impact of activated nut coke on energy efficiency in the blast furnace

Impact of activated nut coke on energy efficiency in the blast furnace

Lena Sundqvist kvist 1, Carina Brandell

2, Maria Lundgren

1

1Swerea MEFOS AB

Box 812, SE- 971 25 Lule, Sweden

+46 920 20 19 00

[email protected]

[email protected]

2 Luossavaara-Kiirunavaara AB (LKAB)

Box 952, SE-971 28 Lule, Sweden

+46 920 38 000

[email protected]

(Note: Please add more authors in the same format if necessary)

Keywords: Blast furnace nut coke, activation, energy efficiency, thermal reserve zone

INTRODUCTION

When the temperature in the thermal reserve zone is reduced, the equilibrium between CO/CO2 and Fe/FeO is shifted towards metallic

Fe at a specific reducing power of the gas as can be seen in Figure 1. The use of highly reactive nut coke mixed ferrous materials is

one possible method for reducing the temperature.

Figure 1 Fe-O-C equilibrium diagram including the Boudouard curve as well as the degree of reduction in the presence of CO and

CO21

In studies conducted by Nomura et al. 2, 3

it has been shown that the reactivity of coke can be increased either by adding a catalyst to

the coal blend prior coking or to treat the produced coke. Reactive coke was successfully produced by using a coal type with Ca rich

ash in the coal blend for coke making2. In laboratory testing the coke showed high chemical reaction rate with CO2 at 950 C, but the

reactivity index (CRI) increased less and the strength after reaction (CSR) could be more or less kept unchanged if the addition of the

Ca-rich coal was less than 10%. In full scale coke production 5-7% of the Ca rich coal was added. Adiabatic BF simulator trials with

sinter showed decreased thermal reserve zone temperature and higher reduction degree of sinter for the Ca-rich coke compared to

ordinary coke. The total reductant rate of the operational BF decreased when changing from ordinary coke to the Ca-rich coke. Results

were also reported from the addition of iron ore or iron oxide prior to the production of a reactive coke 4. The iron oxide caused

decreased strength after reaction and increased reactivity of the coke but the strength measured as drum index was proper. The iron

oxide has a tendency to react with the silica brick in the coke oven at temperatures of 1200C but not at a temperature of 1100C.

A catalyst can be added post coke making and deteriorating effects on strength can be avoided3. In laboratory testing it was estimated

that 70% of the addition made as a solution or slurry with a desirable composition should sustain raw material handling. The reaction

rate and the weight loss are increased with the addition of Fe and Ca containing compounds and the results indicate that the thermal

reserve zone temperature may decrease and improved reduction of ferrous material possibly be achieved. The authors think that more

studies are needed to explore and confirm the effect further.

By using a high ratio of nut coke mixed with the ferrous material the high temperature properties of the iron ore in terms of reduction

degree was improved up to 10% addition5. Improved shaft efficiency decreased reductant rate and the permeability of the cohesive

zone were stated in industrial trials charging approximately 100 kg nut coke/tHM. The reactivity of the coke is not stated but the coke

has a CaO content of 0.25 wt%.

Aiming for reduced consumption of reducing agents in the BF, the most appropriate method for activation of nut coke were analyzed

in the laboratory and later up-scaled for use in pilot scale treatment at LKAB in Malmberget. To explore the effect on the process

conditions and the energy efficiency operational trials in the LKAB experimental BF in Lule were planned and conducted. The

results from the trials are presented and discussed.

EXPERIMENTAL

The LKAB Experimental Blast Furnace (Experimental BF)

The first campaign in the Experimental BF was conducted in 1997 and these trials were conducted as one part of the 29th

campaign. It

is usually operated twice every year and the length of each campaign is approximately 6 to 8 weeks. The operation and control of the

Experimental BF are comparable with the industrial BF but the response time is shorter.

