SAIL BOKARO

1. 1
SINTERING PLANT

2. 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. 3
TYPES OF SINTER
• NON FLUX SINTER
• FLUXED SINTER
• SELF FLUXED SINTER
• SUPER FLUXED SINTER

4. SCHEMATIC DISTRIBUTION OF THE ZONES IN CHARGE DURING SINTERING
4
ON THE SINTER STRAND
ZONE OF SINTERING
ZONE OF COMBUSTION
ZONE OF CHARGE
ZONE OF DRYING
ZONE OF
CONDENSATION
OF MOISTURE

5. 5
Material flow Diagram
Sintering Plant
Flux
Hammer
Crusher
Flux Screen
+3mm
Stock Bin &
proportioning
section
Iron Ore Fines
-3mm
Coke breeze
from C O
PMD
Hot Sinter return -5mm
Cold Sinter return
Cold Sinter return
Coke return from B F -25mm
-3mm
Fuel Storage Coke crusher
Sinter
M/c
Hot
screen SLC
Cold
screen
Sinter
to BF
-8mm
-5mm
Waste Material LD Slag, Mill Scale & Flue Dust
Coke breeze
from external
sources
Nut Coke ( 15 -25 mm)
Lime Dust

6. 6
RAW MATERIALS USED FOR SINTERING
1. Iron ore fines
2. Flux ( lime stone & dolomite )
3. Coke breeze
4. 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 )

7. 7
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 )

8. COKE CRUSHING BY FOUR ROLL CRUSHERS
8
( 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)

9. 9
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. )
+ 3m m
FLUX SCREEN (10 Nos. ) CAPACITY 150T/Hr.EACH
- 3mm TO STOCK BINS
TO H / Crs
MOTOR

10. 10
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 fines
7 – 13 07 Crushed flux ( - 3 mm )
14 – 17 04 Crushed coke ( - 3 mm )
18 01 Waste materials
19 – 20 02 Cold sinter return
21 01 Hot sinter return
22 – 23 02 Lime dust

11. 11
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.

12. 12
PROPORTIONING OF CHARGE
O/F FLUX COKE W/M S/R L/D
P. M. D. ELECTRONIC
CONVEYOR SCALES
ELECTRONIC
FEEDER
VIBRO FEEDER
A –1
CONV.
TO
S/M -1
A –3
CONV.
TO
S/M -2
A –5
CONV.
TO
S/M -3
PRIMARY
MIXING
DRUM

13. -5mm
SINGLE ROLL CRUSHER
HOT SCREEN
D/F C/S
13
RAW MIX
SRC
D/C
SHAKER GATE
RAW MIX BUNKERS
ELECTRONIC FEEDERS
BALLING DRUMS
SHUTTLE DISTRIBUTOR
CHARGE HOPPER
FURNACE
DRUM
FEEDER
SINTER MACHINE
1 2 25 26
WIND BOXES
MAIN GAS COLLECTOR
TO EXH.
TO EXH.
DUST
POCKETS
(36Nos.)
ST. LINE COOLER
COOLER BLOWERS
WATER
DRUM
COOLER
+5mm
+8mm TO BF
-8mm
TO STOCK BINS
COLD SCREEN
-5mm TO STOCK BINS (HOT SINTER RETURN)
DISC FEEDER
SINTER MACHINE PROCESS FLOW
WATER WATER
H/S
RAW MIX

14. 14
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.

15. 15
CRANES – Location & Capacity
Name 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.

16. 16
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) Sintering
v) Pelletizing.

17. 17
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.

18. 18
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.

19. 19
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.

20. 20
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.

21. 21
• i) AggAlomeDratioVn ofA finesN intoT harAd, stGrongE and iOrregFular pSoroIusN lumTps wEhicRh 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

22. 22
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.

23. Huntington & Heberlein Blast roasting Pot Vacuum Extrusion Process 23

24. Green walt Single Pan Sinter Machine Pelletizing Process 24

25. 25
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.

