XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3403
number of different methods, including sulfidation (Kim
and Tran, 2015), solvent extraction or ion exchange (dis-
cussed previously).
Ca and Mg Removal
Ca and Mg are present either from reagent addition in
prior processing steps, or from gangue leaching. Removal
of these elements can be accomplished by fluoride precipi-
tation polishing, as described by (Geldenhuys, 2023) for
the K Hill project flowsheet. Hydrofluoric acid is added
as a source of fluoride ions, and Ba(OH)2 is used for pH
modification. (Geldenhuys, 2023) reported that Ca is
completely removed whilst a significant (but unspecified)
amount of Mg is also precipitated. It was also reported that
residual fluoride could then be removed by adsorption onto
alumina.
(Kim and Tran, 2015) approached Ca removal in a
different way, by subjecting the Mn ore to a dilute HCl
leach, prior to reductive sulfuric acid leaching. The authors
reported that the Ca in chloride leach solution could be
subjected to sulfite precipitation, followed by calcining to
obtain CaO and SO2 which would be used during the sub-
sequent reductive sulfuric acid leach. The introduction of
chloride ions, however, could increase capital and operating
expenditure, when considering the materials of construc-
tion and effluent handling requirements.
(Lin et al., 2016) also studied a carbonate precipita-
tion route for separation of Mn from 1.89 g/L Mg and
1.54 g/L Ca solution in acidic sulfate media. NH4HCO3
was used to precipitate Mn, and reject the Ca and Mg. The
precipitation extents attained were 99.75% Mn, 5.62% Ca
and 1.43% Mg under optimized conditions. It should be
noted that the Mn tenor employed in the study, of about
14.59 g/L, is significantly less than the typical Mn tenors
which are usually in the range of 80–110 g/L. The authors
also observed that addition of Mn PLS to NH4HCO3
(instead of NH4HCO3 to PLS) seemed to offer improved
rejection of Ca and Mg as evidenced by the Ca and Mg
contents in the precipitates as presented in Table 3. The
impure Mn carbonate could then be re-dissolved prior to
removal of the Ca and Mg using other technologies like ion
exchange.
CONCLUSION
The hydrometallurgical production of battery grade man-
ganese salts presents several challenges. Highly variable
feedstock, low tolerance for impurities and complex chem-
istry presents a number of challenges for effective flowsheet
development. Nonetheless this also presents the industry
with opportunities for innovation and the novel pivoting of
existing technologies to this new application.
REFERENCES
Acharya, R., Ghosh, M.K., Anand, S., Das, R.P.,
1999. Leaching of metals from Indian ocean nod-
ules in SO2–H2O–H2SO4–(NH4)2SO4 medium.
Hydrometallurgy 53, 169–175. doi: 10.1016
/S0304-386X(99)00040-7.
Bafghi, M.Sh., Zakeri, A., Ghasemi, Z., Adeli, M., 2008.
Reductive dissolution of manganese ore in sulfuric acid
in the presence of iron metal. Hydrometallurgy 90,
207–212. doi: 10.1016/j.hydromet.2007.07.003.
Cheng, C.Y., 2000. Purification of synthetic laterite
leach solution by solvent extraction using D2EHPA.
Hydrometallurgy 56, 369–386. doi: 10.1016
/S0304-386X(00)00095-5.
Cheng, Z., Zhu, G., Zhao, Y., 2009. Study in reduc-
tion-roast leaching manganese from low-grade
manganese dioxide ores using cornstalk as reduc-
tant. Hydrometallurgy 96, 176–179. doi: 10.1016
/j.hydromet.2008.08.004.
Das, G.K., Anand, S., Das, R.P., Muir, D., Singh, P., 2000.
Sulfur Dioxide – A Leachant for Oxidic Materials in
Aqueous and Non-aqueous Media. Miner. Process.
Extr. Metall. Rev. 20, 377–407. doi: 10.1080
/08827509908962483.
Deng, L., Qu, B., Su, S.-J., Ding, S.-L., Sun, W.-Y., 2017.
Study on Separation of Manganese from Iron in High-
Iron Pyrolusite Ore by Leaching with Simulated Flue
Gas. J. Chem. Eng. Jpn. 50, 892–899. doi: 10.1252/
jcej.16we377.
Falco, L., Quina, M.J., Gando-Ferreira, L.M., Thomas, H.,
Curutchet, G., 2014. Solvent Extraction Studies for
Separation of Zn(II) and Mn(II) from Spent Batteries
Leach Solutions. Sep. Sci. Technol. 49, 398–409. doi:
10.1080/01496395.2013.850510.
Table 3. Ca and Mg content in Mn carbonate precipitation
product
Reagent Addition Method
Metal content in product
(mass fraction) %
Ca Mg
Adding MnSO4 solution to
NH4HCO3 solution
0.30 0.10
Adding NH
4 HCO
3 solution to
MnSO
4 solution
1.17 0.68
Simultaneous feeding of reagents 1.08 0.73
number of different methods, including sulfidation (Kim
and Tran, 2015), solvent extraction or ion exchange (dis-
cussed previously).