Figure 2 Schematic layout of Experimental BF plant

The Experimental BF, of which the schematic layout is shown in Figure 2, is equipped for flexibility in type of in injection and

process settings. The plant is compact and all equipment is installed in a single building. The raw material handling allows the usage

of up to four different ores simultaneously. Injection of pulverized coal, gas or oil is possible, as well as injection of fluxes or other

oxides.

Table I Positions for installed measurements used in the evaluation of data

Type of equipment Position below stockline Position on radius

Blast furnace burden level 0

Upper skinflow -0.44 30 , 90 ,150 ,210 , 270 , 330

Upper shaft probe -0.90 From 30 to 150 , 9 positions

Lower skinflow -1.05 30 , 90 ,150 ,210 , 270 , 330

Lower shaft probe -3.46 From 30 to 150 , 9 positions

Inclined shaft probe -4.21 From 210 to 0

Tuyeres -5.7 30 , 150 , 270

The Experimental BF is also well-equipped for measuring of temperature and pressures. The shaft has no water cooling,

thermocouples are installed inside the refractory and pressure measurements over the height of the shaft. In order to study the

atmosphere inside the shaft and collect material samples during operation, material and gas/temperature probes are fitted to the blast

furnace, as shown in Figure 3.

Figure 3 The Experimental BF including shaft probes, inclined probe and vertical probe

The vertical temperature profile of the Experimental BF can be measured by inserting a thermocouple from the top allowing it to

descend with the burden. This measurement normally withstands temperatures up to approximately 1250C before the thermocouple is

damaged. The levels where thermocouples and other important blast furnace equipment have been installed are listed in Table I and

the radial sampling and measurements with probes are shown in Figure 4.

Figure 4 Radial position of lower shaft and inclined probes

Raw Materials

The ferrous burden for all periods was LKAB olivine pellets from Malmberget. Quartzite was added to reach the desired slag volume

and a limestone and BOF slag was used for basicity adjustment of the final slag. The chemical compositions of raw materials,

including the activated coke, are given in Table II.

Nut coke and coke used in the coke layers were crushed and screened into the fraction 15-30 mm. Three types of treatments were used

for nut coke to be added to ferrous layers; a solution with Zr-tracer, a slurry of magnetite with Zr-tracer and a slurry of burnt lime with

Zr-tracer. The solutions and slurries were sprayed on the coke under rotation in a drum (left photo in Figure 5) and finally the coke

was dried (right photo in Figure 5) and samples for analyses taken before transportation to the Experimental BF plant.

Figure 5 Processes of preparation of activated nut coke by coating and drying of coated coke afterwards

The original nut coke used as well as the Zr-traced one has similar chemical composition as the coke used in the coke layers. As the

activated coke was coated with slurries of magnetite or hydrated lime the chemical composition was changed somewhat. The content

of C was lowered at the same time as either the content of Fe or CaO increased. The slurries also contained zirconium sulphate for

tracing the activated nut coke in samples collected during the trials.

Figure 6 Moisture content in coke and nut coke used during the Experimental BF tests

Samples of raw materials were collected every time the raw material bins were filled up. Moisture content of coke and ferrous material

as well as the particle size distribution of pellets were analyzed for each sample. In case of changed moisture content to a new stable

level the new values were introduced in the system and used in the recipe calculations. The variation in measured moisture content of

pellets was minor and the variation in coke moisture is shown in Figure 6. To minimize the variations in coke moisture one single

delivery of coke was used during the trial and in general the moisture was in the range of 4-6%. However, a few significant changes in

moisture was experienced although this precaution. The lime coated coke had lower moisture content compared to the other coke

types due to longer time for drying after coating.

