1939
Enhancing Flotation Kinetics and Magnetic Separation
Efficiency for Iron and Carbon Recovery from Blast Furnace
Flue Dust through Particle Liberation
Deepak Kumar Sahu
CSIR-Institute of Minerals and Materials Technology, Bhubaneswar
G.G. Roy
Indian Institute of Technology, Kharagpur
S.K. Biswal
International PranaGraf Mintech Research Centre, Bhubaneswar
ABSTRACT: The present study investigates the impact of particle liberation on flotation kinetics and magnetic
separation processes, aiming to enhance the recovery and separation of ferruginous and carbonaceous materials
from the blast furnace flue dust. Effect of particle liberation with varying feed size viz. 200, 325 and 500 mesh sizes
were evaluated. Optimisation studies were carried out through cell floatation and magnetic separation (LIMS
&WHIMS). A feed sample with Fe(T) of 33.64% and FC of 16.52% was taken for investigation. Analytical
techniques such as PSA, XRD, FTIR, Stereo microscopes, and SEM-EDX were employed to characterise the
processed samples. The flotation kinetics study revealed that liberated particles exhibited improved floatability
due to increased surface area and accessibility of target species. With optimised conditions, carbon recovery of
77.6% with 52% FC and iron recovery of 86.6% with 45% Fe(T) was achieved.
Keywords: Blast Furnace Flue Dust, Froth Flotation, Magnetic Separation, Liberation Behaviour.
INTRODUCTION
Blast furnace flue dust (BFD) is one of the wastes gener-
ated in steel plants, which causes a lot of environmental
issues. Significant quantities of flue dust are generated dur-
ing blast furnace operation of hot metal production. Blast
furnace flue dust generally contains fine solid particles
recovered from cleaning the flue gases emerging from blast
furnace operations. It can be recycled as a secondary source
due to its valuable iron and carbon contents. Its genera-
tion is around 25–30 kg per ton of hot metal production
(70–110 kg per ton of steel production), and the utilisation
percentage is limited in steel plants. Typically, a blast fur-
nace dust/sludge contains carbon around 25–40% in the
form of unburnt carbon, iron values 25–40% in the form
of iron-rich grains, gangue and alkali elements like Na, K,
Zn and Pb, which can be utilized as a secondary resource
for recycling [1].
As such use of BFD is challenging in many ways.
Due to its high carbon content, it cannot be pelletized by
directly blending with high-grade ore, as it will have inferior
mechanical strength and reducing properties. The ultrafine
particles of blast furnace flue dust cannot be completely
Enhancing Flotation Kinetics and Magnetic Separation
Efficiency for Iron and Carbon Recovery from Blast Furnace
Flue Dust through Particle Liberation
Deepak Kumar Sahu
CSIR-Institute of Minerals and Materials Technology, Bhubaneswar
G.G. Roy
Indian Institute of Technology, Kharagpur
S.K. Biswal
International PranaGraf Mintech Research Centre, Bhubaneswar
ABSTRACT: The present study investigates the impact of particle liberation on flotation kinetics and magnetic
separation processes, aiming to enhance the recovery and separation of ferruginous and carbonaceous materials
from the blast furnace flue dust. Effect of particle liberation with varying feed size viz. 200, 325 and 500 mesh sizes
were evaluated. Optimisation studies were carried out through cell floatation and magnetic separation (LIMS
&WHIMS). A feed sample with Fe(T) of 33.64% and FC of 16.52% was taken for investigation. Analytical
techniques such as PSA, XRD, FTIR, Stereo microscopes, and SEM-EDX were employed to characterise the
processed samples. The flotation kinetics study revealed that liberated particles exhibited improved floatability
due to increased surface area and accessibility of target species. With optimised conditions, carbon recovery of
77.6% with 52% FC and iron recovery of 86.6% with 45% Fe(T) was achieved.
Keywords: Blast Furnace Flue Dust, Froth Flotation, Magnetic Separation, Liberation Behaviour.
INTRODUCTION
Blast furnace flue dust (BFD) is one of the wastes gener-
ated in steel plants, which causes a lot of environmental
issues. Significant quantities of flue dust are generated dur-
ing blast furnace operation of hot metal production. Blast
furnace flue dust generally contains fine solid particles
recovered from cleaning the flue gases emerging from blast
furnace operations. It can be recycled as a secondary source
due to its valuable iron and carbon contents. Its genera-
tion is around 25–30 kg per ton of hot metal production
(70–110 kg per ton of steel production), and the utilisation
percentage is limited in steel plants. Typically, a blast fur-
nace dust/sludge contains carbon around 25–40% in the
form of unburnt carbon, iron values 25–40% in the form
of iron-rich grains, gangue and alkali elements like Na, K,
Zn and Pb, which can be utilized as a secondary resource
for recycling [1].
As such use of BFD is challenging in many ways.
Due to its high carbon content, it cannot be pelletized by
directly blending with high-grade ore, as it will have inferior
mechanical strength and reducing properties. The ultrafine
particles of blast furnace flue dust cannot be completely