Page 24 - Steel Tech India eMagazine Volume April 2022

VOL. 16 • NO. 3 • April 2022

plant pollutants and disturb its bio-diversities. living Sinter Plant: the concept of sinter plant was introduced
creatures of rivers or oceans are disturbed and their for the utilization of ore fines. During excavation and
normal life style is hampered. Iron and steel plant drains mineral processing lots of ore fines are generated.
out oil, process water with organic matter, benzene, In sinter plant these ore fines along with flux and
phenol, acids, suspended solids, sulfides, sulfates, reducer i.e., coke breeze with addition of adequate
ammonia, cyanides, fluorides etc. Solid waste of a binders isthermally agglomeratedat 1300–1480 c [12,13] .
o
steel plant is dumped in dump yard nearer to the plant Figure 2 represent the flow diagram of a basic sinter
premises. Due to unwanted dumping of solid waste lots plant [14] . In sinter plant ore fines, process waste like
of land are occupied. Soil of the particular area gets SMS sludge, mill scale etc. of particle size less than
contaminated and the natural behavior of the soil gets 10 mm along with coke breeze and flux like lime,
altered. Some of the solid waste has high chemical limestone and dolomite are mixed with binders and
potential causing etching to the human body when then agglomerated & thermally heated in order to
comes in contact. Maximum solid waste in the dump increase the strength of the sintered material prior to
yard is found in form of fine particles. the fine particle charge it in blast furnace . During the operation lots
[15]
flows along with running wind causing heavy dust and of dust generates. Fine particles are accumulated
contaminates human body specially lungs. Some of the through sinter plant air cleaning system, dust catcher
common solid wastes in steel plant are sludge, slag, and gas cleaning system. these fine particles are
scrap, scales etc. considered as sinter plant waste. this dust particle is a
mixture of ore fines, carbon and flux containing distinct
Integrated Steel Plant
amount of iron, SiO , caO, MgO and other minerals
2
An integrated steel plant is having all the functions along with small quantity of carbon. The particle size
(starting from raw material beneficiation to finished of these dusts is very small, can easily mixed and
steel) for primary steel production under one premise. blown away by natural air circulation or storm causing
An ideal steel plant is having ore beneficiation unit, nose and lungs inflammation which is considered as
screening units, coke oven plant, burden handling health hazard. Proper technology advancement may
system, sinter plant/ pelletizing unit, blast furnace, basic open a new route to utilize those waste generated from
oxygen furnace, continuous caster, re-heating furnace, sinter plant resulting in minimization of dumped waste.
rolling mills, power plant, calcination plant etc. Figure 1 Iron may be extracted from these dust particles by
shows the brief flow sheet of an integrated steel plant. developing suitable techniques in future. Studies may
Principal raw materials used in an integrated steel be done to find new techniques for the agglomeration
plant are iron ore, lime stone (flux) and coal / coke of these dusts as the particle size is extremely small.
(reductant).During the total process lots of waste are Some of the plants have been using these dusts and
generated which are summarized with possible and agglomerate it as a micro pellet and reuse in sinter
practiced remedies. plant. Some sinter plants are making briquettes and

Waste Generated by an Integrated Steel Plant along using it in blast furnaces and basic oxygen furnaces.
with its Remedies Steel Melting Shop: Molten pig iron from blast furnace is

Integrated steel plant possesses several process transferred to basic oxygen furnace or lD convertor
units and these process units generate huge quantity using a ladle for oxidation process in order to remove
of waste. Starting from mineral processing unit and extra carbon, phosphorous, sulfur and other elements
ending with rolling mills each operation generates to match the desired property of steel. Slag generated
waste in all three forms which are environmentally during the process is called steel slag which is a process
hazardous. The waste generated from each process of waste. Other distinguished waste in steel melting shop
an integrated steel plant has mineral values.Utilization is steel melting sludge.
of those wastes can be beneficial. Proper techniques the generation of lD slag during the production of
shall be incurred to extract the metals from the waste steel is around 150 – 180 Kg per ton of crude steel
of an integrated steel plant. In this particular segment production . lD slag is generally not used like BF
[16]
the waste related to sinter plant, steel melting shop is slag due to high phosphorous content. lD slag has
discussed. properties like high hardness, cementitious in nature,

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