0

2

4

6

8

10

12

14

13-05-01 00:00 13-05-06 00:00 13-05-11 00:00 13-05-16 00:00 13-05-21 00:00 13-05-26 00:00

% m

ois

ture

Large sample Small sample

Zr Large Zr small

Lime large Lime small

Magnetite large Magnetite small

Lime coated coke

Table II Raw materials used during the trial and their composition, given in wt.-%

MPBO Limestone Quartzite

BOF

slag

Nut coke

Coke PC

Lime

activated

Magnetite

activated

Original &

Zr-traced

CaO 0.43 58.0 0.199 40.5 1.30 0.03 0.03 0.03 0.37

MgO 1.31 0.93 0.23 11.8 0.09 0.09 0.09 0.09 0.16

SiO2 1.76 1.06 97.9 8.75 7.03 6.49 6.62 6.62 3.24

Al2O3 0.35 0.48 0.75 1.71 3.12 3.03 3.09 3.09 1.80

TiO2 0.30 0.02 0.03 1.49 0.16 0.18 0.18 0.18 0.06

V2O5 0.21 0.01 0.004 4.57 0.00 0.19 0.00 0.00 0.00

Na2O 0.07 0.13 0.061 0.022 0.022 0.022 0.04

K2O 0.01 0.09 0.247 0.02 0.098 0.069 0.07 0.07 0.1

S 0 0.069 0.029 0.063 0.57 0.55 0.55 0.55 0.340

P 0.01 0.002 0.005 0.29 0.020 0.007 0.007 0.007 0.017

Mn 0.04 0.01 0.01 3.13 0.00 0.00 0.00 0.00 0.02

Fe 66.8 0.058 0.149 19.067 0.41 2.02 0.53 0.53 0.609

C 85.4 85.4 87.1 87.1 82.9

H2 0.087 0.087 0.089 0.089 4.10

O2 0.20 0.20 0.20 0.20 3.77

N2 1.16 1.16 1.188 1.19 2.18

Test Conditions

The test periods operated and evaluated consisted of four main parts

Reference period without nut coke in ferrous layers

Reference periods with 150 kg/tHM of original or Zr-traced nut coke charged in ferrous layers

Test period with 150 kg/tHM of Zr-traced, magnetite activated nut coke charged in ferrous layers

Test period with 150 kg/tHM of Zr-traced, lime activated nut coke charged in ferrous layers

From the operational tests, stable data periods stated in Table III were selected for the evaluation of in-furnace conditions, operational conditions as well as energy efficiency of the set-ups. The two periods for lime coated nut coke has the same start but the long period

extends longer in time including some slightly more varied conditions.

Table III Evaluation periods, 150 kg/tHM of nut coke was used in the ferrous layers in all test periods except for reference

Start End Recipe, type of nut coke Short name of period Duration

2013-05-02 21:00 2013-05-04 10:00 Reference without nut coke Ref. 37.0 h

2013-05-15 14:01 2013-05-15 23:54 Original nut coke Orig. 9.9 h

2013-05-15 23:56 2013-05-17 01:53 Zr-traced coke Zr-traced 26.0 h

2013-05-17 14:00 2013-05-19 12:30 Magnetite coated Zr-traced nut coke Magnetite 46.5 h

2013-05-20 14:00 2013-05-21 15:00 Lime coated Zr-traced nut coke Lime 25.0 h

2013-05-20 14:00 2013-05-22 03:30 Lime coated Zr-traced nut coke long Lime long 37.5 h

Recipe changes were made when starting to use a new type of nut coke, when the moisture content of coke changed, for heat level

control and in order to adjust the slag basicity for sufficient alkali removal. The amount of coke in the ferrous layers was 150 kg/tHM

when nut coke was added, except for during a ramping-up period in the beginning of the reference period with nut coke. As the

efficient C content varied between the nut coke types the amount of coke in the coke layers was influenced correspondingly.

During the all periods the pulverized coal injection (PCI) was kept fairly constant and changes in the amount of reducing agents were

adjusted by changing the coke rate. Also other basic operational parameters were successfully kept more or less constant during the

tests as can be seen in Table IV.

