658
P. Xin et al.
Table 2 Antimony smelting slag composition (wt%)
Pb
Zn
Sb
S
Fe
SiO 2
CaO
Sample 1
1.16
5.59
1.2
1.65
20.15
22.18
17.52
Sample 2
1.32
7.56
1.42
1.42
21.03
22.32
20.66
Average
1.24
6.58
1.31
1.54
20.59
22.25
19.09
Table 3 Production data
Duration (min) Boiler
evaporation
(t/h)
Air (m 3 /h)
Pulverized
coal (t/h)
λ
Feeding and
melting
70–75
7.6–7.7
12,000–12,500 ~1.7
0.89
Fuming
60
9.5–10
11,500–12,000 ~2.0
0.72
Slag tapping
12–20
7.1–7.2
11,500–12,500 ~1.6
0.94
In operation, 15–16 t will be fed into fuming furnace per campaign. According
to the production process experience,the duration of materials feeding is around 70–
75 min. The period of fuming is around 60 min, and the slag tapping duration is
15–20 min. The temperature of molten bath is 1250–1300 °C. The other production
data is shown in Table 3.
The atmosphere within fuming furnace is controlled by adjusting the amount of
coal fed to fuming furnace to ensure the speed of melting and reduction reaction. In
Table 3, production data shows cycle of fuming furnace boiler operation. For fuming
stage, more coal is fed into fuming furnace and more reaction heat is produced, so
boiler evaporation is more. The coal consumption is ~0.3 t per ton antimony smelting
slag.
ZnO dust is the main product of fuming reaction. ZnO dust will go to waste
heater boiler, surface cooler, and bag filter and be collected by these facilities. The
composition of dust collected by such three facilities is shown in Table 4.
In accordance with production data, Pb content in the dust collected from waste
heat boiler, surface cooler, and bag filter is reduced gradually; the reduced percentage
is 0.12% and 0.13%, respectively. However, zinc content in the dust collected from
bag filter is higher than that dust collected from boiler and surface cooler. The reason
is that dust collected from boiler and surface cooler is by gravity and lead oxides are
heavier than zinc oxides. The assays of dust in above table show that Fe, SiO 2 , and
Table 4 Composition of dust collected by waste heater boiler, surface cooler, and bag filter
Pb
Zn
Sb
S
Fe
SiO 2
CaO
WHB
9.38
43.53
2.77
2.41
4.57
7.61
2.76
SC
9.29
42.13
8.42
3.13
1.24
2.19
0.68
BF
9.16
46.55
8.03
3.62
0.98
1.73
0.57
P. Xin et al.
Table 2 Antimony smelting slag composition (wt%)
Pb
Zn
Sb
S
Fe
SiO 2
CaO
Sample 1
1.16
5.59
1.2
1.65
20.15
22.18
17.52
Sample 2
1.32
7.56
1.42
1.42
21.03
22.32
20.66
Average
1.24
6.58
1.31
1.54
20.59
22.25
19.09
Table 3 Production data
Duration (min) Boiler
evaporation
(t/h)
Air (m 3 /h)
Pulverized
coal (t/h)
λ
Feeding and
melting
70–75
7.6–7.7
12,000–12,500 ~1.7
0.89
Fuming
60
9.5–10
11,500–12,000 ~2.0
0.72
Slag tapping
12–20
7.1–7.2
11,500–12,500 ~1.6
0.94
In operation, 15–16 t will be fed into fuming furnace per campaign. According
to the production process experience,the duration of materials feeding is around 70–
75 min. The period of fuming is around 60 min, and the slag tapping duration is
15–20 min. The temperature of molten bath is 1250–1300 °C. The other production
data is shown in Table 3.
The atmosphere within fuming furnace is controlled by adjusting the amount of
coal fed to fuming furnace to ensure the speed of melting and reduction reaction. In
Table 3, production data shows cycle of fuming furnace boiler operation. For fuming
stage, more coal is fed into fuming furnace and more reaction heat is produced, so
boiler evaporation is more. The coal consumption is ~0.3 t per ton antimony smelting
slag.
ZnO dust is the main product of fuming reaction. ZnO dust will go to waste
heater boiler, surface cooler, and bag filter and be collected by these facilities. The
composition of dust collected by such three facilities is shown in Table 4.
In accordance with production data, Pb content in the dust collected from waste
heat boiler, surface cooler, and bag filter is reduced gradually; the reduced percentage
is 0.12% and 0.13%, respectively. However, zinc content in the dust collected from
bag filter is higher than that dust collected from boiler and surface cooler. The reason
is that dust collected from boiler and surface cooler is by gravity and lead oxides are
heavier than zinc oxides. The assays of dust in above table show that Fe, SiO 2 , and
Table 4 Composition of dust collected by waste heater boiler, surface cooler, and bag filter
Pb
Zn
Sb
S
Fe
SiO 2
CaO
WHB
9.38
43.53
2.77
2.41
4.57
7.61
2.76
SC
9.29
42.13
8.42
3.13
1.24
2.19
0.68
BF
9.16
46.55
8.03
3.62
0.98
1.73
0.57