Leaching of Turkish Oxidized Pb–Zn Flotation Tailings …
467
Fig. 5 Metal dissolutions with 1.0 M malic acid at 80 °C and 1/10 S/L ratio
Tartaric Acid (TA) Leach
The effects of 1.0 M TA at 80 °C leaching temperature and 1/10 S/L ratio were
determined. 34% Zn dissolution at 30 min and 32% Zn dissolution at 180 min were
obtained. Metal dissolution order was Zn > Pb > Fe. Maximum Zn dissolution was
achieved at 30 min with 10% Pb and 4.2% Fe dissolutions. Tartaric acid was not a
good leach reagent for our purposes. pH was almost constant at 2 for all leaching
times.
Conclusions
Table 10 compares and summarizes the optimum leaching results and conditions with
respect to maximum Zn dissolution and minimum impurity co-dissolutions using
inorganic and organic acids tested in this study. At 1.0 M H 2 SO 4 , HCl, citric, and
Table 10 Summary and comparison of optimum leaching results
Reagent
Metal Dissol. Order
pH
Max. Zn
Dissol.
Pb/Ag
Dissol.
Selectivity
(Zn-Fe) / (Fe-Zn)
Selectivity
(Zn-As) / (As-Zn)
Optim. Conditions
Conc., S/L, T, t
H2SO4
Zn>Fe>As>Pb
0.5-1.0
92 %
0%Pb
0%Ag
80%
72%
1M, 1/10, 40
o
C,
60 min
HCl
Zn>Pb>Fe
92%
10% Pb
0% Ag
82%
1M, 1/10, 80
o
C,
30 min
Malic acid
Zn>Pb>Fe
2.3
91.6%
8.1%
85%
1M, 1/10, 80
o
C,
180 min
Citric acid
Zn>Fe>As>Pb
2.0-3.0
91.0%
12%
72%
74%
1M, 1/10, 80
o
C,
180 min
Formic acid
Zn>Pb>Fe
3.0
82.6%
2.8%
82%
1M, 1/10, 60
o
C,
180 min
Oxalic acid
Fe>As>Pb>Zn
0.7-0.9
2.9%
3.2%
93.1%
66.1%
1M, 1/10, 60
o
C,
180 min
Tartaric acid
Zn>Pb>Fe
2.0
34.4%
10%
30.2%
1M, 1/10, 80
o
C,
30 min
Ascorbic acid
Zn>Fe>As>Pb
3.5-3.7
32%
3%
19%
23%
1M, 1/10, 60
o
C,
60 min