26. 26
MECHANISM OF SINTERING
2Fe2O3.CaO + Al2O3.SiO2 2Fe2O3 CaO.Al2O3.SiO2
(SFCA)
SILICO FERRITE OF CALCIUM
AND ALUMINIUM
2Fe2O3
SLAG BOND
2Fe2O3
2Fe2O3
Heating Cooling
Single
lump
Heating
2Fe2O3
2Fe2O3
+ CaO 2Fe2O3CaO at 12000C
CALCIUM FERRITE

27. 27

28. 28
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

29. 29
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

30. 30
SINTER PLANT FACILITIES AT
TATA STEEL
F:Sinter Plant Facilities at Tata Steel.pdf

31. 31
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

32. 32
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

33. 33
R.M.B.B.PLANT LAYOUT
WAGO
N T/H
C/S
TGH
PROP
BUILDING
ROD MILLS
CRUSHER
H/M
COKE SCREEN
FLUX
SCEEN
WOB#2
WOB#1
TBS#1
TBS#2
SP1/SP2
B/R (L&T)
B/R
(ELECON)
P
YR
DUN
Ld
Slg.
Ret. Sinter fines From
G.Fce.
IOF
LSF
RP
DF

34. 34
Material Flow at Sinter Plant

35. SINTER
STORAGE
35
Hot Return
Fines
Hearth
Layer
Sinter
Screening
Proportioning
Bins
Wate
r
Mix
er
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
Segregati
on
Chute
Doubl
e
Roll
Crusher
Cold
screen
SINTER PLANT

36. 36
OVER VIEW OF SP#3-a typical DWL Sinter
Machine

37. 37
PROGRESS OF SINTERING
COMBUSTION JONE
GREEN MIX
SINTER
SUCTION MAIN
WASTE GAS FAN
WIND BOX

38. 38
BED
HEIGHT
LEVEL SENSOR
FLAP
GATES
IGNITION
HOOD
FEDDING SYSTEM
FEED ROLL
HEARTH LAYER
GREEN-MIX
BIN
GREEN MIX
SHUTTLE CONVEYOR
THERMO-VISION
CAMERA
PROBES
HEAT TREAT
MENT HOOD
HEARTH
LAYER
BIN
CCUUTT--OOFFFF
PPLLAATTEE

39. 39
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
• PHYSICAL
1. SINTER SIZE
ANALYSIS –in terms of
Cum+10mm and -5mm
2. TUMBLER INDEX
3. SHATTER INDEX
4. RDI (Reducibility
Degradation Index)
5. RI (Reducibility Index)
6. Softening and Melting
Test (S-M)

40. 40
FACTORS AFFECTING SINTER
• (1) Size of The Charge Mix: ThQe stUrengAth oLf siIntTer iYs 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 mesh
Coke 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.

41. Parameters Controlling Sintering
41
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.

42. IMPROVEMENT IN PERFORMANCE OF
42
SINTER PLANTS
BY
INTENSIFICATION OF SINTERING
PROCESS
By
Dr M T Raju
Deputy General Manager
RDCIS
SAIL

43.  Managing the existing technologies to reach
43
designed/rated performance
Incorporation of innovations to surpass rated
capacity

44. 44
Reaching rated capacity:
1.MEN (WOMEN)
2.MATERIAL
3.MONEY
4.MINUTES

45. 45
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

46. Creative (Innovative) solutions
46
are possible by
LATERAL THINKING

47. 47
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

48. 48
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.

49. Need of Intensification of sintering
49
process
Why?
Intensification of sintering process is required
to enhance the production capacity of existing
sinter machines.
How?
Without sacrificing the quality aspects.

50. 50
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

51. Methodology of Intensification of
51
sintering process
Factors that influence sintering
1) MEN
2) MATERIALS
3) PROCESS PARAMETERS.

52. 52
MATERIALS
1) Iron ore fines size
2) Iron ore fines chemistry
3) Coke breeze
4) Calcined Lime

53. .
•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.
53
GRANULOMETRY OF IRON ORE FINES

54. EFFECT OF IRON ORE FINES SIZE ON
54
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

55. 55
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

56. 56
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.

57. 57
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.

58. 58
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.

59. 59
PRO C E S S P A R A M E T E R S
•Mixing and Balling
•Segregation of mix
•Moisture
•Ignition
•Under-grate Suction
•Preheating of sinter mix
•Use of hot air in ignition hood
•cooling

60. 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.
60

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.
61

62. Laboratory model of high speed agitating mixer
62
•
A
Lab study at RDCIS showed improvement of strength
index with reference to conventional mixer

63. 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. 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
65
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
IN
CREA SI
N
G
IN
P
R
ODUC TI
VI
T
Y,
%

66. 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. 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. 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. 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. 70
Rate
Size
BTP
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
Ignition
Water
Under grate
suction

71. RECENT TRENDS OF INTENSIFICATION OF
71
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

72. 72