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India
Iron Ore Developments – view from a growing mining and steel industry
Ashok Kumar Tata Steel
Jamshedpur, India
IRON ORE 2017 Building Resilience
24th-26th July, 2017
Perth, Australia
1
India
Iron Ore Developments – view from a growing mining and steel industry
Iron ore reserves - local demand, supply, stress
Nature of the iron ore
Alumina – a difficult chapter in Indian BF ironmaking
Beneficiation challenges
Agglomeration developments 2
Iron Ore in India, numbers
resource, reserve, spread, extraction, projection Estimated Resource,
billion t
Extractable Reserve,
billion t
Current extraction,
mtpa
Estimated domestic demand 2025
mtpa
Hematite Odisha
Jharkhand Chattisgarh
Karnataka
Goa
18 5.9 4.6 3.3 2.2 1.0
9.6
Almost all hematite
Based on a projected steel
production of 180-220 mtpa
Largely hematite, some magnetite
could come in
Magnetite Karnataka
Andhra Pradesh Rajasthan
Tamilnadu Assam + others
10.5 7.8 1.5 0.5 0.5 0.3
0.02
total
28.5 9.6 160-200 ~350
3
India major economic iron ore deposits are associated with
BIF and divided into 5 distinctive zones
Zone A Bonai Iron ore Range
Zone B: N-S trending linear belt in central India
Zone C: Bellary Hospet region
Zone D: Goa and West Maharashtra
Zone E: Magnetite deposit of Karnataka
5
Forest Map Tribal population
Iron ore rich area
Mineral rich areas overlap
with areas having :
Dense forest cover Low HDI High Tribal Population Left wing extremism
Mineral Resource – Occurrence vis-à-vis Challenges
6
Distress in Indian iron ore industry – levies
7
8
Disadvantage Indian iron ore industry – scale
250 MT
290 MT
327 MT
Total No of Mines: 9
Total No of Mines: 15
Total No of Mines: 8
Total No of Mines: 6
Total No of Mines: 7
Total No of Mines: 4
17 MT
19 MT
30 MT
~47 m3 ~400 T ~10 m3 ~100 T
1
132
311
363
2013-14 2025-26
Iron Ore Forecast in 2025 mtpa
Steel Forecast in 2025 mtpa
Supply demand balance in 2025 mtpa
87
202
233
2013-14 2025-26
@7% GDP
@8% GDP +146
+231
Required Avialble
350- 400 150-
@7% GDP
@8% GDP
-200
• From being an exporter, India could become a major Importer of iron ore ??
If iron ore mining does not step up pace ..
Will iron ore mining growth keep up with steel ?
Nature of the iron ore
• Reasonably good Fe .. 52-64 %
• Moderate silica .. 2-5%
• Relatively higher alumina .. 1.5-7 % (particularly eastern India ores)
very finely disseminated in the ore- inclusions as small as a few microns
often, incorporated into the mineral lattice – Fe atoms replaced by aluminium atoms in lattice
Nature of iron ore: First impressions can sometimes mislead why eastern India ores are more difficult
Western region ores Eastern region ores
Ore type
Grade, % Fe
Friable, Soft
52-58
Hard, Friable, Blue dust, Soft
58-65
Mineral make up
major…
minor…
Hematite, Goethite
Gibbsite, Kaolinite, Quartz
Hematite, Goethite
Gibbsite, Kaolinite, Quartz
Textural Association Gangue as void filling Gangue as very fine inclusions
Goethite is ocherous
Alumina Deportment
• Alumina mainly contributed by
Gibbsite and Kaolinite (~75%)
• Alumina contributed by Goethite is
low (~25%)
• Al substitution for Fe in Goethite
lattice is 8% max
• Alumina mainly contributed by
Goethite(~65%)
• Alumina contributed by Gibbsite
and Kaolinite (~35%)
• Al substitution for Fe in Goethite
lattice is ~ 18%
the “rising” ore quality dis-advantage
13
0
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4
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…
QIT
- Ilm
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Afr
ica
n M
ine
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-…
Al2
O3,
%
Global Iron Ore Alumina
Ind
ia ..
b
ette
r q
ual
ity
Ind
ia …
ave
rage
0
100
200
300
400
500
600
8 13 18 23
Al2O3%
Vis
cosi
ty
1330
1340
1350
1360
1370
1380
1390
1400
Liqu
idus
Tem
p(C
)
Viscosity
Liquidus Temp
Effect of alumina on viscosity and liquidus temperature BF slag alumina 15 20 % - implications
Blast furnace slag - CaO/SiO2=1 , MgO=7%, 1500 oC
constant alumina input
Liquidus ▲15 oC
Viscosity ▲ 70 cp
Slag rate ▼ 100 kg/thm
ref
14
BF slag rate vs Alumina load slag alumina = 10 % , 15 % , 20 %,
Siderar
Inland 7
Thyssen Gy Posco Nagoya
Ijmuiden
Tata
Vizag
Bokaro Bhilai
Rautaruuki
170
220
270
320
370
420
15 25 35 45 55 65 75 85
Alumina load, kg / thm
Sla
g r
ate
, kg
/ t
hm
15
25 %
Can such
slags be
made to
flow ?