Table IV Indicative and actual operational parameters during trial periods for evaluation

Indicative Ref. Orig. Zr traced Magnetite Lime Lime long

Prod. Rate* 1.5 1.50 1.45 1.48 1.53 1.52 1.51 tonne/h

Tot. blast flow 1587 1584 1585 1580 1582 1582 Nm3/h

Blast air flow 1500 1500 1500 1500 1500 1500 1500 Nm3/h

O2 enrichment 110 111 110 110 110 110 110 Nm3/h

O2 in blast 50 50.6 50.3 50.4 50.1 50.2 50.2 Nm3/h

O2 to lances 60 60.5 59.3 59.3 59.7 59.4 59.3 Nm3/h

Tot. O2 in blast 26.4 26.6 26.6 26.6 26.8 26.7 26.7 Vol%

PCR 150 (225) 150 (226) 153 (221) 148 (219) 148 (226) 150 (228) 151 (228) kg/tHM (kg/h)

Moisture in blast 20 20 20 20 20 20 20 g/Nm3

Blast temp. 1200 1196 1196 1196 1196 1196 1196 C

Ave. blast temp. at tuyeres** 1120 1117 1114 1114 1114 1113 1113 C

Flame temp. ~ 2150 2187 2187 2190 2184 2180 2180 C

* from material balance, **average close to tuyeres

RESULTS AND DISCUSSION

C consumption in the BF during trials

The C consumption for each evaluation period was analyzed in heat and mass balance model based on the principles of RIST

diagram6. The calculations are using data converted to units on a per tonne hot metal (tHM) basis. In principle quite long stable

operational periods are required for getting reliable data for the heat and mass balance. On short-term e.g. the coke reserve can be

either built up or consumed and this will create errors if not taken into account.

Figure 7 Heat losses during each evaluation period Figure 8 Charged and by the process consumed C for each

evaluation period

Initially the collected Experimental BF data for each period was inserted in the model assuming that data as e.g. weights and analyses

for charged and tapped material and gas analyses are correct. The model iteratively calculates the blast volume and total heat losses.

The achieved values for blast volume are compared with the measured ones. Actual heat losses for the Experimental BF are based on

measured heat losses for water cooled part, estimated heat losses based on temperature measurements on the steel shell and calculated

heat losses related to the top gas. A large deviation between totally estimated heat losses based on data and the one calculated in the

model indicate changed amount of coke in the coke reserve. As can be seen in Figure 7, the un-known heat losses varies and e.g

during the period with Zr-traced nut coke the heat losses estimated in the model based on the charged C is much lower than those

stated based on the consumed C. During the first period with original nut coke the starting point was a higher fuel rate in order to

avoid disturbances caused by changed temperature and gas profiles. The coke reserve is accumulated and during the following period

it is then possible to reduce the fuel substantially without coming into low heat level.

-200

0

200

400

600

800

1000

1200

1400

Ref. Orig Zr Magnetite Lime Lime long

He

at lo

ss M

j/tH

M

Calc. tot heat losses charg. Calc. tot heat losses consump.Not known heat losses charg. Not known heat losses consump.

466

481

457459

453 453

463

474

471

458459 459

1410

1420

1430

1440

1450

1460

1470

450

455

460

465

470

475

480

485

Ref. Orig Zr Magnetite Lime Lime longTe

mp

era

ture

, C

C, k

g/t

HM

Charged C C consumed in process HM Temp

To overcome the impact on heat and mass balance from accumulation or consumption of raw materials the amount of consumed C

(coke and coal) is calculated based on the gas analyses and under the use of measured and calculated heat losses. In Figure 8 the

amount of charged and by the process consumed C, respectively, are stated. As can be seen, coke accumulation occurs during the first

period with nut coke when using original coke in the ferrous layers. During the next period when using Zr-traced nut coke the

consumption of some accumulated coke reserve is coke occurs.

