Fluxing SINTER: - Those where sufficient flux has been added in the sinter mix to provide a basicity that is desired in the final slag, taking into consideration only the burden acids. An extra flux is added to the BF burden, to take care of coke ash acids.

(iii) SUPER BASIC OR SUPER FLUXED SINTER: - In these type of sinters an additional flux is added to the mix to provide for the desired final slag basicity, taking into account the acids content of both ore as well as the coke ash.

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THE NEED FOR SINTER

• (i) To utilize the fines generated during the mining operation.

•(ii) To utilize different additives like mill scale, flue dust, hearth slag etc. in an integrated steel plant.

• (iii) The need for charging prepared burden in Blast Furnaces to increase productivity and lower fuel rate.

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ADVANTAGE OF SINTER• i) Agglomeration of fines into hard, strong and irregular porous lumps which gives better bed permeability.

•ii) Elimination of 60 - 70 % of sulphur and Arsenic (if present) during sintering.

• iii) Elimination of moisture, hydrated water and other volatiles on the sinter strand with a cheaper fuel.

• iv) Increased the softening temperature and narrowing down of the softening range.

• v) As the calculation of flux takes place in sinter strand, super-fluxing saves much more coke in the furnace.

• vi) It increases the Blast Furnace productivity.•

vii) Lime rich bosh slag hinders reduction of silica, absorbs vaporized silicon and sulphur to produce low- Si, low-S iron.

• viii) Increase of sinter percentage in Blast Furnace burden, increases the permeability, hence reduction and heating rate or burden increases, so the productivity also.

• ix) Utilization of solid wastes generate within steel works

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TYPES OF SINTER MAKING PROCESS

• Huntington and Heberlein Pot Process-fpr non-Ferrous metal Industry.

• Batch Sintering-Greenwalt Single Pan Process

• Allmanns Ingenoirs Bryans Multi Pan Process

• Dwight-Lloyd Continuous Sintering Process

• Pelletizing Process- This consists of sub –operations like preparation of ore feed, balling, hardening. Shaft furnaces are used for producing small tonnages. Multiple Shafts handle larger production level.

23Huntington & Heberlein Blast roasting Pot Vacuum Extrusion Process

24Green walt Single Pan Sinter Machine Pelletizing Process

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PRINCIPLE OF THE SINTER MAKING PROCESS

• Iron one sintering is carried out by putting GREEN MIX after Mixing and Nodulizing drum (a mixture of Base mode with iron ore fines, mixed with flux, coke breeze as a solid fuel, other additions, sinter return fines, lime, moisture) over a traveling gate in form of permeable bed and permeable bed.

• The top layer of this sinter bed is heated to the sintering temp. (1200C-1300C) inside a Ignition Hood furnace. In the ignition hood the air is drawn downwards, through the grate with the help of exhaust blowers (Waste Gas Fan) connected by means of Waste gas main.

• The narrow combustion zone developed initially at the top layer by layer to the sintering level. The cold blast drawn through the bed cools the already sintered layer the thereby gets itself heated. The heat contained in the blast is utilized in drying and preheating the lower layers in the bed. In advance of combustion therefore each layer gets dried and preheated by the heat transferred from the upper combustion zones. The lower portion of the bed absorbs much of the heat in the gases.

• In the combustion zone, bonding takes place between the grains and a strong and porous aggregate is formed. The process is over when the combustion zone has reached the lowest layer of the bed. The sinter cake is thus tipped from the grate in hot condition . It is then broken, cooled in sinter cooler cold sized and sent to the Blast furnace.

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MECHANISM OF SINTERING

2Fe2O3.CaO + Al2O3.SiO2 2Fe2O3 CaO.Al2O3.SiO2

(SFCA)

SILICO FERRITE OF CALCIUM AND ALUMINIUM

2Fe2O3

SLAG BOND

2Fe2O3

2Fe2O3

Heating CoolingSingle lump

Heating2Fe2O3

2Fe2O3

+ CaO 2Fe2O3CaO at 12000CCALCIUM FERRITE

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GENERAL ARRANGEMENT OF A SINTER PLANT

• Raw material receiving and proportioning system

• Mixing and Nodulizing-moisture addition

• Charging Station-laying of Green mix on the strand

• Ignition

• Sintering Process• Sinter Discharging and Hot

breaking• Cooling of sinter in Sinter

Cooler• Treatment of Sinter in terms

of Cold crushing and sizing.• Conveying to BF stock-house• Dust treatment and Waste

