Recent Development of EAF Dust
Treating at Shisaka Smelting Co., Ltd.
S. Takaya, N. Kubota, H. Watanabe and T. Kudo
Abstract Shisaka Smelting Co., Ltd. has recovered crude zinc oxide from electric
arc furnace (EAF) dust using the Waelz kiln process since 1977. When the operation
started, malfunctions frequently occurred in a granulation process which was previous process of a reduction roasting process. We stopped this process and shifted to
the process directly charging EAF dust in the reduction rotary kiln. As a result, we
had been weak in treating high-zinc EAF dust for a long time. To improve the disadvantage, we introduced a new granulation process which is off-line in 2011. Thereby,
zinc recovery rate in reduction rotary kiln greatly increases and the capacity treating
high-zinc EAF dust reaches 50,000 tons per year.
Keywords EAF dust · Zinc recycling · Waelz kiln process · Pelletizing
Introduction
In 1977, Shisaka Smelting Co., Ltd. of the Sumitomo Metal Mining (SMM) Group
started zinc and lead recycling operations using the Waelz process to recover zinc
and lead from dust generated in an electric arc furnace (EAF dust) as crude zinc
oxide pellets for use in an ISP smelter. As shown in Fig. 1, the EAF dust process in
our plant is performed using a reduction rotary kiln (RRK), a Waelz dust washing
and dewatering process, and a drying rotary kiln (DRK). Figure 2 shows the yearly
amounts of EAF dust treated since we started operations in 1977 using a system with
one RRK, washing facilities, and one DRK. At that time, the EAF dust treatment
capacity was 50,000 tons per year. The addition of another RRK in 1992 increased the
capacity to 120,000 tons per year. Recent economic recessions reduced the amount
of incoming EAF dust, resulting in average throughput of about 80,000 tons per year.
The residue left upon volatilization and separation of zinc from EAF dust due to the
addition of a reducing agent to the RRK is called clinker, which is either recycled as
an iron source or disposed of by landfilling. The 2–3% zinc remaining in the clinker
S. Takaya (B) · N. Kubota · H. Watanabe · T. Kudo
Shisaka Smelting Co., Ltd., 3-5-3, Nishibara-Cho, 792-0011 Niihama, Ehime, Japan
e-mail: satoru.takaya.c3@smm-g.com
© The Minerals, Metals & Materials Society 2020
A. Siegmund et al. (eds.), PbZn 2020: 9th International Symposium
on Lead and Zinc Processing, The Minerals, Metals & Materials Series,
https://doi.org/10.1007/978-3-030-37070-1_8
91
Treating at Shisaka Smelting Co., Ltd.
S. Takaya, N. Kubota, H. Watanabe and T. Kudo
Abstract Shisaka Smelting Co., Ltd. has recovered crude zinc oxide from electric
arc furnace (EAF) dust using the Waelz kiln process since 1977. When the operation
started, malfunctions frequently occurred in a granulation process which was previous process of a reduction roasting process. We stopped this process and shifted to
the process directly charging EAF dust in the reduction rotary kiln. As a result, we
had been weak in treating high-zinc EAF dust for a long time. To improve the disadvantage, we introduced a new granulation process which is off-line in 2011. Thereby,
zinc recovery rate in reduction rotary kiln greatly increases and the capacity treating
high-zinc EAF dust reaches 50,000 tons per year.
Keywords EAF dust · Zinc recycling · Waelz kiln process · Pelletizing
Introduction
In 1977, Shisaka Smelting Co., Ltd. of the Sumitomo Metal Mining (SMM) Group
started zinc and lead recycling operations using the Waelz process to recover zinc
and lead from dust generated in an electric arc furnace (EAF dust) as crude zinc
oxide pellets for use in an ISP smelter. As shown in Fig. 1, the EAF dust process in
our plant is performed using a reduction rotary kiln (RRK), a Waelz dust washing
and dewatering process, and a drying rotary kiln (DRK). Figure 2 shows the yearly
amounts of EAF dust treated since we started operations in 1977 using a system with
one RRK, washing facilities, and one DRK. At that time, the EAF dust treatment
capacity was 50,000 tons per year. The addition of another RRK in 1992 increased the
capacity to 120,000 tons per year. Recent economic recessions reduced the amount
of incoming EAF dust, resulting in average throughput of about 80,000 tons per year.
The residue left upon volatilization and separation of zinc from EAF dust due to the
addition of a reducing agent to the RRK is called clinker, which is either recycled as
an iron source or disposed of by landfilling. The 2–3% zinc remaining in the clinker
S. Takaya (B) · N. Kubota · H. Watanabe · T. Kudo
Shisaka Smelting Co., Ltd., 3-5-3, Nishibara-Cho, 792-0011 Niihama, Ehime, Japan
e-mail: satoru.takaya.c3@smm-g.com
© The Minerals, Metals & Materials Society 2020
A. Siegmund et al. (eds.), PbZn 2020: 9th International Symposium
on Lead and Zinc Processing, The Minerals, Metals & Materials Series,
https://doi.org/10.1007/978-3-030-37070-1_8
91