XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 769
concentrations of SCN, it is imperative that the EO process
operate at lower current density to ensure high current effi-
ciency and overall free CN yield.
Table 3 summarizes the test parameters and the result-
ing current efficiencies.
As shown, there is a significant sensitivity to the process
with changing current density, particularly for actual leach
solutions, which contain additional anions which cause
parasitic reactions to occur on the anode.
CASE STUDY 2: COLD WEATHER MINE
IN ABITIBI REGION
Description of Issue, and Potential for Improvement
As the ore body of the Abitibi Gold Belt example has signif-
icant content of sulfide, the cyanidation process produces
significant concentrations of SCN, which may cause toxic-
ity issues in the receiving environment. Since the site has
a positive water balance, the post detox solution must be
discharged to the environment. To mitigate potential toxic-
ity, the site has a moving bed bioreactor (MBBR) installed
to oxidize the thiospecies to sulphate prior to release to the
environment. While an accepted technology, the MBBR
does contain some inherent downsides, particularly for this
site, namely:
• Cold, northern climate
To ensure sufficient biological activity, the bioreac-
tors and incoming solution needs to be heated, add-
ing significant costs to the treatment.
Figure 6. Variation of (a) thiocyanate concentration and (b) cyanide concentration with and without initial free cyanide.
Conditions: 943 A/m2
Figure 7. Variation of (a) thiocyanate concentration and (b) cyanide concentration with and without initial chloride.
Conditions: 943 A/m2
concentrations of SCN, it is imperative that the EO process
operate at lower current density to ensure high current effi-
ciency and overall free CN yield.
Table 3 summarizes the test parameters and the result-
ing current efficiencies.
As shown, there is a significant sensitivity to the process
with changing current density, particularly for actual leach
solutions, which contain additional anions which cause
parasitic reactions to occur on the anode.
CASE STUDY 2: COLD WEATHER MINE
IN ABITIBI REGION
Description of Issue, and Potential for Improvement
As the ore body of the Abitibi Gold Belt example has signif-
icant content of sulfide, the cyanidation process produces
significant concentrations of SCN, which may cause toxic-
ity issues in the receiving environment. Since the site has
a positive water balance, the post detox solution must be
discharged to the environment. To mitigate potential toxic-
ity, the site has a moving bed bioreactor (MBBR) installed
to oxidize the thiospecies to sulphate prior to release to the
environment. While an accepted technology, the MBBR
does contain some inherent downsides, particularly for this
site, namely:
• Cold, northern climate
To ensure sufficient biological activity, the bioreac-
tors and incoming solution needs to be heated, add-
ing significant costs to the treatment.
Figure 6. Variation of (a) thiocyanate concentration and (b) cyanide concentration with and without initial free cyanide.
Conditions: 943 A/m2
Figure 7. Variation of (a) thiocyanate concentration and (b) cyanide concentration with and without initial chloride.
Conditions: 943 A/m2