Ca and Mg Removal
Ca and Mg are present either from reagent addition in
prior processing steps, or from gangue leaching. Removal
of these elements can be accomplished by fluoride precipi-
tation polishing, as described by (Geldenhuys, 2023) for
the K Hill project flowsheet. Hydrofluoric acid is added
as a source of fluoride ions, and Ba(OH)2 is used for pH
modification. (Geldenhuys, 2023) reported that Ca is
completely removed whilst a significant (but unspecified)
amount of Mg is also precipitated. It was also reported that
residual fluoride could then be removed by adsorption onto
alumina.
(Kim and Tran, 2015) approached Ca removal in a
different way, by subjecting the Mn ore to a dilute HCl
leach, prior to reductive sulfuric acid leaching. The authors
reported that the Ca in chloride leach solution could be
subjected to sulfite precipitation, followed by calcining to
obtain CaO and SO2 which would be used during the sub-
sequent reductive sulfuric acid leach. The introduction of
chloride ions, however, could increase capital and operating
expenditure, when considering the materials of construc-
tion and effluent handling requirements.
(Lin et al., 2016) also studied a carbonate precipita-
tion route for separation of Mn from 1.89 g/L Mg and
1.54 g/L Ca solution in acidic sulfate media. NH4HCO3
was used to precipitate Mn, and reject the Ca and Mg. The
precipitation extents attained were 99.75% Mn, 5.62% Ca
and 1.43% Mg under optimized conditions. It should be
noted that the Mn tenor employed in the study, of about
14.59 g/L, is significantly less than the typical Mn tenors
which are usually in the range of 80–110 g/L. The authors
also observed that addition of Mn PLS to NH4HCO3
(instead of NH4HCO3 to PLS) seemed to offer improved
rejection of Ca and Mg as evidenced by the Ca and Mg
contents in the precipitates as presented in Table 3. The
impure Mn carbonate could then be re-dissolved prior to
removal of the Ca and Mg using other technologies like ion
exchange.
CONCLUSION
The hydrometallurgical production of battery grade man-
ganese salts presents several challenges. Highly variable
feedstock, low tolerance for impurities and complex chem-
istry presents a number of challenges for effective flowsheet
development. Nonetheless this also presents the industry
with opportunities for innovation and the novel pivoting of
existing technologies to this new application.
REFERENCES
Acharya, R., Ghosh, M.K., Anand, S., Das, R.P.,
1999. Leaching of metals from Indian ocean nod-
ules in SO2–H2O–H2SO4–(NH4)2SO4 medium.
Hydrometallurgy 53, 169–175. doi: 10.1016
/S0304-386X(99)00040-7.
Bafghi, M.Sh., Zakeri, A., Ghasemi, Z., Adeli, M., 2008.
Reductive dissolution of manganese ore in sulfuric acid
in the presence of iron metal. Hydrometallurgy 90,
207–212. doi: 10.1016/j.hydromet.2007.07.003.
Cheng, C.Y., 2000. Purification of synthetic laterite
leach solution by solvent extraction using D2EHPA.
Hydrometallurgy 56, 369–386. doi: 10.1016
/S0304-386X(00)00095-5.
Cheng, Z., Zhu, G., Zhao, Y., 2009. Study in reduc-
tion-roast leaching manganese from low-grade
manganese dioxide ores using cornstalk as reduc-
tant. Hydrometallurgy 96, 176–179. doi: 10.1016
/j.hydromet.2008.08.004.
Das, G.K., Anand, S., Das, R.P., Muir, D., Singh, P., 2000.
Sulfur Dioxide – A Leachant for Oxidic Materials in
Aqueous and Non-aqueous Media. Miner. Process.
Extr. Metall. Rev. 20, 377–407. doi: 10.1080
/08827509908962483.
Deng, L., Qu, B., Su, S.-J., Ding, S.-L., Sun, W.-Y., 2017.
Study on Separation of Manganese from Iron in High-
Iron Pyrolusite Ore by Leaching with Simulated Flue
Gas. J. Chem. Eng. Jpn. 50, 892–899. doi: 10.1252/
jcej.16we377.
Falco, L., Quina, M.J., Gando-Ferreira, L.M., Thomas, H.,
Curutchet, G., 2014. Solvent Extraction Studies for
Separation of Zn(II) and Mn(II) from Spent Batteries
Leach Solutions. Sep. Sci. Technol. 49, 398–409. doi:
10.1080/01496395.2013.850510.
Table 3. Ca and Mg content in Mn carbonate precipitation
product
Reagent Addition Method
Metal content in product
(mass fraction) %
Ca Mg
Adding MnSO4 solution to
NH4HCO3 solution
0.30 0.10
Adding NH
4 HCO
3 solution to
MnSO
4 solution
1.17 0.68
Simultaneous feeding of reagents 1.08 0.73