1664 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
As the demand for EAF steels increases, generation of
electric arc furnace dust (EAFD), a by-product of the EAF
steelmaking, is also expected to increase. For every ton of
steel produced, approximately 10–20 kg of EAFD, which
contains mainly zinc (10–25% Zn) and iron (15–45% Fe),
is generated (Da Silva et al., 2008 De Buzin et al., 2017
Wang et al., 2021). Due to its very fine particle size and
heavy metal content such as lead, cadmium, and chro-
mium, EAFD is classified as a hazardous waste in many
countries such as Japan, Europe, and USA (US EPA, 1991
European Agency for Safety and Health at Work, 2006).
With 7.8 million tons generated in 2019 alone, EAFD
management poses a significant challenge as steel produc-
tion continues to rise.
Recognizing the potential of EAFD as a secondary
resource for zinc and iron, development of a practical
dust treatment process has become crucial for a sustain-
able “waste-to-raw material” strategy, aligning with the
principles of a circular economy. Currently, pyrometal-
lurgical processes, such as the Waelz kiln process, (Anon,
1989 Strohmeier and Bonestell, 1996), the Rotary Hearth
Furnace (RHF) method (Tsutsumi et al., 2010), and the
Primus method (Nakayama and Taniishi, 2011 Nakayama,
2012) have dominated EAFD treatment for zinc recovery.
However, strictly pyrometallurgical methods are usually
carbon-intensive, have high energy consumption, and
require large operational costs.
Consequently, hydrometallurgical processes, known
for their lower environmental impact, reduced energy con-
sumption, and lower costs, are gaining attention as a more
sustainable alternative to extract zinc and iron from EAFD
(Binnemans et al., 2020 Antuñano et al., 2019 Pickles,
2009 Havlik et al., 2006). However, the efforts to develop
hydrometallurgical methods also face challenges, particu-
larly due to the insoluble nature of the primary zinc-bear-
ing compound in EAFD, zinc ferrite (ZnFe2O4), in both
acidic and alkaline media (Langová and Matýsek, 2010
Youcai and Stanforth, 2000). Hence, research efforts are
now focused on developing strategies to convert insoluble
ZnFe2O4 into readily soluble ZnO.
In this work, the combination of a non-carbothermic
pyrometallurgical CaO addition treatment and hydromet-
allurgical alkaline leaching to recover zinc and iron from
EAFD as a promising alternative to strictly pyrometal-
lurgical or hydrometallurgical processes will be presented
(Gamutan et al., 2024). The flowsheet of the proposed pro-
cess is shown in Figure 1.
Figure 1. Flowsheet of the proposed CaO-treatment process and alkaline leaching for zinc and
iron recycling from EAFD
As the demand for EAF steels increases, generation of
electric arc furnace dust (EAFD), a by-product of the EAF
steelmaking, is also expected to increase. For every ton of
steel produced, approximately 10–20 kg of EAFD, which
contains mainly zinc (10–25% Zn) and iron (15–45% Fe),
is generated (Da Silva et al., 2008 De Buzin et al., 2017
Wang et al., 2021). Due to its very fine particle size and
heavy metal content such as lead, cadmium, and chro-
mium, EAFD is classified as a hazardous waste in many
countries such as Japan, Europe, and USA (US EPA, 1991
European Agency for Safety and Health at Work, 2006).
With 7.8 million tons generated in 2019 alone, EAFD
management poses a significant challenge as steel produc-
tion continues to rise.
Recognizing the potential of EAFD as a secondary
resource for zinc and iron, development of a practical
dust treatment process has become crucial for a sustain-
able “waste-to-raw material” strategy, aligning with the
principles of a circular economy. Currently, pyrometal-
lurgical processes, such as the Waelz kiln process, (Anon,
1989 Strohmeier and Bonestell, 1996), the Rotary Hearth
Furnace (RHF) method (Tsutsumi et al., 2010), and the
Primus method (Nakayama and Taniishi, 2011 Nakayama,
2012) have dominated EAFD treatment for zinc recovery.
However, strictly pyrometallurgical methods are usually
carbon-intensive, have high energy consumption, and
require large operational costs.
Consequently, hydrometallurgical processes, known
for their lower environmental impact, reduced energy con-
sumption, and lower costs, are gaining attention as a more
sustainable alternative to extract zinc and iron from EAFD
(Binnemans et al., 2020 Antuñano et al., 2019 Pickles,
2009 Havlik et al., 2006). However, the efforts to develop
hydrometallurgical methods also face challenges, particu-
larly due to the insoluble nature of the primary zinc-bear-
ing compound in EAFD, zinc ferrite (ZnFe2O4), in both
acidic and alkaline media (Langová and Matýsek, 2010
Youcai and Stanforth, 2000). Hence, research efforts are
now focused on developing strategies to convert insoluble
ZnFe2O4 into readily soluble ZnO.
In this work, the combination of a non-carbothermic
pyrometallurgical CaO addition treatment and hydromet-
allurgical alkaline leaching to recover zinc and iron from
EAFD as a promising alternative to strictly pyrometal-
lurgical or hydrometallurgical processes will be presented
(Gamutan et al., 2024). The flowsheet of the proposed pro-
cess is shown in Figure 1.
Figure 1. Flowsheet of the proposed CaO-treatment process and alkaline leaching for zinc and
iron recycling from EAFD