FACT SHEET 10
International Manganese Institute
Electrolytic Manganese Dioxide
(EMD) and Pyrolusite ore:
What’s the Difference?
This fact sheet outlines the intrinsic properties of natural
manganese dioxide ore - pyrolusite, and the chemically
manufactured manganese dioxide, Electrolytic Manganese
Dioxide (EMD). Both are termed manganese dioxide,
yet their properties differ. This is important to highlight as
workplace safety measures should also differ and regulatory
frameworks should consider these differences.
1.Introduction
High grade Pyrolusite contains approximately 40% by weight of
manganese dioxide (MnO2) with the remaining 60% composed
of other metallic substances in their oxide forms. Once mined,
the ore is beneficiated and/or sintered before being used in
the production of alloys. Meanwhile, Electrolytic Manganese
Dioxide (EMD) contains greater than 95% by weight of MnO2
with only some very minor impurities making up the remaining
<5%. It is mostly in the production of batteries. Figure 1 shows
EMD and Pyrolusite, the two forms of MnO2.
2. Mineralogical Comparison
A comparison between the mineralogy of Pyrolusite and the
chemically manufactured EMD can be undertaken using X-ray
diffraction. This method is used to identify the atomic and
molecular structure of crystals that are bombarded with X-rays.
The diffraction pattern of these X-rays by the crystal, shown as
peaks on traces, gives an indication of the physical structure
and so potential physical properties.
Figure 2 shows two X-ray diffraction spectra, the top one
for EMD and the bottom for pyrolusite. The key differences
between the traces are that Pyrolusite has many peaks
that are broad at the base indicating a high level of disorder
in the structure and a lack of crystallinity. The EMD trace is
very different with sharp, narrow peaks that indicate clear
crystallinity of structure. Pyrolusite is an array of interlocking
mineral structures, predominantly Pyrolusite but also small
quantities of manganosite, hollandite, hematite to name but
a few, hence its regulatory profile as a UVCB (Unknown or
Variable composition, Complex reaction products or biological
Materials) substance. Meanwhile, EMD does not contain
such variation of interwoven mineral layers but a clear
crystalline structure made up predominantly of MnO2, and
so is referred to within the regulatory frame work as a
monoconstituent substance.
MnO2 (A212-02792)
a)
Lin (Counts)
300000
200000
100000
0
11
20
30
40
50
60
70
80
60
70
80
2-Theta - Scale
33000
32000
Mn ore (A212-02964)
MnO2Bernd - File: MnO2bernd.raw - Type: 2Th/Th locked - Start: 10.000 ° - End: 80.114 ° - Step: 0.058 ° - Step time: 573. s - Divergence slit: 0.499 °
Operations: Strip kAlpha2 0.500 | Background 1.000,1.000 | Import
01-071-0071 (*) - Pyrolusite, syn - MnO2 -
31000
30000
29000
28000
27000
b)
26000
25000
24000
23000
22000
21000
Lin (Counts)
20000
19000
18000
17000
16000
15000
14000
13000
12000
11000
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
11
20
30
40
50
2-Theta - Scale
2 Theta
scale
2 Theta scale
A212-02964 - File: A212-02964.raw - Type: 2Th/Th locked - Start: 10.000 ° - End: 80.114 ° - Step: 0.058 °
Operations: Background 0.977,1.000 | Import
00-050-0016 (N) - Nickel Manganese Oxide Hydrate - Ni2Mn14O27·xH2O - S-Q 51.5 %
00-026-1076 (C) - Carbon - C - S-Q 16.2 %
00-042-1319 (N) - Asbolane - NiMn2O3(OH)4·H2O - S-Q 10.2 %
00-046-0607 (I) - Lithium Aluminum Silicate - Li5AlSi2O8 - S-Q 8.3 %
00-041-1378 (*) - Lithiophorite - (Al,Li)Mn+4O2(OH)2 - S-Q 7.7 %
00-029-0349 (C) - Calcium Manganese Oxide - Ca2Mn8O16 - S-Q 5.4 %
00-043-1456 (*) - Birnessite, syn - Na0.55Mn2O4·1.5H2O - S-Q 0.7 %
Figure 2. X-ray diffraction traces for EMD (top) and Pyrolusite (bottom).
