Effect of concentration of TOA and TBP on the extraction
yields
The effect of TOA concentration varying in the range of
25–50 vol.% on the extraction yields of Fe(III) and sulfuric acid were
studied. The experimental results plotted in Fig. 2 illustrates that
the extraction yields of Fe (III) and sulfuric acid increase rapidly
from 68.2% and 92.6% to 87.0% and 96.6% respectively with the
increase of TOA concentration range from 25% to 35%. When the
TOA concentration exceeds 35%, the extraction yields of Fe(III) and
sulfuric acid increase slightly. At a fixed phase ratio (O/A) of 1:1
and the initial concentration of Fe(III) and sulfuric acid,the increase
of the amount of extractant leads to the increase of the TOA concentrations,
which helps to increase the extraction yields of Fe (III)
and sulfuric acid. The extractant concentration is generally no more
than 40 vol.%; otherwise, the viscosity of the organic phase will
sharply rise, which is harmful for phase separation.