4
suppressant to access solubility. ACORGA EW98 was pres-
ent in the aqueous phase at expected concentrations with
no indication of presence in the organic phase.
Phase 3—EW Compatibility and Pilot Plant
In December 2023, a continuous SX-EW pilot plant
trial was completed at Syensqo’s Tempe, AZ laboratory.
This pilot plant was set up in a 2E +1S configuration
with 2 extract stages running in series and 1 strip stage.
Additionally the rich electrolyte produced by the solvent
extraction process was used in a small electrowinning cell
consisting of 2 anodes and 1 cathode.
The primary objective of the pilot plant was to confirm
ACORGA ® EW98 acid mist suppressant performance in a
lab scale SX-EW continuous circuit. Additionally, the goal
of the pilot plant test was to confirm adequate SX physical
and metallurgical performance under continuous operating
conditions and confirm the additive retention and stability
in the electrolyte.
Acid mist suppression was measured in a similar way
to the pre-screening test. A piece of filter paper was placed
above the anode/cathode pair for 120 minutes. A 50 mL
sample of DI water was placed in a beaker and the pH was
measured. Following the conclusion of the 120 sampling
time, the filter paper was added to the beaker and mixed for
5 minutes and a final pH was measured. The baseline test-
ing for the pilot plan was run over the first 9 full cycles of
organic through the system. A total of 4 acid mist measure-
ments were taken over the baseline period. Higher acid mist
is indicated by a lower pH from the filter paper analysis.
The pH decreased from a starting point of ~6 to an average
pH of 3 for the baseline run. Acid mist accumulation was
consistent over the baseline period.
ACORGA ® EW98 was then dosed into the electro-
lyte volume at 40 ppm and ran continuously for another
19 cycles. This electrolyte fed SX and EW over the test
period with no additional make-up of the mist suppressant.
During the test period, acid mist accumulation resulted in
an average pH of 5.6 and also very consistent throughout
the trial as shown in Figure 7.
The higher pH over the test period confirmed the acid
mist suppression with the additive. ACORGA ® EW98 pro-
vided substantial acid mist suppression and maintained the
performance throughout the test run.
Metallurgical performance was also monitored and
analyzed during the pilot plant trial. Overall pilot plant
recovery remained constant throughout the trial with
performance of 96% or better with the results shown in
Figure 8. In addition to extraction efficiency, the net trans-
fer also remained consistent throughout the trial and results
are shown in Figure 9.
Lastly, phase disengagement times were measured
throughout the entirety of the pilot plant. No significant
impacts were observed in either the extract or strip phase
disengagement times and the results are shown below in
Figure 10.
Figure 6. IFT results after 5 contacts with a 40 ppm dose of
ACORGA® EW98
Figure 7. Acid mist suppression performance of ACORGA®
EW98 across several contacts in a continuous SX/EW pilot
plant
Figure 8. ACORGA® EW98 pilot plant extraction efficiency
suppressant to access solubility. ACORGA EW98 was pres-
ent in the aqueous phase at expected concentrations with
no indication of presence in the organic phase.
Phase 3—EW Compatibility and Pilot Plant
In December 2023, a continuous SX-EW pilot plant
trial was completed at Syensqo’s Tempe, AZ laboratory.
This pilot plant was set up in a 2E +1S configuration
with 2 extract stages running in series and 1 strip stage.
Additionally the rich electrolyte produced by the solvent
extraction process was used in a small electrowinning cell
consisting of 2 anodes and 1 cathode.
The primary objective of the pilot plant was to confirm
ACORGA ® EW98 acid mist suppressant performance in a
lab scale SX-EW continuous circuit. Additionally, the goal
of the pilot plant test was to confirm adequate SX physical
and metallurgical performance under continuous operating
conditions and confirm the additive retention and stability
in the electrolyte.
Acid mist suppression was measured in a similar way
to the pre-screening test. A piece of filter paper was placed
above the anode/cathode pair for 120 minutes. A 50 mL
sample of DI water was placed in a beaker and the pH was
measured. Following the conclusion of the 120 sampling
time, the filter paper was added to the beaker and mixed for
5 minutes and a final pH was measured. The baseline test-
ing for the pilot plan was run over the first 9 full cycles of
organic through the system. A total of 4 acid mist measure-
ments were taken over the baseline period. Higher acid mist
is indicated by a lower pH from the filter paper analysis.
The pH decreased from a starting point of ~6 to an average
pH of 3 for the baseline run. Acid mist accumulation was
consistent over the baseline period.
ACORGA ® EW98 was then dosed into the electro-
lyte volume at 40 ppm and ran continuously for another
19 cycles. This electrolyte fed SX and EW over the test
period with no additional make-up of the mist suppressant.
During the test period, acid mist accumulation resulted in
an average pH of 5.6 and also very consistent throughout
the trial as shown in Figure 7.
The higher pH over the test period confirmed the acid
mist suppression with the additive. ACORGA ® EW98 pro-
vided substantial acid mist suppression and maintained the
performance throughout the test run.
Metallurgical performance was also monitored and
analyzed during the pilot plant trial. Overall pilot plant
recovery remained constant throughout the trial with
performance of 96% or better with the results shown in
Figure 8. In addition to extraction efficiency, the net trans-
fer also remained consistent throughout the trial and results
are shown in Figure 9.
Lastly, phase disengagement times were measured
throughout the entirety of the pilot plant. No significant
impacts were observed in either the extract or strip phase
disengagement times and the results are shown below in
Figure 10.
Figure 6. IFT results after 5 contacts with a 40 ppm dose of
ACORGA® EW98
Figure 7. Acid mist suppression performance of ACORGA®
EW98 across several contacts in a continuous SX/EW pilot
plant
Figure 8. ACORGA® EW98 pilot plant extraction efficiency