XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1727
at circumneutral pH, providing a chemical-less extraction
process for these elements from AMD.
Effect of Process Parameters
The effect of individual parameters such as stirring rate,
flow rate, and temperature on the oxidative precipitation of
ozone was studied to maximize the recovery of the Co-Mn
from AMD.
Gas Flow Rate
The gas flow rate (oxygen flow rate) is one of the signifi-
cant parameters affecting the oxidative precipitation of Co
and Mn using ozone (Tian et al., 2017). The effect of this
parameter on the recovery of Co and Mn from the AMD
as a function of time was studied at room temperature
(25°C), neutral solution pH, and stirring speed of 400 rpm
(Figure 4). The results of the first five minutes showed that
by increasing the gas flow rate from 200 cc/min to 2000
cc/min, the Co precipitation was first increased, possibly
due to the increased availability of ozone for the reaction,
and then decreased, possibly due to the reduction in the
residence time for the conversion of oxygen to ozone.
However, based on 95% CI, the Mn precipitation was not
significantly changed as the Oxidation-Reduction Potential
(ORP) of the system was likely still within the level that can
provide fast Mn oxidation.
Effect of Stirring Speed
The stirring rate affects the mass transfer of ozone through
the mixing of the reaction system, thereby impacting the
ozone oxidative precipitation process (Tian et al., 2017).
Thereby, the effect of the stirring rate on the precipitation
of Co and Mn using ozone was studied at room tempera-
ture (25 °C), neutral solution pH, and a low gas rate of
250 cc/min (Figure 5). It was found that increasing stirring
speed from 0 to 1500 rpm significantly improves the pre-
cipitation of Co-Mn in the first five minutes. However, the
increase was not significantly different from 0 to 1200 rpm
Figure 4. Co-Mn recovery values as a function of time at different gas flow rates
Figure 5. Co-Mn recovery values as a function of time at different stirring rate
at circumneutral pH, providing a chemical-less extraction
process for these elements from AMD.
Effect of Process Parameters
The effect of individual parameters such as stirring rate,
flow rate, and temperature on the oxidative precipitation of
ozone was studied to maximize the recovery of the Co-Mn
from AMD.
Gas Flow Rate
The gas flow rate (oxygen flow rate) is one of the signifi-
cant parameters affecting the oxidative precipitation of Co
and Mn using ozone (Tian et al., 2017). The effect of this
parameter on the recovery of Co and Mn from the AMD
as a function of time was studied at room temperature
(25°C), neutral solution pH, and stirring speed of 400 rpm
(Figure 4). The results of the first five minutes showed that
by increasing the gas flow rate from 200 cc/min to 2000
cc/min, the Co precipitation was first increased, possibly
due to the increased availability of ozone for the reaction,
and then decreased, possibly due to the reduction in the
residence time for the conversion of oxygen to ozone.
However, based on 95% CI, the Mn precipitation was not
significantly changed as the Oxidation-Reduction Potential
(ORP) of the system was likely still within the level that can
provide fast Mn oxidation.
Effect of Stirring Speed
The stirring rate affects the mass transfer of ozone through
the mixing of the reaction system, thereby impacting the
ozone oxidative precipitation process (Tian et al., 2017).
Thereby, the effect of the stirring rate on the precipitation
of Co and Mn using ozone was studied at room tempera-
ture (25 °C), neutral solution pH, and a low gas rate of
250 cc/min (Figure 5). It was found that increasing stirring
speed from 0 to 1500 rpm significantly improves the pre-
cipitation of Co-Mn in the first five minutes. However, the
increase was not significantly different from 0 to 1200 rpm
Figure 4. Co-Mn recovery values as a function of time at different gas flow rates
Figure 5. Co-Mn recovery values as a function of time at different stirring rate