adding value to the iron ore industry and the critical
TRANSCRIPT
Adding Value to the Iron Ore Industry and the Critical Role of Bentonite
S&B Industrial Minerals SA
October 2011
Pellet Industry 2010-2015 : A Challenge
Growth: 10% Europe, N. America: 5% China: 6.5% ME : 24%
Capacity Utilisation> 95%
New capacity: 150 mil MT pellets
Decrease of lumps & good quality of fines
Decrease of Price Premium : 20 cts/dtmu instead of 50 cts/dtmu
VERY COMPETITIVE
ENVIRONMENT
Need for :
• High Productivity
• Low Production Cost
• High quality
Iron Ore Pelletizing
Ore beneficiation
Bentonite Additives silo
PELLETIZING DRUMS Screw mixer
Iron ore, conveyor belt
7-10% moisture
Pellets (green)
FIRING UNIT (INDURATION FURNACE)
Where is bentonite used in pelletizing?
Pig Iron From Iron Ore to Steel
Iron Ore Iron
Concentrate Pellets Pig Iron Steel
Bentonite
What is bentonite?
OHO Si, Al Al, Fe, Mg
exchangeable cations neutral molecules (H2O)
Tetrahedral-layer
Oktahedral-layer
Tetrahedral-layer
Interlayer
Tetrahedral-layer
d 001
Crystal structure of montmorillonite
Wet state, T<100 oC
How does Bentonite Work in Pellet?
Bentonite platelets
Magnetite grain
H
H O H
H
H O
Na +
Bentonite H
Magnetite
Dry-Fired state 100 oC < T < 300 oC
Break down of Hydrogen bonds
Ca2+ Na +
slag
Na +
Fired state 300 oC < T < 800 oC
Dehydroxylation & Oxide bonding
Dry-Fired state T > 800 oC
Collapse of bentonite. Eutectic compounds for slag bonding and pellets strength
Capillary forces pull the platelets onto the magnetite particles.
Electrostatic forces and hydrogen bonds
Ind
ura
tio
n
Ba
llin
g
Bla
st
Fu
rnace
How does bentonite influence iron pelletizing?
Pellet Properties Processing Cost
In red: what we measure in the lab for
quality comparison and value in use
BENTONITE
PROPERTIES
1. Water absorption
2. Swelling
3. Electrochemical
Properties
4. Thermal Stability
5. Chemical
Composition
(%SiO2, TiO2,
CaO, MgO,
Alkalis)
R2 = 0,8111
0
1
2
3
4
5
6
7
8
300 400 500 600 700 800
Water absorption of bentonite (%)
Gre
en
dro
p N
o
Examples of Bentonite influence - 1
R2 = 0,7174
0
1
2
3
4
5
6
7
8
300 400 500 600 700 800
Water absorption of bentonite (%)
Dry
str
en
gth
(K
g/p
)
In Balling
In Induration
Quality of bentonite is KEY.
Water absorption capacity of bentonite is considered as ONE (but not the only one) of the main quality index for bentonite.