-40+10 mm
2% Al2O3
Industrial Practice of Iron Ore Processing – current and proposed
Lumps
Fines Slimes
Blast furnace charge
Sinter
plant
Iron Ore (ROM)
Crushing, screening,
classification plant
Tailing
pond -10+0.15 mm
2.7 % Al2O3
-0.15 mm
~8 % Al2O3
High alumina fines and slimes
Gravity separation
Magnetic separation
Froth flotation
Selective dispersion / flocculation
Bio - beneficiation
Discover optimum beneficiation
flowsheet
Enriched low
alumina product Residual Waste
Blast furnace
charge material
Agglomeration Semi-dry disposal
Iron rich cements Waste management
strategy Value-added products eco-
friendly storage
discard Plant 1 Plant 2 Plant 3 Plant 4 Plant 5 Plant 6 Plant 7 Plant 8 Plant 9
Slime Fe (%) 52.5 56-59 58 54.3 50 55 57 45 58.42
Al2O3(%) 7.4 7-10 3-5 7-8 8 7 6-7 9 3.72
SiO2 (%) 7.8 3.7-5.5 2.5-3.5 8-9 9 6 7-8 12 4.67
Slime discard % of ROM feed
24.8 13.5 18 18 12 15 17 25 16
Nature of iron ore and processing methods high Fe discard a study across several iron ore processing plants, India
Slime Dam Slime discard
12-25% of ROM
ROM: Hematite, Fe 59-64% , Alumina 3-5%, Silica 2.5-5%
Fineness…..difficulty in conventional beneficiation
Selective Flocculation - application in slime beneficiation
… water chemistry is adjusted to flocculate or disperse a particular particle type. This
process is typically used to remove very fine gangue particles
Selective flocculation and dispersion: using surface charge of particles
• The surface charge of any particle is a function of pH
• A high pH causes surfaces to become negative
• A low pH causes surfaces to become positive
Pilot Test Results of selective flocculation at Noamundi Mines
Impeller
Stand
Bucket for thickener underflow
Bucket for Flocculant Thickener
Fig No: 6 prepared test work setup
Tank
Schematic Test work setup
Fe% Alumina% Silica%
Feed 56 6.25 6.06
Product 64 3.22 2.75
Reject 42 13.10 13.68
Results
Product Fe% ~7%
Reject Fe% ~14%
Yield ~ 63%
Results “selective flocculation” induced recovery of values from ‘slime’
Results of “selective flocculation” ~ 90% Fe recovery with only 40 % alumina reporting to concentrate
“know thy ore” – navigating ore quality effects
..Iron Ore Agglomeration
Sinter alumina: experience at Tata Steel
Lowers sinter strength Raises sinter RDI Lowers sinter size
Alumina in ore, flux, fuel Countered by
Higher heat input sintering Higher flux addition
High FeO - Less reducible sinter
Higher CaO - more slag content
Blast Furnaces
Lower productivity Higher Fuel rate
24
Alumina effects in sintering …
energy consumption ↑ sinter strength ↓
71.6
71.8
72.0
72.2
72.4
72.6
72.8
73.0
73.2
73.4
73.6
2.00 2.10 2.20 2.30 2.40 2.50 2.60
Tu
mle
r In
de
x (
+6
.3m
m,%
)
Al2O3, %
Al2O3,% vs sinter strength weekly averages
25
Ore fineness and moisture effects…
high Blaine .. Joda ore pellets .. deformed high moisture, high Blaine
normal run… Noa ore run
27
Ore characteristics beyond the chemistry of ore …mineralogy
Association of iron phase Mineral Chemical Formula
Fe2O3
FeO(OH) /
Fe2O3.H2O
Untreated Goethite Heat treated @400 C Goethite
ΔH
H20
1. Productivity
2. Heat Input
Fe2O3.H2O Fe2O3
Few of the minerals in iron ore
Hematite α-Fe2O3
Hydro hematite Fe2O3.nH2O
Maghemite γ-Fe2O3
Magnetite Fe3O4
Goethite α-FeOOH Lepidocrocite γ-FeOOH Ferrihydrite (6-line) Fe1.55O1.66(OH)1.34
Gibbsite Al(OH)3
Kaolinite Al2Si2O5(OH)4
Transformation of minerals during heating
Hematite (Fe2O3)
Magnetite (Fe3O4)
Hydro-hematite Lepidocrocite
small endothermic peak appears at about 675–680 °C
480–1000 °C exothermic, oxidation
Hematite (Fe2O3)
Gibbsite Al(OH)3
Goethite FeO(OH)
Kaolinite Al2Si2O5(OH)4
575oC
Endothermic peak due to de-hydroxilation
1000oC Exothermic peak
Mullite (2 Al2O3. SiO2)
240oC 560oC
Endothermic Boehmtite AlO(OH)
800oC
Exothermic ɣAl2O3
395oC
Endothermic Alpha Hematite (α Fe2O3)
350oC
Endothermic Gamma Hematite (ɣ Fe2O3)
400oC
Exothermic Alpha Hematite (αFe2O3)
275–450 °C Exothermic Oxidation
Thermal processing tests as a means of deciphering mineral
constituents and their behavior
Thermal Analysis (TA) - a group of techniques that study the properties of materials
as they change with temperature ... Includes several different methods. These are distinguished from one another by the property which is measured.
