1360 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
on the surface of the adsorbent. From Figure 9 (c), the zeta
potential value was approximately equal to 0 at pHs lower
than about 8.9, indicating that the adsorption of metal
cations on the surface of the negatively charged adsorbent
led to the neutralization of the adsorbent surface in a wide
range of pHs.
Analysis of Main Effects and Interactions
The effects of the three factors and interactions on the
response (%recovery) for each rare earth elements are dis-
played in Figure 10. In Figure 10a, the plot shows how the
interaction between intensity of mixing and biochar mass
affects the level of recovery of lanthanum. As displayed in
the figure, it is noted that the spread of points on both
sides of the graph are almost equal. At lower intensity
with reduced biochar mass, high recovery of lanthanum
can be achieved, whereas, moving to higher intensity and
high biochar mass will reduce the recovery of lanthanum.
Figure 10b presents one factor plot for the main effect of
intensity on the adsorption of terbium. It is observed from
the plot that the only significant factor is the intensity, and
the figure reveals that low intensity increases the recovery of
terbium while there is a decrease in recovery as the intensity
moves to the higher level. The interaction between intensity
of mixing and biochar mass on the recovery of holmium
is displayed in Figure 10c. It is observed in the graph that
there is a higher spread of points at the right side compared
to the left side. This indicates that the effect of biochar mass
is more significant at any level of intensity, therefore high
recovery of holmium can be achieved by increasing the
biochar mass regardless of the level of intensity. Figure 10d
presents the effects of the interaction between time and
intensity on the recovery of praseodymium. As observed in
the graph, there is little significant effect of the interaction
between time and intensity. However, with high intensity
of mixing, there was a slight increase in recovery as the time
Figure 9. Variation of Zeta potential measurements of all samples at different pH
on the surface of the adsorbent. From Figure 9 (c), the zeta
potential value was approximately equal to 0 at pHs lower
than about 8.9, indicating that the adsorption of metal
cations on the surface of the negatively charged adsorbent
led to the neutralization of the adsorbent surface in a wide
range of pHs.
Analysis of Main Effects and Interactions
The effects of the three factors and interactions on the
response (%recovery) for each rare earth elements are dis-
played in Figure 10. In Figure 10a, the plot shows how the
interaction between intensity of mixing and biochar mass
affects the level of recovery of lanthanum. As displayed in
the figure, it is noted that the spread of points on both
sides of the graph are almost equal. At lower intensity
with reduced biochar mass, high recovery of lanthanum
can be achieved, whereas, moving to higher intensity and
high biochar mass will reduce the recovery of lanthanum.
Figure 10b presents one factor plot for the main effect of
intensity on the adsorption of terbium. It is observed from
the plot that the only significant factor is the intensity, and
the figure reveals that low intensity increases the recovery of
terbium while there is a decrease in recovery as the intensity
moves to the higher level. The interaction between intensity
of mixing and biochar mass on the recovery of holmium
is displayed in Figure 10c. It is observed in the graph that
there is a higher spread of points at the right side compared
to the left side. This indicates that the effect of biochar mass
is more significant at any level of intensity, therefore high
recovery of holmium can be achieved by increasing the
biochar mass regardless of the level of intensity. Figure 10d
presents the effects of the interaction between time and
intensity on the recovery of praseodymium. As observed in
the graph, there is little significant effect of the interaction
between time and intensity. However, with high intensity
of mixing, there was a slight increase in recovery as the time
Figure 9. Variation of Zeta potential measurements of all samples at different pH