Question

Among the following ores Bauxite, Siderite, Cuprite, Calamine, Haematite, Kaolinite, Malachite, Magnetite, Sphalerite, Limonite, Cryolite, the number of principal ores of iron is____.

Answer 1

Correct Answer: 4

To determine the number of principal ores of iron among the given list, we first need to identify which items are indeed ores of iron:

• Bauxite: An ore of aluminum, not iron.
• Siderite: An iron carbonate ore (FeCO₃), hence a principal ore of iron.
• Cuprite: An ore of copper, not iron.
• Calamine: Refers to zinc ores, not iron.
• Haematite: An iron oxide ore (Fe₂O₃), hence a principal ore of iron.
• Kaolinite: A clay mineral, not an iron ore.
• Malachite: An ore of copper, not iron.
• Magnetite: An iron oxide ore (Fe₃O₄), hence a principal ore of iron.
• Sphalerite: An ore of zinc, not iron.
• Limonite: An amorphous iron oxide, typically containing hydrated iron(III) oxides, hence a principal ore of iron.
• Cryolite: Used in aluminum processing, not an iron ore.

The principal ores of iron identified are Siderite, Haematite, Magnetite, and Limonite. Thus, there are 4 principal iron ores in the list.

Checking the solution against the expected range (4,4), 4 is indeed within this range. Therefore, the computed number of principal ores of iron is correct.