Gas system with Waste Gas Fan and De-dusting Fan

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EQUIPMENTS IN SINTER PLANTS

• RAW MATERIAL BINS AND WEIGH FEEDERS

• MIXING AND NODULIZING DRUM WITH WATER INJECTION SYSTEM

• SURGE BIN-SECTOR GATES WITH SERVO DRIVES AND FEED DRUM

• IGNITION HOOD FURNACE WITH BURNERS

• SINTER MACHINE-PALLETS with GRATE BARS

• WINDBOXES WITH WASTE GAS MAIN

• SPIKE CRUSHER-WITH CRASH DECK

• DOUBLE ROLL CRUSHER

• VIBRATORY COLD SCREEN FOR HEARTH LAYER

• VIBRATORY SCREEN FOR RETURN FINES

• CONVEYORS, RECEIVING CHUTES AND TRANSFER CHUTES FOR RAW MATERIAL AND SINTER

• WASTE GAS FAN WITH LCI DRIVE

• DEDUSTING FAN FOR PLANT DEDUSTING

• ESPs• LT and HT DRIVES• PNUEMATIC ACTUATORS &

VALVES

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SINTER PLANT FACILITIES AT TATA STEEL

F:\Sinter Plant Facilities at Tata Steel.pdf

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DIFFERENT UNITS OF SINTER PLANT

• RAW MATERIAL BEDDING AND BLENDING PLANT

• SINTER PLANT 1

• SINTER PLANT 2

• RAW MATERIAL BEDDING AND BLENDING ( NEW )

• SINTER PLANT 3

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FUNCTIONS OF RMBB

• Stacking of Raw materials

• Bedding and Blending of various raw materials and other constituents of Sinter mix through proportioning

• Homogenizing the mix components for achieving consistent Sinter chemistry

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R.M.B.B.PLANT LAYOUT

WAGON

T/HC/S

TGH

PROP

BUILDING

ROD MILLS

CRUSHER

H/M

COKE SCREEN

FLUXSCEEN

WOB#2

WOB#1

TBS#1

TBS#2

SP1/SP2

B/R (L&T)B/R

(ELECON)

PYR

DUN

LdSlg.

Ret. Sinter fines From G.Fce.

IOF

LSF

RPDF

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Material Flow at Sinter Plant

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Hot Return Fines

Hearth Layer

SINTER STORAGE

Sinter Screening

Proportioning Bins

Mixer

Water

Sinter Machine

Sinter Cooler

Waste Gas Fan Waste Gas

Esp.

BF HIGH LINE

Raw Materials

Return Fines Lime Dust

Hearth Layer

Hot Air Combustion Air

Cold Return Fines

Ignition Hood

Spike Crusher

Cooler Fan

Segregation

Chute Double

Roll Crusher

Cold screen

SINTER PLANT

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OVER VIEW OF SP#3-a typical DWL Sinter Machine

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PROGRESS OF SINTERING

COMBUSTION JONE

GREEN MIX

SINTER

SUCTION MAIN

WASTE GAS FAN

WIND BOX

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BED HEIGHT

LEVEL SENSOR

FLAP GATES

IGNITION HOOD

FEED ROLL

HEARTH LAYER

GREEN-MIX BIN

GREEN MIX

SHUTTLE CONVEYOR

THERMO-VISION CAMERA

PROBES

FEDDING SYSTEM

HEAT TREAT MENT HOOD

HEARTH LAYER BIN

CUT-OFFCUT-OFF

PLATEPLATE

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QUALITY ASPECT OF SINTER-WITH RESPECT TO BLAST

FURNACES PERFORMANCE• CHEMICAL

1. Fe% in Sinter

2. CaO % in Sinter

3. SiO2 % in Sinter

4. MgO% in Sinter

5. Al2O3 % in Sinter

6. FeO % in Sinter

7. K2O % in Sinter

• PHYSICAL1. SINTER SIZE

ANALYSIS –in terms of Cum+10mm and -5mm

2. TUMBLER INDEX3. SHATTER INDEX4. RDI (Reducibility

Degradation Index)5. RI (Reducibility Index)6. Softening and Melting

Test (S-M)

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FACTORS AFFECTING SINTER QUALITY• (1) Size of The Charge Mix: The strength of sinter is directly related to the size

distribution of the charge mix. If size is large, the contact area will be less and the strength of the sinter will be low and conversely if size is too small the contact area of particles will be large and the strength will be high.

Ideal size of ore Fines -10 mm to + 100 meshCoke breeze -3.2 mm 85%Flux - - 3.2 mm 85%

(2) Fuel content: - Variation in Fuel content in Charge Mix affect the peak Temperature attained during sintering, the combustion zone will not be uniform leading to poor bed permeability, This increases return fines generation

•(3) Moisture: - The presence of moisture in the Charge mix has several advantages. It maintains proper permeability in the bed during sintering. This is beneficial from the point of view of heat transfer during sintering.