The heat level is significantly higher during all test periods compared to during the reference period as shown in Figure 9. This results

in an increased consumption of C for periods when original or Zr-traced nut coke is used. For periods with activated nut coke the C

consumption is lower although higher heat level compared to during the reference. As can be seen the average hot metal temperature

during the reference is ~1429 C compared to 1446-1465 C during trial periods. Additionally, the Si content in hot metal differs as

well, se Figure 9. To be able to compare the C consumption for the different evaluation periods, model calculations for normalized

conditions were conducted. For normalized heat level a hot metal quality with 1.35 wt.-% Si and hot metal temperature of 1430 C

were selected, quite similar as for the reference period. In Figure 10 the difference in estimated C consumption for trial periods

relative reference period is shown for normalized conditions. It can be concluded that the C consumption is reduced with ~ 4-6

kg/tHM (Figure 10) if differences in heat level are not taken into account. For normalized data the reduction in C consumption is ~6-8

kg/tHM (Figure 11).

Figure 9 Average hot metal quality for each evaluation period Figure 10 Differences in by the process consumed C for each

relative the reference period for each trial period

During periods with higher heat level and higher Si content in hot metal the slag basicity is increased and the slag volume reduced.

This results in reduced alkali recovery to the slag. In Figure 12 the average K2O yield to the slag is shown. When the yield is low,

accumulation, recirculation and scaffolding may occur. Recirculation of alkali results in increased C consumption in the lower part of

the furnace due to the reduction and gasification of alkali compounds. In the upper part these are oxidized again. The thermal and

chemical energy returned in the upper part is evened out in the heat and mass balance but in the actual BF it will result in increased

energy consumption. Moreover, during this period the high Si content in hot metal requires an increasing amount to counteract the

accumulation of alkalis.

Figure 11 C consumption for normalized hot metal quality Figure 12 K2O yield and slag basicity

1429

1458

1465

1446

1456

1448

1.35

1.69 1.611.43 1.38 1.35

1

1.5

2

2.5

3

3.5

4

4.5

1410

1420

1430

1440

1450

1460

1470

Ref- Orig. Zr traced Magn. Lime Lime long

Wt-

% C

an

d S

i

Tem

pe

ratu

re,

C

HMT (C) C (%) Si (%)

0.0

11.2

8.2

-5.8

-4.3 -4.1

1410

1420

1430

1440

1450

1460

1470

-6

-4

-2

0

2

4

6

8

10

12


Tem

pe

ratu

re,

C

Dif

fere

nce

in C

co

msu

mp

tio

n, k

g/tH

M

Change in C consumption relative ref. HM Temp

0.0

4.9

2.1

-7.8

-6.4-5.7

-10

-8

-6

-4

-2

0

2

4

6

8

10

430

435

440

445

450

455

460

465

470

475

480


Dif

f. in

C c

on

sum

p. r

ela

tive

ref

., k

g/tH

M

Esti

mat

ed

C c

on

sum

pti

on

, kg/

yHM

C consumed in process Normalised C cons. in process Diff. Normalised cons.

0.80

0.85

0.90

0.95

1.00

1.05

1.10

0%

20%

40%

60%

80%

100%

120%

140%

160%

Ref Orig Zr traced Magn. Lime Lime long

Slag

bas

icit

y, B

2

K2O

yie

ld, %

K2O yield Slag basicity, B2

Impact on gas efficiency

The gas efficiency was calculated from top gas analyses and from in furnace gas analyses measured during shaft probing. The gas

efficiency calculated from top gas analyzes increases with approximately 1.5 % when activated nut coke is used as can be seen in

Figure 13. Periods during which original and Zr-traced coke is charged in the ferrous layers are operated under quite high heat level

and high coke rate. In spite of this, the gas efficiency is in the same range as for the reference period that has significantly lower heat

level. This indicates that the addition of nut coke in general is beneficial for the gas distribution. It could also be noted that although

that the hot metal indicated high heat level the top gas temperatures and amount of water dosage in the BF top could be kept at desired

levels, Figure 14.

