3310 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
k2 =The apparent rate constants for internal diffusion
control model
k3 =The apparent rate constants for external diffusion
control model
The analysis of the experimental recoveries using the above
kinetic equations displayed significant and almost linear.
Based on the R2 values, the internal diffusion control model
fitted well for the leaching of Ni using FeCl3, whereas the
interface reaction control model fitted had a good linear
relationship for the leaching of Ni using AC from the
rougher tailings. Similar observations were made recently
by researchers studying the extraction of Mn, Fe, Co, Ni,
and Cu from oceanic cobalt-rich crust (Ju et al. 2024).
These observations indicate that the leaching of Ni using
AC is diffusion controlled on the interface of the tailing
particles (Ju et al. 2024). The highly porous nature of the
AC could also account for this observation. The reaction of
Ni in the ferric chloride medium was predominantly inter-
nal and thus chemically controlled. In that, these elements
were locked in the Fe-Mg silicate matrix, and the lixivi-
ants could only diffuse into the interior of the particles and
encounter them for the sulfation process after the pentland-
ite grains were oxidized.
Consequently, the kinetic models, based on the
Arrhenius plots presented in Figure 9. The analysis of the
data (Eq. 10) revealed apparent activation energies 37.12 kJ/
mol and 26.19 kJ/mol for NiFeCl3 and NiAC respectively.
k =Aexp(− Ea/RT) (10)
where,
k =The apparent rate constant (h−1)
A =The pre-exponential factor (h−1)
Ea =The activation energy (J/mol)
R =The molar gas constant (8.314 J/(mol·k))
T =The thermodynamic temperature (K)
CONCLUSIONS
In the present study, the leaching of rougher tailings using
the activated carbon and sulfuric acid system is examined,
and a simple, effective, and environmentally friendly tech-
nique for recovering the valuable metal resources present
in the tailings is established. The results showed that the
leaching time, temperature, and the catalyst concentra-
tion had significant effects on the leaching recoveries. The
catalyst type had minimal influence, and due to the reus-
ability, environmental friendliness of activated carbon and
its feasibility of practical operation, the AC-H2SO4 system
was proposed. The response surface methodology was used
to study the effects of the various conditions on the leach-
ing recovery and optimize the experimental parameter. The
quadratic regression model has a high reliability, as demon-
strated by the verification experiments and F and p-value
tests (p 0.05) of the model, which optimizes the process
parameters in the leaching process. The optimal results show
that 97.95% Ni was recovered using H2SO4 concentration
of 1 M, AC addition of 30 g/L, and leaching temperature
of 80 °C for 24 h. The kinetic analysis demonstrates that
the leaching process with the activated carbon-sulfuric acid
-6.5
-6
-5.5
-5
-4.5
-4
0.0028 0.0029 0.003 0.0031 0.0032 0.0033 0.0034
1/T (K-1)
The apparent activation energy
(Ni
FeCl3 ):37.12 kJ/mol
-6
-5.5
-5
-4.5
-4
0.0028 0.0029 0.003 0.0031 0.0032 0.0033 0.0034
1/T (K-1)
The apparent activation energy (Ni
AC
):26.19 kJ/mol
Figure 9. The Arrhenius plots for the leaching of (a) Ni using FeCl
3 ,and (b) Ni using AC
In
K 2
In
K 1
k2 =The apparent rate constants for internal diffusion
control model
k3 =The apparent rate constants for external diffusion
control model
The analysis of the experimental recoveries using the above
kinetic equations displayed significant and almost linear.
Based on the R2 values, the internal diffusion control model
fitted well for the leaching of Ni using FeCl3, whereas the
interface reaction control model fitted had a good linear
relationship for the leaching of Ni using AC from the
rougher tailings. Similar observations were made recently
by researchers studying the extraction of Mn, Fe, Co, Ni,
and Cu from oceanic cobalt-rich crust (Ju et al. 2024).
These observations indicate that the leaching of Ni using
AC is diffusion controlled on the interface of the tailing
particles (Ju et al. 2024). The highly porous nature of the
AC could also account for this observation. The reaction of
Ni in the ferric chloride medium was predominantly inter-
nal and thus chemically controlled. In that, these elements
were locked in the Fe-Mg silicate matrix, and the lixivi-
ants could only diffuse into the interior of the particles and
encounter them for the sulfation process after the pentland-
ite grains were oxidized.
Consequently, the kinetic models, based on the
Arrhenius plots presented in Figure 9. The analysis of the
data (Eq. 10) revealed apparent activation energies 37.12 kJ/
mol and 26.19 kJ/mol for NiFeCl3 and NiAC respectively.
k =Aexp(− Ea/RT) (10)
where,
k =The apparent rate constant (h−1)
A =The pre-exponential factor (h−1)
Ea =The activation energy (J/mol)
R =The molar gas constant (8.314 J/(mol·k))
T =The thermodynamic temperature (K)
CONCLUSIONS
In the present study, the leaching of rougher tailings using
the activated carbon and sulfuric acid system is examined,
and a simple, effective, and environmentally friendly tech-
nique for recovering the valuable metal resources present
in the tailings is established. The results showed that the
leaching time, temperature, and the catalyst concentra-
tion had significant effects on the leaching recoveries. The
catalyst type had minimal influence, and due to the reus-
ability, environmental friendliness of activated carbon and
its feasibility of practical operation, the AC-H2SO4 system
was proposed. The response surface methodology was used
to study the effects of the various conditions on the leach-
ing recovery and optimize the experimental parameter. The
quadratic regression model has a high reliability, as demon-
strated by the verification experiments and F and p-value
tests (p 0.05) of the model, which optimizes the process
parameters in the leaching process. The optimal results show
that 97.95% Ni was recovered using H2SO4 concentration
of 1 M, AC addition of 30 g/L, and leaching temperature
of 80 °C for 24 h. The kinetic analysis demonstrates that
the leaching process with the activated carbon-sulfuric acid
-6.5
-6
-5.5
-5
-4.5
-4
0.0028 0.0029 0.003 0.0031 0.0032 0.0033 0.0034
1/T (K-1)
The apparent activation energy
(Ni
FeCl3 ):37.12 kJ/mol
-6
-5.5
-5
-4.5
-4
0.0028 0.0029 0.003 0.0031 0.0032 0.0033 0.0034
1/T (K-1)
The apparent activation energy (Ni
AC
):26.19 kJ/mol
Figure 9. The Arrhenius plots for the leaching of (a) Ni using FeCl
3 ,and (b) Ni using AC
In
K 2
In
K 1