3426
Production of High Purity Manganese Sulphate
for the Battery Market
Damian Connelly
Principal Consulting Engineer, METS Engineering Group, Perth
ABSTRACT: The Pilbara region of Western Australia contains significant manganese resources. Historically, some
of these deposits, such as Woodie Woodie for example, have been mined and processed by dense media separation
(DMS) to produce manganese lumps and fines for the steel industry. Some manganese deposits could not be
processed this way owing to high levels of dispersed silica or high levels of iron, hindering their beneficiation.
The development of the lithium-ion battery and the increasing demand for electric vehicles have created a
demand for high purity manganese sulphate. Manganese is a stabilising component in the cathodes of nickel-
manganese-cobalt lithium-ion batteries used in electric vehicles. The material increases energy density and hence
improves driving range. At the same time, it decreases the combustibility of an EV battery pack. This is driving
the increasing demand for high purity (4N) manganese sulphate monohydrate (HPMSM), which is expected
to reach nearly 900% by 2040.
This development has provided an opportunity for exploiting the manganese deposits in the Pilbara that were
otherwise unsuitable for processing by the conventional method. It is particularly suited for producing HPMSM
as it necessitates the use of dilute acid and silica as impurity is not issue as it is not soluble in dilute acid.
Manganese ore is near surface and thus, mining is open cut and low cost. The ore is of medium hardness and
only a relatively coarse grind is required. Thus, the only hurdle is development of an effective processing route
for producing an exceptionally high purity product and little directly relevant information is currently available.
This paper reports the results of an exploratory work to probe the application of various hydrometallurgical
extraction and purifying techniques in the production of HPMSM from a Pilbara ore. These include reductive
leaching of the manganese, low temperature (~100 °C) removal of iron from the PLS as hematite, oxidative
precipitation of the manganese as manganese dioxide from the liquid stream of the iron removal step, to sepa-
rate it from the bulk of the remaining impurities, and re-leaching of the manganese dioxide and purifying the
re-leached manganese by ion exchange (IX) and solvent extraction (SX), The focus of this stage of the work was
to assess the viability of the chosen techniques. Optimisation of the techniques was not attempted and is the
focus of the next stage of the work.
The results show that reductive leaching of the manganese ore in dilute sulfuric acid with sulfur dioxide as
reductant yielded a nearly complete extraction (99%) of the manganese. Low temperature (100 °C) removal of
iron as hematite achieved its almost complete removal together with the aluminium and chromium, with good
solid liquid separation and no co-precipitation of manganese. Oxidative precipitation of manganese to separate
from most impurities yielded nearly 99% manganese dioxide precipitate. Purifying of manganese using IX and
SX yielded a product that appeared to be significantly higher than 99% but not yet 4N. Work is continuing.
Production of High Purity Manganese Sulphate
for the Battery Market
Damian Connelly
Principal Consulting Engineer, METS Engineering Group, Perth
ABSTRACT: The Pilbara region of Western Australia contains significant manganese resources. Historically, some
of these deposits, such as Woodie Woodie for example, have been mined and processed by dense media separation
(DMS) to produce manganese lumps and fines for the steel industry. Some manganese deposits could not be
processed this way owing to high levels of dispersed silica or high levels of iron, hindering their beneficiation.
The development of the lithium-ion battery and the increasing demand for electric vehicles have created a
demand for high purity manganese sulphate. Manganese is a stabilising component in the cathodes of nickel-
manganese-cobalt lithium-ion batteries used in electric vehicles. The material increases energy density and hence
improves driving range. At the same time, it decreases the combustibility of an EV battery pack. This is driving
the increasing demand for high purity (4N) manganese sulphate monohydrate (HPMSM), which is expected
to reach nearly 900% by 2040.
This development has provided an opportunity for exploiting the manganese deposits in the Pilbara that were
otherwise unsuitable for processing by the conventional method. It is particularly suited for producing HPMSM
as it necessitates the use of dilute acid and silica as impurity is not issue as it is not soluble in dilute acid.
Manganese ore is near surface and thus, mining is open cut and low cost. The ore is of medium hardness and
only a relatively coarse grind is required. Thus, the only hurdle is development of an effective processing route
for producing an exceptionally high purity product and little directly relevant information is currently available.
This paper reports the results of an exploratory work to probe the application of various hydrometallurgical
extraction and purifying techniques in the production of HPMSM from a Pilbara ore. These include reductive
leaching of the manganese, low temperature (~100 °C) removal of iron from the PLS as hematite, oxidative
precipitation of the manganese as manganese dioxide from the liquid stream of the iron removal step, to sepa-
rate it from the bulk of the remaining impurities, and re-leaching of the manganese dioxide and purifying the
re-leached manganese by ion exchange (IX) and solvent extraction (SX), The focus of this stage of the work was
to assess the viability of the chosen techniques. Optimisation of the techniques was not attempted and is the
focus of the next stage of the work.
The results show that reductive leaching of the manganese ore in dilute sulfuric acid with sulfur dioxide as
reductant yielded a nearly complete extraction (99%) of the manganese. Low temperature (100 °C) removal of
iron as hematite achieved its almost complete removal together with the aluminium and chromium, with good
solid liquid separation and no co-precipitation of manganese. Oxidative precipitation of manganese to separate
from most impurities yielded nearly 99% manganese dioxide precipitate. Purifying of manganese using IX and
SX yielded a product that appeared to be significantly higher than 99% but not yet 4N. Work is continuing.