XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1897
(ClO–) to chlorate (ClO3–) ions at higher temperatures
(Eq 8 and Eq 9) (Hesami et al., 2022).
3 2Cl ClO ClO
3 )+---(8)
2 2Cl ClO O
2 )+--(9)
An increase in particle size resulted in a decrease in
arsenic dissolution. Increasing the particle size decreases the
surface area which leads to lesser available sites for leaching
to occur. This observation conforms with the study of Viñals
et al. (2003). However, it should be noted that obtaining
a P80 of 37 µm already requires fine grinding. This type
of grinding is energy intensive and entails higher grinding
media costs. Furthermore, fine grinding usually corresponds
to using a stirred mill and may not be easily achieved using
the typical ball or SAG mills (de Bakker 2014).
NaClO-NaOH Leaching Kinetics
The As dissolution in NaClO-NaOH system at varying
temperatures, fixed NaClO concentration and particle size
is presented in Figure 5. The leaching curve is character-
ized by a fast initial dissolution rate followed by a dras-
tic decrease. Arsenic dissolution is higher at 45°C than at
30°C. Furthermore, dissolution is lower at 60°C than at
Figure 4. Main effects plot for arsenic dissolution via NaClO-NaOH leaching
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 20 40 60 80 100 120
Time, mins
30C 45C 60C
Figure 5. Arsenic dissolution in NaClO-NaOH leaching with varying temperatures at fixed
NaClO concentration (0.6M) and P80 of 37 um
As
Dissolution ,
%
(ClO–) to chlorate (ClO3–) ions at higher temperatures
(Eq 8 and Eq 9) (Hesami et al., 2022).
3 2Cl ClO ClO
3 )+---(8)
2 2Cl ClO O
2 )+--(9)
An increase in particle size resulted in a decrease in
arsenic dissolution. Increasing the particle size decreases the
surface area which leads to lesser available sites for leaching
to occur. This observation conforms with the study of Viñals
et al. (2003). However, it should be noted that obtaining
a P80 of 37 µm already requires fine grinding. This type
of grinding is energy intensive and entails higher grinding
media costs. Furthermore, fine grinding usually corresponds
to using a stirred mill and may not be easily achieved using
the typical ball or SAG mills (de Bakker 2014).
NaClO-NaOH Leaching Kinetics
The As dissolution in NaClO-NaOH system at varying
temperatures, fixed NaClO concentration and particle size
is presented in Figure 5. The leaching curve is character-
ized by a fast initial dissolution rate followed by a dras-
tic decrease. Arsenic dissolution is higher at 45°C than at
30°C. Furthermore, dissolution is lower at 60°C than at
Figure 4. Main effects plot for arsenic dissolution via NaClO-NaOH leaching
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 20 40 60 80 100 120
Time, mins
30C 45C 60C
Figure 5. Arsenic dissolution in NaClO-NaOH leaching with varying temperatures at fixed
NaClO concentration (0.6M) and P80 of 37 um
As
Dissolution ,
%