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UTILIZATION OF STEEL PLANT WASTES BY AGGLOMERATION: A Review --- Ela
Jha and S. K. Dutta
Conference Paper · January 2013
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2. Proc. of the 1
st
International Conference on Emerging Trends in Mechanical Engineering, January 4
th
-5
th
, 2013
G. H. Patel College of Engineering & Technology, V. V. Nagar- 388120, Gujarat, India
ISBN: 978-1-61233-6244
246
MSE07
UTILIZATION OF STEEL PLANT WASTES BY AGGLOMERATION:
A Review
Ela Jha1
and S. K. Dutta2
1
G. H. Patel College of Engg. & Technology, Mechanical Engineering Department
Email:Ejha08@gmail.com
2
Metallurgical and Materials Engg. Dept., Faculty of Tech. & Engg., M. S. University of Baroda
Email:drskdutta1981@gmail.com
Abstract
In a steel industry a number of manufacturing processes are employed involving
use of various raw materials and during the process, many valueless substances
are generated which can be termed as waste materials. Recently the aspect of
waste management has caught the attention of technocrats and others. The
intrinsic ability of steel to be completely recycled offers good prospects for
sustainable development of the steel industry. The industrial development
programme of any country, by and large, is based on its natural resources. India
is fortunate to have reserves of high grade iron ores. However, with the
increasing mining activity and exports of high grade ores; high grade reserves
are slowly and steadily getting depleted. Indian iron ore deposits are also soft
and friable in nature, hence large amount of fines are generated. Solid wastes of
steel plants are produced from process units and pollution control equipments.
This paper highlights the possible ways of processing some of these waste
materials for their optimum utilization by agglomeration.
1. Introduction
Steel is the driving force of economic progress. The steel industry in India is poised to take a
huge leap in production of the steel from 72.2 million tonnes (Mt) in 2011 to about 200 Mt by
2020. At such a juncture, mindless production boom sans any concern for the environment can
ruffle the steel scenario. The industrial development programmed of any country, by and large,
is based on its natural resources. Production of 72 Mtpa finished steel would require about 123
Mtpa of iron ore. Table 1 shows the status of iron ore reserve in India, ranking sixth in the world,
according to estimate by Indian Bureau of Mines, Nagpur as on 1st
April 2000 [1]. However, with
the increasing mining activity and exports of high grade ores; high grade reserves are slowly
and steadily getting depleted. Indian iron ore deposits are also soft and friable in nature, hence
large amount of fines are generated.
However, in a steel industry where a number of manufacturing processes are employed
involving use of various raw materials and during process, many seemingly valueless
substances are generated which are known as waste materials (Figure 1). Now a day, the
aspect of waste management at various levels from mines to smelters has caught the attention

3. Proc. of the 1
st
International Conference on Emerging Trends in Mechanical Engineering, January 4
th
-5
th
, 2013
G. H. Patel College of Engineering & Technology, V. V. Nagar- 388120, Gujarat, India
ISBN: 978-1-61233-6244
247
of technocrats, mineral economists, planners and the consumers. Today the management of
mineral commodities has valuable waste of various natures at its disposal, which assume
paramount importance and need to be dealt with in a judicious and sustainable manner. With
the scenario changing, on passage of time and with the technologies getting regularly upgraded,
there is need for use of such waste materials continuously being produced in large quantum
through conversion of work materials to either by-products or in-process material for recycling.
For easy understanding, the steel plant solid wastes have been broadly classified into two
categories:
I) Solid waste generated from process units,
II) Solid waste generated from pollution control equipment.
Steel Plant Waste
Solid
Liquid Gas
Raw Material
Fines
Slag Flue Dust Sludge
Ore Coal Coke Lime
MILL SCALE
Figure 1: Steel Plant Wastes
One of the major concerns of world steel plants are the disposal of wastes generated at various
stages of processing. The global emphasis on stringent legislation for environmental protection
has changed the scenario of waste dumping into waste management. Because of natural drive
to be cost effective, there is a growing trend of adopting such waste management measures as
would convert wastes into wealth, thereby treating wastes as by-products.
Recycling Techniques [2]:
• Return waste material to original process.
• Use the waste material as a raw material substitute for another process.
• Process waste material for resource recovery.
• Process waste material as a by-product.
• Investigate contractors to recycle waste material.