Figure 13 Average burden descent, top gas efficiency, vol.-% of

H2 per evaluation period calculated from top gas analyses

Figure 14 Average top gas temperature and water dosage at

top per evaluation period

At the upper probe level the gas efficiency is higher during periods with activated coke, see Figure 15. At the lower probe level the gas

efficiency is as seen in Figure 16 highest for periods with magnetite-activated nut coke. In between the tuyeres the gas efficiency is

high also for lime-activated coke. Above the raceway the gas efficiency is quite similar for all periods except for during the magnetite-

activated ones.

Figure 15 Gas efficiency per evaluation period calculated from

gas analyses during probing at upper probe level

Figure 16 Gas efficiency per evaluation period calculated from

gas analyses during probing at lower probe level

Impact on thermal reserve zone temperature

The temperatures measured within the shaft are influenced both by the chemical reactions and the heat transfer from ascending gas.

When the general heat level in the furnace is increased the temperature isotherms is moved upward in the BF. It is difficult to compare

the temperature at one vertical position in the shaft for periods with different heat level without knowing that this position is within the

thermal reserve zone. As indicated by the vertical temperature profiles Figure 19 the thermal reserve zone starts for several of the

measurements approximately at the position of upper shaft probe (0.90 m below stockline) and ends before or at the position of the

lower probe level (3.46 m below stockline). Therefore the temperatures at upper and lower probe, as shown in Figure 17 and Figure

18, cannot in general be used for estimations on the thermal balance controlling the thermal reserve zone temperature. These

temperatures seem to be influenced by the thermal level of the process. Additionally, the probes for temperature measurements are

47.747.5

47.7

49.2 49.2

49.0

46.5

47.0

47.5

48.0

48.5

49.0

49.5

0

1

2

3

4

5

Ref. Orig. Zr traced Magnetite Lime Lime longG

asef

fici

en

cy, %

Bu

rde

n d

esc

en

t, c

m/m

in, v

ol%

H2

Burden descent vol%H2 Gas efficiency, %

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

160

165

170

175

180

185

190

Ref. Orig. Zr traced Magnetite Lime Lime long

Wat

er

do

sage

, lit

res/

min

Top

gas

te

mp

era

ture

, C

Top T Water dosage

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9

Gas

eff

icie

ncy

, %

Position

Ref. Orig. Zr traced Magn. 1 Magn. 2 Lime and lime long

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9

Gas

eff

icie

ncy

, %

Position


water cooled. However, it is indicated that the use of 150 kg/tHM of nut coke results in a flatter temperature profile with less extensive

central gas flow. In the vertical temperature measurement a lowered thermal reserve zone temperature is measured for the period with

lime-activated coke as seen in Figure 19. The period with magnetite-activated nut coke shows similar temperature profile as for non-

activated nut coke.

Figure 17 Horizontal temperature profile measured during stated

evaluation period at upper probe level

Figure 18 Horizontal temperature profile measured during

stated evaluation periods at lower probe level

Based on the horizontal and vertical measurements conducted during the evaluation periods but also in connection to them a measured

temperature was deduced and used in the heat and mass balance calculations. If the measured temperature is used in the heat and mass

balance calculations the shaft efficiency reached more than 100% for Zr-traced and magnetite-activated periods. Assuming a similar

shaft efficiency of 99% for all periods, a lower temperature is estimated for all evaluation periods when using activated nut coke, Figure 20.