5,300
5,400
5,500
5,600
5,700
5,800
5,900
0 2 4 6 8 10 12 14
Bentonite consumption (Kg/t)
SiO
2 (
%)
+ A
l2O
3 (
%)
In Blast
Furnace
Examples of Bentonite influence - 2
0
10
20
30
40
50
60
70
0 5 10 15 20 25 30Time (min)
Red
ucti
on
sta
te (
%)
Bentonite A
Bentonite B
•The chemical composition of bentonite influences the final products’ composition (acid gangue, oxides, alkalis etc)
•Increased reducibility of pellets affects positively productivity of Blast and DR furnaces
Temperature/ °C0 200 400 600 800 1000
heat flow cor/ µV
-40
-35
-30
-25
-20
-15
-10
-5
DTG/ %/min
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
tg cor/ %
-17.5
-15.0
-12.5
-10.0
-7.5
-5.0
-2.5
0.0
2.5Exo
Fig. : Experiment : B-03118
Mass (mg) : 64,0304-15-03 Procedure : BLANK 0/1050 C, NORMAL,He, 10C/min (Seq
1)
Atm. : He Crucible : Pt/Rh
TG-DTA 92-16
102C
233C
510C716C
893C
Montmorillonite de-hydroxylation
716oC
498oC
Bentonite A Bentonite B
Lower montmorillonite dissociation temperature indicates a lower resistance during firing (lower fired pellets strength)
Examples of Bentonite influence - 3
Temperature/ °C 100 200 300 400 500 600 700 800 900
HEAT FLOW COR/ µV
-30
-25
-20
-15
-10
-5
0
5
TG COR/ %
-17.5
-15.0
-12.5
-10.0
-7.5
-5.0
-2.5
0.0
2.5
DTG/ %/min
-1.8
-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0 Exo
Fig. : Experiment : Â-02403
Mass (mg) : 67,91 10-31-02 Procedure : BLANK 0/1050 C, NORMAL,He, 10C/min (Seq
1)
Atm. : He Crucible : Pt/Rh
TG-DTA 92-16
110C
240C 429C
448C
498C
612C
853C
BENTONITE QUALITY
key to PELLET Quality, Productivity and Cost
13% lower recirculati
on load
10% lower energy
12% lower raw
materials
30% less binder
5% higher reducibility
12% higher strength
Bentonite influence in numbers
Depending on the concentrate and the bentonite, the plant could achieve UP TO:
It makes Business
Sense to OPTIMIZE
BENTONITE per
type of concentrate
Monitor final
pellets properties
Metallurgical
and physical
properties of
fired pellets.
Bentonite Mine
R&D Lab Pellet plant
End User
(Blast Furnace)
Monitor & adjust bentonite
performance in relation to
process conditions
Bentonite consumption
Properties of wet, dry and
fired pellets
Chemistry of pellets
Drum and furnace
productivity.
Associate bentonite
with pellet properties
• Pellet properties
• Firing simulation
• Metal. properties
• Develop qualities
Select Quality
Activation
Quality control
Market-to-Mine Approach
1. By using statistical analysis of experiments:
• Reveal significant differences between qualities • Set up an empirical mathematical model.
Lab : Associate Bentonite properties with
Pelletizing Performance
2. By determining mechanisms of bentonite interactions with iron ore
Find properties of iron concentrate affecting bentonite performance in agglomeration.
Predict the bentonite’s value-in-use in the plant.
Reveal “hidden” or potential value, not readily captured in the pellet plants, e.g., bentonite contribution to % plastic deformation of pellets, bentonite resistance to water hardness etc.
1. Analyze plant data regularly and quantify statistically significant differences
5.00
6.00
7.00
8.00
9.00
10.00
0 10 20 30 40 50 60
Days
Ben
ton
ite C
on
su
mp
tio
n (
Kg
/t)
Bentonite A Bentonite B
Pellet Plant : Monitor Bentonite performance in relation to process conditions
2. Build extensive databases with plant results.
3. Use of testing protocols that ensures valid comparison between binders.
4. Launch common development projects.
Economic
impact to
pellet plants
Economic
impact to End-
user
Bunker C oil cons. Drum productivity
Raw Materials Consumption
Plant losses Fines generation
Electric energy consumption
Low temperature disintegration
Strength of pellets
Tumble index
Calculation of Total Economic Benefit
Mass and
energy balance with various
binders.
Cost data for unit operations
Benefits – losses
Calculation of net differential
Economic Value.
Conclusions
• Due to the high competitive and growth environment in the pellet industry, it makes business sense to optimize the binder’s selection
• Bentonite acts as a binder and its quality could substantially influence the financials of the pellet plant as well as that of the end – user (Blast or DRI furnace)
• En Economic Model could be used to optimize the binder’s selection and use. This model needs input from the lab and plant’s data as well as a good understanding of the pellet operations.