860
H. Wang et al.
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Fig. 9 Effect of leaching temperature on leaching rate of Zn and Fe
0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 1.25 1.30
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Fig. 10 Effect of H 2 SO 4 /Zn on leaching rate of Zn and Fe
It is obvious in Fig. 10 that the zinc leaching rate increases with the ratio of
H 2 SO 4 /Zn. When the ratio of H 2 SO 4 /Zn increases to 1.2:1, the zinc leaching rate
curve tends to be gentle and the increment became smaller. The zinc leaching rate
reaches 97.7%. Therefore, the best ratio of H 2 SO 4 /Zn for zinc leaching rate is 1.2:1.
The iron leaching rate also increases with the H 2 SO 4 /Zn ratio, but in a different way.
When the H 2 SO 4 /Zn ratio increases from 0.9 to 1.1, the iron leaching rate gradually
increases and reaches 12.5%. When the H 2 SO 4 /Zn ratio continues to increase, the
iron leaching rate is enhanced dramatically to 72.6%. Since the zinc leaching rate is