3419
Production of Battery Grade Manganese Sulfate Monohydrate
from High Carbon-Ferromanganese Smelter Waste Streams
N.D. Ilankoon, E.A. Oraby, L. Hockaday, J.J. Eksteen
Western Australian School of Mines: Minerals, Energy &Chemical Engineering, Curtin University, Australia
ABSTRACT: Manganese, which is considered as a critical metal, has many uses mainly in steel industry as an
alloying agent and in battery industry as a cathode material for rechargeable electric vehicle battery production
as well as in single use non-rechargeable batteries. The projected demand and interest for high purity manganese
sulfate monohydrate (HPMSM) and electrolytic manganese metal (EMM) are increasing rapidly. The production
of these products requires stringent purification of leach solutions to meet the industry specifications of the
final product. High carbon ferromanganese process produces two main waste streams, a slag and Mn mud
derived from recovered furnace dust. In this study, Mn mud waste stream was used for the recovery of Mn by
acid leaching followed by leach solution purification and HPMSM crystallisation. In contrast to conventional
manganese ores where manganese often occurs in tetravalent or trivalent states, manganese from these waste
resources is already in a reduced (divalent) state, alleviating the need for a reducing leach. The Mn mud waste
contained approximately 42% of Mn. Direct acid leaching was used for mud. The pregnant leach solutions
(PLS) consisted of 85 g/L of Mn with Al, Ca, Fe, Na, K, Mg, Si and Zn as major impurities after leaching
at room temperature for 2 hours. Based on the test outcomes, approximately 85% of Mn was recovered by
leaching Mn mud. Precipitation and solvent extraction were used for PLS purification. Manganese sulfate was
produced by evaporative crystallisation. According to preliminary experiments, the production of HPMSM by
using ferromanganese smelter waste streams is technically feasible.
INTRODUCTION
Manganese mainly occurs in nature as oxide, carbonate and
silicate whereas oxides are more prevalent and carbonates
are relatively somewhat rare. Manganese carbonate is read-
ily soluble in sulfuric acid whilst the oxide ores are insol-
uble without a reducing environment. Oxide ores require
a calcination step prior to leaching, or reductive leaching
medium to make it soluble in sulfuric acid (Momade,
1996, Winjobi and Kelly, 2021). Manganese is the fourth
mined element in the world after iron, aluminium, and
copper, in tonnage (Jephcott, 2023). According to pub-
lished work, in 2021, South Africa was the top producer
of Mn followed by Gabon, Australia and China (Jephcott,
2023). Approximately 90% of the Mn is utilised to produce
ferromanganese and silicomanganese for steel production
whilst the remaining 10% is used for manganese salts and
electrolytic manganese products. Among these products,
the high pure electrolytic manganese metal (HPEMM) and
high pure manganese sulfate monohydrate (HPMSM) are
mainly used in lithium ion battery (LIB) industry.
Manganese sulfate monohydrate is a light pink pow-
der with the formula MnSO4·H2O. Commercially two
main methods are used for HPMSM production. The most
common and widely used method is the use of manganese
ore. Alternatively, HPEMM is used as the raw material for
Production of Battery Grade Manganese Sulfate Monohydrate
from High Carbon-Ferromanganese Smelter Waste Streams
N.D. Ilankoon, E.A. Oraby, L. Hockaday, J.J. Eksteen
Western Australian School of Mines: Minerals, Energy &Chemical Engineering, Curtin University, Australia
ABSTRACT: Manganese, which is considered as a critical metal, has many uses mainly in steel industry as an
alloying agent and in battery industry as a cathode material for rechargeable electric vehicle battery production
as well as in single use non-rechargeable batteries. The projected demand and interest for high purity manganese
sulfate monohydrate (HPMSM) and electrolytic manganese metal (EMM) are increasing rapidly. The production
of these products requires stringent purification of leach solutions to meet the industry specifications of the
final product. High carbon ferromanganese process produces two main waste streams, a slag and Mn mud
derived from recovered furnace dust. In this study, Mn mud waste stream was used for the recovery of Mn by
acid leaching followed by leach solution purification and HPMSM crystallisation. In contrast to conventional
manganese ores where manganese often occurs in tetravalent or trivalent states, manganese from these waste
resources is already in a reduced (divalent) state, alleviating the need for a reducing leach. The Mn mud waste
contained approximately 42% of Mn. Direct acid leaching was used for mud. The pregnant leach solutions
(PLS) consisted of 85 g/L of Mn with Al, Ca, Fe, Na, K, Mg, Si and Zn as major impurities after leaching
at room temperature for 2 hours. Based on the test outcomes, approximately 85% of Mn was recovered by
leaching Mn mud. Precipitation and solvent extraction were used for PLS purification. Manganese sulfate was
produced by evaporative crystallisation. According to preliminary experiments, the production of HPMSM by
using ferromanganese smelter waste streams is technically feasible.
INTRODUCTION
Manganese mainly occurs in nature as oxide, carbonate and
silicate whereas oxides are more prevalent and carbonates
are relatively somewhat rare. Manganese carbonate is read-
ily soluble in sulfuric acid whilst the oxide ores are insol-
uble without a reducing environment. Oxide ores require
a calcination step prior to leaching, or reductive leaching
medium to make it soluble in sulfuric acid (Momade,
1996, Winjobi and Kelly, 2021). Manganese is the fourth
mined element in the world after iron, aluminium, and
copper, in tonnage (Jephcott, 2023). According to pub-
lished work, in 2021, South Africa was the top producer
of Mn followed by Gabon, Australia and China (Jephcott,
2023). Approximately 90% of the Mn is utilised to produce
ferromanganese and silicomanganese for steel production
whilst the remaining 10% is used for manganese salts and
electrolytic manganese products. Among these products,
the high pure electrolytic manganese metal (HPEMM) and
high pure manganese sulfate monohydrate (HPMSM) are
mainly used in lithium ion battery (LIB) industry.
Manganese sulfate monohydrate is a light pink pow-
der with the formula MnSO4·H2O. Commercially two
main methods are used for HPMSM production. The most
common and widely used method is the use of manganese
ore. Alternatively, HPEMM is used as the raw material for