• (4) Re-circulating load or Return fines addition: - For higher output of the sinter strand the circulating load should be low. A low circulating load however, reduces the permeability of the bed. An optimum-circulating load is established for maximum output of the acceptable sinter to the Blast Furnaces.

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Parameters Controlling Sintering Process

• Fuel content for heat input

• Ignition intensity- Temperature of Ignition Hood Furnace

• Moisture content of mix to control its permeability.

• Machine speed control to obtain complete Burn through

• Return Fines Addition

• Waste Gas Temperature

• Sintering Temperature or Burn through Temperature

• Pressure drop across the Sinter Bed- Main Suction

• Bed Height

• Calcined Lime addition- to improve bed Permeability.

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IMPROVEMENT IN PERFORMANCE OF SINTER PLANTS

BYINTENSIFICATION OF SINTERING

PROCESS

By

Dr M T RajuDeputy General Manager

RDCISSAIL

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Managing the existing technologies to reach

designed/rated performance

Incorporation of innovations to surpass rated capacity

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Reaching rated capacity:

1. MEN (WOMEN)

2. MATERIAL

3. MONEY

4. MINUTES

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Surpassing rated capacity:

Creative (Innovative) solutions can only enable to surpass.

Five elements of creativity.

1. FLUENCY

2. FLEXIBILITY

3. ORIGINALITY

4. AWARENESS

5. DRIVE

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Creative (Innovative) solutions are possible by

LATERAL THINKING

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INTENSIFICATION OF SINTERING PROCESS

Sinter as a prepared burden material continues to hold its prominent position in world due to its very good metallurgical properties such as tumbling strength, reduction degradation index, reducibility index, high softening temperature and low range of softening range

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PRINCIPAL STEPS OF IRON ORE SINTERING TECHNOLOGY

• The iron ore fines , lime stone fines, dolomite fines, lime dust, metallurgical wastes and coke breeze are proportioned based on charge calculations.

• Then this mix is mixed and balled in mixing and balling drums with the addition of water and then loaded onto the pallet.

• The sinter mix undergoes ignition as well as suction is applied under the bed.

• The top layer gets ignited and sintering proceeds down wards till the end .

• The hot sinter is screened and crushed.• The hot sinter is then cooled on a cooler• The cooled sinter is screened to remove -5mm

fraction and then transported to blast furnace.

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Need of Intensification of sintering process

Why?

Intensification of sintering process is required to enhance the production capacity of existing sinter machines.

How?

Without sacrificing the quality aspects.

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What is meant by intensification?

• Accelerating sintering process for achieving higher production without deterioration in quality.

• Production = k*A*B*V*Y

k = Constant A = Sintering Area B = Bulk Density of mix V = Vertical sintering speed Y = Yield

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Methodology of Intensification of sintering process

Factors that influence sintering

1) MEN

2) MATERIALS

3) PROCESS PARAMETERS.

52

MATERIALS

1) Iron ore fines size

2) Iron ore fines chemistry

3) Coke breeze

4) Calcined Lime

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. •The granulometry of iron ore fines, used in sintering, has a great influence on sinter plant performance.

•Laboratory Experiments were conducted with different granulometry of iron ore fines to assess its influence on sinter quality and productivity.

•The upper size of the iron ore fines was reduced in each of the experiments.

GRANULOMETRY OF IRON ORE FINES

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EFFECT OF IRON ORE FINES SIZE ON

SINTERING

Sl.No Size Lime %yield VSS Prod. T.I (mm) (Kg/t) (+5mm) mm/min t/m2/h %

1 0-15 0.0 70.6 18.6 1.182 69.3

2 0-8 0.0 76.5 19.6 1.272 68.3

3 0-8 20.0 75.6 20.1 1.326 67.2

4 0-6 20.0 80.3 20.3 1.418 67.3

5 0-5 20.0 81.0 21.6 1.489 66.7

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Chemical Quality

EFFECT OF TOTAL Fe

• Results show that lower Fe grade (< 62% Fe) ores and concentrates will typically form SFCA (SiO2-Fe2O3-CaO-Al2O3) as part of the final assemblage.

• Medium grade (62-65% Fe) ores will form a mixture of SFCA and SFCA-1..

•High grade (65-68% Fe) ores will form largely SFCA-1.

