540
W. Cui et al.
particles carried by the process gas into the gas cleaning system. With more and
more restricted environmental legislations, copper smelter dusts are getting serious
attention due to their high concentrations of toxic elements such as As, Bi, Pb, and
Sb.
The flue dusts consist of valuable metals including Cu, Bi, Zn, and Pb that need
to be recovered. Common practice has been to recycle these dusts to the smelting
and converting furnaces to recover the copper content [2]. However, this approach
also recycles and concentrates the harmful impurities. The levels of these impurities
increase as well and this eventually results in high impurity levels in the blister copper
and makes electrolytic refining more difficult. In addition, the recycling of these dusts
also decreases the productivity. As impurity levels in copper concentrates increase,
numerous hydrometallurgical processes mainly acid leaching have been developed
to treat copper smelter dusts [3–6]. Ammoniacal leaching was also proposed for pelletised and roasted flue dusts [7]. However, these hydrometallurgy-based approaches
are not suitable for high-Pb dusts. Pb can be as high as 26 wt% in the ESP dust [8].
Lead sulfide from the copper concentrates is converted to oxide and sulphate in the
dusts collected during smelting and converting processes and they are difficult to be
leached and filtered. The pyrometallurgical approach has been confirmed to be the
only way to efficiently treat the high-Pb dusts. Noranda treated their high-Pb flue
dusts from the copper smelters by adding the dusts to the lead sinter plant [9]. However, the capacity to treat the dust was limited due to heat balance and minor elements
control. Moldabayeva et al. [10] did a laboratory study to treat Pb-containing dusts
from copper smelters at 1100–1175 °C. They used charcoal and coke as reducing
agents, Na 2 SO 4 and Na 2 CO 3 as flux. The products were crude lead, soda-based slag
containing copper, lead and zinc, and secondary dust containing Cd, Pb, Zn, and
Re. Lead was not fully recovered, and the slag and dust generated were required
for further treatment. A combined hydro- and pyrometallurgy two-stage process was
proposed to treat copper converter dust [11]. The hydrometallurgical treatment by
NaOH solution was undertaken for removal of sulfate sulfur and then carbothermal
reduction of desulphated dust at 900 °C in a soda ash melt to recover valuable elements. However, 80% of the copper was reported to the secondary dust which is not
acceptable. Xu et al. [12] also proposed a combined hydro- and pyrometallurgy twostage process to treat high-As and high-Pb dust generated from copper IsaSmelting
furnace. The dust was first leached by H 2 SO 4 to dissolve Cu, Zn, and As with Cd,
Pb, and Bi remained in the residue. The residue was treated in a blast furnace with
additions of coke, lime, and iron ore. Pb and Bi were recovered in the alloy and a
large amount of secondary dust was generated for further treatment.
Dongying Fangyuan Nonferrous Metals successfully developed bottom-blown
copper smelting technology in 2008 which demonstrated a number of advantages
[13, 14]. It is suitable for a wide range of copper, gold, and silver concentrates
with minimal feed preparation. Low-temperature operation and high-pressure gas
injection enable high energy efficiency and productivity. This technology was further developed to a simplified copper-making process including two furnaces which
is again the first process of this kind in the world [15]. Based on the deep understanding and extensive operating experience of the new bath smelting furnace, the
W. Cui et al.
particles carried by the process gas into the gas cleaning system. With more and
more restricted environmental legislations, copper smelter dusts are getting serious
attention due to their high concentrations of toxic elements such as As, Bi, Pb, and
Sb.
The flue dusts consist of valuable metals including Cu, Bi, Zn, and Pb that need
to be recovered. Common practice has been to recycle these dusts to the smelting
and converting furnaces to recover the copper content [2]. However, this approach
also recycles and concentrates the harmful impurities. The levels of these impurities
increase as well and this eventually results in high impurity levels in the blister copper
and makes electrolytic refining more difficult. In addition, the recycling of these dusts
also decreases the productivity. As impurity levels in copper concentrates increase,
numerous hydrometallurgical processes mainly acid leaching have been developed
to treat copper smelter dusts [3–6]. Ammoniacal leaching was also proposed for pelletised and roasted flue dusts [7]. However, these hydrometallurgy-based approaches
are not suitable for high-Pb dusts. Pb can be as high as 26 wt% in the ESP dust [8].
Lead sulfide from the copper concentrates is converted to oxide and sulphate in the
dusts collected during smelting and converting processes and they are difficult to be
leached and filtered. The pyrometallurgical approach has been confirmed to be the
only way to efficiently treat the high-Pb dusts. Noranda treated their high-Pb flue
dusts from the copper smelters by adding the dusts to the lead sinter plant [9]. However, the capacity to treat the dust was limited due to heat balance and minor elements
control. Moldabayeva et al. [10] did a laboratory study to treat Pb-containing dusts
from copper smelters at 1100–1175 °C. They used charcoal and coke as reducing
agents, Na 2 SO 4 and Na 2 CO 3 as flux. The products were crude lead, soda-based slag
containing copper, lead and zinc, and secondary dust containing Cd, Pb, Zn, and
Re. Lead was not fully recovered, and the slag and dust generated were required
for further treatment. A combined hydro- and pyrometallurgy two-stage process was
proposed to treat copper converter dust [11]. The hydrometallurgical treatment by
NaOH solution was undertaken for removal of sulfate sulfur and then carbothermal
reduction of desulphated dust at 900 °C in a soda ash melt to recover valuable elements. However, 80% of the copper was reported to the secondary dust which is not
acceptable. Xu et al. [12] also proposed a combined hydro- and pyrometallurgy twostage process to treat high-As and high-Pb dust generated from copper IsaSmelting
furnace. The dust was first leached by H 2 SO 4 to dissolve Cu, Zn, and As with Cd,
Pb, and Bi remained in the residue. The residue was treated in a blast furnace with
additions of coke, lime, and iron ore. Pb and Bi were recovered in the alloy and a
large amount of secondary dust was generated for further treatment.
Dongying Fangyuan Nonferrous Metals successfully developed bottom-blown
copper smelting technology in 2008 which demonstrated a number of advantages
[13, 14]. It is suitable for a wide range of copper, gold, and silver concentrates
with minimal feed preparation. Low-temperature operation and high-pressure gas
injection enable high energy efficiency and productivity. This technology was further developed to a simplified copper-making process including two furnaces which
is again the first process of this kind in the world [15]. Based on the deep understanding and extensive operating experience of the new bath smelting furnace, the