Figure 19 Vertical temperature profiles measured within

evaluation periods

Figure 20 Measured and calculated thermal reserve zone

temperature

450

500

550

600

650

700

750

800

1 2 3 4 5 6 7 8 9

Tem

pe

ratu

re

c

Position


450

550

650

750

850

950

1050

1 2 3 4 5 6 7 8 9

Tem

pe

ratu

re

c

Position

Orig. Zr traced Magn. 1 Magn. 2 Lime and lime long

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 200 400 600 800 1000 1200

Dis

tan

ce f

rom

sto

cklin

e, m

m

Temperature C

Ref. Zr tracedMagn. 1 Magn. 2Lime and lime long

1000 1000

1060 1060

960 960

1023

9941002

965 961

974

900

920

940

960

980

1000

1020

1040

1060

1080


Tem

pe

ratu

re,

C

Approximate measured Calculated for 99% shaft efficiency

CONCLUDING REMARKS

During the Experimental BF trials stable operation could be achieved when using 150 kg/tHM of nut coke in the ferrous layers. The

gas efficiency was in general high for all periods and increased from the reference the to the activated nut coke periods.

The charging of high amounts of nut coke is believed to improve the horizontal gas distribution.

High gas efficiency could be achieved although high coke rate during periods with original and Zr-traced nut coke

The horizontal gas profile at upper shaft probe level became flatter with less significant central gas flow

The top gas temperature and water dosage was not significantly increased when high heat levels were reached

Further increase in gas efficiency during periods with activated nut coke is likely caused by lower thermal reserve zone temperature

that improves the indirect reduction of ferrous material and decreases the direct reduction. Lower thermal reserve zone temperatures

were indicated by measured data and heat and mass balance calculation results. Lowering of the thermal reserve zone temperature

moves the equilibrium for Femet/FeO to CO/CO2 towards Femet during the periods with activated nut coke.

The C consumption calculated for all periods using normalized hot metal heat level in terms of Si content and tap temperature states a

reduction of C consumption with 6-8 kg/tHM when activated nut coke is charged. The highest savings are achieved during the period

with magnetite-activated nut coke.

For industrial implementation the method for activation has to be further developed. In the method used the coke reaches a moisture

content corresponding to saturation and cannot be charged without previous drying.

ACKNOWLEDGEMENTS

The research work presented in this paper has been carried out within the project of Innocarb, RFSR-CT-2010-00001, that is co-

funded by the Research Fund for Coal and Steel (RFCS). Swedish Energy Agency is greatly acknowledged for additional financial

contribution. The paper is a contribution from CAMM, Centre of Advanced Mining and Metallurgy, at Lule University of

Technology that supported the research scientifically and economically.

REFERENCES

1. A. K. Biswas, Principles of Blast Furnace ironmaking, Theory and Practice, Cootha Publishing House, Brisbane, Australia(1981), pp 122-132, p 74

2. S. Nomura, H. Ayukawa, H. Kitaguchi, T. Tahara, S. Matsumaki, M. Naito, S. Koizumi, Y. Ogata, T. Nakayama, T. Abe, Improvement in Blast Furnace Reaction Efficiency through the Use of Highly Reactive Calcium Rich Coke, ISIJ Int. Vol 45

(2005), No. 3 pp 316-324

3. S. Nomura, H. Kitaguchi, K. Yamaguchi, M. Naito, The characteristics of Catalyst-coated Highly Reactive Coke, ISIJ Int. Vol. 47 (2007), No. 2 pp 245-253

4. S Nomura, H Terashima, E Sato, M Naito, Some Fundamental Aspects of Highly Reactive Iron Coke Production, ISIJ Int. Vol. 47 (2007), No. 6 pp 823-830

5. S. Watakabe, K. Takeda, H. Nishimura, S. Goto, N. Nishimura, T. Uchida, M. Kiguchi, Development of High Coke Mixed Charging Techniqiue to the Blast Furnace, ISIJ Int. Vol. 46 (2006), No. 4 pp 513-522

6. Patrick Lawrence Hooey, Axel Bodn, Chuan Wamg, Carl-Erik Grip and Bjrn Jansson, Design and Application of a Spreadsheet-based Model of the Blast Furnace Factory, ISIJ International, Vol. 50 (2010), No. 7, pp. 924930

impact of activated nut coke on energy efficiency in the blast furnace

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