Thermogravimetric analysis TGA Differential scanning calorimetry DSC
weight loss curve • changes in sample composition
• thermal stability
• kinetic parameters for chemical reactions in the sample
– Measure heat absorbed or liberated during heating or cooling
DSC curve phase transitions, dehydration, gas
evolution, melting, crystallization
oxidation stability, direct measurement of heat capacity
– Measure mass change during heating or cooling
31
Thermal behavior of different pure hydrous minerals, heat absorbed as function of temperature
Goethite Hydro-hematite Gibbsite Kaolinite
Single Endothermic peak
Start decomposition at 340
deg.C
Culminates to peak around 395
Deg. C
Goethite gives alpha-hematite
on decomposition
Temp (degree Centigrade) Temp (degree Centigrade) Temp (degree Centigrade) Temp (degree Centigrade)
The grain size, purity, and physical structure are also important in determining the temperature of decomposition
Endothermic followed by
exothermic peak
Start decomposition at 300oC
Culminates to peak around 350 oC
Hydro hematite gives gamma
hematite endothermic peak
Gamma hematite transform to
alpha Hematite Exothermic
350oC 395oC
350oC 300oC 350oC
240oC
560oC
300oC
575oC
1000oC
Three endothermic peaks
Peak 1 Gibbsite decomposes
to Bohemite 6.3% weight loss
Peak 2 Remaining Gibbsite
decomposes to Bohemite,
22.3% weight loss
Peak 3 Bohemite
decomposes gamma-alumina
2
1 1
1
2
3
1
2
One endothermic peak
followed by one exothermic
peak
Peak 1 Endothermic peak
due to de-hydroxilation
Peak 2 Exothermic peak
due to mullite formation
Thermogram of Lat-3
Mineral Makeup • Goethite • Hydro Hematite • Quartz
Observations 1. Two distinctive peak one for Goethite and one for Hydro hematite 2. While they both have the same chemical composition (Fe2O3.H2O), they differ structurally in the nature of
bonding of the hydrogen atom 3. In Goethite, the hydrogen atom act as a cation between oxygen atoms and in Hydro hematite hydrogen
atom is present in discrete OH group
VIRTUAL Ore Pile: synthesis of quality and stacking data
image transmission
Iron ore pile at Noamundi – for dispatch of ore to Pellet
Plant at Jamshedpur
“virtual iron ore pile”
Prediction of chemistry, mineralogy, size – for ~ one week’s supply
time series data of: • Stacker position • Discharge tph • Ore chemistry • Ore ptl size
Use of geological models Resource estimation
Bore hole results +
other information
Ore mineralogy .. effects on pelletizing performance
y = -0.1005x + 25.462 R² = 0.1611
23
23.5
24
24.5
25
25.5
5 10 15 20 25
Gro
ss p
rod
uct
ivit
y (t
/m2
/d)
Estimated % Goethite in ore
Pellet plant weekly data Jan'13-Jan'15, Availability >85%
y = 15.111x + 709.89 R² = 0.3207
750
800
850
900
950
1000
1050
1100
1150
0 5 10 15 20 25
Hea
t in
pu
t (M
J/t)
Estimated Goethite in Ore, %
Pellet plant weekly data Jan'13-Jan'15, Availability >85%
Productivity Energy consumption
37
Data Analytics for smoothening agglomeration thinking beyond the chemistry of ore …mineralogy
Association of iron phase Mineral Chemical Formula
Fe2O3
FeO(OH) /
Fe2O3.H2O
Untreated Goethite Heat treated @400 C Goethite
ΔH
H20
Productivity
Heat Input
Fe2O3.H2O Fe2O3
Adjusting pellet induration profile – based on diagnosed ore characteristics
0 200 400 600 800 1000 1200-3
-2.5
-2
-1.5
-1
-0.5
0
Temperature, oC
Weig
ht
loss,
wt%
Different ores demand heat at characteristic temperatures
A mismatch causes deficiency or excess heat poor pellets
Adjust burner settings and process to respond to measured ore characteristics
Appropriate thermal history ensures pellet quality
India summary Iron Ore Developments – view from a growing mining and steel industry
Iron ore reserves Large hematite resource base – needs rapid development, scale and facilitation
Nature of the iron ore “sticky” alumina problem in eastern India hematite goethitic ores Magnetite potential not yet explored adequately
Alumina Continues to be a difficult chapter in Indian BF ironmaking
Beneficiation challenges Complex flowsheets – leveraging gravity, magnetic, surface forces targeting specific size fractions
appear relevant
Agglomeration developments Process interventions guided by mineralogical characterization hold promise
40
Thank you
41