1 A member of the Anglo American plc group Utilisation of the -8+5mm Sishen iron ore fraction in the...

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1

A member of the Anglo American plc group

Utilisation of the -8+5mm Sishen iron ore fraction in the Sintering process

September 2008

Andre Dippenaar

2

Introduction

Sishen mine products:

• Lump ore: -25+8mm

• Fine ore: -5mm

• Intermediate fraction: -8+5mm

3

Pilot Plant Sinter Pot tests

Bc sinter – 50% fine Thaba, 50% fine Sishen

Coarse Sinter - Half of fine Sishen replaced with coarse Sishen50% fine Thaba, 25% fine Sishen, 25% coarse Sishen

Concentrate additions – 5, 10 and 15 %

4

Experimental Procedure

Sinter spesifications% SiO2 5.2

% MgO 0.77

% FeO 8.0

Basicity %CaO/SiO2 = 2.0

5

Experimental Procedure

Sinter working procedures

Sinter outputs

Tests on sinter product

6

Results – Ore fractions used

Ore Sieve analyses

mm

Thaba fine ore

Sishen fine ore

Sishen coarse ore

Concentrate

+8 1 0 15 0 +5 21 10 73 0 +3.35 20 30 10 0

+1 27 42 1 0 +0.106 25 18 1 10 +0.045 5 0 0 46 -0.045 1 0 0 44

D50 2.94 2.76 6.72 0.08

Ore fractional Sieve analyses

05

101520253035404550

16.0

00

12.5

00

10.0

00

8.00

0

6.30

0

5.00

0

4.00

0

3.35

0

2.00

0

1.00

0

0.50

0

0.25

0

0.12

5

0.10

6

0.07

5

0.05

3

0.04

5

0.00

0

Sieve size (mm)

% o

n s

ieve

Thaba fine Sishen f ine

Concentrate ore Sishen Coarse

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Results

Identification of the different pot tests:

Fine Sishen sintersFS 0C - Base case sinter with 50% Fine Sishen and 0% ConcentrateFS 5C - Fine sinter with 45% Fine Sishen and 5% Conc.

Coarse Sishen sintersCS 0C - Coarse sinter with 25% Fine Sishen, 25% Coarse Sishen and 0% Conc.CS 5C - Coarse sinter with 20% Fine Sishen, 25% Coarse Sishen and 5% ConcCS 10C - Coarse sinter with 15% Fine Sishen, 25% Coarse Sishen and 10%

Conc.CS 15C - Coarse sinter with 10% Fine Sishen, 25% Coarse Sishen and 15%

Conc

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Results

Raw material Mixture Sieve analyses

• FS 0C – 2.5 mm• CS 0C – 3.23 mm

Mixture fractional Sieve analyses

0

5

10

15

20

25

16.0

00

12.5

00

10.0

00

8.00

0

6.30

0

5.00

0

4.00

0

3.35

0

2.00

0

1.00

0

0.50

0

0.25

0

0.12

5

0.10

6

0.07

5

0.05

3

0.04

5

0.00

0

Sieve size (mm)

% o

n s

ieve

FS 0 FS 5 CS 0 CS 5 CS 10 CS 15

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Results - Sinter Pot Tests

Sinter mixture with Thaba fines and: Fine Sishen Coarse Sishen

FS 0C (BC)

FS 5C CS 0C CS 5C CS 10C CS 15C

PRODUCTION: Prod. Rate [t/m2/24h] 39.4 39.0 43.3 42.7 41.7 39.5 Sintering rate (mm/min.) 24.9 24.6 26.4 26.0 26.4 25.0 Sinter fines ratio 1.02 1.02 0.99 1.04 1.02 1.04

Total Fuel [kg/ton sinter] 73.6 69.7 73.9 74.6 74.9 76.0

Yield 86.4 86.1 86.5 86.5 85.8 86.5 % Cake Shrinkage 12.8 10.5 10.4 9.94 9.8 10.5

SINTER SIEVE ANALYSES

+40 3.5 4.6 3.7 2.9 3.3 2.8 -40+25 3.9 5.7 4.8 5.0 4.7 4.3 -25+16 19.5 16.5 15.0 14.7 13.9 13.1 -16+12.5 14.9 14.5 14.5 14.7 13.6 14.0 -12.5+10 10.3 10.1 11.7 11.4 11.2 11.9 -10+5 23.1 22.8 26.0 26.5 27.2 27.1 -5 25.0 25.8 24.2 24.7 26.1 26.8 D50(excl. the -5mm frac.) 16.0 16.8 13.6 15.2 15.2 14.8

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Results – Production Rate

39.4

39.0

43.3

42.7

41.7

39.5

38

39

40

41

42

43

44

0 5 10 15

% Concentrate ore

Pro

du

ctio

n [

t/m

2 /24h

rs]

Fine Sishen Coarse Sishen

11

Results – Fuel Consumption

73.6

69.7

73.974.6 74.9

76.0

68

70

72

74

76

78

0 5 10 15

% Concentrate ore

Fu

el r

ate

(kg

/to

n s

inte

r)

