Zinc Recovery of Low Grade Concentrate from Vazante Mine …
233
Table 1 Chemical analysis
of the raw materials
Element
Low grade concentrate (%)
EAFD (%)
Fe
10.29
29.24
Zn
16.58
18.34
Pb
0.46
1.58
Al
0.49
0.28
Mg
7.12
2.36
Ca
9.77
2.33
C
6.10
6.72
Cd
0.04
0.18
CaO
13.67
3.26
Al 2 O 3
0.91
0.53
SiO 2
12.94
3.02
MgO
11.89
3.95
with an infrared thermometer (model TI-920, Instrutherm), while the temperatures
of the dust catcher, cyclone, and bag filter were measured by thermocouples.
For heating the furnace, an LPG gas burner is used; the feed of the coke feedstock
is started as soon as the internal temperature of the furnace reaches 600 °C. Figure 1
shows the layout of Nexa Juiz de Fora pilot plant. The range of temperature inside
the furnace was 1000–1100 °C, and the residence time was 6–7 h; those parameters
meet the industrial process parameters.
Fig. 1 Picture of the pilot scale Waelz kiln with its main components
233
Table 1 Chemical analysis
of the raw materials
Element
Low grade concentrate (%)
EAFD (%)
Fe
10.29
29.24
Zn
16.58
18.34
Pb
0.46
1.58
Al
0.49
0.28
Mg
7.12
2.36
Ca
9.77
2.33
C
6.10
6.72
Cd
0.04
0.18
CaO
13.67
3.26
Al 2 O 3
0.91
0.53
SiO 2
12.94
3.02
MgO
11.89
3.95
with an infrared thermometer (model TI-920, Instrutherm), while the temperatures
of the dust catcher, cyclone, and bag filter were measured by thermocouples.
For heating the furnace, an LPG gas burner is used; the feed of the coke feedstock
is started as soon as the internal temperature of the furnace reaches 600 °C. Figure 1
shows the layout of Nexa Juiz de Fora pilot plant. The range of temperature inside
the furnace was 1000–1100 °C, and the residence time was 6–7 h; those parameters
meet the industrial process parameters.
Fig. 1 Picture of the pilot scale Waelz kiln with its main components