2.2 Single-stage extraction
procedures
The extraction experiments were conducted and duplicated in separatory
funnels. At ambient temperature (293±1 K), a mixture containing a
certain volume of the aqueous and organic phase was subjected to
mechanical vibration at 300 r/min, and then let it stand until the two
phases separated. Contact time was selected after preliminary extraction
experiments, for a period of 10 min, which was found enough for
equilibrium. Then, the aqueous and organic samples were collected for
further analysis.
The organic solution used in all experiments was composed of 0.4 mol/L
TMPD dissolved in CCl4, and the phase ratio was 1/1
(O/A), except when explicitly described otherwise. In order to
investigate the effects of pH, the concentration of
H3BO3 and the concentration of
MgCl2 on boron extraction, three simulated brines (which
are listed in Table 2) were prepared, respectively, while the filtered
SL brine (given in Table 1) was used in the experiment of other factors,
including the concentration of TMPD, the phase ratio (O/A) and the
temperature. All single factor experiments were performed at room
temperature, except when studying the effect of temperature, according
to procedures described above.
Table 2. Main characteristics of the simulated brines.