Fine Sishen Coarse Sishen

12

Results – Cake Shrinkage

12.8

10.510.409.94 9.8

10.5

8

9

10

11

12

13

14

0 5 10 15

% Concentrate ore

Sin

ter

cake

sh

rin

kag

e (%

) Fine Sishen Coarse Sishen

13

Results – Sinter Product size

16.0

16.8

13.6

15.2 15.214.8

13

14

15

16

17

18

0 5 10 15

% Concentrate ore

Sin

ter

pro

du

ct a

vera

ge

size

(m

m)

Fine Sishen Coarse Sishen

14

Results – Physical and Metallurgical properties

Sinter mixture with Thaba fines and: Fine Sishen Coarse Sishen

FS 0C (BC)

FS 5C CS 0C CS 5C CS 10C CS 15C

PHYSICAL PROPERTIES COLD STRENGTH (ISO 3271) % +6.3 mm (TI) 78.6 76.9 78.3 78.8 76.9 77.4 % -6.3+0.5mm 17.1 18.5 17.0 17.2 18.9 18.5 % -0.5mm (AI) 4.3 4.6 4.7 4.0 4.1 4.1

METALLURGICAL PROPERTIES: RDI7: (ISO 4696) % +6.3mm 12.3 14.3 29.9 32.5 30.2 34.8 % +3.15mm 52.4 55.5 66.9 70.1 69.8 70.9 % -0.5mm 7.5 6.9 5.5 4.7 4.9 4.9

RI: (ISO 4695) %/min. 1.23 1.47 1.39 1.20 1.21 1.23

High Temperature Properties (REAS) ST (°C) 1160 1192 1082 1203 1240 1193 MT (°C) 1289 1300 1213 1290 1324 1296 DT (°C) 1289 1300 1223 1299 1324 1296 Pmax (°C) 1210 1253 1130 1276 1274 1248 Pmax (mmH2O) 359 203 307 231 201 215 Cohesive zone 130 108 131 88 84 103 Viscosity (mmH2O.°C) 655 327 572 414 357 353 Relative drip mass (%) 73.9 77.0 70.7 73.7 72.8 72.8

15

Results – Cold Strength

78.6

76.9

78.3

78.8

76.9

77.4

75

76

77

78

79

80

0 5 10 15

% Concentrate ore

TI

(+6.

3mm

fra

ctio

n)

Fine Sishen Coarse Sishen

16

Results – Hot strength +3.15 mm

52.4

55.5

66.9

70.1 69.870.9

50

55

60

65

70

75

0 5 10 15

% Concentrate ore

RD

I (+

3.15

mm

fra

ctio

n)

Fine Sishen Coarse Sishen

17

Results – Hot strength -0.5mm

7.50

6.9

5.5

4.74.9 4.9

4

5

6

7

8

9

0 5 10 15

% Concentrate ore

RD

I (-

0.5

mm

fra

ctio

n)

Fine Sishen Coarse Sishen

18

Results – Reducibility

1.23

1.47

1.39

1.20 1.21 1.23

1.0

1.1

1.2

1.3

1.4

1.5

1.6

0 5 10 15

% Concentrate ore

RI

(%/m

in)

Fine Sishen Coarse Sishen

19

Results – High temperature properties

130

108

131

8884

103

50

60

70

80

90

100

110

120

130

140

0 5 10 15

% Concentrate ore

Co

hes

ive

zon

e (°

C)

Fine Sishen Coarse Sishen

20

Results – High temperature properties

73.9

77.0

70.7

73.772.8 72.8

65

70

75

80

85

0 5 10 15

% Concentrate ore

Dri

p m

ass

(%)

Fine Sishen Coarse Sishen

21

Results – Mineralogy

Sinter mixture with Thaba fines and:

Fine Sishen Coarse Sishen FS 0C (BC)

FS 5C CS 0C CS 5C CS 10C CS 15C

Mineral Morphology Hematite relict 19.8 19.1 23.8 21.9 24.8 27.2

Hematite rhombic 11.2 9.6 4.6 6.0 10.2 8.0

Spinel 23.5 19.5 30.9 32.8 30.8 32.2

SFCA acicular 9.6 11.4 3.9 10.0 8.4 10.2

SFCA tabular (columnar) 29.0 26.3 25.3 18.2 21.0 13.4

SFCA dendritic + eutectic 4.1 7.2 4.2 7.1 1.0 5.2

Calcium silicate (Ca2SiO4) 0.1 2.8 2.7 2.9 2.8 2.0

Periclase 0.0 0.0 0.0 0.0 0.0 0.0 Glass 5.7 4.1 4.6 0.8 1.0 1.8 Total bonding phases 48.4 49.0 38.0 36.1 31.4 30.6

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Results – Mineralogy

19.819.1

23.8

21.9

24.8

27.2

15

20

25

30

35

0 5 10 15

% Concentrate ore

Re

lic

t H

em

ati

te (

%)

Fine Sishen Coarse Sishen

23

Results – Mineralogy

48.4 49.0

38.036.1

31.4 30.630

35

40

45

50

55

0 5 10 15

% Concentrate ore

Bo

nd

ing

ph

as

es

(%

)

Fine Sishen Coarse Sishen

24