Direct-reduced iron (DRI) also called sponge iron, is produced
from direct reduction of iron ore (haematite) in the solid state by a
reducing gas produced from coal. India ranks first and produced
more than 27% of the world’s DRI(23.4 million tons, Mt). In the year
2013, Worldwide DRI production was 75 Mt, which was more than
85% greater that produced in 2001 (Midrex, 2014). The principal
raw materials required for sponge iron production are iron ore,
non-coking coal, and dolomite. For an example, production of
100 ton sponge iron requires 154 t (65 wt% Fe) iron ore and 120 t (B
grade) coal and generates 45 t solid waste out of which 25 t is char
(dolochar). In the absence of good grade coal, sponge iron
industries are using poor quality coal (F grade) with contains
more than 40% by weight of ash leading to more waste generation.
Slag is also generated from the sponge iron plant or SMS (steel
melting shop) plant in the process. Therefore, in an integrated
sponge iron plant, large quantities of solid wastes generated in the
form of dolochar, slag and fly ash, which are dumped together due
to scarcity of space to cover a large area exceeding of 40–50 m. They
caused severe air pollution problems during the summer, while in
monsoon, the loose waste were easily carried away along with runoff
to pollute the nearby water bodies. The waste is very
homogenous, loose and devoid of nutrients, hence stabilization
of this type of waste poses a severe challenge.
In the present study, a challenging task was undertaken to
ecologically restore a huge waste dump covering 7 ha ground area
(top flat surface area of 5 ha), aerial height of 50–70 m, without any
intermediate benching with steep slope (>70). Practically no space
was available to reduce the slope. The sequence of restoration
operation was (i) regrading of the dump, (ii) blanketing with
topsoil, (iii) covering the slope with coir-mat, (iv) sowing of grass–
legume mixture on the slope, (v) construction of drainage, (vi)
Direct-reduced iron (DRI) also called sponge iron, is producedfrom direct reduction of iron ore (haematite) in the solid state by areducing gas produced from coal. India ranks first and producedmore than 27% of the world’s DRI(23.4 million tons, Mt). In the year2013, Worldwide DRI production was 75 Mt, which was more than85% greater that produced in 2001 (Midrex, 2014). The principalraw materials required for sponge iron production are iron ore,non-coking coal, and dolomite. For an example, production of100 ton sponge iron requires 154 t (65 wt% Fe) iron ore and 120 t (Bgrade) coal and generates 45 t solid waste out of which 25 t is char(dolochar). In the absence of good grade coal, sponge ironindustries are using poor quality coal (F grade) with containsmore than 40% by weight of ash leading to more waste generation.Slag is also generated from the sponge iron plant or SMS (steelmelting shop) plant in the process. Therefore, in an integratedsponge iron plant, large quantities of solid wastes generated in theform of dolochar, slag and fly ash, which are dumped together dueto scarcity of space to cover a large area exceeding of 40–50 m. Theycaused severe air pollution problems during the summer, while inmonsoon, the loose waste were easily carried away along with runoffto pollute the nearby water bodies. The waste is veryhomogenous, loose and devoid of nutrients, hence stabilizationof this type of waste poses a severe challenge.In the present study, a challenging task was undertaken toecologically restore a huge waste dump covering 7 ha ground area(top flat surface area of 5 ha), aerial height of 50–70 m, without anyintermediate benching with steep slope (>70). Practically no spacewas available to reduce the slope. The sequence of restorationoperation was (i) regrading of the dump, (ii) blanketing withtopsoil, (iii) covering the slope with coir-mat, (iv) sowing of grass–legume mixture on the slope, (v) construction of drainage, (vi)
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