1716 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
rate of 5 mL/min, using a syringe pump (SyringeSix:1600
New Era Pump Systems). The concentration of acetone,
which exhibits good miscibility with water and signifi-
cantly reduces the solubility of vanadium salts in a mixed
solvent system, was varied by dilution with Millipore
water to between 80–100% acetone (v/v). Table 1 shows
the various acetone concentrations which were added to
the LSL in proportions corresponding to different final
organic-to-aqueous (O/A) volumetric ratios. The kinetics
and approximation of equilibrium of the batch system was
initially evaluated by running the crystallization process for
96 h. The aqueous metal concentrations over this period
were determined from weighed samples (circa. 1 g) taken at
batch time (tb) intervals of 1, 2, 4, 6, 24, 48, 72 and 96 h
to understand the variation of yield and purity with time.
A balance between industrially viable batch times
and a better understanding of the system was explored by
limiting the overall batch time to 6 h. Time related crystal
habit changes were investigated by taking slurry samples at
a specific tb, and quickly analyzing them with a light micro-
scope (Olympus BH2 at 20× magnification). The aqueous
component, taken at a specific tb, was filtered with a 0.22
µm syringe filter and the solids free solution was diluted
to the desired factor using 2% HNO3 and then used for
ICP-OES (Thermo Scientific iCAP 7000 Plus coupled to
an autosampler Cetac ASX-520) analysis for concentration
determination. The recovery (%)was determined using
equation 1.
C V
C V C V
%Recovery
i i
i i t t =
-
(1)
where Ci and Vi are the initial concentration (mg/L) and
volume (L) of the solution and Ct and Vt are the concentra-
tions (mg/L) and volume of solution obtained at time tb.
At the end of the batch, the experiment was stopped, the
Figure 1. Reactor setup
rate of 5 mL/min, using a syringe pump (SyringeSix:1600
New Era Pump Systems). The concentration of acetone,
which exhibits good miscibility with water and signifi-
cantly reduces the solubility of vanadium salts in a mixed
solvent system, was varied by dilution with Millipore
water to between 80–100% acetone (v/v). Table 1 shows
the various acetone concentrations which were added to
the LSL in proportions corresponding to different final
organic-to-aqueous (O/A) volumetric ratios. The kinetics
and approximation of equilibrium of the batch system was
initially evaluated by running the crystallization process for
96 h. The aqueous metal concentrations over this period
were determined from weighed samples (circa. 1 g) taken at
batch time (tb) intervals of 1, 2, 4, 6, 24, 48, 72 and 96 h
to understand the variation of yield and purity with time.
A balance between industrially viable batch times
and a better understanding of the system was explored by
limiting the overall batch time to 6 h. Time related crystal
habit changes were investigated by taking slurry samples at
a specific tb, and quickly analyzing them with a light micro-
scope (Olympus BH2 at 20× magnification). The aqueous
component, taken at a specific tb, was filtered with a 0.22
µm syringe filter and the solids free solution was diluted
to the desired factor using 2% HNO3 and then used for
ICP-OES (Thermo Scientific iCAP 7000 Plus coupled to
an autosampler Cetac ASX-520) analysis for concentration
determination. The recovery (%)was determined using
equation 1.
C V
C V C V
%Recovery
i i
i i t t =
-
(1)
where Ci and Vi are the initial concentration (mg/L) and
volume (L) of the solution and Ct and Vt are the concentra-
tions (mg/L) and volume of solution obtained at time tb.
At the end of the batch, the experiment was stopped, the
Figure 1. Reactor setup