1663
Combined Pyro and Hydrometallurgical Treatment of EAF Dust
for Zinc and Iron Recycling
Jonah Gamutan, Richard Alorro
WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Australia
Shunsuke Koide
Hoei Metal Co., Ltd., 66 Teraike, Tsutsumi-cho, Toyota, Japan
Yasushi Sasaki, Tetsuya Nagasaka
New Industry Creation Hatchery Center, Tohoku University, Japan
ABSTRACT: The global transition towards clean energy is expected to drive the demand for zinc and iron—
vital components to produce galvanized steel for wind power generation. In this work, a combination of
CaO addition treatment and alkaline leaching to recover zinc and iron from electric arc furnace (EAF) dust is
presented. Insoluble ZnFe2O4 is first converted to soluble ZnO by reacting with CaO at 1100°C. Followed by
leaching in a 2M NaOH solution at 70°C, up to 98% of zinc in the dust is recovered, and an iron-rich solid
byproduct for reuse in the steelmaking process is also generated.
INTRODUCTION
The global transition towards clean energy is expected to
drive the demand for zinc and iron, vital components to
produce galvanized steel for use in transportation, infra-
structure, and power generation. At present, both zinc and
iron are produced mostly from primary zinc and iron ores
using various metallurgical processes. Metallic zinc, for
example, is usually produced via a roasting and smelting
process from sulphide ores and via a leaching and electro-
winning process from oxide ores. Steels, on the other hand,
are mainly produced via the blast furnace—basic oxygen
furnace (BF-BOF) route using primary iron ores or via the
electric arc furnace (EAF) route using recycled end-of-life
steel scrap.
At present, the global production of steels via the EAF
route is rapidly increasing due to efficiency and minimal
GHG emissions compared to the traditional BF-BOF
route. EAF steelmaking does not require coke and employs
end-of-life steel scrap or direct reduced iron (DRI) as raw
material to the process, thus offering an excellent alterna-
tive to the carbon-intensive BF-BOF process ahead of green
steelmaking technologies that are yet to be commercialized.
The World Steel Association reported a substantial growth
in global EAF steel production, reaching 518 million tons
in 2019, a 173-million-ton increase compared to a decade
earlier (World Steel Association, 2020). Moving forward,
the global share of EAF steel production is expected to
increase from the current 30% to more than 50% by 2050
(International Energy Agency, 2020). Driven by the need
to comply with the global call for decarbonization while
meeting growing demands for steel products, this trend is
expected to continue in the future.
Combined Pyro and Hydrometallurgical Treatment of EAF Dust
for Zinc and Iron Recycling
Jonah Gamutan, Richard Alorro
WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Australia
Shunsuke Koide
Hoei Metal Co., Ltd., 66 Teraike, Tsutsumi-cho, Toyota, Japan
Yasushi Sasaki, Tetsuya Nagasaka
New Industry Creation Hatchery Center, Tohoku University, Japan
ABSTRACT: The global transition towards clean energy is expected to drive the demand for zinc and iron—
vital components to produce galvanized steel for wind power generation. In this work, a combination of
CaO addition treatment and alkaline leaching to recover zinc and iron from electric arc furnace (EAF) dust is
presented. Insoluble ZnFe2O4 is first converted to soluble ZnO by reacting with CaO at 1100°C. Followed by
leaching in a 2M NaOH solution at 70°C, up to 98% of zinc in the dust is recovered, and an iron-rich solid
byproduct for reuse in the steelmaking process is also generated.
INTRODUCTION
The global transition towards clean energy is expected to
drive the demand for zinc and iron, vital components to
produce galvanized steel for use in transportation, infra-
structure, and power generation. At present, both zinc and
iron are produced mostly from primary zinc and iron ores
using various metallurgical processes. Metallic zinc, for
example, is usually produced via a roasting and smelting
process from sulphide ores and via a leaching and electro-
winning process from oxide ores. Steels, on the other hand,
are mainly produced via the blast furnace—basic oxygen
furnace (BF-BOF) route using primary iron ores or via the
electric arc furnace (EAF) route using recycled end-of-life
steel scrap.
At present, the global production of steels via the EAF
route is rapidly increasing due to efficiency and minimal
GHG emissions compared to the traditional BF-BOF
route. EAF steelmaking does not require coke and employs
end-of-life steel scrap or direct reduced iron (DRI) as raw
material to the process, thus offering an excellent alterna-
tive to the carbon-intensive BF-BOF process ahead of green
steelmaking technologies that are yet to be commercialized.
The World Steel Association reported a substantial growth
in global EAF steel production, reaching 518 million tons
in 2019, a 173-million-ton increase compared to a decade
earlier (World Steel Association, 2020). Moving forward,
the global share of EAF steel production is expected to
increase from the current 30% to more than 50% by 2050
(International Energy Agency, 2020). Driven by the need
to comply with the global call for decarbonization while
meeting growing demands for steel products, this trend is
expected to continue in the future.