Figure 1. Electrolytic Manganese Dioxide (EMD) (a) and pyrolusite (b).
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FACT SHEET 10
International Manganese Institute
3. Physico-chemical comparison
The hazard properties of Pyrolusite and EMD were tested
according to thC United Nations Recommendations on
the Transport of Dangerous Goods Manual of Tests and
Criteria; EU REACH Regulation (EC) No 1272/2008,
Classification Labelling and Packaging of Substances and
Mixtures (CLP); and the Global Harmonised System of
classification and Labelling (GHS). The results from these
tests, shown in Table 1, indicate that both substances do not
pose a physicochemical hazard.
Table 1. Comparison of some of the regulatory relevant properties of
Pyrolusite and EMD
Studies
Pyrolusite Ore
EMD
Result
Result
Not flammable
Not flammable
Not classified as self
heating
Not classified as
self heating
Explosive Properties
Predicted negative
based on structure
Predicted negative
based on structure
Oxidizing Properties
(Solids)
Not oxidizing
Not oxidizing
Corrosion to Metals
Predicted not to
corrode metals due to
high melting point
Predicted not to
corrode metals due to
high melting point
Flammable Solids
Self Heating
Substances
4.Mammalian and environmental hazard
comparison
A comparison of potential mammalian and environmental
hazards of Pyrolusite and EMD, as defined through routine
regulatory tests to identify sameness, has been undertaken.
These tests were conducted in accordance with the OECD
guidelines; the results are shown in Table 2. The results show
that for the mammalian endpoints, Pyrolusite is classified only
as a mild eye irritant while EMD is classified for acute toxicity.
Neither Pyrolusite nor EMD is classified for the environment.
Table 2. Comparison of mammalian and environmental hazard assessment
of Pyrolusite and EMD
Studies
Pyrolusite Ore
EMD
Result
Result
Acute oral toxicity
Not classified
Classified as H302 –
Harmful if swallowed
Acute inhalation
toxicity
Not classified
Classified as H302 –
Harmful if inhaled
Not irritating/corrosive
to the skin
Not irritating/corrosive
to the skin
Mild eye Irritant
Not irritating
to the eyes
TDp at pH 6 – 24hr
screening (worse
case pH)
<5µg Mn L-1
22 µg Mn L-1
Ecotoxicity studies
– Acute fish, algal
inhibition, acute
daphnia magna, etc.
Studies not conducted
due to negligible
release to the
environment
All studies confirmed
no potential toxicity to
aquatic species
Environmental toxicity
evaluation
Assumed not to
be harmful to the
environment- release
to the environment
is below background
levels
Based on the studies
conducted, the
substance does not
meet the criteria
for environmental
classification
Mammalian
assessment
In vitro Skin irritation/
corrosion
In vitro eye irritation
Environmental
assessment
5. Conclusions
Both Pyrolusite and EMD are inorganic, insoluble solids and are
commonly referred to as MnO2. However, the substances are
not structurally similar and their physico-chemical properties,
which drive their toxicokinetic behaviour, are different, as the
mammalian and environmental hazard assessment show. This
means that the intrinsic hazardous properties from one cannot
be read across to the other; therefore available data for one
cannot be used to fill-in data gaps for the other. The Pyrolusite
ore is clearly NOT the same as EMD, hence reading across
data or classification and labelling information from EMD to
Pyrolusite is not scientifically justifiable.
Further information:
There are more fact sheets in this series: Fact Sheet 1. The derivation of limit values for manganese and its compounds in
freshwater: data availability, Fact Sheet 2. Construction of the biotic ligand models for manganese, Fact Sheet 3. Accounting
for bioavailability in assessing potential risks of manganese in freshwater, Fact Sheet 4. Assessing the potential terrestrial risks
from manganese, and Fact Sheet 5. Life Cycle Assessment (LCA) aimed at measuring the overall environmental performance
of the global manganese alloy industry, Fact Sheet 6. Manganese in Groundwater: Research and potential risks, Fact Sheet 7.
Occupational Exposure Levels for Manganese (OEL), Fact Sheet 8. Manganese - reassuring evidence about male reproductive
health effects. Fact Sheet 9. Manganese Industry - Socio-Economic Assessment. You can find them at: http://www.manganese.
org. For more information please contact: [email protected].
August 2014
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