Indian coal reserve is shown in Table 2 [3]. There is shortage of coking coal all over the world in
general and in particular in India. Again a lot of coal fines and coke breeze are also produced
during coal mining and coking of coal respectively. Utilization of these fines for extracting metal
is of vital concern for resource conservation and pollution control. The option is to convert the
iron ore and coal / coke fines into composite pellets / briquettes. By producing cold bonded iron
ore-coal / coke composite pellets / briquettes from iron ore and coal / coke fines, utilization of

4. Proc. of the 1
st
International Conference on Emerging Trends in Mechanical Engineering, January 4
th
-5
th
, 2013
G. H. Patel College of Engineering & Technology, V. V. Nagar- 388120, Gujarat, India
ISBN: 978-1-61233-6244
248
these fines takes place and also controls the pollution. India now represents one of the fastest
growing economics in the world and the rapid growth of steel consumption and production (4th
position in the world, 72.2 Mt during the 2011) is an important contribution factor. Taking into
consideration the optimum use of the raw materials use in steelmaking, so that valuable non-
renewable materials are conserved and last longer by re-cycling of wastes as well as
conversion of wastes into value added products.
Table 1 Iron Ore Reserves in India (Mt)
Grade
A.
Lump
s
(%)
B.
Fines
(%)
C.
Lump
s &
Fines
(%)
D.
Prospect
ive
Resourc
es
(%)
E.
Other
s
(%)
Total
Hematite
[A+B+C+D
+E] (%)
Magnet
ite
(%)
Total
Resourc
es
Mt (%)
High
915.28 139.22 409.1
------ ------
(7.09%
)
(1.08%
)
(3.17
%)
Medium
2822.9 2506.9
421.2
2
------ ------
(21.87
%)
(19.42
%)
(3.26
%)
Low
1131.9 1325.5
331.7
5
------ ------
(8.77%
)
(10.27
%)
(2.57
%)
Unspecifi
ed
533.23 354.19
116.6
5
------ ------
(4.13%
)
(2.74%
)
(0.9%
)
Sub-
total
5403.3 4325.8
1278.
72
1480 417.9 12905.79
10682.2
1
23588
(41.87
%)
(33.52
%)
(9.9%
)
(11.47%)
(3.24
%)
(100%)
(54.71%)
(45.29
%)
(100%)
Table 2. Indian Coal Reserve (as on 1. 4. 2010) (Bt)
Type of
Coal
Proved
Reserve
Indicated
Reserve
Inferred
Reserve
Total
Reserve

5. Proc. of the 1
st
International Conference on Emerging Trends in Mechanical Engineering, January 4
th
-5
th
, 2013
G. H. Patel College of Engineering & Technology, V. V. Nagar- 388120, Gujarat, India
ISBN: 978-1-61233-6244
249
Coking
17.669
(16.1%)
13.642 2.102 33.413
Non-
coking
92.129
(83.9%)
117.012 34.257 243.398
Total
109.798
(39.7%)
130.654 36.359
276.811
(100%)
Table 3 Various Wastes Produced at Iron & Steel Plants
Unit
Solid Wastes from Process
Units
Solid Wastes from
Pollution Control Units
Coke Oven & By-
product Plant
• Coke Breeze
• Tar Sludge
• Acid Sludge
• Coke Fines
Sinter Plant • Under Size Sinter • Dust
Blast Furnace • Slag • BF Flue Dust
Steel Making Shop
• Slag
• Broken Refractory
• SMS Dust
Rolling Mills
• End Cutting
• Broken Refractory
• Mill Scale
• Oily Sludge
Raw Material Handling
Plant & Refractory
Plant
• Fines • Dust
Average about 400 kg of solid wastes generate per tonne of crude steel production. World’s
crude steel production was 1.527 Bt in 2011, along with it, generated huge amount of wastes. In
2011 India’s crude steel production was 72.2 Mt (60% increase of production in last 5 years)
with waste generate about 23 Mt (64% increase in last 5 years) [4].
The present study has two objectives: (i) to recover the iron and metallic values by flotation and
magnetic separation techniques, (ii) recycle the whole material to form briquette / pellet making.
