Steel will
probably remain the world’s one of the most important engineering materials for
a long time to come. With strong backward and forward linkages, steel industry
is an engine of economic growth and a symbol of economic prosperity. Moreover,
steel is vital to the nation’s economic security as it is extensively used in
strategic areas such as defence, power, atomic energy, and in creation of
social and economic infrastructure of the country. Given the importance of
steel, the Iron and Steel industry in India has also grown exponentially during
the last decade. On the basis of growth witnessed, India has set itself a
target of achieving production capacity of 300 MT of Steel by 2025 and the
required quantity of Iron ore is projected at 480 MT.
Over the next
few years, demand for Indian Iron ore is expected to rise by more than 500
million tons per year to meet the internal demand and export. As per United
Nations Framework Classification (UNFC) of mineral resources, total resources
of iron ore in the country is around 28.52 BT (National Mineral Inventory) as
on 1st April 2010. Out of this total, 18.88 BT is haematite
consisting of 8.09 BT under reserve category and remaining 9.79 under resource
category. Remaining 10.64 BT is magnetite consisting of merely 0.02 BT under
reserve category and remaining 10.62 BT under resource category. Hence, it is
evident that India has vast deposits of superior quality hematite ore, categorised
as direct shipping ore, which just needs crushing and sizing to be used as metallurgical
feed. However, such deposits are depleting at faster rate. For the projected
steel production, existing reserves of hematite will not last beyond 15 – 20
years. Hence additional domestic resources have to be used on priority basis.
The country has
huge amount of low-grade iron ore but exploration and mining efforts to utilise
low-grade iron ores have not been sufficient. This includes banded iron
formations like Banded Hematite Quartzite (BHQ), Banded Hematite Jasper (BHJ)
etc. Such ores invariably have low iron content, less than the cut-off grade of
45 percent. Given the current stage of economic development, it is not only
required to explore new deposits but also to make use of low-grade ores, such
as these.
Extensive
R&D work is being carried out at various laboratories in India such as National
Mineral Development Corporation Research and Development Centre, Hyderabad and
Ore Dressing Laboratory at Indian Bureau of Mines on the utilisation of
low-grade iron ore for steel production. The flow sheets developed on almost
all types of ores reflect the possibility of producing concentrate suitable for
sinter and pellet making.
With regard to BHQ
- a low-grade iron ore with iron content ranging between 37 percent and 44
percent as well as liberation size of 100–150 microns - direct grinding of BHQ
to -150μ size and then treating with Wet High Intensity Magnetic Separators (WHIMS)
can improve the quality of the product to iron content ranging between 55 to 57
percent. This final concentrate coupled with suitable agglomeration technique
can be used in blast furnace for steel production. NMDC plans to set up the
first BHQ beneficiation plant with a capacity of three hundred thousand tonnes
a year at an estimated cost of INR 150 crores, which will demonstrate the
commercial viability of the technology for BHQ beneficiation.
In the light of
prevailing Indian scenario it may be concluded that value addition of low grade
iron ore is crucial. The process of beneficiation followed by agglomeration
will not only conserve the limited high grade lumpy iron ore but will also
stimulate optimum utilisation of low grade ores.
Infraline Energy Metals & Mining Research Team
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