918 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
to ensure a wide analysis range to investigate the potential
impact on plant behavior.
Further insight has been provided with similar test but
using process water (PW) coming from the plant as SW, in
place of DW (Le 2020). Conductivity followed the same
trend as for distilled water, starting with a higher value.
Sulfate concentrations had not been specifically measured.
However, it was observed in the DW tests that the con-
tribution of sulfates to conductivity was approximately
constant. Assuming that this ratio is the same for PW test,
sulfate concentrations were deduced from conductivity
measurements. The model was then simultaneously cali-
brated for DW and PW tests, with the same parameters.
(Figure 4).
Table 2 summarizes the Cmax and k values as well as
fitting errors for DW data, PW data, and both. To enable
comparison with previous fit with DW only, Cmax values
have been kept fixed and only the kinetic constants have
been adjusted.
The increase in sulfate concentration is slightly less
marked on PW curve than for DW, which would indicate
that equilibrium is being approached. In terms of calibra-
tion, this translates into less error at intermediate Cmax val-
ues, and a calibration optimum is clearly apparent. It is thus
possible to calibrate the model correctly for experiments on
PW and DW with the same parameters, indicating that the
dissolution model applies to both waters for sulfates and
that they behave in the same way.
This also indicates that, although dissolution test pro-
vides insight in the dissolution occurring in the slurry, it
cannot provide a full characterization (at least if only DW is
Figure 3. Several acceptable fitting of dissolution test, the name of the dot-lines
reporting to the Fit of Table 1
Table 1. Possible optimal parameters for dissolution test
fitting for sulfates
Fit C
max ,mg/L k, /min Error
DW1 135 432 1.24 10–5 721.7
DW2 10 483 1.63 10–4 737.5
DW3 5 000 3.52 10–4 788.7
DW4 2 000 9.54 10–4 1160.3
DW5 1 000 2.22 10–3 2716.3
Table 2. Calibrated parameters for dissolution test (sulfates)
Fit Cmax, mg/L k, /min on DW on PW Total Error
DW-PW1 135 432 1.13 10–5 3 483.5 2 785.8 6 269.3
DW-PW2 10 483 1.52 10–4 2 416.0 1 843.4 4 259.4
DW-PW3 5 000 3.36 10–4 1 527.3 644.9 2 472.2
Best fit
DW-PW
2 664 6.87 10–4 980.5 247.7 1 228.2
DW-PW4 2 000 9.75 10–4 1 296.3 647.0 1 943.4
DW-PW5 1 000 2.55 10–3 7 085.5 1 6012.6 23 098.1
to ensure a wide analysis range to investigate the potential
impact on plant behavior.
Further insight has been provided with similar test but
using process water (PW) coming from the plant as SW, in
place of DW (Le 2020). Conductivity followed the same
trend as for distilled water, starting with a higher value.
Sulfate concentrations had not been specifically measured.
However, it was observed in the DW tests that the con-
tribution of sulfates to conductivity was approximately
constant. Assuming that this ratio is the same for PW test,
sulfate concentrations were deduced from conductivity
measurements. The model was then simultaneously cali-
brated for DW and PW tests, with the same parameters.
(Figure 4).
Table 2 summarizes the Cmax and k values as well as
fitting errors for DW data, PW data, and both. To enable
comparison with previous fit with DW only, Cmax values
have been kept fixed and only the kinetic constants have
been adjusted.
The increase in sulfate concentration is slightly less
marked on PW curve than for DW, which would indicate
that equilibrium is being approached. In terms of calibra-
tion, this translates into less error at intermediate Cmax val-
ues, and a calibration optimum is clearly apparent. It is thus
possible to calibrate the model correctly for experiments on
PW and DW with the same parameters, indicating that the
dissolution model applies to both waters for sulfates and
that they behave in the same way.
This also indicates that, although dissolution test pro-
vides insight in the dissolution occurring in the slurry, it
cannot provide a full characterization (at least if only DW is
Figure 3. Several acceptable fitting of dissolution test, the name of the dot-lines
reporting to the Fit of Table 1
Table 1. Possible optimal parameters for dissolution test
fitting for sulfates
Fit C
max ,mg/L k, /min Error
DW1 135 432 1.24 10–5 721.7
DW2 10 483 1.63 10–4 737.5
DW3 5 000 3.52 10–4 788.7
DW4 2 000 9.54 10–4 1160.3
DW5 1 000 2.22 10–3 2716.3
Table 2. Calibrated parameters for dissolution test (sulfates)
Fit Cmax, mg/L k, /min on DW on PW Total Error
DW-PW1 135 432 1.13 10–5 3 483.5 2 785.8 6 269.3
DW-PW2 10 483 1.52 10–4 2 416.0 1 843.4 4 259.4
DW-PW3 5 000 3.36 10–4 1 527.3 644.9 2 472.2
Best fit
DW-PW
2 664 6.87 10–4 980.5 247.7 1 228.2
DW-PW4 2 000 9.75 10–4 1 296.3 647.0 1 943.4
DW-PW5 1 000 2.55 10–3 7 085.5 1 6012.6 23 098.1