L10 - Iron and Manganese

Question 1

What are the uses of iron and manganese?

Answer 1

Used in blood cells, as industrial additives to steel for strength, and in medicines.

Question 2

What is the enrichment to ore grade for iron and manganese?

Answer 2

Iron (Fe) is enriched 5x, and manganese (Mn) is enriched 220x

Question 3

What are the atomic numbers and masses of iron and manganese?

Answer 3

• Iron (Fe): Atomic number 26, atomic mass 55.845.
• Manganese (Mn): Atomic number 25, atomic mass 54.938.

Question 4

What are the melting points and densities of iron and manganese?

Answer 4

• Iron: Melting point 1538°C, density 7.87 g/cm³.
• Manganese: Melting point 1246°C, density 7.3 g/cm³.

Question 5

How do iron and manganese compare in hardness?

Answer 5

Iron has a hardness of 4, while manganese has a hardness of 6.

Question 6

What are the key ferrous and ferric iron minerals?

Answer 6

Ferrous (Fe²⁺): Siderite. Ferric (Fe³⁺): Hematite, chamosite, geothite, pyrite, limonite.

Question 7

What are the key manganous and manganic manganese minerals?

Answer 7

Manganous (Mn²⁺): Rhodochrosite. Manganic (Mn³⁺/Mn²⁺): Braunite, kutnahorite, hausmannite

Question 8

Which iron mineral is highly magnetic?

Answer 8

Magnetite

Question 9

Which manganese mineral is commonly used in batteries?

Answer 9

Pyrolusite

Question 10

What is the key redox chemistry for iron?

Answer 10

2Fe²⁺ + 3CO₂ ↔ Fe₂O₃ + 3CO

Question 11

What is the key redox chemistry for manganese?

Answer 11

2Mn²⁺ + O₂ + 2H₂O ↔ 2Mn⁴⁺O₂ + 4H⁺

Question 12

Where are the major reserves and production areas for iron?

Answer 12

• Production: Australia (38%), Brazil (17%).
• Reserves: Australia (30%), Brazil (18%), Russia (15%)

Question 13

Where are the major reserves and production areas for manganese?

Answer 13

Production: South Africa (36%), Gabon (23%).

Reserves: South Africa (32%), Australia (26%).

Question 14

What deposit types are common for both iron and manganese?

Answer 14

Marine chemical sediments, volcanic exhalations, hydrothermal veins, meteoric fluids/surface weathering.

Question 15

What deposit types are exclusive to iron?

Answer 15

Magmatic and metamorphic fluids.

Question 16

What is a key feature of banded iron formations?

Answer 16

Distinct banding and stratigraphy, formed around 2.7 billion years ago.

Question 17

What are the depositional processes for iron?

Answer 17

Redox processes, oxygenic photosynthesis, and abiogenic oxidation.

Question 18

What is a notable manganese deposit?

Answer 18

The Kalahari manganese field, with concentrations of 20–48% Mn and ore bodies up to 45m thick

Question 19

What geophysical techniques are used in exploration for iron and manganese?

Answer 19

Magnetic surveys for magnetite and gravity surveys for dense ore minerals

Question 20

What environmental issues arise from iron and manganese mining?

Answer 20

Acid mine drainage, asbestos exposure, and destruction of cultural sites (e.g., Rio Tinto blasts).

Question 21

How is acid mine drainage formed from sulfidic iron ores?

Answer 21

4FeS₂ + 15O₂ + 8H₂O → 2Fe₂O₃ + 8SO₄²⁻ + 16H⁺.

Question 22

What are the primary uses of iron and manganese?

Answer 22

Iron and manganese are primarily used in the steel and construction industries, as well as in batteries and the chemical industry.

Question 23

What are the major deposit types for iron and manganese?

Answer 23

Marine chemical sediments, laterites, volcanic exhalations, hydrothermal veins, and skarns.

Question 24

Why are Proterozoic iron and manganese formations significant?

Answer 24

They provide insights into the early atmosphere and the first oxygenation events