3395
Flowsheet Options for the Hydrometallurgical Production of
Battery-Grade Manganese Salts
Benjamin D.H. Knights, Jasper J.C. Christie Given Khosa, Nakiwe S. Dlamini, Collins T. Saguru
CM Solutions, South Africa
ABSTRACT: Unprecedented interest in the energy sector has led to rapidly changing requirements for battery
chemistries. An element with increased interest is manganese. Hydrometallurgical processing of manganese
feedstock has historically not been economically viable. However, as an energy mineral there is now a premium
on high-purity manganese products. There are several hydrometallurgical challenges in generating battery-grade
manganese. This includes the use of low redox leaching and purification steps to remove Ca, Mg, Na, Si and K.
The final product could include manganese metal, manganese dioxide or manganese salts. This paper provides a
high-level overview of possible flowsheets, as well as options and technologies for the flowsheet.
INTRODUCTION
Approximately 81% of Mn produced globally in 2018 was
from just 6 countries, with South Africa contributing the
most at close to 31% to global supply (Mineral Commodity
Summaries, 2021). More than 90% of the globally pro-
duced Mn has traditionally been processed pyrometallur-
gically for the steel industry, with the remainder finding
niche applications in non-ferrous alloying and within the
chemical industry. Mn is used for both refining iron ore as
a de-oxidizer and for alloying steel to reduce brittleness and
increase tensile strength.
Mn is the 12th most abundant element in the earth’s
crust (Steenkamp and Basson, 2012), and is known to
occur in 3 types of deposit: sedimentary, hydrothermal and
superficial (Roy, 1968). South Africa accounts for 40% of
the global Mn reserves (Mineral Commodity Summaries,
2021). The majority of the South African deposit is in
the Kalahari basin, in the Northern Cape province. This
deposit is hydrothermal in nature. Manganese mineral-
ogy can be extremely complex, with significant mineral
species intergrowth, as well as manganese displacement of
other elements in various minerals. For example Jacobsite
(Fe2MnO4), which forms a solid solution series with mag-
netite. Pyrolusite (MnO2) often occurs as an intergrowth
with other manganese oxides, silicates and carbonates.
Mn is finding new applications in emerging use cases.
Worldwide calls for environmentally sustainable energy
generation and storage have resulted in increased atten-
tion by policy makers, the scientific community and busi-
ness leaders on renewable energy generation and storage
technologies. The battery storage market has consequently
grown, primarily driven by the growth of the electric
vehicle (EV) market. Mn is used in the manufacture of
cathodes for Li-ion batteries to improve cell energy den-
sity. Substitution of metals like Co in the cathode struc-
ture also significantly reduces the cost of production (Yi
et al., 2023). The demand for high purity MnO2 and/or
High Purity Manganese Sulfate Monohydrate (HPMSM)
for battery manufacture is therefore expected to grow as
the demand for batteries utilizing Mn based chemistries
increases as well.
These emerging demand drivers have ignited interest
within the metallurgical industry for a hydrometallurgi-
cal process to recover battery grade manganese products.
Flowsheet Options for the Hydrometallurgical Production of
Battery-Grade Manganese Salts
Benjamin D.H. Knights, Jasper J.C. Christie Given Khosa, Nakiwe S. Dlamini, Collins T. Saguru
CM Solutions, South Africa
ABSTRACT: Unprecedented interest in the energy sector has led to rapidly changing requirements for battery
chemistries. An element with increased interest is manganese. Hydrometallurgical processing of manganese
feedstock has historically not been economically viable. However, as an energy mineral there is now a premium
on high-purity manganese products. There are several hydrometallurgical challenges in generating battery-grade
manganese. This includes the use of low redox leaching and purification steps to remove Ca, Mg, Na, Si and K.
The final product could include manganese metal, manganese dioxide or manganese salts. This paper provides a
high-level overview of possible flowsheets, as well as options and technologies for the flowsheet.
INTRODUCTION
Approximately 81% of Mn produced globally in 2018 was
from just 6 countries, with South Africa contributing the
most at close to 31% to global supply (Mineral Commodity
Summaries, 2021). More than 90% of the globally pro-
duced Mn has traditionally been processed pyrometallur-
gically for the steel industry, with the remainder finding
niche applications in non-ferrous alloying and within the
chemical industry. Mn is used for both refining iron ore as
a de-oxidizer and for alloying steel to reduce brittleness and
increase tensile strength.
Mn is the 12th most abundant element in the earth’s
crust (Steenkamp and Basson, 2012), and is known to
occur in 3 types of deposit: sedimentary, hydrothermal and
superficial (Roy, 1968). South Africa accounts for 40% of
the global Mn reserves (Mineral Commodity Summaries,
2021). The majority of the South African deposit is in
the Kalahari basin, in the Northern Cape province. This
deposit is hydrothermal in nature. Manganese mineral-
ogy can be extremely complex, with significant mineral
species intergrowth, as well as manganese displacement of
other elements in various minerals. For example Jacobsite
(Fe2MnO4), which forms a solid solution series with mag-
netite. Pyrolusite (MnO2) often occurs as an intergrowth
with other manganese oxides, silicates and carbonates.
Mn is finding new applications in emerging use cases.
Worldwide calls for environmentally sustainable energy
generation and storage have resulted in increased atten-
tion by policy makers, the scientific community and busi-
ness leaders on renewable energy generation and storage
technologies. The battery storage market has consequently
grown, primarily driven by the growth of the electric
vehicle (EV) market. Mn is used in the manufacture of
cathodes for Li-ion batteries to improve cell energy den-
sity. Substitution of metals like Co in the cathode struc-
ture also significantly reduces the cost of production (Yi
et al., 2023). The demand for high purity MnO2 and/or
High Purity Manganese Sulfate Monohydrate (HPMSM)
for battery manufacture is therefore expected to grow as
the demand for batteries utilizing Mn based chemistries
increases as well.
These emerging demand drivers have ignited interest
within the metallurgical industry for a hydrometallurgi-
cal process to recover battery grade manganese products.