• The SFCA-1 phase is the most desirable bonding phase in iron ore sinter, since microstructures composed entirely of SFCA-1 show higher physical strength and higher reducibility than microstructures composed predominantly of SFCA

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LOSS ON IGNITION

The higher LOI of iron ore fines has a detrimental effect on sinter quality and productivity

EFFECT OF Al2O3

An increase in Al2O3 % by 1 % increases the RDI value by 10%

EFFECT OF SiO2

Higher SiO2 in sinter will induce the formation of glassy phases in sinter and reduce the strength of

sinter.

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COKE BREEZE SIZE

•The required coke breeze granulometry for efficient sintering is:

+5 mm < 5 % - 3 mm = 85-90 % -0.5 mm < 15 %

•Presence of higher % of +5 mm slows down the coke breeze burning rate and thus reducing sintering rate.

• For reducing the micro-fines generation during crushing, -3 mm should be screened out before the crusher.

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CALCINED LIME

•Calcined lime is one of the best intensifier of sintering process

•Preheats the sinter mix

•Enhances balling phenomena

•Replaces raw lime stone

•Calcined lime addition @ 20kg/t was found to be optimum for SAIL sinter plants.

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PROCESS PARAMETERS

•Mixing and Balling

•Segregation of mix

•Moisture

•Ignition

•Under-grate Suction

•Preheating of sinter mix

•Use of hot air in ignition hood

•cooling

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MIXING AND BALLING REGIMES

•Generally most of the sinter plants are provided with separate mixing and balling drums. But the latest generation of sinter plants are provided with a combined mixing and balling drums.

•The main purpose of mixing drum is to homogenize the sinter mix . The diameter of the drum , the RPM and the space factor play a major role in achieving higher degree of mixing.

61

•The balling drum (Nodulising drum) ensures that fines are coated on the nuclei particles, thus produce higher size balls. This facilitates in improving the mean size of sinter mix and hence the permeability of mix. Here again the diameter , RPM and space factor play a major role in achieving higher degree of balling.

•Very little water is added in mixing drum and major quantity of water is added in the balling drum

•The amount of water added and the method of water addition in the balling drum also control the degree of balling and hence the permeability of sinter mix.

62

•

A

Laboratory model of high speed agitating mixer

Lab study at RDCIS showed improvement of strength index with reference to conventional mixer

63

MOISTURE

•As is known, faster the rate of air flow through the bed faster is the rate of sintering.

•The rate of flow of the air through the bed is controlled by the vacuum under the bed and the permeability of the bed.

64

SUCTION UNDER-GRATE

•The rate of flow of the air through the bed is controlled by the vacuum under the bed and the permeability of the bed.

•The optimization of the gas dynamics parameters of the sinter machines enables one to achieve higher under grate suction and thus substantial improvements in the techno-economic parameters of the sinter production.

65

IMPROVING IN SM PRODUCTVITY PER 10 mmwc AS A FUNCTION OF SUCTION UNDER GRATE

500 600 700 800 900 1000 110 1200 1300 1400 1500

1.2

1.0

0.8

0.6

0.4

SUCTION, mmwc

INCREASING IN PRODUCTIVIT

Y, %

66

IGNITION

•To provide the required free oxygen potential in the zones for faster burning of the fuel and also early starting of sintering.

•Oxygen enrichment in ignition hood

•To produce a strong sinter in the upper part of the layer;

67

PRE-HEATING OF SINTER MIX

•Pre-heating of sinter mix helps in reducing the ill effects of Re-condensation of moisture

•Pre-heating of sinter mix can be done by: * Addition of hot water in balling drum * Addition of steam in balling drum or raw mix hopper * Installing gas burners inside the balling drum * Adding hot return fines * Addition of calcined lime

68

HOT AIR IN IGNITION HOOD

• Hot air recovered from sinter cooler could be used in the ignition hood.

•This will help in not only saving gaseous fuel, but also increases the free oxygen potential.

69

COOLING OF SINTER

•Efficient cooling of sinter will help in improving sinter strength

•Installation of proper waste heat recovery system of cooler will help in adding hot air in ignition hood

70

Rate

SizeBTP Temp

Sinter Quality

Temp

Free O2

Potential

Top layer

Starting of sintering

Productivity

Rate

Method of Addition

Balling

Permeability

Re-condensation

Under Ignition hood

Rest of machine

Coke

Water

Under grate suction

Ignition

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RECENT TRENDS OF INTENSIFICATION OF SINTERING

• High Fe, low Al2O3 iron ore fines• Serpentine replacing dolomite• Good quality and quantity of lime addition• High Intensity mixer• Divided coke addition• Polymer addition in balling drum• Pre-heating of sinter mix• New sinter mix charging system• New ignition furnaces• Taller bed operation• Higher under grate suction• Taller bed circular coolers• Process control models

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