2. Review of Earlier Works

6. Proc. of the 1
st
International Conference on Emerging Trends in Mechanical Engineering, January 4
th
-5
th
, 2013
G. H. Patel College of Engineering & Technology, V. V. Nagar- 388120, Gujarat, India
ISBN: 978-1-61233-6244
250
Integrated steel plants in general, produce large amounts of solid wastes during iron and steel
making process. These solid wastes have many valuable products, which can be reused if
recovered economically. A large number of literature [4-8] are available on total management of
waste generated from a Steel plant focusing on different aspects of pollution measures, safe
disposal and recirculation etc. As regards the metallurgical slag, reports are available on
utilization of BF Slag while slag from steel melting shop is not fully discussed because of
inherent problems like LD process is suitable for recycling steel waste to produce a high-tech
steel product and it is ecologically superior over some other steel melting processes. Kim et al
[8] has studied the physico-chemical characteristics of LD slag. The major phases that are being
found in LD slag includes dicalcium ferrite, calcium aluminate and wustite. Steel slag also
contain some reactive mineral phases such as 2CaO.SiO2, 3CaO.SiO2 and free CaO and MgO
Efforts are being made to utilize the waste materials by proper characterization, beneficiation
and agglomeration techniques [9-11]. As the treatment of blast furnace sludge/dusts is still an
unsolved problem in many countries of the world [12, 13].
Mayson and Mukerji [14] studies that due to increase in demand for steel through out the world
that caused a corresponding increase in steel demand in India. To cope up with the demand
players in both the private and public sectors are planning to increase steel production both
through brown field and green field expansion. The steady depletion of high grade, lump
yielding ore reserves, accumulation of large quantities of sub grade fines and tailings are
compounding the problem further. The need of the hour is to meet the challenge head on and
devise technology to beneficiate and agglomerate the tailings and sub grade fines. 12 million
tonnes low grade fines (-8 mm) have accumulated at Jharandalli, Mahamaya and Dalli Mines
which have been termed as “Generated Fines”. These low grade fines are having about 57-58%
Fe content and contain 12-14% +10 mm fraction. They suggested that benefits as followings:
• Gain-full utilization of low grade fines for iron making after beneficiation. The yield of
beneficiated fines shall be about 60 – 65 % having +63 % Fe.
• Reductions in the dumping load at mines to an appreciable extent and reduce the influx of
fine grained washouts which cause land degradation.
• The slime generated from beneficiation process can be further utilized as input to the
beneficiation pellet plant being installed at mines.
• In future all the regular generation of low grade fines shall be directly diverted to the
proposed unit instead of dumping.
It has been suggested that effective utilisation of iron bearing dusts and sludge can be done by
agglomeration process. The pellet produced in this process can be directly fed as sinter feed or
directly in Blast Furnaces.
The generation quantity of various types of waste materials differ from one steel plant to another
depending upon the steel making processes adopted and pollution control equipment installed.
The huge quantities of iron ore slimes (containing 55 to 60% iron, size < 0.15 mm) collected in
tailing ponds, estimated to be 130 Mt (accumulate to the tune of around 10 Mt per year in India)
are not being utilized at present . Apart from that, mill scales are the industrial byproduct, which
are produced due to hot working processes. Mill scales are produced in large amount by various
processes like hot rolling, forging, heat treatment of steels etc. Most of these mill scales, which
are combined with lubricant or oil, are treated as waste materials. At present, most of the slimes
and mill scales are thrown away as waste for land filling and create pollution to the environment,

7. Proc. of the 1
st
International Conference on Emerging Trends in Mechanical Engineering, January 4
th
-5
th
, 2013
G. H. Patel College of Engineering & Technology, V. V. Nagar- 388120, Gujarat, India
ISBN: 978-1-61233-6244
251
which are not desirable. All the wastes coming from various units of Steel plants will have
different chemistry. Hence beneficiation technique needed to be reviewed.
3. Approach for Beneficiation done by research works [15] as follows:
I) Two-step approach to optimize the beneficiation process:
Step 1: Gravity Separation at coarser particle size
• Diester concentrate table
• Spiral
Step 2: Gravity separation product was subjected to:
• Magnetic separation
• Reverse flotation
II) Novel Roasting method followed by magnetic separation
They concluded that the yield of the conventional and the novel approach is made and the
results were found to be as:
• Conventional Flotation process resulted in 18.2 % recovery and 62.6 % Fe
• Novel Roasting method yielded 26.1 % recovery and 60.05 % Fe
The beneficiated wastes can be used by agglomeration i.e. by making pellets.
4. Utilization of Wastes Pelletization
The agglomeration is a process which uses fine particles, added with binders or other products
to form pellets, briquettes or nodules (sinter). This process is mainly used to produce iron ore
pellets which supply the blast furnaces. The performance of a pelletizing circuit requires
physical processes such as regrinding, hydroclassification, screening, mixing and usage of
balling discs or drums to form the pellets. The quality of the end product is also influenced by
the addition of specific additives and their methods of addition.
• Fine iron ore concentrate is pelletized into spherical balls of 8-20 mm diameter and then
indurated up to 13000
C in an induration furnace to enhance the mechanical strength of
pellets.
• In the induration process, fuel (liquid or gaseous) is consumed to supply the heat, thus
CO2 and other pollutants are emitted.
By Cold bonding method, induration of pellets are not required, the mechanical strength of
pellets can be achieved at low or room temperature; there is no pollution
5. Conclusion
1. India is poised for a leadership role in steel production; that takes into account optimum use
of raw materials would be important.

8. Proc. of the 1
st
International Conference on Emerging Trends in Mechanical Engineering, January 4
th
-5
th
, 2013
G. H. Patel College of Engineering & Technology, V. V. Nagar- 388120, Gujarat, India
ISBN: 978-1-61233-6244
252
2. Utilization of iron ore fines for extracting metal is of vital concern for resource conservation
and pollution control.
3. By producing cold bonded iron ore-coal / coke composite pellets / briquettes from iron ore
and coal / coke fines, utilization of these fines takes place for resource conservation and also
controls the pollution.
4. Various routs are available for beneficiation of wastes, out of which on is to be selected as
per the chemistry and fineness of the wastes.
5. Utilization of iron ore and coal fines by producing composite pellets, which are the value
added products and turn the waste into wealth.
References
1. R. K. Sharma: Iron Ore Availability vis-à-vis Steel Industry, JPC Bulletin on Iron and Steel,
Vol. 5, No. 11, Nov 2005, pp. 7-18.
2. Dhawan V.K., An Overview On Waste Management In Steel Industry, Proce International
Seminar on Waste Management in Iron & Steel Industry, May, 2008, Rourkela. pp.
3. The Indian Coal Scenario: Performance Review Iron & Steel 2009-10, pp 33-40.
4. S. K. Dutta and R. Sah: Utilization of Iron Ore and Coal Fines–An Approach for Resource
Conservation and Pollution Control, Proc of 1st International Quality Congress & 6th Indian
Congress on Quality, Environment, Energy and Safety Management System, (6th ICQESMS),
Management System for Sustainability, (Ed S K Ghosh), Oxford Publishing House, Kolkata;
BPC, Vadodara, December 2010, pp 361-66.
5. Annual Report 2010-11, Ministry of Steel, Govn of India
6. Chatterjee, A., Murthy Ch. V. G. K. Sripriya, R., and Prasad, H. N. (1993) Challenges of
Recycling steel plant dusts/ sludge. Powder handling and processing, v.5(1), pp. 53-57.
7. Basu, G. S., Sarkar, P. K., Sharma, R. P., Ahemad, A. and Dhillon, A. S. (1997) Recycling &
reuse of solid waste at Tata Steel, Tata Search, pp.118-120.
8. Kims Chul-Ho and Jung. S. M. (1998) SEAISI) Quarterly, pp. 29-34.
9. Ghosh, B. and Sinha, S. N. (1990). Procd. Sem. on Waste Management, pp. 170-182.
10. Braeza, N. A. and Nelson, L. R. (1991) Technology for the treatment of steel plant dusts,
World Steel Review, 1 (1), Mintek, pp. 27-35.
11. Kreulitsch, H. and Krieger, W. (1991) The LD process - an ecological optimized process, pp.
271-278.
12. Roy, T.K., Sinha, B.B., Singh, Balwanta, and Das, A.K., The Metallurgy of solid waste
recycling in integrated steel plants. Tata Search, 1998, 123-126.
13. Uno, S., Umelsu, Y., Ohmizu, M., and Munakakata, M., Deziding Equipment and Operation
based on Wet Classification of wet cleaned Blast furnace Dust. Nipon Steel Technology Report,
1979, 13, 80.
14. Mayson, N.K and A. Mukerji, Use of sub-grade ore a case study, Proce International
Seminar on Waste Management in Iron & Steel Industry, May, 2008, Rourkela. pp.
15. Project Review April 2012, JSW R&D
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